1228888 玖、發明說明： 【發明所屬之技術領域】 而詳言之，則與第三代無線 本發明與通信系統有關 通信系統有關。 【先前技術】 現代之無線通信服務須能提供多媒體應用之高速資 傳輸。就第三代無線電通⑽統而言，其目的包括能對個 別使用者提高㈣容量及資料傳輸速率。通常在此類系統 中’由於網路劉覽及標案交換協定（FTP)下載等網際網路通 信之非同步性f，使得基地台至行動台之下載傳輸較上傳 傳輸更形重要。提高無線通道之資料傳輸速率與效率的方 法之一為則編碼技術及多重發射天線。此種方法已於 19=9年11月IEEE期刊第17卷第i84i至！脱頁之通信 專題中’由Foschini等人提出，其論文標題為「使用多^ 兀件陣列之高頻譜效率無線通信之簡化處理」。 、羊而°之’在第二代合夥計劃（3GPP)之寬頻分碼多重1228888 发明 Description of the invention: [Technical field to which the invention belongs] In more detail, it relates to the third generation wireless The present invention relates to a communication system related to a communication system. [Previous Technology] Modern wireless communication services must be able to provide high-speed data transmission for multimedia applications. As far as the third generation radio communication system is concerned, its purpose includes the ability to increase the capacity and data transmission rate for individual users. Usually in such a system, ‘the asynchronous transmission of Internet communications, such as Internet browsing and bidding agreement (FTP) downloads, makes downloading transmissions from base stations to mobile stations more important than uploading transmissions. One of the methods to improve the data transmission rate and efficiency of wireless channels is coding technology and multiple transmitting antennas. This method has been published in IEEE Journal Vol. 17, No. i84i, November 19 = 9! The off-page communication topic was proposed by Foschini et al., And the title of the paper was "Simplified Processing of High-Spectrum-Efficiency Wireless Communication Using Multiple Element Arrays." ， 羊 而 ° 之 ’in the Second Generation Partnership Project (3GPP)
-t，ΜΑ)系統中’係使用通道編碼技術來防止資訊位 兀免又雜訊之破壞。通道編碼技術使用渦輪碼（㈣〇 ode)或迴紅碼，此等編碼方式例如已於哪6年月聰e =刊第^卷第1261至1291頁之通信會刊中，由此職 :”人所提出’其論文標題為「近似最佳化誤差校正編碼及 碼：渴輪瑪」，而且明訂於2 〇 0 2年3月之3 G P P標準：「u E 1228888 ' 射頻發射及接收（FDD)」，TS 25.101 V5.2.0版。3GPP標準 可透過如下網址查閱·· http://WWW.3gpp.org。 另外，為解決通道衰減現象，習知技藝利用發射分集 (transmit diversity)技術，例如多重天線，以使自發射天線 所接收到之信號若為高度衰減時，能夠接收來自另一個發 射天線之更強信號以維持通信。此項習知技藝在3GPP之一 例為時空區塊碼（space-time block code; STBC)，曾於 1998 年10月IEEE期刊第16卷第1451至1458頁的通信專題 中，由Alamouti等人提出，其論文標題為「用於無線通信 之簡易發射分集技術」。 此項習知技藝之另一例為時空籬柵圖碼（space-time trellis-based code)，曾於 1998 年 3 月 IEEE 期刊第 44 卷第 744至765頁的資訊理論會刊中，由Seshadri等人所提出， 其論文標題為「高資料傳輪速率之無線通信的時空碼：性 能標準與編碼結構」。時空籬栅圖碼也許在位元錯誤率（bit error rate; BER)上優於STBC，但此項優點的代價是其編碼 與解碼之複雜程度較高。時空籬柵圖碼為達成較佳之BER 性此’通系採用重複性解碼（iterative decoding)。然而，在 3GPP通信系統中，由於時空籬柵圖碼之編碼技術之複雜解 碼結構之故’若同時用於通道編碼與發射分集，則可能會 產生雙重解碼延遲。因此，時空籬柵圖碼編碼技術可能不 適於做即時之應用。 在3 GPP中已規範並採用兩種時空籬栅圖碼通道編碼 來形成特定之時空編碼方式，此兩種時空籬柵圖通道編碼 1228888 即渦輪碼與迴旋碼。使用渦輪碼與發射分集之時空編碼方 式例如曾於2〇〇1年5月IEEE期刊第19卷第958至968頁 之通信專題中，由Stefanov等人所提出，其論文標題為「具 有發射與接收天線分集之系統在區塊衰減通道上的渦輪編 碼調變：系疵模式、解碼方式與實際考量，以及於2001年 5月IEEE期刊第19卷第969至980頁之通信專題中，由 Liu等人所提出，其論文標題為「全速率時空渦輪碼」。然 而，此等習妒技藝皆著重於效率之增進，而非在於增加 3GPP架構下之資料傳輸速率。 以3GPP標準建構之習知時空編碼方式的範例如圖1 所示。請參聞圖1，分頻雙工（FDD)系統1〇包括一個 專用傳輸通道（DTCH) 12、一個通道解碼器14、一個速率 匹配單元16以及一個STBC編碼器18。DTCH單元12以 每10毫秒（ms)之速率傳送來自上層結構或使用者之3,480 個資訊位元，即速率為3 84 kbps。通道編碼器14連接至 DTCH 12 ’其型式為滿輪編碼器’所提供之渴輪編碼速率 為1/3。通道編碼器14亦透過循環冗餘檢查（crc)之方式來 提供誤差檢測’並且包括十六個CRC填塞（padding)位元與 四個附加（tail)位元。使用於通道編碼器14之渦輪碼為平行 相連之迴旋碼（PCCC)，其具有數個8態成份（8_state constituent)編碼器（圖中未示）。以及一個渦輪碼内交錯器 (internal interleaver)(圖中未示）。