Improving random access efficiency with uniformly deployed relays and interference cancellation for energy-constrained M2M devices

In this paper, we attempt to improve the efficiency of random access employed for a massive number of energy-constrained M2M devices to transmit their data to a base station (BS) by exploiting relaying and interference cancellation (IC). Each device transmits a single packet with a minimum required power, which is then forwarded by surrounding relay(s) to derive a benefit of IC at BS. While IC can increase the number of packets successfully decoded at BS, relaying increases the overall traffic load since each relay joins the random access sharing the radio resource with the devices in order to forward the received packets. Taking this trade-off into account, we investigate a possible gain brought by relaying and IC in terms of average number of successfully received packets at BS. Our numerical results show that the efficiency of random access from a massive number of devices can be significantly improved only by uniformly deploying a small number of relays inside a cell. The proposed approach does not require each M2M device to redundantly transmit their data to apply IC, which is favorable from a viewpoint of energy-efficiency of each battery-operated M2M device.