An ARQ-Based Cooperative Relaying Scheme for 5G IoT Slice
Musa U. Otaru, Mohammed Ajiya, Abdulkareem Adinoyi, Mohammed Aljlayl, Halim Yanıkömeroğlu · 2019
We introduce a new twist to the classical automatic repeat request (ARQ)-based cooperative relaying scheme. Here, we target a 5G slice for offering internet-of-things (IoT)-inspired services. In this 5G application segment (e.g., utility or smart metering), utility sensors or devices are expected to last for decades and, operate on tight power budgets, and the system can tolerate periodic stops to check the fidelity of previous transmissions. For this scenario, we employ a service provider-deployed relay that alleviates the IoT devices of their communication burdens. The source transmits for a certain time window or period without requiring acknowledgments (ACK) from the destination. At the end of this window, the destination sends an ACK. If negative, the relay is expected to assist. Thus, the relay transmits only intermittently, in either one transmission time slot or a few time slots, using a suitably chosen higherorder modulation constellation. If no error occurs, the source continues its transmission. The numerical results show that with just a few antennas at the relay, the new scheme provides both a reduction in the number of ARQ transmissions and a superior probability of bit error compared with a reference scheme. We adopt the two-parameter Weibull fading model to evaluate the performance of the proposed scheme.