Capacity Study of Virtual MIMO Uplink OFDMA Cellular System with Cochannel Interference

Cochannel interference has been the bottleneck to the capacity of cellular network. To solve this issue, a virtual multiple-input multiple-output (MIMO) system can be constructed for the uplink OFDMA cellular system. However, if multiple cochannel MIMO clusters are used, they will still interfere with each other. Capacity of this virtual MIMO system in cellular networks with cochannel interference is derived and simulated. The influence of some parameters to the system capacity are studied, including path loss component, transmit power, the radius of cell and the number of antennas in base stations. Simulation results show that if only the first 1 neighbor layer of cochannel cells are considered, the virtual MIMO capacity will be greatly larger than that of the single-input single-output (SISO) system with universal frequency reuse. However, the cochannel interference can greatly reduce the virtual MIMO capacity in the uplink cellular system compared with the interference free environment. Thus interference cancellation techniques are required to be developed in the future.