TW561711B - RAKE receiver with embedded decision feedback equalizer - Google Patents
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561711 A7 __ ___ B7 五、發明説明(i ) 相關應用 本專利申請案為1999年6月29日提出申請,名稱為,’Rake Receiver With Embedded Decision Feedback Equalizer” 的美國 申請案序號09/342,583之接續申請案,其在此併入當成參 考。 發明領域: 一般來說本發明與無線通訊系統有關,像是但不受限於 然線區域網路(WLAN),尤其是直接與新式改良過的raKE 接收器有關’該接收器包含一嵌入式決策回授等化器 (DFE),可在不損失對於熱噪訊的耐用度之下增加對於(室 内WLAN)多路徑失真的容忍度。 發明背景: 目前較快速(較高資料速率)的無線通訊產品需求是在牽涉 到使用頻譜2.4 GHz部分新標準的IEEE 802.11委員會之前許 多提案的目標,FCC Part 15.247要求使用展頻技術來實施該 新標準’其可讓内部封包資料速率超過1〇 Mbps乙太網路速 度。目前802.11標準使用頻率跳躍(FH)或直接序列(DS)展 頻(S S)技術目前只涵蓋一或二μ p b s的資料速率,F C C要求 使用取自原有S S特性優點的展頻信號,利用降低平均傳輸 功率空間密度來讓信號更能忍受粗心的干擾,並且透過利 用空間冗餘的接收器技術並藉此對抗多路徑失真產生的自 我干擾。 如圖1内所示,傳輸信號的功率延遲圖(PDF) 1〇會因為室 内W L A N系統内的多路徑失真(像是圖2内說明的複雜度降 _-4 -___ 本紙張尺度適用中國國家標準(CNS) A4規格(210X297公釐) 五、發明説明(2 低範例),而展現出大量地降冪穴叮旧幼衰減特性。驅動此 行為的至内傳輸環境實際情況是建築物内位於發射器位置 1 4 /、接收态位置丨5之間相當大量的反射板(例如牆壁),像 疋所示的節點1 2和1 j,以及伴隨個別較後到達時間傳播路 k 11、h與h的傳播損失,其包含呈現對數減弱的能量。 信號的功率延遲圖為有關其功率隨時間消散的平均信號 功率之變化,信號的平均功率位準構成其對應汉吓以辿分量 的不一致。降冪多路徑影響的主要原理方面是,由於事實 上信號的傳播延遲與行進的總距離成正比,如此在平均 上,最強的(所含的阻礙物最少)傳輸路徑就是信號最早到達 接收器的路仅。在已知的隨機發生過程中,從發射器位置 14到接收器位置15的首先到達、直接或視線路徑可能會遇 到衰減媒體(像是一或多道建築物牆壁等等),而由高反射表 面所反射並且沒有遇到衰減媒體的稍後到達信號可能有比 首先到達信號還要大的脈衝反應(CIR)。不過平均而言,對 於追隨CIR峰值之後的回音信號數量來說,這鮮少發生。 在實際應用方面,小型辦公室以及家庭辦公室(s〇H〇)環 i兄的多路徑通道之均方根(RMS)延遲擴展範圍在2〇-5〇 nsec,商業環境則為5(M〇〇 nsec,而工廠環境則為1⑼·2〇〇 nsec。對於降冪衰減通道而言,降冪衰退常數等krms延 遲擴展。對於相當低的信號頻寬而言(小於i MHz),多路徑 造成的衰減通常「很平均」。不過在頻寬大於〖1^七時(例 如直接序列展頻(DSSS)系統所需1〇 MHz頻寬以維持上述參 考說明的10 Mbps較高資料速率),衰減就會因頻率而異,對 本纸張尺度適用中國國家標準(CNS)八4規格(21〇x297公釐) 3 五、發明説明( 产… 靠的通訊構成嚴重的阻礙。如此, 〜二的夕路徑失真可導致㈣頻帶上嚴重的傳播損失。 對^此嚴重頻率選擇多路徑失真問題的較佳機制是 =正接收器。:俗稱為「耙式(rake)」接收器。為了成 、KE接收讀作,就必須要使用傳輸頻寬 大於;m頻 _SS結構。在Dsss信號結構内,個別碼字是由一系 列PN碼「片碼」所形成,在此運用「石馬字」一詞,而非 :符號」、,來避免「片L馬字之間造成混淆。利用像 疋QPSK&種相當簡單的調變法則就可傳送片碼,並 且碼子片碼可m定在記號順序内,或可為假隨機。 此外’妈字的相位調變可用來傳送資訊,換言之,若每 個碼字要添加額外的資訊位元,則要轉移碼字的相位。例 如兩額外的位元可用來提供正交(九十度)相位轉移增加: 〇 、90。、180。與270。。碼字的片碼可選自於多碼字集, Μ位元可從構成多碼字集的N碼字中選出特定碼字。這種法 則的範例是使用用於碼字集的Walsh*HadamarcU4。對於 上述參考說明的2.4 01^頻譜而言,汨££8〇211標準委員會 提議使用8位元編碼法則,其中位置位元從N = 6 4多片碼碼 字中選擇其一,並且剩餘的兩位元定義選取碼字的四個可 能(正交)相位之一。 如圖3内的圖示說明’在頻道匹配修正或rake接收器 内’所接收的(擴展)信號會耗合至碼字修正器31 ,其輸出 (顯示為一序列到達時間脈衝3 2-1、32-2、32-3)則供應至 連貫多路徑結合器3 3。該碼字修正器3 1包含複數個修正 本紙張尺度適用中國a家搮準(CNS) A4規格(210X 297公I) 561711 A7561711 A7 __ ___ B7 V. Description of the Invention (i) Related Applications This patent application was filed on June 29, 1999, and is a continuation of US Application Serial No. 09 / 342,583 entitled "Rake Receiver With Embedded Decision Feedback Equalizer" Applications are hereby incorporated by reference. Field of the Invention: The present invention is generally related to wireless communication systems, such as, but not limited to, wireless local area network (WLAN), and especially directly to the newly improved raKE Receiver related 'The receiver includes an embedded decision feedback equalizer (DFE), which can increase the tolerance to (indoor WLAN) multipath distortion without losing the durability to thermal noise. BACKGROUND OF THE INVENTION: The current demand for faster (higher data rate) wireless communication products is the goal of many proposals before the IEEE 802.11 committee that uses the new standard for the 2.4 GHz portion of the spectrum. FCC Part 15.247 requires the use of spread spectrum technology to implement the new standard. Allows internal packet data rates to exceed 10 Mbps Ethernet speed. Current 802.11 standards use frequency hopping (FH) or direct sequence (DS) Frequency (SS) technology currently only covers one or two μ pbs data rates. The FCC requires the use of spread-spectrum signals derived from the advantages of the original SS characteristics, and reduces the average transmission power space density to make the signal more tolerant of careless interference, and Through the use of spatially redundant receiver technology and thereby counteracting self-interference caused by multipath distortion. As shown in Figure 1, the power delay diagram (PDF) of the transmitted signal 10 will be due to multipath distortion in the indoor WLAN system ( Such as the complexity reduction illustrated in Figure 2 _-4 -___ This paper size applies the Chinese National Standard (CNS) A4 specification (210X297 mm) 5. Description of the invention (2 low example), and shows a large number of power reduction points The old and young attenuation characteristics. The actual situation of the inward transmission environment driving this behavior is that there are a large number of reflectors (such as walls) between the transmitter position 1 4 / and the receiving position 丨 5 in the building, as shown by 疋Nodes 1 2 and 1 j, and the propagation losses associated with individual later arrival time propagation paths k 11, h, and h, include energy that exhibits a logarithmic decrease. The power delay diagram of a signal is related to its power as a function of The average power level of the signal dissipates from time to time, and the average power level of the signal constitutes the inconsistency of its corresponding component. The main principle aspect of the power reduction multipath effect is that, due to the fact that the propagation delay of the signal and the total distance traveled Proportionally, so on average, the strongest (with the fewest obstacles) transmission path is the path where the signal reaches the receiver only. In the known random occurrence process, the first from transmitter position 14 to receiver position 15 Reaching, direct, or sight paths may encounter attenuating media (such as one or more building walls, etc.), and later arriving signals that are reflected by highly