空間多路多輸入多輸出預編碼廣義分頻多工系統下低複雜度最小均方誤差-平行式干擾消除之迭代偵測器

Abstract

近年來，因其靈活性及其低帶外發射（Out-of-Band Emission, OOBE）的特性，廣義分頻多工（Generalized Frequency Division Multiplexing, GFDM）系統被推出用以替代正交分頻多工（Orthogonal Frequency Division Multiplexing, OFDM）。另外，在未來無線網路中，多重輸入輸出（Multiple-Input Multiple-Output, MIMO）將會是很重要的技術。然而因為是非正交傳輸波形，多輸入多輸出廣義分頻多工（MIMO GFDM）系統需要面臨符元間干擾（Inter-Symbol Interference, ISI）、載波間干擾（Inter-Carrier Interference, ICI）和天線間干擾（Inter-Antenna Interference, IAI）。在本論文中，我們採用最小均方誤差-平行干擾消除（Minimum Mean Squared Error with Parallel Interference Cancellation, MMSE-PIC）的接收器來處理空間多路（Spatial Multiplexing）多輸入多輸出預編碼廣義分頻多工（MIMO Precoded GFDM）系統的訊號和干擾，並透過提出的預編碼矩陣（Precoder Matrix）簡化偵測器（Detector），以及透過資源分配（Resource Allocation）更進一步降低錯誤率（Error Rate）。藉由我們的方法來實現最小均方誤差-平行干擾消除除了有比較低的錯誤率外，其複雜度和過去用在傳統多輸入多輸出廣義分頻多工的研究幾乎相同。實驗結果顯示，我們提出的設計擁有較低的錯誤率，但有較高的帶外發射。

In recent year, generalized frequency division multiplexing (GFDM) was proposed as an alternative waveform to orthogonal frequency division multiplexing (OFDM) due to flexibility and low out-of-band emission (OOBE). Besides, multiple-input multiple-output (MIMO) techniques are significant for future wireless networks. However, as a non orthogonal transmission scheme, MIMO GFDM system suffers from inter-symbol interference (ISI), inter- carrier interference (ICI) and inter-antenna interference (IAI). To cope with multiple kinds of interference, interference cancellation algorithms have been explored in the past. In this thesis, we implement iterative minimum mean squared error with parallel interference cancellation (MMSE-PIC) receiver structure in spatial multiplexing MIMO precoded GFDM system, and propose the method with better error performance, which includes the proposed precoder and the proposed set of subsymbol indices. Proposed precoder matrix simplifies the detector, and the proposed set of subsymbol indices can further improve error performance. The complexity of the proposed method is nearly the same as in previous work in conventional MIMO GFDM. Simulation results show that proposed method has visibly better error performance but lower spectral property in terms of OOBE.