運用多輸入多輸出正交分頻多工技術之下一代高速無線區域網路基頻接收機設計

Baseband Receiver Design for Next-Generation High-Throughput Wireless LAN with MIMO-OFDM Technology

丁姿吟(Zih-Yin Ding)

指導教授 ： 闕志達

國立臺灣大學/電機資訊學院/電子工程學研究所/碩士(2005年)

https://doi.org/10.6342/NTU.2005.10387

摘要

下一代高速無線區域網路IEEE 802.11n的制定已經開跑，其主要訴求乃是達到更高速的傳輸，以應付目前新穎多媒體應用的速度需求。在本論文中，參考IEEE 802.11n的提案，以多輸入多輸出正交分頻多工技術作為實體層技術，設定傳送端架構與封包格式等系統規格，並設計出下一代高速無線區域網路的基頻接收機。
內接收機的主要架構可分為初始同步、追蹤迴路與通道估計及資料回復。其中初始同步包括封包偵測、符元邊界粗估與細估、分數載波頻率的估計，論文中將提出對雜訊有強健抵抗能力的符元邊界細估方式；追蹤迴路包括殘餘分數載波頻率偏移與取樣時脈偏移的聯合估計；通道估計則是利用兩天線傳送互相正交的訓練碼，得到最小方差估計。資料回復有兩個部份：多輸入多輸出訊號解碼與軟性解對應。多輸入多輸出的解碼方式與傳送模式有關，傳輸模式則依照傳送端是否具有通道資訊而調整，當傳送端具有通道資訊時，可在傳送端作前置處理，使接收端可分別對各路傳送資料進行偵測，降低了接收機複雜度。多輸入多輸出訊號解碼的結果送入軟性解對應器，計算每個位元的bit metric，以作為軟性決策維特比解碼器的輸入。
除了接收機的架構設計外，論文中也提出了接收端各功能方塊的硬體電路設計並以Novas Debussy作模擬與功能驗證。

關鍵字

多輸入多輸出 ； 正交分頻多工 ； 無線區域網路

並列摘要

The establishment of the next-generation high throughput wireless LAN, IEEE 802.11n, has started. It is a standard which aims to provide high throughput transmission for the demand of several novel multimedia applications. In this thesis, a base band receiver for next generation wireless LAN is proposed with the transmitter architecture and packet format according to the proposal of IEEE 802.11n.
The inner receiver can be divided into several parts: initial synchronization, tracking loop, channel estimation and data recovery. The initial synchronization includes packet detection, coarse and fine symbol boundary estimation, fractional carrier frequency offset estimation. A fine symbol boundary estimation which is robust to channel noise is introduced. The tracking loop includes joint estimation of residual fractional carrier frequency offset and sampling clock offset. The receiver exploits the orthogonal training sequence to find a set of least square error estimation of the channel. The data recovery is composed of MIMO signal decoding and soft demapping. The method of MIMO signal decoding is related to transmission mode which is adjusted depending on whether the transmitter has channel information. When the transmitter owns accurate channel information, the transmitted signal is pre-processed before transmitting and then the multiple transmitted streams can be detected independently. Therefore the complexity of receiver can be reduced. The MIMO signal decoding result is sent to soft demampper to calculate bit metrics which are the input of soft decision Viterbi decoder.
In addition to architecture design of receiver, the circuit design of all functional blocks which have been verified with Novas Debussy are also presented.

並列關鍵字

MIMO ； OFDM ； wireless LAN

參考文獻

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