1229981 玖、發明說明： 【發明所屬之技術領域】 本發明係關於一種多載波通訊系統接收機，特別是一 種負責接收多載波通訊系統中之信號，並可充分使用通道容 量，藉以達到高速率資料傳輸之多載波通訊系統接收機。 【先前技術】 由於現今網際網路的盛行，通訊系統所需的傳輸速率也 隨之大幅增加，而多載波通訊系統則可提供高傳輸速率的傳 輸，其動作原理係將通道有效頻寬分成許多彼此平行、獨立 的頻道，使得資料序列即可以不同頻率的載波分散傳輸，並 可將每一載波傳遞的資料位元數依通道的狀況作最佳化調 整，且在雜訊較少的頻率上，其載波所傳遞的位元數較多， 反之則較少，若能有效充分運用傳輸通道的頻寬，即可達到 傳輸速率的提升，亦可防止環境雜訊的影響。 多載波通訊系統的傳送信號係以碼框（frame)為單位，並藉 由通道之特性，當傳送信號經過通道時，信號在不同頻率會 產生不同的振幅衰減和相位延遲，使得接收端所接收的信號 難以辨識重建。針對此現象，通常會在傳送信號中放入週期 前置信號（為原碼框的部分資料，長度為^ )，以組成一新的 碼框，用來減低碼際干擾（Intersymbol Interference，ISI)，並使用通 道等化器（channel equalizer)來補償通道對信號的影響，使傳輸信 號能正確解調解碼，而通道等化係利用時域等化器 1229981 (Time-domain EQualizer，TEQ)以及頻域等化器（Frequency-domain EQualizer，FEQ)兩階段方法，以補償通道失真，且一般通常會使 用數位調整式濾波器（adaptive filter)來實現等化器架構；該時域 等化器（Time-domain EQualizer，TEQ)具有使脈衝響應分布長度小 於或等於週期前置的長度；該頻域等化器（Frequency-domain EQualizer，FEQ)係在修正通道與時域等化器所造成的相位與振 幅的失真。 其中，該時域等化器之操作方法係利用傳送一已知的週 期性訓練訊號’做為接收端的等化器訓練，並於接收端執行 最小平方和適應性演算法（Least Mean Square，LMS)，以滿足 h«w㈨=5(η_Δ )*b㈨關係。其中該岭)為通道脈衝響應， 為時域等化器的調整式濾波器係數，3 ~為一脈衝函數，△ 為時間延遲’ b㈨為一長度（^ +1)的任意波形訊號，且在最小 平方和適應性演算法運算前需先指定一特定的△，並於運算 時，在每一個取樣時間點比較上式中等式兩邊的結果，並更 新和b㈨的數值，以求得特定△的LMS解。此一特定之 △可在每次遞增後，重新帶入演算法中以求得所有延遲時間 的w㈣最佳解，或採用通道的脈衝響應最大值為△值代入求 得w»解。 經由通訊理論得知，最佳的通道延遲時間為通道的群組 延遲（gmupdelay)，在多裁波通訊系統中則為平均群組延遲，但 1229981 群組延遲所需的微分運算（d@ Μω )並不適合於數位訊號處 理，所以△若採用通道的脈衝響應最大值，不易求得最 佳解，若逐一代入△，則計算時間過長，且平均群組延遲又 不易計算，以及計算並更新〜㈨和的運算無法在一個取樣 時間點完成。 為取得前述碼框的開頭，須比較時域等化器等化後的接 收信號在哪一取樣點後的V長度區間内，其通道脈衝響應的 月里最大，因時域等化器通常無法完全消除碼際干擾，若每 間隔一取樣點計异其後區間的能量，不會有明顯的能量差 異’所以碼框邊界偵測器不易判斷碼框的開頭，以及正確地 將碼框對應至多載波解調變器的輸入，且同時無法進行頻域 等化器訓練動作。 再者’當頻域專化器於初始化時，Hpeq_n 一般採用LMS 演算法中所求的b»，將B(b㈨的頻域表示）取各載波之反矩 陣’但時域等化器未能將碼際干擾完全消除，因此b⑻不全 然等效的結果。 由此可見，上述習用通訊系統接收機仍有諸多缺失，實 非一良善之設計者，而亟待加以改良。 本案發明人鑑於上述習用通訊系統接收機所衍生的各項 缺點’乃亟思加以改良創新，並經多年苦心孤詣潛心研究 後，終於成功研發完成本件多載波通訊系統接收機。 【發明内容】1229981 发明 Description of the invention: [Technical field to which the invention belongs] The present invention relates to a receiver of a multi-carrier communication system, particularly a receiver for receiving signals in the multi-carrier communication system, and can make full use of channel capacity to achieve high-speed data Multi-carrier communication system receiver for transmission. [Previous technology] Due to the prevalence of the Internet today, the transmission rate required by communication systems has also increased significantly, and multi-carrier communication systems can provide high transmission rates. Its operating principle is to divide the effective bandwidth of the channel into many Parallel and independent channels allow data sequences to be dispersedly transmitted on different frequency carriers, and the number of data bits transmitted by each carrier can be optimally adjusted according to the condition of the channel, and on frequencies with less noise The number of bits transmitted by its carrier is large, otherwise it is small. If the bandwidth of the transmission channel can be effectively used, the transmission rate can be increased, and the influence of environmental noise can be prevented. The transmission signal of the multi-carrier communication system is based on the code frame (frame) and the characteristics of the channel. When the transmission signal passes through the channel, the signal will have different amplitude attenuation and phase delay at different frequencies, so that the receiving end receives Signals are difficult to identify and reconstruct. In response to this phenomenon, a periodic preamble signal (part of the original code frame with a length of ^) is usually placed in the transmission signal to form a new code frame to reduce intersymbol interference (ISI). Channel equalizer is used to compensate the influence of the channel on the signal, so that the transmission signal can be correctly demodulated and decoded. The channel equalizer uses the time-domain equalizer 