Channel access methods, apparatus, electronic devices and readable storage media

Abstract

This application provides a channel access method, apparatus, electronic device, and readable storage medium. The method includes: transmitting first data to a second node on a channel; and in response to the existence of a first remaining Network Allocation Vector (NAV) duration on the channel by the first node, transmitting first NAV sharing information to a target node on the channel. The first NAV sharing information instructs the target node to transmit data on the channel. The target node is either the second node or a third node, and the service channel of the third node is the channel accessed by the first node, which is different from the second node. In this application, the target node can utilize the remaining NAV duration of the first node to transmit data on the channel. The target node does not need to compete for channel access; instead, it directly transmits second data on the channel within the remaining NAV duration of the first node. This improves the target node's channel access capability, reduces channel contention and collisions, lowers channel access latency, and increases throughput.

Description

Technical Field

[0001] This application relates to communication technology, and more particularly to a channel access method, apparatus, electronic device, and readable storage medium. Background Technology

[0002] With the popularization of Wi-Fi technology, more and more nodes are competing for access channels, making it more difficult for nodes to access channels and increasing the probability of data transmission failures and collisions, resulting in longer latency in interactions between nodes.

[0003] Currently, in the distributed coordination function (DCF) mode, only one node can access the channel at any given time. Before accessing the channel, a node needs to monitor the channel status. If the channel is idle, the node enters a backoff state. If the channel is still idle when the backoff ends, the node can transmit data on the channel. If the node fails to transmit data on the channel, the node's backoff time will increase, causing unnecessary channel access delay. If the node successfully transmits data on the channel, the node considers the channel idle, and the node's backoff time will decrease, which can easily lead to contention and collisions.

[0004] In the current DCF mode, it is difficult and time-consuming for nodes to access the channel. Summary of the Invention

[0005] This application provides a channel access method, apparatus, electronic device, and readable storage medium, which can reduce the difficulty for nodes to access channels and reduce latency.

[0006] In a first aspect, embodiments of this application provide a channel access method. The execution subject of this method can be a first node, or a chip or processor within the first node. The following description uses the first node as the execution subject. The method includes: the first node sending first data to a second node on the channel. The first node can be a node contending for channel access, and the second node is the peer node of the first node. When the first data transmission is completed, or when the first node determines that the first data transmission is about to be completed, it can detect whether the first node has a first remaining network allocation vector (NAV) duration on the channel.

[0007] If the first node has a first remaining Network Allocation Vector (NAV) duration on the channel, then the first node can send first NAV sharing information to the target node on the channel. This first NAV sharing information instructs the target node to send data on the channel. The target node is either the second node or the third node, and the service channel of the third node is the channel in question. The third node is different from the second node. In other words, the third node is a node that is competing for access to the channel where the first node is located, and the third node is a non-peer node of the first node.

[0008] In this embodiment, the target node can utilize the remaining NAV duration of the first node to transmit data on the channel, avoiding channel idleness and improving channel utilization. Furthermore, the target node does not need to compete for channel access; instead, it directly transmits data on the channel within the remaining NAV duration of the first node, improving its channel access capability, reducing channel contention and collisions, lowering access latency, and increasing throughput. Additionally, because the NAV duration of the first node has not yet decreased to 0, other nodes (nodes other than the first and second nodes) will not compete for channel access, resulting in a high success rate for the target node to transmit data within the first remaining NAV duration.

[0009] It should be understood that, in one embodiment, if a first node detects that it has a first NAV duration on the channel, it can detect whether the first NAV duration can be used by the target node to send data. Specifically, the first node may, in response to the existence of a first remaining NAV duration on the channel, and the first remaining NAV duration being greater than or equal to a first preset duration, send the first NAV sharing information to the target node on the channel.

[0010] In this embodiment, when the first node detects that the duration of the first remaining NAV is greater than or equal to the first preset duration, it sends the first NAV sharing information to the target node. This avoids the problem that the first node sends the first NAV sharing information when the duration of the first remaining NAV is short, resulting in high power consumption of the first node and the first remaining NAV duration not being available for the target node.

[0011] The following section first explains how the first node selects the target node:

[0012] Firstly, in one possible implementation, the first node can determine whether to send the first NAV sharing information (i.e., share the first remaining NAV duration) to the second or third node based on the node's priority. The first node can choose the node with the highest priority as the target node. Thus, in this embodiment, it can be guaranteed that the node with the highest priority will execute the service first.

[0013] Secondly, in one possible implementation, the first node can determine whether to send the first NAV sharing information to the second or third node based on the first remaining NAV duration. In one embodiment, if the first remaining NAV duration is greater than or equal to a first preset duration and less than a second preset duration, the first node can use the second node as the target node. If the first remaining NAV duration is greater than or equal to the second preset duration, the first node can use the third node as the target node, where the second preset duration is greater than the first preset duration. Thus, in this embodiment, based on the first remaining NAV duration, it can be ensured that all target nodes can successfully execute their own services.

[0014] Next, we will explain how the first node determines the third node among multiple nodes competing for access to the channel:

[0015] Firstly, in one possible implementation, the first node can determine a third node that shares the first remaining NAV duration among multiple nodes competing for access to the channel, based on service priority. The third node can be the node with the highest service priority. Thus, in this embodiment, the smooth execution of high-priority services can be guaranteed.

[0016] Secondly, in one possible implementation, the first node can determine a third node that shares the first remaining NAV duration among multiple nodes competing for channel access, based on the duration of the channel not being accessed. Specifically, the first node can choose the node with the longest channel not access duration as the third node. Thus, in this embodiment, it can be ensured that nodes that have not accessed the channel for a long time can access the channel and perform services, avoiding the problem of nodes that have not accessed the channel for a long time being unable to perform services.

[0017] The method by which the first node sends the first NAV sharing information to the target node will be described again. The first NAV sharing information includes: the first remaining NAV duration, and / or an identifier indicating the completion of the first data transmission. For example, the identifier indicating the completion of the first data transmission could be an end flag.

[0018] Firstly, in one possible implementation, the first node may send a Mutual Assist Channel Access (Aid) frame to the target node on the channel, the Aid frame including the first NAV sharing information. For example, the first node may carry the first NAV sharing information in the Frame body field of the Aid frame. This approach is suitable when the target node is a second or third node.

[0019] Secondly, in one possible implementation, when the target node is the second node, since the first node can send the first data to the second node, and the first data consists of at least one data packet, the first node can carry the first NAV shared information in the last data packet of at least one data packet.

[0020] In one possible implementation, when the target node is a second node, the target node, in response to the first NAV sharing information from the first node, can feed back second data to the first node. In one embodiment, in response to the second data, if the first node detects that it has a second remaining NAV duration on the channel, and that the second remaining NAV duration is longer than a first preset duration, then the first node can send the second NAV sharing information to other nodes on the channel. The second NAV sharing information instructs the other nodes to send data on the channel. In other words, the first node can also share the second remaining NAV duration with other nodes to improve channel utilization.

[0021] In one possible implementation, when the target node has no data to send, it can send first information to the first node, indicating that the target node has no data to send. Accordingly, in response to this first information, the first node can send second NAV sharing information to other nodes, instructing them to send data on the channel.

[0022] In one possible implementation, the first node can set the NAV duration on the channel when competing for access to the channel, and the NAV duration of the first node is continuously decreasing by countdown. Therefore, when the NAV duration of the first node decreases to 0, the first node can compete with the second node and the third node again to access the channel.

[0023] Secondly, embodiments of this application provide a channel access method. The execution entity of this method can be a target node, or a chip or processor within the target node. The target node can be a second node or a third node, where the second node is a peer node of the first node, and the third node is a node that requests access to the channel where the first node resides. The method includes: receiving first network allocation vector (NAV) sharing information from the first node on the channel. The first NAV sharing information instructs the target node to transmit data on the channel. The target node is either a second node or a third node, where the second node is a peer node of the first node, or the service channel of the third node is the channel in question, and the third node is different from the second node.

[0024] In one possible implementation, receiving the first network allocation vector (NAV) sharing information from the first node on the channel includes: receiving a mutual assistance channel access (AID) frame from the first node on the channel, the AID frame including the first NAV sharing information.

[0025] In one possible implementation, if the target node is the second node, before receiving the first network allocation vector (NAV) sharing information from the first node on the channel, the method further includes: receiving first data from the first node on the channel, the first data consisting of at least one data packet, and the first NAV sharing information being carried in the last data packet of the at least one data packet.

[0026] In one possible implementation, the first NAV sharing information includes: the first remaining NAV duration of the first node, and / or an identifier indicating the completion of the first data transmission from the first node.

[0027] In one possible implementation, the third node is either a node whose uncontested access channel duration is greater than or equal to a preset duration, or the node with the highest service priority.

[0028] In one possible implementation, after receiving the first network allocation vector (NAV) sharing information from the first node on the channel, the method further includes: based on the first remaining NAV duration of the first node, if it is determined that the transmission of the second data can be completed within the first remaining NAV duration, then sending the second data to the peer node of the target node on the channel.

