Joint MMSE beamforming with SIC for an overloaded array system

We propose a new signal extraction method that combines MMSE beamforming with successive interference cancellation (SIC) for an overloaded antenna array system. By an overloaded array system, we mean that the number of desired signals exceeds the number of distinct antenna elements, often by a significant amount. We evaluate the performance of the proposed signal extraction method through the use of bit error rate (BER) simulation. The simulation results show that the new signal extraction method can increase the number of users that can be supported in an airborne communication environment. We also evaluate the effects of directional antenna patterns on the performance of the proposed signal extraction method. Performance results for an 8 element antenna array show that the proposed signal extraction method with a 60° half-power beam width (HPBW) directional pattern can support up to 16 users (twice as many as number of antenna elements) and a 30° HPBW directional pattern can support up to 24 users (three times as many as number of antenna elements).