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Before the
FCC 96-36
Washington, D. C. 20554
In the Matter of)

Amendment of Parts 2 and 15 of the    )    ET Docket No. 96-8
Commission's Rules Regarding Spread   )    RM-8435, RM-8608, RM-8609
Spectrum Transmitters   )

Adopted: January 30, 1996 ; Released: February 5, 1996

Comment Date: [75 days from date of publication in the Federal Register]
Reply Comment Date: [105 days from date of publication in the Federal Register]

By the Commission:


      1. By this action, the Commission proposes to amend Parts 2 and 15 of the rules regarding the operation of spread spectrum transmission systems in the 902-928 MHz, 2400- 2483.5 MHz and 5725-5850 MHz bands. Specifically, we are proposing to eliminate the limit on directional gain antennas for spread spectrum transmitters operating in the 5800 MHz band. We are also proposing to reduce, from 50 to 25, the minimum number of channels required for frequency hopping spread spectrum systems operating in the 915 MHz band. These proposals are in response to Petitions for Rule Making filed by Western Multiplex Corporation (WMC) and SpectraLink Corporation (SpectraLink), respectively. We also are denying a Petition for Rule Making from Symbol Technologies, Inc. (Symbol) that seeks a reduction in the minimum number of required hopping channels, from 75 to 20, for frequency hopping spread spectrum systems operating in the 2450 MHz and 5800 MHz bands. On our own motion, we are proposing a number of amendments to the spread spectrum regulations to clarify the existing regulations, to codify existing policies into the rules, and to update the current definitions. The changes will expand the ability of equipment manufacturers to develop spread spectrum systems for unlicensed use.


      2. Part 15 of the regulations permits the operation of radio frequency devices without a license from the Commission or the need for frequency coordination. The technical standards for Part 15 transmission systems are designed to ensure that there is a low probability that these devices will cause harmful interference to other users of the spectrum. Indeed, the primary operating conditions under Part 15 are that the operator must accept whatever interference is received and must correct whatever interference is caused.

      3. Spread spectrum communications systems use special modulation techniques that spread the energy of the signal being transmitted over a very wide bandwidth. The information to be conveyed is modulated onto a carrier frequency by some conventional technique, such as AM, FM or digital, and the bandwidth of the signal is deliberately widened by means of a spreading function. The spreading technique used in the transmitter is duplicated in the receiver to enable detection and decoding of the signal. This spreading reduces the power density of the signal at any frequency within the transmitted bandwidth, thereby reducing the probability of causing interference to other signals occupying the same spectrum. In addition, the signal processing tends to suppress undesired signals, enabling these systems to tolerate strong interference.

      4. Two types of spread spectrum systems are permitted under the Part 15 regulations: direct sequence systems and frequency hopping systems. Direct sequence systems modulate the carrier with a combined information signal and a much faster binary code signal. The binary code signal is a fixed-length pseudorandom sequence of bits. It dominates the modulating function and is the direct cause of the spreading of the transmitted signal. Frequency hopping systems spread their energy by changing, or "hopping," the center frequency of the transmission in accordance with a pseudorandomly generated list of channels.

      5. The existing regulations limit spread spectrum systems to a maximum peak transmitter output power of one watt. When operating at that power level, the maximum directional gain of the associated antenna may not exceed 6 dBi, resulting in a maximum equivalent isotropically radiated power (EIRP) of four watts. Direct sequence systems must employ a minimum 6 dB bandwidth of 500 kHz with a processing gain of at least 10 dB. Frequency hopping systems in the 915 MHz band must use at least 50 hopping channels with a maximum 20 dB channel bandwidth of 500 kHz, while hopping systems in the 2450 MHz and 5800 MHz bands must use at least 75 hopping channels with a maximum 20 dB channel bandwidth of 1 MHz.


Western Multiplex Corporation (WMC)

      6. The Petition. WMC filed a combined Petition for Rule Making and Request for Immediate Waiver with the Commission. It requests that the limits on antenna gain be removed for spread spectrum systems operating in the 2450 MHz and 5800 MHz bands. WMC also requests a waiver of this regulation pending consideration of the Petition for Rule Making by the Commission. In its petition and comments, WMC indicates that spread spectrum systems employing antennas with levels of gain higher than that permitted under the current rules are being used to provide 1.5 Mbps T1-type links without having to go through a frequency coordination and licensing process. It states that this enables rapid setup of the system and reduces costs to the user. WMC states that typical users include manufacturing and service companies, oil and gas pipeline companies, mobile and SMR operators, common carriers, public safety services, state and local governments and the U.S. Government. WMC states that typical applications include communications to oil platforms, emergency restoration of communications in disaster situations, low density spurs off microwave fiber optic backbone systems to serve remote field offices and service centers, extensions of local area networks, law enforcement and fire prevention communications, transmission of supervisory control and data acquisition circuits, seismic monitoring equipment transmissions, data transmissions, remote control of stacker reclaimer equipment, power plant control yard communications, and connections of mobile radio cell sites to the main telephone switching site. WMC argues that there are no known cases of harmful interference involving these transmitters operating with higher antenna gains. As stated by WMC, the use of directional (high gain) antennas, because of the line of sight propagation characteristics above 2 GHz, permits greater reuse of frequencies in an given area and yields a significantly higher transmission capacity per unit bandwidth than can be achieved using non-directional (low gain) antennas.

      7. Most of the commenting parties support WMC's request. Two parties, Alcatel Network Systems, Inc., (Alcatel) and WINDATA, Inc., (WINDATA), oppose this request. Alcatel states that the WMC proposal could have the effect of reallocating the 2450 MHz and 5800 MHz bands for point-to-point use by unlicensed devices, whereas these bands could be used more efficiently by licensed microwave systems. WINDATA states that the use of higher gain antennas could result in unacceptable interference, especially to indoor Part 15 spread spectrum systems, such as wireless local area networks, that could be in the main beam of a WMC system.

      8. Cylink Corp., Metricom, Inc., and Tetherless Access Ltd. filed comments requesting that the limit on maximum directional antenna gain also be deleted for systems in the 915 MHz band. This request was opposed by Pinpoint Communications, Inc., which expresses concern for potential interference by spread spectrum systems to its automatic vehicle monitoring system/location monitoring service operating in the same band under Part 90 of our regulations.

      9. Discussion. We recognize the advantages of being able readily to establish radio links capable of transmission distances of 10 km, or greater, without the delays and costs associated with frequency coordination and licensing. The ability to establish such transmission links quickly could be critical in emergency situations. However, because the use of high power radio links without prior frequency coordination could result in significant interference problems to other operators using these frequency bands, we believe it is necessary to restrict their use. The frequency bands addressed in the WMC petition are allocated for operation by industrial, scientific and medical devices, U.S. Government stations, the Amateur Radio Service, the Private Land Mobile Radio Services, the Private Operational- Fixed Microwave Services, and Television Broadcast Auxiliary Stations. The other spread spectrum band, the 915 MHz band, is allocated for operation by industrial, scientific and medical devices, the Private Land Mobile Radio Services, and the Amateur Radio Service. Accordingly, we are proposing to eliminate the antenna directional gain limit only for non- consumer, fixed, point-to-point spread spectrum systems operating in the 5800 MHz band.

      10. The spread spectrum rules, as originally adopted, did not specify a limit on antenna gain. At that time, there were few other operators in these bands and little potential that interference would be caused to other users. Further, we wished to offer an incentive to spur the development of spread spectrum systems. These bands, especially the 915 MHz and the 2450 MHz bands, are now becoming more crowded, particularly with mobile units, increasing the potential that spread spectrum systems using high gain antennas will cause harmful interference. In addition to the licensed radio services, wireless computer local area network systems and various consumer products, such as cordless telephones, are being used under Part 15 in the 915 MHz and 2450 MHz bands.

      11. However, as there are few operators in the 5800 MHz band, the potential that harmful interference will occur from the use of directional antennas is much lower. There are also fewer mobile users in the 5800 MHz band. It is easier to engineer a fixed, point-to-point system to operate without causing harmful interference problems if the other stations in that band are fixed in location. Further, the 5800 MHz band is ideal for fixed, point-to-point wideband microwave operations, the type of applications desired by WMC. Accordingly, we believe the limit on directional antenna gain should only be eliminated for spread spectrum systems operating in the 5800 MHz band. We request comment on this proposal. While we are not inclined to provide a similar relaxation for the 2450 MHz band, we also ask for comment on whether we should eliminate the 6 dB limit on directional antenna gain in this band.

      12. While the use of high gain directional antennas can reduce the potential for interference to radio operations located outside the directional beam of the antenna pattern, the potential for harmful interference to radio systems located in the beam of the directional antenna increases significantly. Obviously, if multiple antennas are employed, providing point-to-multipoint or omnidirectional operation, the coverage area increases, but so does the potential for harmful interference. In addition, we recognize that the use of high gain directional antennas benefits primarily fixed applications. Therefore, we also believe that the restriction on directional antenna gain should be eliminated only for those 5800 MHz systems used for fixed, point-to-point operations. This proposal would not eliminate the limit on antenna gain for point-to-multipoint or omnidirectional systems, transmitters employing multiple directional antennas, or multiple co-located transmitters transmitting the same information.

      13. We further believe that if spread spectrum transmitters employing high gain antennas were made available to the general public, it would be difficult to ensure that these systems are used only for fixed, point-to-point applications. In addition, high gain directional antenna systems, because of their narrow transmission beamwidth and the problems associated with aligning the transmitter with the receiver site, are not products that would normally be employed by the general public. Further, as indicated by WMC and the supporting comments, these high gain transmission systems are being employed by commercial and industrial operators for communication back-haul systems in order to avoid the expenses and delays associated with licensed systems. Accordingly, we believe that the marketing of spread spectrum systems employing high gain antennas should be limited to commercial or industrial operators and exclude sales to the general public. We further propose to hold the operator of a spread spectrum system responsible for ensuring that the system is operated in a compliant manner. In addition, we propose to require that the manual supplied with the spread spectrum transmitter contain language in the installation instructions notifying the operator of this responsibility. Commenting parties should note that the transmitter must be authorized under our certification procedure along with the specific antenna with which it will be used. These components are authorized as a system to ensure that the emission limits, especially those limits designed to protect other sensitive radio services or services used for safety-of-life applications, are not exceeded.