PCCC之8態成份碼的轉 換函數如下： G(D)=〔 1，（1+D+D3)/(1+D2+D3)〕 Ι2ί28888 這兩個在一 QPSK符號週期内由天線所同步發射之 QPSK符號在空中相結合，並由接收天線所接收。這兩個空 中相結合之QPSK符號的信號星座圖如圖3B所示。請參閱 圖3B，由於每一 QPSK符號皆映射成丨，^」或」其中之一 個值，兩個相結合之QPSK符號會產生2, l+j，2j，]+j _2 -^j，-2j，l-j或〇其中之一個值，而形成一個具有九個信號 點之星座圖（9-p〇int signal constellation)。 渦輪編碼與發射分集之結合使系統1〇能利用空間與時 間的重複性（redundancy)來改善傳輸效率而不致惡劣化 BER性能。系統1〇以384 kbps傳輸資訊並使用連續 個QPSK符號時間。然而，由於系統1()之傳輸週期或頻寬 以及發射特性、功率等皆已規範於3Gpp標準中，因此若要 經由改變調變方式來增加頻譜效率，勢必也增加系統=雜 【發明内容】 因此，本發明係有關一種無線通信系統及方法，可^ 服因此上述先前技藝之限制或缺點所衍生之諸多問題。 本發明之功效及優點將於下文中描述，且部分之功交 及優點將隨本文之描述或對本發明之實施而更加清楚。^ 發明之目的及其他優點可由下文之描述，中請專利範圍石 圖示之揭露而予以瞭解。 為達成上述目的及優點，本發明提供一種通传系统， 包括-個通道編碼器，用以編碼多個資訊位元；二個映勒 1228888 單元，連接至通道編碼器以將多個資訊位元映射成第一組 正交相位偏移鍵（QPSK)符號與第二組QPSK符號，其中每 預定數目之連續資訊位元係依據一個映射表於一符號期間 内映射成一個第一 QPSK符號與一個第二QPSK符號；一 個第一調變單元，連接至映射單元以將第一 QPSK符號轉 換成一個第一 QPSK星座圖符號；以及一個第二調變單元， 連接至映射單元以將第二QPSK符號轉換成一個第二 QPSK星座圖符號。 在本發明中，通信系統另包括一第一與一第二天線， 分別連接至第一與第二調變單元，用以同步傳輸第一與第 二QPSK星座圖符號。 本發明亦提供一種提高無線通信系統之傳輸速率的方 法，包括提供多個資訊位元；以及將多個資訊位元映射成 第一組正交相位偏移鍵（QPSK)符號與第二組QPSK符號， 其中每預定數目之連續資訊位元係依據一個映射表於一符 號期間内映射成一個第一 QPSK符號與一個第二QPSK符 _ 號。 在本發明中，另包括將第一與第二QPSK符號分別轉 換成一個第一與第二QPSK星座圖符號。 本發明亦提供一種提高無線通信系統之傳輸速率的方 法，包括提供一個第一映射表來建立輸入之二進制位元信 號與正交相位偏移鍵（QPSK)符號間之對應關係，其中每三 個連續之位元係於一符號週期内映射成一個第一 QPSK符 號與一個第二QPSK符號；提供一個第二映射表來建立 11 1228888In the -t, MA) system, channel coding technology is used to prevent the information bits from being damaged by noise. The channel coding technology uses turbo code (㈣ode) or red return code. For example, these coding methods have been used in the communication journal of Satoshi e = vol. ^ Vol. Pp. 1261 to 1291. From this position: " The author's paper titled "Approximately Optimized Error Correction Codes and Codes: Thirty-two Rounds of Mammals", and expressly stated in the March 3, 2002 GPP standard: "u E 1228888 'Radio Frequency Transmission and Reception ( FDD) ", TS 25.101 V5.2.0. The 3GPP standards can be viewed at the following URL: http://WWW.3gpp.org. In addition, in order to solve the channel attenuation phenomenon, the conventional technique uses transmit diversity technology, such as multiple antennas, so that if the signal received from the transmitting antenna is highly attenuated, it can receive stronger signals from another transmitting antenna. Signal to maintain communication. One example of this know-how is space-time block code (STBC) in 3GPP. It was proposed by Alamouti et al. In the communication topic of IEEE Journal Vol.16, pages 1451 to 1458, in October 1998. The title of the paper is "Simple Transmit Diversity Technology for Wireless Communication". Another example of this technique is space-time trellis-based code, which was published in the March 1998 issue of the IEEE Journal of Information Theory, pages 744 to 765, by Seshadri et al. The paper was titled "Space-Time Codes for Wireless Communication with High Data Transfer Rate: Performance Standards and Coding Structure". Spatio-temporal fence pattern codes may be better than STBC in bit error rate (BER), but the price of this advantage is the higher complexity of encoding and decoding. Spatio-temporal fence pattern code is used to achieve better BER performance. It ’s adopted iterative decoding. However, in the 3GPP communication system, due to the complex decoding structure of the space-time fence pattern coding technology, if it is used for both channel coding and