Real-time SPI based radio control solving Hardware contention for asymmetric multicore LTE systems

Abstract

The paper discusses a software solution for contention between Long Term Evolution (LTE) layer 1 (L1) Time Division Duplex (TDD) software which is a soft real time system with strict timing compliance requirements and Linux Real Time operating system over shared Serial Peripheral Interface (SPI). The cores of the asymmetric multiprocessor systems are agnostic to each other's activities and share SPI in real time with no synchronization mechanism existing between them. The solution effectively mitigates the possibility of contention by converting non deterministic SPI transactions into externally triggered deterministic SPI transactions and provides mechanism to detect contention if it occurs under high L1 load scenarios. In the case of contention, an effective retry mechanism is put in place as a part of proposed solution. The paper concludes by providing various scenarios in which the proposed solution can be leveraged.