200926670 九、發明說明： 【發明所屬之技術領域】 本發明一般係關於一種傳送裝置、接收裝置、以及在多 載波通信系統中用於重傳之分配子載波的系統及方法，例 如（但並不限於）在正交分頻多工（〇FDM)系統中的自動重複 請求（ARQ)方案。 . 【先前技術】 越來越多的醫院、醫護設施及其他機構正在採用無線區 〇 域網路（WLAN)來提供其行動監視及計算需要以降低成本 並改進病人護理的品質。為了確保經由無線衰減頻道之可 靠傳輸，WLAN(例如在IEEE標準802.1 la中所指定，第11 部分：無線LAN媒體存取控制（MAC)及實體層（PHY)規 格：5GHz頻帶之高速實體層’ 1999年），IEEE802.il η使用 如OFDM及ARQ技術之類技術。OFDM係一技術，其中資 料係（藉由使用個別子載波）透過若干平行子頻道傳送，並 係經由使用基於離散傅立葉轉換（Discrete Fourier W Transform ; DTF)之正交碼並使用一循環首碼來形成。在 文獻中還考量其中使用一預轉換來透過多個子載波擴展該 - 等符號之OFDM變化以提供更高強固性。OFDM及ARQ還 . 係在用於行動通信系統之第三代合夥專案（3GPP)長期演化 (LTE)標準化中所說明的重要技術。 在ARQ中，在一傳輸之後’傳送器或發送器等待來自接 收者的一 ACK(確認）訊息。若資料傳輸失敗，則接著該傳 送器並不接收來自接收器的一 ACK而自動重傳該資料。 134650.doc 200926670 下面說明在一範例性OFDM系統中的一基本ARQ方案。 在一第一傳輸中，資料係透過OFDM子載波來傳送，下 面將稱其為透過原始子載波之原始傳輸。若未接收一 ACK 或若由該傳送器來接收一 NACK，則起始一重傳。此係稱 為ARQ傳輸。該ARQ傳輸發生於一不同組子載波上，下面 將稱其為ARQ子載波。因此，在該等原始子載波上的資料 係重複但係在不同ARQ子載波上，使得每一 ARQ子載波係 與一原始子载波相關聯且該兩個子載波載送相同資料。可 將此一重傳稱為「子載波重複」。該接收器一旦接收來自 兩個傳輸的資料，便使用一特定組合方案（例如最大比率 組合（MRC))來組合該資料以便利用可能藉由該重傳提供之 分集。 用於OFDM系統之傳統ARQ方案已為人所知，例如，可 參見M.Gidlund及P.Ahag的「用於OFDM系統之基於信號分 佈的重新配置及頻率分集之增強HARQ方案（Enhanced HARQ scheme based on rearrangement of signal constellations and frequency diversity for OFDM systems)」（在 2004 年第 59屆IEEE車輛技術會議學報第500及504頁上），或 T.Kumagai等人的用於OFDM信號之一最大比率組合頻率分 集 ARQ方案（A maximal ratio combining frequency diversity ARQ scheme for OFDM signals)」（IEEE PIMRC，第 528至 532頁，1998年），其中已以一預定及固定方式提議AHQ子 载波分配（ARQ-SA)。為利用頻率分集，該ARQ傳輸係在 子載波索引上完成，該等子載波索引係相對於該等原始子 134650.doc 200926670 載波索引而由一固定數字循環偏移。雖然此等方法並不具 有任何額外發信負擔，但由於其並不利用頻道狀態資訊， 故即使結合ARQ之性能改進亦可能受到限制。若在經歷深 度衰減的子載波上傳送之資料係在一組仍經歷深度衰減的 子載波上再次重傳，則尤其如此。在此等條件下，重傳導 . 致輸出明顯減少而並不提供任何顯著的性能改進。 , W〇_2G()5()78976A1揭示—重傳系統，其中在先前失敗的 肖包中藉由子載波載送之資料係在不同子載波上重傳。該 罾 &前接收的失敗資料係與用於❹j之重傳組合…完整頻 道品質指示器（CQI)之一子集係用於決定最佳品質子載 波，接|將該最佳品質子載波分配用於已失敗過多次的一 封包之-重傳。但是，在由一使用者使用所有子載波的系 統中，此子載波分配並不適用，因為所有子載波失敗相同 的次數（例如，在該第一重傳中有一次）。 【發明内容】 ❹ 纟發月t目的係提供"'種用於重傳之更靈活的子載波 分配，其還可用於其中可由一使用者使用所有子載波之重200926670 IX. Description of the Invention: [Technical Field] The present invention generally relates to a transmitting apparatus, a receiving apparatus, and a system and method for allocating subcarriers for retransmission in a multi-carrier communication system, for example (but not Limited to the Automatic Repeat Request (ARQ) scheme in Orthogonal Frequency Division Multiplexing (〇FDM) systems. [Prior Art] More and more hospitals, healthcare facilities, and other organizations are using wireless local area networks (WLANs) to provide their mobile surveillance and computing needs to reduce costs and improve the quality of patient care. To ensure reliable transmission over wirelessly attenuated channels, WLAN (eg as specified in IEEE Standard 802.1 la, Part 11: Wireless LAN Media Access Control (MAC) and Physical Layer (PHY) Specifications: High Speed Physical Layer of the 5 GHz Band' 1999), IEEE 802.il η uses technologies such as OFDM and ARQ technologies. OFDM is a technique in which data is transmitted through several parallel subchannels by using individual subcarriers, and by using a Discrete Fourier W Transform (DTF) based orthogonal code and using a cyclic first code. form. It is also contemplated in the literature that a pre-conversion is used to extend the OFDM variation of the - symbol over a plurality of subcarriers to provide higher robustness. OFDM and ARQ are also important technologies described in the Third Generation Partnership Project (3GPP) Long Term Evolution (LTE) standardization for mobile communication systems. In ARQ, the transmitter or transmitter waits for an ACK (acknowledgement) message from the receiver after a transmission. If the data transmission fails, then the transmitter does not receive an ACK from the receiver and automatically retransmits the data. 134650.doc 200926670 A basic ARQ scheme in an exemplary OFDM system is described below. In a first transmission, the data is transmitted over the OFDM subcarriers, which will be referred to as the original transmission through the original subcarriers. If an ACK is not received or if a NACK is received by the transmitter, a retransmission is initiated. This is called ARQ transmission. The ARQ transmission occurs on a different set of subcarriers, which will be referred to below as ARQ subcarriers. Thus, the data on the original subcarriers is repeated but on different ARQ subcarriers such that each ARQ subcarrier is associated with an original subcarrier and the two subcarriers carry the same data. This retransmission can be referred to as "subcarrier repetition." Once the receiver receives the data from the two transmissions, it combines the data using a particular combination scheme (e.g., Maximum Ratio Combination (MRC)) to take advantage of the diversity that may be provided by the retransmission. Conventional ARQ schemes for OFDM systems are known, for example, see M. Gidlund and P. Ahag, "Enhanced HARQ scheme based on signal distribution based reconfiguration and frequency diversity for OFDM systems." On rearrangement of signal constellations and frequency diversity for OFDM systems)" (on pages 500 and 504 of the 59th IEEE Conference on Vehicle Technology, 