Performance of multicell joint processing planar cellular uplink in the presence of relay nodes

In this paper we compare the uplink performance of various deployment scenarios in the planar (hexagonal) cellular system where the received signals at multiple cells are jointly processed by a central processor. A mathematical model of the planar cellular system is presented and its performance metric is based on information theoretic sum rate, and group rate share. The system deployment is as follows; the density of the base station is decreased, relay node replaces alternate base stations and in the last scenario, alternate bases stations are removed while the left over base stations are equipped with an additional antenna. It is observed that reduction in the density of base stations resulted in reduction in the achievable sum rate and makes the group rate unfair. The introduction of additional antenna resulted in an improvement in the rate (compared with the reduction in density scenario) without any improvement in group rate fairness to cell user at the cell edge. The replacement of base stations with relay node and the implementation of orthogonal amplify and forward scheme resulted in a reduction in the achievable sum rate however it produced a significant improvement in group rate fairness. The result suggest that relay deployment in multicell joint processing system does not improve the sum rate of the system rather it improves the rate share for cell edge users making the user rate distribution fairer.