[0029] In this embodiment, the target node needs to estimate whether the transmission of the second data can be completed within the first remaining NAV duration based on the first remaining NAV duration. If the transmission of the second data can be completed within the first remaining NAV duration, the target node sends the second data to the peer node on the channel, which can ensure the success rate of the transmission of the second data.

[0030] In one possible implementation, after sending the second data to the peer node of the target node on the channel, the method further includes: in response to the first node having a second remaining NAV duration on the channel and being able to complete the transmission of the third data within the second remaining NAV duration, sending the third data to the peer node of the target node on the channel.

[0031] In this embodiment of the application, the target node can send data to the peer node of the target node multiple times in succession based on the remaining NAV duration of the first node on the channel.

[0032] In one possible implementation, the second data is the smallest data unit that the target node can send.

[0033] In one possible implementation, after receiving the first network allocation vector (NAV) sharing information from the first node on the channel, the method further includes: based on the first node's first remaining NAV duration, if it is determined that the transmission of the second data cannot be completed within the first remaining NAV duration, then when the first node's NAV duration decreases to 0, competing with the first node for access to the channel, wherein the first node's NAV duration is set when the first node accesses the channel.

[0034] In one possible implementation, after receiving the first network allocation vector (NAV) sharing information from the first node on the channel, the method further includes: in response to the target node not having any data to be transmitted, sending first information to the first node, the first information indicating that the target node does not have any data to be transmitted.

[0035] In one possible implementation, after receiving the first network allocation vector (NAV) sharing information from the first node on the channel, the method further includes: in response to the target node not having any data to be transmitted, sending third NAV sharing information to other nodes, the third NAV sharing information instructing the other nodes to transmit data on the channel.

[0036] In this embodiment of the application, the target node can share the remaining NAV duration of the first node with other nodes to improve channel utilization.

[0037] Thirdly, embodiments of this application provide a channel access device, including:

[0038] The transceiver module is configured to: send first data to a second node on a channel, and in response to the existence of a first remaining network allocation vector (NAV) duration on the channel by the first node, send first NAV sharing information to a target node on the channel, wherein the first NAV sharing information instructs the target node to send data on the channel, the target node being either the second node or a third node, the service channel of the third node being the channel, and the third node being different from the second node.

[0039] In one possible implementation, the transceiver module is specifically configured to: in response to the first node having a first remaining NAV duration on the channel, and the first remaining NAV duration being greater than or equal to a first preset duration, send the first NAV sharing information to the target node on the channel.

[0040] In one possible implementation, when the first remaining NAV duration is greater than or equal to the first preset duration and less than the second preset duration, the target node is the second node; when the first remaining NAV duration is greater than or equal to the second preset duration, the target node is the third node, and the second preset duration is greater than the first preset duration.

[0041] In one possible implementation, the transceiver module is specifically configured to: send a mutual assistance channel access (AID) frame to the target node on the channel, wherein the AID frame includes the first NAV sharing information.

[0042] In one possible implementation, the first data consists of at least one data packet, and the first NAV sharing information is carried in the last data packet of the at least one data packet.

[0043] In one possible implementation, the first NAV sharing information includes: the first remaining NAV duration, and / or an identifier indicating the completion of the first data transmission.

[0044] In one possible implementation, the third node is either a node whose uncontested access channel duration is greater than or equal to a preset duration, or the node with the highest service priority.

[0045] In one possible implementation, the transceiver module is further configured to: when the target node is the second node, in response to receiving second data from the second node and the first node having a second remaining NAV duration on the channel, send second NAV sharing information to other nodes on the channel, the second NAV sharing information instructing the other nodes to send data on the channel. Alternatively,

[0046] In response to receiving first information from the target node, and the first node having a second remaining NAV duration on the channel, the target node sends second NAV sharing information to other nodes on the channel, wherein the first information indicates that the target node has no data to be sent.

[0047] In one possible implementation, the processing module is configured to: set the NAV duration of the first node when the first node accesses the channel, and compete with the second node and the third node for access to the channel when the NAV duration of the first node decreases to 0.

[0048] Fourthly, embodiments of this application provide a channel access device, including:

[0049] The transceiver module is configured to: receive first network allocation vector (NAV) sharing information from a first node on a channel, the first NAV sharing information instructing the target node to transmit data on the channel, the target node being a second node or a third node, the second node being the peer node of the first node, or the service channel of the third node being the channel and the third node being different from the second node.

[0050] In one possible implementation, the transceiver module is specifically configured to: receive a mutual assistance channel access (AID) frame from the first node on the channel, the AID frame including the first NAV sharing information.

[0051] In one possible implementation, if the target node is the second node, the transceiver module is further configured to: receive first data from the first node on the channel, the first data consisting of at least one data packet, the first NAV sharing information being carried in the last data packet of the at least one data packet.

[0052] In one possible implementation, the first NAV sharing information includes: the first remaining NAV duration of the first node, and / or an identifier indicating the completion of the first data transmission from the first node.

[0053] In one possible implementation, the third node is either a node whose uncontested access channel duration is greater than or equal to a preset duration, or the node with the highest service priority.

[0054] In one possible implementation, the transceiver module is further configured to: based on the first remaining NAV duration of the first node, if it is determined that the transmission of the second data can be completed within the first remaining NAV duration, then send the second data to the peer node of the target node on the channel.

[0055] In one possible implementation, the transceiver module is further configured to: in response to the first node having a second remaining NAV duration on the channel, and being able to complete the transmission of third data within the second remaining NAV duration, send the third data to the peer node of the target node on the channel.

[0056] In one possible implementation, the second data is the smallest data unit that the target node can send.

[0057] In one possible implementation, the processing module is configured to: based on the first node's first remaining NAV duration, if it is determined that the transmission of the second data cannot be completed within the first remaining NAV duration, then when the first node's NAV duration decreases to 0, compete with the first node for access to the channel, wherein the first node's NAV duration is set when the first node accesses the channel.

[0058] In one possible implementation, the transceiver module is further configured to: in response to the target node not having data to be sent, send first information to the first node, the first information indicating that the target node does not have data to be sent.

[0059] In one possible implementation, the transceiver module is further configured to: in response to the target node not having data to be transmitted, send third NAV sharing information to other nodes, the third NAV sharing information instructing the other nodes to transmit data on the channel.

[0060] Fifthly, embodiments of this application provide an electronic device, which may be a first node, a chip within the first node, or a channel access device of a third aspect. The electronic device may include a processor and a memory.

[0061] The memory is used to store computer-executable program code, which includes instructions; when the processor executes the instructions, the instructions cause the electronic device to perform the method as described in the first aspect.

[0062] Sixthly, embodiments of this application provide an electronic device, which may be a target node, a chip within the target node, or a channel access device as described in the fourth aspect. The electronic device may include a processor and a memory.

[0063] The memory is used to store computer-executable program code, which includes instructions; when the processor executes the instructions, the instructions cause the electronic device to perform the method as described in the second aspect.

[0064] In a seventh aspect, embodiments of this application provide a computer program product containing instructions that, when run on a computer, cause the computer to perform the methods described in the first to second aspects.

[0065] Eighthly, embodiments of this application provide a computer-readable storage medium storing instructions that, when executed on a computer, cause the computer to perform the methods described in the first to second aspects.

[0066] The beneficial effects of the various possible implementations of the second to eighth aspects mentioned above can be found in the beneficial effects of the first aspect mentioned above, and will not be repeated here.

[0067] This application provides a channel access method, apparatus, electronic device, and readable storage medium. A target node can utilize the remaining NAV (Network Access Volume) of a first node to transmit data on the channel, avoiding channel idleness and improving channel utilization. Furthermore, the target node does not need to compete for channel access; instead, it directly transmits second data on the channel within the remaining NAV of the first node, improving the target node's channel access capability, reducing channel contention and collisions, lowering channel access latency, and increasing throughput. Additionally, because the NAV of the first node has not yet decreased to 0, other nodes (nodes other than the first and second nodes) will not compete for channel access, resulting in a high success rate for the target node to transmit data within the first remaining NAV. Attached Figure Description

[0068] Figure 1A This is a schematic diagram illustrating a scenario applicable to an embodiment of this application;

[0069] Figure 1B A schematic diagram illustrating a data collision caused by a hidden terminal in existing technology;

[0070] Figure 2A A flowchart illustrating one embodiment of the channel access method provided in this application;

[0071] Figure 2B A flowchart illustrating another embodiment of the channel access method provided in this application;

[0072] Figure 3 A timing diagram illustrating the shared remaining NAV duration provided in an embodiment of this application;

[0073] Figure 4 Another timing diagram illustrating the shared remaining NAV duration provided in this application embodiment;

[0074] Figure 5A Another timing diagram illustrating the shared remaining NAV duration provided in this application embodiment;