reflective surfaces and do not encounter attenuating media may be better than the first arriving signal Even greater impulse response (CIR). On average, however, this rarely happens for the number of echo signals following a CIR peak. In terms of practical application, the root mean square (RMS) delay of the multi-path channel of the small office and the home office (SOHO) ring extension range is 20-50ns, while the business environment is 5 (MO). nsec, and the factory environment is 1⑼ · 200nsec. For reduced-power attenuation channels, krms delay expansion such as reduced-power decay constant. For relatively low signal bandwidth (less than i MHz), multipath caused Attenuation is usually "very average". However, when the bandwidth is greater than 1 ^ 7 (for example, a 10 MHz bandwidth required by a DSSS system to maintain the higher data rate of 10 Mbps described above) It will vary according to the frequency, and the Chinese National Standard (CNS) 8-4 specification (21 × 297 mm) is applied to the paper size. 3 V. Description of the invention (Production ... Reliable communication constitutes a serious obstacle. In this way, the path to the second night Distortion can cause severe propagation loss in the chirp band. The preferred mechanism for this severe frequency selection multipath distortion problem is = positive receiver .: Commonly known as a "rake" receiver. In order to be successful, KE receives read Operation, you must use the transmission frequency Greater than; m frequency _SS structure. In the Dsss signal structure, individual code words are formed by a series of PN code "chip codes". Here, the word "shima" is used instead of the "symbol" to avoid "There is a confusion between the L and Ma characters. The chip code can be transmitted using a fairly simple modulation rule like 疋 QPSK & and the chip chip code can be set in the order of the marks, or it can be pseudo-random. Word phase modulation can be used to convey information. In other words, if additional code bits are added to each codeword, the phase of the codeword is shifted. For example, two extra bits can be used to provide a quadrature (90 degree) phase Transfer increase: 0, 90, 180, and 270 ... The chip code of the codeword can be selected from the multicodeword set, and the M bit can select a specific codeword from the N codewords constituting the multicodeword set. An example of the rule is the use of Walsh * HadamarcU4 for the codeword set. For the 2.4 01 ^ spectrum of the above-mentioned reference, 8 £ 8,021 The Standards Committee proposes the use of an 8-bit coding rule, where the position bits are from N = Choose one of 6 4 multi-chip code words, and the remaining two bits define One of the four possible (orthogonal) phases of the codeword. As shown in the illustration in Figure 3, the received (extended) signal 'in the channel matching correction or rake receiver' will be consumed by the codeword corrector 31, The output (shown as a sequence of time-of-arrival pulses 3 2-1, 32-2, 32-3) is supplied to a continuous multipath combiner 3 3. The codeword corrector 3 1 contains multiple corrections. a Home Standard (CNS) A4 Specification (210X 297 Male I) 561711 A7
561711 A7 B7561711 A7 B7
五、發明説明(5 有脈衝自動修正函數以及零交叉修正函數的碼字。 此外,對於重要用途的多路徑而言,為了將中間碼字干 擾造成的退化降至最低,碼字長度必須非常大(例如在以、 128、256或以上之階數,像是用於軍事用途上)。不過,在 商業環境中’每個瑪字的片碼數量必須受到限制,以將可 用資料頻寬表大化。因為當每個碼字的片碼數量減少時, 碼字溢出的内容就會增加,如此多路徑失真就會很明顯, 所以非常小的碼字片碼密度就可導致碼字能量溢出/洩漏過 多路徑碼字。因此,問題就是要如何將使用這種比較差理 想碼字的RAKE接收器之輸出噪訊比最佳化。 發明概要· 依照本發明,由嵌入式RAKE接收器架構可成功指出此問 題,其中該接收器包含嵌入在到達接收器頻道匹配遽波器 以及碼字修正器的信號處理路徑上之片碼式決策回授等化 器(DFE)結構。此決策回授等化器用來降低或消除兩種受限 片碼長度碼字在使用多路徑頻道輸送時會遭受到的失真。 第一種是個別碼字CWi以及其他碼字cwi+j内的能量「流 出」或洩漏,第二種失真是個別碼字的片碼内能量之「污 損」。 決桌回授荨化器特別適合用於對抗WLAN内的室内多路 徑失真,因為這種多路徑失***要是最小的相位,最強的 信號分量幾乎總是最早抵達,而較弱的分量則較慢抵達。 因此’大多數多路徑失真在頻道脈衝反應上都呈現出「尾 巴」退化情況。再者,D F E的回授分接理想上可用來對抗 本紙張尺度適用中國國豕標準(CNS) A4規格(210 X 297公爱) 6 6 五 、發明説明 最小相位夕路從失真,而正授分接則用來對抗最大相位分 量。結果,用於對抗室内多路徑的£){7£;幾乎不需要正授分 接,大多數4理都纟回授分接内執彳。料在基頻上實施 DFE正授分接需要全複合多卫器,而當運用QpsK元件時回 授分接只需要複合加法與減法,實施複雜並非很重要的問 題。 雖然將DFE嵌入RAKE接收器可輕易對抗室内多路徑, 其在一片碼上做決策,因此需要相當高的snr。回授分接 為除了長退化多路徑回音尾巴並且可跨越多路徑碼字,如 此就可取消中間片碼污損以及中間碼字溢出。碼字修正器 利用連續結合碼字的軟決策片碼來改善噪訊比。雖然做出 了 DFE片碼決策錯誤,但是碼字修正器還是可以利用連續 結合所有碼字的片碼來做出正確決策。 對於降低嗓訊比而言,決策喊等化器㈣誤的傳播會 導致在叢集内發生·.片碼錯誤,若用於設定等化器分接係數 的軟片碼決策不正確,DFE*接加權特性將會迅速惡化, 避免多路徑失真補償。若要處理低SNR,在進行硬決策之 前會先試驗所接收的所有碼字片碼。利用為每個已經傳送 的碼子產生D F E式修正偵測統計就可達成此目的。利用執 行碼字片碼的回授等化可產生潛在已傳送石馬字的谓測統 計,假定碼字真的已經傳送了。 「用於取消中間碼字干擾的DFE嵌入式信號處理架構可 「圍繞」碼字修正器,在這種架構内,頻道匹配濾波器將 與在消除頻道脈衝反應時產生的後游標代表回音差異結合 五、發明説明(7 j起#果會產生「乾淨的」接收碼字副本,該碼字轉 。至RAKE接收器的碼字修正器。該修正器的輸出會耦合至 碼字決策運算子,該碼字決策運算子會檢驗已接收碼字内 7有片碼’來做出哪個碼字已確實傳送的決策。碼字的決 '、來&成片碼内谷的複製品以及傳輸碼字的相位資訊, 然後合成的財會與FIR濾波器内實施的頻道脈衝反應評估 相結合’以便在由頻道匹配m所接收的信號内產生後 游標多路徑回音之代表。 右要取消個別碼字片碼内能量的中間碼字片碼污損,至 每個別碼字修正器的信號處理分支將言史定成會將組成每一 已接收碼字的所有片碼内容與個別不同組的碼字伴隨^^£ 回授/刀接之一差異結合在一起,這代表在從發射器經過多 路咎頻道傳輸過路徑的特定碼字將經歷過這後游標多路徑 失_回a在碼子修正益的上游或下游都可去除該後游標 多路徑失真。 ' 在上游的實施例中,每個連續接收的碼字片碼集都會耦 合至複數個碼字修正器統計分支,而每個分支都伴隨不同 的碼字。就使用八位元欄位的無限制範例而言,其有 K/256碼字組合(包含26 = 64碼字,每個QpSK編碼都有 22 = 4可能的正交相位(0。、9〇。、18〇。、27〇。))。在個別碼 字修正器分支内,接收的信號路徑會與FIR濾波器回授分接 集的輸出差異結合,合成其個別碼字片碼集的多路徑頻道 脈衝回應(例如在本範例中每個字碼都由八個片碼組成),如 此可產生碼字片碼集的後游標多路徑回音之代表。藉由從 -10 - 本紙張尺度適用中國®家標準(CNS) A4規格(210X297公釐) 561711 五、發明説明(8 接收的碼字中減去合成的後游標多路徑回音,則至伴隨分 支碼字修正器的輸入是有效的接收碼字片碼集「清晰」 版,其已經去除了多路徑式片碼污損。每個碼字修正器的 輸出㈣合至峰值積測器,該债測器會選擇最大的輸出當 成傳輸碼字。 有一種更有效的法則來合成多路徑頻道脈衝反應,就是 利用從每個字碼修正n下游所接收的信號中減去個別fir回 授濾波器分接級。為了簡化複雜度起見,碼字修正器可當 成快速Walsh (Hadamard)結構來實施,因為不同的接收信號 處理路徑和回授分接之結合為後修正操作,所以在每^新^ 接收的碼字片石馬集計時進入修正器時並不需要重新產生回 授分接。#此藉由允許將合成分接路徑功能性餘存在查找 表内,將可減少實施複雜度。 