1290798 九、發明說明： 【發明所屬之技術領域】 本發明係關於無線區域網路之技術領域，尤指一種適 用於無線區域網路之立即重傳方法及系統。 5 【先前技術】 1997年制定的IEEE 802.11為目前無線區域網路 (wireless local area network，簡稱WLAN)的主要標準，其 中規範了 WLAN中物理層（physic，簡稱PHY)和媒介存取控 10 制層（medium access control，簡稱 MAC)的運作。IEEE 802.1 1 DCF (distributed coordination function)定義 了無線行動裝置（station)存取無線媒介的基本方法。無線 網路是一個共享的媒介，DCF是一種以競爭為主的方式來 達到存取控制，使用CSMA/CA的觀念。由於無線區域網路 15 是個傳輸不穩定的媒介，DCF採用Positive ACK作為確認 是否正確接收的方式。如圖1(a)所示，Positive ACK係指在 一個傳送端送一訊框給接收端的過程裏，接收端每當正確 無誤地收到一個訊框後，會回覆一個確認（Acknowledge, 簡稱ACK);而發送端送出一個訊框後，直到收到接收端的 20 確認，才能送出下一個訊框。若是發送端在等待一段時間 (Retransmission Timeout)沒收到接收端的確認’會認疋為 傳送失敗，而再重新傳送這個訊框，如圖1 (b)。 圖2進一步顯示發生訊框傳送漏失時，發送端需等待 一段相當長之時間（timeout)後，才會重新傳送資料訊框’ 1290798 而在此等待的時間裏，所有在同一無線網路的無線行動裝 置，無法傳送，故將對已經十分稀少的無線網路資源造成 可觀的浪費，因而導致網路效能低落。因此，減少Timeout ‘生的頻率以有效地增加無線頻帶的使用率，實為一亟待 5 解決之問題。 。 【發明内容】 本t明之主要目的係在提供一種無線區域網路之立 即重傳方法及系統，其可減少Time_發生的頻率以有效地 10增加無線頻帶的使用率，以提高網路系統效能。 依據本發明之一特色，係提出一種無線區域網路之立 即重傳方法，其中，無線區域網路至少具有一第一無線行 動裝置、一第二無線行動裝置及一無線存取器或領導節 點，該第一無線行動裝置欲直接傳送資料給該第二無線行 15動裝置，該方法包括步驟：一傳送資料步驟，係由第一無 線行動衣置傳送資料訊框給第二無線行動裝置；一要求重 傳步驟，若無線存取器或領導節點收到一錯誤之資料訊 忙則廣播送出一重傳要求（Retransmission.Request);以 及一立即重傳步驟，當先前傳送該資料訊框之第一無線行 20動裝置收到該重傳要求（Retransmissi〇n Re^est)時，立即 重傳該資料訊框。 依據本發明之另一特色，係提出一種無線區域網路之 立即重傳系統，其包括··一第一無線行動裝置及一第二無 線行動裝置，該第一無線行動裝置傳送一資料訊框給第二 1290798 無線行動裝置；一無線存取器或領導節點，其在收到一錯 誤之資料訊框時，廣播送出一重傳要求 (Retransmission.Request);其中，當先前傳送該資料訊框 之第一無線行動裝置收到該重傳要求 5 (Retransmission.Request)時，立即重傳該資料訊框。 【實施方式】 有關本發明之無線區域網路之立即重傳方法及糸 統，請先參照圖3所示之系統架構圖，其為一有無線存取器 10 (AP)之無線區域網路（infrastructure WLAN)環境，其中，在 一無線存取器21控制之範圍内有兩個可以彼此通訊之無線 行動節點22及23，無線行動節點22可直接傳送資料訊框給 無線行動節點23。 一併參照圖4所示之訊息流程圖，當無線行動節點22 15 欲傳送資料訊框時，無線行動裝置22(傳送端）先送出一個 「要求傳送」控制訊框（Request to Send，RTS)，而無線行 動裝置23(接收端）在收到這個控制訊框之後，等待一個 SIFS(Short Inter Frame Space)時間，然後回送「允許傳送」 控制訊框（Clear to Send，CTS)。一旦無線行動裝置22收到 20 CTS，便在SIFS時間之後傳送資料（Data)訊框給無線行動裝 置23。 此時，無線存取器21可以作監聽所有的訊框（frame)， 若是無線行動裝置23正確收到資料訊框（無線存取器21亦 應正確收到資料訊框），則無線行動裝置23等待SIFS，然後 1290798 回傳確4 (ACK)訊框。若無線存取器21發現有訊框漏失 (frameioss)時，亦即是收到資料訊框後，無線存取器以檢 查其C R C出現錯誤（無線行動裝置2 3亦無法正確收到資料 訊框）。由於該資料訊框出現錯誤，無線存取器㈣無法知 5道該錯言吳的資料訊框之傳送者，於是以廣播加⑽心⑽）的 方式送出重傳要求（Retransmission.Request),以要求先 刖有傳运貢料訊框的傳送者（亦即，無線行動裝置2幻立即 重傳。 當先則傳送該資料訊框之無線行動裝置22收到重傳 10要求（Retransmissi〇n.Request)時，則立即重傳該資料訊 框，而不必再重新競爭。 圖5 s、、員示本發明之無線區域網路之立即重傳方法及系 統的另一貫施例，其為一無線隨意網路（Ad h〇幻之環境， 其中，疋以無線隨意網路之領導節點5i(ieder n〇de，lN， 15無線隨意網路中第一個發出同步訊號之節點）取代前一實 加例之热線存取為2!，來監聽所有的訊框，以當發現有訊 框漏失時，以廣播的方式送出一重傳要求 (R价ansmission.Request)，來要求先前有傳送資料訊框的 傳送者立即重傳。其工作原理與前一實施例相當而不再詳 20 述。 由以上之說明可知，本發明利用無線訊號廣播及無線 f取器或領導節點可以收到大部分無線行動節闕傳送的 这的特f生’以虽因無線訊號因干擾（interfere⑽）或衝撞 (collmcm)發生訊框漏失時，接收端與無線存取器或領導節 1290798 點都會收到訊框的訊號，但是經CRC的檢測後發現訊框錯 為此日^無線存取裔或領導節點會在一段時間内（sips)， 馬上廣播送出一個重傳要求（Retransmissi〇n Request)，告 訴發送端這個訊框傳送失敗，而發送端可以立即重傳送此 5資料訊框。如此發送端可以在發現錯誤後，馬上發現並重 ^不須要專待一段時間。因此本發明可省去不必要的 timeout及避免頻帶的浪費而有效利用無線頻帶珍貴資源 來提鬲網路系統效能，因而加快重傳的速度，且在訊框漏 失率高的環境下，仍可以運作良好，亦與現行8〇211完全 10 相容。 上述實施例僅係為了方便說明而舉例而已，本發明所 主張之權利範圍自應以申請專利範圍所述為準，而非僅限 於上述實施例。 15【圖式簡單說明】 圖1 (a)顯示WLAN中一個傳逆嫂占从w b 得k立而成功迗出一訊框給接收端 的過程。 圖1(b)顯示WLAN中一個傳逆矬去处々[ 而未月b成功送出一訊框給接 收端而重新傳送的過程。 20圖2顯示發生訊框傳送漏失時之訊框傳送流程圖。 圖3為本發明之無線區域網路之立即重❹ 之架構圖。 圖4為本發明之無線區域網 <立即重傳方法的之流程圖。 1290798 圖5為本發明之無線區域網路之立即重傳系統的另一實施 例之架構圖。 【主要元件符號說明】 5 21無線存取器 22, 23無線行動節點 5 1領導節點1290798 IX. Description of the Invention: [Technical Field] The present invention relates to the technical field of wireless local area networks, and more particularly to an instantaneous retransmission method and system suitable for a wireless local area network. 5 [Prior Art] IEEE 802.11, which was established in 1997, is the main standard of wireless local area network (WLAN). It regulates the physical layer (physic, PHY for short) and medium access control system in WLAN. The operation of the medium access control (MAC). IEEE 802.1 1 DCF (distributed coordination function) defines a basic method for wireless mobile devices to access wireless media. The wireless network is a shared medium, and DCF is a competition-based approach to access control using the CSMA/CA concept. Since the wireless local area network 15 is a medium with unstable transmission, the DCF uses a Positive ACK as a means of confirming whether or not it is correctly received. As shown in Figure 1(a), Positive