DuoRelay: Parallel Interference Nulling using Full-duplex Relaying

In recent years, the volume of uplink traffic in our networks has grown and become increasingly diverse. Typically, concurrent uplink transmissions can be made possible by allowing the APs to collaborate over the wired backbone for control signalling as well as data decoding. In our paper, we remove the dependency over the wired backbone for data decoding without requiring any pre-coding constraints at the clients' end. Our paper contrasts with other existing works which can decode concurrent uplink data-streams without the backbone as they either need multiple antennas at the transmitters/receivers, pre-coding at the transmitters or antennas to be physically moved at the receivers. In our paper, we address the problem space of single antenna transmitters and receivers and enable concurrent uplink transmissions by leveraging the recent developments in full-duplex wireless communication. We make each of our APs act as full-duplex relay nodes. Each AP cancels its own client's signal at the other AP, thus enabling themselves to clearly hear their own clients without requiring any pre-coding at the clients' end. We implemented and evaluated our scheme using USRP N210 software defined radios and achieved upto 1.48x throughput gains over TDMA. The throughput improvement over TDMA is upto 1.7x in our system level simulations with our greedy node selection algorithm.