利用移相器實現混合預編碼器在毫米波通訊

Abstract

在本論文中，考慮在毫米波的通訊環境中設計預編碼器，由於在射頻 的硬體成本比較高，所以利用移相器來做為實現，提出了三種結構在 移相器的角度還沒被量化時皆能實現最佳的預編碼器，在論文中考慮 移相器的角度經過量化後的影響，並分析了三種架構的量化誤差值。 實驗結果顯示即時在量化位元很小的情況下，三種架構所表現出來的 效能有很突出的表現。

In this thesis, we consider hybrid precoding and combining for millimeter transmission wave transmission with large antenna arrays point to point. Due to the high cost of RF chains, phases shifters are widely used to implement the RF beamforming. It is shown recently that the optimal unconstrained precoder can be implemented using only phase shifters. We proposed three schemes for implementation of beamforming weights using the phase shifters. These three schemes yield the same performance as optimal full digitally precoder when the phase shifters are of infinite resolution. This is done by implementing each beamforming weight using two phase shifters. However the performance differ upon phase quantization, we analyze the quantization error on the beamforming weight when the phase shifters are quantized for each proposed case. The analysis is done for the case of high resolution, but the results are accurate even for low resolution quantization as experiments have demonstrated. The simulation show that, with a low quantization resolution, the proposed hybrid precoder can achieve a performance close to that of the full digital precoder that has a dedicated RF chain for each antenna.