Adaptive Modulation Rule Change Called Key to Broadband Deployment
The Fixed Wireless Communications Coalition said most commenters agree about the benefits of adaptive modulation, in reply comments as the FCC asked whether companies should be allowed to reduce data rates for point-to-point transmissions to keep a link in service. The FWCC, joined by Alcatel-Lucent, Motorola and Ericsson, had asked the FCC to clarify that adaptive modulation is permissible under rules for fixed wireless transmitters operating in the 4, 6, 10, and 11 GHz bands (CD May 20 p4). The group argued that the FCC could provide clarification without a full scale rulemaking in the interest of a quick decision.
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Interest is high, since the bands provide wireless public safety backhaul, cell site backhaul and are used for control of the electric grid as well as natural gas and oil pipelines.
“All of the commenters agree that adaptive modulation will improve performance and enhance system reliability,” the FWCC said. Verizon raised concerns that a grant of the request would encourage installation of substandard, spectrum-inefficient systems that meet the required minimum data rate on average, but operate for a substantial percentage of the time at data rates well below those specified by the rules, the group said. “Verizon raises a potentially important issue, but one having no direct connection to adaptive modulation,” FWCC said. “It addresses the property of ‘availability,’ or percentage of time a system operates at its full rated data speed. The present request has no effect on policies or rules relating to availability.”
AT&T, Clearwire, Dragonwave, Harris Stratex Networks and United States Cellular Corp. all support the petition seeking clarification, Motorola said in its reply comments. “With increasing demands for new broadband services for consumers, the need for backhaul spectrum to support those wireless networks also increases,” Motorola said. “As new commercial wireless spectrum comes online -- for example, the Broadband Radio Service or the Advanced Wireless Service -- there is a need for either wireline or wireless backhaul to connect each base station to the overall network.” Motorola said granting the request “will ensure that the Commission’s fixed microwave rules are well-positioned to support the increasing demand being placed on wireless backhaul to support the Nation’s broadband goals.”
Verizon and Verizon Wireless emphasized in reply comments they are “not opposed to the use of adaptive modulation per se.” But the FCC should make changes that would permit adaptive modulation through a rulemaking, Verizon said. “A declaratory ruling is not a substitute for a rulemaking proceeding and should not be used to change the fundamental meaning of a rule,” Verizon said. “As noted in Verizon’s initial comments, absent clear enforceable limits, there is a substantial potential for abuse that will limit the spectrum available for future users of the bands.”