Continuing on yesterday’s theme of how 4G networks differ from 3G, here are some insights into what makes core LTE infrastructure work. First, the packet-based nature of LTE networks allows for much greater QoS, security, and policy support than currently available in circuit-based 3G networks. With this increased capability comes a greater volume of control traffic – signaling, tracking and paging updates for devices, subscriber authentication, etc. To better handle the increase in control traffic, the LTE standard separates it out from normal consumer data traffic. In other words, in any LTE network there is one control plane and one consumer data plane.
Separating traffic types is logical for several reasons, including the fact that the two scale very differently. Demand for control functions increases depending on subscriber mobility, while demand for greater consumer data capacity is related to the amount of downloading and uploading users do. The most effective way to split the traffic is to put the two different types on two different platforms – an ATCA-based platform for control traffic, and an edge router for user traffic.
If your eyes haven’t glazed over yet, here’s where things get really interesting. All of the new control functions available through an LTE network require encryption and IP security when a user initiates a new mobile session. Ideally, operators want to accelerate these processes to cut down on latency and session set-up times. Acceleration is possible, but not common in current LTE hardware solutions, and, combined with using a dedicated platform for control traffic, it’s a critical component in creating a high-performance LTE network. A dedicated platform plus hardware acceleration equals greater throughput, increased capacity, and lower latency.
My deepest thanks to Motorolan Adebayo Onigbanjo for helping me to understand the core technology here, and specifically for spending so much time answering my layperson’s questions by email. Of course, this is just scratching the surface of LTE infrastructure, so if you want to dig deeper, feel free to check out more info over on the Motorola LTE site. You can also listen to Adebayo directly in the video explanation of evolved packet core technology he recorded out at 4G World.