transmit diversity, a double decoding delay may occur. Therefore, the space-time fence pattern coding technology may not be suitable for real-time applications. In 3GPP, two types of space-time fence pattern code channel coding have been specified and used to form a specific space-time coding method. These two space-time fence pattern channel codes are 1228888, ie, turbo code and round code. The space-time coding method using turbo code and transmit diversity was proposed by Stefanov et al. In the communication topic of IEEE Journal Vol. 19, pages 958 to 968, May 2001. Modulation of Turbo Coding on a Block Attenuation Channel of a Receive Antenna Diversity System: Defective Modes, Decoding Methods, and Practical Considerations, and in the communications topic of May 2001, IEEE Journal, Volume 19, pages 969-980, by Liu Their paper was titled "Full-rate Space-time Turbo Code". However, these techniques are focused on improving efficiency rather than increasing the data transmission rate under the 3GPP architecture. An example of a conventional spatio-temporal coding method constructed according to the 3GPP standard is shown in Figure 1. Please refer to FIG. 1. A frequency division duplex (FDD) system 10 includes a dedicated transmission channel (DTCH) 12, a channel decoder 14, a rate matching unit 16, and an STBC encoder 18. The DTCH unit 12 transmits 3,480 information bits from the upper structure or the user at a rate of 10 milliseconds (ms), that is, a rate of 3 84 kbps. The channel encoder 14 is connected to the DTCH 12 ', and its type is a full-round encoder', and the thirteen-wheel encoding rate is 1/3. The channel encoder 14 also provides error detection 'by means of a cyclic redundancy check (crc) and includes sixteen CRC padding bits and four tail bits. The turbo code used in the channel encoder 14 is a parallel connected convolutional code (PCCC), which has several 8-state constituent encoders (not shown in the figure). And an internal interleaver (not shown). The conversion function of the 8-state component code of PCCC is as follows: G (D) = [1, (1 + D + D3) / (1 + D2 + D3)] Ι28ί 28888 These two are transmitted synchronously by the antenna within a QPSK symbol period The QPSK symbols are combined in the air and received by the receiving antenna. The signal constellation diagram of the two QPSK symbols combined in space is shown in Figure 3B. Please refer to FIG. 3B, since each QPSK symbol is mapped to one of 丨, ^ "or", two combined QPSK symbols will produce 2, l + j, 2j,] + j _2-^ j,- 2j, lj or 〇 to form a constellation with 9 signal points (9-point signal constellation). The combination of turbo coding and transmit diversity enables the system 10 to take advantage of space and time redundancy to improve transmission efficiency without degrading BER performance. The system 10 transmits information at 384 kbps and uses consecutive QPSK symbol times. However, since the transmission period or bandwidth, transmission characteristics, and power of System 1 () are all specified in the 3Gpp standard, if you want to increase the spectral efficiency by changing the modulation method, it is bound to increase the system = Miscellaneous [Contents of the Invention] Therefore, the present invention relates to a