[0075] Figure 5B Another timing diagram illustrating the shared remaining NAV duration provided in this application embodiment;

[0076] Figure 6 This is a schematic diagram illustrating another scenario to which the embodiments of this application apply;

[0077] Figure 7A A flowchart illustrating another embodiment of the channel access method provided in this application;

[0078] Figure 7BA flowchart illustrating another embodiment of the channel access method provided in this application;

[0079] Figure 7C A flowchart illustrating another embodiment of the channel access method provided in this application;

[0080] Figure 8 This is a schematic diagram illustrating another scenario to which the embodiments of this application apply;

[0081] Figure 9A Another timing diagram illustrating the shared remaining NAV duration provided in this application embodiment;

[0082] Figure 9B Another timing diagram illustrating the shared remaining NAV duration provided in this application embodiment;

[0083] Figure 10A Another timing diagram illustrating the shared remaining NAV duration provided in this application embodiment;

[0084] Figure 10B Another timing diagram illustrating the shared remaining NAV duration provided in this application embodiment;

[0085] Figure 11 A flowchart illustrating another embodiment of the channel access method provided in this application;

[0086] Figure 12 A schematic diagram of a channel access device provided in an embodiment of this application;

[0087] Figure 13 This is another structural schematic diagram of the channel access device provided in the embodiments of this application. Detailed Implementation

[0088] In IEEE 802.11 wireless local area networks (WLANs), two access mechanisms are defined: Distributed Coordination Function (DCF) and Point Coordination Function (PCF). DCF provides distributed access based on a contention mechanism, where multiple nodes compete for channel access. PCF, on the other hand, provides polling-based access with centralized control, based on a contention-free mechanism. It should be understood that the term "DCF mode" below refers to nodes accessing the channel based on a contention mechanism.

[0089] Figure 1A This is a schematic diagram illustrating a scenario to which an embodiment of this application applies. (Refer to...) Figure 1AThis scenario includes at least two terminal devices, such as a mobile phone and a tablet. Figure 1A This example illustrates the scenario where a mobile phone and a tablet are operating on the same channel (e.g., 5G band channel 36, or Ch36 channel). When the mobile phone and tablet are successfully connected, the mobile phone can project its screen onto the tablet. For instance, the mobile phone sends projection data to the tablet, and the tablet displays the same screen as the mobile phone based on this data, thus achieving projection. During the projection process, the mobile phone and tablet can compete for access to the channel to transmit data, enabling interaction between the two devices.

[0090] For example, when a mobile phone and tablet successfully connect, in DCF mode, the mobile phone monitors the status of channel 36 based on the carrier sense multiple access with collision avoidance (CSMA / CA) contention mechanism. If the mobile phone determines that channel 36 is idle for a preset duration, it enters a backoff state. This backoff state can be understood as follows: the mobile phone stores a backoff duration; in response to detecting that channel 36 is idle for the preset duration, the mobile phone can start counting down the backoff duration. If channel 36 is still idle when the backoff duration countdown ends, the mobile phone can send screen projection data to the tablet on channel 36.

[0091] In this scenario, after receiving screen projection data from a mobile phone on channel 36, the tablet computer can compete for access to channel 36 to send a transmission control protocol acknowledge character (TCP ACK) to the mobile phone. It should be understood that the TCP ACK involved in this embodiment is a data frame, not a control frame. The tablet computer needs to compete for channel access to send a TCP ACK to the mobile phone. The process of the tablet computer competing for access to channel 36 can be as follows: The tablet computer listens to the status of channel 36 based on the CSMA / CA contention mechanism. If the tablet computer determines that channel 36 is idle for a preset time, it enters a backoff state. If the tablet computer is still listening on channel 36 when the backoff time countdown ends, it can send a TCP ACK to the mobile phone on channel 36. In this way, the mobile phone and tablet computer complete one interaction.

[0092] It should be noted that when a phone screen is projected onto a tablet, and the user operates the tablet, the tablet can send reverse touch data to the phone based on the user's actions. This reverse touch data instructs the phone to perform corresponding operations based on the user's actions; details will not be elaborated here. For the tablet to send reverse touch data to the phone, it must first compete for access to channel 36 to send the data. Refer to the description of the tablet sending TCP ACK feedback to the phone above.

[0093] The method for mobile phones and tablets to monitor whether channel 36 is idle can be found in the relevant description in the IEEE 802.11 protocol, and will not be elaborated here.

[0094] Taking a mobile phone as an example, after the mobile phone competes for access to channel 36, it can send screen projection data to the tablet in the form of data packets. The mobile phone can use virtual carrier sensing (VCS) to set the network allocation vector (NAV) in the Duration field of the MAC frame header of the data packet. The NAV can be understood as a timer, representing the length of time the mobile phone will occupy the channel. The tablet can determine the mobile phone's NAV based on the Duration field in the MAC frame header. Upon receiving the first data packet containing the NAV from the mobile phone, the tablet can start counting down the NAV. Before the NAV value reaches 0, the tablet considers channel 36 busy and will not compete for access. Only when the NAV value reaches 0 does the tablet begin competing for access to channel 36. In other words, when the tablet receives screen projection data from the mobile phone on channel 36, and the NAV value of the mobile phone reaches 0, the tablet can compete for access to channel 36 to send back TCP ACK or reverse touch data to the mobile phone on channel 36. It should be understood that the NAV duration and NAV value in the following embodiments have the same meaning as NAV representation, that is, the NAV of a node.

[0095] Taking a mobile phone as an example, if a mobile phone fails to transmit data on channel 36 after competing for channel access, it considers the channel congested. In the current IEEE 802.11 protocol, the mobile phone will double the backoff time. However, factors such as hidden terminals and channel errors can also cause data transmission failures on channel 36, doubling the backoff time and causing unnecessary channel access delay. If the mobile phone successfully transmits data on channel 36, it considers the channel idle, and in the current IEEE 802.11 protocol, the mobile phone will reduce the backoff time, easily leading to contention. Current methods for nodes to compete for channel access are difficult and time-consuming. A node can be understood as a device competing for channel access, such as... Figure 1A Mobile phones or tablets.

[0096] For example, refer to Figure 1B In one embodiment, a mobile phone is connected to a tablet, and a smart screen is also connected to the tablet. Both the mobile phone and the smart screen can transmit data with the tablet. Assuming the mobile phone's backoff time is 10ms and the smart screen's backoff time is 20ms, when the mobile phone competes for access to channel 36, it can send data to the tablet on channel 36. If the smart screen is far from the mobile phone and cannot detect the mobile phone sending data to the tablet on channel 36, it assumes channel 36 is idle. Thus, the smart screen is a hidden terminal relative to the mobile phone. Consequently, the smart screen also sends data to the tablet on channel 36, causing data collisions between the mobile phone and the smart screen on channel 36, resulting in data transmission failure between the two devices.

[0097] According to the current IEEE 802.11 protocol, because both the mobile phone and the smart screen fail to transmit data on channel 36, the contention window (CW) of both devices doubles after the data collision, increasing the difficulty for them to compete for channel access. Since the backoff time is directly proportional to the contention window (for example, backoff time = rand(0,1) × CW, where rand(0,1) represents any value between 0 and 1), the backoff time of both the mobile phone and the smart screen increases accordingly as the contention window increases. The following explanation uses backoff time as an example. For instance, if the backoff time of the mobile phone is adjusted to 20ms and the backoff time of the smart screen is adjusted to 40ms, then when the mobile phone and the smart screen compete for access to channel 36, the mobile phone, with its smaller backoff time (or contention window), can compete for access to channel 36 with priority over the smart screen. Because smart screens are hidden terminals compared to mobile phones, data transmission on smart screens often fails, increasing the contention window until it reaches a preset maximum value, making it even more difficult for smart screens to compete for access to channel 36. In contrast, once a mobile phone successfully competes for access to channel 36 and transmits data, it can reduce its contention window. This reduction in the contention window enhances the phone's ability to compete for channel access. A phone with a strong channel access capability is more likely to maintain access, continuously reducing its contention window until it reaches a preset minimum value, making it difficult for other nodes to access the channel.

[0098] Because nodes set their NAV (Network Access Value) after competing for channel access, the applicant discovered that to ensure successful data transmission, nodes typically set a NAV longer than the "time required for data transmission" to avoid data transmission failures caused by network jitter and transmission latency. Given the current difficulties and long latency associated with node channel access in the IEEE 802.11 protocol, the applicant considered that if a node competing for channel access has remaining NAV after successfully transmitting data, it could share this remaining NAV with other nodes competing for channel access. This would eliminate the need for other nodes to compete for channel access, reducing the difficulty and latency of channel access. Accordingly, this application provides a channel access method whereby the first node competing for channel access, after completing data transmission, can share its remaining NAV with other nodes, allowing them to transmit data on the channel during that remaining NAV. This not only improves channel utilization but also reduces the difficulty and latency of channel access.

