For several months now, WISPA and most of the major players in the WISP market, including Ubiquiti, have been working on a proposal to present to the FCC regarding out-of-band emission (OOBE) rules for the 5.7-5.8 GHz band.
The OEMs and the operators each came to the table with varying perspectives and approaches to solve the problem of how to reach a compromise with the FCC that would allow performance similar to the old 15.247 rules for point-to-point radios without causing issues for TDWR and other systems. As these diverse ideas were discussed and reviewed, the team at WISPA had the unenviable job of trying to incorporate the various positions into a single proposal.
Yesterday details of that proposal were released, and some may have noticed that Ubiquiti’s name was not on the list of manufacturers that had signed on. Although we participated in the calls and appreciate the efforts made by WISPA and other manufacturers, Ubiquiti decided to submit an alternate proposal to the FCC with what we feel would be best for WISP's and the industry. It is not our intent to contradict the WISPA proposal, but rather to provide another option for the FCC to consider.
Ubiquiti’s strategy is to pursue a simple, straight-forward, two-part compromise proposal with the FCC. The proposed changes (in bold) and a brief explanation are presented below.
"For transmitters operating in the 5.725-5.85 GHz band: All emissions within the frequency range from the band edge to 75 MHz above or below the band edge shall not exceed an e.i.r.p. of 17 dBm/MHz; for frequencies 75 MHz or greater above or below the band edge, emissions shall not exceed an e.i.r.p. of -27 dBm/MHz.”
This first change would modify the rules to take into account the technical challenges posed by the characteristic spectral shape of OFDM signals, which have regrowth components of up to 3x the 26dB bandwidth. However, this change still maintains the -27dBm/MHz emissions limits that the FCC and the FAA have already agreed to for adequate protection of the TDWR band. Finally, it also aligns the U-NII-3 OOBE with U-NII-1 OOBE rules, which allow 11dBm/MHz + 6dBi antenna = 17dBm/MHz.
2. Modify 15.407(b)(3) to read (changes in bold):
"For transmitters operating in the 5.47-5.725 GHz band: All emissions outside of the 5.47-5.850 GHz band shall not exceed an e.i.r.p. of -27 dBm/MHz.”
This change would make the verbiage consistent with the treatment of the 5250 MHz boundary between U-NII-1 and U-NII-2A in 15.407(b)(1) and (2), and would explicitly allow U-NII-2C transmitters to straddle the 5725 MHz boundary between U-NII-2C and U-NII-3.
Ubiquiti feels that these simple, minor changes will address the concerns of OEMs and operators and allow the manufacture and deployment of economically priced radios that meet the needs of broadband consumers. More importantly, Ubiquiti believes that these proposals will be acceptable to the FCC because they maintain the –27dBm/MHz protections put in place by the FCC and FAA for the TDWR systems, and because they do not place additional enforcement burdens on the FCC. This proposal employs the FCC’s existing and trusted infrastructure of certification labs/TCBs to ensure compliance instead of placing the burden on thousands of operators/installers to implement additional regulations to ensure compliance during equipment deployment.
Verder lezen...
The OEMs and the operators each came to the table with varying perspectives and approaches to solve the problem of how to reach a compromise with the FCC that would allow performance similar to the old 15.247 rules for point-to-point radios without causing issues for TDWR and other systems. As these diverse ideas were discussed and reviewed, the team at WISPA had the unenviable job of trying to incorporate the various positions into a single proposal.
Yesterday details of that proposal were released, and some may have noticed that Ubiquiti’s name was not on the list of manufacturers that had signed on. Although we participated in the calls and appreciate the efforts made by WISPA and other manufacturers, Ubiquiti decided to submit an alternate proposal to the FCC with what we feel would be best for WISP's and the industry. It is not our intent to contradict the WISPA proposal, but rather to provide another option for the FCC to consider.
Ubiquiti’s strategy is to pursue a simple, straight-forward, two-part compromise proposal with the FCC. The proposed changes (in bold) and a brief explanation are presented below.
- Modify 15.407(b)(4) to read (changes in bold):
"For transmitters operating in the 5.725-5.85 GHz band: All emissions within the frequency range from the band edge to 75 MHz above or below the band edge shall not exceed an e.i.r.p. of 17 dBm/MHz; for frequencies 75 MHz or greater above or below the band edge, emissions shall not exceed an e.i.r.p. of -27 dBm/MHz.”
This first change would modify the rules to take into account the technical challenges posed by the characteristic spectral shape of OFDM signals, which have regrowth components of up to 3x the 26dB bandwidth. However, this change still maintains the -27dBm/MHz emissions limits that the FCC and the FAA have already agreed to for adequate protection of the TDWR band. Finally, it also aligns the U-NII-3 OOBE with U-NII-1 OOBE rules, which allow 11dBm/MHz + 6dBi antenna = 17dBm/MHz.
2. Modify 15.407(b)(3) to read (changes in bold):
"For transmitters operating in the 5.47-5.725 GHz band: All emissions outside of the 5.47-5.850 GHz band shall not exceed an e.i.r.p. of -27 dBm/MHz.”
This change would make the verbiage consistent with the treatment of the 5250 MHz boundary between U-NII-1 and U-NII-2A in 15.407(b)(1) and (2), and would explicitly allow U-NII-2C transmitters to straddle the 5725 MHz boundary between U-NII-2C and U-NII-3.
Ubiquiti feels that these simple, minor changes will address the concerns of OEMs and operators and allow the manufacture and deployment of economically priced radios that meet the needs of broadband consumers. More importantly, Ubiquiti believes that these proposals will be acceptable to the FCC because they maintain the –27dBm/MHz protections put in place by the FCC and FAA for the TDWR systems, and because they do not place additional enforcement burdens on the FCC. This proposal employs the FCC’s existing and trusted infrastructure of certification labs/TCBs to ensure compliance instead of placing the burden on thousands of operators/installers to implement additional regulations to ensure compliance during equipment deployment.
Verder lezen...
