TWI244275B - A rake receiver employable in multipath environment and method for mitigating the multipath interference - Google Patents
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12976twf.doc/006 玖、發明說明： 【發明所屬之技術領域】 本發明是有關於一種無線通訊系統，比如但不受1¾% 無線區域網路（wireless local area network，WLAN)，意护 別是有關於可以減低由於多路徑傳播而產生之字符碼 (Intra-Symbol)和字符碼中（inter-symbol)失真的〜镇 802.11b 互補碼移位鍵（Complementary Code Keying，以卞 簡稱CCK)接收器(Receiver)。 【先前技術】 偉伯斯徹（Webster)等人之美國專利公開案_ 2001/0036223揭露了一種耙式（以下稱RAKE)接收器，其 用於具非常短字元碼（Codeword)長度之直接展頻（direet spread spectrum)信號之室內多路徑WLAN中。偉伯斯徹 的圖6、7、8以及10顯示的RAKE接收器中，在接收器 通道匹配濾波器（Channel Matched Filter，簡稱CMF)與字 元碼關聯器間之信號處理路徑中具有一嵌入式位元基底 (Chip-Based)回授決定等化器（Decision Feedback Equalizer，以下簡稱DFE)結構。該回授決定等化器用於 抵消字符碼間干擾（inter-symbol interference，簡稱ISI(亦 即CCK字元碼間之排放過度(bleed-over))。12976twf.doc / 006 发明, Description of the invention: [Technical field to which the invention belongs] The present invention relates to a wireless communication system, such as but not limited to 1¾% wireless local area network (WLAN). About the 802.11b Complementary Code Keying (hereinafter referred to as CCK) receiver which can reduce the character code (Intra-Symbol) and inter-symbol distortion caused by multi-path propagation. (Receiver). [Prior Art] US Patent Publication of Webster et al. _ 2001/0036223 discloses a rake (hereinafter referred to as RAKE) receiver, which is used for direct communication with very short codeword length. In indoor multipath WLANs with a spread spectrum signal. In the RAKE receiver shown in Figures 6, 7, 8, and 10 of Weberscher, there is an embedding in the signal processing path between the receiver Channel Matched Filter (CMF) and the character code correlator. Chip-Based feedback decision equalizer (DFE) structure. The feedback decision equalizer is used to offset inter-symbol interference (ISI for short) (that is, bleed-over between CCK character codes).
偉伯斯徹之圖12-14顯不字符碼內位兀干擾（Intra-Symbol Chip Interference，簡稱ICI)抵消器，其設計成抵 消在802.11b CCK解碼器中之由使用長度複變操作（乘法 與加法）之後游標(post-cursor·)所產生之字符碼內位元干擾 ICI，包括各字元碼（總計有高達256個字元碼）之一 DFE 976tvvf.doc/006 I244275 旋積（convolution)方塊與一字元碼關聯方塊。64或256個 字符碼內位元干擾ICI輸出之各輸出從一獨立處理路徑獨 立計算。 在偉伯斯徹之圖12中，對各字元碼(總計有高達256 個字元碼）而言，需要三個基本建構方塊：⑴一 DFE旋積 方塊1220,利用各字元碼（8個複數位元，標示爲〇w#Kchip) 間之複數旋積與高達8個的複數DFE標籤(tap)來計算字 元碼關聯器1230前之字符碼內位元干擾iCI之逐位元代 表；（ii)一逐位元減法器1210，從方塊1220之輸出減去各 接收的8個複數位元（方塊1203);以及(iii)一字元碼關聯 器1230，計算各字元碼（8個複數位元）與減法器1210之輸 出8個複數位兀間之關聯性。所有運算都是複數的，且被 各字元碼所需要。簡言之，256個字符碼內位元干擾iCl 偏差輸出1212在方塊1220內獨立計算，在方塊1210處 進行平行減法，接著從該字元碼關聯器1230找到2%個 關聯輸出。因爲各字元碼關聯器1230之輸入1223在經字 符碼內位元干擾ICI偏差校正後變得不同，此架構避免快 速瓦許轉換(Fast Walsh Transform，以下簡稱FWT)以共同 (jointly)與有效地計算所有CCK字元碼之CCK關聯性。 在偉伯斯徹之圖13之另一實施例中，對於各字元碼（共 有64個字元碼），需要兩個基本建構方塊（具有上述之相同 功能）··⑴一 DFE旋積方塊1340與（ii) 一字元碼關聯器 1330。所需之DFE方塊與關聯方塊之數量從256減少爲 64。經由複數運算，方塊1330之64個字符碼內位元干擾 ICI輸出展開成256個字符碼內位元干擾ICI輸出。相比 1244275 12976twf.doc/006 於圖12，此架構計算後-CCK字元碼關聯器校正1360之 字符碼內位兀干擾ICI偏差。因而，利用64元件快速瓦 許轉換器Π2〇與1至4展開方塊1350，可有效實現能共 同與有效計算CCK關聯性之字元碼關聯器。然而，利用 複數旋積134〇與複數關聯1330來先計算各後關聯字符碼 內位元干擾ICI偏差。接著利用1至4展開方塊1350來 產生全部的256個後關聯字符碼內位元干擾ICI偏差。接 著從方塊1350之相關256個關聯器輸出減去這些後關聯 字符碼內位元干擾ICI偏差。爲實施此接收器架構，需要 能獨立操作之64個複數旋積1340與複數字元碼關聯器 1330。 在偉伯斯徹之圖Μ之又一實施例中，對於各字元碼(共 有256個字元碼）需要兩個基本建構方塊(具有上述之相同 功能）：⑴一 DFE旋積方塊1440與（Π)—複數字元碼關聯 器1430。偉伯斯徹描述了，可預計算與預儲存DFE標籤。 再次，在方塊1440獨立計算256個字符碼內位元干擾ICI 輸出，接著在方塊1430之輸出找到256項關聯性。 總結來說，偉伯斯徹之架構需要一個位元基底的DFE 來做爲由前一字符所產生之字符碼間干擾ISI的抵消裝 置。另外，偉伯斯徹之架構需要大量複雜硬體與複數運算 之大量運算（複數旋積與複數關聯所需之複數乘法與加 法）。因此，爲實施偉伯斯徹之第12-14圖之實施例，需要 大量功率消耗，複雜的硬體與長處理時間。 在20〇2年11月7號所申請，全名爲、具有快速多路 徑干擾加密器（Fast Multipath Interference Cipher，以下簡 1244¾¾ twf.doc/006 稱 FMIC)之封包基底（Packet-Based)自由乘積 (Multiplication-Free) CCK解調器〃（美國專利序案號第 10/289,749號）中，此發明所描述的接收器係被提供給一個 創新的FMIC以減低字符碼內位元干擾ICI，如美國專利 序號第10/289,749號的圖2所示，所有256個CCK字碼 的字符碼內位元干擾ICI，能夠由一個創新的FMIC方塊 在第一運算模式（Mode 1)下連帶地且有效地計算出來。而 另一個運算模式(Mode 2)，在CCK解碼器方塊內，係由CCK 關聯器輸出中減去相對應之字符碼內位元干擾ICI。此 FMIC方塊具有類似於CCK關聯器的架構，可實現多路徑 轉換(Fast Multipath Transform，以下簡稱 FMT)，其利用 FWT以共同與有效地計算出CCK字碼間的相關性。雖然 在美國專利序號第10/289,749號所提出的接收器，能夠成 功地降低由於多路徑傳播（此多路徑傳播實質上並不在任 何附加的硬體上傳播)所產生的字符碼內位元干擾ICI，但 是其（而且尤其是FMIC)卻不能降低由於多路徑傳播而產 生之字符碼間干擾ISI。 【發明內容】 本發明的目的就是在提供一種CCK接收器，以有效 地降低字符碼內位元干擾ICI和字符碼間干擾ISI。 本發明的再一目的是提供一種CCK接收器，係利用 最簡單的運算來降低字符碼內位元干擾ICI和字符碼間干 擾 ISI。 本發明的又一目的是提供一種CCK接收器，可以使 用簡單的硬體結構，來降低字符碼內位元干擾ICI和字符 1244说 twf.doc/006 碼間干擾ISI。 爲達上述目的，本發明提供一種以目前CCK字符碼 降低多路徑干擾遭遇的方法，本發明所提供的方法，首先 依據用於目前CCK字符碼和下一 CCK字符碼之ICI校正 關聯輸出，來分別對應獲得用於目前CCK字符碼和下一 CCK字符碼之數個起始的候選者的集合。接下來，本發明 所提供的方法係對用於目前CCK字符碼之每一個候選者 的集合而言，係取得數個第一降低字符碼間干擾ISI關聯 輸出，其中因爲目前CCK字符碼而產生之字符碼內位元 干擾ICI和因爲下一 CCK字符碼而產生之字符碼間干擾ISI 均被校正。之後，本發明對目前CCK字符碼的每一候選 者和依據第一降低字符碼間干擾ISI關聯輸出而言，係取 得數個第二降低字符碼間干擾ISI關聯輸出，其中因爲前 一 CCK字符碼而產生之字符碼間干擾ISI被校正。然後依 據第二降低字符碼間干擾ISI關聯輸出，以解碼目前CCK 字符碼。 本發明也提供一種使用於多路徑環境之rake接收 器’本發明之RAKE接收器用來接收數個CCK字符碼， 並且這些CCK字符碼包括目前CCK字符碼、前一 CCK 子符碼和下一 CCK字符碼。本發明之RAKE接收器係包 括用來判斷通道脈衝響應的通道判斷裝置，以及用來接收 回饋標籤權値（Feedback Tap Weight)以及前饋標籤權値 (Feed"F〇rward Tap Weight)的FMIC偏差計算裝置。而其中 的回饋標籤權値和前饋標籤權値，係從通道判斷裝置所計 算出之數個多路徑干擾偏差中取得，又，這些多路徑干擾 I2442J7^wfd〇c/〇〇6 偏差係目前cck字符碼之字符碼內位元干擾ici的後關 聯表示。本發明之rake接收器也包括通道匹配濾波器 (Channel Matched Filter，簡稱CMF)，用來接收由通道判 斷裝置所產生之通道匹配濾波器標籤權値（CMF Tap Weight)，以及包括CCK關聯器，其用來接收通道匹配濾 波器之輸出，並且CCK關聯器係產生數個關聯輸出。本 發明之RAKE接收器更包括解碼器，其用來⑴從FMIC偏 差計算裝置中接收數個多路徑干擾偏差，用來降低目前 CCK字符碼所產生之字符碼內位元干擾ICI。（ii)從通道判 斷裝置接收前饋標籤權値和回饋標籤權値，以計算由前一 CCK字符碼和下一 CCK字符碼所產生之多路徑干擾偏差。 (iii)從CCK關聯器接收其關聯輸出，以降低由目前CCK 字符碼所產生之字符碼內位元干擾ICI，以及由下一 CCK 字符碼和前一 CCK字符碼所產生之字符碼間羊擾ISI。 爲讓本發明之上述和其他目的、特徵和優點能更明顯易懂，下文 特舉一較佳實施例，並配合所附圖式，作詳細說明如下。 【實施方式】 以下描述本發明之最佳實施模式。此描述非用於限制 本發明，只爲描述本發明實施例之一般原則。本發明之範 圍由申請專利範圍定義。在某些例子中，省略習知裝置， 元件，機構與方法以免模糊本發明之描述。 無線區域網路的標準格式係8〇2.llb。簡化之802.U 封包格式顯示於圖1中，其包含兩種操作模式。封包之序 言(Preamble)(模式丨）爲巴克(Barker)編碼式，而資料部份(模 式2)係以互補碼移位鍵作調變，以提供編碼後cck位元。 ;wf.doc/006 因爲不會同時操作此兩模式，所以可利用共享模式1與2 之硬體以降低硬體複雜度。 圖2係繪示依照本發明之接收器20之方塊圖。以下， 一開始先對接收器20中各方塊的功能加以描述。 802.1 1b傳輸器(Transmitter·)—次傳輸一個資料封包至 接收器20以進行處理。當傳輸CCK調變封包時，各8資 料位元經CCK編碼成8個複數位元（稱爲一個CCK字符碼 或是一個CCK字元碼），此8個複數位元由該802.11b傳 輸器逐位元地依序傳輸。此信號經過無線通道並到達 802.11b接收器（比如爲接收器20)。一般無線通道之特徵 在於多路徑傳播，因此會讓接收到之信號失真。此種多路 徑傳播和其問題，將會在下文之相關的圖5中再加以敘述。 因此’實施低成本與高性能之接收器以減輕多路徑失真是 非常重要的。 接收器20包括選擇器22,通道脈衝響應判斷裝置24、 FMIC偏差計算裝置36a、通道匹配濾波器(CMF) 28、CCK 關聯器模組36b和連接字符碼解碼器25。選擇器22係將 接收訊號送至兩條路徑中其中一條。在序言處理期間，選 擇器22選擇第一條路徑(模式1}，而當對接收CCK解碼 時，則連接第二條路徑(模式2)。 通道脈衝響應判斷裝置(CIR Estimation) 24的輸入耦 接至選擇器22,而其輸出耦接至FMIC偏差計算裝置(FMIC Bias Computation) 36a、通道匹配濾波器（CMF) 28和連接 字符碼解碼器（Joint Symbol Decoder*) 25。假設通道脈衝響 應判斷裝置24在一個封包(Packet)週期內其通道脈衝響應 11 1244¾¾ wf.doc/006 維持不變，並且在處理每一封包之序言的期間於模式1工 作。則在模式1操作的期間，通道脈衝響應判斷裝置24 利用巴克碼關聯來決定一個判斷的''通道脈衝響應〃（CIR， 又稱作 '多路徑強度曲線〃）。通道脈衝響應判斷裝置24 的其中一組輸出爲通道匹配濾波器CMF標籤權値。在第 四版的數位通訊（Digital Communications, Fourth Edition, J.G. Proakis，McGraw Hill，NewYork，1995，下文簡稱 ''Proakis")的第14章中說到，最佳的通道匹配濾波器CMF 標籤權値可以輕易第從判斷的通道脈衝響應中取得。而爲 了簡化硬體的架構，使用者也可以依據臨界標準(Threshold Criterion)來消除路徑上可以忽略的能量。通道脈衝響應判 斷裝置24的另一組輸出，係回饋FB標籤權値(以下記爲 B1、B2.....B7)和前饋FF標籤權値(以下記爲Fi、F2..... F7)，其分別對應包含了通道匹配濾波器的混合通道頻率響 應之後游標和前游標部分。這些標籤權値被⑴FMIC偏差 計算裝置36a用來計算FMIC偏差至連接字符碼解碼器 25,以及（Π)連接字符碼解碼器25用來計算因爲之前的CCK 字符碼和下一 CCK字符碼所產生之多路徑干擾。 在模式1中，FMIC偏差計算裝置36a所表現出來的 功能，係與美國專利序號第10/289,749號的FMIC方塊36a 相同。而在本發明中的FMIC偏差計算裝置36a之架構， 也可以與美國專利序號第10/289,749號中所繪示不同之 FMIC方塊的結構相同。在模式1期間，本發明內之FMIC 偏差計算裝置36a使用由通道脈衝響應判斷裝置24所提 供的前饋FF和後饋FB標籤權値當輸入，以共同地和有效 12 06 I244^77^wfdoc/0 地計算64(或32、或16、或8)個多路徑干擾。連接字符碼 解碼器25係在模式2中使用這些FMIC偏差，且如下所 述之有效的抵消字符碼內位元干擾ICI。這些由FMIC偏 差計算裝置36a所提供之多路徑干擾，係一般接收CCK 字符碼（8位元長）所產生之字符碼內位元干擾ICI的後關 聯表示。假設多路徑的輪廓在一個封包的週期內不會改 變。則每一個封包在模式1只會計算一次這些多路徑干擾。 稍待，這些多路徑干擾（以下記爲 α · /C7W = α · G (I +态Γ己㈨=〇，1，2，···，255))會在連接字符碼解碼器 25 從 CCK 關聯器模組（CCK Correlator Bank) 36b 的輸出， 扣除相對應之多路徑干擾値來補償字符碼內位元干擾ICI 所造成的影響時，在模式2中被使用到。而如美國專利序 號第10/289,749號的接收器，相同的硬體結構可以用來實 現模式1中之FMIC偏差計算裝置36a，以及模式2中之 CCK關聯器模組36b。換句話說，同一種硬體結構可以被 、、分享（Shared)〃 ’或是在兩個不同的時機被用到’且會有 兩種不同的功能表現。 在模式2的操作期間，通道匹配濾波器CMF 28會使 用由通道脈衝判斷裝置24所提供之通道匹配濾波器CMF 標籤權値，將通過多路徑通道之接收訊號的能量合倂。在 圖2中，通道匹配濾波器28的輸出係標示爲Rk。對第k 個CCK字元碼而言’每一個Rk包含了八個接收位元l>8k， r8k+i，r8k+2, r8k+3, r8k+4, r8k+5, r8k+6, r8k+7]。在多路徑通道制定 Rk的詳細敘述則如圖5所示’在以下的圖5中會有詳細的 相關敘述。 13 1297otwf.doc/006 詳細地說，一個CCK字元碼包含8個CCK位元係由 於1999年IEEE所制定之8〇2.lib的標準。在下文中，以 C = = 〇，1，··.，255}做爲 CCK 編碼本（Codebook)的標不’並 且已將會被用於標示CCK編碼本中第m個CCK字元碼。 第k個傳輸CCK字元碼係記爲ck :Figure 12-14 of Weberscher's Intra-Symbol Chip Interference (ICI) canceller, which is designed to cancel the length complex operation (multiplication and multiplication) in the 802.11b CCK decoder. Addition) After the cursor (post-cursor ·), the internal code of the character code interferes with ICI, including one of the character codes (up to 256 character codes in total). DFE 976tvvf.doc / 006 I244275 convolution A block is associated with a character code. Each output of the 64 or 256 character code interfering ICI output is calculated independently from an independent processing path. In Figure 12 of Weberscher, for each character code (up to 256 character codes in total), three basic building blocks are needed: a DFE convolution block 1220, using each character code (8 Complex bits, labeled as 〇w # Kchip) and up to 8 complex DFE tags (tap) to calculate the bit-by-bit representation of the interfering iCI in the character code before the character code correlator 1230; (Ii) a bitwise subtractor 1210, subtracting each of the eight received complex bits from the output of block 1220 (block 1203); and (iii) a character code correlator 1230 to calculate each character code (8 Complex bits) and the output of the 8 complex bits of the subtractor 1210. All operations are complex and required by each character code. In short, the bit interference iCl deviation output 1212 in the 256 character code is independently