[0099] In one embodiment, the nodes in this application may include, but are not limited to, access points (APs), station (STA) devices, or servers. APs may include, but are not limited to, routers, customer premises equipment (CPEs), etc. STA devices may include, but are not limited to, mobile phones, tablets, laptops, wearable devices, speakers, and other terminal devices. Optionally, STA devices may also be personal digital assistants (PDAs), handheld devices with wireless communication capabilities, computing devices, virtual reality (VR) terminal devices, drones, augmented reality (AR) terminal devices, smart devices in the home, etc. The form of the nodes is not limited in this application embodiment.

[0100] The channel access method provided in this application will be described below with reference to specific embodiments. These embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0101] Figure 2A This is a schematic flowchart of one embodiment of the channel access method provided in this application. (Refer to...) Figure 2A The channel access method provided in this application embodiment may include:

[0102] S201, the first node sends the first data to the second node on the channel.

[0103] The first node and the second node have established a connection, and the first node and the second node can be regarded as peer nodes, such as Figure 1A In this application, a mobile phone and a smart screen are used, with the mobile phone serving as the first node and the smart screen as the second node. This embodiment focuses on the first node already accessing the channel. In one embodiment, the first node can compete for channel access according to the DCF mode in the IEEE 802.11 protocol. Alternatively, in another embodiment, the first node can access the channel based on the remaining NAV duration shared by other nodes, as described below in the section on "Second Nodes Sharing the First Remaining NAV Duration to Access the Channel." This application does not limit the method by which the first node accesses the channel; the following embodiment uses the example of the first node competing for channel access.

[0104] Reference Figure 3The first node, competing for access to the channel, can wait for one distributed inter-frame spacing (DIFS) before handshaking with the peer node (i.e., the second node) to avoid collisions. For example, the first node can send a ready-to-send (RTS) frame to the second node to indicate that it is about to send first data. Upon receiving the RTS frame, the second node can, after one short inter-frame spacing (SIFS), send a clear-to-send (CTS) frame to the first node, informing it that the second node is ready to receive the first data. Upon receiving the CTS frame, the first node can send the first data to the second node on the channel after one SIFS. It should be understood that the third node in the following timing diagram represents another node competing for the channel.

[0105] Taking the sending of projection data from the first node to the second node as an example, the first node can split the projection data, encapsulate it in multiple data packets, and send these multiple data packets sequentially to the second node on the channel. It should be understood that the channel described below is the same channel used by the first node to send the data packets.

[0106] After the first node competes for access to the channel, it can set its NAV duration. For example, the first node can set its NAV duration based on the size of the first data to be sent. For instance, if the first node needs to send two data packets, requiring 10ms, it can set the NAV duration to 12ms to ensure successful packet transmission. In one embodiment, the first node can set its NAV duration based on the size of the first data to be sent and the time required for the second node to send a TCP ACK. For example, if the first node needs to send two data packets, requiring 10ms, and the second node needs to send two TCP ACKs, requiring 2ms, then the first node can set the NAV duration to 15ms to ensure successful packet transmission.

[0107] For example, refer to Figure 3After the first node sets its NAV duration, it can carry the NAV duration in the RTS frame, as shown in the diagram as NAV(RTS). The NAV value decreases continuously over time. When the second node sends a CTS frame back to the first node, the first node still has NAV(CTS) remaining. It should be understood that the first node will also carry its remaining NAV duration in the MAC frame header of subsequent data packets sent to the second node. Therefore, the second node can obtain the remaining NAV duration by parsing the data packets. It is conceivable that, since the first node's NAV duration is represented by the Duration field in the MAC frame header, a third node on the same channel as the first node can also obtain the first node's remaining NAV duration by parsing the MAC layer of data packets from the first node.

[0108] S202, if the first node has a first remaining NAV duration on the channel, the first node sends NAV sharing information to the second node on the channel, and the NAV sharing information instructs the second node to send data on the channel.

[0109] When a first node is about to complete transmitting the first data, or when it has completed transmitting the first data, if the first node has a first remaining NAV duration on the channel, the first node can send NAV sharing information to the second node on the channel. This NAV sharing information instructs the second node to transmit data on the channel. In one embodiment, the first node can carry the NAV sharing information in the last data packet it sends to the second node. In another embodiment, the first node can send an Aid frame to the second node after sending the last data packet; the Aid frame may include the NAV sharing information. The following describes these two methods for the first node to send NAV sharing information:

[0110] The first method involves the first node carrying NAV sharing information in the last data packet it sends to the second node. Figure 3 This shows the first node sending a last data packet to the second node. This last data packet may carry NAV shared information. It should be understood that... Figure 2A S202 illustrates this using the example of the first node carrying NAV shared information in the last data packet sent to the second node. For example, refer to... Figure 3 The first node can add an end flag to the reserve field of the data portion of the last data packet, or add an end flag to the reserve field of the frame header portion of the last data packet to indicate that the first node has completed the first data transmission, and the second node can then transmit data on the channel.

[0111] The second method: The first node sends an AID frame to the second node. In this implementation, refer to... Figure 4 The first node can send the last data packet to the second node, and after an interval of one SIFS, send an Aid frame to the second node on the channel. The Aid frame contains NAV sharing information. In one embodiment, the NAV sharing information may include: the first node's first remaining NAV duration and / or an identifier indicating the completion of data packet transmission, such as an end flag.

[0112] In one embodiment, when the NAV sharing information may include: the first remaining NAV duration of the first node and an identifier for indicating the completion of data packet transmission, such as an end flag, the second node may determine that the first data transmission of the first node is complete based on the end flag in the NAV sharing information, and may obtain the first remaining NAV duration of the first node on the channel based on the first remaining NAV duration in the NAV sharing information.

[0113] In one embodiment, when the NAV sharing information may include the first remaining NAV duration of the first node, the second node can not only obtain the first remaining NAV duration of the first node on the channel, but also determine, based on the first remaining NAV duration, that the second node can access the channel to send data on the channel.

[0114] In one embodiment, when the NAV sharing information may include an identifier indicating the completion of data packet transmission, such as an end flag, the second node can determine that the first node's first data transmission is complete based on the end flag in the NAV sharing information. Furthermore, because the second node can obtain the first node's NAV based on data packets from the first node and count down the NAV, the second node can obtain the first node's first remaining NAV duration when it receives the NAV sharing information, as described in the relevant section of S201 above.

[0115] In one embodiment, the format of the AID frame can be as shown in Table 1 below:

[0116] Table 1

[0117]

[0118] In an AID frame, besides the Frame Body and Frame Check Sequence (FCS), the rest is the MAC frame header. The Frame Control field, which can occupy multiple bits, carries information such as the protocol version and frame subtype. The Duration field, which can occupy multiple bits, carries channel occupancy time information, such as NAV. Address1 (DA) represents the destination address, Address2 (SA) represents the source address, and Address3 (BSSID) represents the Basic Service Set Identifier. The Sequence Control field, which can occupy multiple bits, carries the packet sequence number information. The Frame Body represents the payload and may contain the first remaining NAV duration. The FCS, commonly known as the frame trailer, is the tail field of the protocol data unit (frame) at the data link layer of a computer network; it is a 2-byte Cyclic Redundancy Check (CRC) code.

[0119] In one embodiment, the first node can determine whether to send NAV sharing information to the second node based on a first remaining NAV duration. Specifically, if the first remaining NAV duration is very small and insufficient to complete the transmission of any data, the first node may not send NAV sharing information to the second node; if the first remaining NAV duration is greater than or equal to a first preset duration, the first node may send NAV sharing information to the second node.

[0120] S203, the second node responds to the NAV shared information and determines whether the transmission of the second data of the second node can be completed within the first remaining NAV duration; if yes, execute S204, if no, execute S205.

[0121] Based on the relevant description in S201 above, the second node can obtain the remaining NAV duration of the first node. Accordingly, when the second node receives the NAV sharing information from the first node, it can determine whether the second node can complete the transmission of the second data within the first remaining NAV duration.

[0122] For example, the first node sends a data packet for screen projection to the second node. This second data packet can be a TCP ACK. The second node needs to send a TCP ACK back to the first node. The second node then determines whether the TCP ACK transmission can be completed within the first remaining NAV duration. Specifically, the second node determines whether the TCP ACK transmission time is less than or equal to the first remaining NAV duration. If the TCP ACK transmission time is less than or equal to the first remaining NAV duration, the second node determines that the TCP ACK transmission can be completed within the first remaining NAV duration. If the TCP ACK transmission time is greater than the first remaining NAV duration, the second node determines that the TCP ACK transmission cannot be completed within the first remaining NAV duration.

[0123] In one embodiment, the second data can be understood as the smallest data unit that the second node supports transmitting. This smallest data unit can be a data packet split from the second data, or a fragment of the second data. In this embodiment, taking a data packet as the smallest data unit, when the second node receives NAV sharing information from the first node, it can determine whether it can complete the transmission of a data packet of the second data within the first remaining NAV duration. If it can complete the transmission of a data packet of the second data within the first remaining NAV duration, the second node can transmit a data packet of the second data on the channel.