wireless communication system and method, which can overcome many problems arising from the limitations or disadvantages of the foregoing prior art. The functions and advantages of the present invention will be described below, and some of the functions and advantages will become clearer with the description herein or the implementation of the present invention. ^ The purpose of the invention and other advantages can be understood from the description below, which requires the disclosure of the patent scope stone diagram. In order to achieve the above objectives and advantages, the present invention provides a communication system including a channel encoder for encoding multiple information bits; two Yingle 1228888 units connected to the channel encoder to connect multiple information bits Mapped into a first set of quadrature phase shift key (QPSK) symbols and a second set of QPSK symbols, wherein each predetermined number of consecutive information bits are mapped into a first QPSK symbol and a A second QPSK symbol; a first modulation unit connected to the mapping unit to convert the first QPSK symbol into a first QPSK constellation symbol; and a second modulation unit connected to the mapping unit to convert the second QPSK symbol Converted into a second QPSK constellation symbol. In the present invention, the communication system further includes a first and a second antenna connected to the first and second modulation units, respectively, for synchronously transmitting the first and second QPSK constellation symbols. The invention also provides a method for improving the transmission rate of a wireless communication system, which includes providing a plurality of information bits; and mapping the plurality of information bits into a first group of quadrature phase shift key (QPSK) symbols and a second group of QPSK Symbols, wherein each predetermined number of consecutive information bits are mapped into a first QPSK symbol and a second QPSK symbol _ within a symbol period according to a mapping table. In the present invention, it further includes converting the first and second QPSK symbols into a first and second QPSK constellation symbol, respectively. The present invention also provides a method for improving the transmission rate of a wireless communication system, which includes providing a first mapping table to establish a correspondence between an input binary bit signal and a quadrature phase shift key (QPSK) symbol. Consecutive bits are mapped into a first QPSK symbol and a second QPSK symbol in a symbol period; a second mapping table is provided to establish 11 1228888
Qpsk符號與qpSK星座圖符號間之對應關係，其中每一 QPSK符號係映射成一個qPSK星座圖符號，·以及於一符號 週期内同步發射由三個連續之二進制位元信號所形成之兩 個QPSK星座圖符號。 上文對本發明之一般性描述以及下文詳細描述皆為範 例性及说明性質，旨在用以對本發明有進一步之瞭解。 【實施方式】 、X下將芩妝上述圖式對本發明之實施例予以説明。圖 :#同或相似之元件儘可能使用同樣的元件標號來表 不 〇 本發明提供一種使用QPSK虛擬星座圖映像（virtual c〇n^llatlGn mapping; VCM)之通信系統及方法。本發明之 二 '、先及方法改善資料傳輸速率，而不致改變3 架 下傳輸頻寬、傳輸功率或調變方式。 一 QPSK符號由兩個發射天線同步 ’由接收天線所接收到的信號r 通常在3GPP架構下， 發射。就理想通道狀況而言 表示如下： 之二:ΐ實際情況下，所接收到的信號4兩個，Η r"ClXhi + c2Xh2 + n 其中c !及e 2為兩個發射天線所發射之Q P s κ符號 個接收天：Γ通道衰減所影響之雜訊疊加值。當使用-、、泉π，所接收到之信號表示如下·· hi 12 1228888 及h為自發射天線至接收器的路徑增益；而n為相加性白 南斯雜訊（additive white Gaussian noise ; AWGN)。 由於每一個發射之qPSK符號以及以具有ij，」或 -j等四個可能值之一，因此所接收到之信號r為2, 1+』，社 1 +j’ -2, -l-j，_2j，1 -j或〇等九個可能值之一，此九個值亦 即圖3B所示之九信號點星座圖之值。