2004), or one of the maximum ratio combining frequencies for OFDM signals by T. Kumagai et al. A maximal ratio combining frequency combining ARQ scheme for OFDM signals (IEEE PIMRC, pp. 528-532, 1998), in which AHQ subcarrier allocation (ARQ-SA) has been proposed in a predetermined and fixed manner. To utilize frequency diversity, the ARQ transmission is done on a subcarrier index that is offset by a fixed number of cycles relative to the original 134650.doc 200926670 carrier index. Although these methods do not have any additional signaling burden, they may be limited even if they do not utilize channel status information, even if combined with ARQ performance improvements. This is especially true if the data transmitted on sub-carriers experiencing deep attenuation is retransmitted on a set of sub-carriers that still experience deep attenuation. Under these conditions, re-conduction results in a significant reduction in output without providing any significant performance improvement. , W〇_2G() 5() 78976A1 discloses a retransmission system in which data carried by subcarriers in previously failed packets is retransmitted on different subcarriers. The 接收& pre-received failure data is combined with the retransmission for ❹j... a subset of the complete channel quality indicator (CQI) is used to determine the best quality subcarrier, and the best quality subcarrier is Assign a retransmission to a packet that has failed multiple times. However, in systems where all users use all subcarriers, this subcarrier allocation is not applicable because all subcarriers fail the same number of times (e.g., once in the first retransmission). SUMMARY OF THE INVENTION The purpose of the present invention is to provide a more flexible subcarrier allocation for retransmission, which can also be used in which all subcarriers can be used by a user.
傳系統D 此目的係藉由如請求们之傳送裝置、如請求項i5之接 «置’以及如請求項31之方法來達到。該方法可以係實 施為—可安裝並可在-電腦器件上運行之軟體常式。 據此’提出透過重傳子載波之—f料重傳，其中重傳子 載^系與該等原始子載波適當組合以便最佳化一所需系統 衡里（例如最大化該最小子載波信號對雜訊比⑽⑼。應 134650.doc 200926670 注意在無線系統（例如，IEEE 802· 11 η、3GPP LTE)中，正 越來越多地考量閉路回授方法，其中接收器將（例如）一頻 道狀態資訊CSI(在一些標準中亦稱為頻道品質指示器 (CQI))回授給該傳送裝置。此或者其他頻道或傳輸品質資 訊可用於設計該重傳以便充分利用頻域中提供的分集。因 此，與傳統技術相比可明顯改進系統性能。由於建議使用 完整傳輸品質資訊（例如CQI)，因此可提供一不同的匸以感 知重新分配方案。更明確言之，分配或配置用於重傳之該 等子載波以改進後續封包恢復之可靠性，其中評估所有可 用品質資訊以決定一改進的子載波重新分配，該改進的子 載波重新分配可以係轉換成更高輸出、更低錯誤機率、更 高服務品質等。 如上所述’該傳輸品質資訊可以係從該CSI或該CQJ導 出。由於此類資訊可用於當前系統中，故促進所提議重傳 方案的實施。 . 此外，該第一組原始子載波及該第二組重傳子載波可包 含相同數目的子載波9此可選特徵可減少該所提議子載波 分配所需的處理步驟。 在一第一態樣中，可在傳送器側或在接收器側提供之重 傳控制單元可經調適成藉由將具有最高傳輸品質且尚未分 配之重傳子載波迭代分配給具有最小有效傳輸品質之原始 子載波來執行子載波分配，且其中有效傳輸品質係藉由將 該所分配之重傳子載波之傳輸品質與該所分配之重傳子載 波已分配給的該原始子載波之傳輸品質相加來獲得。此多 134650.doc 200926670 個子載波分配導致一最佳化分配，其中可對重傳子載波進 行多次分配以提焉整體效率。 在一第二態樣中，可在傳送器側或在接收器側提供之重 傳控制單元可經調適成將該第二組之至多一個重傳子載波 分配給該第一組之每一原始子載波。因此，可達到一對一 或單一子載波分配，其中每一重傳子載波係僅使用一次。 • 更明確言之，在該第二態樣中，該重傳控制單元可經調 適成藉由將具有最高傳輸品質且尚未分配之重傳子載波迭 代分配給具有最小有效傳輸品f且尚未分配之原始子載波 來執灯子載波分配，且其中該有效傳輸品質係藉由將該所 刀配之重傳子載波之傳輸品質與該所分配之重傳子載波已 分配給的該原始子載波之傳輸品質相加來獲得。 在亦係關於-單一子載波分配的情況之一第三態樣中， 可在該傳送器側或在該接收器側提供之重傳控制單元可經 調適成藉由對該第-組之原始子載波從最小至最大傳輸品 〇 #進行分類’藉由以—相反方式對該第二組之重傳子載波 從最小至最大傳輸品質進行分類以及藉由將第_最強重 傳子載波分配給第11個最弱原始子載波來執行子載波之分 配。因此，該分配可以係藉由一具有更少處理步驟之較簡 單演算法來達成。 若該第二組重傳子載波係大於該第-㈣始子載波，則 該重傳控制單元可經調適成再次分配剩餘的重傳子載波， 例如符合依據該第三態樣之上述分配方案。 若在該傳送器側提供該重傳控制單元，則其可經調適成 134650.doc 200926670 接收來自接收端之一回授資訊。可以（例如）一否定接收確 認或NACK來接收該回授資訊。該回授資訊可以係（例如） 一分配資訊’其中該重傳控制單元經調適成基於該分配資 訊來執行子載波分配。 作為一替代選項，該回授資訊可包含該傳輸品質資訊， 其中該重傳控制早元可經調適成基於該回授資訊比較該等 原始子载波與該等重傳子載波之雜訊比，基於所比較的雜 訊比來執行子載波分配，以及將該子載波分配之結果前饋 給該重傳之接收端。 其他有利發展係定義在隨附申請專利範圍中。 【實施方式】 下面基於圖1及2示意性繪示之一範例性〇1?]〇]^系統說明 較佳具體實施例。但是，亦可考量基於正交編碼傳輸之任 何其他系統。 在一 OFDM傳輸系統之一傳送器處，調變符號之一區塊 係經由一反向離散傅立葉轉換來傳遞，其通常係使用該反 向快速傅立葉轉換（IFFT)來實施。在插入具有不短於最大 頻道延遲擴展之持續時間的一循環首碼以避免内部OFDM 符號間的干擾之後，藉由使用M1個原始子載波來傳送一 OFDM符號。在接收器處，移除對應於該循環首碼之所接 收k號之樣本。在施加一快速傅立葉轉換（FFT)之後，在 頻域中獲得一所接收子載波向量。 當一原始傳輸失敗時，發送在每一 〇FDM符號中由賊2個 ARQ子載波組成之一重傳（其還可稱為一 arq傳輸）^若 134650.doc -11 · 200926670 M1=M2，則所有原始子載波係用於傳送資料。原則上， M2可不同於Ml ’因此允許在該ARQ傳輸中使用—可 的冗餘m之，若M1>M2，則採用—遞增冗餘 的M1-M2個子載波可用於傳賴資料或係配置給在一、 用者系統中的其他使用者。 > 圖1顯示依據該第一具體實施例之一〇FDM重傳系統之— 不思性方塊圖’其中將一傳給品暫咨^ 得翰印質資讯回授給一傳輪器件 ❹ 參 1〇並在該傳輸器件_執行子載波分配。圖！之上部部分係 關於原始傳輸’而圖丨之下部部分係關於arq傳輸或重 傳。因此，圖1還涉及一時間相關尺度。更明確言之，告 要求一重傳時’起始藉由子載波重複之-ARQ，並在提： 於-接收器件20處之-組合器22〇處組合該等所接收的原 始與ARQ子載波。 μ 在原始傳輸（圖i之上方部分）中，經由其中應用贿之 一傳送器U〇透過編號為卜2、…、〜的子載波(SC)傳送一 平行資料串流dI、d2、."、dMe但是在arq傳輸（圖】之下 部部分）中，該平行資料串流H...、dM係透過編號 為kl、k2、...、kM的子載波傳送，其中u、k2、 係1、2、..·、M之一置換。在其中應用FFT之-接收器210 處接收時，在編號為Mkl(等）的子載波上之資料係經由該 組合器220來處理’例如’藉由使用一最大比率組合 (MRC)。但是’亦可使用任何其他組合方案。 在=第一具體實施例中，經由一對應回授機構30(例 月』導頻道、回授控制頻道或類似者）將一傳輸或頻道 134650.doc -12- 200926670 品質資訊（例如，CSI、CQI或類似者））回授給一子載波分 配單元120，該子載波分配單元120係在傳輸器件1〇處提供 並經調適成計算、決定或推導該等重傳或ARq子載波與該 等原始子載波之間的分配，即，可轉遞給接收器件2〇之用 於kl、k2、…、kM之分配。因此，在該第一具體實施例 ' 中’該接收器件20回授該品質資訊，且該傳輸器件1〇決定 " 子載波分配。接著所得分配資訊可以係與該ARQ傳輸一起 前饋而使得該接收器件20可正確處理該ARQ傳輸及該原始 ❹ 傳輸。 圖2顯示依據第二具體實施例之一 0Fdm重傳系統之一示 意性方塊圖’其中將一子載波分配從接收器件2〇回授給傳 輸器件10且在該接收器件20處提供的一分配單元230中執 行子載波分配。類似於圖1 ’圖2之上部部分係關於原始傳 輸，而圖2之下部部分係關於ARQ傳輸或重傳。 與圖1具有相同參考數字之圖2之該些部分採用一類似方 φ 式進行操作，因此為清楚及簡化起見並不再次說明。 在該第二具體實施例中，一傳輸或頻道品質資訊（例 如’ CSI、CQI或類似者）係在該接收器件2〇處獲得（例如測 量）或接收（例如發信給該接收器件20)並係供應至一子載波 * 分配單元230 ’該子載波分配單元230係在該接收器件2〇處 提供並經調適成計算、決定或推導該等重傳或ARq子載波 與該等原始子載波之間的分配，即用於k 1、k2、…、kM的 分配。