[0124] In this embodiment, the second node detects whether it can complete the transmission of a minimum data unit within the first remaining NAV duration, which can improve channel utilization and complete data transmission within the limited remaining NAV duration. It should be understood that the transmission of other data packets in the second data can be: transmitted after the second node competes for access to the channel, or transmitted by the second node using the first node's next shared NAV duration, which can effectively utilize the first node's remaining NAV duration and improve channel utilization.

[0125] S204, the second node sends the second data to the first node on the channel.

[0126] For example, the second data can be a TCP ACK, see reference. Figure 3 The second node can send a TCP ACK back to the first node on the channel after receiving the last data packet and after an interval of one SIFS. (See reference...) Figure 4 The second node can send a TCP ACK back to the first node on the channel after receiving the aid frame from the first node and after an interval of one SIFS.

[0127] In the current IEEE 802.11 protocol, a second node, upon receiving the last data packet from the first node, can compete for access to the channel to send a TCP ACK to the first node. This channel competition is difficult and time-consuming for the second node. However, in this embodiment, the second node can directly send a TCP ACK to the first node within the first remaining NAV duration. This eliminates the need for channel competition, solving the problems of difficulty and time delay. Furthermore, because the first node's NAV duration has not yet decreased to zero, other nodes (excluding the first and second nodes) will not compete for access. The second node can then send data within the first remaining NAV duration without data packet collision failure, resulting in a high data transmission success rate.

[0128] S205, when the NAV value of the first node decreases to 0, the first node and the second node compete for access to the channel.

[0129] Because the second node cannot complete the transmission of the second data within the remaining NAV duration, it can choose not to respond upon receiving the NAV sharing information. Instead, it can count down the first node's NAV. When the first node's NAV value decreases to 0, after a DIFS (Distribution-First-Side Query), the first and second nodes can compete for access to the channel. It should be understood that when the first node's NAV value decreases to 0, after a DIFS, the first node, the second node, and other nodes requiring channel access can all compete for access to the channel.

[0130] As described above, the second node can transmit the second data on the channel within the remaining NAV duration of the first node. Thus, in scenarios where a mobile phone projects its screen to a smart screen, after the mobile phone competes for channel access, a longer NAV duration can be set. This allows the smart screen to utilize the remaining NAV duration of the mobile phone to send data to the smart screen and then send a TCP ACK response back to the mobile phone on the channel, thereby reducing projection latency and minimizing stuttering issues during projection.

[0131] It should be understood that the channel access method provided in this application is not only applicable to screen projection scenarios, but can also be applied to scenarios such as data transmission between AP and STA devices, peer-to-peer (P2P) data transmission, transmission control protocol (TCP) streaming scenarios, and data transmission between two nodes on the same island in a device-to-device (D2D) communication. It should be understood that a TCP streaming scenario can be understood as a scenario in which TCP streams are transmitted between any two nodes in a TCP communication scenario. In one embodiment, D2D can be, but is not limited to, a traditional D2D scenario, or a Huawei device-to-device (HiD2D) scenario, etc. The following description uses HiD2D as an example of D2D.

[0132] In this embodiment, the first node can share its remaining NAV duration with the second node after completing or nearing the completion of data transmission. This allows the second node to use the remaining NAV duration to send second data to the first node on the channel. This avoids channel idle time and improves channel utilization. Furthermore, the second node does not need to compete for channel access; it directly sends second data within the remaining NAV duration of the first node, improving its channel access capability, reducing channel contention and collisions, lowering access latency, and increasing throughput. Additionally, because the first node's NAV duration has not yet decreased to zero, other nodes (excluding the first and second nodes) will not compete for channel access, resulting in a high success rate for the second node sending data within the remaining NAV duration.

[0133] In one embodiment, after the first node receives a TCP ACK from the second node, if the first node detects that it still has a second remaining NAV duration on the channel, the first node can continue to share the second remaining NAV duration with other nodes. The method of sharing with other nodes can be referred to below. Figure 7A Related descriptions.

[0134] The method in this embodiment can be applied to scenarios where a mobile phone can simultaneously project its screen to two devices, such as a smart screen and a tablet computer. Figure 5A Taking the example of a mobile phone sending an AID frame to a smart screen, the mobile phone can share its remaining NAV (Network Access Validation) time with the smart screen. After the smart screen sends a TCP ACK on the channel, the mobile phone detects that it still has a second remaining NAV time on the channel. The mobile phone can then continue sending screen projection data to the tablet and send NAV sharing information to the tablet via an AID frame. This allows the tablet to send a TCP ACK to the mobile phone on the channel within the remaining NAV time. In this way, the mobile phone can share its remaining NAV time with both devices, further reducing screen projection latency. It should be understood that... Figure 5A The other nodes in the following timing diagram are: nodes that need to access the channel where the first node is located, in addition to the first node and the second node.

[0135] In one embodiment, as in S204 of the above embodiment, after the second node sends a TCP ACK to the first node on the channel, if the second node still needs to send reverse touch data to the first node, refer to... Figure 2B S204 may also include:

[0136] S206: Obtain the second remaining NAV duration of the first node, and determine whether the transmission of the third data of the second node can be completed within the second remaining NAV duration; if yes, execute S207; if no, return to execute the above S205.

[0137] The third data differs from the second data. For example, the second data might be a TCP ACK, while the third data is reverse touch data. For instance, if the second node needs to send reverse touch data back to the first node after sending a TCP ACK, the second node can obtain the second remaining NAV duration of the first node after sending the TCP ACK. This allows it to determine whether the transmission of the reverse touch data can be completed within the second remaining NAV duration. In other words, the second node determines whether the duration of the reverse touch data transmission plus the duration of one SIFS is less than or equal to the first remaining NAV duration, as described above regarding TCP ACK.

[0138] In one embodiment, the third data can be understood as the smallest data unit that the third node supports sending, such as a data packet, which can be referred to in the relevant description of the second data above.

[0139] S207, the second node sends third data to the first node on the channel.

[0140] For example, taking the sending of an AID frame from the first node to the second node as an example, refer to... Figure 5B The second node can send a TCP ACK to the first node, and after an interval of one SIFS, send the reverse touch data on the channel. It should be understood that the second node can split the reverse touch data, encapsulate it in multiple data packets, and send them to the first node. Figure 5B The image shows the last data packet sent by the second node to the first node. In one embodiment, the reverse touch data can also be encapsulated in a single data packet and transmitted to the first node. Figure 5B The data packet shown is this single data packet.

[0141] In one embodiment, the second node may include an end flag in the last data packet sent to the first node to indicate that the second node's third data transmission is complete. Accordingly, in response to this last data packet, if the first node detects that it still has remaining NAV duration on the channel, it may continue to share the remaining NAV duration with other nodes. The method of sharing with other nodes can be described below. Figure 7A Related descriptions.

[0142] In one embodiment, after the second node sends the last data packet to the first node, if the second node detects that the first node still has remaining NAV duration on the channel, the second node can continue to share the remaining NAV duration with other nodes. The method of sharing with other nodes can be referred to below. Figure 7A Related descriptions.

[0143] In this embodiment, the second node can use the remaining NAV duration of the first node to continuously transmit data multiple times, thereby improving channel utilization. Alternatively, the first node can share its remaining NAV duration with multiple nodes, which also improves channel utilization and reduces the difficulty and latency for nodes to access the channel.

[0144] The above embodiments illustrate that the channel access method provided by this application can be applied to a scenario where "the first node shares its remaining NAV duration with the peer node." In one embodiment, the channel access method provided by this application can also be applied to a scenario where "the first node shares its remaining NAV duration with the third node." Here, the third node is not the peer node of the first node, but a node that requests access to the same channel as the first node. The following will use a scenario as an example to elaborate on the channel access method provided by this application.

[0145] Figure 6 This is a schematic diagram illustrating another scenario to which the embodiments of this application apply. (Refer to...) Figure 6 This scenario can include one access point (AP) and multiple standby devices (STAs). The AP can be a router, and the STAs can be smart screens, point-of-sales (POS) machines, etc., in a shopping mall. Because screen projection services have a higher priority, smart screens have a stronger ability to compete for access channels compared to POS machines. Therefore, in this scenario, POS machines are prone to failing to compete for access channels, resulting in problems such as POS machines being unable to process card transactions. To solve this problem, the channel access method provided in this application embodiment allows the AP to manage multiple STAs connected to the AP and share the AP's remaining NAV duration with STAs that have been unable to compete for access channels for an extended period. This allows STAs that have been unable to compete for access channels for a long time, such as POS machines, to access the channel and process card transactions normally. See details below. Figure 7A The relevant description in the document.