      14. Absent controls regarding the locations and manner in which spread spectrum transmitters may be used, systems employing high gain directional antennas could expose the public to potentially harmful signal levels that exceed the radio frequency exposure limits of our rules and recommended by various standards-setting organizations. In order to meet our obligation under the National Environmental Policy Act, we propose to hold the holder of the grant of certification for the transmitter, the grantee, responsible for ensuring that the equipment is designed to minimize exposure of the public to excessive radio frequency (RF) signal levels. While we proposed to make the operator responsible for ensuring that the system is used only for fixed, point-to-point applications, the means to prevent excessive exposure levels can be incorporated into the equipment design. In addition, absent some action by the grantee to incorporate a warning into the equipment, the operator would not necessarily realize that there was a potential for excessive RF exposure levels. A possible method is a sign, attached to the antenna and of sufficient size and visibility, warning the public of the potential danger of RF exposure. Another possible method is the incorporation of proximity sensors that cause the transmitter to automatically decrease output power if someone wanders too close to the transmitting antenna. Comments are requested concerning possible biological hazards from the high effective radiated power levels that could be emitted from these systems, any additional methods that can be employed to prevent unnecessary exposure of the public, and whether we should prescribe the use of specific means for preventing such exposure.

      15. Commenting parties should note that informal comments raising concerns with the WMC petition, particularly operation in the 2450 MHz band, have already been received from the staff at Industry Canada, an agency of the Canadian Government. Similarly, the Mexican Government has expressed its concern regarding unlicensed spread spectrum operations between stations in the U.S. and stations in Mexico. Thus, commenting parties may also wish to address actions that could be taken to limit operation near the Canadian and Mexican borders to avoid unauthorized crossborder operations and interference to licensed systems in Canada and Mexico.

      16. Comments are also requested in two additional areas regarding the technical standards for spread spectrum transmission systems operating without a limit on directional antenna gain. The first of these concerns a reduction in the output power of the transmitter based on the amount that the increase in directional antenna gain exceeds the current limit of 6 dBi. We propose that the output power of a transmitter would need to be decreased by 1 dB for every 3 dB that the antenna gain exceeds 6 dBi in order to maintain an "equivalent" area of interference, i.e., the geographic area over which interference could result with a directional antenna as compared to the area obtained with an omnidirectional antenna. While this would result in a slight reduction in the effective radiated power level of the system, the higher gain employed by the antenna would still be available to amplify the received signal.

      17. Comments are also requested on whether the rules should specify limits on the horizontal and vertical beamwidths of antennas used with these point-to-point systems. Certain antenna designs, e.g., a horizontally polarized yagi antenna, concentrate the signal strength in azimuth (horizontal) but not in elevation (vertical). However, a fixed, point-to- point system employing an antenna with a wide elevation beamwidth that is pointed towards an office building with multiple floors could result in severe interference problems to any party in that building who is in line with the system and is operating in the same band. Several antenna designs concentrate the radiated signals in both azimuth and elevation, e.g., circular dish antennas and stacked yagi antennas. We believe that any interference problems resulting from excessive vertical emissions could be resolved if the 3 dB beamwidths, in both the vertical and the horizontal planes, of the high gain directional antennas employed with these fixed, point-to-point systems differ by no more than a factor of two and are proposing such a limit.

Symbol Technologies, Inc. (Symbol)

      18. The Petition. In its Petition for Rule Making, Symbol requests a reduction in the number of hopping channels, from 75 to 20, required for frequency hopping spread spectrum systems operating in the 2450 MHz and 5800 MHz bands. Under this plan, the average time of occupancy for the hopping transmitter would be limited to no longer than 0.4 seconds on any one channel in any 8 second interval, as opposed to the current limit of 0.4 seconds on any one channel in any 30 second interval. Further, the output power would be reduced from the current one watt peak output to (number of hops/75) watts. Symbol indicates that the proposed changes would raise the effective signal bandwidth of a frequency hopping system from 1 MHz to about 5 MHz.

      19. Symbol states that its proposed changes would align U.S. standards for unlicensed spread spectrum systems more closely with the European standards for such equipment, permitting U.S. manufacturers to produce the same equipment for domestic use and for export to Europe. It adds that this, in turn, would reduce the cost of exported goods and increase U.S. exports to Europe. Symbol further states that its proposed language is compatible with the European Telecommunications Standards Institute standard ETS 300-328 for the 2450 MHz band. Symbol also indicates that frequency hopping equipment manufactured under this proposal would be capable of substantially higher data speeds than can be achieved under the present frequency hopping rules. It states that such systems could be used to satisfy customer demands for high speed, low cost wireless computer local area networks (LANs), making it possible for wireless LANs to compete with wired LANs while offering the wireless advantage of portability and flexibility. Symbol also argues, in its petition, that these amendments would not increase the threat of interference to other users in this spectrum. Further, Symbol adds that the proposed changes to the rules would correct a competitive disparity between direct sequence systems and frequency hopping systems. Finally, Symbol adds that its proposal would not significantly detract from the major advantages of spread spectrum long recognized by the Commission: its ability to enhance spectrum efficiency by sharing spectrum with other services in ways that minimize cross-interference.

      20. Comments. Apple Computer, Inc. (Apple), Norand Corporation (Norand), and SpectraLink Corporation (SpectraLink) filed comments supporting Symbol's petition. Norand states that these proposals would foster the joint development of products for both the U.S. and the European markets. Norand also concurs with Symbol's assessment that the proposed changes would not increase the potential for interference to other radio operations, and that frequency hopping systems operating under these relaxed standards would create no greater interference potential than currently caused by direct sequence systems. Apple expresses support for Symbol's proposal, stating that these changes would permit wireless LANs to operate at higher data rates while protecting other users of the band from increased interference and would harmonize our rules with European standards. Apple, however, also adds that Symbol's proposal does not appear to address the risk that narrow band systems employing a few hopping channels could dominate a frequency range and cause that range to appear occupied and unavailable to devices employing wideband channels. Apple is also concerned that the adoption of this proposal could adversely affect the efforts of the Institute of Electrical and Electronic Engineers (IEEE) Standards Working Group P802.11 to develop industry-wide standards for wireless LANs. Apple submits that other Commission actions, including the allocation of spectrum at 2390-2400 MHz and the development of the millimeter wave bands above 40 GHz, may also provide new opportunities for high bandwidth wireless transmissions. SpectraLink concurs with Symbol that a reduction in the minimum number of frequency hopping channels, coupled with a corresponding increase in the permissible channel bandwidth, would allow a higher data throughput, but also urges us to stipulate that the maximum transmitter dwell time per hop on any channel may not exceed 0.4 seconds.

      21. In addition to the concerns raised by Apple, Aironet Wireless Communications, Inc. (Aironet) and AT&T oppose Symbol's request. Aironet contends that the proposed changes would lead to potentially serious interference to other spread spectrum users as well as to primary (licensed) users of these bands. It also states that the use of wider bandwidth transmissions would significantly reduce the processing gain and interference rejection capabilities of frequency hopping systems. Aironet agrees that there will be substantial demand for wireless LANs, but argues that these systems should use direct sequence and other technologies which, it contends, are more than sufficient to meet the technical requirements for wireless LANs. In regard to Symbol's statement that its proposal is similar to European standards, Aironet states that the new European standards came into effect after considerable controversy in 1994, and very few, if any, of these frequency hopping systems have been developed in Europe to date because of the continuing controversy within the industry. AT&T also expresses concern that these rule changes would increase the potential for interference to other devices in the bands. It states that frequency hopping systems using a wider bandwidth would have a greater chance of transmitting on a frequency used by a nearby system and, thus, interfering with that other system. AT&T further states that with fewer hopping channels, frequency hopping systems would frequently collide with each other and with direct sequence systems. This interference would increase as spread spectrum systems proliferate.

      22. Some of the comments addressed methods that could provide additional versatility for frequency hopping spread spectrum systems. Apple indicates that it may be advantageous to consider possible alternative numbers of hopping channels, as well as changes in output power for increased bandwidth transmissions. Metricom, Inc. (Metricom) states that the Commission should specify the maximum bandwidth of a hopping channel as a function of the number of hopping channels and should specify a channel distribution in order to ensure that there is an even distribution over the entire frequency band employed. This would prevent the band from becoming "channelized" and would prevent the "bunching" of frequency hopping channels in any particular segment of the spectrum.

      23. Discussion. We have serious concerns that implementing Symbol's requested changes could result in severe increases in the potential for harmful interference, both to the authorized radio services and to other Part 15 devices operating in these bands. Symbol's request to decrease the number of hopping channels would result in an increase in the average time during which the channels are occupied by a spread spectrum transmission. In addition, Symbol's request to increase the bandwidth of the hopping channels would broaden the spectrum over which interference from the frequency hopping systems could be received. Thus, we believe that implementing these changes would be detrimental to other narrowband and wideband systems operating in these bands. While this increased interference potential could be partially offset by a reduction in the output power of the frequency hopping transmitters, we are not convinced that a linear power reduction alone is sufficient to offset this interference potential. We also note that any benefit from the reduction in output power could be negated if we adopt the proposal from WMC, described above, to eliminate the current restriction on antenna gain in the 5800 MHz band. In addition, the resulting increase in hopping channel bandwidth would open frequency hopping systems to several new consumer applications, such as analog video transmissions, in addition to the wireless local area network applications described in the petition. Normally, the Commission seeks to encourage new uses of the spectrum. However, in this case we feel that the large increase in the proliferation of these transmitters from additional consumer applications, combined with a smaller number of hopping channels, an increased bandwidth, and increase in average channel occupancy time, and, in some cases, a higher effective radiated power, would result in a significant increase in the probability that harmful interference will occur to other radio operations in these bands.

