A New Design of Q-CHAIN on WIMAC: A Throughput-Optimal Random Access MAC Protocol with Piggyback Transmissions

Abstract

While IEEE 802.11 DCF has been the dominant protocol used in the existing WLANs, it suffers the low efficiency from the increasing devices connected to the network. The more nodes under one AP, the more collision it will happen in the network. To reduce the overhead contention issue, we propose a new design of Q-CHAIN. The original Q-CHAIN achieves a MAC protocol using piggyback transmissions, which can update the piggyback relation on the client side independently. However, it is not robust under unreliable data transmission and still needs an intelligent AP to decode special packets and transmit special ACKs. The new design of Q-CHAIN can handle unreliable data transmission. It can be cooperated with the legacy DCF and inherit all advantages of the original Q-CHAIN. Moreover, it does not need an intelligent AP and can be integrated into the existing network in a friendly way. We implement the new design of Q-CHAIN on WiMAC, and the experiment results show the performance of Q-CHAIN with the legacy DCF and the legacy CHAIN.