[0146] Figure 7A This is a schematic flowchart of another embodiment of the channel access method provided in this application. (Refer to...) Figure 7A The channel access method provided in this application embodiment may include:

[0147] S701, the first node sends the first data to the second node on the channel.

[0148] S701 can be referred to the relevant description in S201. For example, in... Figure 6 In the scenario shown, the first node can be an access point (AP), and the second node can be any STA device connected to the AP. For example, in a video conferencing scenario, the first node can be a router, and the second node can be a device such as a tablet or smart screen. The first data sent by the first node to the second node can be video conferencing data.

[0149] S702, if the first node has a first remaining NAV duration on the channel, the first node sends NAV sharing information to the third node on the channel, and the NAV sharing information instructs the third node to send data on the channel.

[0150] The peer node of the first node is the second node. After the first node completes sending a data packet to the second node, if the first node has a first remaining NAV duration on the channel, the first node can send NAV sharing information to the third node on the channel. This NAV sharing information instructs the third node to send data on the channel.

[0151] When the first node shares the first remaining NAV duration with the third node, the third node can be determined first. In one embodiment, the third node can be a node connected to the first node but which has not accessed the channel for an extended period. "Not accessing the channel for an extended period" can be understood as: the duration of the node's inactivity is greater than or equal to a preset duration. Accordingly, the first node can designate a node that has not accessed the channel for an extended period as the third node. In one embodiment, the third node can be the node with the highest service priority.

[0152] For example, with Figure 6 Taking a scenario as an example, the AP is connected to devices such as POS machines and smart screens. In one embodiment, the AP can detect whether the POS machine, smart screen, or other devices connected to the AP have not accessed the channel for an extended period. If so, the AP can identify the devices that have not accessed the channel for a long time as third nodes. It should be understood that devices that have accessed the channel can send data packets on the channel. The AP can parse the MAC layer of the data packets to obtain the devices occupying the channel, and thus can also obtain the devices that have not accessed the channel for a long time, in order to determine the third nodes that have not accessed the channel for a long time.

[0153] In one embodiment, the AP can determine the service priority of devices such as POS machines and smart screens based on historical interaction data with them, and then designate the device with the highest service priority as the third node. For example, in the current IEEE 802.11 protocol's Quality of Service (QoS) mechanism, the priority of service queues from highest to lowest is: voice (video, VI) queue, video (voice, VO) queue, best effort (BE) queue, and background (BK) queue. Accordingly, the AP can determine the service priority of devices such as POS machines and smart screens based on the service queue in which historical interaction data with them belongs, thus identifying the third node with the highest service priority.

[0154] Or, refer to Figure 8 Nodes A, B, C, and D are nodes in an island within HiD2D. Node A is connected to Node B, and Node C is connected to Node D. Node A is not connected to Node C or Node D. However, because nodes A, B, C, and D form an island within HiD2D, they operate on the same channel, such as channel 36. It should be understood that nodes A, B, C, and D can share their connection information within the HiD2D social channel. This connection information can include service channel, communication time slot, and service type. Thus, a node located on an island can obtain the service type of other nodes on that island through the social channel. Furthermore, a node can also obtain the MAC address of other nodes on that island based on the Media Access Control (MAC) address used to send the connection information. In other words, a node located on an island can obtain information such as the service type and MAC address of other nodes on that island through the social channel.

[0155] Thus, with Figure 8 Taking the scenario as an example, in one embodiment, on the same island, a node that accesses the channel can send data packets on the channel. Node A, located on an island, can parse the MAC layer of the data packet to obtain the MAC address of the device occupying the channel. Then, based on the MAC address of the node occupying the channel, it can obtain the device that has not accessed the channel for a long time, so as to determine the third node that has not accessed the channel for a long time.

[0156] In one embodiment, node A can obtain the service type of each node in the island through the social channel, and then node A can determine the third node based on the service type of each node. For example, node A can choose a node with a high service priority as the third node. If node C's service type is screen mirroring, which has a high priority, then node A can choose node C as the third node. Figure 8 In this context, node D is considered the peer node of node C. Node A can be viewed as the first node, and node B as the second node.

[0157] For example, referring to Table 2, the priority of a business can be represented as shown in Table 2, with 0 to 5 indicating that the priority of a business gradually decreases:

[0158] Table 2

[0159]

[0160]

[0161] It should be understood that fps represents the number of frames transmitted per second.

[0162] In this embodiment, because the third node is not the peer node of the first node, in one embodiment, refer to Figure 9A The first node sends the last data packet to the second node, and after an interval of one SIFS, it sends an aid frame to the third node on the channel. The aid frame contains NAV sharing information. NAV sharing information may include: the remaining NAV duration of the first node and / or an identifier indicating the completion of data packet transmission, such as an end flag. The format of the aid frame can be referred to the relevant description in the above embodiments. It should be understood that, for the above... Figure 8 In the scenario shown, the AID frame sent by the first node to the third node can be a management frame.

[0163] In one embodiment, reference is made to... Figure 9B The first node can respond by sending the last data packet to the second node and receiving a TCP ACK from the second node. After an interval of one SIFS, it can send an AID frame to the third node on the channel.

[0164] As described above, the first node can select a third node from the non-peer nodes and then send NAV sharing information to the third node.

[0165] S703, the third node responds to the NAV shared information and determines whether the transmission of the second data of the third node can be completed within the first remaining NAV duration; if yes, execute S704, if no, execute S705.

[0166] In one embodiment, the NAV sharing information may include the first remaining NAV duration of the first node, thereby enabling the third node to obtain the first remaining NAV duration of the first node. In another embodiment, because the third node is capable of parsing the MAC frames of data packets from the first node, the third node can obtain the first remaining NAV duration of the first node, as described in the relevant section of S201 above.

[0167] When the third node receives the NAV sharing information from the first node, it can determine whether the transmission of the second data of the third node can be completed within the first remaining NAV duration. This process can refer to the relevant description of the second node in S203 above. For example, taking the fourth node as the peer node of the third node, and the third node being a POS machine and the fourth node being a mobile phone, the second data can be: a card swipe request sent by the POS machine to the mobile phone. For example, taking the fourth node as the peer node of the third node, and the third node being a mobile phone and the fourth node being a smart screen, the second data can be: screen projection data sent by the mobile phone to the smart screen.

[0168] In one embodiment, the third node determines whether the transmission of its second data can be completed within the first remaining NAV duration of the first node. This means determining whether the transmission of the second data and the feedback from the fourth node can be completed within the first remaining NAV duration. For example, when a mobile phone sends projection data to a smart screen, the phone needs to determine whether the projection data transmission can be completed within the first remaining NAV duration and receive a TCP ACK from the smart screen.

[0169] Specifically, if the sum of the "transmission duration of the second data" and the "feedback duration of the fourth node" is less than or equal to the first remaining NAV duration, then the third node is determined to be able to complete the transmission of the second data and the feedback from the fourth node. If the sum of the "transmission duration of the second data" and the "feedback duration of the fourth node" is greater than the first remaining NAV duration, then the third node is determined to be unable to complete the transmission of the second data and the feedback from the fourth node.

[0170] S704, the third node sends the second data to the fourth node on the channel.

[0171] Reference Figure 9A and Figure 9B The third node can send the second data to the fourth node on the channel within the first remaining NAV duration. Figure 9A and Figure 9B The examples used here are of a third node sending the last data packet to a fourth node. For instance, a POS machine might send a card swipe request to a mobile phone, or a mobile phone might send screen projection data to a smart screen. Thus, refer to... Figure 6In the scenario shown, the AP can share its remaining NAV duration with the POS machine, allowing the POS machine to access the channel without contention and complete transactions such as card swiping. This enables nodes that have not been able to compete for channel access for a long time to successfully send data on the channel.

[0172] In one embodiment, if the third node determines that it can complete the transmission of its second data and the feedback from the fourth node within the first remaining NAV duration, then after sending the second data to the fourth node, the third node can share the first node's second remaining NAV duration with the fourth node, allowing the fourth node to feed back data to the third node on the channel within the second remaining NAV duration. Figure 9A and Figure 9B As shown, taking the example of the fourth node sending a TCP ACK to the third node within the second remaining NAV duration, this process can refer to the relevant descriptions above regarding "the first node sharing the first remaining NAV duration with the second node" or "the first node sharing the first remaining NAV duration with the third node".

[0173] by Figure 9B For example, the fourth node can send data back to the third node within the second remaining NAV period. For instance, a smart screen can send a TCP ACK back to a mobile phone.

[0174] S705, when the NAV value of the first node decreases to 0, the first node, the second node, and the third node compete for access to the channel.

[0175] S705 can be referred to in the relevant description of S205 above, and will not be repeated here.

[0176] The channel access method in this application embodiment can be applied to, but is not limited to, scenarios where an AP is connected to multiple STA devices, or scenarios where the same island exists in HiD2D.

