Patent Description:
Wireless communication refers to communication among a plurality of nodes based on long-distance transmission without conductors or cables. Wireless communication has spread into all aspects of people's life and work, such as WLAN, UWB, Bluetooth, wideband satellite system, and digital TV.

Document <CIT> discloses a wireless audio communication method and apparatus and an audio playback device and system. The method comprises: a first playback device communicating wirelessly with an audio source device to acquire data sent by the audio source device; during at least part of the duration of a wireless communication process, a second playback device acquiring data from the audio source apparatus by means of data interception such that, if the second playback device acquires the data incorrectly, then the second playback device sends out an interference signal causing the audio source device to resend the data, thereby allowing the second playback device to completely receive the data delivered by the audio source device and to ensure the integrity of data received by the second playback device.

Document <CIT> discloses a method of streaming an audio signal from an audio transmission device to first and second audio receiver devices via a Bluetooth link using a protocol that requires an audio data packet to be retransmitted if a positive packet receipt is not received. The first audio receiver device is synchronized to the audio transmission device to enable the first audio receiver device to receive an audio signal stream from the audio transmission device, the second audio receiver device is synchronized to the audio transmission device to enable the second audio receiver device to eavesdrop the audio signal stream to the first audio receiver device. When a positive packet receipt acknowledgement is not transmitted from the first audio receiver device to the audio transmission device, the audio transmission device repeats transmission of that audio data packet irrespective of whether the packet has been correctly received by the first audio receiver device.

Document <CIT> describes a True Wireless Stereo (TWS) earphone communication method and system, and a TWS earphones. The method comprises the following steps: when an audio source sends a data packet and a main earphone correctly receives the data packet, the main earphone sends acknowledgment information in an acknowledgment information slot; when the data packet is incorrectly received by the main earphone, no information is sent in the acknowledgment information slot; and when the data packet is received correctly by a secondary earphone, the secondary earphone does not send any information in the acknowledgment information slot. When the data packet is not received correctly by the secondary earphone, it sends interference information in the acknowledgment information slot.

There are a variety of types of wireless communication systems, and they have their own advantages. In a wireless communication system, a plurality of nodes is set and work together. A common connection manner of wireless communication, especially in the field of Bluetooth headsets, is as follows: one node acquires data transmitted between other nodes by listening on communication between these nodes. For example, a first node establishes a wireless communication link with a second node to perform wireless communication, and also establishes a wireless communication link with a third node for wireless communication; the first node sends connection information of the wireless communication with the second node to the third node; and the third node acquires, by listening on the wireless communication link between the first node and the second node based on the connection information, transmission data sent by the second node to the first node. Wireless communication can be directly performed between the first node and the second node, but cannot be directly performed between the second node and the third node, which adversely affects running of a feedback mechanism and a retransmission mechanism for data transmission in wireless communication, and further reduces transmission quality. For example, the second node sends the transmission data to the first node, and the third node receives the transmission data via listening. The first node feeds back an acknowledge character to the second node if it successfully receives the transmission data; or the first node feeds back a negative acknowledge character to the second node if it fails to receive the transmission data, thereby enabling the second node to perform data retransmission. However, the third node cannot directly give feedback to the second node. If the third node fails to receive the transmission data via listening, but the first node successfully receives the transmission data, the second node does not perform retransmission.

To resolve this problem, a researcher proposes the following method for synthesizing feedback results. After receiving the transmission data, the third node gives feedback to the first node in an idle period of a receiving slot; and the first node synthesizes its own receiving status and a receiving status of the third node, and feeds back an acknowledge character to the second node if both the first node and the third node successfully receive the transmission data; or the first node feeds back a negative acknowledge character to the second node if either of the two nodes fails to receive the transmission data, thereby enabling the second node to perform data retransmission. This avoids impact on running of the feedback mechanism and the retransmission mechanism for data transmission in wireless communication, and guarantees transmission quality.

