Scalable Full Duplex Dense Wireless Networks (SENSE)

In response to the growing demands for delivery of content-rich and delay-sensitive services, network architectures for 5th generation and beyond wireless communication systems are becoming more and more dense. This illustrated through the ever increasing deployment of small cell networks as well as machine-to-machine (M2M) communications. This trend, whilst improving network capacity, will still necessitate reuse of available resources such as frequency spectrum within smaller areas by larger number of nodes/cells, which in turn would adversely affect the quality of service.

On the other hand, by allowing simultaneous transmission and reception in the same frequency band, In-band Full-Duplex Communication (IFDC) technology potentially enhances the spectral efficiency of a single point-to-point (P2P) channel by 100% over the conventional half-duplex communication. IFDC also enables the nodes, e.g. in P2P scenarios, to receive channel feedback or sense other channels whilst transmitting data, which shortens the latency compared to conventional half duplex communication with time-division-duplexing. Moreover, using full duplex relay nodes in multi-hop scenarios can potentially reduce the end-to-end latency by enabling simultaneous receiving and relaying. Practical implementation of this technology requires rigorous interference cancellation methods at each node to suppress the strong self-interference imposed on the receiver by the transmitter of the same node. The major bulk of research on IFDC has focused on self interference cancellation (SIC), and the respective state-of-the-art technology can achieve a high level of SIC at full duplex terminals; hence the IFDC technology has become closer to commercial deployment by industry.

Deploying IFDC in realistic dense settings entails new range of technical challenges, and opportunities alike. IFDC can yield substantially greater network throughputs and delay reductions over half duplex networking by deploying the technology in denser networks. However, attaining such gains demands for efficient scalable resource allocation and multi-node interference control methods. This great potential of 'full-duplex dense networks' in 'scalable service provisioning' has not been addressed to date by the research community in sufficient depth.
At physical-layer, new resource allocation challenges arise in IFDC networks; for instance, in the design of concurrent channel sensing and data transmission, and in adapting transmit power of the nodes to their variable self-interference. Also, using IFDC in dense scenarios will affect design of the protocols in the higher layers; for instance IFDC would entail greater chance of packet collisions and multi-node interference, which demands for new medium access control (MAC) protocols suited to the emerging dense full duplex networks. Furthermore, IFDC will enable full duplex relaying in multi-hop communication, hence requires new Forwarding-layer/Network-layer protocols to deal with the new full-duplex forwarding paradigms.

For conventional half duplex scenarios it is known that network throughput and quality of services can be improved through cross-layer methods, particularly with co-design of physical and MAC layers or MAC and Network/Forwarding layers. In fact for optimal scalability of heterogeneous services in full duplex dense networks, cross-layer approaches are inevitable. This project aims to propose systematic design of resource allocation and interference suppression techniques and algorithms at physical, MAC and Forwarding layers in order to enable substantial throughput gain and delay reduction by deploying full-duplex communication in dense wireless networks. These new methods will pave the way for deploying scalable service provisioning in the emerging dense wireless networks.

Through the adoption of SENSE based technology for future wireless access systems, the general public will benefit from this EPSRC funded activity, given our vision of improved spectrum and power efficiencies as well as reduced network latencies. The project outcomes will have a profound impact on addressing wireless capacity predictions and end-to-end service delay for networks of 2025 and beyond, thus helping to meet public expectations of future wireless connectivity. The role of industry, and in particular our industrial partners, will be paramount here given the significance of international standards in the wide spread adoption of new wireless methodologies in the sector. The dissemination of our research outputs to the standardisation bodies (3GPPP and the ITU) as well as industry fora (MWC, Cambridge Wireless, etc) is seen as an important contribution.

Clearly, our industrial partners being closely aligned with our research, are well positioned to exploit the research outcomes within their products and services. This potentially encompasses transceiver chip set development, wireless network architecture and management, consumer products with enabled wireless connectivity as well as test and measurement.