calculated in block 1220, and a parallel subtraction is performed at block 1210, and then 2% of related outputs are found from the character code correlator 1230. Because the input 1223 of each character code correlator 1230 becomes different after being corrected for bit interference ICI deviation in the character code, this architecture avoids Fast Walsh Transform (hereinafter referred to as FWT) to be jointly and effectively Calculate the CCK correlation of all CCK character codes. In another embodiment of FIG. 13 of Weberscher, for each character code (a total of 64 character codes), two basic building blocks (having the same function as described above) are required. A DFE convolution block 1340 And (ii) a one-character code correlator 1330. The number of DFE blocks and associated blocks required has been reduced from 256 to 64. Through complex operation, the 64-character code interfering ICI output of block 1330 is expanded into the 256-character code interfering ICI output. Compared to 1244275 12976twf.doc / 006 in Figure 12, after the calculation of this architecture, the -CCK character code correlator corrects the ICI deviation in the character code of 1360. Therefore, using the 64-element fast-wattage converter UI20 and 1 to 4 to expand the block 1350, a character code correlator capable of common and effective calculation of CCK correlation can be effectively implemented. However, the complex convolution product 1340 and the complex correlation 1330 are used to calculate the interfering ICI bias in each subsequent correlated character code first. 1 to 4 is then used to expand block 1350 to generate all 256 post-associated character code bit interference ICI biases. Then the sub-associated bits in the associated character code interfere with the ICI deviation from the relevant 256 correlator outputs of block 1350. To implement this receiver architecture, 64 complex convolutions 1340 and complex digital meta-code correlators 1330 that can operate independently are needed. In yet another embodiment of Weber's diagram M, two basic building blocks (having the same functions described above) are required for each character code (a total of 256 character codes): a DFE convolution block 1440 and ( Π)-complex digital meta code correlator 1430. Weberscher described pre-calculated and pre-stored DFE tags. Again, the 256-character bit interference ICI output is independently calculated in block 1440, and then 256 items of correlation are found in the output of block 1430. To sum up, the architecture of Weberscher requires a bit-based DFE as a cancellation device for the inter-character interference ISI generated by the previous character. In addition, Weberscher's architecture requires a large number of complex hardware and complex operations (complex multiplication and addition required for complex convolutions and complex numbers). Therefore, in order to implement the embodiment of Figs. 12-14 of Weberscher, a large amount of power consumption, complicated hardware and long processing time are required. Applying on November 7, 2002, the full name is the Packet-Based Free Product of the full name, which has a Fast Multipath Interference Cipher (Fast Multipath Interference Cipher (hereinafter referred to as FMIC) 1244¾¾twf.doc / 006). (Multiplication-Free) In the CCK demodulator (U.S. Patent Serial No. 10 / 289,749), the receiver described in this invention is provided to an innovative FMIC to reduce the interference of ICI within the character code, such as As shown in Figure 2 of U.S. Patent No. 10 / 289,749, the internal bits of the character code of all 256 CCK words interfere with ICI, and an innovative FMIC block can be used together and effectively in the first operation mode (Mode 1) Calculated. The other operation mode (Mode 2), in the CCK decoder block, is to subtract the corresponding character code bits from the CCK correlator output to interfere with ICI. This FMIC block has a structure similar to the CCK correlator, which can implement a Multipath Transform (FMT), which uses FWT to jointly and efficiently calculate the correlation between CCK words. Although the receiver proposed in US Patent No. 10 / 289,749 can successfully reduce the bit interference in the character code due to multipath propagation (this multipath propagation does not substantially propagate on any additional hardware) ICI, but it (and especially FMIC) cannot reduce the ISI of character-to-code interference caused by multipath propagation. [Summary of the Invention] The object of the present invention is to provide a CCK receiver to effectively reduce bit interference ICI and character code interference ISI within a character code. Still another object of the present invention is to provide a CCK receiver, which uses the simplest operation to reduce bit interference ICI and character code interference ISI within a character code. Another object of the present invention is to provide a CCK receiver, which can use a simple hardware structure to reduce the bit interference ICI and 1244 twf.doc / 006 inter-code interference ISI in a character code. To achieve the above object, the present invention provides a method for reducing multipath interference encounter with the current CCK character code. The method provided by the present invention first corrects the correlation output based on the ICI used for the current CCK character code and the next CCK character code. A set of several starting candidates for the current CCK character code and the next CCK character code are obtained correspondingly. Next, the method provided by the present invention is to obtain a number of first reduced inter-character interference ISI correlation outputs for each candidate set used for the current CCK character code, which is generated by the current CCK character code. The bit interference ICI in the character code and the interference ISI between the character codes due to the next CCK character code are corrected. After that, for each candidate of the current CCK character code and the ISI-associated output based on the first reduced inter-character code interference, the present invention obtains a number of second ISI-associated output with reduced inter-character code interference, because the previous CCK character The inter-code interference ISI generated by the code is corrected. Then according to the second reduction of the inter-character interference ISI correlation output to decode the current CCK character code. The present invention also provides a rake receiver used in a multi-path environment. The RAKE receiver of the present invention is used to receive several CCK character codes, and these CCK character codes include the current CCK character code, the previous CCK sub-symbol code, and the next CCK. Character code. The RAKE receiver of the present invention includes a channel judging device for judging a channel impulse response, and an FMIC deviation for receiving a feedback tap weight (Feedback Tap Weight) and a feed forward label weight (Feed " Forward Tap Weight). Computing device. The feedback label weight and feedforward label weight are obtained from several multipath interference deviations calculated by the channel judging device, and these multipath interference I2442J7 ^ wfd〇c / 〇〇6 deviations are currently The bits in the character code of the cck character code interfere with the post-association representation of ici. The rake receiver of the present invention also includes a Channel Matched Filter (CMF), which is used to receive the CMF Tap Weight generated by the channel judgment device, and includes a CCK correlator, It is used to receive the output of the channel matched filter, and the CCK correlator generates several correlated outputs. The RAKE receiver of the present invention further includes a decoder for receiving a plurality of multipath interference deviations from the FMIC deviation calculation device, and used to reduce the ICI of the bit interference in the character code generated by the current CCK character code. (Ii) Receive the feedforward label weight and feedback label weight from the channel judgment device to calculate the multipath interference deviation generated by the previous CCK character code and the next CCK character code. (iii) Receive its correlation output from the CCK correlator to reduce the interference of ICI in the character code generated by the current CCK character code, and the character code generated by the next CCK character code and the previous CCK character code Disturb ISI. In order to make the above and other objects, features, and advantages of the present invention more comprehensible, a preferred embodiment is exemplified below and described in detail with reference to the accompanying drawings. [Embodiment] The best mode for carrying out the present invention will be described below. This description is not intended to limit the invention, but to describe the general principles of the embodiments of the invention. The scope of the invention is defined by the scope of the patent application. In some examples, conventional devices, components, mechanisms and methods are omitted so as not to obscure the description of the present invention. The standard format of a wireless LAN is 80.2.llb. The simplified 802.U packet format is shown in Figure 1, which includes two modes of operation. The preamble of the packet (mode 丨) is Barker code, and the data part (mode 2) is modulated by the complementary code shift key to provide the encoded cck bits. ; wf.doc / 006 Because these two modes are not operated at the same time, the hardware of mode 1 and 2 can be shared to reduce the hardware complexity. FIG. 2 is a block diagram of a receiver 20 according to the present invention. In the following, the functions of the blocks in the receiver 20 will be described first. 