However, under normal circumstances, most of the transmission data can be successfully received, which means that only a small amount of the transmission data needs to be retransmitted. Therefore, in most cases, actions performed within the idle period of the slot not only are useless, but also waste resources and increase costs. In addition, for some wireless communication systems, for example, a wireless communication system of a Bluetooth headset, there is a certain tolerance to packet loss. Even under a circumstance in which packet loss is caused by RF interference, the Bluetooth headset can still achieve good audio quality, provided that some good packet hiding algorithms are used.

According to the invention, there is provided a system as defined in claim <NUM> and a method as defined in claim <NUM>. Further developments of the invention are part of the dependent claims.

A first objective of the present disclosure is to provide a wireless communication system, which can guarantee running of a feedback mechanism and a retransmission mechanism for data transmission in wireless communication, lower costs, and reduce resource waste.

The following provides further descriptions in detail with reference to specific embodiments.

As basically shown in <FIG> , this embodiment is as follows. A wireless communication system includes a first node, a second node, and a third node, wherein the first node establishes a wireless communication link with the second node to perform wireless communication, and forwards connection information of the wireless communication to the third node; and the third node receives, by listening on the wireless communication link based on the connection information, transmission data sent by the second node to the first node. In other words, the first node and the second node directly perform the wireless communication with each other, as shown by a solid line in <FIG> ; but the second node and the third node cannot directly perform wireless communication with each other, as shown by a dashed line in <FIG>. The third node can receive, only by listening on the communication between the first node and the second node, the transmission data sent by the second node to the first node, thereby performing the wireless communication.

If an error occurs when the third node receives the transmission data sent by the second node to the first node, the third node interferes with the first node's reception of the transmission data sent by the second node, so that an error is caused when the first node receives the transmission data sent by the second node, and the second node is triggered to perform retransmission. Specifically, the third node receives, by listening on the communication between the first node and the second node, the transmission data sent by the second node to the first node, and verifies the transmission data from head to tail to check whether the transmission data has an error or whether an error occurs during the transmission. If the transmission data has the error or the error occurs during the transmission, the third node switches from a receiving mode to a sending mode, and sends an interference signal to the first node, so that the error is caused when the first node receives the transmission data sent by the second node, and the second node is triggered to perform retransmission.

If the wireless communication is Bluetooth communication, the transmission data is a data packet. As shown in <FIG> , the data packet includes three parts: an access code (ACCESS CODE in the figure), a packet header (HEADER in the figure), and data (PAYLOAD in the figure). The data packet is a standard data packet compliant with the Bluetooth specification. Specifically, the third node verifying the transmission data from head to tail is: the third node sequentially verifies the access code, the packet header, and the data by a channel access code, header error check HEC, and payload check using CRC, respectively; and when detecting that any part has an error or that an error occurs during the transmission, the third node switches from a receiving mode to a sending mode, and sends an interference signal to the first node, wherein after completing reception of the transmission data, the first node keeps in the receiving mode for a preset time period within a receiving slot, wherein the preset time period does not exceed the receiving slot. In other words, in the Bluetooth communication, after completing reception of the data in the data packet, the first node keeps in the receiving mode for the preset time period within the receiving slot. Therefore, the interference signal sent when the third node detects an error or a transmission error by verifying the data can also be received by the first node. That is, the first node receives more data than the transmission data that can be sent by the second node. The first node uses the transmission data received from the second node and the third node as a whole data packet, and checks CRC or integrity of the whole data packet, thereby guaranteeing the interference effect of the interference signal.