QpsK符號〜及h 由四個資訊位元所組成，例如為圖3A所示之％ 及匕。這四個資訊位元其後形成所接收之信號r，並具有^ 十六個4位元元素所組成之樣本空間。 、 “口之STBC編碼器就兩個qpsk符號之和的觀點來 看，在此-樣本空間中僅有九個狀態或可能值。另外，羽 知之STBC編碼器需要兩個連續的信號^來決定四個輪入1 資訊位元。由於有效之STBC編碼器區塊係形成^ Qpsk符號長度内，因此#STBC編碼器之頻譜效率Correspondence between Qpsk symbols and qpSK constellation symbols, where each QPSK symbol is mapped to a qPSK constellation symbol, and two QPSKs formed by three consecutive binary bit signals are transmitted simultaneously in a symbol period Constellation symbol. The foregoing general description of the present invention and the following detailed description are exemplary and illustrative in nature, and are intended to further understand the present invention. [Embodiment] The embodiment of the present invention will be described with the above drawings under X. Figure: #Same or similar components are represented by the same component numbers as much as possible. The present invention provides a communication system and method using QPSK virtual constellation mapping (VCM). The second method, method and method of the present invention improve the data transmission rate without changing the transmission bandwidth, transmission power, or modulation method under the three shelves. A QPSK symbol is synchronized by two transmitting antennas. The signal r received by the receiving antenna is usually transmitted under the 3GPP architecture. In terms of ideal channel conditions, it is expressed as follows: ΐ In reality, the received signals are two, 两个 r " ClXhi + c2Xh2 + n, where c! And e 2 are the QP s transmitted by the two transmitting antennas. κ symbol receiving days: the noise superimposed value of the Γ channel attenuation. When using-, and π, the received signals are expressed as follows: hi 12 1228888 and h are the path gains from the transmitting antenna to the receiver; and n is the additive white Gaussian noise; AWGN). Since each transmitted qPSK symbol has one of four possible values, such as ij, "or -j, the received signal r is 2, 1+", and the company 1 + j '-2, -lj, _2j One of the nine possible values, such as 1 -j or 0, and these nine values are also the values of the nine signal point constellation diagram shown in FIG. 3B. The QpsK symbols ~ and h are composed of four information bits, such as% and dagger shown in FIG. 3A. These four information bits then form the received signal r and have a sample space consisting of ^ sixteen 4-bit elements. "From the viewpoint of the sum of two qpsk symbols, there are only nine states or possible values in this sample space. In addition, Yu Zhizhi's STBC encoder requires two consecutive signals ^ to determine Four rounds of 1 information bit. Since the effective STBC encoder block is formed within the Qpsk symbol length, the spectral efficiency of the #STBC encoder
Istbc = 4 位元/2 符號週期=2 (bps/Hz)Istbc = 4 bits / 2 symbol period = 2 (bps / Hz)
依據本發明實施例之VCM模型5〇如圖4A VCM模型50完全利用兩個卿符號之和的樣;：二 十六個4位元元素。請參閱4A，VCM模型 曰内 編碼器52於一符號週期内將第一組輪：個VCM Bo、B!、B2映射成一個第一 Q 、°兀，例如 以仏付唬q〇,以及一The VCM model 50 according to the embodiment of the present invention is as shown in FIG. 4A and the VCM model 50 fully utilizes the sum of two symbols;: Twenty-six 4-bit elements. Please refer to 4A, VCM model. The encoder 52 maps the first set of rounds: VCM Bo, B !, B2 into a first Q, ° in a symbol period.