802.1 1b Transmitter—Transmits one data packet to receiver 20 at a time for processing. When transmitting CCK modulation packets, each 8 data bits are encoded by CCK into 8 complex bits (known as a CCK character code or a CCK character code). The 8 complex bits are transmitted by the 802.11b transmitter. Sequential transmission bit by bit. This signal passes through the wireless channel and reaches the 802.11b receiver (for example, receiver 20). General wireless channels are characterized by multipath propagation, which can distort the received signal. This kind of multipath propagation and its problems will be described in the related Figure 5 below. It is therefore very important to implement a low cost and high performance receiver to mitigate multipath distortion. The receiver 20 includes a selector 22, a channel impulse response judgment device 24, an FMIC deviation calculation device 36a, a channel matched filter (CMF) 28, a CCK correlator module 36b, and a connection character code decoder 25. The selector 22 sends the reception signal to one of two paths. During preamble processing, the selector 22 selects the first path (mode 1), and when receiving CCK is decoded, the second path (mode 2) is connected. Input coupling of the channel impulse response judgment device (CIR Estimation) 24 It is connected to the selector 22, and its output is coupled to the FMIC Bias Computation 36a, the channel matched filter (CMF) 28, and the connection character code decoder (Joint Symbol Decoder *) 25. Assume the channel impulse response judgment The device 24 has a channel impulse response 11 1244¾¾ wf.doc / 006 within a packet period, and operates in mode 1 during the processing of the preamble of each packet. During the operation of mode 1, the channel impulse The response judging device 24 uses Barker code correlation to determine a judged `` channel impulse response '' (CIR, also known as a 'multipath intensity curve'). One of the outputs of the channel impulse response determination device 24 is a channel matched filter CMF Label rights. Digital Communications, Fourth Edition, JG Proakis, McGraw Hill, New York, 1995, hereinafter referred to as "Proakis " In Chapter 14 of Chapter), the best channel matching filter CMF label weight can be easily obtained from the judged channel impulse response. In order to simplify the hardware architecture, users can also use the threshold criteria (Threshold Criterion ) To eliminate the negligible energy on the path. The other set of outputs of the channel impulse response judging device 24 are feedback FB label weights (hereinafter referred to as B1, B2 ..... B7) and feedforward FF label weights The following are referred to as Fi, F2 ..... F7), which correspond to the back cursor and front cursor parts of the mixed channel frequency response including the channel matched filter. These label weights are used by the FMIC deviation calculation device 36a to calculate the FMIC deviation. To the connected character code decoder 25, and (Π) the connected character code decoder 25 is used to calculate the multipath interference caused by the previous CCK character code and the next CCK character code. In the mode 1, the FMIC deviation calculation means 36a The functions shown are the same as the FMIC block 36a of US Patent No. 10 / 289,749. The structure of the FMIC deviation calculation device 36a in the present invention can also be the same as that of US Patent No. 10 / 289,749 The structure of the different FMIC blocks shown in Figure 1 is the same. During Mode 1, the FMIC deviation calculation device 36a in the present invention uses the feedforward FF and feedback FB label weights provided by the channel impulse response determination device 24 as input, Calculate 64 (or 32, or 16, or 8) multipath interference with a common and effective 12 06 I244 ^ 77 ^ wfdoc / 0. The concatenated character code decoder 25 uses these FMIC deviations in mode 2 and effectively cancels out the interfering ICI in the character code as described below. These multi-path interferences provided by the FMIC deviation calculation device 36a are post-associated representations of the inter-bit interference ICI in the character code generated by generally receiving the CCK character code (8-bit long). It is assumed that the contour of the multipath does not change during the period of one packet. Then each packet will only calculate these multipath interferences once in mode 1. Wait a moment, these multipath interferences (hereinafter referred to as α · / C7W = α · G (I + state Γ ㈨ = 0, 1, 2, · · ·, 255)) will be connected to the character code decoder 25 from CCK The output of the correlator module (CCK Correlator Bank) 36b is used in mode 2 when the corresponding multipath interference 値 is subtracted to compensate for the impact of the bit interference ICI in the character code. In the case of the receiver of US Patent No. 10 / 289,749, the same hardware structure can be used to implement the FMIC deviation calculation device 36a in Mode 1 and the CCK correlator module 36b in Mode 2. In other words, the same hardware structure can be used, shared 〃 ′, or used at two different occasions ’and will have two different functions. During mode 2 operation, the channel matching filter CMF 28 uses the channel matching filter CMF label weight provided by the channel pulse judging device 24 to combine the energy of the received signals through the multi-path channels. In Fig. 2, the output of the channel matched filter 28 is designated Rk. For the k-th CCK character code, 'Each Rk contains eight received bits l> 8k, r8k + i, r8k + 2, r8k + 3, r8k + 4, r8k + 5, r8k + 6, r8k +7]. A detailed description of formulating Rk in a multipath channel is shown in FIG. 5 '. There will be a detailed related description in FIG. 5 below. 13 1297otwf.doc / 006 In detail, a CCK character code contains 8 CCK bits, which is the 802.lib standard developed by the IEEE in 1999. In the following, C = = 〇, 1, ···, 255} is used as the mark of the CCK codebook (Codebook) and will be used to mark the mth CCK character code in the CCK codebook. The k-th transmitted CCK character code is denoted as ck:
Ck0? Ckl? Ck25 Ck3, 0^4, Ck55 Ck6, Ck7?], 在此，每一個CCK位元cki爲{ΐ，γ/2，πΆ/2}(或者是 {，，，/4产4严4})中的一個四相位鍵移（Quadra-Phase Shift Keying，以下簡稱QPSK)複數數目，其中第一個指 標k係表示爲傳輸的時間順序，而第二個指標i係表示在 CCK字元碼中之第i個CCK位元。而Ck係CCK編碼本 中己的其中一個。當一個802.11b的傳輸器工作在11Mbps 模式時，會將8個資料位元組合一起以決定傳送的CCK 字元碼，而這8個位元的二進位表示式係用來決定傳輸的 CCK字元碼之指標値。例如8個資料位元爲10000001(129 的二進位表示式），則會被編碼爲ςΐ29來傳輸。而802.11b 接收器的目的，就是將此8個資料位元正確地加以解碼。 CCK關聯器模組36b係將接收位元Rk (—次8個位元) 進行FWT，以計算8個接收位元與256個CCK字元碼其 中的64個CCK字元碼之間的關聯性。這64個輸出只要 簡單地延伸，就可以獲得所有256個CCK字元碼之間的 關聯性，其在以下的第（2)方程式中被標示爲 <〇 = 0，1，...，255)(也如圖2所示）。本發明中之CCK關聯器 模組36b的架構，同樣也可以與美國專利序號第10/289,749 號所繪示之不同的CCK關聯器模組36b相同。 14 f.doc/006 本發明之圖2所繪示之FMIC偏差計算裝置36a和CCK 關聯器模組36b係分開的構件。在一般的實施例中，36a 和36b這兩個裝置實際上可以分成兩個構件，或者也可以 共享同一個硬體結構（如美國專利序號第10/289,749所繪 示）。 最後’連接字符碼解碼器25係擷取 <匕^ = ()，1，...，255)和 預先計算之FMIC偏差當作輸入，並且使用程序#1和#2(以 下所敘述)對CCK字符碼共同地解碼。而解碼資料係連接 字符碼解碼器25的輸出，並且表現在802.11b接收器的輸 出上。 在提供連接字符碼解碼器25完整的描輸之前，以下 先要以一個數學模型來描述多路徑通道。這將會看到一個 字符碼解碼器是對此類傳播通道最適合的解碼器。 多路徑傳播時常伴隨著訊號反射在牆壁、家倶、人類 身上、和其他物件，而出現在成對的無線區域網路裝置之 間，例如傳輸器和接收器。在一個802.11b接收器中，CCK 訊號在經過多路徑傳播時，會導致接收因爲傳輸訊號隨著 不同時間的延遲和強度，所造成的多重複製（Multiple Copies)。若是沒有適當地降低這些、反射波(Echoes)〃，就 會慢慢地造成接收器的表現下降，以及導致產生無法接受 的品質和/或使得傳輸範圍衰減。 爲了加強在多路徑傳輸環境中的訊雜比（Signal-t0-Noise Ratio)，通常會使用例如裝置28的通道匹配濾波器 CMF。它也與RAKE接收器一樣普遍地被熟知。通道匹配 濾波器CMF 28的運作，係配合來自於通道脈衝響應判斷 15 1244275 12976twf.doc/006 裝置24之最佳的通道匹配濾波器CMF之標籤權値。通道 匹配濾波器CMF 28所輸出之已判斷混合通道脈衝響應， 係將通道脈衝響應裝置24所產生之已判斷通道脈衝響應， 以及通道匹配濾波器CMF 28之標籤權値取其旋積。在通 道匹配濾波器CMF 28的輸出中，多路徑合倂增益 (Multipath Combining Gain) hemf 係依據 Proakis 來得知。 從圖3中可以看到一個典型的無線區域網路多路徑強度曲 線，其是複製於偉伯斯徹的圖9。這條曲線有較短的前游 標部分和較長的後游標部分。在RAKE(CMF)以後（包含 RAKE)，一個典型的已判斷混合通道脈衝響應會具有大約 同樣長度的前游標部分和後游標部分。如圖4所顯示，不 同的前游標和後游標路徑之複數增益値被分別對應標示爲 Fi和&，其中i係用來指示在CCK位元中的相關路徑延 遲。目標訊號係存在於混合通道脈衝響應的中央，並且接 收一個由RAKE產生的處理增益hemf。 如本發明的圖5中所揭露的，其顯示處理多路徑的問 題。在所給的字符碼中，有三種多路徑干擾形式：⑴由前 一字符碼所產生之字符碼間干擾ISI，（ii)由目前字符碼所 產生之字符碼內位元干擾ICI，以及（⑴)由下一字符碼所產 生之字符碼間干擾ISI。在典型的802.11b無線區域網路 中，一個傳輸器和一個接收器的距離，大約在數百呎（feet) 之內。一個典型的傳輸器係經由天線傳送其訊號。訊號在 到達目標接收器之前，會在多路徑傳播的環境中行進。在 所有的接收路徑中（不太可能只有一條路徑），會具有許多 的反射，這些反射在超過700呎的傳輸距離下’仍然強大 16 2〇75twf.doc/006 到能夠被偵測。一個CCK字符碼大約727ns長，我們可 以安全地假設，多路徑干擾只來自於目前CCK字符碼和 相鄰的兩個CCK字符碼。圖5係繪示了所有的多路徑干 擾成分。 在圖5中，假設有三個CCK字符碼爲#〇(前一字符碼）， #1(目前字符碼）和#2(下一字符碼），其分別經由多路徑環 境被順序的傳送出去，並且被CCK接收器20所接收。在 圖5中所顯示之每一列（Row)表示一個特定的路徑，並且 所顯示的每一行（Column)係一個特定的時間情況。C的第 一個下標爲CCK字元碼（字符碼）的數目，而第二個下標係 CCK字元碼中位元的指標。接收位元rk係從通道匹配濾 波器CMF 28的輸出中取樣（Sample)，而rk等於具有來自 於混合通道頻率響應之前游標權値Fi和後游標權値1所 加權的行總和。