A working principle of the above is as follows. The third node receives, by listening on the communication between the first node and the second node, the transmission data sent by the second node to the first node. If both the third node and the first node successfully receive the transmission data, the first node feeds back an acknowledge character to the second node. If the first node fails to receive the transmission data, no matter whether the third node successfully receives the transmission data, the first node feeds back a negative acknowledge character to the second node, and the second node performs retransmission after receiving the negative acknowledge character. If the third node fails to receive the transmission data, that is, an error occurs when the third node receives the transmission data sent by the second node to the first node, the third node interferes with the first node's reception of the transmission data sent by the second node, so that an error is caused when the first node receives the transmission data sent by the second node, the first node feeds back a negative acknowledge character to the second node, and the second node is triggered to perform retransmission. This avoids impact on running of the feedback mechanism and the retransmission mechanism for data transmission in wireless communication, and guarantees transmission quality. In addition, under normal circumstances, most of the transmission data can be successfully received by the third node and the first node. In this case, the system performs feedback normally according to the protocol of an underlying wireless system; and for a small amount of the transmission data that fails to be successfully received by the third node and/or the first node, feedback and retransmission are performed based on the above content. Therefore, the third node and the first node do not need to perform integrated feedback once or multiple times in each idle period of the slot, which reduces resource waste and lowers costs.

As shown in <FIG> , this embodiment uses a wireless communication system for connection between a true wireless Bluetooth headset and a mobile phone as an example. As shown in <FIG> , abbreviations in the accompanying drawings are described as below:.

In case <NUM>, both SNK-<NUM> and SNK-<NUM> successfully receive the data packet sent by SRC, and SRC receives ACK fed back by SNK-<NUM>.

In case <NUM>, if SNK-<NUM> fails to identify the access code of SRC, SNK-<NUM> immediately switches from an RX mode (receiving mode) to a TX mode (sending mode) to send a randomly constructed interference signal for preventing SNK-<NUM> from correctly receiving the rest part of the data packet. Although SNK-<NUM> may not know how many slots SLOT N can last for, because a length of a data packet is fixed within certain duration, a length of SLOT N can be calculated based on packets that are previously received successfully. SNK-<NUM> sends NACK to SRC within SLOT N+<NUM>.

In case <NUM>, SNK-<NUM> correctly identifies the access code, but fails to receive the packet header. SNK-<NUM> performs switching from the RX mode to the TX mode at the beginning of TX-PLD to send a randomly constructed data packet, and SNK-<NUM> keeps in the TX mode close to the end of SLOT. Although SNK-<NUM> may not know how many slots SLOT N can last for, because a length of a data packet is fixed within certain duration, a length of SLOT N can be calculated based on packets that are previously received successfully. SNK-<NUM> sends NACK to SRC within SLOT N+<NUM>.

In case <NUM>, SNK-<NUM> correctly identifies the access code and the packet header of SRC, but fails to receive the data. SNK-<NUM> switches to the TX mode when the reception ends, and sends some data, namely, an interference signal, that can be easily identified by SNK-<NUM>. SNK-<NUM> receives more data than the data packet that can be sent by SRC, and continuously receives data bits from SNK-<NUM> in a manner similar to receiving data from SRC until a timer expires. Then, SNK-<NUM> uses data received from SRC and SNK-<NUM> as a whole data packet, and checks CRC or integrity of the whole data packet. Because checking the CRC or integrity fails, SNK-<NUM> sends NACK to SRC within SLOT N+<NUM>. However, if SNK-<NUM> does not send the interference signal, whether checking passes only depends on whether SNK-<NUM> correctly receives the data.

In cases <NUM>, <NUM>, and <NUM>, when failing to correctly receive the data packet sent by SRC, SNK-<NUM> interferes with SNK-<NUM>'s reception to enable SRC to send the packet again. However, the interference may fail. Application is not impacted even when the interference fails. Because packet hiding algorithms can be used to compensate for data in actual application, good audio quality can still be achieved.

As basically shown in <FIG> , this embodiment is as follows. A wireless communication method is applied to a communication network including a first node, a second node, and a third node, wherein the first node establishes a wireless communication link with the second node to perform wireless communication, and forwards connection information of the wireless communication to the third node; and the third node receives, by listening on the wireless communication link based on the connection information, transmission data sent by the second node to the first node. In the communication network, the first node establishes the wireless communication link with the second node to directly perform the wireless communication, and forwards the connection information of the wireless communication to the third node; but the second node and the third node cannot directly perform wireless communication with each other. The third node can receive, only by listening on the wireless communication link based on the connection information, the transmission data sent by the second node to the first node.

