Optimised handover procedures and protocol between EUTRAN access and non-3GPP accesses (S102); Stage 3
The present document specifies the stage 3 of the Evolved Packet System S102 interface between the MME and the 1x CS IWS to relay the 1xCS signalling messages documented in 3GPP TS 23.216 [2] and 3GPP TS 23.272 [4]. 1x CS signalling messages are those messages that are defined for A21 interface as described in 3GPP2 A.S0008-D [3] and 3GPP2 A.S0009-D [6]. The S102 interface messages shall be based on A21 messages.
The S102 interface is used to support UEs that do not transmit and receive on both the LTE and 1x radio interfaces simultaneously. S102 protocol aspects for SRVCC from E-UTRAN access to 3GPP2 1xCS is covered in this specification. Handling of non-voice component and protocol aspects for SRVCC from 3GPP2 1xCS to E-UTRAN direction is not specified in this release.
The S102 interface is also used to support CS fallback to 1xRTT procedures from E-UTRAN access to CDMA 1x RTT CS domain and to support SMS over S102 with the CDMA 1xRTT CS domain through support of registration over EPS procedures as specified in 3GPP TS 23.272[4].