Receiving Colliding LoRa Packets with Hard Information Iterative Decoding

Abstract

This paper presents symbol querying and symbol SIC, two techniques which allow LoRa receivers to recover colliding packets. A symbol querying receiver allows the demodulator and channel decoder to jointly search for the correct set of symbols during a collision. By operating in the frequency domain, both symbol querying and symbol SIC greatly limit the search space of possible packets, allowing for efficient implementations. Experimental results show that these techniques allow LoRa to elevate error detection to correction and outperform a BICM-ID receiver, receiving 3.8x more frames than a traditional LoRa receiver in a low SINR setting.