例如r8爲首的這一行，合倂參照圖4之後 我們可以得到·· r8 ~ ^7C17 + ^6^16 + ^5C\5 + ^4C14 + ^3C13 + ^2CU + ^\C\\ + ^cmfC\0 + 方1〔〇7 + 万2(06 + 万3〔05 + 万4(04 + 万5(03 + 方6仁02 + 万7C01Ck0? Ckl? Ck25 Ck3, 0 ^ 4, Ck55 Ck6, Ck7?], Here, each CCK bit cki is {ΐ, γ / 2, πΆ / 2} (or {,,, / 4 yields 4 A four-phase key shift (Quadra-Phase Shift Keying, hereinafter referred to as QPSK) plural number in strict 4}), where the first index k is expressed in the time sequence of transmission, and the second index i is expressed in the CCK word The i-th CCK bit in the metacode. Ck is one of the CCK codebooks. When an 802.11b transmitter works in 11Mbps mode, 8 data bits are combined to determine the CCK character code to be transmitted. The 8-bit binary expression is used to determine the CCK word to be transmitted. Index of metacodes 値. For example, 8 data bits are 10000001 (binary expression of 129), they will be encoded as ςΐ29 for transmission. The purpose of the 802.11b receiver is to correctly decode these 8 data bits. The CCK correlator module 36b performs FWT on the received bits Rk (8 times bits) to calculate the correlation between the 8 received bits and 64 CCK character codes out of 256 CCK character codes. . As long as these 64 outputs are simply extended, the correlation between all 256 CCK character codes can be obtained, which is labeled as < 〇 = 0, 1, ... in the following equation (2) 255) (also shown in Figure 2). The architecture of the CCK correlator module 36b in the present invention may also be the same as the different CCK correlator module 36b shown in US Patent No. 10 / 289,749. 14 f.doc / 006 The FMIC deviation calculation device 36a and the CCK correlator module 36b shown in FIG. 2 of the present invention are separate components. In a general embodiment, the two devices 36a and 36b may actually be divided into two components, or they may share the same hardware structure (as shown in US Patent No. 10 / 289,749). Finally, the 'connected character code decoder 25 series captures < ^^ = (), 1, ..., 255) and the pre-calculated FMIC deviation as inputs, and uses programs # 1 and # 2 (described below) CCK character codes are decoded collectively. The decoded data is connected to the output of the character code decoder 25 and is displayed on the output of the 802.11b receiver. Before providing a complete description of the connected character code decoder 25, the following describes a multi-path channel with a mathematical model. You will see that a character code decoder is the most suitable decoder for this type of propagation channel. Multipath propagation is often accompanied by signal reflections on walls, furniture, humans, and other objects, and appears between pairs of wireless LAN devices, such as transmitters and receivers. In an 802.11b receiver, when the CCK signal propagates through multiple paths, it will cause the reception of multiple copies (Multiple Copies) due to the delay and strength of the transmitted signal with different time. If these echo waves are not properly reduced, the receiver's performance will slowly decrease, resulting in unacceptable quality and / or attenuation of the transmission range. In order to enhance the signal-to-noise ratio in a multi-path transmission environment, for example, the channel matched filter CMF of the device 28 is usually used. It is also as well known as RAKE receivers. The operation of the channel matching filter CMF 28 is based on the label weight of the best channel matching filter CMF from the device 24, which is determined from the channel impulse response 15 1244275 12976twf.doc / 006. The judged mixed channel impulse response output by the channel matched filter CMF 28 is the convolved product of the judged channel impulse response generated by the channel impulse response device 24 and the label weight of the channel matched filter CMF 28. In the output of the channel-matched filter CMF 28, the Multipath Combining Gain hemf is obtained according to Proakis. A typical wireless LAN multipath strength curve can be seen in Figure 3, which is reproduced from Figure 9 of Weberscher. This curve has a shorter front cursor portion and a longer rear cursor portion. After RAKE (CMF) (including RAKE), a typical judged mixed channel impulse response will have a front cursor part and a rear cursor part of approximately the same length. As shown in Figure 4, the complex gains 不 of the different forward and backward cursor paths are labeled Fi and & respectively, where i is used to indicate the relative path delay in the CCK bit. The target signal is in the center of the mixed channel impulse response and receives a processing gain heMF generated by RAKE. As disclosed in Figure 5 of the present invention, it shows the problem of dealing with multipath. Among the given character codes, there are three forms of multipath interference: (i) inter-character code interference ISI generated by the previous character code, (ii) inter-character bit interference of ICI generated by the current character code, and ( Ii) Inter-symbol interference ISI generated by the next character code. In a typical 802.11b wireless LAN, the distance between a transmitter and a receiver is within a few hundred feet. A typical transmitter transmits its signal via an antenna. Before the signal reaches the target receiver, it travels in a multipath environment. In all the receiving paths (it is unlikely that there is only one path), there will be many reflections, and these reflections are still strong at a transmission distance of more than 700 feet 16 205twf.doc / 006 to be able to be detected. A CCK character code is approximately 727ns long. We can safely assume that multipath interference only comes from the current CCK character code and two adjacent CCK character codes. Figure 5 shows all the multipath interference components. In FIG. 5, it is assumed that three CCK character codes are # 〇 (previous character code), # 1 (current character code) and # 2 (next character code), which are sequentially transmitted through a multi-path environment, respectively. And received by the CCK receiver 20. Each row (Row) shown in Fig. 5 represents a specific path, and each row (Column) shown is a specific time condition. The first subscript of C is the number of CCK character codes (character codes), and the second subscript is an indicator of the bits in the CCK character codes. The receiving bit rk is sampled from the output of the channel matching filter CMF 28, and rk is equal to the sum of the weighted rows with the previous cursor weight 値 Fi and the back cursor weight 値 1 from the mixed channel frequency response. For example, the line headed by r8, after referring to Figure 4, we can get r8 ~ ^ 7C17 + ^ 6 ^ 16 + ^ 5C \ 5 + ^ 4C14 + ^ 3C13 + ^ 2CU + ^ \ C \\ + ^ cmfC \ 0 + Fang 1 (〇7 + Wan 2 (06 + Wan 3 (05 + Wan 4 (04 + Wan 5 (03 + Fang 6 Ren 02 + Wan 7C01
在通道匹配濾波器CMF 28的輸出，假如我們從CCK 字符碼#1來看每一個接收位元rk，會看到有一個目標訊號 (請看到圖5有一條被命名爲、、目標CCK字符碼〃的路徑）， 以及其他的14個多路徑干擾成分：其分別由前一 CCK字 符碼（字符碼#〇)、目前字符碼(字符碼#1)和下一 CCK字符 碼（字符碼#2)所產生之七個前游標干擾(請看圖5中之前游 標多路徑ISI(字符碼間干擾)和ICI(字符碼內位元干擾)）， 以及七個後游標干擾（請看圖5中之後游標多路徑isi和 ICI) 〇 17 wf.doc/006 1244¾¾ 假設忽略外加的雜訊，則圖5中所表示的所有訊號和 多路徑干擾成分，可以用一個矩陣方程式來描述： R\ 二 BupC0 + HBhFC\ + FhwC2 在此，則分別令接收字符碼R!和三個傳輸字符碼（前一字 符碼C。、目前字符碼C!和下一字符碼C2)爲： A = [ WlO丨，厂12，丨3，14，J7 = [C〇〇 , C〇l , ^02，^03，^04，亡05，^06，^07 ] = [^10^11^12^13^145^155^16^17] = [^20，〔21，〔22，亡23，〔24，（25，（26，（27 ] 述 描 被 擾 干 徑 路 多 之 生 產 所 碼 符 字1 下 和 碼 符 字1 r 由 而 F! 和 P BU 的 下 以 爲 > 1 2 3 4 5 6 7 1F 5β55Ββ5ο 52 53 54 55 56 57 ο ο ^54^5^570 0 0 54 55 56 57 0 0 0 0 55 56 57 0 0 0 0 0 5657000000D^/ooooooo00000000 ___ II 5At the output of the channel matching filter CMF 28, if we look at each receiving bit rk from the CCK character code # 1, we will see a target signal (please see Figure 5 has a named, target CCK character Code path), and 14 other multipath interference components: it consists of the previous CCK character code (character code # 〇), the current character code (character code # 1), and the next CCK character code (character code # 2) Seven previous cursor interferences (see the previous cursor multipath ISI (inter-character code interference) and ICI (character bit interference within the character code) in Figure 5), and seven rear cursor interferences (see Figure 5) After the cursor multipath isi and ICI) 〇17 wf.doc / 006 1244¾¾ Assuming that the added noise is ignored, all the signals and multipath interference components shown in Figure 5 can be described by a matrix equation: R \ two BupC0 + HBhFC \ + FhwC2 Here, the received character code R! And the three transmitted character codes (previous character code C., current character code C !, and next character code C2) are respectively: A = [WlO 丨, Plant 12, 丨 3, 14, J7 = [C〇〇, C〇l, ^ 02, ^ 03, ^ 04, death 05, ^ 06, ^ 0 7] = [^ 10 ^ 11 ^ 12 ^ 13 ^ 145 ^ 155 ^ 16 ^ 17] = [^ 20, [21, [22, Death 23, [24, (25, (26, (27)) The production of disturbed paths has many codewords 1 and code symbol 1 r, so F! And P BU think that > 1 2 3 4 5 6 7 1F 5β55Ββ5ο 52 53 54 55 56 57 ο ο ^ 54 ^ 5 ^ 570 0 0 54 55 56 57 0 0 0 0 55 56 57 0 0 0 0 0 5657000000D ^ / ooooooo00000000 ___ II 5
FIFI
