Spatial Graph Coupling for Wireless Communications

A novel approach to information transmission over multi-terminal channels is proposed. In this approach, the information is transmitted in the form of multiple independent data streams that couple in the wireless channel into structures that can be decoded using a low-complexity iterative receiver allowing for a simple implementation. Our recent results prove that the proposed technique achieves the capacity of the Gaussian multiple-access channel even for the case of equal rate and power transmissions providing a nearly universal way for joint decoding of signals. The objective of the project is to utilize the novel modulation format to establish practical algorithms for communication over multi-terminal channels in which a group of terminals communicates to another group of terminals utilizing coordination and cooperation for transmission and reception of signals. Terminal cooperation provides a possibility to substantially increase network throughput without relying exclusively on the costly bandwidth and power resources.* Technical details of the research plan include interference managing precoding via resource allocation for the data streams and partial decoding in which all signals are demodulated but only some are decoded. Terminal cooperation will be addressed via non-orthogonal relaying in which the relay and the source can transmit information simultaneously while the destination employs joint decoding of signals. Transmission over inter-symbol interference channel and multiple antenna communication will be addressed including symbol estimation based on correlated received data into the demodulation process. Throughput maximization will utilize the recently developed theory of spatial graph coupling that provides an instrument to construct graph structures on which low-complexity iterative processing achieves optimal performance.* The designed algorithms can provide a practical realization of cooperative multi-point (CoMP)*communications in cellular systems improving quality of service and saving billions of dollars in costs of transmission frequency bands for the telecommunications industry in Canada and worldwide.*