Analysis and Design of Wireless Ad Hoc Networks With Channel Estimation Errors

Abstract

We investigate the impact and design of two important application dependent parameters - the effective per-node data rate and the outage constraint - for single-antenna point-to-point transmission in wireless ad hoc networks. In contrast to most existing work, our results explicitly account for the effects of channel estimation. We first derive a new outage probability expression, from which we completely characterize the feasible range of effective per-node data rate and outage constraint pairs which yield a positive transmission capacity, and derive an exact expression for the transmission capacity in such cases. We then proceed to optimize the transmission capacity under different assumptions, yielding considerable new insight. First, assuming that all nodes place a stringent outage constraint, the optimal pilot-training length is derived and this is shown to increase with the frame length according to a square root law. Consequently, for a sufficiently long coherence interval, we show that there is a negligible loss in transmission capacity when using this optimal pilot-training length. Second, we show that if nodes place a constraint on their required effective data rate, then the outage constraint yielding the maximum transmission capacity is quite large. Moreover, this result demonstrates that, from an overall network perspective, it is preferable to operate with a higher total data rate (aggregated across all nodes) at the expense of a lower reliability.