圖式簡單說明: 圖1顯示伴隨室内WLAN系統多路徑失真的功率延遲圖; 圖2說明在發射器位置與接收器位置之間具有複數個反射 器的室内WLAN系統之簡化範例; 圖3說明傳統的RAKE接收器; 圖4顯示圖MRAKE接收器,其中由頻道匹配遽波器(連 貫多路徑結合器)與碼字修正器所執行的操作順序變成相 反; 圖5顯示傳輸過多路徑WLAN頻道的受限片碼長度碼字之V. Description of the invention (5 Codewords with automatic pulse correction function and zero-crossing correction function. In addition, for important multipaths, in order to minimize the degradation caused by intermediate codeword interference, the codeword length must be very large (For example, in the order of 128, 256, or more, such as for military use.) However, in a commercial environment, the number of chips per mark must be limited in order to increase the available data bandwidth. Because when the number of chips per codeword decreases, the content of codeword overflow will increase, so multipath distortion will be obvious, so very small codeword chip density can cause codeword energy overflow / Too many path codewords are leaking. Therefore, the question is how to optimize the output noise ratio of a RAKE receiver using such a relatively poor ideal codeword. SUMMARY OF THE INVENTION According to the present invention, the embedded RAKE receiver architecture can be successful Point out the problem, where the receiver includes a chip-coded decision feedback equalizer embedded in the signal processing path to the receiver channel matching waver and codeword corrector (D FE) structure. This decision feedback equalizer is used to reduce or eliminate the distortion that two restricted chip code length codewords will suffer when using multipath channel transmission. The first is the individual codeword CWi and other codewords cwi The energy in + j "flows out" or leaks. The second kind of distortion is the "fouling" of the energy in the chip code of the individual codeword. The final table feedback network adapter is particularly suitable for combating indoor multipath distortion in WLAN. Because this multipath distortion is mainly the smallest phase, the strongest signal components almost always arrive earliest, while the weaker components arrive more slowly. Therefore, 'Most multipath distortions show a "tail" on the channel pulse response. Degradation. In addition, the feedback tapping of DFE can ideally be used to resist the Chinese paper standard (CNS) A4 specification (210 X 297 public love) of this paper size. The forward tap is used to oppose the maximum phase component. As a result, it is used to counter indoor multipath £) {7 £; almost no positive tap is required, and most of the four processes are performed within the feedback tap. It is expected that the implementation of DFE forward transfer taps at the base frequency requires a full-composite multiplexer, and when QpsK components are used, the feedback taps only require composite addition and subtraction, and implementation is not a very important issue. Although embedding a DFE into a RAKE receiver can easily combat indoor multipath, it makes decisions on a single chip and therefore requires a relatively high snr. Feedback tapping is in addition to long degraded multi-path echo tails and can span multi-path codewords, thus eliminating intermediate chip code fouling and intermediate codeword overflow. The codeword modifier uses a soft decision chip code that continuously combines codewords to improve the noise ratio. Although the DFE chip code decision error is made, the codeword corrector can still use chip codes that continuously combine all codewords to make the correct decision. For the reduction of the voice ratio, the wrong propagation of the equalizer of decision-making will result in cluster errors in the cluster. If the decision of the soft-chip code used to set the equalizer tap coefficient is incorrect, the DFE * will be weighted. The characteristics will deteriorate rapidly, avoiding multipath distortion compensation. To handle low SNR, all codeword chips received are tested before making a hard decision. This can be achieved by generating D F E-type modified detection statistics for each transmitted code. Performing feedback equalization by performing codeword chip code generation can generate predicate statistics for potentially transmitted shima words, assuming that the codeword has actually been transmitted. "The DFE embedded signal processing architecture for canceling intermediate codeword interference can" round "the codeword modifier. In this architecture, the channel matching filter will be combined with the post-cursor representative echo difference generated when the channel pulse response is eliminated. V. Description of the invention (from 7 j onwards #results will produce a "clean" copy of the received codeword, which codeword is transferred to the codeword modifier of the RAKE receiver. The output of this modifier will be coupled to the codeword decision operator, The codeword decision operator will check that there are 7 chip codes in the received codeword to make a decision as to which codeword has actually been transmitted. The decision of the codeword, come & make a copy of the chip valley and the transmission code The phase information of the word is then combined with the channel impulse response evaluation implemented in the FIR filter in order to generate a representation of the multi-path echo of the post-cursor in the signal received by the channel match m. Right to cancel individual codewords The intermediate code word chip code of the energy in the code is defaced. The signal processing branch of each codeword corrector determines the history of all chip code contents and each different group of codes that make up each received codeword. Along with the difference between feedback and knife connection, this means that the specific codeword