Quality of Service Oriented Analysis of Cross-Layer Design in Wireless Ad Hoc Networks

In wireless ad hoc networks, cross-layer design aims at reducing multiple access interference and thus obtaining a higher spatial reuse. In order to identify the most suitable solution for future wireless systems, we compared the aggregate throughput achieved by two types of cross-layer designs. While the first approach suppresses the interference by power control at the transmitter side, the second cancels interference at the receiver with a technique called multiuser detection. It turned out that applying power control as basis for cross-layer design in very high traffic density scenarios can result in even worse performance than applying no cross-layer design at all. The gains achieved by the multiuser detection based cross-layer design were shown to be based on the interaction between physical and MAC layer, and not only on the more advanced physical layer technique. However, to investigate the provided quality of service, also other criteria have to be taken into account. Thus, in this paper, we investigate delay and fairness for both cross-layer designs. We show that power control based cross-layer design leads not only to lower aggregate throughput, but also to a lower offered quality of service.