A simple scheme to improve the performance of your cellular system

The stochastic nature of wireless communication that manifests itself by the fading processes leads the designers of wireless networks to over-engineer their designs. This random behavior can, however, be reduced by diversity methods. For example, Rayleigh fading can be mitigated by microdiversity and the effects of shadow fading can be reduced by macrodiversity techniques. In this paper, we advocate the use of a macrodiversity scheme based on signal-to-interference ratio, in combination with postdetection combining. This scheme has been termed multiply-detected macrodiversity (MDM). We discuss the sources of the improvement and demonstrate that the MDM scheme yields a considerable gain over the traditional macrodiversity scheme that is based on selection of the strongest signal path. Application of the MDM scheme in practical wireless networks results in reduction in the BER throughout over 50% of the system coverage.