oooooooo OOOOOOOR^ 000000^7^6 00000^7^6^5 ο ο ο o F7 F6 F5 F4 ο ο ο f7 f6 f5 f4 f3 ο ο f5 f3 f2 o F7 f5 f3 FI 在其間，接收訊號也包括字符碼內位元干擾ICI(例如 因爲多路徑傳播所產生之目前CCK字符碼#1的多重影 1244275 12976twf.doc/006 像）。因此以下以一個矩陣，來描述所有CCK字符碼之多 FI ^ F6 F3 ^ 51 F5 F2 FI 52 F4 ^ 51 52 53 F3 FI 51 52 53 54 12rlW/>1 2 3 4 5FFrl 2 3 4 5 6 Ft5555«« 1 2 3 4 5 6 7 t5cq55cqcqcq • · I-II響廳影//徑路 =Blow + Kmf1 + Fup 在此，由目前字符碼之後游標和前游標所產生之多路徑干 擾 F ο和。 W ο Β,ο 的ο下 ), I 1 2 3 4 5 6 7以rocqoqlJgOQOQlBcq· 係¾ oo 051^53 o o5152^3Qcr ο 51 52 53 54 55 丨 1 2 3 4 5 6 QqQqcqoqcq5 述； 描 oooooooo 來 ^j ooooooo 矩 0000005,1^2oooooooo OOOOOOOR ^ 000000 ^ 7 ^ 6 00000 ^ 7 ^ 6 ^ 5 ο ο ο o F7 F6 F5 F4 ο ο ο f7 f6 f5 f4 f3 ο ο f5 f3 f2 o F7 f5 f3 FI In the meantime, the received signal also includes the character code Internal bits interfere with ICI (for example, multi-images of the current CCK character code # 1 due to multipath propagation 1244275 12976twf.doc / 006 image). Therefore, the following describes the number of CCK character codes in a matrix FI ^ F6 F3 ^ 51 F5 F2 FI 52 F4 ^ 51 52 53 F3 FI 51 52 53 54 12rlW / > 1 2 3 4 5FFrl 2 3 4 5 6 Ft5555 «« 1 2 3 4 5 6 7 t5cq55cqcqcq • · I-II Auditorium // Path = Blow + Kmf1 + Fup Here, the multi-path interference F ο caused by the cursor after the current character code and the cursor before it. W ο Β, ο under ο), I 1 2 3 4 5 6 7 is based on rocqoqlJgOQOQlBcq · ¾ oo 051 ^ 53 o o5152 ^ 3Qcr ο 51 52 53 54 55 丨 1 2 3 4 5 6 QqQqcqoqcq5 description; description oooooooo ^ j ooooooo moment0000005,1 ^ 2
F7 f6 f5 f4 f3 f2 FI o F6 f5 f4 f3 f2 FI o o f5 f4 f3 f2 FI ο ο o F4 F3 FI ο ο ο o ^3^θοοοοο ^2ti7000000 ^Mooooooo oooooooo 以及在R內的目標訊號係具有一個時數的通道匹配濾波器 增益hemf，其可以用一個8乘8的單位矩陣來加以描述。 一般來說，接收訊號Rk係被用於對目前字符碼匕來 角军碼，其可以被描述爲： 1244275 12976twf.doc/006F7 f6 f5 f4 f3 f2 FI o F6 f5 f4 f3 f2 FI oo f5 f4 f3 f2 FI ο ο o F4 F3 FI ο ο ο o ^ 3 ^ θοοοοο ^ 2ti7000000 ^ Mooooooo oooooooo and the target signal system in R has one The number of channel matched filter gains heMF can be described by an 8 by 8 identity matrix. Generally speaking, the received signal Rk is used to send the military code to the current character code, which can be described as: 1244275 12976twf.doc / 006
Rk = [ru，rU + l，r8k + 2，r8k+3，rU+4，r8k+5，，％+7 j 二 KPCk_' + HBhFCk + F-Ck+' = BupCk—，BhwCkRk = [ru, rU + l, r8k + 2, r8k + 3, rU + 4, r8k + 5 ,,% + 7 j Two KPCk_ '+ HBhFCk + F-Ck +' = BupCk—, BhwCk
在實際的接收器運作中，通道脈衝響應判斷裝置24係爲 了多路徑強度曲線而提供判斷，其中多路徑強度曲線可以 描述爲(B up? ^BhF? F1 〇w)或疋（BUp’ B|GW, hemf, FUp，FJ()w)。以下’ 瓦尸，4咖，也/^成<，4和户—被用來分別表不11)，6丨(^，11(^5?1]1)以 及F1()w的估計値。 請參照圖5中被命名爲目前字符碼的數行，從其中可 以辨識出四個多路徑干擾成分。每一個多路徑干擾的成 分，都形成一個類似三角形的形狀（用虛線圍起來的區域）。 其中，有第一三角形(見範圍內所有的CCK字符碼C的第 一個下標都是0)係用來表示由目前字符碼所產生之字符碼 間干擾ISI，第二和第三三角形(見範圍內所有的CCK字 符碼C的第一個下標都是1)係用來表示由目前字符碼所產 生之字符內位元干擾ICI，以及第四三角形（見範圍內所有 的CCK字符碼C的第一個下標都是2)係用來表示由下一 字符碼所產生之字符碼間干擾ISI。 總結來說，上述完整的數學模型，係用來描述在典型 的無線區域網路中多路徑傳播通道相遇的情形。因此我們 可以觀察到，當一個CCK字符碼進行解碼時，一個最佳 的CCK子付碼解碼益’需要考慮到所有因爲cCK字符碼 本身以及兩個相鄰CCK字符碼所造成的多路徑干擾。 此外，本發明提供一種低複雜度且近似完美之連接字 符碼解碼器，係使用連續接收字符碼中的資料，以共同地 對每一個CCK字符碼解碼。在本發明之圖2中的接收器 2〇 ’具有CCK關聯器模組36b，係將一個RAKE接收器 20 1244275 12976twf.doc/006 或是通道匹配濾波器CMF 28的輸出（在第（1)方程式和圖2 中的Rk)當作輸入，並且獲得接收訊號Rk和所有可能的 (Potential) CCK 字元碼〔w(m = 0，l，..”255): R"Cm = (BupCk., -f Bl0WCk -f hcmjCk -f FupCk + FlowCM)hcm Eq.(2) 在此，{}H被記作hermitian方程式（也就是所謂的、複數 轉置（Complex Transpose)"方程式）。連接字符碼解器25 係將多路徑干擾所摻雜之關聯輸出#已0 = ，255)、通道 脈衝響應判斷裝置24所計算出之前饋FF和後饋FB標籤 權値、以及FMIC偏差計算裝置36a之前計算FMIC偏差 値(在模式1期間取得）當作輸入，並且進行連接字符碼多 路徑干擾抵消，以獲得近似完美的解碼效果。 更完全地來認識本發明，首先必須指出，實現一個連 接字符碼解碼器之最主要的挑戰，係在於其本身的複雜 度。在對第k個傳輸CCK字元碼Ck解碼時，在每一個256 個關聯輸出中，目標位元係以下式來表示： {Kmfckfcm 對正確之CCK字元符號（當而言，目標訊號爲一個 實數。而我們可以觀察到，第（2)方程式是一個實際地複數 運算。當接收器運作時，爲了節省硬體的架構，在第（2)方 程式中所有的目標訊號和多路徑干擾的項目，我們可以忽 略其虛數（laginary)的部分，而只要對其實數部分加以運 算。在以下，當我們爲了節省硬體的架構，而只要計算目 標訊號或是多路徑干擾之項目的實數部分時，並不會特別 地去強調。熟習此技藝者當可以知道，一個簡化的實施例 只考慮實部（Real Part)的運算是合理的。在CCK關聯器模 21 1244275 12976twf.doc/006 組36b的輸出，其多路徑干擾失真係表示爲： (a) 由前一字元碼所產生之字符碼間干擾ISI : 心—h (b) 由目前字元碼Ck所產生之字符碼內位元干擾ICI: (b^c^f^c.Yc^ (c) 由下一字元碼（^+1所產生之字符碼間干擾ISI: {^low^k+\ ) 對上述（a)中起因於目前CCK字符碼之多路徑失真而 言’我們可以用&和來判斷起因於依據每一可能的目 前字元碼^之多路徑失真。若是&非常靠近％，並且過 去字符碼被正確的解碼(例如6^=0^)，我們就可以扣除來 自於第m個CCK相關器輸出之，以有效地抵消 此多路徑失真。 爲了表示上述(b)中起因於目前字符碼(ICI)的多路徑失 真’我們可以用下列的式子來判斷字符碼內位元干擾ICI 偏差： icim=dPjgmIn the actual operation of the receiver, the channel impulse response judging device 24 provides judgment for the multi-path intensity curve, where the multi-path intensity curve can be described as (B up? ^ BhF? F1 〇w) or 疋 (BUp 'B | GW, hemf, FUp, FJ () w). The following 'tile corpse, 4 coffee, also / ^ 成 <, 4 and households — are used to express the estimates of 11), 6 丨 (^, 11 (^ 5? 1) 1) and F1 () w Please refer to the lines named as the current character code in Figure 5, from which four multipath interference components can be identified. Each multipath interference component forms a triangle-like shape (the area surrounded by the dotted line) ). Among them, the first triangle (see the first subscript of all CCK character codes C in the range is 0) is used to indicate the inter-character interference ISI generated by the current character code, the second and third The triangle (see the first subscript of all CCK character codes in the range is 1) is used to indicate that the intra-character bit interference ICI generated by the current character code, and the fourth triangle (see all CCK in the range) The first subscript of character code C is 2), which is used to represent the inter-character interference ISI generated by the next character code. In summary, the above complete mathematical model is used to describe the typical wireless area The situation where multipath propagation channels meet in the network. So we can observe that when a CCK When decoding a symbol, an optimal CCK subcode decoding benefit needs to consider all multipath interference caused by the cCK character code itself and two adjacent CCK character codes. In addition, the present invention provides a low complexity And the near-perfect connection character code decoder uses the data received in the character code to continuously decode each CCK character code. The receiver 20 ′ in FIG. 2 of the present invention has a CCK correlator module. 36b, taking the output of a RAKE receiver 20 1244275 12976twf.doc / 006 or the channel matched filter CMF 28 (in equation (1) and Rk in Fig. 2) as input, and obtaining the received signal Rk and all Possible (Potential) CCK character code [w (m = 0, l, .. "255): R " Cm = (BupCk., -F Bl0WCk -f hcmjCk -f FupCk + FlowCM) hcm Eq. (2) Here, {} H is referred to as the Hermitian equation (also known as the Complex Transpose " equation). The connection character code resolver 25 is a correlated output doped with multipath interference # 已 0 = , 255), calculated by the channel impulse response judging device 24 FF and feed-back FB tag weights 値, and FMIC deviation calculation means 36a calculates FMIC deviation 之前 (obtained during mode 1) as input, and performs multi-path interference cancellation of connected character codes to obtain an approximately perfect decoding effect. To fully understand the present invention, we must first point out that the most important challenge in implementing a connected character code decoder lies in its complexity. When decoding the k-th transmission CCK character code Ck, in each of the 256 associated outputs, the target bit is represented by the following formula: {Kmfckfcm For the correct CCK character symbol (when the target signal is a Real numbers. And we can observe that equation (2) is a practical complex number operation. In order to save the hardware architecture when the receiver is operating, all the target signal and multipath interference items in equation (2) , We can ignore its imaginary part, and only need to calculate the real part. In the following, when we want to save the hardware structure, we only need to calculate the real part of the target signal or multipath interference project, It will not be particularly emphasized. Those skilled in this art will know that it is reasonable to consider only the real part operation in a simplified embodiment. In the CCK correlator module 21 1244275 12976twf.doc / 006 Group 36b The output, the multipath interference distortion is expressed as: (a) Inter-character code interference ISI generated by the previous character code: Heart—h (b) Inner character code generated by the current character code Ck Element interference ICI: (b ^ c ^ f ^ c.Yc ^ (c) Inter-character code interference caused by the next character code (^ + 1) ISI: {^ low ^ k + \) For the above (a) Due to the multi-path distortion of the current CCK character code, we can use & sum to determine the multi-path distortion due to each possible current character code ^. If & is very close to%, and the past character code is Correct decoding (for example, 6 ^ = 0 ^), we can subtract the output from the m-th CCK correlator to effectively offset this multipath distortion. In order to indicate that (b) above is caused by the current character code (ICI Multipath distortion 'we can use the following formula to determine the bit interference ICI deviation in the character code: icim = dPjgm
