This Notice of Proposed Rulemaking  involves interoperability issues in the Lower 700 MHz spectrum band. Currently, there are two distinct sets of technical specifications for devices operating in the Lower 700 MHz band, resulting in a lack of interoperability in the Lower 700 MHz band. In 2009, an alliance comprised of four Lower 700 MHz A Block licensees filed a petition for rulemaking  requesting the Commission to require that all mobile devices for the 700 MHz band be capable of operating over all frequencies in the band.
The 700 MHz Band is comprised of 108 MHz of spectrum:
The Lower 700 MHz spectrum band consists of 48 MHz of spectrum, divided into five spectrum blocks:
The 3rd Generation Partnership Project (3GPP)  is a consensus-driven international partnership of industry-based telecommunications standards bodies. 3GPP developed standards for Long-Term Evolution (LTE) wireless broadband technology. There are two different 3GPP operating bands in the Lower 700 MHz band: 1) Band Class 12, which covers operations in the Lower A, B, and C Blocks; and 2) Band Class 17, which covers operations in the Lower B and C Blocks only. Entities involved in the creation of Band Class 17 during the 3GPP proceedings assert that it was necessary to create a separate band class for Lower 700 MHz B and C Blocks in order to avoid interference issues from digital television (DTV) Channel 51 and high power operations in the Lower E Block.
The group that filed the petition for rulemaking make essentially two arguments: 1) Equipment vendors currently first serve the needs of Band Class 17, which covers the Lower B and C Blocks only, and is dominated by AT&T; and 2) Equipment manufacturers have little incentive to innovate and provide compatible devices for smaller markets, particularly when providing interoperable devices would run contrary to their largest customers’ desires.
Supporters of an interoperability requirement assert that Band Class 17 devices preclude supporting operation on Lower A Block spectrum and that this is contrary to the public interest. Supporters argue that small providers that acquired 700 MHz Lower A Block licenses are left without viable and widely usable equipment options. They contend that interoperability is necessary for Lower A Block licensees to obtain devices with competitive economies of scale. The group also contends that full support of Band Class 12 will maximize roaming opportunities.
On the other hand, others argue that the distinct band classes are necessary, and that without Band Class 17 filtering, Lower 700 MHz B and C licensees will face greater levels of harmful interference. They contend that the existing 3GPP band classes were crafted through an open process and are responsive to the realities of the engineering and manufacturing constraints of the Commission-defined spectrum blocks.
The Notice of Proposed Rulemaking addresses numerous issues and requests comment on, among other things:
The Notice of Proposed Rulemaking seeks to resolve whether a single, unified band class for devices in the Lower 700 MHz band would result in harmful interference to the operations of Lower 700 MHz B and C Block licensees, and whether, if harmful interference exists, it reasonably can be mitigated. The Notice of Proposed Rulemaking explores various options to help achieve the ultimate goal of interoperability.