指示該子載波分配之一資訊係經由對應回授機構 3〇(例如，前導頻道 '回授控制頻道或類似者）回授給該傳 134650.doc -13· 200926670 送器件ίο以應用用於一重傳之子載波分配β因此，在該第 二具體實施例中，接收器件20基於該品質資訊決定該子載 波分配並將該子載波分配回授給該傳輸器件丨〇。 對於一準靜態頻道，用於該等原始子載波與該等arq子 載波兩者之子載波SNR係在接收器件2〇處已知，且可用於 決定ARQ-SA並將其回授給傳輸器件1〇0實際上，對於一 快速ARQ回應，所計算的ARQ-SA可以係背負一傳統上用 於請求該ARQ傳輸的NACK(或其他否定傳輸確認或重傳請 求）。The transmission system D is achieved by means of a transmitting device such as a requester, such as the request «i" and the method of claim 31. The method can be implemented as a software routine that can be installed and run on a computer device. Accordingly, a retransmission of subcarriers is proposed, wherein retransmission subcarriers are properly combined with the original subcarriers to optimize a desired system balance (eg, maximizing the minimum subcarrier signal) For noise ratio (10)(9). Should be 134650.doc 200926670 Note that in wireless systems (eg, IEEE 802.11, 3GPP LTE), closed loop feedback methods are increasingly being considered, where the receiver will, for example, a channel Status information CSI (also referred to as channel quality indicator (CQI) in some standards) is fed back to the transmitting device. This or other channel or transmission quality information can be used to design the retransmission to take advantage of the diversity provided in the frequency domain. As a result, system performance can be significantly improved compared to traditional techniques. Since full transmission quality information (such as CQI) is recommended, a different trick can be provided to perceive the redistribution scheme. More specifically, allocation or configuration for retransmission The subcarriers are used to improve the reliability of subsequent packet recovery, wherein all available quality information is evaluated to determine an improved subcarrier reassignment, the improved subcarrier re The allocation can be converted to higher output, lower error probability, higher service quality, etc. As mentioned above, the transmission quality information can be derived from the CSI or the CQJ. Since such information can be used in the current system, it is promoted. Implementation of the proposed retransmission scheme. Furthermore, the first set of original subcarriers and the second set of retransmission subcarriers may comprise the same number of subcarriers 9 this optional feature may reduce the required subcarrier allocation required Processing step. In a first aspect, the retransmission control unit, which may be provided on the transmitter side or at the receiver side, may be adapted to iteratively assign by having the highest transmission quality and unallocated retransmission subcarriers to have The original subcarrier of the minimum effective transmission quality is used to perform subcarrier allocation, and wherein the effective transmission quality is obtained by assigning the transmission quality of the allocated retransmission subcarrier to the original subtitle to which the allocated retransmission subcarrier has been allocated The transmission quality of the carrier is added to obtain. This multiple 134650.doc 200926670 subcarrier allocation results in an optimized allocation, in which the retransmission subcarrier can be allocated multiple times to Overall efficiency. In a second aspect, the retransmission control unit, which may be provided on the transmitter side or on the receiver side, may be adapted to assign at most one retransmission subcarrier of the second group to the first group. Each original subcarrier. Therefore, one-to-one or single subcarrier allocation can be achieved, wherein each retransmission subcarrier is used only once. • More specifically, in the second aspect, the retransmission control unit can Adapted to perform subcarrier allocation by assigning the retransmission subcarrier with the highest transmission quality and not yet allocated to the original subcarrier having the least significant transmission f and not yet allocated, and wherein the effective transmission quality is Obtaining, by adding the transmission quality of the retransmitted subcarrier of the knife to the transmission quality of the original subcarrier to which the allocated retransmission subcarrier has been allocated. In a third aspect, also in the case of a single subcarrier allocation, the retransmission control unit available on the transmitter side or on the receiver side may be adapted to be original by the first group The subcarriers are classified from the minimum to the maximum transmission quality 〇# by classifying the second group of retransmission subcarriers from the smallest to the maximum transmission quality in the opposite manner and by assigning the _th strongest retransmission subcarrier to The eleventh weakest original subcarrier is used to perform allocation of subcarriers. Therefore, the allocation can be achieved by a simpler algorithm with fewer processing steps. If the second group of retransmission subcarriers is greater than the first (fourth) initial subcarrier, the retransmission control unit may be adapted