其中m=0，l，2,…，255，在此係用m將每一個256個CCK 字元碼候選者編號。我們可以觀察到，當（b)中所示之字符 碼內位元干擾ICI偏差具有一個G和一個已，上述(b)中所 示之字符碼內位元干擾ICI偏差，係不等於上述之已判斷 字符碼內位元干擾ICI偏差，而已判斷字符碼內位元干擾 ICI偏差則具有兩個已。注意一點，G還沒有被解碼。上 述之已判斷字符碼內位元干擾ICI偏差都很相近，係因爲 目則CCK字符碼（*)可以只疋256個CCK字元碼（^)中 22 1244275 12976twf.doc/006 的一個。因此，已判斷字符碼內位元干擾ICI偏差只有對 正確之目前CCK字符碼才是正確的。依據每一其他的255 個CCK字符碼，當已判斷字符碼內位元干擾ICI偏差被 依附在相對應之CCK關聯器模組36b的關聯輸出時’失 真會更加的嚴重。因此當我們需要接收器的架構保持簡單 時，只能夠降低這種多路徑失真。爲了提供最好的降低效 果，在以下我們提供了一個輕偏差（Soft Bias): a-ICIm=a^CHm(Bl0W^Fupfcm 其中η。而最佳的α値可以由電腦模擬來尋得。 基於同樣的原因，上述(c)中起因於下一 CCK字符碼 (G+1)的多路徑失真也能被降低。以下我們可以提供一個輕 偏差來降低起因於下一 CCK字符碼（Q+1)之多路徑干擾： 其中。而最佳的沒値可以由電腦模擬來尋得。 總合來說，當對第k個傳輸CCK字元碼G解碼時·· 1) 多路徑干擾失真（a)可以用回饋FB標籤和前一字元碼Cm 的估計値來移除。 2) 多路徑干擾失真(b)可以用回饋FB和前饋FF標籤的估 計値來降低。 3) 多路徑干擾失真（c)可以用前饋FF標籤和下一字兀碼 的估計値來降低。 爲了讓系統有最好的表現，理論上我們要降低在圖5 中四個三角形所表示的所有多路徑干擾失真。這需要回饋 FB和前饋FF標籤的估計値，以及前一字元碼和下一字元 23 1244275 12976twf.doc/006 碼的估計値。一般來說，當考慮一個字元碼q的解碼時， 我們可以假設前一字元碼Cp已經被解碼，並且我們需要 用於下一字元碼的估計値。因此最理想的情況，第k 個字元碼係依據256個關聯器輸出（<已）、多路徑通道描 述（H之，am之^)、解碼的解碼的前一字元碼（U和下〜 接收字元碼的估計値來進行解碼。爲了作一個決定來顧慮 到目前CCK字元碼，在此需要注意，一個CCK字元碼延 遲係需要取得下一字元碼的估計値。 因爲有256個CCK字元碼候選者，我們可以想像， 在目前CCK字元碼Q進行最後解碼之前，一個連接字符 碼解碼器，係需要個目前字元碼和下一字元碼所有 65536(4562)個組合的可能性估計値。這個巨大數字，係 使得在設計此種連接解碼器上變得不切實際。因此我們的 目的，在於設計一個低複雜度的連接解碼器，其可以不用 去計算所有65536個字元碼而能有效地降低所有的多路徑 干擾失真。 以下描述一個近似完美之低複雜度連接字符碼解碼器 25。此連接字符碼解碼器25的要點，在於進行連接解碼 之前，找出用於目前字元碼G的沁個起始估計値係遠 小於256)，以及用於下一字元碼^^的沁㈠個起始估計値 (从㈢係遠小於256)。因此，當爲了決定字元碼G時，只有 個組合需要用於連接字符碼解碼器25的運算。這種 減少組合的數目係爲了可以簡單地將接收益20貫現而考 慮，並且在移除或是降低所有的多路徑干擾失真（例如四 個三角形)都有極佳的表現。 24 1244¾為 6twf.doc/006 連接字符碼解碼器25包括了帛成以下所欽述之程序#1 和#2的硬體，以按照順序共同地和有效地對多路徑干擾所 在之傳輸CCK #符碼解碼。熟習此?支藝者可以輕易地依 據以下程序#1和#2的描述，來實現連接字符碼解碼器。 以下程序#ι的描述，係指出對目前CCK字元碼〇和下一 CCK字元碼Q+1來取得起始估計値， 捏违_虹：對第k個傳輸CCK字元碼q和第k+1個傳輸 cck子兀碼Cw來取得起始估計値： 需要的輸入： (及)(^艮關聯益模組361)的輸入：<〇 = 〇，1，2，...，255)和7?爻1£/„。 (b)FMIC偏差計算裝置36a的輸入： FMIC偏差計算裝置36a (可以與美國專利序號第 10/289,749號的方塊36a相同）係用來有效地預先計算這些 多路徑干擾輸出，爲了使每一個CCK字元碼(用m來標示) 具有由電腦模擬之最佳的α。α是一個介於〇至1的數字。 這些多路徑輸出係用來表示起因於目前CCK字元碼之已 判斷字元碼內位元干擾ICI偏差。在每一個封包的序言期 間，多路徑干擾輸出只會被計算計算一次，並且將之儲存 來用於所有的256個字元碼。 步驟1 :依據CCK關聯器模組36b之關聯器輸出 ， 係使用FMIC偏差計算裝置36a之預先計算的字符碼內位 元干擾ICI偏差，以獲得ICI校正關聯輸出(ICI-Corrected correlation Outputs)以當作第k個（例如目前的）傳輸字元碼 (或是字符碼）。更詳細地說，依據每一個256個關聯器輸 25 :wf.doc/006 出（以m來標記），扣除來自於CCK關聯輸出<已之相對 應的多路徑干擾，以獲得ICI校正關聯輸出來當作第 k個傳輸字元碼。爲了執行此步驟，可能會使用CCK字元 碼和多路徑干擾偏差的對稱特性以將偏差的數目降低，係 由256減至32或是16，就如美國專利序號第1〇/289,749 號所述，並且仍然可以達到同等級的表現。 步驟2 :從由步驟1所取得之256個校ICI校正關聯 輸出中間，選擇Mk個CCK字元碼，其ICI校正關聯輸出 係最大的Mk値。這些吣個CCK字元碼係用於目前CCK 字元碼Ck的起始估計値，其被標示爲Q，,(i=l，2，.··，Mk)。以 下爲求方便描述，則令4來表示對應於Q,,.(i=l，2，...，Mk)的 ICI校正關聯輸出。 賴」一:在一個延遲之後，當關聯器輸出把對於下 一(第k+1) CCK字元碼或是字符碼變成有用的時候，則重 複上述之步驟1，以獲得用於第k+Ι個傳輸字符碼的ICI 校正關聯輸出，並且重複上述之步驟2，以獲得用於下一 CCK字元碼Ck+1的Mk+1個起始估計値，係被標示爲 t，7(j = l，2，···，Mk+1)。以下爲求方便描述，則令^來表示 對應於q+1J(j = l，2，···，Mk+1)的ICI校正關聯輸出。 ^^#1結束 補充上述之步驟1，起因於CCK字符碼本身的多路徑失真 (例如字符碼內位元干擾ICI)，係已經由關聯輸出來降低。 這就是爲什麼我們可以有效地在步驟2中來決定Mk或是 Mk+i個起始估計値。 隨著程序#1中用於目前和下一 CCK字符碼所取得之 26 1244¾ f.doc/006 起始估計値，我們準備使用程序#2來實現連接字符碼解碼 器。令A-i標不爲解碼的CCK字元碼ck_!。依據每一個用 於目前CCK字符碼之Mk個起始估計値，係有M⑴個用於 下一 CCK字符碼之起始估計値。我們需要去判斷這些Mk Mk+1個候選者並且決定目前CCK字符碼。 UJfll :爲了第k個傳輸CCK字元碼ck進行連接字符 碼解碼： 需耍的輸入·· (a) 從程序#1產生之輸入： (al)用於目前CCK字元碼匕(卜1，2，...，]^)之队個 起始估計値，以及其對應之ICI校正關聯輸出仏。 (a2)用於下一 CCK 字元碼(^+1，7G = 1，2，...，Mk+1)之 Mk+1個起始估計値，以及其對應之ICI校正關聯輸出A+u.。 (b) 從通道脈衝響應判斷裝置24所產生之輸入：t和 t(或是相等地 Fj 和 Bj，ί=1，2，···，7) 步驟1 •爲了降低起因於下一' CCK字符碼之多路徑干擾 (字符碼間干擾ISI)的衝擊 (la)對每一個Mk個起始估計値之,(1=1,2,...，Mk)，依據 以下的公式來計算起因於下一字符碼之多路徑干擾， 以用於每一個％+1個起始估計値之〜(」=1，2，...，1^+1)。在 此，β是一個介於1和0之間的數字，其最佳値係由電腦 模擬而決定。 (1 b)依據每一個從步驟（1 a)獲得的結果設置一個最小 値。更詳細地說，依據i=l，2，···，Mk個起始估計値，固定 27 :wf.doc/006 指標i並且讓指標j由1變化到Mk+1，然後找出指標jm,n 以用於每一個i，如 β * FlCkj = {β - C^+]J} (lc)現在，對每一個具有固定之指標i的Mk個起始 估計値，從對應之第i個（直到Mk) ICI校正關聯輸出從 程序#1中取得）扣除 以取得新的一組Mk個關聯輸出认，,（i=l，2，...，Mk):Where m = 0, 1, 2, ..., 255, where each 256 CCK character code candidate is numbered by m. We can observe that when the bit interference ICI deviation in the character code shown in (b) has one G and one, the bit interference ICI deviation in the character code shown in (b) above is not equal to the above. It has been judged that the bit interference within the character code interferes with the ICI deviation, and it has been judged that the bit interference within the character code has an ICI deviation of two. Note that G has not been decoded yet. It is judged that the bit interference ICI deviations in the above-mentioned character codes are very similar, because the CCK character code (*) can only be one of 256 CCK character codes (^), 22 1244275 12976twf.doc / 006. Therefore, it has been judged that the bit interference ICI deviation in the character code is correct only for the correct current CCK character code. According to each of the other 255 CCK character codes, when it is determined that the bit interference ICI deviation in the character code is attached to the correlation output of the corresponding CCK correlator module 36b, the distortion will be more serious. So when we need to keep the receiver's architecture simple, we can only reduce this multipath distortion. In order to provide the best reduction effect, we provide a Soft Bias in the following: a-ICIm = a ^ CHm (Bl0W ^ Fupfcm where η. And the best α 値 can be found by computer simulation. Based on For the same reason, the multipath distortion caused by the next CCK character code (G + 1) in (c) above can also be reduced. Below we can provide a slight deviation to reduce the cause of the next CCK character code (Q + 1) ) Multipath interference: Among them, and the best can be found by computer simulation. In summary, when decoding the kth transmission CCK character code G ... 1) Multipath interference distortion (a ) Can be removed by using the feedback FB tag and the estimate 値 of the previous character code Cm. 2) Multipath interference distortion (b) can be reduced by using the estimate 値 of the feedback FB and feedforward FF tags. 3) Multipath interference distortion (c) can be reduced by using the feedforward FF tag and the estimated 値 of the next word code. In order to get the best performance from the system, we theoretically reduce all the multipath interference distortions represented by the four triangles in Figure 5. This requires feedback estimates of FB and feedforward FF tags, as well as estimates of the previous character code and the next character 23 1244275 12976twf.doc / 006 code. In general, when considering the decoding of one character code q, we can assume that the previous character code Cp has already been decoded, and we need to estimate 値 for the next character code. Therefore, in the most ideal case, the k-th character code is based on the output of the 256 correlators (< already), the multipath channel description (H of, am of ^), the decoded and decoded previous character code (U and The next step is to receive an estimate of the character code for decoding. In order to make a decision to take into account the current CCK character code, it should be noted here that a CCK character code delay requires an estimate of the next character code. Because There are 256 CCK character code candidates. We can imagine that before the current CCK character code Q is finally decoded, a connected character code decoder requires a current character code and the next character code. All of the 65536 (4562 It is estimated that the probability of the combination is 値. This huge number makes it impractical to design such a connection decoder. Therefore, our goal is to design a low-complexity connection decoder, which can be calculated without All 65536 character codes can effectively reduce all multipath interference distortions. The following describes an approximately perfect low complexity connection character code decoder 25. The main point of this connection character code decoder 25 is that Before line-connected decoding, find the starting estimates for the current character code G (which is much less than 256) and the starting estimates for the next character code ^^ (from the system Less than 256). Therefore, when determining the character code G, only a combination is required for the operation for connecting the character code decoder 25. This reduction in the number of combinations is considered in order to make it easy to achieve a good reception, and it has excellent performance in removing or reducing all multipath interference distortion (such as four triangles). 24 1244¾ for 6twf.doc / 006 The connection character code decoder 25 includes hardware that generates the procedures # 1 and # 2 described below to collectively and effectively transmit CCK in sequence to the multipath interference location # Symbol decoding. Familiar with this? The artist can easily implement the connection character code decoder according to the description of the following procedures # 1 and # 2. The description of the following procedure # ι is to point out that the current CCK character code 0 and the next CCK character code Q + 1 are used to obtain the starting estimate 値, which violates _ Hong: For the k-th transmitted CCK character code q and the first k + 1 transmitted cck sub-codes Cw to obtain initial estimates 値: required inputs: (and) (^ gen associated benefit module 361) inputs: < 〇 = 〇, 1,2, ..., 255) and 7? 