ACK refers to the process of sending a frame to a receiving end on a transmitting end. When the receiving end receives a frame correctly, it will reply with an acknowledgement (Acknowledge, ACK for short). After the sender sends out a frame, it will not send the next frame until it receives the 20 confirmation from the receiver. If the sender does not receive the acknowledgement from the receiver after waiting for a period of time (Retransmission Timeout), it will recognize that the transmission failed, and then retransmit the frame, as shown in Figure 1 (b). Figure 2 further shows that when a frame transmission loss occurs, the sender waits for a considerable period of time before retransmitting the data frame '1290798. During this waiting time, all wireless in the same wireless network. The mobile device cannot be transmitted, so it will cause considerable waste of the already scarce wireless network resources, resulting in low network performance. Therefore, reducing the frequency of Timeout's generation to effectively increase the usage rate of the wireless band is a problem that needs to be solved. . SUMMARY OF THE INVENTION The main purpose of the present invention is to provide an instantaneous retransmission method and system for a wireless local area network, which can reduce the frequency of Time_ to effectively increase the usage rate of the wireless frequency band to improve the performance of the network system. . According to a feature of the present invention, an instant retransmission method for a wireless local area network is provided, wherein the wireless local area network has at least a first wireless mobile device, a second wireless mobile device, and a wireless accessor or a leader node. The first wireless mobile device intends to directly transmit data to the second wireless mobile device 15 . The method includes the following steps: a data transfer step of transmitting a data frame to the second wireless mobile device by the first wireless mobile device; A request for retransmission, if the wireless accessor or the leader node receives an error message, the broadcast sends a retransmission request (Retransmission.Request); and an immediate retransmission step, when the data frame is previously transmitted When the wireless line 20 mobile device receives the retransmission request (Retransmissi〇n Re^est), the data frame is retransmitted immediately. According to another feature of the present invention, an immediate retransmission system for a wireless local area network is provided, comprising: a first wireless mobile device and a second wireless mobile device, wherein the first wireless mobile device transmits a data frame Giving a second 1290798 wireless mobile device; a wireless accessor or a leader node, when receiving an error message frame, broadcasting a retransmission request (Retransmission. Request); wherein, when the data frame is previously transmitted When the first wireless mobile device receives the retransmission request 5 (Retransmission.Request), it immediately retransmits the data frame. [Embodiment] Regarding the method and system for the instant retransmission of the wireless local area network of the present invention, please refer to the system architecture diagram shown in FIG. 3, which is a wireless local area network with a wireless accessor 10 (AP). An (infrastructure WLAN) environment in which there are two wireless mobile nodes 22 and 23 that can communicate with each other within the control of a wireless access device 21, and the wireless mobile node 22 can directly transmit the data frame to the wireless mobile node 23. Referring to the message flow chart shown in FIG. 4, when the wireless mobile node 22 15 wants to transmit the data frame, the wireless mobile device 22 (transmitting terminal) first sends a "Request to Send" (Request to Send, RTS) message frame. The wireless mobile device 23 (receiver) waits for a SIFS (Short Inter Frame Space) time after receiving the control frame, and then returns a "Clear to Send" (CTS) control frame. Once the wireless mobile device 22 receives the 