Improving LoRa Scalability by a Recursive Reuse of Demodulators

Long Range (LoRa) is a protocol that enables low-power wireless communications over long distances for a wide range of IoT applications. Its main drawback is its limited throughput, which is further reduced by the small number of demodulators in the hardware of the gateway. In this paper, we propose to use each demodulator as efficiently as possible. To do so, we reuse them for short frames during the preamble of long frames. By smartly planning the demodulation of multiple frames, the proposed method enables a recursive reuse of each demodulator. Compared to the benchmark packet arbiter policy, our method is shown to offer throughput and fairness enhancements even with a large number of users, thereby improving the scalability of LoRa systems. Our simulation results show that when the number of nodes is large, 6.5% more frames are decoded and the rate fairness among nodes is improved by 11%.