Multiuser zero forcing relaying with noisy channel state information [wireless ad hoc network applications]

We consider a wireless ad hoc network with single antenna nodes under a two-hop relay traffic pattern. Some of the nodes in the network form source/destination pairs, while the other nodes serve as amplify and forward relays. The relay gains are assigned such that the interference between different source/destination links is ed (multiuser zero forcing relaying). This essentially realizes a spatial multiplexing gain with distributed single antenna nodes. We introduce a specific zero forcing gain allocation and give comprehensive performance results, which include the impact of noisy channel state information and time variant channel coefficients. One of our most intriguing results shows that in a typical indoor scenario (delay spread<500 ns) multiuser zero forcing relaying at 5 GHz and pedestrian speed achieves a six fold increase in the sum rate of the network, even if we take the overhead for the measurement and the dissemination of the channel matrices into account.