of the path transmitted from the transmitter through the multi-channel channel will experience the multi-path loss of the cursor after this. The upstream multi-path distortion can be removed upstream or downstream. ′ In the upstream embodiment, each successively received codeword chip set is coupled to a plurality of codeword modifier statistical branches, and each branch is Accompanying different codewords. For an unlimited example using an octet field, it has a K / 256 codeword combination (containing 26 = 64 codewords, each QpSK code has 22 = 4 possible quadrature phases (0., 90., 18 .., 27.)). Within the branch of the individual codeword modifier, the received signal path will be combined with the output difference of the FIR filter feedback tap set to synthesize its individual code. The multi-path channel impulse response of the chip code set (for example, in this example, each code is composed of eight chip codes), which can generate a representative multi-path echo of the code word chip code set. -This paper size applies to China® Home Standard (CNS) A4 (210X 297 mm) 561711 V. Description of the invention (8 The synthesized post-cursor multi-path echo is subtracted from the received codeword, and the input to the accompanying codec modifier is a valid "clear" version of the received codeword chip set. It has removed the multi-path chip code fouling. The output of each codeword corrector is combined with the peak integrator, which will select the largest output as the transmission codeword. There is a more effective rule to synthesize The multipath channel impulse response is to subtract individual fir feedback filter tap stages from the signal received downstream of each word correction n. To simplify complexity, the code word corrector can be used as a fast Walsh (Hadamard) The structure is implemented, because the combination of different received signal processing paths and feedback taps is a post-correction operation, so it is not necessary to re-generate the feedback taps every time when the received codeword chip stone horse timing enters the corrector. . #This will reduce implementation complexity by allowing the remaining functionalities of the synthetic tap path to be stored in a lookup table. Brief description of the drawings: Figure 1 shows a power delay diagram with multipath distortion of an indoor WLAN system; Figure 2 illustrates a simplified example of an indoor WLAN system with a plurality of reflectors between a transmitter position and a receiver position; Figure 3 illustrates a conventional RAKE receiver; Figure 4 shows the MRAKE receiver, in which the sequence of operations performed by the channel matching waver (coherent multipath combiner) and the codeword corrector becomes reversed; Figure 5 shows the impact of transmitting too many paths on the WLAN channel Limit code length codeword
序列部分; X 圖6說明具有在到連貫多路徑結合器遽波器與碼字修正器 561711 A7 ______B7 五、發明説明(9 ) 的信號處理路徑内嵌入決策回授等化器之{1八仄£接收器; 圖7說明決策回授等化器; 圖8說明圖6的RAKE接收器,該接收器包含圖7的決策回 授等化器結構; 圖9顯示多路徑脈衝反應特性; 圖1 0說明用於取消多路徑式中間碼字干擾(丨s丨)的D F E嵌 入式信號處理架構; 圖11說明用於RAKE接收器的傳統碼字修正器; 圖1 2 #明用於去除碼字修正器上游的後游標多路徑失真 之信號處理架構;以及 圖1 3說明用於去除碼字修正器下游的後游標多路徑失真 之信號處理架構。 圖1 4說明圖1 3的信號處理架構更一般的具體實施例。 發明詳細說明: 在詳細說明本發明的新式改良過的嵌入式DFE RAKE接 收器架構之前,吾人可觀察到本發明的接收器架構主要還 是使用傳統數位通訊電路以及伴隨數位信號處理元件的調 變器配置,以及伴隨的監督控制電路,因此可控制這種電 路與組件的操作。吾人也可了解到,本發明適用於任何碼 字調變的直接序列展頻(D S S S)信號,包含互補碼。在實際 併入現有無線通訊設備印刷電路卡的實施中,本發明可經 意實施成場域可程式閘極陣列(FPGA),或應用待定積體電 路(ASIC)晶片組。 因此,這種電路以及組件的配置架構以及其與其他通訊 -12 - I紙張尺度適用中國國家搮準(CNS) A4規格(210 X 297公釐) ~ ' — 561711 A7 B7 五、發明説明(1〇 設備的介面方式都說明在可輕易了解的方塊圖中(就大多數 而言),其只詳細顯示有關本發明的部分,所以不會含糊不 清,可讓精通此技藝的人士輕易了解此處說明的利益。因 此,方塊圖將以傳統功能分組方式來顯示本發明的主要組 件,如此可更輕易了解本發明。 為了明瞭本發明DFE嵌入式RAKE接收器所提供的改 善,所以一開始最好說明本發明所遇到的有限片碼長度直 接序列展頻碼字的失真影響。 圖5顯示傳輸過多路徑WLAN頻道的受限片碼長度直接序 列展頻碼字(CW)·.·、50-1、50-2、50-3、·.·之序列部 分。在傳輸期間,用通道傳送的片碼會產生兩種失真··中 間碼字溢出以及内部碼字片碼污損。前一種結果顯示為 51,是個別碼字CWi以及其他碼字cwi + j·内的能量「流出」 或洩漏’第二種失真形式是個別碼字的片碼内能量之「污 損」。 此問題的解決方$,如圖6内所示,是利用在連貫多路徑 結合器(頻道匹配濾波器)3 3以及碼字修正器3 ][之間的信號 處理路徑上安裝片碼式決策回授等化器(DFE)36,來修改 Rake接收器。決策回授等化器的基本組態顯示在圖7内(包 含多分接延遲線設定的有限脈衝反應(FIR)濾波器結構), 包含複數個正授分接7 1,信號傳輸路徑耦合至差異結合器 73的第一輸入72,並具有耦合來接收一組回授分接乃的輸 出之第一輸入74。差異結合器73的輸出會耦合至決策單元 76,而此單元的輸出則轉合至回授分接75。圖8說明圖6的 不紙張尺度通财® S家標準(CNS) A4規格(〗1G X 29^董Γ--------- 561711Sequence part; X Figure 6 illustrates {1 八 仄 having a decision feedback equalizer embedded in the signal processing path of the invention description (9) in the signal processing path to the coherent multipath combiner waver and codeword corrector 561711 A7 ______B7 £ Receiver; Figure 7 illustrates the decision feedback equalizer; Figure 8 illustrates the RAKE receiver of Figure 6, which includes the decision feedback equalizer structure of Figure 7; Figure 9 shows the multipath pulse response characteristics; Figure 1 0 illustrates the DFE embedded signal processing architecture for canceling multi-path intermediate codeword interference (丨 s 丨); Figure 11 illustrates the traditional codeword corrector for RAKE receivers; Figure 1 2 # Ming for removing codewords Signal processing architecture for post-cursor multipath distortion upstream of the corrector; and FIG. 13 illustrates a signal processing architecture for removing post-cursor multipath distortion downstream of the codeword corrector. FIG. 14 illustrates a more general embodiment of the signal processing architecture of FIG. 13. Detailed description of the invention: Before explaining the new and improved embedded DFE RAKE receiver architecture of the present invention in detail, we can observe that the receiver architecture of the present invention mainly uses traditional digital communication circuits and