Performance analysis for cross-tier cooperation in heterogeneous cellular networks: A stochastic geometry approach

To meet the ever-increasing data traffic demand, heterogeneous cellular networks (HCNs) are to be deployed for wireless communication and coordinated multipoint (CoMP) is thought to be desirable to further improve the performance of HCNs. This paper considers the problem of base station (BS) cooperation in the downlink of HCNs. A novel and flexible cross-tier cooperative scheme is proposed in the paper. Our cooperative scheme allows BSs in each tier to cede their original cell range to cooperative region, thus extent the cooperative region, where users are better served through cross-tier cooperation. Using tools from stochastic geometry, we derive expressions for the outage probability as well as average ergodic rate of our scheme. Simulation results are given to verify the accuracy of our analysis and numerical results indicate that our cooperative scheme reduces the outage probability by about 21.2% and increases the average ergodic rate by about 9.2%, compared with the traditional maximum reference signal received power (RSRP) scheme.