Decentralized Interference Aware Link Adaptation Using Busy Bursts

This paper presents a new cross-layer approach to achieve active link adaptation and QoS support in ad hoc networks. Upon data reception in a transmission slot, receivers broadcast a feedback signal in a time-multiplexed mini-slot. The level of this feedback or busy signal is made dependent on the received signal from the intended transmitter and the required SINR (signal-to-interference-plus-noise ratio). Potential new interfering transmitters adjust their data transmit power based on the received busy signal power. It is demonstrated that due to the channel reciprocity in TDD (time division duplex) the received busy signal power is sufficient information to be able to maintain the SINR at the already existing links. Since multiple links are coupled via the busy signal, convergence and stability issues are analyzed.