Qpsk符號Ql，，其中第_卿符號。 弟― 出A】，而第二QPSK符號Qi，做為第二於 天線輪Qpsk symbol Ql, where the _qing symbol. Brother-out A], and the second QPSK symbol Qi, as the second to the antenna wheel
符號(3。，與Ql，在空中相結合，並由：輪出A2，SK 四 所接收。每一個QPSK符號Q =(圖中未示、 W白有〇, 1，2, 3等 1228888 可能值之一，其分別對應到實數及虛數部份之丨，。 因此，空中結合之QPSK符號具有2, l+j，2j，_w，’_2 ’ ^ -2j，1 -j等八個可能值之一，形成一個且女 小风個具有八個信號點之星 座圖，如圖4B所示。VCM編碼器52之映射架構與空中相 結合之彳§ 3虎狀悲如下表所列： 輸出之QPSK符號 輸入之二進制 位元 第一天線之 QPSK符號 第二天線之 Qpsk符號 空中相結合 信號狀態 000 0 0 2 001 0 1 1+j 010 1 2 _l+j 011 1 1 2j 100 3 0 Η 101 ---------- 3 3 -2j 110 2 2 -2 111 ---- 1 2 3 -Η 當每三個連續之二進制位元信號饋入VCM編碼器52 時’可得到一個特定之QPSK符號供天線輸出。由於所產 生給每一天線之QPSK符號相同，兩個QPSK符號之和的 1228888 樣本空間便由八個3位元元素所構成。詳言之，此樣本空 間之每一元素皆對應到此3位元之組合的其中之一。因此， 由空中相結合之信號星座圖之觀點，本發明之VCM模型 50充分利用此3位元素來達成編碼效率。與在兩個符號週 期内傳送四個資訊位元之STBC模型相較，VCM模型50 能在一個符號週期内傳送三個位元，亦即在二個符號週期 内能傳送六個位元。VCM模型50之頻譜效率如下： ^Ivcm = 6 位元/2 符號週期=3 (bps/Hz) 因此，無須改變調變方式、傳輸頻寬及傳輸功率，本 發明之VCM模型50之頻譜效率可由2 bps/Hz增加到3 bps/Hz 〇 此外，VCM模型50由接收器之觀點可視為一種 8-QASK(正交振幅偏移鍵）通信系統。在一實施例中，VCM 模型50可應用於圖5所示之3GPP WCDMA通信系統。請 參閱圖5，本發明實施例之通信系統60包括一個專用傳送 通道（DTCH) 62、一個通道編碼器64以及一個VCM編碼器 66。在一實施例中，連接至DTCH 62之通道編碼器64為 速率1/3之渦輪編碼器，以三倍於編碼器輸入之速率來產 生編碼符號。通道編碼器64亦透過循環冗餘檢查（CRC)之 方式來提供誤差檢測，並且包括十六個填塞位元與四個附 力口位元。 VCM編碼器66連接至通道編碼器64，並且提供3 bps/Hz之頻譜效率。通信系統60亦包括連接至VCM編碼 器66之一個第一及第二QPSK調變單元72及74、一個第 15 1228888 一天線82與一個第二天線84。第一與第二天線82、84分 別連接至第一與第二調變單元72、74。第一與第二調變單 元72、74將VCM編碼器之QPSK符號轉換成1、j、-1、 -j四個可能值之一。有了 VCM編碼器66，通信系統60便 能將DTCH單元62之資料傳輸速率由習知STBC系統所能 提供之384 kbps提昇到約450.4 kbps。 現比較如下，假設習知STBC系統在10 ms内傳輸4,524 個QPSK符號，則本發明之系統能在相同之符號速率下提 供改善之資料傳輸效率。由通道編碼器64提供給VCM編* 碼器66之資訊位元數約為13,572 (= 4524X3)。透過編碼器 速率1/3及十六個填塞CRC位元與四個附加位元，由DTCH 通道62每10 ms提供給通道編碼器64之資訊位元數約為 4504 (= 13572/3-16-14)。換言之，通信系統60提供之資料 傳輸速率為450.4 kbps，與習知STBC系統相比較，增加了 17.3%。由於系統之傳輸頻寬、傳輸功率與調變方式都不 變，本發明之VCM模型得以應用於使用多重載波調變之 鲁 3GPP環境，或使用正交分頻多工（OFDM)調變之無線本地 區域網路（LAN)。 本發明因此亦提供一種增加無線通信系統傳輸效率之 方法。此方法包括提供多個資訊位元，以及將此等資訊位 元映射成第一組QPSK符號與第二組QPSK符號。在一實 施例中，係依據一個映射表，在一個符號週期内將每三個 連續之資訊位元映射成第一 QPSK符號與第二QPSK符 號。每一 QPSK符號具有0, 1，2, 3四個狀態之一。接著將 16 1228888 每- QPSK符號轉換成QPSK星座圖符號，其具有n _】， -j四個狀態之一，分別對應至m3之狀態。 ，， 本行人士應可清楚瞭解在本發日狀精神下仍可達成種種不 同之修改或變化。本行人士經由詳讀本說时及實施本發 明’亦可清楚瞭解本發明之其他種種實施例。本說明書及 其中之’施例僅為範例。本發明之範圍及精神由如下申請 專利範圍所界並定。 Μ 【圖式簡單說明】 、本u兒月書中所含之圖式揭示出本發明之實施例，且盘 說明書本文之描述配合讀釋本發日狀目的、優點及原理< 圖1為習知時空編碼方式之方塊圖； 圖2Α與2Β為圖〗所示編碼方式之沙队信號星座圖， 圖3A為圖1之STBC編碼器的等效模型； 圖3B為空中相結合之QpsK符號的信號星座圖； 圖4A為本發明實施例之虛擬星座圖映像； 圖4B為本發明實施例之空中相結合QpsK符號的信號 生座圖；以及 圖5為本發明實施例之通訊系統方塊圖。 10 ·· 3GPP分頻雙工（FDD)系統 14 :通道編碼器 18 : STBC編碼器 12 :專用傳送通道（DTCH) 16 :速率匹配單元 2〇 :天線 1228888 22 ··天線 52 : VCM編碼器 62 :專用傳送通道（DTCH) 66 : VCM編碼器 74 ··第二QPSK調變單元 84 ··第二天線 184 ·· QPSK調變單元 50 : VCM模型 60 :通信系統 64 :通道編碼器 72 ··第一 QPSK調變單元 82 :第一天線 182 ··時空區塊編碼單元 186 : QPSK調變單元 18The symbol (3., combined with Ql, in the air, and received by: turn out A2, SK four. Each QPSK symbol Q = (not shown in the figure, W white has 0, 1, 2, 3, etc. 1228888 may One of the values, which respectively corresponds to the real and imaginary parts. Therefore, the QPSK symbols combined in the air have eight possible values such as 2, l + j, 2j, _w, '_2' ^ -2j, 1 -j, etc. One is to form a female constellation chart with eight signal points, as shown in Figure 4B. The combination of the mapping architecture of VCM encoder 52 and the air 彳 § 3 Tiger-like tragedies