      24. We also observe that there appears to be sufficient spectrum, either currently available or under proposal, to support high data speeds for wireless local area network systems. For example, we have opened 5 GHz of spectrum in the 59-64 GHz band, and have proposed to open additional bands above 40 GHz, for consumer applications. In addition, licensed wideband digital transmission systems may be operated under the Personal Communications Services, the Private Land Mobile Radio Services, and the Private Operational Fixed Microwave Service. Unlicensed wideband digital signals may also be transmitted in the 2450 MHz and 5800 MHz bands using either direct sequence spread spectrum modulation or, at a lower power level, conventional modulation techniques and in the bands 1910-1920 MHz and 2390-2400 MHz. In addition, it is possible under the existing rules to construct frequency hopping systems in the 2450 MHz and 5800 MHz bands that can operate at high data rates through the use of more efficient modulation techniques, such as quadrature amplitude modulation. We are also considering the possibility of providing additional spectrum for unlicensed operations under a Petition for Rule Making from Apple to open the frequency bands at 5150-5300 MHz and 5725-5875 MHz as well as a Petition for Rule Making from the Wireless Information Networks Forum (WINForum) to open spectrum at 5100-5350 MHz.

      25. Finally, as indicated in the comments, the IEEE Standards Working Group P802.11 is currently developing industry standards for wireless LANs, including operation in the 2450 MHz band. We are reluctant to propose any changes to the existing spread spectrum standards regarding the transmission of wideband digital systems prior to the release of that Committee's recommendations. While we agree with Symbol that harmonization with the European standards would be advantageous, harmonization is not sufficient, by itself, to overcome all of the potential problems associated with reducing the minimum number of hopping channels. Accordingly, in light of the above considerations we are denying the Petition for Rule Making from Symbol to reduce the minimum number of hopping channels for frequency hopping spread spectrum systems operating in the 2450 MHz or 5800 MHz bands.

SpectraLink Corporation (SpectraLink)

      26. The Petition. In its Petition for Rule Making, SpectraLink requests a reduction, from 50 channels to 25 non-contiguous channels, in the number of hopping channels required for frequency hopping spread spectrum systems operating in the 915 MHz band. SpectraLink also requests that frequency hopping systems that use fewer than 50 hopping channels be limited to a maximum transmitter peak output power of 500 mW. It states that a system operating with 25 hopping channels and a corresponding 3 dB reduction in output power would have the same spectral power density as a system using 50 hopping channels.

      27. Adoption of the SpectraLink proposal would allow a reduction, from 25 MHz to 12.5 MHz, in the minimum spectral occupancy of frequency hopping spread spectrum systems operating at the maximum channel bandwidth. SpectraLink indicates that this is necessary because of the recent rule making actions by the Commission allocating the 915 MHz band to the Location Monitoring Service (LMS) under Part 90 of our rules. By decreasing the number of frequency hops, Part 15 spread spectrum systems could avoid operating in the frequency bands used by wideband multilateration LMS systems, preventing mutual interference problems. SpectraLink indicates that this change to reduce the spectral occupancy of spread spectrum systems would maximize the number of Part 15 devices and LMS users that can coexist in the band, would accommodate the future deployment of frequency hopping systems in the band, and would maximize spectral efficiency.

      28. Comments. All of the commenting parties generally support SpectraLink's petition. Most parties cite SpectraLink's proposals as an effective means of avoiding the bands used by wideband multilateration LMS systems and state that such an approach would avoid potential interference problems both to and from Part 15 spread spectrum systems. Apple notes that wideband systems utilize virtually the entire 915 MHz band and must hop to, and transmit in, portions of the band that have been allocated to multilateration LMS systems. It adds that SpectraLink's proposal to reduce the number of hopping channels, with an attendant power reduction to retain the same spectral power density, has substantial merit and few, if any, downside results. Apple also points out that since the rule change provides only further latitude, not further restrictions, it will not force Part 15 manufacturers who are content with the current rules to redesign their products.

      29. Itron, Inc. requests that the Commission provide a graded power curve based on the number of hopping channels actually used by the spread spectrum transmitter. It adds that the power reductions should be correlated linearly to the number of frequencies on which a device hops. Metricom, however, states that the proposed 500 mW output power limit doesn't fully address the potential for crowding if many transmitters begin to concentrate in the remaining portion of the 915 MHz band. It submits that the potential for interference is exponential, not linear, due to the statistical nature of systems' response to interference (collisions). Metricom also points out that SpectraLink indicates that its products will operate indoors. According to the new rules regarding sharing between Part 15 devices and the LMS, LMS systems are not protected from interference from Part 15 devices that operate indoors. Thus, Metricom contends that SpectraLink's claim of needing to reduce the number of hopping channels to avoid interference between Part 15 and LMS devices is not sufficient to justify changing the rules.
      30. Discussion. As SpectraLink observes, there could be mutual interference problems between wideband, multilateration LMS systems and Part 15 frequency hopping spread spectrum systems, and it would be beneficial if these two operations could avoid sharing the same spectrum. The modification sought by SpectraLink would appear to promote frequency sharing within this band. For these reasons, we believe that the SpectraLink petition, unlike the petition from Symbol, should be adopted. Therefore, we are proposing to amend the rules to permit frequency hopping spread spectrum systems in the 915 MHz band to use only 25 hopping channels, provided that those systems employ hopping channel bandwidths of at least 250 kHz and the transmitters operate at a reduced power level. Hopping systems using channel bandwidths less than 250 kHz already can avoid operating in the bands used by broadband multilateration LMS systems and require no decrease in the minimum number of hopping channels. For frequency hopping systems employing channel bandwidths of 250 kHz or greater, we propose to reduce the minimum number of hopping channels to 25. Consistent with this plan, we are also proposing to modify the maximum average time of occupancy on any hopping frequency to 0.4 seconds in any 10 second period to correspond to the reduction in the number of hopping channels.

      31. While SpectraLink's petition raises some of the same interference concerns as the Symbol petition, we see several important differences. We note that, unlike Symbol's request, there would be no increase in the bandwidth of the hopping channel. In addition, the reduction in the number of hopping channels and the corresponding increase in the average channel occupancy time would not be as great as under Symbol's proposal. Further, unlike operation in the 2450 MHz and 5800 MHz bands, we note that multilateration LMS services are expected to grow at a rapid rate, causing frequency congestion problems for Part 15, LMS and other users of the 915 MHz band.
      32. We also request comments as to whether the rules should specify a formula for the minimum number of hopping channels based on the amount by which the bandwidth of the hopping channel exceeds 250 kHz. Under this approach, the minimum number of hopping frequencies would be equal to 25 x (500/20 dB bandwidth of a single hopping channel in kHz) or 50 hopping frequencies, whichever results in the lowest number of hopping frequencies. The use of this formula would result in an even distribution of the hopping channels over that portion of the 915 MHz band that is not employed by wideband multilateration LMS systems. This would prevent frequency hopping systems employing between 250 kHz and 500 kHz bandwidth hopping channels from being concentrated in any single portion of the 915 MHz band. Adopting this formula would also require that the average time of occupancy on any hopping frequency not exceed 0.4 seconds within a 20 x (number of hopping channels/50) second period.

      33. In order to reduce the potential for interference due to the smaller number of hopping channels, we propose to require that frequency hopping spread spectrum systems in the 915 MHz band that use fewer than 50 hopping channels operate with a maximum peak transmitter output power of 500 mW. However, as suggested by Metricom, while the potential for harmful interference can be offset by a reduction in operating power, a linear reduction may not be sufficient to provide this offset. We recognize that the chance of collisions with other transmissions, and resulting interference, will be increased since there are a fewer number of hopping channels resulting in a change to the average time of occupancy on any frequency and the crowding of transmissions into less spectrum. Accordingly, comments are requested as to whether or not a greater reduction in output power should be applied. Comments are also requested on whether a limit on spectral power density, similar to that currently applied to direct sequence systems, should be applied to frequency hopping systems operating with less than 50 hopping channels. We also request comments regarding Itron's suggestion to specify a linear power reduction based on the actual number of hopping channels employed. This would result in a maximum peak transmitter output power of no greater than (number of hopping channels/50) watts or 1 watt, whichever is the lesser power.

      34. Commenting parties should note that a number of petitions for reconsideration have been received in response to the recent Report and Order implementing the LMS system. Any changes to the LMS rules in response to those petitions may result in modifications to changes for the spread spectrum regulations under Part 15 proposed for the 915 MHz band.


      35. There are several additional regulations concerning Part 15 spread spectrum transmission systems that need to be clarified, codified or amended. These are discussed below.

      36. Most U-NII proponents support allowing higher power and higher antenna gain in the U-NII spectrum. They claim that the propagation characteristics at 5 GHz are such that operation at power levels higher than the proposed limit is required to provide reliable communications for most local-area networks and for longer-range networks. They state that the signal attenuation caused by walls is one of the primary reasons why higher power is needed for LANs. Higher power, they state, is also needed for community networks to achieve reliable communications over the necessary distances. For example, WINForum argues that, in order to meet on-premises communication requirements, the maximum transmitter output power limit in the 5.15-5.35 GHz band should be 100-250 mW (-10 to -6 dBW), and directional antennas should be permitted with up to 6 dBi gain. It also suggests allowing use of even higher gain antennas, as long as the transmitter power is decreased on a dB-for-dB adjustment basis (i.e.,transmitter output power would be decreased by one dB for every dB increase in antenna gain). WINForum states that these maximum power and gain parameters would provide a desirable balance between permitting sufficient in-building signal penetration by U-NII devices and ensuring adequate interference protection to incumbent 5 GHz and other U-NII operations.

      37. Apple supports adoption of a maximum transmitter output power of 100 mW (-10 dBW) in the 5.15-5.25 GHz band. Apple states that this power limit would protect incumbent operations and would allow the lower power band to be used for personal/portable type operations that would generally operate indoors. Apple also argues for a higher limit on transmitter output power in the 5.25-5.35 GHz and 5.725-5.825 GHz bands. Specifically, Apple states that we should set the power limit at 316 mW (-5 dBW), with unrestricted antenna gain in these bands. It claims higher power is needed in these bands to provide for fixed point-to-point operations that would meet the requirements of community networks.

      38. WINForum also urges the Commission to adopt higher power and antenna gain limits for the upper band, 5.725-5.825 GHz. It notes that Part 15 spread spectrum devices in this band are currently authorized to operate with up to 1 W transmitter output power and with up to 6 dBi of antenna gain. Further, it notes that even higher power limits for spread spectrum devices are currently under consideration by the Commission in ET Docket 96-8.

