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