modulators with digital signal processing elements. The configuration, and the accompanying supervisory control circuits, control the operation of such circuits and components. I can also understand that the present invention is applicable to direct sequence spread spectrum (DSSS) signals with any codeword modulation, including complementary codes. In the implementation of actually incorporating a printed circuit card of an existing wireless communication device, the present invention can be implemented as a field programmable gate array (FPGA) or an application-determined integrated circuit (ASIC) chipset. Therefore, the configuration structure of this circuit and components and its communication with other -12-I paper standards are applicable to China National Standards (CNS) A4 specifications (210 X 297 mm) ~ '— 561711 A7 B7 V. Description of the invention (1 〇 The interface of the device is described in an easily understandable block diagram (for the most part), which only shows the part of the invention in detail, so it is not ambiguous, and it can be easily understood by those skilled in the art. The benefits are described here. Therefore, the block diagram will show the main components of the present invention in a traditional functional grouping, so that the present invention can be more easily understood. In order to understand the improvements provided by the DFE embedded RAKE receiver of the present invention, It is easy to illustrate the distortion effect of the direct chip spread spectrum codeword with finite chip length encountered in the present invention. Fig. 5 shows the direct chip spread spectrum codewords (CW) with limited chip code length (CW) that transmit too many paths WLAN channels .., 50 -1, 50-2, 50-3, ..... During the transmission, the chip code transmitted by the channel will produce two kinds of distortion ... The intermediate codeword overflows and the internal codeword chip code is dirty. The former Knot If the result is shown as 51, it is the energy “outflow” or leakage in the individual codewords CWi and other codewords cwi + j. The second distortion form is the “fouling” of the energy in the chip code of the individual codeword. The solution $, as shown in Figure 6, is to use chip-type decision feedback on the signal processing path between the coherent multi-path combiner (channel matching filter) 3 3 and the code word corrector 3] [ Modifier (DFE) 36 to modify the Rake receiver. The basic configuration of the decision feedback equalizer is shown in Figure 7 (including the structure of a finite impulse response (FIR) filter with multiple tapped delay line settings), including a plurality of Positive-feed tap 71, the signal transmission path is coupled to the first input 72 of the differential coupler 73 and has a first input 74 coupled to receive the output of a set of feedback taps. The output of the differential coupler 73 is coupled To decision unit 76, and the output of this unit is transferred to feedback tap 75. Figure 8 illustrates the paperless standard of the financial system in Figure 6® S Home Standard (CNS) A4 specifications (〖1G X 29 ^ 董 Γ-- ------- 561711
RAKE接收态,該接收器併入圖7的決策回授等化器結構。 在軟、等化的片碼位準供應至碼字修正器31之前,可操作 此信號處f架構來DFE等化該片碼。為了有效的信號處 理,DFE前端的頻道匹配濾波器33與正授分接區段7丨可在 合成結構内實施,當成「白化」匹配濾波器。如破折線77 所示。 有兩個主要因素支持決策回授等化器特別適合對抗室内 多路徑,首先,多路徑失***要是最小的相位,因為最強 的化號分量會首先抵達,而較弱的分量則稍後抵達。如圖 别回說明的,請參考圖丨的指數功率下降特性,稍後抵達的 (多路徑)分量會相當弱,所以大多數多路徑失真會像是「尾 巴」衰減出現在頻道脈衝反應上。 第二,DFE的回授分接理想上可用來對抗最小相位多路 徑分量’而正授分接則用來對抗最大相位分量。結果,用 於對抗室内多路徑的DFE幾乎不需要正授分接,大多數處 理都在回授分接内執行。因為實施基頻上DFE的正授分接 需要用到全複合多工器,而當運用qPSK元件時回授分接只 需要複合加法與減法,所以為了實際應用,較好使用主要 用回授分接的實施。 圖9顯示最大脈衝反應組件的多路徑脈衝反應特性。通 常DFE的決策單元會集中在脈衝反應的峰值91上,因為其 為具有最大噪訊比的單一組件。回授分接減去緊接在峰值 9 1之後的「尾巴」9 2,而正授分接則取消在峰值之前的前 端脈衝組件93。換言之,在傳統DFE内,取消(中間符號)RAKE receiving state, the receiver incorporates the decision feedback equalizer structure of FIG. Before the soft, equalized chip code level is supplied to the codeword corrector 31, the f architecture at this signal can be operated to DFE equalize the chip code. For effective signal processing, the channel-matching filter 33 and forward tap section 7 in the front end of the DFE can be implemented in a composite structure, which acts as a "whitening" matched filter. This is indicated by the dashed line 77. There are two main factors supporting the decision feedback equalizer that is particularly suitable for combating indoor multipath. First, the multipath distortion is mainly the smallest phase, because the strongest signal component arrives first, and the weaker component arrives later. As shown in the figure, please refer to the exponential power drop characteristic of Figure 丨. The (multipath) component arriving later will be quite weak, so most multipath distortion will appear on the channel pulse response like "tail" attenuation. Secondly, the feedback tap of the DFE is ideally used to counter the minimum phase multipath component 'and the positive tap is used to counter the maximum phase component. As a result, DFEs used to counter indoor multipathing require almost no forward-feeding taps, and most processing is performed within feedback taps. Because the implementation of DFE on the fundamental frequency requires a full compound multiplexer, and when using qPSK components, the feedback tap only requires compound addition and subtraction, so for practical applications, it is better to use the main feedback branch.接 的 应用。 Implementation. Figure 9 shows the multipath pulse response characteristics of a maximum pulse response component. Usually the decision unit of the DFE is focused on the peak value 91 of the impulse response, as it is a single component with the largest noise ratio. The feedback tap is subtracted from the "tail" 9 2 immediately after the peak 9 1, and the forward tap cancels the front-end pulse component 93 before the peak. In other words, in traditional DFE, cancel (middle symbol)