      39. Motorola recommends adoption of a maximum transmitter output power limit of 250 mW in the 5.15-5.35 GHz band, and 1 W in the 5.725-5.825 GHz band, for bandwidths equal to or greater than a certain threshold, e.g., 25 megahertz. Motorola also supports allowing transmitter antenna gains of up to 23 dB in both bands, without any associated reduction in transmitter output power. Motorola argues that directional transmitter antennas will provide reliable communications with lower risk of interference. It further states that U-NII device power limitations should be based on the output power spectral density to reduce interference concerns irrespective of the emission bandwidth. That is, transmitter output power should be reduced in direct proportion to any reduction in emission bandwidth below some threshold. With regard to community network links, Motorola recommends that, consistent with the proposal in ET Docket No. 96-8, the Commission allow the use of even higher gain transmitter antennas whenever the transmitter output power is reduced by 1 dB for each 3 dB of antenna gain above 23 dB.

      40. Mulcay points out that the proposed 100 mW (-10 dBW) EIRP limit is substantially lower than the European HIPERLAN standard of 1 W (0 dBW) EIRP. Mulcay states that the maximum transmitter output power limit for U-NII devices should therefore be raised to 1 W (0 dBW) EIRP to be consistent with the HIPERLAN limit. It claims this would facilitate U.S. firms' ability to compete in global markets.

      41. Parties currently utilizing the 5 GHz spectrum generally support the 100 mW EIRP limit proposed in the NPRM. NTIA recommends adoption of the 100 mW EIRP limit in the 5.15-5.25 GHz band to provide adequate interference protection to primary operations in that band. L/Q adds that U-NII operations at any higher power would degrade the sharing capacity in that band and would greatly increase their potential to cause harmful interference to FSS operations in the band. L/Q also opposes allowing directional antenna use by U-NII devices operating in the band. It contends that though interfering signals from a directional antenna may not be received by all satellites overhead, they could certainly be received by satellites close to the horizon and, thus, FSS capacity to operate in the band could be impaired. The ARRL argues that permitting the power of U-NII operations to exceed 100 mW EIRP or permitting the use of high-gain antennas by non-spread spectrum U-NII devices would represent a significant departure from the underlying precepts of Part 15, which require unlicensed operations not to cause interference to other services. Although the ARRL opposes the operation of U-NII devices in the 5.725-5.825 GHz band, it states that if a 100 mW EIRP limit and a power spectral density limitation of 0.03 mW in any 3 kHz bandwidth were adopted, then U-NII devices should be able to share this band with incumbent operations. Finally, entities with spread spectrum interests oppose the operation of higher power, non-spread spectrum U-NII devices in the upper band on the basis that such operations could prevent existing spread spectrum devices from sharing that band.

      42. Decision. We find that the 100 mW power limit proposed in the NPRM is not sufficient to accommodate the range and scope of communications envisioned for U-NII devices. We believe that increasing the U-NII device power limits will enable these devices to provide for a variety of operations including local areas networks, campus-type settings, or as part of community networks. At the same time, we recognize the need to ensure that primary operations are adequately protected from harmful interference. In this regard, we note that the primary users and the considerations that relate to interference with their operations, vary in different parts of the spectrum we are providing for U-NII devices. Specifically, the 5.15-5.25 GHz band will be shared with MSS feeder links; the 5.25-5.35 GHz band will be shared with Government radiolocation operations; and the 5.725-5.825 GHz band will be shared with Government radiolocation, Amateur, ISM, and other Part 15 operations. Therefore, the sharing environment for U-NII devices will be different for each of these three 100 megahertz segments. We find a balance between providing sufficient power limits for U-NII devices and protecting primary operations may be struck by adopting different power levels for U-NII devices in each of the three 100 megahertz bands. This approach will provide the needed flexibility to allow U-NII proponents to design and manufacture equipment to meet a variety of communications needs while ensuring a successful spectrum sharing environment with other spectrum users.

      43. Accordingly, we will divide the 300 megahertz available to U-NII devices into three bands of 100 megahertz each and will establish the following maximum U-NII device power limits for each band: a) in the 5.15-5.25 GHz band, the maximum peak transmitter output power limit will be 50 mW with up to 6 dBi antenna gain permitted, which equates to 200 mW EIRP; b) in the 5.25-5.35 GHz band, the maximum peak transmitter output power limit will be 250 mW with up to 6 dBi antenna gain permitted, which equates to 1 W EIRP; and c) in the 5.725-5.825 GHz band, the maximum peak transmitter output power limit will be 1 W with up to 6 dBi directional antenna gain permitted, which equates to 4 W EIRP. To permit manufacturers flexibility in designing U-NII equipment, we will permit the use of higher directional antenna gain provided there is a corresponding reduction in transmitter output power of one dB for every dB that the directional antenna gain exceeds 6 dBi.

      44. In the 5.15-5.25 GHz sub-band, we believe a 50 mW peak output power with up to 6 dBi gain antenna will provide U-NII devices great flexibility in how this band is used. Specifically, these power limits will allow U-NII devices to provide a variety of short-range communications, such as those between computing devices (such as computers, servers, printers, etc.) within a very local area, such as in a room or in adjoining rooms. We also believe that restricting U-NII devices to this low power will allow U-NII devices to share this band with co- channel MSS feeder link operations. In this regard, we note that the initial European Conference of Postal and Telecommunications Administrations ("CEPT") studies conclude that HIPERLAN systems, which have technical characteristics similar to those of U-NII devices, can share this band with the MSS operations without causing harmful interference to the MSS feeder links. (See Section E "Spectrum Sharing Considerations" below.) While some commenters have argued that based on the CEPT studies that U-NII devices could operate at higher powers than we are adopting without causing interference, we recognize that since the CEPT study was made Globalstar has changed some of the parameters of its system and that its MSS feeder links potentially could be more susceptible to interference. In any event, we believe the power we are adopting is appropriate to ensure that U-NII devices do not cause harmful interference to MSS feeder link operations. We are also restricting U-NII use of this band to indoor operations. This will provide additional protection to co-channel MSS operations due to the attenuation of U-NII device signals as they pass through the walls and ceilings of buildings. Accordingly, we believe this power limit, along with the restriction on outdoor operations, will provide the desired balance of providing sufficient power for U-NII devices in this band, high frequency reuse, great flexibility in the types of U-NII operations that are accommodated in this band, and protection of co-channel MSS operations.

      45. In the 5.25-5.35 GHz sub-band, we are adopting a higher maximum peak transmitter input power limit of 250 mW, along with the associated higher power spectral density limit noted below. We are not restricting U-NII devices to indoor operations in this band because it will not be shared with MSS operations. We believe that U-NII operations with a peak transmitter output power of up to 250 mW and a directional antenna with up to 6 dBi of gain will be sufficient to accommodate communications within and between buildings, such as are envisioned for campus-type LANs. The only operations in this band are Government radiolocation systems (radar), and NTIA has supported allowing higher power for U-NII operations in this portion of the band. These power and antenna gain limits are comparable to the 1 W EIRP limit used for HIPERLAN and therefore should provide manufacturers with economies of scale in developing equipment useable in both the domestic and international markets.

      46. In the 5.725-5.825 GHz band, we note that spread spectrum Part 15 devices are already authorized to operate with 1 W transmitter peak output power and with up to 6 dBi gain transmitting antennas. Accordingly, we are authorizing similar peak power and antenna gain parameters for U-NII devices in this band. We believe that U-NII operations that comply with this power limit will be able to provide community networks with a typical range of several kilometers. Further, we believe that longer-range communications could be possible in areas with a low interference environment (i.e., rural areas) where high gain receive antennas could be used. (Such antennas do not affect the transmitted emission level or EIRP.) We recognize that the commenters recommend that we allow the use of even higher gain transmitting antennas in this band. However, the record in this proceeding does not provide enough technical support for us to conclude that U-NII devices with 1 W transmitter power and high gain transmit antennas would not cause interference to the primary service, Government radiolocation. Specifically, NTIA has expressed concern about higher powers in this band and supports further experimentation before either higher power or gain is authorized.

      47. In ET Docket No. 96-8, we are currently considering whether to authorize the use of transmitting antennas with higher gain for Part 15 spread spectrum operations in this band. If we decide in that proceeding to permit the use of higher antenna gain for spread spectrum operations, we may consider similar action for U-NII devices in this band in a separate rule making. However, we note that permitting use of high gain antennas with U-NII devices without requiring an equal reduction in power could have a significant impact on the interference environment in this band, and this issue would have to be addressed should a further rule making be initiated.

      48. With regard to sharing this band with amateur operations, we believe that U-NII devices will cause little interference to amateur operations because of the relatively low power with which U-NII devices will operate. Further, we note that the amateur service has access to all spectrum within the 5.65-5.925 GHz range. We therefore believe that amateur operations will be able to avoid using frequencies within the 5.725-5.825 GHz band that are available to U-NII devices, in those rare cases where such avoidance may be necessary.

      49. Additionally, in all three bands we are adopting peak power spectral density limits to ensure that the power transmitted by U-NII devices is evenly spread over the emission bandwidth. Specifically, we will require U-NII devices to decrease transmitter output power proportionally to any decrease in emission bandwidth below 20 MHz. These requirements will decrease the potential for interference to other services and will encourage the use of the U-NII bands for the broadband operations for which they are intended. For U-NII devices operating with less than 20 megahertz of emission bandwidth, we will limit power spectral density as follows: a) in the 5.15-5.25 GHz band, the transmitter peak power spectral density will be 2.5 mW/MHz for an antenna gain of 6 dBi; b) in the 5.25-5.35 GHz band, the transmitter peak power spectral density will be 12.5 mW/MHz for an antenna gain of 6 dBi; and c) in the 5.725-5.825 GHz band, the transmitter peak power spectral density will be 50 mW/MHz for an antenna gain of 6 dBi. Finally, to allow manufacturers flexibility in designing U-NII devices, we will allow operations with antenna gains exceeding 6 dBi if the peak power spectral density is reduced by the same amount the directional antenna gain exceeds 6 dBi.

