CALL SETUP LATENCY OPTIMIZATION FOR LTE TO 1XRTT CIRCUIT SWITCHED FALL BACK

摘要

A method and apparatus for reducing call setup latency in an LTE network is disclosed. Services in a 1×RTT network are provided for both single receiver (SRx) and Dual Receiver (DRx) User Equipment using CSFB (Circuit Switched Fall Back). When an idle UE requests a CSFB to 1×RTT service and related PS (packet service) Suspension in the LTE network, an eNB can reduce or eliminate the exchange of RCC (Radio Resource Control) messages with the UE before UE is redirected to 1×RTT for CSFB service. Eliminating unnecessary messages reduces call setup latency. The number of exchanged messages can be reduced when the eNB broadcasts an indicator that the eNB supports CSFB and an MME (Mobility Management Entity) sends a message to the eNB indicating that a UE is requesting CSFB.

主权项

1. A method for reducing call setup latency in an LTE network comprising the steps of:
broadcasting an indicator that an eNB supports Circuit Switched Fall Back (CSFB) for dual receiver user equipment (DRx UE); receiving a message requesting connection to a voice-centric call processing network from a user equipment (UE), the message comprising a payload including at least a CSFB indicator; forwarding the payload to a mobility management entity (MME); receiving, from the MME, a request message that comprises the CSFB indicator; sending a connection release to the UE without exchanging any further messages with the UE; and returning a UE Context Release Request to the MME with an indicator that the UE is accessing the voice-centric call processing network, without sending an expected response message in response to the request message from the MME.