561711561711
干擾牽涉到強迫將脈衝峰值之外的能量變為零。當只使用 回授刀接時,在等化期間並無噪訊放大,所以不需要上述 的後合多工器。如可從圖1所見的,這差不多可用於室内無 線頻道了。 此刻雖然將決策回授等化器併入RAKE接收器是對抗室内 多路徑特別有用的機制,但還是決定於片碼,所以需要有Disturbance involves forcing the energy beyond the peak of the pulse to zero. When only using the feedback knife connection, there is no noise amplification during the equalization period, so the above-mentioned post multiplexer is not needed. As can be seen from Figure 1, this is almost applicable to indoor wireless channels. Although the integration of the decision feedback equalizer into the RAKE receiver is a particularly useful mechanism against indoor multipath at this moment, it is still determined by the chip code, so it is necessary to have
相當高的SNR(例如大於等於1〇dB)才能成功運作。dfe回 授分接75、;肖除了長退化多路徑尾巴92並且可跨越多路徑碼 字,如此就可取消上述的中間片碼污損以及中間碼字溢 出。碼字修正器3 1利用連續結合碼字的軟決策片碼來提供 裝 善.即使做出了 DFE片碼決策錯誤,但是碼字修: ,還是可以利用連續結合所有碼字的片碼來做出正確決 策。 訂A relatively high SNR (e.g., 10 dB or more) is required for successful operation. The dfe feedback tap 75, except for the long degenerate multi-path tail 92, can span multi-path codewords, thus eliminating the above-mentioned intermediate chip code defacement and intermediate codeword overflow. The codeword corrector 31 uses a soft decision chip code that continuously combines codewords to provide installation. Even if a DFE chip code decision is made wrong, but the codeword is modified, you can still use the chip code that continuously combines all codewords to do Make the right decisions. Order
不過,對於降低噪訊比而言,決策回授等化器内錯誤的 傳播會導致在叢集内發生片碼錯誤,若用於設定等化器分 接係數的軟片碼決策不正確,整個DFE分接加權特性將會 迅速惡化,避免多路徑失真補償。換言之,當噪訊等級^ 加,通常在片碼決策破壞之後很快碼字決策就會破壞。 為了解決此低SNR問題,在進行硬決策之前會先試驗所 接收的所有碼字片碼。利用為每個已經傳送的碼字(而非為 每個片碼)產生DFE式谓測統計就可達成此目的。利用執行 碼字片碼的喊等化可產生給定潛在已傳送(”職”)碼字= 偵測統计’假定相關瑪字真的已經傳送了。 如上面所點出的,在傳輸期間,用通道傳送的碼字會產However, in order to reduce the noise ratio, the propagation of errors in the equalizer of decision feedback will cause chip code errors in the cluster. If the decision of the soft chip code used to set the equalizer tap coefficient is incorrect, the entire DFE score will be reduced. The connection weighting characteristics will deteriorate rapidly to avoid multipath distortion compensation. In other words, when the noise level increases, usually the code word decision will be destroyed soon after the chip code decision is destroyed. To address this low SNR problem, all codeword chip codes received are tested before making a hard decision. This can be achieved by generating DFE predicate statistics for each codeword that has been transmitted, rather than for each chip. The use of shout equalization to perform codeword chip code generation can generate a given potentially transmitted ("job") codeword = detection statistics' assuming that the relevant mark has actually been transmitted. As noted above, during transmission, the codewords transmitted over the channel will produce
13 561711 五、發明説明( 生兩種失真:碼字間中間碼字干擾或「溢出」(換言之,中 間符號干擾(ISI)),以及内部碼字片碼干擾(Ici)或個別碼 字片碼CWA能量的污損。ISI的程度與每碼字的片碼數量 以及多路徑失真的範圍有關。對於05§§機制而言,像是運 用在軍事應用之中,每碼字的片碼數量通常比較多(例如 64 1 28、256階或以上),相對碼字溢出比較不顯著。不 過如上所點出的,在商業環境中,每個碼字的片碼數量必 /頁又到限制(例如每妈字只有八個),以將可用資料頻寬最大 化。因為當每個碼字的片碼數量減少肖,碼字溢出的内容 =會增:,如此多路徑失真就會很明顯,所以非常小的碼 子片碼密度不會立即導致溢出連續碼字邊界,但會通過多 路徑碼字。 圖10内所示用於取消中間碼字干擾(ISI)的DFE嵌入式信 號處理架構可「圍繞」碼字修正器,為此目的,頻道匹配 遽波器33的輸出會轉合至差異結合器1〇2的第一輸入⑻, 而該結合器的第二輸入103則耦合用來接收評估頻道脈衝回 應所產生的後游標代表回音。差異結合器1 〇2的輸出(代 表已接收碼字的「乾淨」副本)會轉合至碼字修正器31,該 修正器的輸出則供應至碼字決策運算子1()5。碼字決策運算 子105會檢驗已接收碼字内所有M個片碼而非單一個片碼, 來做出哪個碼字已確實傳送的決策。 —已知,由運算子1G5所得出的碼字決策,然後會在傳輸碼 字合成益106内合成片碼内容複製品以及依照原始傳輸碼字 所决疋的相位資訊。然後合成的碼字會與隱慮波器⑽内 -16 本紙張尺度適财S 8家標準⑽S)A4規格(21()><297公#) 56171! A7 B7 五、發明説明 實施的頻道脈衝反應評估相結合,以便在由頻道匹配濾波 器3 3所接收的信號内產生後游標多路徑回音之代表。藉由 將此後游標回音供應至差異結合器102,則頻道匹配濾波器 33輸出内的總IS][貢獻會有效從給碼字處理器3 1的輸入中取 消。請注意到,在FIR濾波器107内實施的頻道脈衝回應評 估並沒有(碼字)長度限制;不管其穿越過一或複數個碼字邊 界,其輸出涵蓋了由頻道匹配濾波器3 3所接收的信號内整 個後游標多路徑回音。另外,為了有效的信號處理,DFE 的頻道匹配濾波器與正授分接區段可當成「白化」匹配渡 波器來實施,如上面所示。 在此將參考圖1 1 -1 3來說明用於取消個別碼字c Wi片碼内 能量的内部碼字片碼污損之DFE嵌入式信號處理架構。如 圖1 1内所示,傳統RAKE接收器的碼字修正器3 1具有複數 個個別碼字修正器3 1 -1 -3 1-N,每個都用來偵測不同的碼 字片碼集。本範例的八位元欄位定義出2 5 6碼字組合(包含 2 - 64碼子’每個都有22 = 4可能的正交相位(〇。、9〇〇、 180°、270°))。本範例的每個碼字都包含八個片碼,所以 總共有48 = 64K可能的片碼組合,這64種碼字片碼組合都可 選擇。 運用一種先前根據通訊應用(室内WLAN)屬性所做的需 求組,並且製造出降低複雜度實施的修正器,根據經驗一 開始大量的可用片碼組合可減少成只具有上述片碼集結構 的碼字,像是上述般的Walsh或Hadamard結構。即使從實 際觀點來說這種選擇準則可以滿足,但並非所有選取組=13 561711 V. Description of the invention (two kinds of distortion: intermediate codeword interference or "overflow" between codewords (in other words, intermediate symbol interference (ISI)), and internal codeword chip interference (Ici) or individual codeword chip codes CWA energy is defaced. The degree of ISI is related to the number of chips per codeword and the range of multipath distortion. For the 05§§ mechanism, as in military applications, the number of chips per codeword is usually There are many (such as 64 1 28, 256 levels or above), and the relative codeword overflow is relatively insignificant. However, as noted above, in a commercial environment, the number of chips per codeword must be limited per page (such as There are only eight characters per word) to maximize the available data bandwidth. Because when the number of chips per codeword decreases, the content of codeword overflow = will increase: so many path distortions will be obvious, so Very small code chip code density does not immediately cause overflow of consecutive codeword