      50. In the 5.15-5.25 GHz band, we will require transmitting antennas to be an integral part of the U-NII device. This will ensure that our authorized power limits are not exceeded in this band. In the 5.25-5.35 GHz and 5.725-5.825 GHz bands, we shall require that the U-NII device use a permanently attached antenna or an antenna that uses a unique coupling to the U-NII devices in accordance with Section 15.203(a) of the rules. These requirements will limit potential interference to other systems and will provide for greater frequency reuse by U-NII devices.

3.    Emissions Outside the Band of Operation

      51. In the NPRM, we proposed to require that all emissions from U-NII devices occurring outside of the U-NII bands be attenuated by at least 50 dB or to the radiated emission limits set forth in Section 15.209, whichever is the lesser attenuation. In addition, we proposed that any emissions occurring in the restricted bands comply with the radiated emission limits set forth in Section 15.209. We also proposed to amend Section 15.205 to delete 5.15 - 5.25 GHz as a restricted band. Further, we proposed to require that any unwanted emissions comply with the general field strength limits set forth in Section 15.209. Finally, for any U-NII devices that use an AC power line, we proposed to require such devices to comply also with the conducted limits set forth in Section 15.207.

      52. Comments. Only a few parties commented on the emission limits proposed in the NPRM. Several commenters supported the proposal. For example, Mulcay agrees with the proposal to limit emissions pursuant to Section 15.209. However, other commenters argue that the Commission should permit industry to develop limits on emissions that fall outside the bands of operation. WINForum supports reliance on emission limits and measurement methods that would be developed by industry and argues that the rules regarding unwanted emissions should be stated in terms of burst average power and should be independent of the power of the fundamental emission.

      53. Decision. Limits on emission levels outside the bands of operation and frequency stability requirements are necessary to protect adjacent spectrum occupants and sensitive operations that may operate on harmonic frequencies. However, in view of the higher and different power limits we are adopting for U-NII devices in each of these bands, we are making appropriate adjustments to the limits we proposed in the NPRM on the permissible emission levels outside the band. Specifically, we will require U-NII devices operating in the upper band to attenuate emissions below the maximum power spectral density by a factor of at least 40 dB for frequencies from the band edge to 10 megahertz from the band edge and by a factor of at least 50 dB for frequencies greater than 10 megahertz from the band edge. For the other two bands which have lower maximum power limits we will take this limit as an absolute limit. This will provide the same level of interference protection outside all three bands. Accordingly, the attenuation of peak levels of emissions outside of the frequency bands of operation below the maximum peak power spectral density contained within the bands of operation must be in accordance with the following limits:

i) For transmitters operating in the band 5.15-5.25 GHz: all emissions within the frequency range 5.14-5.15 GHz and 5.35-5.36 GHz must be attenuated by a factor of at least 27 dB; within the frequency range outside these bands by a factor of at least 37 dB.

ii) For transmitters operating in the 5.25-5.35 GHz band: all emissions within the frequency range from the band edge to 10 MHz above or below the band edge must be attenuated by a factor of at least 34 dB; for frequencies 10 MHz or greater above or below the band edge by a factor of at least 44 dB.

iii) For transmitters operating in the 5.725-5.825 GHz band: all emissions within the frequency range from the band edge to 10 MHz above or below the band edge must be attenuated by a factor of at least 40 dB; for frequencies 10 MHz or greater above or below the band edge by a factor of at least 50 dB.
As already specified in the rules, the measurements of such emissions shall be performed using a minimum resolution bandwidth of 1 MHz. Regardless of the attenuation levels shown above, we will not require emissions outside the frequency range of operation to be attenuated below the general radiated emission limits in Section 15.209 of our rules. Further, we will not specify these emission limits as a maximum power spectral density of the operating band, as requested by WINForum, because such a limit would have to be adjusted with changes in antenna gain in order to maintain a consistent interference potential. The emission limits being adopted are based on the peak power spectral density within the band of operation, and the power spectral density is varied to reflect changes in the gain of the antenna. We recognize that changes to the gain of the antenna at harmonic frequencies may not directly correlate with changes to the antenna gain at the fundamental frequency. However, we believe that the limits being adopted for spurious emissions are sufficient to reduce the probability of harmful interference. Further, the provisions in Section 15.205 of our rules will ensure that harmful interference does not result to critical safety services regardless of antenna gain.

      54. Further, we will adopt our proposal to remove the 5.15-5.25 GHz band from the restricted bands listed at Section 15.205 of the rules. We note that U-NII devices will have to comply with the provisions of Section 15.205 in order to protect sensitive operations. We also note that the 4.5-5.15 GHz and 5.35-5.46 GHz bands remain restricted; therefore, U-NII devices operating close to the band edges at 5.15 GHz or 5.35 GHz will be required to sharply attenuate their signal at the band edge or avoid using the spectrum close to the band edge. We do not believe that this requirement will significantly affect U-NII operations overall. In any event, this requirement is needed to protect sensitive and safety-of-life operations in adjacent bands. Additionally, we adopt our proposal to require that emissions comply with the general field strength limits set forth in Section 15.209. Finally, any U-NII devices that use an AC power line must comply with the conducted limits set forth in Section 15.207.

4.    Channeling Plan & Modulation Efficiency

      55. In the NPRM, we did not propose to adopt limits on channelization or modulation efficiency, but did request comment on whether we should specify a channeling plan or a minimum modulation efficiency requirement for U-NII devices to ensure efficient use of the spectrum. We specifically requested comments on whether a 20 or 25 MHz channeling plan and/or a 1 bit/second/Hz ("bps/Hz") modulation efficiency should be adopted and whether these regulations would be beneficial in facilitating unlicensed broadband high data rate use of these bands.

      56. Comments. Commenting parties disagree as to whether the Commission should adopt a mandatory channelization plan or minimum bandwidth requirement for unlicensed U-NII devices. Those supporting a channelization plan and/or minimum bandwidth requirement argue that the 5 GHz unlicensed bands should be dedicated for wideband systems. These parties contend that other unlicensed bands such as the U-PCS spectrum are already available for narrower bandwidth applications. They claim that some channel limitations are needed. They contend that wideband devices with high signaling speed requirements suffer disproportionately from harmful interference caused by narrow bandwidth devices with low signaling speed requirements, and that complex rules would be required to correct this imbalance. WINForum, Lucent, and Nortel support a minimum channel spacing of 20-25 megahertz and suggest that the rules not prohibit U-NII devices from combining channels to enable very wide bandwidth communications. In addition, Nortel states that a 20-25 megahertz minimum channel bandwidth would simplify any industry-developed access protocol by limiting the number of channels that would need to be scanned in order to detect the absence of communications from other devices before transmitting. Further, it notes that such a channeling plan would enable U- NII devices to be compatible with HIPERLAN equipment.

      57. On the other hand, several NII proponents argue that, with so many open questions about the future needs for unlicensed wireless networking capabilities, it is premature and technically unwise to specify a channeling plan or a maximum channel bandwidth. The channelization for these bands should be flexible, they state, because the bandwidth required for a given application is dependent on the data rate, communications distance, type of modulation, and specific error correction coding involved. They also claim that a minimum channel width or channelization requirement may limit both technical innovation and flexibility and therefore may increase costs and retard development of new communications options. Finally, although Apple opposes mandatory channelization standards, it states that, in the bands used for high data rate systems, voluntary channelization plans or more informal channelization etiquettes could be developed by industry to promote efficient spectrum use.

      58. Most U-NII proponents oppose the imposition of any requirement for modulation efficiency. They claim that such a requirement would increase system complexity and preclude certain modulation techniques, which would in turn increase costs and development time, and delay implementation of U-NII devices. Several commenters oppose the 1 bps/Hz modulation efficiency suggested in the NPRM on the grounds that it would preclude spectrum efficient technologies such as spread spectrum, which they observe is spectrally efficient because of its high interference rejection and spectral reuse but may not meet a 1 bps/Hz requirement. Further, several parties claim that efficiency can only be measured meaningfully when geographic frequency re-use (cell area) is also considered, such as bps/Hz/unit-area. These parties argue that a robust system with low modulation efficiency that is capable of operating in the presence of higher potential interference may nevertheless have higher throughput per unit area than a less robust system. Finally, they argue that it is unnecessary to mandate a standard for spectrum efficiency, since the market will decide what efficiency is needed. In this regard, WINForum recommends forgoing the adoption of a modulation efficiency standard at this time in favor of allowing industry groups to consider the development of a more flexible spectral efficiency measure that would take into account frequency reuse characteristics.

      59. A few U-NII proponents do support adoption of a modulation efficiency standard. For example, Hewlett-Packard Company ("Hewlett-Packard") recommends a minimum modulation efficiency standard of 0.66 bps/Hz, arguing that, though specification of a high bandwidth efficiency does not guarantee a high spectral efficiency, it can nevertheless prevent low transmission rate systems from using the spectrum inefficiently. Lucent recommends a minimum modulation efficiency standard of 0.5 bps/Hz based on the use of a 3-dB bandwidth, as opposed to use of the full emission bandwidth. If, however, the emission bandwidth were used, Lucent recommends a higher minimum modulation efficiency standard. NTIA also recommends adoption of a bandwidth efficiency standard, but claims that imposition of a strict efficiency limitation at the outset may dampen rapid implementation. Therefore, NTIA recommends that the Commission adopt an effective bandwidth efficiency standard that would come into effect at some reasonable future date, such as three years after conclusion of this rule making proceeding.

      60. Finally, some parties, particularly incumbents, argue that a modulation efficiency standard should be required in order to ensure that spectrum is not wasted. They state that highly efficient technologies currently exist and that it is not unreasonable to require U-NII devices to have modulation efficiencies higher than 1 bps/Hz. Alstatt Associates, for example, argues that, since digital television set-top boxes have a modulation efficiency of 6.66 bps/Hz, and Part 21 and 94 devices have a minimum modulation efficiency of 4.46 bps/Hz, U-NII devices should be required to have a minimum efficiency of 3 bps/Hz. Larus Corporation ("Larus") agrees that we should adopt a modulation efficiency standard of no less than 3 bps/Hz, while the Northern Amateur Relay Council of California, Inc. ("NARCC") argues that a spectrum efficiency of 2 bps/Hz is appropriate and has in fact been achieved for years.

