EPC: How's Your Handover?
Existing cellular networks handle voice and data on separate circuit-switch and packet-switch elements, while LTE will combine both voice and data on a single IP architecture. The EPC is the infrastructure used to connect mobile users to applications in an LTE network, supporting mobility and QoS management functions, which will be crucial for voice and video over the all-IP network. (See Who's Ready to Buy Evolved Packet Core?)
As established carriers build out their LTE networks, however, they will still need to support fall-back to voice services over 2G and 3G and handover to the older networks in areas where the newer technology isn't available. In fact, Verizon Wireless doesn't expect to switch to a voice-over-LTE system -- using the IP Multimedia Subsystem (IMS) -- until 2011 or 2012. AT&T Inc. (NYSE: T)'s plan for that switch won't take hold until 2012 or later. Both carriers are expected to keep investing in 3G until the end of the decade. (See LTE Watch: More Verizon Speed Tidbits.)
So clearly, a straightforward strategy for supporting voice calls and other services across both LTE and older networks should be a required part of any upgrade plan. Only 29 percent of respondents to our EPC survey, however, say that they have "a clear plan that includes support for real-time handover with preservation of QoS."
Nearly as many survey takers -- 27 percent -- say they are still "at square one" with LTE and cellular network integration plans. In the middle, 21 percent of respondents say they are "reasonably advanced" with network integration, if you don't count real-time handover and QoS, while 23 percent say they have a "general plan" for integration.
Deploying the LTE radio network and supporting backhaul is a major -- and expensive -- first step in enabling next-gen services. The survey makes it clear, however, that many respondents are still grappling with pulling their patchwork of networks to provide a consistent service in the future.
We already know that the earliest LTE offerings will be data-only. Verizon is expecting to offer modems and cards until sometime in the middle of 2011, when the operator plans to introduce a cellphone that runs calls over CDMA and data using the proto-4G technology.
Other carriers are generally not planning to try to match this schedule. In fact, 34 percent of the survey takers say they "probably won't begin EPC supplier evaluations until 2011 at the earliest." (See Report: Verizon Plans LTE Phone by Mid-2011.) You still have just over a week to make your voice heard in our EPC survey -- just click here to weigh in.
— Dan Jones, Site Editor, Light Reading Mobile