In S1, whether an error occurs when the third node receives the transmission data sent by the second node to the first node is determined, wherein if yes, S2 is performed. S1 specifically includes the following sub-steps.

In S101, the third node receives the transmission data sent by the second node to the first node.

In S102, the third node verifies the transmission data from head to tail to detect whether the transmission data has an error or whether an error occurs during the transmission, wherein if yes, S2 is performed.

In S2, the third node interferes with the first node's reception of the transmission data sent by the second node, wherein due to the interference, an error is caused when the first node receives the transmission data sent by the second node, and the second node is triggered to perform retransmission. S2 specifically includes the following sub-steps:.

The wireless communication is Bluetooth communication. The transmission data is a data packet. The data packet includes three parts: an access code, a packet header, and data. S102 includes: sequentially verifying the access code, the packet header, and the data by the third node by using a channel access code, header error check HEC, and payload check using CRC, respectively, wherein S2 is performed if a result shows that any part has an error or that an error occurs during the transmission; and after the first node completes reception of the transmission data, keeping the first node in a receiving mode for a preset time period within a receiving slot, wherein the preset time period does not exceed the receiving slot. In other words, in the Bluetooth communication, after completing reception of the data in the data packet, the first node keeps in the receiving mode for the preset time period within the receiving slot. Therefore, the interference signal sent when the third node detects an error or a transmission error by verifying the data can also be received by the first node. That is, the first node receives more data than the transmission data that can be sent by the second node. The first node uses the transmission data received from the second node and the third node as a whole data packet, and checks CRC or integrity of the whole data packet, thereby guaranteeing the interference effect of the interference signal.

A working principle of the above is as follows. The third node receives the transmission data sent by the second node to the first node. If both the third node and the first node successfully receive the transmission data, the first node feeds back an acknowledge character to the second node. If the first node fails to receive the transmission data, no matter whether the third node successfully receives the transmission data, the first node feeds back a negative acknowledge character to the second node, and the second node performs retransmission after receiving the negative acknowledge character. If the third node fails to receive the transmission data, that is, an error occurs when the third node receives the transmission data sent by the second node to the first node, the third node interferes with the first node's reception of the transmission data sent by the second node, so that an error is caused when the first node receives the transmission data sent by the second node, the first node feeds back a negative acknowledge character to the second node, and the second node is triggered to perform retransmission. This avoids impact on running of the feedback mechanism and the retransmission mechanism for data transmission in wireless communication, and guarantees transmission quality. In addition, under normal circumstances, most of the transmission data can be successfully received by the third node and the first node. In this case, the system performs feedback normally according to the protocol of an underlying wireless system. For a small amount of the transmission data that fails to be successfully received by the third node and/or the first node, feedback and retransmission are performed based on the above content. Therefore, the third node and the first node do not need to perform integrated feedback once or multiple times in each idle period of the slot, which reduces resource waste and lowers costs.

Claim 1:
A wireless communication system, comprising: a first node, a second node, and a third node, wherein the first node is configured to establish a wireless communication link with the second node to perform wireless communication, and is further configured to forward to the third node connection information of the wireless communication between the first node and the second node; and the third node is configured to receive, by listening on the wireless communication link based on the connection information, transmission data sent by the second node to the first node;
wherein the wireless communication is Bluetooth communication;
wherein the transmission data is a data packet comprising three parts: an access code, a packet header, and data;
wherein the third node is configured to sequentially verify the access code, the packet header, and the data such that, when the third node detects that any of the three parts has an error, then the third node switches from a receiving mode to a sending mode and sends an interference signal to the first node, said interference signal being configured to cause an error in the reception by the first node of the transmission data sent by the second node; and
wherein the access code, the packet header, and the data are sequentially verified by a channel access code, header error check HEC, and payload check using CRC, respectively.