to allocate the remaining retransmission subcarriers again, for example, according to the foregoing allocation scheme according to the third aspect. . If the retransmission control unit is provided on the transmitter side, it can be adapted to receive feedback information from one of the receiving ends 134650.doc 200926670. The feedback information can be received, for example, by a negative acknowledgement or NACK. The feedback information may be, for example, an allocation information 'where the retransmission control unit is adapted to perform subcarrier allocation based on the allocation information. As an alternative, the feedback information may include the transmission quality information, wherein the retransmission control early element may be adapted to compare a noise ratio of the original subcarriers to the retransmitted subcarriers based on the feedback information. The subcarrier allocation is performed based on the compared noise ratio, and the result of the subcarrier allocation is fed forward to the receiving end of the retransmission. Other advantageous developments are defined in the scope of the accompanying patent application. [Embodiment] Hereinafter, a preferred embodiment will be described based on an exemplary embodiment of the present invention based on FIGS. 1 and 2. However, any other system based on orthogonal code transmission can also be considered. At one of the OFDM transmission systems, one of the modulated symbols is passed via an inverse discrete Fourier transform, which is typically implemented using the inverse fast Fourier transform (IFFT). After inserting a cyclic first code having a duration not shorter than the maximum channel delay spread to avoid interference between internal OFDM symbols, an OFDM symbol is transmitted by using M1 original subcarriers. At the receiver, the sample corresponding to the received k number of the first code of the loop is removed. After applying a fast Fourier transform (FFT), a received subcarrier vector is obtained in the frequency domain. When an original transmission fails, the transmission is retransmitted in one 〇 FDM symbol by one of the thief 2 ARQ subcarriers (which may also be referred to as an arq transmission). ^ If 134650.doc -11 · 200926670 M1=M2, then All original subcarriers are used to transmit data. In principle, M2 can be different from M1 'so allows for the use of - redundant redundancy in the ARQ transmission, if M1 > M2, then - incrementally redundant M1-M2 subcarriers can be used for the data or configuration To other users in the user system. > Fig. 1 shows an inconspicuous block diagram of a FDM retransmission system according to one of the first specific embodiments, in which a sub-consultation is sent back to a transmission device. The subcarrier allocation is performed in the transmission device_. Figure! The upper part is about the original transmission' and the lower part of the picture is about arq transmission or retransmission. Therefore, Figure 1 also relates to a time correlation scale. More specifically, a retransmission "restart" is performed by subcarrier repetition - ARQ, and the received original and ARQ subcarriers are combined at the combiner 22 at the receiving device 20. μ In the original transmission (the upper part of Fig. i), a parallel data stream dI, d2, ." is transmitted via the subcarrier (SC) numbered Bu 2, ..., ~ via the application of the bribe transmitter U. ;, dMe but in the arq transmission (lower part of the figure), the parallel data stream H..., dM is transmitted through subcarriers numbered kl, k2, ..., kM, where u, k2 One of the 1, 2, .., and M substitutions. When receiving at the receiver FFT where the FFT is applied, the data on the subcarriers numbered Mkl (etc.) is processed via the combiner 220 'e.g. by using a maximum ratio combination (MRC). However, any other combination scheme can be used. In the first embodiment, a transmission or channel 134650.doc -12-200926670 quality information (eg, CSI, via a corresponding feedback mechanism 30 (monthly channel, feedback control channel, or the like)) CQI or the like) is fed back to a subcarrier allocation unit 120, which is provided at the transmission device 1 and adapted to calculate, decide or derive the retransmission or ARq subcarriers and the like The allocation between the original subcarriers, that is, the allocation for the receiving device 2 for kl, k2, ..., kM. Therefore, the receiving device 20 returns the quality information in the first embodiment ', and the transmitting device determines the "subcarrier allocation. The resulting allocation information can then be fed forward with the ARQ transmission such that the receiving device 20 can properly process the ARQ transmission and the original transmission. 