應用於高傳輸率4X4 MIMO-OFDM系統之軟式多輸入輸出解碼器與系統效能驗證

Soft-Output MIMO Detector and System Verification for High-Throughput 4x4 MIMO-OFDM System

駱柏丞(Po-chen Lo)

指導教授 ： 蔡佩芸

國立中央大學/資訊電機學院/電機工程學系/碩士(2014年)

摘要

本論文將介紹應用於室內的多輸入多輸出正交分頻多工調變高傳輸率無線通訊系統之相關設計。外發送機採用渦輪編碼來提升系統效能，而內發送機支援4根傳送天線、64-QAM星座圖及512、256、128三種不同快速傅立葉轉換點數的子載波模組。而內接收機的部分整合了同步偵測、通道估測以及多輸入輸出訊號的解碼三種功能區塊，而多輸入輸出訊號的解碼器為了配合外接收機所使用的渦輪解器，我們設計了能傳遞軟值的非固定K值K-Best球面解碼器，並結合ODE演算法下所產生的捨棄路徑來改善系統效能，此外，我們還針對捨棄路徑與效能的關係做分析，並提出了獨立式路徑選擇法與合併式路徑選擇法兩種不同的方法來減少捨棄路徑部分的硬體的複雜度，獨立式路徑選擇法擁有較低的複雜度，並且硬體實做較為簡單；合併式路徑選擇法則有較好的效能。在硬體實現的部分則採用整體複雜度較低且擁有不錯效能的獨立式路徑選擇。本論文的最後整合了內外發送機，並在TGn的B、C、D通道模型下做系統效能的模擬，其中在空間相關性較低的通道模組中能得到較佳的效能。
　　在晶片國家型計畫中，我們將收發機燒錄至計畫開發的FPGA板中，並使用計畫設計的RF天線做資料的傳送與接收，最後成功的量測到符元邊界偵測與通道估測的結果。

關鍵字

球面解碼器 ； 軟輸出 ； 渦輪解碼器

並列摘要

In this thesis, implementation of a MIMO-OFDM transceiver for indoor high throughput wireless communication systems is presented. Turbo encoder at the outer transmitter is used for improving performance. The inner transmitter supports 4 antennas, 64-QAM constellation and three operation models for different numbers of subcarrier (512, 256 and 128 point). At inner receiver, three main function block of synchronization, channel estimation and MIMO detection are implemented. To support Turbo decoding in the outer receiver, we design a soft-output K-Best sphere decoder. Which uses discard paths to improve the performance of system. Observing analyzing the relationship between the number of discard paths and performance, we propose independent path selection method and merged path selection method to reduce the complexity of discard paths. Independent path selection method has lower complexity and is suitable for hardware implementation. Merge path selection method has better performance. In the hardware implementation, we choose the Independent path selection method because of low complexity and good performance. In the end, we integrate inner and outer transceiver, and simulate the system performance in TGn channel model.
　　 In the project, we download the transceiver design into the FPGA, and integrate the RF analog frount-end. Finally we measure the signals of symbol boundary detection and channel estimation.

並列關鍵字

sphere decoder ； soft-output ； turbo decoder

參考文獻

[1] Chunhui Ju, Jun Ma, Chengzhi Tian, and Guanghui He, “VLSI Implementation of An 855 Mbps High Performance Soft-output K-Best MIMO Detector,” IEEE Circuits and Systems (ISCAS), pp. 2849-2852, May 2012.

[2] Meng-Yuan Huang and Pei-Yun Tsai, “Toward Multi-Gigabit Wireless: Design of High-Throughput MIMO Detectors with Hardware-Efficient Architecture,” IEEE Transactions on Circuits and Systems I: Regular Papers, vol. 61, pp. 613-624, Feb 2014.

[3] Patel D., Smolyakov V., Shabany M. and Gulak P. G., “VLSI Implementation of a WiMAX/LTE Compliant Low-Complexity High-Throughput Soft-Output K-Best MIMO Detector,” Proceedings of 2010 IEEE International Symposium on Circuits and Systems (ISCAS), pp. 593-596, May 2010.

[4] B. M. Hochwald and S. ten Brink, “Achieving near-capacity on a multiple-antenna channel,” IEEE Transactions on Communications, Vol. 51, No. 3, pp. 389-399, Mar 2003.

[5] Z. Guo and P. Nilsson, “Algorithm and implementation of the K-Best sphere decoding for MIMO detection,” IEEE Journal on Selected Areas in Communications, Vol. 24, No. 3, pp. 491-503, March 2005.