Scheduling and Performance of Multihop Radio Networks with Multiuser Detection

Abstract— Incorporating multiuser detection (MUD) at receivers in a Multihop Packet Radio or ad-hoc Network has the potential to drastically improve performance. In this work, possible improvements are investigated and it is suggested that the Channel Coding Theorem be used for accurate modeling of the radio channel. With this model, MUD is shown to be more beneficial to ad-hoc networks employing spread-spectrum signals and in this case, the single-hop throughput increases linearly with the number of packets received. The delay performance of a narrow-band system employing Spatial-Time Division Multiple Access (S-TDMA) for scheduling is considered. MUD is incorporated into previously-proposed scheduling methods and a new method is proposed for generating the S-TDMA schedule by exploiting the detector. By simulation, MUD is shown to provide shorter length schedules, with the proposed method outperforming a systematic search. These results show that MUD typically provides a 20% reduction in the S-TDMA frame length, and thus decreases delay at low loads.