1 £ / „. (B) Input of FMIC deviation calculation device 36a: FMIC deviation calculation device 36a (may be the same as box 36a of US Patent No. 10 / 289,749) is used to effectively pre-calculate These multipath interference outputs are designed so that each CCK character code (indicated by m) has the best alpha simulated by a computer. Alpha is a number between 0 and 1. These multipath outputs are used to indicate the cause At the current judged character code of the CCK character code, the bit interference ICI deviation. During the preamble of each packet, the multipath interference output will only be calculated once and stored for all 256 words. Meta code Step 1: According to the correlator output of the CCK correlator module 36b, it is a prediction using the FMIC deviation calculation device 36a. The calculated bits in the character code interfere with the ICI deviation to obtain ICI-Corrected correlation Outputs as the k-th (eg, current) transmission character code (or character code). In more detail According to each 256 correlators, input 25: wf.doc / 006 output (labeled as m), subtract the corresponding multipath interference from the CCK correlation output < to obtain the ICI corrected correlation output as The kth transmission character code. In order to perform this step, the symmetrical characteristics of the CCK character code and the multipath interference deviation may be used to reduce the number of deviations from 256 to 32 or 16, as in the US patent No. 10 / 289,749, and can still achieve the same level of performance. Step 2: From the 256 calibration ICI correction correlation outputs obtained in step 1, select Mk CCK character codes, whose ICI correction correlation output Is the largest Mk 値. These CCK character codes are used for the current starting estimate of the CCK character code Ck, which is labeled as Q ,, (i = 1, 2,..., Mk). Below For the convenience of description, let 4 represent Q ,,. (I = l, 2, ... , Mk) ICI correction correlation output. Lai "One: After a delay, when the correlator output becomes useful for the next (k + 1) CCK character code or character code, repeat the above steps 1, to obtain the ICI corrected correlation output for the k + 1th transmitted character code, and repeat step 2 above to obtain Mk + 1 starting estimates 用于 for the next CCK character code Ck + 1, The system is labeled t, 7 (j = 1, 2, ..., Mk + 1). For the convenience of description below, let ^ denote the ICI correction output corresponding to q + 1J (j = 1, 2, ···, Mk + 1). ^^ # 1 End Complement step 1 mentioned above. The multipath distortion caused by the CCK character code itself (such as bit interference ICI in the character code) has been reduced by the associated output. This is why we can effectively decide Mk or Mk + i starting estimates 步骤 in step 2. With the initial estimate of 26 1244¾ f.doc / 006 obtained in program # 1 for the current and next CCK character codes, we are going to use program # 2 to implement the connection character code decoder. Let A-i not be the decoded CCK character code ck_ !. Based on each of the Mk starting estimates for the current CCK character code, there are M starting estimates for the next CCK character code. We need to judge these Mk Mk + 1 candidates and determine the current CCK character code. UJfll: Decode the connected character code for the k-th transmission of the CCK character code ck: Input required ... (a) Input generated from program # 1: (al) Used for the current CCK character code dagger (Bu 1, 2, ...,] ^) 's starting estimates 队, and their corresponding ICI correction correlation outputs 关联. (a2) Mk + 1 initial estimates 用于 for the next CCK character code (^ + 1, 7G = 1, 2, ..., Mk + 1), and its corresponding ICI correction correlation output A + u .. (b) Inputs from the channel impulse response judging device 24: t and t (or equivalently Fj and Bj, = 1, 2, ..., 7) Step 1 • To reduce the cause of the next 'CCK The impact of multi-path interference (inter-character code interference ISI) of character codes (la) on each Mk starting estimate, (1 = 1,2, ..., Mk), calculate the cause according to the following formula The multi-path interference at the next character code is used for each of the% + 1 initial estimates ~ ("= 1, 2, ..., 1 ^ + 1). Here, β is a number between 1 and 0, and its optimal relationship is determined by computer simulation. (1 b) Set a minimum 値 according to each result obtained from step (1 a). In more detail, according to i = 1, 2, ..., Mk starting estimates 値, fixed 27: wf.doc / 006 index i and let index j change from 1 to Mk + 1, and then find index jm , n for each i, such as β * FlCkj = {β-C ^ +] J} (lc) Now, for each Mk starting estimate 値 with a fixed index i, from the corresponding i-th (Until Mk) ICI corrected correlation output is obtained from program # 1) Subtract to obtain a new set of Mk correlation output recognitions, (i = l, 2, ..., Mk):
Qk，i = P/ο - β ·亡k+\、jmi,i〇w亡kj 這些關聯輸出對字元碼候選者之，,(卜1，2，...，“1^)來說是''最 好〃的關聯輸出，其具有降低由目前和下一字符碼所產生 之多路徑干擾。 步驟2 :爲了移除起因於前一 CCK字符碼之多路徑 干擾（字符碼間干擾ISI) (2a)對每一個Mk個起始估計値，係依據以下的方程 式： Αη γ>ηΑ ^k-l^up^kj 計算起因於在CCK關聯器模組36b之輸出中解碼的解碼 的前一字符碼匕的多路徑干擾。在此，之，,心=1，2，...，^^)爲 對應於Mk個起始估計値的Mk個CCK候選字符碼，係用 於第k個傳輸CCK字元碼Ck。 (2b)從上述步驟（lc)中所獲得之第i個關聯輸出中，扣 除。而爲了以下討論的方便，令Wk>1來標示這些 關聯輸出z 〜- ¾«在此 i = 1，2，…，Mk 28 12442¾ twf.doc/006 這些關聯輸出對字元碼候選者之，,(卜1，2，...，?^)來說是 ''最好〃的關聯輸出，其具有降低由上一和目前字符碼所 產生之多路徑干擾。 步驟3 :連接字符碼解碼 連接字符碼解碼器25選擇&，,_(例如爲最大値）當作解 碼的CCK字元碼Q，係當作第k個傳輸字元碼Ck，其具 有指標imax，對應於上述步驟（2b)中之最大關聯輸出Wk i。 換句話說， ，在此 令Q表示解碼的解碼的第k個CCK字元碼（Q = Q)。而解 碼的資料係L的二進位表示。 程序#2結束 當實現上述程序#1和#2之連接解碼器25時，熟習此 技藝者當不需要完全按照上述步驟來達到同等的解碼結 果。例如我們在進行程序#2中步驟3中的解碼資料決定之 前，可以對所有的指標i (i =1，2,…，Mk)和j(j =l，2，...，Mk+1) 來計算所有MkxMk+1的多路徑干擾校正關聯輸出。 對於第k個字元碼Ck來說，起始估計値的數目係標 示爲Mk。一個連接判斷規則(Joint Decision Rule)，係利用 前一字元碼之解碼字元碼、目前字元碼4,(丨=1，2，...，]^〇 的队個候選者，以及下一字元碼Q+l7(j =l，2，...，Mk+1)之Mk+1 個候選者來對第k個字元碼Ck解碼。換句話說，當對第k 個字元碼Ck解碼時，我們需要計算： (1) Mk個具有解碼的字元碼的關聯，以對由前一字元碼 所產生之多路徑干擾進行補償；以及 29 1244275 I2976twf.doc/0〇6 (2)MkxMk+1個關聯，以表示在M…個可能的下一字元碼中 之不同的多路徑干擾。 因此’複雜度係與Mk+MkxMk+1的數目成比例。 右7E 和/或Mk+1爲非常大的數字，則此種連接字符 碼解碼器則不太可能實現。因此，在降低成本的原則下， 應5亥要取得較小之Mk和Mk+1値。在不失去普遍性下，我 以假設以下所討論的所有字元碼，队的數目爲固定 因爲只有256個CCK字元碼被詳細載明在 8〇2.Ub的說明書中，因此我們可以選擇M=256，但是如 达匕會導致組合的數目過大，而使得此連接字符碼解碼器不 切實際。 _ 医’爲了達到近似完美的解碼表現，在實現連接字 碼器25時最需要關切的，係降低所需暫時的字元 I數目Μ。以下的觀察結論係有效的指示： 胃^1)在大多數實際的環境下，多路徑傳播被限制在土只 接Ζ個1 CCK字符碼(8位元或是727ns的長度）。而一個連 μ 1」斷機制係依據三個接收字符碼（前一字符碼、目前字 付碼和γ ^ $符碼），以提供最佳的系統表現。Qk, i = P / ο-β · kk + \, jmi, i〇w kkj These associated outputs are among the character code candidates, (Bu 1, 2, ..., "1 ^) are '' The best correlation output, which has the effect of reducing the multipath interference caused by the current and next character codes. Step 2: To remove the multipath interference caused by the previous CCK character code (inter-character code interference ISI) (2a) For each Mk starting estimate, 系 is based on the following equation: Αη γ > ηA ^ kl ^ up ^ kj Calculates the decoded previous character code resulting from decoding in the output of the CCK correlator module 36b Multipath interference of dagger. Here,, heart = 1, 2, ..., ^^) are Mk CCK candidate character codes corresponding to Mk starting estimates 値, which are used for the kth transmission CCK Character code Ck. (2b) Subtract from the i-th associated output obtained in step (lc) above. For the convenience of the following discussion, let Wk> 1 mark these associated outputs z ~-¾ «here i = 1, 2, ..., Mk 28 12442¾ twf.doc / 006 These associated outputs are among the character code candidates, ((1,2, ...,? ^)) Associative output with reduced Multipath interference caused by the previous and current character codes. Step 3: Connected character code decoding Connected character code decoder 25 selects & ,, _ (for example, the largest 値) as the decoded CCK character code Q, which Let the k-th transmission character code Ck have an index imax, corresponding to the maximum associated output Wk i in the above step (2b). In other words, let Q denote the decoded and decoded k-th CCK character Code (Q = Q). The decoded data is a binary representation of L. End of program # 2. When the decoder 25 of the above procedures # 1 and # 2 is implemented, those skilled in the art need not follow the above steps completely. Reach the same decoding result. For example, before we make the decoding data decision in step 3 in program # 2, we can perform all the indexes i (i = 1, 2, ..., Mk) and j (j = 1, 2, ...). .., Mk + 1) to calculate all MkxMk + 1 multipath interference correction correlation outputs. For the k-th character code Ck, the number of initial estimates 値 is denoted as Mk. A connection decision rule (Joint Decision Rule), which uses the decoded character code of the previous character code, the current character code 4, (丨 = 1, 2, ... ,] ^ 〇 of the team of candidates, and the next character code Q + l7 (j = 1, 2, ..., Mk + 1) of Mk + 1 candidates to the k-th character code Ck In other words, when decoding the k-th character code Ck, we need to calculate: (1) Mk associations with decoded character codes to interfere with the multipath generated by the previous character code Compensation; and 29 1244275 I2976twf.doc / 0〇6 (2) MkxMk + 1 associations to represent different multipath interferences among M ... possible next character codes. Therefore, the 'complexity is proportional to the number of Mk + MkxMk + 1. The right 7E and / or Mk + 1 are very large numbers, and such a connection character code decoder is unlikely to be realized. Therefore, under the principle of reducing costs, it is necessary to obtain smaller Mk and Mk + 1 値. Without loss of universality, I assume that all the character codes discussed below, the number of teams is fixed because only 256 CCK character codes are detailed in the description of 802.Ub, so we can choose M = 256, but if the number is too large, the number of combinations will be too large, making this connection character code decoder impractical. In order to achieve near-perfect decoding performance, the most important concern when implementing the connection to the coder 25 is to reduce the number of temporary characters I required. The following observations are valid indications: Stomach ^ 1) In most practical environments, multipath propagation is limited to only 1 CCK character code (8 bits or 727ns in length). A continuous μ 1 ”break mechanism is based on three received character codes (previous character code, current character code, and γ ^ $ character code) to provide the best system performance.