are listed in the following table: Binary bit of QPSK symbol input QPSK symbol of first antenna Qpsk symbol of second antenna Air combined signal status 0 0 0 2 001 0 1 1 + j 010 1 2 _l + j 011 1 1 2j 100 3 0 Η 101 ---------- 3 3 -2j 110 2 2 -2 111 ---- 1 2 3 -Η Available when every three consecutive binary bit signals are fed into the VCM encoder 52 A specific QPSK symbol is used for antenna output. Since the QPSK symbols generated for each antenna are the same, the 1228888 sample space of the sum of two QPSK symbols is composed of eight 3-bit elements In detail, each element of this sample space corresponds to one of the three-bit combinations. Therefore, the VCM model 50 of the present invention makes full use of these three from the viewpoint of the signal constellation map combined in the air. Bit element to achieve coding efficiency. Compared with the STBC model that transmits four information bits in two symbol periods, the VCM model 50 can transmit three bits in one symbol period, that is, it can Transmission of six bits. The spectral efficiency of VCM model 50 is as follows: ^ Ivcm = 6 bits / 2 symbol period = 3 (bps / Hz) Therefore, there is no need to change the modulation method, transmission bandwidth, and transmission power. The VCM of the present invention The spectral efficiency of the model 50 can be increased from 2 bps / Hz to 3 bps / Hz. In addition, the VCM model 50 can be regarded as an 8-QASK (quadrature amplitude shift key) communication system from the perspective of the receiver. In one embodiment, The VCM model 50 can be applied to the 3GPP WCDMA communication system shown in FIG. 5. Referring to FIG. 5, the communication system 60 according to the embodiment of the present invention includes a dedicated transmission channel (DTCH) 62, a channel encoder 64, and a VCM encoder 66. In one embodiment, even The channel encoder 64 to DTCH 62 is a turbo encoder with a rate of 1/3, which generates encoding symbols at a rate three times the encoder input. The channel encoder 64 also provides errors through a cyclic redundancy check (CRC) method. Detect and include sixteen stuffing bits and four additional mouth bits. The VCM encoder 66 is connected to the channel encoder 64 and provides a spectral efficiency of 3 bps / Hz. The communication system 60 also includes a first and second QPSK modulation units 72 and 74, a 151228888 antenna 82 and a second antenna 84 connected to the VCM encoder 66. The first and second antennas 82, 84 are connected to the first and second modulation units 72, 74, respectively. The first and second modulation units 72 and 74 convert the QPSK symbol of the VCM encoder into one of four possible values of 1, j, -1, and -j. With the VCM encoder 66, the communication system 60 can increase the data transmission rate of the DTCH unit 62 from the 384 kbps provided by the conventional STBC system to about 450.4 kbps. The comparison is as follows. Assuming that the conventional STBC system transmits 4,524 QPSK symbols in 10 ms, the system of the present invention can provide improved data transmission efficiency at the same symbol rate. The number of bits of information provided by the channel encoder 64 to the VCM encoder * encoder 66 is approximately 13,572 (= 