Adaptive beamforming techniques for a frequency-hopped QAM receiver

Adaptive beamforming (ABF) provides wireless communication systems with larger service capacity and higher link quality through frequency reuse and co-channel-interference rejection. The issues of realizing ABF on a frequency-hopped (FH) QAM portable receiver in PCS applications are investigated. Considerations include the complexity of the receiver hardware, processing speed and power consumption for VLSI implementation. A possible single-chip structure with the capability of real-time tracking is selected from several structures. Also, we propose that by adding memory in the beamformer to store and restore the converged beamforming weights in each FH period, the system is able to improve the system performance and reduce the hardware complexity. The simulation results show that in an environment which contains 12 interferers with a signal-to-interference-and-noise ratio (SINR) of -14.31 dB, the proposed system can produce an output of SINR of 20.75 dB with 5 array elements. It is concluded that the combined techniques of ABF and FH can provide effective jamming or co-channel-interference protection in wireless communications.