The objective of the project was three fold:
1. To quantify the benefits to the capacity and coverage of cellular/multihop networks with terminal array processing
2. To Investigate what modifications are required for routing algorithms and data scheduling to support terminal array processing and their impact on network performance
3. To develop practical receiver algorithms for terminal antenna arrays
This project studied two important techniques for improving the performance of wireless networks, namely antenna arrays and the use of relays, which forward information between wireless terminals. The objective was to study the interaction of these two concepts and to design promising new approaches for relay communications.
The point of this proposal was to investigate the capacity of future wireless networks incorporating multihop wireless links. These links involve the use of one or more intermediate relays, located between the source and destination, which can assist the communication. There were three major work packages undertaken for the project.
Initially, the effects on the capacity of a cellular system of using terminal antenna arrays and multihop networking was investigated. A system which allocated the same data rates to all users was found to benefit significantly from multihop techniques. The use of antenna array reception techniques were found to improve network performance but to reduce the likelihood of multihop links being required.
Secondly, the work will investigated the impact of realistic scheduling and relaying techniques on the performance of the cellular/multihop systems. It was found that by using two relays, inefficiencies in the relay forwarding process can be reduced significantly, improving the data throughput of the network.
Finally, a detailed investigation of the best multihop forwarding technique was performed to understand the trade-off between performance and complexity. As part of this work, a novel relaying method called hybrid relaying was proposed for multiple antenna systems. This involves combining the antenna signals at the relay in such a way as to minimise the effects of receiver noise and optimise multihop link performance.