Throughput/Delay Measurements of Limited Feedback Beamforming for Indoor Wireless Networks

Authors:

Robert C. Daniels, Ketan Mandke, Kien T. Truong, Scott M. Nettles, and Robert W. Heath, Jr.

Reference:

Under revision for submission to IEEE Transactions on Vehicular Technology.

Abstract:

In this paper we observe the tradeoff between throughput and feedback delay of limited feedback beamforming in indoor wireless channels with a practical MIMO-OFDM prototype. Past results are largely based on simplified models of the wireless channel. Unfortunately, wireless channel models may not accurately represent the complexities in a real wireless channel such as frequency offset, phase noise, and ambient interference. Furthermore, system impairments, including channel estimation error and synchronization error, only exacerbate the problem of modeling a real wireless system. One such analytical result predicts the performance of limited feedback beamforming as an exponential function of feedback delay. This analytical result has been confirmed through Monte Carlo simulation under Rayleigh fading channel models. Through rigorous measurements and experimentation this paper both evaluates the performance of limited feedback beamforming under feedback delay and confirms the accuracy of the analytical results. Moreover, we give some insights into the methodology for conducting such experiments.

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