An Introduction to LTE: LTE, LTE-Advanced, SAE, VoLTE and 4G Mobile Communications, 2nd Edition

Chapter 16Inter-operation with Non-3GPP Technologies

In the last chapter, we saw how LTE can inter-operate with the older 3GPP technologies of UMTS and GSM. This is not the limit of LTE's capabilities, as it can also inter-operate with communication networks that are defined by other standards bodies. These capabilities help operators offload traffic onto other communication technologies such as wireless local area networks and help operators of other technologies such as cdma2000 upgrade to LTE.

We begin by discussing the architectural options and signalling procedures through which LTE can inter-operate with a generic non-3GPP communication network. The specifications allow a mobile to transfer between LTE and another technology while maintaining its IP addresses and its connections with any external servers, but do not include any support for optimized handovers. We then move to the special case of inter-operation between LTE and cdma2000. Here, the specifications do support optimized handovers, so allow a mobile to transfer between the two technologies with no packet loss and with a minimal break in communications.

The most important specification for this chapter is TS 23.402 [1], which defines the inter-operation architecture and presents a high-level view of the signalling procedures. Other 3GPP specifications define the layer 3 signalling messages on the individual interfaces, while two 3GPP2 specifications [2, 3] define inter-operation between LTE and cdma2000 from ...