[0177] In this embodiment, the first node can share its remaining NAV duration with a third node that has been unable to compete for the channel for an extended period, or a third node with a high priority for its service type. This allows the third node to access the channel and execute its own services, improving channel utilization and increasing the third node's channel access capability. This embodiment also achieves the same technical effects as the embodiments described above, which can be referred to in the relevant descriptions.

[0178] exist Figure 7A In the illustrated embodiment, in one possible scenario, if the first node shares the first remaining NAV duration with a third node that has not accessed the channel for a long time, and the third node has no data to send, then in this scenario, refer to Figure 7B The above S703-S705 can be replaced by S703A-S704A.

[0179] In S703A, the third node feeds back first information to the first node, and the first information indicates that the third node does not need to access the channel.

[0180] Since the third node has no data to transmit on the channel, it can send back first information to the first node. This first information indicates that the third node does not need to access the channel, thus allowing the first node to share its remaining NAV duration with other nodes. In one embodiment, the first information can be an AID frame, which may include the first node's remaining NAV duration.

[0181] S704A, the first node sends an AID frame to the fifth node.

[0182] In one embodiment, the fifth node is similar to the third node; for example, the fifth node can be a node that has not accessed the channel for a long time, or a node with a high-priority service type. It should be understood that when the fifth node is a node that has not accessed the channel for a long time, the first node can select the node with the longest channel inaccessibility period as the third node, and the node with the second longest channel inaccessibility period as the fifth node. This application embodiment does not limit the method by which the first node selects the fifth node.

[0183] It should be noted that the aid frame may contain NAV sharing information, which indicates the second remaining NAV duration of the first node. The second remaining NAV duration is less than the first remaining NAV duration. The aid frame instructs the fifth node to transmit data on the channel. It should be understood that after the fifth node receives the aid frame from the first node, it can perform S703-S705 as described above, or perform S703A as described above, as can be referred to in the relevant descriptions above.

[0184] In one embodiment, if the first node shares the first remaining NAV duration with a third node that has not accessed the channel for a long time, and if the third node has no data to send, then in this scenario, refer to Figure 7C The above S703-S705 can also be replaced by S703B.

[0185] S703B, the third node sends an AID frame to the fifth node.

[0186] To conserve the remaining NAV time of the first node, when the third node has no data to send, it can bypass the first node and directly send an AID frame to the fifth node, instructing the fifth node to send data on the channel. It should be understood that after receiving the AID frame from the first node, the fifth node can perform steps as described in S703-S705, or steps as described in S703A, as described above.

[0187] In this embodiment of the application, when the first node shares the first remaining NAV duration with the third node, and the third node has no data to send on the channel, the third node can directly share the remaining NAV duration of the first node with the fifth node, or the third node can share the remaining NAV duration of the first node with the fifth node through the first node. Both methods can effectively utilize the remaining NAV duration of the first node and improve the channel utilization rate.

[0188] As described in the above embodiment, the first node can share its remaining NAV duration with the peer node (second node) or a non-peer node (third node).

[0189] In one embodiment, the first node can determine whether to share the first remaining NAV duration with a second or third node based on the first remaining NAV duration. Specifically, if the first remaining NAV duration is greater than or equal to a first preset duration and less than a second preset duration, the amount of data that can be transmitted within the first remaining NAV duration is limited. Since the second node interacting with the first node mostly sends TCP ACKs back to the first node, occupying relatively little time, the first node can share the first remaining NAV duration with the second node. That is, the first node sends NAV sharing information to the second node, causing the second node to send a TCP ACK back to the first channel on the channel, thus completing an interaction between the first and second nodes. The second preset duration is greater than the first preset duration.

[0190] If the first remaining NAV duration is greater than or equal to the second preset duration, then a larger amount of data can be transmitted within the first remaining NAV duration. This is because the third node interacts with the fourth node, and the third node, as the initiator of this interaction, transmits data for a longer duration than the TCP ACK transmission duration. Therefore, the first node can share the first remaining NAV duration with the third node, that is, the first node sends NAV sharing information to the third node, enabling the third node to interact with the fourth node on the channel.

[0191] In this way, the first node can select a target node to share the first remaining NAV duration based on the first remaining NAV duration, which can improve flexibility.

[0192] In one embodiment, if the first remaining NAV duration is greater than or equal to the third preset duration, and the third preset duration is greater than the second preset duration, that is, when the first remaining NAV duration is larger, the first node can share the first remaining NAV duration with the node with higher priority based on the priorities of the second node and the third node, and then share the second remaining NAV duration with the node with lower priority.

[0193] For example, if the second node is the peer node of the first node, the peer node has a higher priority than non-peer nodes, ensuring interaction between the first and second nodes. Thus, the first node can first share its first remaining NAV duration with the second node. After the second node transmits data on the channel, the first node still has a second remaining NAV duration on the channel. The first node (or the second node) can then share this second remaining NAV duration with a third node, as can be seen in the following example. Figure 10A As shown.

[0194] In one embodiment, in an island scenario of HiD2D, the first node can obtain the service type of each slave device in the social channel. The first node can share the first remaining NAV duration with the node with the higher priority of the service type based on the priority of the service types of the second and third nodes, and then share the second remaining NAV duration with the node with the lower priority of the service type.

[0195] For example, if the second node's service type is sending reverse touch data and the third node's service type is screen projection, with screen projection having a higher priority than sending reverse touch data, the first node can share its first remaining NAV duration with the third node. After the third node sends screen projection data on the channel, if the first node still has a second remaining NAV duration on the channel, then the first node (or the third node) can share the second remaining NAV duration with the second node. This can be referenced in the following example. Figure 10B As shown, Figure 10B The example of the third node sharing the remaining NAV duration with the second node will be used to illustrate this.

[0196] In this embodiment of the application, the first node can determine to share the remaining NAV duration of the first node with the second node and / or the third node based on the first remaining NAV duration, so that the second node and / or the third node can send data on the channel, and the first node has high flexibility in sharing the remaining NAV duration.

[0197] In summary, referring to the above embodiments... Figure 11 The channel access method provided in this application embodiment may include:

[0198] S1101, in response to detecting the first remaining NAV duration of the first node, the first node sends NAV sharing information to the target node, the NAV sharing information instructing the target node to send data on the channel.

[0199] The target node can be a second node or a third node. The selection of the target node based on the first remaining NAV duration can be referred to the relevant description in the above embodiments.

[0200] S1102, the target node responds to the NAV shared information and determines whether it can complete the transmission of the target node's second data within the first remaining NAV duration; if yes, execute S1113, if no, execute S1114.

[0201] S1103, the target node sends the second data to the peer node of the target node on the channel.

[0202] It should be understood that when the target node is the second node, the peer node of the target node is the first node. Figure 11 The example below uses the target node as the second node. When the target node is the third node, the peer node of the target node is the fourth node.

[0203] S1104, when the NAV value of the first node decreases to 0, the first node and the target node compete for access to the channel.

[0204] S1101-S1104 can be referred to the relevant descriptions in the above embodiments, and will not be repeated here. It should be understood that when the target node detects that the first node still has a second remaining NAV duration on the channel, it continues to send third data to the peer node of the target node on the channel. Alternatively, it can share the second remaining NAV duration with other nodes, as can be referred to the relevant descriptions in the above embodiments.

[0205] Figure 12 This is a schematic diagram of a channel access device provided in an embodiment of this application. The channel access device can be a first node as described in the above embodiment, or a chip within the first node, etc. (Refer to...) Figure 12 In one embodiment, the channel access device 1200 may include a transceiver module 1201 and a processing module 1202.

[0206] The transceiver module 1201 is configured to: send first data to a second node on a channel, and in response to the existence of a first remaining network allocation vector (NAV) duration on the channel by the first node, send first NAV sharing information to a target node on the channel, wherein the first NAV sharing information instructs the target node to send data on the channel, the target node being either the second node or a third node, the service channel of the third node being the channel, and the third node being different from the second node.

[0207] In one possible implementation, the transceiver module 1201 is specifically configured to: in response to the first node having a first remaining NAV duration on the channel, and the first remaining NAV duration being greater than or equal to a first preset duration, send the first NAV sharing information to the target node on the channel.

[0208] In one possible implementation, when the first remaining NAV duration is greater than or equal to the first preset duration and less than the second preset duration, the target node is the second node; when the first remaining NAV duration is greater than or equal to the second preset duration, the target node is the third node, and the second preset duration is greater than the first preset duration.

[0209] In one possible implementation, the transceiver module 1201 is specifically configured to: send a mutual assistance channel access aid frame to the target node on the channel, wherein the aid frame includes the first NAV sharing information.

[0210] In one possible implementation, the first data consists of at least one data packet, and the first NAV sharing information is carried in the last data packet of the at least one data packet.

[0211] In one possible implementation, the first NAV sharing information includes: the first remaining NAV duration, and / or an identifier indicating the completion of the first data transmission.

[0212] In one possible implementation, the third node is either a node whose uncontested access channel duration is greater than or equal to a preset duration, or the node with the highest service priority.