      61. Decision. One of our goals in this proceeding is to provide rules which permit maximum technical flexibility in the design and development of U-NII devices capable of providing high data rate communications for a variety of multimedia applications in a shared spectrum environment. Such devices have not yet been designed, built, or tested. Accordingly, we believe that adopting a rigid channelization plan or mandating a modulation efficiency standard at this time would not meet this goal, and could delay implementation of U-NII devices by precluding certain technologies or applications. Further, we believe that the low power limits we are adopting will ensure efficient use of the spectrum by providing for high frequency reuse, which will allow for large numbers of U-NII devices to share the spectrum in any geographic area. We also believe that establishing a channelization plan or modulation efficiency at this early stage in the technological development of the devices might have several undesirable effects, such as increasing costs and delaying the benefits of U-NII devices to the public. Accordingly, we will not adopt a channeling plan or a modulation efficiency standard at this time.

      62. Nevertheless, we note that the focus of this proceeding is to make available spectrum for broadband high data rate unlicensed devices capable of meeting the communications requirements of new multimedia applications. We therefore agree with those commenting parties that suggest the purpose of making these bands available is to support use of high data rate devices. Accordingly, we are adopting a definition for the type of devices that will be approved for this band. Specifically, the Part 15 rules will state that unlicensed U-NII operations in the 5.15-5.35 GHz and 5.725-5.825 GHz bands will be limited to wide bandwidth, high data rate digital operations. Unlicensed devices accessing the 5.725-5.825 GHz band under other Part 15 rules would not be subject to this definition. This will give equipment manufacturers the flexibility to design and manufacture a variety of broadband devices using different technologies and modulation techniques, while ensuring that this spectrum is used for its intended purpose. This definition will be enforced through the Commission's equipment certification process.

D.     Spectrum Etiquette

      63. In the NPRM, we proposed a basic "listen-before-talk" ("LBT") spectrum sharing etiquette, similar to that established for U-PCS devices, to ensure that the U-NII spectrum is used by devices in a manner that would permit them to share with one another. We suggested that the proposed etiquette could serve as an interim protocol standard until industry developed a spectrum sharing etiquette. In this regard, the NPRM encouraged industry to develop appropriate etiquette protocols for these devices through a consensus process and stated that, if appropriate, we would consider those protocols in this or a further rule making proceeding. Finally, we solicited comments on whether such an etiquette should be required at all, or whether the minimal technical requirements would be sufficient to ensure spectrum sharing among U-NII devices.

      64. Comments. The commenters overwhelmingly oppose the LBT spectrum etiquette proposed in the NPRM for U-NII devices. Several parties argue that the LBT protocol is unnecessary and would be detrimental to U-NII devices at 5 GHz. For example, Motorola states that LBT would be ineffective in controlling interference among U-NII devices, particularly in buildings with many rooms and hallways. Several commenters also assert that LBT would be detrimental because it would preclude isochronous multimedia applications and other technologies such as Asynchronous Transfer Mode ("ATM") that would not be able to comply with strict transmission time-frame requirements. Motorola claims that LBT would unduly restrict the utilitarian choices which manufacturers of U-NII devices could offer to consumers.

      65. Additionally, some commenters oppose establishing any interim etiquette on the grounds that devices developed under such an interim etiquette could be rendered useless once a permanent etiquette is adopted. In this regard, Lucent asserts that adoption of an interim etiquette would hinder introduction of future systems and would inhibit the process of developing an industry consensus for spectrum sharing rules. Cylink contends that interim rules would harm the competitiveness of small businesses. It claims that only larger companies could afford to cover the risk of betting on the eventual outcome of industry working group deliberations aimed at adopting a consensual etiquette. Similarly, WINForum expresses concerns about the compatibility of interim devices with any subsequent permanent spectrum etiquette and suggests that any interim operations should be constrained to 50 megahertz in the upper band with a date-certain changeover mandate.

      66. Several commenters, while not supporting the proposed LBT etiquette, do support the development of a spectrum etiquette, or of multiple etiquettes, by industry consensus in order to help minimize interference among U-NII devices. For example, WINForum states that high-level protocols, like that adopted for U-PCS, may be excessively complex for U-NII devices, but simple RF rules (e.g., power limits, channelization, unwanted emission limits) may prove insufficient to ensure fair, efficient, and open access. It adds that the development of such standards is appropriately left to voluntary standards organizations. NTIA also supports some type of channel monitoring protocol or U-NII etiquette to minimize interference, both to and from radar systems. Further, several other commenters aver that industry should be permitted to develop etiquettes within a time frame mandated by the Commission.

      67. Some commenters oppose the adoption of any spectrum etiquette, stating that a required etiquette would inevitably limit innovation in the development of new U-NII products, and that the use of etiquettes has not always been proven to avoid interference. The Connectivity for Learning Coalition ("Coalition") asserts that while such protocols mandate a manner in which some technologies may share the spectrum, use of those technologies may or may not meet the needs of the education or library communities. Metricom, Inc. ("Metricom") states that, in theory, an etiquette may appear to allow for spectrum sharing, but there is no practical evidence that complex etiquettes prevent interference. Metricom states that creative engineers guided by minimal technical standards will best be able to design communications solutions to match consumer needs. Finally, 3Com Corporation ("3Com") claims that a formal spectrum etiquette would limit ingenuity and development of U-NII devices, and it urges the Commission to encourage the development of voluntary spectrum etiquettes to permit interoperability.

      68. Decision. In general, we believe that a spectrum etiquette can provide benefits by facilitating compatibility among devices and allowing for equal access to the spectrum by devices that use different technologies. However, we do not believe that the interim LBT etiquette proposed in the NPRM would provide such benefits for unlicensed U-NII devices in the 5 GHz band. As pointed out in the comments, that LBT etiquette would be ineffective in controlling interference among devices and would preclude some technologies that may be desirable for U-NII devices. Accordingly we will not adopt our proposed etiquette.

      69. We also note that the record does not provide an alternative spectrum etiquette to our proposed LBT etiquette that we could adopt at this time. Additionally, we do not think that it would be in the public interest to wait for an industry group to develop a satisfactory new etiquette as suggested by WINForum. We are concerned that it could take industry a substantial period of time to develop an etiquette for unlicensed U-NII devices at 5 GHz, because of the wide range of interests that would have to be accommodated in establishing a single etiquette for all the broad multimedia applications envisioned for U-NII devices. Further, after such an etiquette is developed, we would have to conduct a rule making proceeding to adopt the etiquette as a mandatory standard. Completing these activities would take at least a year, and possibly considerably longer. We do not believe that such a delay in implementing rules permitting U-NII operations would serve the public interest.

      70. We recognize that there are trade-offs in adopting any etiquette and that the benefits of an etiquette must be weighed against its drawbacks. For example, an etiquette could beneficially facilitate compatibility among devices and thus promote spectrum sharing, inter- communications among different devices, and equal access to the spectrum by devices built by various manufacturers. Drawbacks of an etiquette include an increase in the complexity of equipment design and, hence, an increase in cost to the manufacturer and the user, as well as a potential limitation on access to the spectrum by some technologies and equipment. In the instant case, it is early in the developmental stage for equipment to operate in these shared bands as intended. Therefore it may be very difficult to develop a spectrum etiquette at this time that will not limit the types of equipment that could most efficiently or effectively provide the desired broadband communications.

      71. Accordingly, we are not adopting a spectrum sharing etiquette at this time, nor will we delay access to the 5 GHz bands by U-NII devices until industry develops an etiquette. We believe the minimal technical rules we are adopting, particularly the maximum power limits discussed above, will generally allow for equal access and sharing of these bands by U-NII devices and thereby accomplish the intent of our proposed spectrum etiquette. Finally, our course of action will not preclude industry from developing any voluntary standards that it deems appropriate in the future. In this regard, we continue to encourage industry to develop appropriate etiquette protocols through a cooperative consensus process. If standards are developed that would better facilitate sharing of this band without precluding U-NII devices or technologies, we would consider adopting those protocols in a further rule making proceeding. We note that WINForum states that it has already begun setting the foundation for joint industry action in this area. We encourage all interested parties to take part in this process and to cooperate in good faith.

E.     Spectrum Sharing Considerations       72. In the NPRM, we recognized that a number of primary services now use, or soon will use, the spectrum which we proposed for U-NII devices. The existing operations include Government radiolocation systems; mobile satellite feeder links; amateur operations; industrial, scientific, and medical operations; other unlicensed Part 15 operations; and proposed ITS. We stated in the NPRM that it would be necessary to develop spectrum sharing criteria between primary operations and the new U-NII devices. We tentatively concluded in the NPRM that sharing would be feasible, but requested comments on this issue.

      73. Comments. NTIA, the Government agency responsible for the spectrum management for Government operations, supports our proposal to permit U-NII devices to share these bands with primary Government operations. However, NTIA urges us to adopt sharing protocols and power limitations to facilitate sharing. NTIA states that the success of community networks will depend on their geographic separation from high powered radar systems operating in these bands. NTIA adds that Federal radar systems serve the interests of national security and that, therefore, all efforts should be made to avoid operating community network links near military radar sites. Additionally, NTIA states that compatibility analyses of long range links with existing radar needs to be completed for both U-NII and spread spectrum systems before higher powers are authorized.

      74. In the 5.15-5.25 GHz band, parties with MSS interests argue that sharing is not feasible between MSS feeder links and new U-NII devices. In particular, L/Q asserts that only 1070 simultaneous users of U-NII devices could operate in the 5.15-5.25 GHz segment in the continental United States before unacceptable interference would be caused to the feeder links for Globalstar, its proposed mobile satellite system. Airtouch Communications, Inc. ("Airtouch"), a limited partner in Globalstar, claims that its analysis indicates that U-NII operations in the 5.15-5.25 GHz band would reduce the capacity of Globalstar in the U.S. by over 27%. Further, Airtouch and L/Q argue that the European sharing analysis for HIPERLAN, addressed in the NPRM, cannot be applied in this proceeding because U-NII devices and HIPERLAN do not have similar technical parameters and the International Telecommunication Union ("ITU") analysis is not based on current data.

