The multiply-detected macrodiversity scheme for wireless cellular systems

The multiply-detected macrodiversity (MDM) scheme is proposed for wireless cellular systems. As opposed to the traditional macrodiversity schemes, in which at any time a signal from only one base station is selected, in the MDM scheme there is no selection, but all the received signals are detected, and a maximum-likelihood decision algorithm is employed to maximize the probability of correct decision. We study the performance of the MDM scheme and compare it with the performance of the traditional selection-based macrodiversity schemes. Depending on the propagation parameters, our results show that through the use of the MDM scheme, significant improvement in the bit-error rate (BER) can be achieved. For instance, if the outage probability is defined as BER above 10^-4 the outage is eliminated at least 45% of the time as compared with signal-to-interference (S/I) diversity, for a propagation attenuation exponent of 4.0 and shadowing standard deviation of 4.0 dB. Furthermore, as compared with the (S/I) diversity, the MDM scheme reduces, on the average, the BER at least two orders of magnitude throughout more than 60% of the cell area for a propagation attenuation exponent of 3.5, shadowing standard deviation of 4.0 dB and system loading of less than 50%