Enabling Sensor Network to Smartphone Interaction Using Software Radios

Recent advances in smartphone processing power have opened the possibilities for them to act as the processing component of software-defined radios (SDRs). For low-power sensor network systems using various communication protocols, this means that smartphones, when equipped with an SDR, can be their system management end-devices, (potentially) without the need for external communication modules. Nevertheless, the high processor and energy usage overhead of SDRs remains a major technical barrier that blocks the practical adoption of smartphone-based SDRs. In this work, we show that implementation flexibility at the software can relax this overhead. Specifically, we show, using an implementation of the low-power listening (LPL) Medium Access Control (MAC), that software improvements have the potential to significantly reduce the operational overhead of SDRs. Moreover, we show that implementing packet reception filters can help further reduce the performance overhead without sacrificing application-level message exchange qualities. Empirical results with a smartphone-based SDR suggest that by combining LPL with packet reception filters, the processing and energy overhead can be reduced by two to three orders of magnitude. We not only see this as a chance to practically realize smartphones as a wireless sensing system controller but also believe that the experiences with practical smartphone-based SDRs can provide guidelines for future wireless protocol and low-power radio designs that are suitable for mobile computing environments.