2 shows a schematic block diagram of an OFDM retransmission system according to a second embodiment, wherein a subcarrier allocation is fed back from the receiving device 2 to the transmission device 10 and an allocation is provided at the receiving device 20. Subcarrier allocation is performed in unit 230. Similar to Fig. 1 'the upper part of Fig. 2 relates to the original transmission, and the lower part of Fig. 2 relates to the ARQ transmission or retransmission. The portions of Fig. 2 having the same reference numerals as in Fig. 1 are operated in a similar manner, and therefore will not be described again for the sake of clarity and simplification. In the second embodiment, a transmission or channel quality information (eg, 'CSI, CQI, or the like) is obtained (eg, measured) or received (eg, sent to the receiving device 20) at the receiving device 2A. And is supplied to a subcarrier* allocation unit 230. The subcarrier allocation unit 230 is provided at the receiving device 2〇 and adapted to calculate, determine or derive the retransmission or ARq subcarriers and the original subcarriers. The assignment between, ie for the allocation of k 1, k2, ..., kM. Information indicating that the subcarrier allocation is sent back to the transmission via the corresponding feedback mechanism 3 (for example, the preamble channel 'receiving control channel or the like) to the transmission 134650.doc -13·200926670 to send the device ίο to apply for one weight Subcarrier allocation β. Therefore, in the second embodiment, the receiving device 20 determines the subcarrier allocation based on the quality information and assigns the subcarrier back to the transmitting device. For a quasi-static channel, the subcarrier SNR for both the original subcarrier and the arq subcarriers is known at the receiving device 2, and can be used to determine the ARQ-SA and feed it back to the transmitting device 1实际上0 In fact, for a fast ARQ response, the calculated ARQ-SA may carry a NACK (or other negative transmission acknowledgement or retransmission request) that is traditionally used to request the ARQ transmission.
圖1及2皆係關於一所謂的單一 ARQ子载波分配（arq· SA)方法，其中至多一個ARQ子載波可以係分配至每一原 始子載波。在原始傳輸中，該平行資料串流dl、d2、…、 dM係透過編號為1、2、…、Μ的子載波傳送。但是在ARQ 傳輸中，該平行資料串流dl、d2、…、dM係透過編號為 kl、k2、…、kM的子載波傳送，其中kl、k2、、…係 1、2、…、Μ之一置換。 在該等上述第一及第二具體實施例中，可考量之一成本 函數係在子載波組合於該組合器22〇中之後將最小snr最 大化。但是，所提議之子載波分配一般適用於各種其他類 型的成本函數。此外，一般而言，原始及ARQ子載波之兩 個個別數目Μ1及M2可以係不同的。 此外，重傳之數目並不一定為一，即資料係經由一個 ARQ傳輸成功地恢復。所提議之子载波分配一般亦適用於 需要多個ARQ傳輸之情況，其中因此針對該多個傳輸應用 134650.doc •14- 200926670 在組合器220處的組合處理。此外，該頻道可以或可以不 隨著OFDM符號而變化。 下面說明用於推導kl、k2、...、kM之一（最佳）選擇 (即，用於重傳之子載波分配）之方法或演算法以及用於保 持低回授負擔之若干額外技術。假設原始子載波之數目為 抓且用於標記該等子載波之索引為W=1、2、、抓。此 * 外，假設ARQ子载波之數目為M2且用於標記該等ARQ子載 波之索弓丨為、2、…、Λ/:。 ϋ 作為一範例，該等原始子載波及該等ARQ之子載波之 CSI可用於ARQ_SA。CSI，其可作為該等子載波之信號對 雜訊比（SNR)。從CSI中已知該等原始子載波之SNR且其係 表不為，W=1、…、抓。此外，從CSI中已知該等ARQ 子載波之SNR且其係表示為火，„=1、.、此。Figures 1 and 2 relate to a so-called single ARQ subcarrier allocation (arq·SA) method in which at most one ARQ subcarrier can be allocated to each original subcarrier. In the original transmission, the parallel data streams dl, d2, ..., dM are transmitted through subcarriers numbered 1, 2, ..., Μ. However, in the ARQ transmission, the parallel data streams dl, d2, ..., dM are transmitted through subcarriers numbered kl, k2, ..., kM, where kl, k2, ... are 1, 2, ..., Μ A replacement. In the first and second embodiments described above, one of the cost functions can be considered to maximize the minimum snr after the subcarriers are combined in the combiner 22A. However, the proposed subcarrier allocation is generally applicable to various other types of cost functions. Moreover, in general, the two individual numbers 原始1 and M2 of the original and ARQ subcarriers may be different. In addition, the number of retransmissions is not necessarily one, that is, the data is successfully recovered via an ARQ transmission. The proposed subcarrier allocation is also generally applicable to situations where multiple ARQ transmissions are required, where the combined processing at combiner 220 is therefore applied for the multiple transmissions 134650.doc • 14- 200926670. Moreover, the channel may or may not vary with OFDM symbols. The following describes a method or algorithm for deriving one (best) selection of kl, k2, ..., kM (i.e., subcarrier allocation for retransmission) and several additional techniques for maintaining a low feedback burden. It is assumed that the number of original subcarriers is grab and the index used to mark the subcarriers is W=1, 2, and grab. In addition to this, it is assumed that the number of ARQ subcarriers is M2 and is used to mark the ARQ subcarriers as 2, ..., Λ/:. ϋ As an example, the CSIs of the original subcarriers and the subcarriers of the ARQs can be used for ARQ_SA. CSI, which acts as a signal-to-noise ratio (SNR) for these subcarriers. The SNRs of the original subcarriers are known from the CSI and their coefficients are not, W = 1, ..., grab. Furthermore, the SNR of the ARQ subcarriers is known from the CSI and is expressed as fire, „=1, .
