Spatial Multiplexing with MRC and ZF Receivers in Ad Hoc Networks

This paper investigates the performance of point-to-point spatial multiplexing with stream control and slotted ALOHA in ad hoc networks. In particular, we derive new closed-form outage probability, network throughput and transmission capacity expressions for spatial multiplexing with maximum-ratio-combining (MRC) and zero forcing (ZF) receivers. From these expressions, we show that the relative throughput of MRC and ZF receivers is dependent on node intensity and SINR threshold levels. In addition, we present a new transmission capacity scaling law for ZF receivers, which shows that increasing the number of transmitted data streams can either increase or decrease the transmission capacity depending on the path loss exponent and number of receive antennas. We also present conditions such that the transmission capacity using spatial multiplexing with ZF receivers is greater than orthogonal space time block codes.