An Optimal methodology for efficient resource distribution among contending Sims in a single RF subsystem multi-sim UE

With the evolution of wireless broadband technology and increasing demand of multi-sim User Equipment (UE), new challenges of resource sharing arise where conventional methods of creating small gaps in resource usage pattern of one SIM do not suffice. The advent of Voice over LTE (VoLTE) services accompanied by the immense mobile broadband demand of the users, require continuous resource availability on both the SIMs even in a single RF subsystem. Dual SIM Dual Active (DSDA) architecture that can meet the above requirements is not popular due to higher associated cost. In this paper, we consider the fundamental problem of resource sharing across SIMs in multi-sim architecture especially Single Receive Dual SIM Dual Standby (SR-DSDS) and Dual Receive Dual SIM Dual Standby (DR-DSDS). We formulate resource sharing as an optimization problem to maximize the ratio of resource allocation fairly for each contending SIM considering several important factors like current buffer occupancy, average time criticality of the buffer content and channel quality of respective SIM. We solve the formulated optimization problem using Karush Kuhn Tucker (KKT) conditions to derive the closed-form expressions for optimal resource allocation. We also compute the number of transitions possible with the derived optimal fair allocation in a practical multi-sim architecture. Additionally, we present the analytical results to depict the efficacy of the algorithm.