Relay-Assisted User Scheduling in Wireless Networks with Hybrid-ARQ

TL;DR

This paper investigates relay-assisted user scheduling in downlink wireless networks using hybrid-ARQ, optimizing queue management and retransmissions to improve network efficiency with a novel priority-index policy.

Contribution

It introduces an optimal scheduling policy based on priority indices for relay-assisted wireless downlink transmission with hybrid-ARQ.

Findings

Priority-index policy is optimal under certain cost functions.

The policy effectively minimizes queue lengths and retransmissions.

Applicable to systems with Poisson packet arrivals.

Abstract

This paper studies the problem of relay-assisted user scheduling for downlink wireless transmission. The base station or access point employs hybrid automatic-repeat-request (HARQ) with the assistance of a set of fixed relays to serve a set of mobile users. By minimizing a cost function of the queue lengths at the base station and the number of retransmissions of the head-of-line packet for each user, the base station can schedule an appropriate user in each time slot and an appropriate transmitter to serve it. It is shown that a priority-index policy is optimal for a linear cost function with packets arriving according to a Poisson process and for an increasing convex cost function where packets must be drained from the queues at the base station.