Measurement-Based Latency Evaluation and the Theoretical Analysis for Massive IoT Applications Using Bluetooth Low Energy

This paper presents measurement-based evaluation of Bluetooth (R) low energy (BLE) latency in a multipath environment containing a configuration of plural piconets. In power supply systems, many battery modules are connected in series. Cell monitoring units (CMUs) in each of the battery modules monitor the battery conditions and communicate to battery management units (BMUs). We adopted BLE in order to make this communication wireless and measured the latency of a configuration with 4 and 44 BLE modules mounted on the BMU and CMU side, respectively, in two battery boards. We found that the latency was 140-160 ms at CCDF=10(-4) for each master. Then, the data were analyzed from the perspective of collision probability. We found that the latency performance was explained to a certain extent by interference between piconets, and packet length in time slots.