boundaries, but passes through multipath codewords. The DFE embedded signal processing architecture shown in Figure 10 for canceling intermediate codeword interference (ISI) can be " Around the codeword modifier, For this purpose, the output of the channel matching amplifier 33 is transferred to the first input ⑻ of the difference combiner 102, and the second input 103 of the combiner is coupled to receive the post-cursor generated by the evaluation channel impulse response. Represents the echo. The output of the difference combiner 1 02 (representing a "clean" copy of the received codeword) is transferred to the codeword modifier 31, and the output of this modifier is supplied to the codeword decision operator 1 () 5 The codeword decision operator 105 checks all M chip codes in the received codeword instead of a single chip code to make a decision as to which codeword has been transmitted.-It is known that the code obtained by the operator 1G5 Word decision, and then synthesize a copy of the chip code content and the phase information determined by the original transmission codeword in the transmission codeword synthesis benefit 106. The synthesized codeword is then compared with the concealed wave filter within -16 paper sizes. Shicai S 8 standards ⑽S) A4 specification (21 () < 297 公 #) 56171! A7 B7 V. The description of the channel pulse response evaluation implemented in the invention description, in order to be received by the channel matched filter 3 3 Multi-path echo . By supplying this post-cursor echo to the difference combiner 102, the total IS in the output of the channel matching filter 33] [contribution will be effectively canceled from the input to the codeword processor 31. Please note that the channel impulse response evaluation implemented in the FIR filter 107 has no (codeword) length limitation; whether it crosses one or more codeword boundaries, its output covers the signal received by the channel matched filter 3 3 The multi-path echo of the entire post cursor within the signal. In addition, for effective signal processing, the channel matching filter and forward tap section of the DFE can be implemented as a "whitening" matching waver, as shown above. The DFE embedded signal processing architecture used to cancel the internal codeword chip contamination of the energy in the individual codeword c Wi chip code will be described with reference to FIGS. As shown in FIG. 11, the codeword corrector 3 1 of the conventional RAKE receiver has a plurality of individual codeword correctors 3 1 -1 -3 1-N, each of which is used to detect different codeword chip codes. set. The octet field of this example defines a combination of 2 5 6 codewords (including 2-64 coders' each with 22 = 4 possible quadrature phases (0., 900, 180 °, 270 °) ). Each codeword in this example contains eight chip codes, so there are a total of 48 = 64K possible chip code combinations. These 64 codeword chip code combinations can be selected. Using a requirement group previously made based on the properties of the communication application (indoor WLAN) and manufacturing a modifier that reduces complexity, a large number of available chip code combinations can be reduced to codes with only the chip chip set structure according to experience at the beginning. Words, like the Walsh or Hadamard structure described above. Even if this selection criterion can be satisfied from a practical point of view, not all selection groups =
15 561711 五、發明説明( 碼字都會有理想的屬性(尤其是上述的較佳自㈣正與交又 修,屬性),如此即使沒有多路徑式片碼污損’修正器輸出 還是無法展現出理想的脈衝/零特性。尤其其多路徑失真小 於理想片碼集,並且每個片碼都有非常低的嗓訊比,因此 可預期在沒有片碼失真補償形式之下,超過一個以上的碼 子修正之輸出大體上是無法區別的。 若要應付這種片碼污損問題並改善碼字修正的偵測統 計,至本發明每個別瑪字修正器的信號處理分支將設定成 會將組成每一已接收石馬字的所有片碼内容與個別不同組的 碼字伴隨则回授分接之—差異結合在—起,這代表在從 發射經過多4徑頻道傳輸多路徑的特定媽字將經歷過這 後游標多路徑失真回音。一起處理每個已接收碼字的片碼 會增加已接收信號的SNR 6dB,並且可改善每個碼字修正 器刀支的偵測統计精確度。在圖丨2與丨3内圖解顯示從碼字 修正器的修正器輸出上游與下游有效減去或去除後游標多 路徑失真之個別具體實施例。 。在圖12的上游實施中,用於連續接收碼字片碼集(脈衝熱 本訊)的接收化號路徑1 2 0 1將顯示成耦合至複數κ個碼字修 正态統计分支1 2 0 3 · 1、…、1 2 〇 3 - Κ,每個都伴隨個別不 同的Κ種碼字組合之一。如上面說明的,在使用八位元欄位 的本發明範例中,其有Κ> 2 5 6碼字組合(包含26 = 6 4個碼 子’母個都有2 =4種可能的正交相位(〇。、9〇。、180。、 270°)) 〇 每個碼字修正器分支都包含一差異結合器12丨〇、耦合已 18 - 561711 A715 561711 V. Description of the invention (The codeword will have ideal attributes (especially the above-mentioned better self-correction, intersecting and repairing attributes), so that even if there is no multi-path chip code defacement, the output of the modifier cannot be displayed. Ideal pulse / zero characteristics. Especially its multi-path distortion is less than the ideal chip code set, and each chip code has a very low voice ratio, so more than one code can be expected without the chip code distortion compensation form. The output of the sub-correction is generally indistinguishable. To cope with such chip defacement problems and improve the detection statistics of code word correction, the signal processing branch to each Bima word corrector of the present invention will be set to The content of all the chip codes of each received Shima word is accompanied by the code points of the individual different groups. The difference is combined. This represents the specific word of the multi-path transmitted from the transmission through the multi-path channel. Will experience the multi-path distortion echo of the cursor. Processing the chip code of each received codeword together will increase the SNR of the received signal by 6dB, and improve the detection of the knife of each codeword modifier. The accuracy of the calculation is shown in Figures 丨 2 and 丨 3 for the individual specific embodiments of the cursor multipath distortion effectively subtracted or removed from the upstream and downstream of the corrector output of the codeword modifier. In the upstream implementation of FIG. 12 The receiving number path 1 2 0 1 for the continuous reception of codeword chip code sets (pulse hot news) will be displayed as coupled to the complex k number of codeword correction state statistics branches 1 2 0 3 · 1, ..., 1 2 〇3-Κ, each accompanied by an individual different one of the K codeword combinations. As explained above, in the example of the present invention using an octet field, it has K > 2 5 6 codeword combinations ( Contains 26 = 6 4 code children's mothers each have 2 = 4 possible quadrature phases (0., 90., 180., 270 °)) 〇 Each codeword corrector branch contains a differential combination Device 12 丨 〇, coupling has been 18-561711 A7
