Threshold Adjustment-Timed Window Combined Algorithm in Adaptive Modulation and Coding

Abstract

Adaptive modulation and coding (AMC) is a powerful technique adopted by TETRA Release 2 to improve throughput, especially in wireless packet oriented channels. It is characterized by the adaptation of different modulation and coding schemes (MCS) to the channel state. In this paper, by taking advantage of the Threshold Adjustment (TA) algorithm, an improved Timed Window (TW) algorithm, named the TA-TW combined algorithm is proposed. Analytical expressions for performance metrics of the improved algorithm, such as throughput and channel occupancy, are derived. The numerical results show that TA-TW combined algorithm provides a better performance than the TW algorithm by adjusting the thresholds to the channel condition adaptively.