20 CTS, it transmits a Data frame to the wireless mobile device 23 after the SIFS time. At this time, the wireless access device 21 can monitor all the frames. If the wireless mobile device 23 correctly receives the data frame (the wireless access device 21 should correctly receive the data frame), the wireless mobile device 23 Wait for SIFS, then 1290798 returns the 4 (ACK) frame. If the wireless access device 21 finds frame missing frames, that is, after receiving the data frame, the wireless access device checks for a CRC error (the wireless mobile device 2 3 cannot correctly receive the data frame). ). Due to an error in the data frame, the wireless access device (4) cannot know the transmitter of the data frame of the typo, and then sends a retransmission request (Retransmission.Request) in the form of a broadcast plus (10) heart (10). It is required to first transmit the transmitter of the tribute frame (ie, the wireless mobile device 2 is immediately retransmitted. The wireless mobile device 22 transmitting the data frame first receives the retransmission request 10 (Retransmissi〇n.Request) When the data frame is retransmitted immediately, there is no need to re-competition. Figure 5 s, the member of the present invention, the wireless local area network instant retransmission method and another embodiment of the system, which is a wireless random Network (Ad h 〇 之 environment, where 疋 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线 无线For example, the hotline access is 2!, to listen to all the frames, to send a retransmission request (R price ansmission.Request) to the broadcast request when there is a frame missing. The transmitter is retransmitted immediately. Its work The foregoing embodiment is equivalent to the previous embodiment and will not be described in detail. From the above description, the present invention can use the wireless signal broadcast and the wireless f-fetcher or the leader node to receive the majority of the wireless action thrift. 'When the frame is lost due to interference (interfere(10)) or collision (collmcm), the receiver and the wireless accessor or the leader node 1290798 will receive the frame signal, but after the CRC detection, the message is found. The frame is wrong for this day. ^Wireless accessor or leader node will broadcast a retransmission request (Retransmissi〇n Request) for a period of time (sips), telling the sender that the frame transmission failed, and the sender can immediately The 5 data frame is retransmitted, so that the sender can immediately discover and re-do it without waiting for a period of time after the error is found. Therefore, the present invention can save unnecessary timeout and avoid waste of frequency band and effectively utilize the precious resources of the wireless band. To improve the performance of the network system, thus speeding up the retransmission, and in the environment with high frame loss rate, it can still work well, and the current 8〇211 The above embodiments are only examples for convenience of description, and the scope of the claims should be based on the scope of the patent application, and is not limited to the above embodiments. 15 [Simple description] Figure 1 (a) shows the process in which a VS in the WLAN takes up the frame from the wb and successfully sends out a frame to the receiver. Figure 1(b) shows a pass-through in the WLAN [and not succeeded in the month b) The process of sending a frame to the receiving end for retransmission. Fig. 2 shows a flow chart of the frame transmission when the frame transmission is lost. Fig. 3 is an architectural diagram of the wireless local area network of the present invention. 4 is a flow chart of a wireless area network < immediate retransmission method according to the present invention. 1290798 FIG. 5 is a block diagram of another embodiment of an immediate retransmission system for a wireless local area network of the present invention. [Main component symbol description] 5 21 wireless accessor 22, 23 wireless mobile node 5 1 leadership node
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