Retransmission ≠ repeat: simple retransmission permutation can resolve overlapping channel collisions

Abstract

Collisions in overlapping channels can be a major problem in the deployment of high-speed OFDM networks. In this paper, we present Remap, a simple, novel paradigm for handling collisions in overlapping OFDM channels. Remap introduces a novel concept of retransmission permutation that permutes the bit-to-subcarrier assignment after each transmission, departing from the traditional, simply-repeat paradigm. Remap is simple to implement and able to exploit collision-free subcarriers to decode frames despite successive collisions in overlapping channels. We apply Remap to 802.11g to demonstrate that the diversity created by remapped frames can substantially improve decoding efficiency and improve wireless throughput. We implement our technique in software radio and demonstrate that it has potential to be deployed with simple software and firmware updates.