Circuit-switched fallback (CSFB) call setup utilizing multiple RF receive chains

摘要

A user equipment (UE) communicating in a wireless communication system may include a primary radio frequency (RF) receive chain (PRFRC) and one or more secondary RF receive chains (SRFRCs). When the UE is to undertake a circuit switched fallback (CSFB) process, the UE may use the one or more SRFRCs to search for candidate 2G/3G cells while in parallel using the PRFRC to wait for an ESR response. The UE may initiate a CSFB process and send an extended service request (ESR) message on a packet-switched network. The UE may monitor for receipt of an ESR response on the packet-switched network using a first RF receive chain, and while monitoring, also acquire an initial circuit-switched network using a second RF receive chain. The UE may start an ESR timer when sending the ESR message, and detect whether the ESR timer expires before the ESR response is received.

主权项

1. A method for circuit-switched fallback (CSFB) in a wireless communication system comprising:
initiating a CSFB process; sending an extended service request (ESR) message on a packet-switched network; monitoring for receipt of an ESR response on the packet-switched network using a first radio frequency (RF) receive chain; in parallel with monitoring for receipt of the ESR response, acquiring an initial circuit-switched network using a second RF receive chain; starting an ESR timer when sending the ESR message; and detecting whether the ESR timer expires before the ESR response is received.