Latency and Memory Constraints Aware Protocol to Optimize Data Throughput at a 5G-NR Base-Station Supporting Multi-SIM Phones

This paper analyzes the memory and latency requirements at a 5 G -NR base station that supports dual-SIM dual-radio cell phones that periodically tune away to monitor voice-call pages on a 3G network. Data transfer to the phone is modeled using a stop-and-wait protocol. We derive expressions for the mean of the number of attempts and the mean of the square of attempts taken to transmit the data. Data arrival at the base-station is modeled as a Poisson process, and the Average Number in Queue and the Average Wait Time are derived using the Pollaczek-Khintchine formula for an M/G/1 queue. It is shown that both are higher for a given arrival rate when there is a complete tune-away versus the tune-away of a single antenna. Consequently, we propose a protocol that requires a dual-SIM phone to request a lower rank to tune away only the diversity antenna. Further, to operate within the memory and latency corresponding to the original single-SIM budgets, we propose a protocol between the base station and the data source to reduce the data-rate. An algorithm is proposed to determine the data-rate based on the tune-away duration and the original budgets.