若在組合器220中使用MRC且若第《個ARQ子载波係用於 重複藉由第m個原始子載波所載送之信號，則因此將原始 ❿ 子載波之有效SNR增加至火。此處定義該有效SNR 因其將在以後說明之子載波分配中使用。 現說明兩個通用子載波分配方案，即，單一 A及 •多個ARQ-SA，並參考圊3至7藉由簡單範例來解說。該等 兩個方案在藉以將該等ARQ子載波分配給該等原始子載波 的方法上不同。 假设形式為原始及arq子載波之snr的CSI係已知。可 在該頻道係互反時或藉由一明確的CSI回授，在傳輸器件 10處估計該CSI，該明確的CSI回授係用於長期川演化系 134650.doc !5 200926670 統（LTE)中，例如，如3GPP之對演化的UTRA(E-UTRA)及 演化的UTRAN(E-UTRAN)之要求（標準技術報告25.913)中 所述。因此，只要在頻道同調時間内較佳地發送該ARQ子 載波，便可將依據子載波SNR之CSI視為實務上已知。 對於最高性能增益，顯然可使用所有ARQ子載波。另 外，為了直接採用MRC，不應將一 ARQ子載波分配至兩個 或更多原始子載波。否則，將需要諸如干擾抑制或消除之 類更先進的信號處理技術。 為了致使有效並簡單的接收器處理，在所有提議分配方 案中，應將每一 ARQ子載波分配給恰好一個原始子載波。 但是，此點並非一本質上要求。無論取決將一個ARQ子載 波分配給一原始子載波或係將多個ARQ子載波分配給一原 始子載波，該兩個ARQ-SA方案係可行。 圖3顯示一多個ARQ-SA方案之一流程圖，其中將ARQ子 載波以一個接一個子載波的方式迭代分配給該等原始子載 波。對於初始化，在步驟S 1中，該有效SNR係設定為該等 原始子載波之SNR。接著在每一迭代中，將至此尚未分配 之最強的ARQ子載波分配給具有最小有效SNR之原始子載 波（步驟S2)。在每一分配之後，更新該有效SNR。最後， 所分配之重傳子載波可用於重傳有關資料（步驟S3)。 因此，在所提議的多個ARQ-SA方案中，可將多個ARQ 子載波分配給每一原始子載波，即，在每一分配迭代中， 將具有最大SNR且尚未分配之ARQ子載波分配給至此具有 最小有效SNR之原始子載波。 134650.doc -16- 200926670 圖4顯示其中兩次使用一 ARQ子載波之一範例之一圖 解。於此範例中，假定： ai = l，o：2==5，a3 = l〇，jLp1=3，y92=2，^3=l°(gp，Ml=M2:=3。） 最初在任何分配之前，原始子載波之有效SNR，〜僅係 其原始SNR，，其意味著： 迭代 〇 : yi = l，y2=5，y3=l〇。 現將具有最大SNR且尚未分配之ARQ子載波（即W分配 給至此具有最小有效SNR之原始子載波（即，其意味 著： 迭代 1 . )^=4，y2 = 5，y3=l〇。 再次’將具有最大SNR且尚未分配之ARQ子載波（即彡2) 分配給至此具有最小有效SNR之原始子載波（即yi)，其意 味著： 迭代 2 . ’ 72=5，y3 = l〇。 最後，將具有最大SNR且尚未分配之ARQ子載波（即夕3) 分配給至此具有最小有效SNR之原始子載波（即y2) ’其意 味著： 迭代 3 . ，y2=6，y3 = l〇。 由於所有ARQ子載波係用盡，故結束該子載波分配。從 圖4推斷，該等第一及第二ARQ子載波係用於重複該第一 原始子載波，而該第三ARQ子載波係用於重複該第二子載 圖5顯示一單一 ARQ-SA方案之一流程圖，其中將至多一 個ARQ子載波分配給每一原始子載波。此舉減少可能分配 134650.doc -17· 200926670 之數目。 對於初始化，在步驟S1中，該有效SNR係再次設定為該 等原始子載波之SNR。接著在每一迭代中，將至此尚未分 配之最強的ARQ子載波分配給至此具有最小有效snr且尚 未分配之原始子載波（步驟S2)。在每一分配之後，更新該 有效SNR。最後’所分配之重傳子載波可用於重傳有關資 料（步驟S3)。 因此，在每一分配迭代中，將具有最大SNR且尚未分配 之ARQ子載波分配給至此具有最小有效snr且尚未分配之 原始子載波。 圖6顯示其中每一ARQ子载波僅使用一次之一範例之一 解說。於此範例中，再次假定： 0^ = 142=5,0^ = 10，而 4 = 1^2=2,3=3。 最初在任何分配之前’該原始子載波之有效SNR，〜僅 係其原始SNR ’、，其意味著： 迭代0 : yi = l，y2=5 , y3=l〇。 接著將具有最大SNR且尚未分配之ARQ子載波（即y?3)分 配給至此具有最小有效SNr且尚未分配之原始子载波（即 yi)，其意味著： 迭代 1 :力=4，y2=5 ’ y3 = l〇。 至此’結果對於圖4之多個ARQ-SA範例皆相同。但是’ 現在，所施加的額外約束產生不同的解。 將具有最大SNR且尚未分配之arq子載波（即#2)分配給 至此具有最小有效SNR且尚未分配之原始子載波（即巧）’ 134650.doc -18- 200926670 其意味著： 迭代 2 : 7i=4，y2=7，y3 = l〇。 y3 = l〇 0 最後將具有最大SNR且尚未分配之 配給至此具有最小有效SNR且尚未分 之ARQ子載波（即A)分 分配之原始子載波（即 73)，其意味著： 迭代 3 : y 丨=4，y2=7，y3=1 i。 y3=l 1。 由於所有ARQ子載波係用盡，故結束該分配。從圖6推 斷’每一 ARQ子載波係僅使用一次。If the MRC is used in the combiner 220 and if the "ARQ subcarriers" are used to repeat the signal carried by the mth original subcarrier, the effective SNR of the original ❿ subcarrier is therefore increased to fire. This valid SNR is defined here as it will be used in the subcarrier allocations described later. Two common subcarrier allocation schemes are illustrated, namely, a single A and a plurality of ARQ-SAs, and reference to 圊3 to 7 is illustrated by a simple example. The two schemes differ in the method by which the ARQ subcarriers are allocated to the original subcarriers. It is assumed that the CSI system of the snr in the form of the original and arq subcarriers is known. The CSI can be estimated at the transmission device 10 when the channel is reciprocal or by an explicit CSI feedback, which is used for the long-term evolution of the system 134650.doc!5 200926670 (LTE) For example, as described in 3GPP's requirements for evolved UTRA (E-UTRA) and evolved UTRAN (E-UTRAN) (Standard Technical Report 25.913). Therefore, as long as the ARQ subcarrier is preferably transmitted during the channel coherence time, the CSI according to the subcarrier SNR can be regarded as practically known. For the highest performance gain, it is clear that all ARQ subcarriers can be used. In addition, in order to directly adopt the MRC, one ARQ subcarrier should not be allocated to two or more original subcarriers. Otherwise, more advanced signal processing techniques such as interference suppression or cancellation will be required. In order to enable efficient and simple receiver processing, each ARQ subcarrier should be assigned to exactly one original subcarrier in all proposed allocation schemes. However, this point is not an essential requirement. The two ARQ-SA schemes are feasible regardless of whether one ARQ subcarrier is assigned to a primary subcarrier or multiple ARQ subcarriers are assigned to an original subcarrier. Figure 3 shows a flow diagram of a plurality of ARQ-SA schemes in which ARQ subcarriers are iteratively assigned to the original subcarriers in a subcarrier. For initialization, in step S1, the effective SNR is set to the SNR of the original subcarriers. Next, in each iteration, the strongest ARQ subcarriers that have not been allocated so far are allocated to the original subcarriers having the smallest effective SNR (step S2). The effective SNR is updated after each allocation. Finally, the assigned retransmission subcarriers can be used to retransmit the relevant data (step S3). Therefore, in the proposed multiple ARQ-SA schemes, multiple ARQ subcarriers can be allocated to each original subcarrier, that is, in each allocation iteration, the ARQ subcarriers with the largest SNR and not yet allocated are allocated. The original subcarrier with the smallest effective SNR is given to this. 134650.doc -16- 200926670 Figure 4 shows an example of one of the examples of using one ARQ subcarrier twice. In this example, assume: ai = l,o:2==5, a3 = l〇, jLp1=3, y92=2,^3=l°(gp,Ml=M2:=3.) Initially in any Before the allocation, the effective SNR of the original subcarrier, ~ is only its original SNR, which means: Iteration 〇: yi = l, y2 = 5, y3 = l〇. The ARQ subcarrier with the largest SNR and not yet allocated is now allocated (i.e., W is assigned to the original subcarrier with the least significant SNR (i.e., it means: iteration 1 . ) ^ = 4, y2 = 5, y3 = l 〇. Again 'allocate the ARQ subcarrier with the largest SNR and not yet allocated (ie 彡2) to the original subcarrier (ie yi) with the least significant SNR, which means: Iteration 2 . ' 72=5, y3 = l〇 Finally, the ARQ subcarrier with the largest SNR and not yet allocated (ie, eve 3) is assigned to the original subcarrier with the least effective SNR (ie y2) 'which means: iteration 3 . , y2=6, y3 = l The subcarrier allocation is terminated because all ARQ subcarriers are exhausted. It is inferred from FIG. 4 that the first and second ARQ subcarriers are used to repeat the first original subcarrier, and the third ARQ sub The carrier system is used to repeat the second sub-carrier. Figure 5 shows a flow chart of a single ARQ-SA scheme in which at most one ARQ subcarrier is allocated to each original subcarrier. This reduces the possible allocation of 134650.doc -17· The number of 200926670. For initialization, in step S1, the effective SNR is again The SNR of the original subcarriers is set to be the next. Then, in each iteration, the strongest ARQ subcarriers that have not been allocated so far are allocated to the original subcarriers having the smallest valid snr and not yet allocated (step S2). After the allocation, the effective SNR is updated. Finally, the allocated retransmission subcarriers can be used to retransmit the relevant data (step S3). Therefore, in each allocation iteration, the ARQ subcarriers with the largest SNR and not yet allocated are allocated to The original subcarrier with the smallest valid snr and not yet allocated is shown in Fig. 6. Fig. 6 shows one of the examples in which each ARQ subcarrier is used only once. In this example, it is assumed again: 0^ = 142=5, 0^ = 10, and 4 = 1^2 = 2, 3 = 3. Initially before any allocation 'the effective SNR of the original subcarrier, ~ is only its original SNR ', which means: Iteration 0: yi = l, y2 =5, y3=l〇. The ARQ subcarrier with the largest SNR and not yet allocated (ie y?3) is then assigned to the original subcarrier (ie yi) with the least significant SNr and not yet allocated, which means: iteration 1 : force = 4, y2 = 5 ' y3 = l〇. So far here' The same is true for the multiple ARQ-SA examples of Figure 4. But 'now, the additional constraints imposed produce different solutions. Assigning the arq subcarriers with the largest SNR and not yet allocated (ie #2) to this has the least effective SNR and the original subcarrier that has not been allocated (ie, clever)' 134650.doc -18- 200926670 It means: Iteration 2: 7i=4, y2=7, y3 = l〇. Y3 = l〇0 will finally allocate the original subcarrier (ie 73) with the largest SNR and not yet allocated to this ARQ subcarrier (ie A) with the least significant SNR and not yet divided, which means: Iteration 3 : y丨=4, y2=7, y3=1 i. Y3=l 1. Since all ARQ subcarriers are exhausted, the allocation is ended. It is inferred from Fig. 6 that each ARQ subcarrier system is used only once.
之一不意性流程圖。如此範例所解說，一更簡單的演算法 可用於獲得相同結果。 在步驟si中，從最小SNR至最大SNR對該等原始子載波 進行分類。接著，在步驟S2中，以一相反方式，從最大 SNR至最小SNR對該等ARQ子載波進行分類。當然，可以 相反順序實施步驟S1及S2。 接著’在步驟S3中’將第《個最強ARQ子載波分配給第” 個最弱原始子載波’其中《=1、2、...、max^A/i、。 若M2M2 ’則結束該分配’跳過步驟84且所分配之子载 波可用於重傳步驟S5中的資料。否則，依據步驟S3之程序 在步驟S4分配剩餘的子載波。 為了減少可能分配之數目，可將鄰近ARQ與原始子載、皮 群組化。當一組子載波上的SNR係大致相同時，此尤其有 效。接著，可在一群組化位準上使用上述單一< 多個 ARQ-SA，其中用於每一群組之SNR可以係定義為該群組 134650.doc -19- 200926670 上的平均SNR。 若群組化之子載波數目係遠遠小於該頻道之同調頻寬， 則每一群組内的該等子載波具有大致相同的Snr，在此情 況下，基於該等群組化的子載波來執行ARQ_SQ便足夠。 在每一群組内，可實施ARQ_SA之一第二（更深）位準。還 可使用用於該ARQ-SA之一固定傳統分配，例如藉由將該 原始子載波之索引循環偏移一固定數字並將其用作該等 ARQ子載波之索引。 ❹ 一 對於每一群組，一群組相等SNR可用於表示該群組之 SNR。作為一範例，該群組之最小SNR可用作該群組相等 SNR^模擬揭示此群組相等SNR之選擇與算術平均值相比 導致一較佳的位元錯誤率（BER)性能，且以類似於幾何平 均值之方式執行。 總而言之，已說明一種傳送裝置、接收裝置、重傳資料 之系統及方法’其中已在―第—組原始子载波上傳送之一 φ 信號係在一第二組重傳子載波上重傳。比較該等原始子載 波及該等重傳子載波之一傳輸品質資訊，且藉由將具有最 间傳輸〇口質且尚未在該第二組中分配之一重傳子載波分配 •，給該第-組中具有最低傳輸品質之一原始子栽波來獲得該 •第二組重傳子載波。 應注意本發明並不限於上述具體實施例而可用於具有一 重傳協定之任何多載波無m特定範例係在 族中的系統，以及基於3GPP LTE的該些系統。本發明可 應用於在-標準化系統内工作或作為讓一專有wlan在特 134650.doc •20« 200926670 定情況（例如但不限於需要醫藥服務級別品質之醫院中的 無線通信）令工作之一盡0 座叩特有特徵。任何類型的傳輸品 質資訊皆可用於推導該子載波分配。 最後但重要的係，應注意術語「包含」在用於包括 # $範圍之說0月書中時係預期用以指定所述特徵、構件、 步驟或組件之存在，但是並不排除一或多個其他特徵、構 件步驟、組件或其群組之存在或添加。