1229981 (Time-domain EQualizer, TEQ) and the frequency. Frequency-domain EQualizer (FEQ) is a two-stage method to compensate for channel distortion. Generally, an digital filter is used to implement the equalizer architecture. The time-domain equalizer (Time -domain EQualizer (TEQ) has the length of the impulse response distribution less than or equal to the length of the period lead; the Frequency-domain EQualizer (FEQ) corrects the phase and phase caused by the channel and time-domain equalizer. Distortion of amplitude. The operation method of the time domain equalizer is to send a known periodic training signal as the equalizer training at the receiving end, and perform a least square and adaptive algorithm (LMS) at the receiving end. ) To satisfy the relationship h «w㈨ = 5 (η_Δ) * b㈨. Where the ridge) is the channel impulse response, is the adjusted filter coefficient of the time domain equalizer, 3 ~ is a pulse function, △ is the time delay 'b㈨ is an arbitrary waveform signal of a length (^ +1), and The least square sum adaptive algorithm needs to specify a specific △ before the calculation, and during the calculation, compare the results on both sides of the above equation at each sampling time point, and update the value of and b㈨ to obtain the specific △ LMS solution. This specific △ can be re-introduced into the algorithm after each increment to obtain the optimal solution w for all delay times, or the maximum value of the channel's impulse response can be used to obtain the solution w ». According to communication theory, the optimal channel delay time is the channel group delay (gmupdelay). In a multi-wavelength communication system, it is the average group delay. However, the differential operation (d @ Μω) required for the group delay of 1229981 ) Is not suitable for digital signal processing, so if the maximum value of the channel's impulse response is used, it is not easy to obtain the best solution. If you enter △ from generation to generation, the calculation time is too long, and the average group delay is not easy to calculate. The calculation of ~ ㈨ cannot be completed at one sampling time. In order to obtain the beginning of the aforementioned code frame, it is necessary to compare the sampling length of the received signal equalized by the time domain equalizer in the V length interval after which the channel impulse response is the largest in the month, because the time domain equalizer usually cannot Inter-symbol interference is completely eliminated. If the energy of the subsequent interval is different at every sampling point, there will be no obvious energy difference. Therefore, it is not easy for the code frame boundary detector to determine the beginning of the code frame and correctly correspond to the code frame at most. The input of the carrier demodulator, and at the same time, it is impossible to perform equalizer training in the frequency domain. Furthermore, when the frequency-domain specializer is initialized, Hpeq_n generally uses b »in the LMS algorithm, and takes B (the frequency domain representation of b㈨) to take the inverse matrix of each carrier ', but the time-domain equalizer fails Intersymbol interference is completely eliminated, so b⑻ is not a completely equivalent result. It can be seen that there are still many shortcomings in the receiver of the conventional communication system, which is not a good designer and needs to be improved. In view of the various shortcomings derived from the conventional communication system receiver, the inventor of the present case has been eager to improve and innovate. After years of painstaking research, he finally successfully developed this multi-carrier communication system receiver. [Summary of the Invention]