The Effect of Carrier Frequency Offset on Collision Resolution in Wireless Networks

A random access protocol for wireless networks named ALLIANCES was proposed, that via cooperation of network nodes resolves collisions and achieves high throughput. Cooperative transmissions introduce multiple frequency offsets that arise from differences between receiver oscillators and those each node. These offsets were not taken into account in the original ALLIANCES. This paper introduces a method to identify and eliminate frequency offsets so that channel estimation and bit recovery can be performed. The proposed approach is tested on real collision data obtained at a wireless communications testbed.