Abstract

Extensive research has demonstrated the potential improvement in physical layer performance when multiple radios transmit concurrently in the same radio channel. We consider here how such cooperation affects the required node density for full connectivity and percolation for various path loss exponents (PLEs) in large wireless ad hoc networks. For one-dimensional (1-D) extended networks, in contrast to noncooperative networks, full connectivity occurs for any node density when the PLE <= one. Conversely, there exist unconnected nodes with probability one when PLE > 1, and the network does not percolate for any node density if PLE > 2. The existence of percolation remains an open problem for 1 < PLE <= 2 in the one-dimensional (1-D) case. In two-dimensional (2-D) extended networks with noncoherent cooperation, full connectivity is achieved for any node density with PLE <= 2. Conversely, there exist disconnected nodes with probability one when PLE > 2; however the cooperative network percolates for node densities above a threshold which is strictly less than that of the noncooperative network.

The above results hold when in the presence of receiver cooperation. We also present results for the case that senders cooperate whereas receivers do not.

Joint work with D. Goeckel, B. Liu, L. Wang, C. Westphal