Link adaptation in wireless data networks for throughput maximization under retransmissions

In this study, we propose a new link adaptation algorithm for wireless data communications. Compared to the existing algorithms, the most distinguishing feature of this algorithm is the implementation of a no-transmission mode, a so called mode 0, for active users. In particular, transmissions to or from a user are not permitted while the estimated signal quality of the user, expressed as signal-to-interference ratio (SIR), is lower than a cutoff threshold. Unlike the traditional admission control, which is performed only once upon admitting a user, mode 0 is an integral part of an ongoing link adaptation process for admitted users. This mode automatically controls the system load, reduces unnecessary retransmissions, and therefore, improves the overall throughput. Our simulation results show that for the system under study, a throughput improvement of up to 75% can be achieved