4524X3). Through the encoder rate of 1/3 and sixteen stuffing CRC bits and four additional bits, the number of information bits provided by the DTCH channel 62 to the channel encoder 64 every 10 ms is approximately 4504 (= 13572 / 3-16 -14). In other words, the data transmission rate provided by the communication system 60 is 450.4 kbps, which is an increase of 17.3% compared with the conventional STBC system. Because the system's transmission bandwidth, transmission power, and modulation methods are unchanged, the VCM model of the present invention can be applied to the 3GPP environment using multi-carrier modulation, or wireless using orthogonal frequency division multiplexing (OFDM) modulation. Local area network (LAN). The invention therefore also provides a method for increasing the transmission efficiency of a wireless communication system. The method includes providing a plurality of information bits and mapping the information bits into a first group of QPSK symbols and a second group of QPSK symbols. In one embodiment, every three consecutive information bits are mapped into a first QPSK symbol and a second QPSK symbol in a symbol period according to a mapping table. Each QPSK symbol has one of four states: 0, 1, 2, 3. Then the 16 1228888 per-QPSK symbol is converted into a QPSK constellation symbol, which has one of the four states n_] and -j, respectively corresponding to the state of m3. People in the bank should be able to clearly understand that various modifications or changes can still be achieved under the spirit of this issue. Persons in the Bank can also clearly understand other embodiments of the present invention by reading this explanation and implementing the present invention. This description and the examples thereof are examples. The scope and spirit of the present invention are defined and determined by the following patent applications. Μ [Schematic description] The drawings contained in this book reveal the embodiments of the present invention, and the description in the disc description is combined with the purpose, advantages, and principle of reading the date of the issue < Figure 1 is A block diagram of a known spatio-temporal coding method; Figures 2A and 2B are constellation diagrams of the sand team signal shown in Figure 2; Figure 3A is the equivalent model of the STBC encoder of Figure 1; Figure 3B is the QpsK symbol combined in the air FIG. 4A is a virtual constellation map image according to an embodiment of the present invention; FIG. 4B is a signal generation diagram combining QpsK symbols in the air according to an embodiment of the present invention; and FIG. 5 is a block diagram of a communication system according to an embodiment of the present invention . 10 · 3GPP Frequency Division Duplex (FDD) system 14: Channel encoder 18: STBC encoder 12: Dedicated transmission channel (DTCH) 16: Rate matching unit 20: Antenna 1228888 22 · Antenna 52: VCM encoder 62 : Dedicated transmission channel (DTCH) 66: VCM encoder 74 ·· Second QPSK modulation unit 84 ·· Second antenna 184 ·· QPSK modulation unit 50: VCM model 60: Communication system 64: Channel encoder 72 · The first QPSK modulation unit 82: the first antenna 182The space-time block coding unit 186: the QPSK modulation unit 18