Invention Grant
- Patent Title: Circuit-switched fallback (CSFB) call setup utilizing multiple RF receive chains
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Application No.: US15333550Application Date: 2016-10-25
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Publication No.: US09894564B2Publication Date: 2018-02-13
- Inventor: Li Su , Wanping Zhang , Qiang Miao
- Applicant: Apple Inc.
- Applicant Address: US CA Cupertino
- Assignee: Apple Inc.
- Current Assignee: Apple Inc.
- Current Assignee Address: US CA Cupertino
- Agency: Meyertons, Hood, Kivlin, Kowert & Goetzel, P.C.
- Main IPC: H04W4/00
- IPC: H04W4/00 ; H04W36/00 ; H04L29/06

Abstract:
In a wireless communication system, a user equipment device (UE) may undertake a circuit-switched fallback (CSFB) process by using or more secondary radio frequency (RF) receive chains to search for candidate circuit-switched (CS) cells, in parallel with using a primary RF receive chain to wait for an extended service request (ESR) response. The UE may send, using a first RF receive chain, an ESR message on a packet-switched (PS) network in response to receiving a CS voice call page on the PS network. The UE may also start an ESR timer upon sending the ESR message, and monitor, using the first RF receive chain, for receipt of an ESR response on the PS network. While monitoring for receipt of the ESR response, the UE may use a second RF receive chain to acquire an initial CS network, and detect whether the ESR timer expires before the ESR response is received.
Public/Granted literature
- US20170041834A1 CIRCUIT-SWITCHED FALLBACK (CSFB) CALL SETUP UTILIZING MULTIPLE RF RECEIVE CHAINS Public/Granted day:2017-02-09
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