Enhancing Wireless Capacity in Heterogeneous Networks with Interference Power

We consider the problem of wireless multicasting through multiple-input multiple-output (MIMO) heterogeneous networks in which macro and pico base stations communicate with multiple macro and pico users, respectively. At first, we calculate the multicast capacity of macro users (MUs) and pico users (PUs), and investigate the impact of interferences on it. Then, we use zero-forcing (ZF) precoding at a relay to enhance the multicast capacity of MUs and PUs removing the impact of interferences. Finally, we propose a scheme to improve the multicast capacity of MUs and PUs making use of interference energy that already exists in the communication medium employing selective precoding at the relay. In the proposed scheme, interference provides an additional source of energy that enhances multicast capacity of MUs and PUs without the need to increase the transmitted power. Our results show that exploiting free interference power, the performance of wireless multicasting through the heterogeneous networks can be improved without affecting the performance of any base station by the other base station.