尼^2)丨衣照美國專利序號第10/289,749號之發明的FMIC 你：to 胃36a ’係提供一種低成本且可靠的方法來降 低起始估 5#値M的數目。這使得一個近似完美低複雜度 _ 付碼解碼器25合理的被實現。更詳細地說，fmic 偏差計爿士竣^ iei 衣置36a係提供一種低成本和可靠的手段來計算 校正關聯輸出。依據這些iCI校正關聯輸出，我們可 以得制 、」〜個很小的起始估計値數目，來用於一個低複雜度 I244^27^twf.doc/006 連接字符碼解碼器。依據電腦模擬的結果，在M=2或3 時可以達到最佳的解碼表現。此很小的數字只要應用今天 的技術就可以輕易地實現。 雖然上述將焦點放在用於運作在i i Mbps模式之 802.1 1b CCK的連接字符碼解碼器25，其使用256個cCK 字元碼在其編碼本上，但熟習此技藝者可以輕易地用相同 的原理和接收器架構，對運作在5·5 Mbps模式之802.11b cck來進行解碼，這些技巧係實際地使用包括有256個字 元碼的編碼本內的一個16 CCK字元碼子集合。 以下的例子係提供程序#1和#2的圖示。圖6係繪示 程序#1的步驟，並且圖7係繪示係繪示程序#2的步驟。 以下例子所提供的數値僅僅用於圖示的目的，並不是實際 的資料。 在圖6中，有256個CCK字元碼候選者，圖6中的 每一列，係用來表示每一個256個CCK字元碼候選者的 結果。第一行係用來提供每一個CCK字元碼的指標m。 第二行顯示CCK關聯器模組36b的關聯輸出，係用於第k 個CCK字元碼。第三行顯示從FMIC偏差計算裝置36a所 取得之預先計算FMIC偏差。第四行係繪示用於第二和第 三行的輸出之程序#1的步驟1。第五行係繪示程序#1的步 驟2。依據第四行顯示的ICI校正關聯輸出，第五行顯示 用於第k個字元碼之起始的Mk(Mk=3)個候選者（在圖6中 被圏起者）爲已忑254和已。圖6中的最後三行（第六、七和八 行)係繪示程序#1的步驟3，爲了第k+Ι個字元碼，實際 地重複步驟1和2，以決定起始的Mk+1(Mk+1 = 3)個候選者而 31 I244^794wf.doc/006 用於第k+1個字兀碼。在此’用於步驟3的FMIC偏差， 係與之前圖6之第三行所設定的相同。在步驟3的結果， 用於第k+Ι個字元碼之起始的Mk+1(Mk+1=3)個候選者係等 於£。，£253和被圈起者）。在整個例子中應該要注意的是， 每一處顯不在方程式Re{}中的數値，在數學上是正確的。 圖7中第一行係顯示指標Mk。所有其他的各行不是 被用於顯示程序#2的步驟’就是顯示程序#2的子步驟。 詳細地說，第二行顯示程序#2的步驟（la)，其中從用於第 k個子兀碼（以i作爲指標’而i = 1，2,3(=Mk))之三個起始字 元碼候選者（仏，^254和G)之一，我們對每一個用於第k+Ι個 字兀碼(以j作爲指標’而j =l，2,3(=Mk+1))的3個起始的字 元碼候選者（^：。，^253和G)，來計算起因於下一字符碼的多路 徑干擾。第三行係顯示步驟（lb)，此處j係指示在步驟（la) 中對應的最小値’其被選取是用於第k個字元碼的三個起 始候選者之一。以起首的字元候選者^作爲例子，將步驟（la) 中所取得的結果（1·1 ’ 〇·5和-0.2)作比較，並且決定最小値 (-0.2)(圖7中被圏起者）。對每一個用於第k個字元碼的起 始候選者而言，此最小値係起因於下一 CCK字元碼之多 路徑干擾估計値。第四行係顯示步驟（lc)。在步驟（lc)中 起因於下一字元碼(第k+Ι個CCK字元碼）之以判斷多路徑 干擾，係由ici校正關聯輸出pki中扣除以得到Qki，是爲 了每一個用於第k個CCK字元碼的起始候選者。在本實 施例中，Qu =9·2，Qk，产9·4和Qk3=7.9。第五行係顯示程 序#2中的步驟（2a)。隨著第k-Ι個CCK字元碼已經被解碼 (第k-Ι個CCK字兀碼係標不爲Q j，我們可以對每一個 32 1244275 12976twf.doc/006 用於第k個字元碼的起始候選者，計算起因於前一 CCK 字元碼之多路徑干擾，如下所示： γη Α//Λ _rH rh r γη Α//Λ 一 rH r ^k-\Dup^k,2 在本實施例中，它們的數値可以被找到分別爲〇·2，-1和 0.6。第六行係顯示步驟（2b)和3。在步驟（2b)中，對每一 個用於第k個CCK字元碼的起始候選者，係從Qkii減去起 因於前一 CCK字元碼之多路徑干擾以獲得Wk>1。在本實施 例中，Wk>1 =9，Wk,2=10.4 和 Wk，3=7.3。Wk，,係表示具有對 每一個用於第k個CCK字元碼的起始候選者之所有多路 徑干擾校正的關聯輸出。在步驟（3)中，第k個字元碼係解 碼完成。在本實施例中，判斷出所有的多路徑干擾校正中 的Wk2 (圖7中被圈起者）爲最大的關聯輸出，其具有。因 此，解碼字元碼爲Α=Α，2=ς254，並且解碼資料爲11111110 ’ 其爲254的二進位表示。 雖然本發明已以較佳實施例揭露如上，然其並非用以 限定本發明，任何熟習此技藝者，在不脫離本發明之精神 和範圍內，當可作些許之更動與潤飾，因此本發明之保護 範圍當視後附之申請專利範圍所界定者爲準。 【圖式簡單說明】 圖1係繪示一種802.llb封包格式。 圖2係繪示依照本發明之一實施例的接收器示意圖。 圖3係繪示依照一個多路徑傳播通道之習知的多路徑 強度示意圖（也就是通道脈衝響應圖）。 33 1244275 12976twf.doc/006 圖4係繪示在RAKE之後的混合通道脈衝響應（CIR) 圖。 圖5係繪示在RAKE之後的接收訊號中所有多路徑成 分示意圖。 圖6和圖7係繪示依照本發明之一實施例之以目前 CCK字符碼來降低多路徑干擾遭遇的方法流程圖。 【圖式標示說明】 22 :選擇器 24 :通道脈衝響應判斷裝置 25 :連接字符碼解碼器 28 :通道匹配濾波器 36a : FMIC偏差計算裝置 36b : CCK關聯器模組 34^ 2) 丨 FMIC according to the invention of US Patent No. 10 / 289,749 You: to stomach 36a ′ provides a low-cost and reliable method to reduce the number of initial estimates 5 # 値 M. This makes a near perfect low complexity _ subcode decoder 25 reasonable to implement. In more detail, the fmic deviation meter can be used to calculate the correlation output. Based on these iCI corrected correlation outputs, we can obtain a small starting estimate number for use in a low-complexity I244 ^ 27 ^ twf.doc / 006 connected character code decoder. According to the results of computer simulation, the best decoding performance can be achieved when M = 2 or 3. This small number can easily be achieved with today's technology. Although the above focuses on the 802.1 1b CCK connected character code decoder 25 for ii Mbps mode, which uses 256 cCK character codes in its codebook, those skilled in the art can easily use the same Principles and receiver architecture to decode 802.11b cck operating in 5.5 Mbps mode. These techniques actually use a sub-set of 16 CCK characters in a codebook containing 256 character codes. The following examples are illustrations of the programs # 1 and # 2. Fig. 6 shows the steps of the program # 1, and Fig. 7 shows the steps of the program # 2. The figures provided in the following examples are for illustration purposes only and are not actual information. In Fig. 6, there are 256 CCK character code candidates, and each column in Fig. 6 is used to represent the result of each 256 CCK character code candidates. The first line is used to provide the index m of each CCK character code. The second line shows the correlation output of the CCK correlator module 36b, which is used for the k-th CCK character code. The third line shows the pre-calculated FMIC deviation obtained from the FMIC deviation calculation means 36a. The fourth line shows step 1 of procedure # 1 for the output of the second and third lines. The fifth line shows step 2 of program # 1. According to the ICI correction correlation output shown in the fourth line, the fifth line shows that the Mk (Mk = 3) candidates for the start of the k-th character code (who are upset in FIG. 6) are already 254 and Already. The last three lines (sixth, seventh, and eighth lines) in FIG. 6 show step 3 of program # 1. For the k + 1th character code, steps 1 and 2 are actually repeated to determine the starting Mk +1 (Mk + 1 = 3) candidates and 31 I244 ^ 794wf.doc / 006 is used for the k + 1th character code. Here, the FMIC deviation used in step 3 is the same as that set in the third line of FIG. 6 previously. As a result of step 3, the Mk + 1 (Mk + 1 = 3) candidate for the start of the k + 1th character code is equal to £. , £ 253 and circled). It should be noted throughout the example that every number that is absent from the equation Re {} is mathematically correct. The first line in FIG. 7 shows the index Mk. All other lines are either used to display step # 2 of program # 2 or are displayed as substeps of program # 2. In detail, the second line shows the step (la) of program # 2, starting from the three for the kth sub-code (with i as the index 'and i = 1, 2, 3 (= Mk)) One of the character code candidates (仏, ^ 254, and G), we use each for the k + 1th character code (using j as the index 'and j = 1, 2, 3 (= Mk + 1) ) 3 starting character code candidates (^: ,, ^ 253, and G) to calculate the multipath interference caused by the next character code. The third line shows step (lb), where j indicates that the corresponding minimum 値 'in step (la) is selected as one of the three starting candidates for the k-th character code. Taking the first character candidate ^ as an example, the results obtained in step (la) (1.1 · 0.5 and -0.2) are compared, and the minimum 値 (-0.2) is determined (as shown in Figure 7).圏 起 者). For each starting candidate for the k-th character code, this minimum is due to the multipath interference estimation of the next CCK character code. The fourth line shows step (lc). In step (lc), the multi-path interference caused by the next character code (k + 1th CCK character code) is determined by subtracting from the iki correction output pki to obtain Qki. The starting candidate for the k-th CCK character code. In this embodiment, Qu = 9.2, Qk, 9.4, and Qk3 = 7.9. The fifth line shows step (2a) in program # 2. As the k-1th CCK character code has been decoded (the k-1th CCK character code is not labeled Q j, we can use 32 1244275 12976twf.doc / 006 for each k-th character The starting candidate of the code is calculated as the multipath interference caused by the previous CCK character code, as follows: γη Α // Λ _rH rh r γη Α // Λ a rH r ^ k- \ Dup ^ k, 2 In this embodiment, their numbers can be found as 0.2, -1, and 0.6, respectively. The sixth line shows steps (2b) and 3. In step (2b), each is used for the kth The starting candidate for each CCK character code is the multipath interference caused by the previous CCK character code is subtracted from Qkii to obtain Wk> 1. In this embodiment, Wk> 1 = 9, Wk, 2 = 10.4 and Wk, 3 = 7.3. Wk ,, represents the associated output with all multipath interference corrections for each start candidate for the k-th CCK character code. In step (3), the k-th The character code is decoded. In this embodiment, it is determined that Wk2 (circled in FIG. 7) in all multipath interference corrections is the largest associated output, which has. Therefore, the decoded character code is Α = Α, 2 = ς254, and the decoded data is 11111110 'which is a binary representation of 254. Although the present invention has been disclosed as above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art will not depart from the present invention. Within the spirit and scope, some changes and retouching can be made, so the protection scope of the present invention shall be determined by the scope of the attached patent application. [Simplified illustration of the drawing] Figure 1 shows an 802.llb packet Format. Figure 2 is a schematic diagram of a receiver according to an embodiment of the present invention. Figure 3 is a schematic diagram of a conventional multipath strength according to a multipath propagation channel (ie, a channel impulse response diagram). 33 1244275 12976twf .doc / 006 Figure 4 shows the mixed channel impulse response (CIR) diagram after RAKE. Figure 5 shows the schematic diagram of all multipath components in the received signal after RAKE. Figures 6 and 7 show One embodiment of the invention is a flowchart of a method for reducing multipath interference encounters using the current CCK character code. [Schematic description] 22: Selector 24: Channel impulse response judgment device 25: Connected A character code decoder 28: channel matched filter 36a: FMIC deviation calculating means 36b: CCK correlator module 34
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| US4751734A (en) * | 1987-06-01 | 1988-06-14 | Broadcast Technology Partners | Receiver for FM stereophonic broadcasting system utilizing circuits for reducing effects of multipath |
| US5249233A (en) * | 1992-04-06 | 1993-09-28 | Ford Motor Company | Multipath noise minimizer for radio receiver |
| FI100041B (en) * | 1995-12-29 | 1997-08-29 | Nokia Telecommunications Oy | Procedure for estimating signal and noise quality as well as receivers |
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2004
- 2004-02-25 TW TW93104719A patent/TWI244275B/en not_active IP Right Cessation
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| Publication number | Publication date |
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| CN1551543A (en) | 2004-12-01 |
| TW200418275A (en) | 2004-09-16 |
| CN1333540C (en) | 2007-08-22 |
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