FCC moves to fix interoperability issues in lower 700MHz

US telecoms regulator The Federal Communications Commission (FCC) has endorsed a voluntary industry agreement to establish interoperable LTE service in the Lower 700MHz band. The move should give smaller US players access to a wider range of devices and increase competition.

The FCC said that the terms of the agreement serve the public interest by encouraging more efficient use of spectrum and enabling consumers to enjoy the benefits of greater competition.

US operators AT&T and Verizon Wireless operate their LTE networks using 700MHz spectrum blocks, as do a number of smaller carriers. It was these smaller operators that petitioned the FCC to create  interoperability changes arguing that certain smartphone vendors manufacture devices for AT&T’s and Verizon Wireless’  spectrum bands but not for their own.

The US was the first region to move on the 700MHz frequency (actually consisting of spectrum in the 698 to 806MHz bands) for cellular networking and in this region, the 700MHz band is actually made up of two separate bands: the lower band at 698-746MHz and the upper band at 746-806MHz. Only the A, B, and C blocks are paired in the lower band (leaving two unpaired blocks) but the upper is divided into five paired blocks. When the band plans were originally created, the A, B and lower C blocks of spectrum were intended to share a common band class, known as Band 12, and as a result, to share radio components.

But, citing interference concerns with broadcast TV in the A block, AT&T successfully lobbied for the creation of a separate band, Band 17, containing only the B and lower C block. This is effectively a proprietary band and got AT&T out of using A Block, Band 12 chips in its devices. But the absence of a heavyweight carrier using Band 12 (blocks A, B and lower C) gave chipset manufacturers little incentive to develop terminal radios for this specific band. At least this is the argument put forward by several of America’s smaller regional operators. Over 16 months ago Cavalier Wireless, C Spire, Continuum 700, King Street Wireless, MetroPCS, US Cellular, and Vulcan Wireless filed a petition with the FCC claiming as much, but also asserting that AT&T’s real motive was to squeeze smaller players out of the LTE market.

Taken in conjunction with Verizon’s approach— which with a good chunk of the upper band in its portfolio sold off some of its A block spectrum and concentrated on the upper C block where it almost has enough spectrum to roll out a nationwide network in the 700MHz band—it certainly looked like the smaller players will have a hard time getting in on the LTE sector as their networks will not be interoperable with the largest operators in the market.

Since AT&T effectively marginalised the A block, these smaller players claim to have struggled to get hold of devices. After all, manufacturers are mainly interested in large volume production, but also cannot sell affordable devices if there is not the scale to mass produce them. And many of these same rural carriers are calling for an extension to build-out deadlines as a result.

Read our feature on global 700MHz deployments

This latest move is a direct result of that lobbying and the FCC said that the standards were developed by several wireless providers and the Competitive Carriers Association, to give consumers more choice in using their devices with large and small carriers. It will promote widespread deployment of mobile broadband services, especially in rural areas, the regulator added.

The FCC has also approved an order that addresses interference concerns by modifying the technical rules of the D and E blocks in order to remove the likelihood of harm caused by attendant power levels, while continuing to allow high-value uses of these blocks.

The regulator concluded that interference from adjacent Channel 51 operations is unlikely to disturb B and C Block operations and found that these concerns are not an impediment to achieving interoperability.

The order also proposes to modify AT&T’s B and C block licenses to incorporate the commitments of AT&T and makes changes in construction requirements and deadlines for various E Block licensees in the Lower 700 MHz band.

Actions taken in this item improve wireless availability and competition, spur investment in and build out of the networks in the Lower 700 MHz band, and result in significant savings to the consumer, the FCC concluded.

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