Multiple-Antenna Post Low Noise Amplifier RF Combining

In this paper we propose the superheterodyne receiver beamforming architecture called post-low noise amplifier RF combining (PLRC) to reduce the power consumption by using the single analog-to-digital converter (ADC). The RF chains in our proposed schemes includes the same number of the low noise amplifier (LNA) and the discrete-level phase shifters as the number of antennas followed by the single chain which consists of combiner, mixer, IF and the analog-to-digital converter (ADC). We propose simple channel estimation techniques based on the codebook stored in the baseband. We show from our some selected simulations that, when the exact phase information is available, the loss of beamforming gain of our proposed PLRC is not significant in terms of both signal-to-noise ratio (SNR) and bit error rate compared to the conventional baseband beamforming techniques while the power consumption of our proposed scheme can be much saved by using the single RF chain and single ADC. In addition, even for the use of the discrete phase level, the performance loss is negligible.