A multichannel cooperative scheme for wireless networks and performance characterization

Paper presented at the 2007 IEEE International Conference on Acoustics, Speech and Signal Processing, ICASSP '07, Honolulu, HI.A cooperative random access protocol, namely alliances, was recently proposed for resolving collisions in wireless networks. In [1], we proposed an multichannel extension of alliances that in addition to cooperation diversity can exploit multipath diversity, and thus improve throughput at high traffic load and reduce packet delays. In this paper, we propose an improvement on [1] that makes more efficient use of available bandwidth and thus can achieve high throughput at all traffic loads. Furthermore, we present analytic performance characterization that provides insight on the relationship between achievable diversity and parameters like collision order, number of relays, channel length and number of carriers per subchannel

Cooperative Transmissions for Random Access Wireless Networks with Frequency Selective Fading

A random access protocol for wireless networks was recently proposed that by exploiting cooperation of network nodes can resolve collisions and thus achieve high throughput. In this paper we propose a multichannel extension of that approach that can lead to throughput improvement and significantly reduce packet delays at high traffic loads, while at the same time can handle frequency selective fading. The channel is divided into separable subchannels and each user can transmit packets over multiple subchannels. We propose schemes for resolving collisions on the various subchannels in a way that minimizes the average processing time for each collided packet. At the physical layer we propose an OFDM approach, where the subchannels are groups of carriers. I