Opposition to the Proposal

The ex parte from Apple et al concludes that ‘RKF’s findings are clear: unlicensed services can successfully coexist with the primary services present in the 6 GHz band.’. This conclusion is misleading as the RKF study has since been discredited. The study is founded on a host of incorrect assumptions. Opposition to Apple et al’s proposal has been submitted to the FCC by a number of parties including AT&T, the FWCC (Fixed Wireless Communications Coalition) and the NSMA (National Spectrum Management Association). Here we consider some of the key points raised by reviews of the RKF study.

The FWCC opposition ex parte, March 2018, is rich in technical detail and includes analysis of existing, real world microwave receivers in eight key cities across the United States. They considered the impact to these receivers in the presence of uncontrolled, unlicensed devices operating under the conditions proposed by Apple et al. The FWCC study found that uncontrolled use of RLANs at the power levels and numbers proposed would result in ‘widespread harmful interference’ to microwave receivers. In fact, the study demonstrates that every receiver within the scope of the eight-city study would experience some level of interference. Further, 70% of the receivers would suffer a high level of interference that would degrade fade margin by 10dB or greater. One in thirty receivers would see extreme interference (40dB or greater) that would effectively disable them. The FWCC’s ex parte also points to one of the most concerning issues regarding spectrum sharing with unlicensed devices; the fact that there is obviously no record of ownership or location of the devices, making it virtually impossible to identify sources of interference. The FWCC study concludes that Apple et al/RKF cannot prove non-interference to incumbent services and so the FCC must reject the proposal.

AT&T’s March 2018 analysis of RKF’s study raises similar concerns, including the difficulties surrounding the identification of interferers, due to lack of records regarding location/owner and also the fact that interference may not be consistent. They dispute several of RKF’s assumptions, including the distribution of power/height/number of RLAN’s; RKF’s study averages RLAN power by geography, averages the number of RLAN’s geographically and averages the height at which RLANs will be located. This obviously casts a kinder light on use of RLANs and fails to address the extremes; density of RLANs in certain cities, use of RLANs at great height and operation at maximum power of around 4W. Its ex parte concludes that ‘RKF gives the overly optimistic and misguided impression that unlicensed services can successfully coexist with the primary services present in the 6GHz (band)’.

What can I do to protect the 6GHz band?

By signing, you will be endorsing the ex parte opposition letter shown here. Your organization’s name will then be included in a submission to the FCC, made by Aviat Networks.