Protocol for Reduction in Network Resource Wastage for 4G Dual SIM Dual Standby User Equipment

Abstract

A user equipment (UE) with Dual Subscriber identity- module (SIM) Dual Standby (DSDS) feature can connect to two network operators, such as- SIM is connected to one operator and one Protocol Software Stack (PSS) while both SIMs share the same Integrated Radio Frequency Circuit (RFIC).UE schedules SIM-1 to communicate with Operator-1 and at the same time SIM-2 remains standby and vice versa. The ongoing data session with Operator-1, through SIM-1 is interrupted while the UEs RFIC tunes away to attend a higher priority signaling through SIM-2 to Operator-2. This tune away procedure of RFIC results in allocated Physical Channel Resource (PCR) wastage at Operator-1 for SIM-1 during the tune away period. After the end of tune away at SIM-1, it further more suffers from low PCR allocation from Operator-1, because of no response from SIM-1 during tune away period. To overcome the above challenges, to the best of our knowledge, for first time this paper proposed Signaling indication from UE to network for RFIC tune away event to reduce network PCR wastage. This signaling is done by: (a) Radio Resource Control (RRC) layer (b) Medium Access Control (MAC) layer (c) Layer 1 (L1). Each of the above-mentioned signaling has particular level of latency and reliability. We propose to apply above-mentioned signaling in scenario specific manner to address all possible tune away events. Through extensive simulation derived from mathematical modelling and measurements obtained from test bed with commercial DSDS UEs, the results reveal an improvement in overall PCR utilization for an operator and increase in UE admission by up to 30% in comparison with current DSDS solutions.