561711 A7561711 A7
561711 A7 B7561711 A7 B7
五、發明説明L 18 1 J 2 1 - N就要由展開單元1 3 5 0分別展開成複數κ個伴隨2 5 6 種碼字組合(6 4個碼字,每個都是四種可能正交相位(〇。、 90。、180。、270。)之一)的修正器輸出線^^」、、 1 3 5 1 - Κ。展開單元1 3 5 0所定已接收信號路徑碼字修正器 1j20每一 Ν輸出1321-1、·.·、1321-Ν的複合值來識別個 別碼字的四相位旋轉(+ 1、+ j、- 1、- j )。 如個別四組展開輸出線1351-1-135 1-4所示,個別碼字 的四相位旋轉輸出(+ 1、+ j、· 1、- j )會輕合至一組差異結 合?§ 1360_1-1360-4的第一(+ )輸入1361。這些差異結合 器具有耦合來接收來自合成分接路徑並儲存在查找表記憶 體内的複合修正值之第二輸入1362。如同上面說明的,很 明顯地當每個新接收的碼字片碼集要計時至修正器時就必 須重新產生回授分接。差異結合器1360-1-1360_K的輸出 1 3 6 3都耦合至峰值偵測器1 3 8 0,該偵測器會選擇最大的真 實輸出當成實際傳輸碼字。 從上面的說明中明顯得知,藉由在信號處理路徑到接收 器的通道匹配濾波器與碼字修正器上實際上嵌入一決策回 授等化器結構,如此可增強用於在直接序列展頻信號(具有 相當短的碼字長度)上的室内WLAN多路徑應用之傳統 RAKE接收器效能。該決策回授等化器用於消除碼字間兩邊 的中間碼字干擾或「溢出」,以及内碼字晶片干擾(ICI)或 個別碼字片碼内的能量污損。 圖1 4說明圖1 3下游實施更一般的具體實施例。類似於已 接收信號路徑130 1的已接收信號路徑140 1耦合至接收路徑 -21 - 本紙張尺度適用中國國家標準(CNS) A4規格(210 X 297公釐) 裝 訂V. Description of the invention L 18 1 J 2 1-N will be expanded by the expansion unit 1 3 5 0 into a plurality of κ followed by 2 6 6 codeword combinations (6 4 codewords, each of which is four possible positives Cross-phase (0., 90., 180., 270.) modifier output lines ^^ ", 1 3 5 1-Κ. Each unit N of the received signal path codeword corrector 1j20 determined by the expansion unit 1 3 50 outputs a composite value of 1321-1, ..., 1321-N to identify the four-phase rotation (+1, + j, -1,-j). As shown in the individual four sets of unwrapped output lines 1351-1-135 1-4, will the four-phase rotation output (+1, + j, · 1,-j) of individual codewords be lightly combined to a set of difference combinations? § 1360_1-1360-4 The first (+) input is 1361. These differential couplers have a second input 1362 coupled to receive composite correction values from the synthetic tap path and stored in lookup table memory. As explained above, it is clear that the feedback tap must be regenerated when each newly received codeword chip code set is timed to the corrector. The outputs of the differential combiner 1360-1-1360_K 1 3 6 3 are all coupled to the peak detector 1 3 8 0, which will select the largest true output as the actual transmission codeword. It is clear from the above description that by actually embedding a decision feedback equalizer structure on the channel-matched filter and codeword corrector of the signal processing path to the receiver, this can be enhanced for direct sequence development. Performance of traditional RAKE receivers for indoor WLAN multipath applications on high-frequency signals (with fairly short codeword lengths). This decision feedback equalizer is used to eliminate the intermediate codeword interference or "overflow" between the two codewords, as well as the internal codeword chip interference (ICI) or the energy defacement in individual codeword chips. Figure 14 illustrates a more general embodiment of the downstream implementation of Figure 13. Received signal path 140 1 similar to received signal path 130 1 Coupling to receive path -21-This paper size applies Chinese National Standard (CNS) A4 specification (210 X 297 mm) Binding
線 561711 A7Line 561711 A7
五、發明説明(20 ) 字修正器1430將個別FIR濾波器回授分接集丨44〇的輸出與 對應的碼字相比較’並產生對應碼字的評㈣誤信號。該 母一碼子C W -1至C w _ N的評估碼字錯誤信號會提供至對應 的差異結合器1 360之負或相關輸入。差異結合器146〇-ι至 1460-N的輸出都耗合至峰值債測以彻,該制器會以類 似於峰㈣測器138〇的方式選擇最大的真實輸出當成實際 傳輸碼字。 雖然在此已經顯示並說明了 t牛多依照本發明的具體實施 例’吾人可了解到在此並未設限並且精通此技藝的人士還 是可以進行許多改變與修改,吾人並不希望受限在此處所 顯示與說明的細節中,但是希望涵蓋精通此技藝人士所明 瞭的所有類似改變與修正。 ~ 23 - 本紙張尺度適片I中國國家搮準(CNS) A4規格(210 X ^97公釐)V. Description of the Invention (20) The word corrector 1430 compares the output of the individual FIR filter feedback tapping set 4410 with the corresponding codeword 'and generates an evaluation error signal of the corresponding codeword. The evaluation codeword error signals of the mother-to-code children C W -1 to C w _ N are provided to the negative or related inputs of the corresponding difference combiner 1 360. The outputs of the difference combiners 146- to 1460-N are all consumed up to the peak debt measurement. This controller selects the largest true output as the actual transmission codeword in a manner similar to the peak detector 138. Although it has been shown and explained here that according to the specific embodiment of the present invention, we can understand that there are many restrictions and modifications that can be made by those skilled in this art, and we do not want to be limited to The details shown and explained here, but it is intended to cover all similar changes and modifications known to those skilled in the art. ~ 23-This paper is suitable for film I China National Standard (CNS) A4 size (210 X ^ 97 mm)
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US8640009B2 (en) | 2005-03-10 | 2014-01-28 | Qualcomm Incorporated | Methods and apparatus for providing linear erasure codes |
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