      75. On the other hand, U-NII proponents claim that U-NII devices would be able to share with Government radiolocation and MSS feeder uplinks operations because of the very low power with which U-NII devices will operate in the 5.15-5.25 GHz band and because of the attenuation characteristics of radio signals in the 5 GHz range. With regard to sharing with MSS feeder uplink operations, they conclude that MSS feeder operations would also be able to share with U-NII devices. They base this conclusion on the ITU study, which predicted that HIPERLAN systems would be able to co-exist with the MSS feeder links in the 5.15-5.25 GHz band in Europe. Further, they note that HIPERLAN devices will be operating at 1 W, a power level substantially higher than the power limit proposed for U-NII devices in this band, and that global MSS systems must be built to be robust enough to share with HIPERLAN. WINForum and Solectek Corporation ("Solectek") also counter L/Q's claim that only 1070 U-NII devices could use the band in the United States before causing interference to MSS feeder links, pointing out that L/Q made strict assumptions that are not representative of the U-NII device environment. Specifically, WINForum notes that ITU's studies assume a more reasonable performance margin of 0.41 dB rather than the 0.004 dB that L/Q used. Based upon these more realistic criteria, WINForum claims that over 540 million U-NII devices could be deployed in the United States without causing harmful interference to the FSS uplink systems.

      76. Additionally, some parties argue that use of directional antennas will decrease the radiation perceived by a satellite above the users in the vertical plane. Further, Lace, Inc. ("Lace") argues that a 10% power increase in the MSS feeder link would easily resolve the interference problem, if indeed that problem ever occurs. Lace and Solectek argue that there are other means to mitigate interference such as power spectral density limits, transmitter on-time limits, station antenna directivity, relay link antenna directivity, out-of-band noise rejection, and positioning long range outdoor links above 5.25 GHz.

      77. In the 5.725-5.825 GHz band, incumbent operators either oppose allowing U-NII operation due to interference concerns or urge that sharing studies be completed before that band is made available to U-NII devices. For example, the San Bernardino Microwave Society ("SBMS") argues that sharing between U-NII devices and amateur operations is not possible. However, the ARRL states that the proposed U-NII maximum power limit of 100 mW EIRP appears to be sufficient to avoid significant interference to the amateur service, but it argues that the ubiquitous nature, mobility, and potential aggregate interference potential of these devices necessitates that sharing studies be performed. Additionally, Section 15.247 spread spectrum interests oppose U-NII operations in this band and argue that without a means to control usage, operations in this band would rapidly degrade and become unusable. Further, incumbents oppose high power U-NII operations in this band because they argue it is more likely to cause interference to incumbent operations. The ARRL also claims that higher power U-NII operations should not be permitted because the Commission is unlikely to enforce the requirement that unlicensed device users cease operation if they are causing harmful interference to allocated services. Finally, Metricom states that to avoid interference, U-NII devices in the upper band should be required to operate in spread spectrum mode.

      78. On the other hand, U-NII proponents argue that U-NII devices can share with Government radiolocation, amateur operations, ISM devices, other Part 15 devices and proposed ITS operations. They argue that these incumbent operations already share this band with other types of unlicensed devices. In this regard, Mulcay notes that a substantial number of devices, including Part 15 direct sequence spread spectrum radios with 1 W output power and antenna gains of 30 dBi, frequency hopping radios with omni-directional antennas and non- communication devices under Part 18 with no limit on radiated power, already share the 2.4 and 5.8 GHz bands on an unlicensed, non-coordinated basis without causing interference. WINForum likewise argues that U-NII devices operating under equivalent technical standards can also share this band without causing harmful interference. Apple notes that U-NII devices will only share a part of the 275 megahertz wide amateur band at 5.65-5.925 GHz and, therefore, claim that U-NII operations will not significantly affect the amateur radio service. With regard to sharing with other Part 15 devices, U-NII proponents contend that the record demonstrates that U-NII devices can be designed to coexist with spread spectrum devices. CEMA argues that industry can develop technical guidelines and methodologies to allow community network systems and other systems to share unlicensed bands. Further, Apple claims that directional antennas will reduce the probability that multiple devices will compete for spectrum in overlapping areas.
      79. Decision. We continue to believe that U-NII devices can share these bands with existing and future operations. Specifically, we believe that the power limits, power spectral density requirements and emission limits that we are adopting herein will permit the robust development of U-NII devices without a significant impact on other spectrum users. With regard to Government operations, we agree with NTIA that MLS operations below 5.15 GHz must be protected. Accordingly, we are not allowing U-NII devices access to spectrum below 5.15 GHz. We believe that this decision, along with the power limits and out-of-band emission limits, will adequately protect MLS operations. We also agree with NTIA that co-channel sharing with Government radiolocation is possible. We believe the power limits we are adopting will allow for this sharing as detailed below. Further, we believe that there will be no interference from U-NII devices to possible ITS operations, since we are not allowing U-NII devices access to the 5.85-5.875 GHz band.

      80. In the 5.15-5.25 GHz band, we note that the sharing analyses completed to date often reach different results because they are based on different assumptions. For example, since the CEPT studies were made, Globalstar has changed some of the parameters of its system, and, therefore, MSS feeder links potentially could be more susceptible to interference than those studies concluded. Based upon the information before us, we conclude that the limits we are adopting will ensure that U-NII devices do not cause harmful interference to MSS feeder link operations.

      81. In the 5.25-5.35 GHz band, we believe that the 1 W EIRP limit and the power spectral density requirements we are adopting for U-NII devices will adequately protect the primary radiolocation operations. We note that Government radiolocation systems are limited in number and generally located at remote military sites, on board ships, in aircraft and in spacecraft, and that these considerations in conjunction with the U-NII power limits should adequately protect the radiolocation service. Further, U-NII devices will have to accept interference from the radiolocation service.

      82. In the 5.725-5.825 GHz band, we believe that the 4 W EIRP limit and the power spectral density requirements we are adopting for U-NII devices will adequately protect the primary radiolocation operations and amateur operations. These limits provide U-NII devices with power levels equivalent to Part 15 spread spectrum devices that already share this band with incumbent services. Therefore, U-NII devices should likewise be able to share this band without causing interference to the primary services. Further, with regard to spectrum sharing with the amateur service, we note that the amateur service has access to 275 megahertz of spectrum in the 5.65-5.925 GHz band. We believe amateur licensees will, if necessary, be able to operate around U-NII devices, which only have access to 100 megahertz in this portion of the 5 GHz spectrum. Additionally, we note that we are not at this time providing spectrum above 5.825 GHz for U-NII devices. This eliminates any sharing concerns with users or potential users of the 5.825-5.875 GHz band, which includes lower power Part 15 devices such as hearing aid devices, as well as ITS operations, and FSS operations.

      83. We also believe our power spectral density requirements will permit U-NII devices to share this spectrum with unlicensed spread spectrum devices as the potential for interference to these devices from new U-NII devices will be no greater than that which would be expected from additional spread spectrum devices. Thus we see no reason to restrict U-NII devices in this band to spread spectrum technologies as requested by some commenters. Accordingly, we will allow U-NII devices in this band to operate on a technology-neutral basis. We believe this will provide manufacturers flexibility in designing U-NII products and thus will provide consumers with greater choices.

F.     Alternative Regulatory Structure

      84. In the NPRM, we proposed to allow U-NII devices to operate on an unlicensed basis. We tentatively concluded that the low power and limited range of U-NII devices would make licensing administratively difficult for users and the Commission. Further, we noted that this spectrum may be of very limited use to licensed services due to the presence of incumbent operations. Nonetheless, we requested comment on whether new U-NII operations should be provided on a licensed basis. We also solicited comments with regard to whether we should license higher power community networks if we were to allow such operations. We also asked whether, in the case of mutually-exclusive applications, we should use competitive bidding to award such licenses.

      85. Comments. Most U-NII proponents support our proposal to allow U-NII devices to operate on an unlicensed basis. They oppose licensing and auctions of any U-NII operations, arguing that the benefits of authorizing Part 15 devices and systems would be undermined completely if licensing were required. They state that licensing -- even expedited licensing -- would impede deployment, reduce innovation, reduce spectrum efficiency, increase costs, undermine the development of community networking and deny the benefits of low cost and flexible alternatives to existing media. Apple also contends that unlicensed community networks would not create problems of regulatory parity for common carriers and other profit making service providers. It states that those electing to use unlicensed bands would accept the fact that they will not control their spectrum environment and will be limited to low power operations; in exchange, they would be freed from the costs and burdens associated with licensing.

      86. However, AT&T, PacTel, TIA and some microwave equipment manufacturers state that if the Commission permits the operation of longer range community networks, those networks should be subject to licensing and auctions. AT&T states that allowing unlicensed community networks would be unfair to the holders of existing spectrum licenses, particularly those who received their licenses through the auction process, and would undermine the Congressional objective of promoting regulatory parity among wireless services. AT&T further states that the type of operation envisioned for community networks requires a degree of reliability and quality that can only be realized through licensed services. PacTel argues that unlicensed community networks would create an inequitable regulatory structure where unlicensed service providers operate in competition with licensed service providers without the common carrier obligations of a licensee. TIA states that implementing long range networks requires frequency coordination, use of narrow beam antennas and other fundamental components of licensing in order to succeed.

      87. Decision. We continue to believe that low power U-NII devices and associated operations are more amenable to an unlicensed structure and should be regulated under the Part 15 rules. Specifically, the rules governing U-NII devices are similar in their low power and flexible regulatory nature to those governing Part 15 devices. While some U-NII devices in the upper band could have ranges of several kilometers, we believe that most devices will have typical communication ranges of a few meters to a few hundred meters. Additionally, like other existing unlicensed devices, we believe that trying to license U-NII devices individually would be administratively difficult if not impossible for both the Commission and the consumer and would greatly delay the implementation and use of this band by U-NII devices. Further, we do not think it would be advisable at this time to license spectrum blocks and large service areas to providers.