另外一請求項 ❹One of the unintentional flow charts. As illustrated by this example, a simpler algorithm can be used to achieve the same result. In step si, the original subcarriers are classified from a minimum SNR to a maximum SNR. Next, in step S2, the ARQ subcarriers are classified from the maximum SNR to the minimum SNR in an opposite manner. Of course, steps S1 and S2 can be implemented in reverse order. Then 'in step S3' assigns the "strongest ARQ subcarriers" to the "nearest weakest original subcarriers" where "=1, 2, ..., max^A/i, if M2M2' then ends Assigning 'skip step 84 and the allocated subcarriers can be used to retransmit the data in step S5. Otherwise, the remaining subcarriers are allocated in step S4 according to the procedure of step S3. To reduce the number of possible allocations, neighboring ARQs can be used. Sub-carrier, pico-grouping. This is especially effective when the SNRs on a set of sub-carriers are approximately the same. Next, the above single < multiple ARQ-SAs can be used on a grouping level, where The SNR for each group can be defined as the average SNR for the group 134650.doc -19- 200926670. If the number of grouped subcarriers is much smaller than the coherence bandwidth of the channel, then within each group The subcarriers have substantially the same Snr, in which case it is sufficient to perform ARQ_SQ based on the grouped subcarriers. Within each group, one of the second (deeper) levels of ARQ_SA can be implemented. It is also possible to use a fixed conventional allocation for one of the ARQ-SAs, for example by The index of the original subcarrier is cyclically offset by a fixed number and used as an index for the ARQ subcarriers. ❹ For each group, a group of equal SNRs can be used to represent the SNR of the group. For example, the minimum SNR of the group can be used as the group equal SNR ^ simulation reveals that the selection of equal SNR for this group results in a better bit error rate (BER) performance compared to the arithmetic mean, and is similar In summary, a transmitting device, a receiving device, a system and method for retransmitting data have been described, in which one of the φ signals has been transmitted on the first group of original subcarriers in a second group of retransmissions. Retransmission on the subcarriers. Comparing the transmission quality information of the original subcarriers and one of the retransmission subcarriers, and retransmitting the subcarriers by having one of the most transmitted transmission qualities and not yet allocated in the second group Allocating the original subcarrier with one of the lowest transmission qualities in the first group to obtain the second group of retransmission subcarriers. It should be noted that the present invention is not limited to the above specific embodiments and can be used to have a retransmission agreement. The multi-carrier nom-specific system is a system in the family, and the systems based on 3GPP LTE. The invention can be applied to work in a -standardized system or as a proprietary wlan at 134650.doc •20« 200926670 Qualitative circumstances (such as, but not limited to, wireless communication in hospitals that require medical service level quality) make one of the unique features of the work. Any type of transmission quality information can be used to derive the subcarrier allocation. Last but important It should be noted that the term "comprising" is used to mean the existence of the described features, components, steps, or components, but does not exclude one or more other features or components. The presence or addition of steps, components, or groups thereof. Another request item ❹
中的- 7L件前之冠詞「一」$「一個」不排除複數個此類 兀：的出ί見。此外’任何參考符號並不限制申請專利範圍 之範嘴。 【圖式簡單說明】 現在將參考附圖基於各種具體實施例說明本發明， 等附圖中： @ 圖1顯示依據一第一具體實施例之一重傳系統之一示意 I·生方塊圖’其中重傳品質資訊係回授給傳輸側； 圖2顯示依據一第二具體實施例之一重傳系統之一示意 哇方塊圖’其中一子載波分配係回授給傳輸側； 圖3顯示一多個子載波分配方案之一示意性流程圖； 圖4顯示其中兩次使用一重傳子載波之一範例之—解 圖5顯示一單一子載波分配方案之一示意性流程圖； 圖ό顯示其中每一重傳子載波僅使用一次之一範例之一 圖解；以及 圖7顯示具有一簡化演算法之一單一子載波分配方案之 134650.doc -21- 200926670 一示意性流程圖。 【主要元件符號說明】 10 傳輸/傳輸器件 20 接收/傳輸器件 30 對應回授機構 110 傳送器 120 子載波分配單元 210 接收器 220 組合器 230 分配單元 dl ' d2 ' ... ' dM 平行資料串流 ❹ 134650.doc -22-In the middle - 7L, the article "一" $"一" does not exclude a plurality of such 兀: In addition, any reference symbol does not limit the scope of the patent application. BRIEF DESCRIPTION OF THE DRAWINGS The present invention will now be described based on various embodiments with reference to the accompanying drawings, in which: FIG. 1 shows one of the retransmission systems according to a first embodiment. The retransmission quality information is fed back to the transmission side; FIG. 2 shows one of the retransmission systems according to a second embodiment, which is a wow block diagram in which one subcarrier allocation is fed back to the transmission side; FIG. 3 shows a plurality of sub- A schematic flow chart of one of the carrier allocation schemes; FIG. 4 shows an example of one of the two retransmission subcarriers used in the solution - FIG. 5 shows a schematic flow chart of a single subcarrier allocation scheme; The subcarriers are illustrated using only one of the examples at one time; and Figure 7 shows a schematic flow diagram of 134650.doc -21 - 200926670 with a single subcarrier allocation scheme of a simplified algorithm. [Main component symbol description] 10 Transmission/transmission device 20 Reception/transmission device 30 Corresponding feedback mechanism 110 Transmitter 120 Subcarrier allocation unit 210 Receiver 220 Combiner 230 Distribution unit dl ' d2 ' ... ' dM Parallel data string Rogue 134650.doc -22-