      88. We also are unpersuaded by the arguments that U-NII devices and associated operations need to be licensed in order to provide regulatory parity with licensed services. With regard to unlicensed U-NII devices that are used for community networks in the upper band, we note that these will also be of very limited range in comparison to the distances of fixed point-to- point operations, will have to operate in a Part 15 sufferance mode and may not always be able to provide the same grade of service as the licensed operations. That is, they will receive no protection from other users of the spectrum. Further, we note that in the upper band unlicensed devices are already providing point-to-point links for data transmissions, typically of up to 1.5 Mbits/sec. Further, we believe that the vast majority of U-NII devices will provide communications that are complementary to, rather than competitive with, the licensed services. We believe that the relationship between U-NII devices and the licensed point-to-point services will be analogous to the relationship between cordless telephones and PCS or the cellular telephone service. That is, U-NII devices will provide a variety of broadband high data rate services but only in a very limited range and generally on the premises of the users, while licensed fixed point-to-point microwave services provide communication links that are substantially longer, up to 30 and 40 miles, and in a controlled radio environment where the licensee has the right of protection from interference.

      89. We do believe, however, that this proceeding has raised a number of spectrum issues that warrant further attention. Users and manufacturers of unlicensed devices, for example, may have little incentive to make the investment necessary to improve spectrum efficiency and thus allow more users to benefit. As we continue to implement spectrum policies that promote competition and efficiency we may also need to consider how to harmonize these policies with those for unlicensed devices.

G.     New Part 16 Regulations

      90. In the NPRM, we tentatively concluded that the technical and operational flexibility afforded under Part 15 is the appropriate structure for regulating U-NII devices, rather than a new Part 16 regulatory scheme. Under the Part 16 concept, unlicensed devices could be treated as a recognized radio service with spectrum rights, including interference protection. Alternatively, we proposed to establish a "safe harbor" or clear technical operating parameters under which users of unlicensed U-NII devices could operate without being considered sources of harmful interference. Consistent with Part 15 operations, we also proposed that U-NII devices have to accept any interference.

      91. Comments. NII proponents support the principles underlying either "safe harbor" or the Part 16 approach. Apple argues that for U-NII devices to become viable, these devices must be treated as a recognized radio service, and their operations must be in protected spectrum reflected in Section 2.106 of the rules, the Table of Frequency Allocations. Further, Apple states that the Commission should make clear that it will not introduce new, incompatible services into the NII bands in the future. Apple argues this is fully consistent with both the Communications Act and Commission precedent; in that, it is identical to the approach adopted for unlicensed-PCS and millimeter wave bands. Further, Apple argues that this approach is consistent with the Commission's obligation under Section 303(g) of the Communications Act to 'study new uses for radio... and generally encourage the larger and more effective use of radio in the public interest.' CEMA also argues that the Commission has the authority to elevate the status of unlicensed devices and suggests upgrading the status of U-NII devices to co-primary within the allocated bands. It claims that otherwise these devices will remain, by regulatory design, second class citizens in the RF environment. Further, WINForum claims that some rural and educational users may not be willing to risk investment in equipment absent some reassurance that their communication needs will be met now and in the future. Finally, Cylink, Metricom and existing unlicensed spread spectrum device providers argue that if additional protection is provided to unlicensed U-NII devices in this range of the spectrum, then this protection also should be extend to unlicensed spread spectrum devices.

      92. However, Airtouch and other parties with interests in the 5.15-5.35 GHz and 5.725-5.825 GHz bands state that the "safe harbor" concept conflicts with the Part 15 regulatory scheme and would relieve unlicensed users of their obligation to avoid interference to licensed users. L/Q argues that an analogy cannot be made to the protection provided to unlicensed Data-PCS devices because unlicensed Data-PCS devices received an allocation of exclusive spectrum, but U-NII devices will not operate on exclusive spectrum. SBMS and other amateur interests oppose "safe harbor" rules because there will be no means of enforcement to prevent U- NII devices from causing interference.

      93. Decision. We generally have provided spectrum for low power unlicensed devices on a non-interference basis, meaning that unlicensed devices must not cause interference to licensed users and must accept any interference they receive. This regulatory approach to accommodating unlicensed devices has protected licensed use while permitting the development of a wide variety of low power unlicensed devices. While we seek to encourage the important and valuable telecommunication operations which will be provided by U-NII devices, we find that the current record does not provide a compelling reason to believe that such devices require higher or more protected status than we have provided for low power unlicensed devices in the past. Accordingly, we do not believe that it is necessary to create a new Part 16 or "safe harbor" rules to provide additional protection for U-NII devices. We therefore, as discussed below, will regulate these devices in the same manner that we regulate other low-power unlicensed devices. We do conclude, however, that some special consideration is warranted with regard to the use of unlicensed devices in the lower band, 5.15-5.25 GHz, which will be shared with MSS.

      94. In the 5.25-5.35 GHz and 5.725-5.825 GHz bands, where the radio environment is well established with mature services, we can adopt rules in Part 15 for U-NII devices in which all parties can have confidence that sharing is possible with little or no threat of interference. In both of these bands, we believe U-NII device manufacturers and users can feel confident that their operations will not cause interference to primary operations, because in the 5.25-5.35 GHz band the only party authorized to use this spectrum is Government radar operations, with which we believe low power U-NII devices can share spectrum without causing interference, and because the U-NII devices in the 5.725-5.825 GHz band will operate with powers equivalent to those of existing unlicensed operations that currently share this band without causing interference. Additionally, if interference problems did occur in these bands they would be localized and could probably be identified and resolved. In these cases we believe that the current Part 15 at sufferance rules are appropriate.

      95. We recognize that it is likely that two new uses of the 5.15-5.25 GHz band, MSS feeder link operations and U-NII devices, will be developing at the same time. In view of this fact, as indicated above, we are adopting relatively conservative operating parameters for U-NII devices. We believe that the very low power limits and indoor use restriction on unlicensed operations will ensure that millions, or even tens of millions, of U-NII devices can successfully co-exist and share the spectrum with MSS feeder links. Further, we note that interference from U-NII devices to MSS operations could potentially occur only as a result of the cumulative effect of many millions of U-NII devices and not by any single device. To the receiver on the MSS satellite, the operation of many low power U-NII devices looks like an increase in the ambient noise floor. This has the effect of decreasing the desired signal-to-noise ratio received from the higher power MSS feeder link and can ultimately reduce the capacity of or cause interference to MSS operations.

      96. While we believe that this approach for U-NII devices is technically conservative and will fully protect MSS operations, we note that MSS interests have also suggested that we limit the aggregate EIRP density of emissions from unlicensed devices on the Earth's surface to the MSS satellite to 10 dBW/MHz. They argue that MSS operations could begin to be affected when emissions from unlicensed devices approach such a level. Alternatively, they suggest that the Commission should review the technical parameters for U-NII operations in a future rule making as such a limit is approached. They state this would allow the Commission to review, for example, whether some future reduction in permitted power of U-NII devices in this band should be imposed. They state that all existing U-NII devices would be grandfathered. We concur that such an approach would provide further assurance that future potential conflicts between U-NII devices and MSS operations are taken into account and that MSS operations are protected appropriately. Accordingly, we invite MSS parties to monitor the emissions from U-NII devices in the 5.15-5.25 GHz band and, if emissions approach the 10 dBW/MHz level, to request that we initiate a rule making to reassess the use of this band. At that time the Commission could determine if future U-NII devices should be required to operate at different technical standards. In this regard, we note that it may also be appropriate to reassess the technical parameters governing U-NII devices in light of second generation MSS systems. For example, second generation MSS systems may be more sensitive and therefore more susceptible to interference from U-NII devices. On the other hand, if European HIPERLAN systems proliferate and operate at more power than U-NII devices, second generation MSS systems may of necessity be designed to be more robust and immune to interference from such devices.

      97. We believe that this approach will provide both MSS feeder link and U-NII operations with an appropriate level of protection and assurance for the continuation of their operations. While we think it unlikely that an interference situation will arise, this approach will permit us to develop regulatory solutions that will adequately protect the investments of both services, if such a situation were to develop. Accordingly, we believe that this approach will provide both the MSS community and the U-NII device manufacturers with adequate certainty concerning their operations, and we do not believe that a "Part 16" or "safe harbor" rule is necessary for U-NII devices at this time.

H.     Equipment Authorization

      98. In the NPRM, we proposed that U-NII devices would be subject to our certification requirements pursuant to Section 15.201(b), prior to marketing. Motorola recommends that we take this opportunity to streamline our equipment approval process so that all products, including U-NII devices, may be approved and provided to the public with minimal costs and delays. However, Motorola made no specific suggestion in reference to this proceeding and its comments in reference to PP Docket No. 96-17 will be considered therein. We do not believe that applying the certification process to U-NII devices will significantly delay the provision of this equipment to the public. We believe this process helps prevent non- compliant devices from interfering with other devices or services. Accordingly, we are adopting our proposal to require U-NII devices to comply with the existing certification requirements for intentional radiators under Part 15.

      99. Finally, we will require U-NII devices to comply with the RF hazard requirements set forth in Sections 1.1307(b), 1.1310, 2.1091, and 2.1093 of our rules. For purposes of these rules, all U-NII equipment will be deemed to operate in an "uncontrolled" environment. Any application for equipment certification for these devices must contain a statement confirming compliance with these requirements. Technical information showing the basis for this statement must be submitted to the Commission upon request.


      100. Accordingly, IT IS ORDERED that Part 15 of the Commission's Rules, 47 C.F.R. Part 15 IS AMENDED as set forth in the attached Appendix, effective 60 days after publication in the Federal Register. This action is taken pursuant to Sections 4(i), 303(c), 303(f), 303(g) and 303 (r) of the Communications Act of 1934, as amended, 47 U.S.C. Sections 154(i), 303(c), 303(f), 303(g) and 303(r).

      101. Regulatory Flexibility Analysis. As required by Section 603 of the Regulatory Flexibility Act ("RFA"), an Initial Regulatory Flexibility Analysis ("IRFA") was incorporated in the NPRM in this proceeding. The Commission sought written public comments on the proposals in the NPRM including on the IRFA. The Commission's Final Regulatory Flexibility Analysis ("FRFA") in this Report and Order is attached as Appendix B.

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