[0213] In one possible implementation, the transceiver module 1201 is further configured to: when the target node is the second node, in response to receiving second data from the second node and the first node having a second remaining NAV duration on the channel, send second NAV sharing information to other nodes on the channel, the second NAV sharing information instructing the other nodes to send data on the channel; or...

[0214] In response to receiving first information from the target node, and the first node having a second remaining NAV duration on the channel, the target node sends second NAV sharing information to other nodes on the channel, wherein the first information indicates that the target node has no data to be sent.

[0215] In one possible implementation, the processing module 1202 is configured to: set the NAV duration of the first node; and during the NAV duration of the first node, compete with the second node and the third node for access to the channel.

[0216] Figure 13 This is another schematic diagram of the channel access device provided in the embodiments of this application. The channel access device can be a target node as described in the above embodiments, or a chip within the target node, etc. The target node can be a second node or a third node as described in the above embodiments. (Refer to...) Figure 13 In one embodiment, the channel access device 1300 may include a transceiver module 1301 and a processing module 1302.

[0217] The transceiver module 1301 is configured to: receive first network allocation vector (NAV) sharing information from a first node on a channel, wherein the first NAV sharing information instructs the target node to transmit data on the channel, the target node being a second node or a third node, wherein the second node is the peer node of the first node, or the service channel of the third node is the channel and the third node is different from the second node.

[0218] In one possible implementation, the transceiver module 1301 is specifically configured to: receive a mutual assistance channel access aid frame from the first node on the channel, the aid frame including the first NAV sharing information.

[0219] In one possible implementation, if the target node is the second node, the transceiver module 1301 is further configured to: receive first data from the first node on the channel, the first data consisting of at least one data packet, the first NAV sharing information being carried in the last data packet of the at least one data packet.

[0220] In one possible implementation, the first NAV sharing information includes: the first remaining NAV duration of the first node, and / or an identifier indicating the completion of the first data transmission from the first node.

[0221] In one possible implementation, the third node is either a node whose uncontested access channel duration is greater than or equal to a preset duration, or the node with the highest service priority.

[0222] In one possible implementation, the transceiver module 1301 is further configured to: based on the first remaining NAV duration of the first node, if it is determined that the transmission of the second data can be completed within the first remaining NAV duration, then send the second data to the peer node of the target node on the channel.

[0223] In one possible implementation, the transceiver module 1301 is further configured to: in response to the first node having a second remaining NAV duration on the channel and being able to complete the transmission of third data within the second remaining NAV duration, send the third data to the peer node of the target node on the channel.

[0224] In one possible implementation, the second data is the smallest data unit that the target node can send.

[0225] In one possible implementation, the processing module 1302 is configured to: based on the first remaining NAV duration of the first node, if it is determined that the transmission of the second data cannot be completed within the first remaining NAV duration, then when the NAV duration of the first node decreases to 0, compete with the first node for access to the channel, wherein the NAV duration of the first node is set when the first node accesses the channel.

[0226] In one possible implementation, the transceiver module 1301 is further configured to: in response to the target node not having any data to be sent, send first information to the first node, the first information indicating that the target node does not have any data to be sent.

[0227] In one possible implementation, the transceiver module 1301 is further configured to: in response to the target node not having data to be transmitted, send third NAV sharing information to other nodes, the third NAV sharing information instructing the other nodes to transmit data on the channel.

[0228] It should be understood that, in the embodiments of this application Figure 12 The provided channel access device is capable of performing the actions of the first node in the above embodiments. Figure 13 The provided channel access device can perform the actions of the target node in the above embodiments, thereby achieving the same technical effect as the above embodiments, which will not be elaborated here.

[0229] In one embodiment, this application provides an electronic device, which can be the first node, second node, or third node described in the above embodiments. The electronic device may include a processor (e.g., CPU), a memory, and a transceiver. The memory and transceiver may be coupled to the processor electronic device, which controls the transceiver to perform the transmission and reception actions of the electronic device, thereby enabling interaction between the electronic device and the cloud. The memory may include high-speed random-access memory (RAM) or non-volatile memory (NVM), such as at least one disk storage device. The memory may store various instructions for performing various processing functions and implementing the method steps of this application. The transceiver may be integrated into the transceiver unit of the electronic device or may be a separately configured transceiver antenna on the electronic device. In this application embodiment, the memory is used to store computer-executable program code, which includes instructions. When the processor electronic device executes the instructions, the instructions cause the processor electronic device to perform the actions described in the above method embodiments. The implementation principle and technical effects are similar and will not be repeated here. Optionally, the electronic device involved in this application may also include a power supply, a communication bus, and a communication port. The communication bus is used to realize communication connections between components. The aforementioned communication ports are used to enable communication between electronic devices and other peripherals.

[0230] It should be noted that these modules can be one or more integrated circuits configured to implement the above methods, such as one or more application-specific integrated circuits (ASICs), one or more digital signal processors (DSPs), or one or more field-programmable gate arrays (FPGAs). Furthermore, when a module is implemented using processing element scheduler code, the processing element can be a general-purpose processor, such as a central processing unit (CPU) or other processor capable of calling program code. Additionally, these modules can be integrated together to implement a system-on-a-chip (SoC).

[0231] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a semiconductor medium (e.g., a solid-state disk (SSD)).

[0232] The term "multiple" in this article refers to two or more. The term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. Furthermore, the character " / " in this article generally indicates an "or" relationship between the preceding and following related objects; in formulas, the character " / " indicates a "division" relationship between the preceding and following related objects.

[0233] In addition, it should be understood that in the description of this application, the words "first" and "second" are used only for the purpose of distinguishing descriptions and should not be construed as indicating or implying relative importance or order.

[0234] It is understood that the various numerical designations used in the embodiments of this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. In the embodiments of this application, the order of the above-mentioned process numbers does not imply the order of execution; the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

Claims

1. A channel access method, characterized in that, Applied to the first node, the method includes: Send the first data to the second node on the channel; In response to the existence of a first remaining Network Allocation Vector (NAV) duration on the channel, the first node sends first NAV sharing information to the target node on the channel. The first NAV sharing information instructs the target node to send data on the channel. The target node is either the second node or the third node, and the service channel of the third node is the channel. The third node is different from the second node. When the first remaining NAV duration is greater than or equal to a first preset duration and less than a second preset duration, the target node is the second node. When the first remaining NAV duration is greater than or equal to the second preset duration, the target node is the third node, and the second preset duration is greater than the first preset duration. The third node is either a node whose non-contention access channel duration is greater than or equal to the preset duration, or the node with the highest service priority.

2. The method according to claim 1, characterized in that, The step of sending the first NAV sharing information to the target node on the channel includes: A mutual assistance channel access (AID) frame is sent to the target node on the channel, and the AID frame includes the first NAV sharing information.

3. The method according to claim 1, characterized in that, The first data consists of at least one data packet, and the first NAV shared information is carried in the last data packet of the at least one data packet.

4. The method according to any one of claims 1-3, characterized in that, The first NAV sharing information includes: the first remaining NAV duration, and / or an identifier indicating the completion of the first data transmission.

5. The method according to any one of claims 1-3, characterized in that, The method further includes: When the target node is the second node, in response to receiving second data from the second node and the first node having a second remaining NAV duration on the channel, the first node sends second NAV sharing information to other nodes on the channel, the second NAV sharing information instructing the other nodes to send data on the channel; or... In response to receiving first information from the target node, and the first node having a second remaining NAV duration on the channel, the target node sends second NAV sharing information to other nodes on the channel, wherein the first information indicates that the target node has no data to be sent.

6. The method according to any one of claims 1-3, characterized in that, Before sending the first data to the second node on the channel, the method further includes: Set the NAV duration for the first node; When the NAV duration of the first node decreases to 0, it competes with the second node and the third node for access to the channel.

7. A channel access method, characterized in that, Applied to the target node, the method includes: The system receives first network allocation vector (NAV) sharing information from a first node on the channel. The first NAV sharing information instructs the target node to transmit data on the channel. The target node is either a second node or a third node. The second node is the peer node of the first node, or the service channel of the third node is the channel and the third node is different from the second node. When the first node's first remaining NAV duration on the channel is greater than or equal to a first preset duration and less than a second preset duration, the target node is the second node. When the first remaining NAV duration is greater than or equal to the second preset duration, the target node is the third node, and the second preset duration is greater than the first preset duration. The third node is either a node whose non-contention access duration on the channel is greater than or equal to the preset duration, or the node with the highest service priority.

8. The method according to claim 7, characterized in that, The step of receiving the first network allocation vector (NAV) shared information from the first node on the channel includes: A mutual aid channel access (AID) frame from the first node is received on the channel, the AID frame including the first NAV sharing information.

9. The method according to claim 7, characterized in that, If the target node is the second node, the step of receiving the first network allocation vector (NAV) shared information from the first node on the channel further includes: First data is received from the first node on the channel. The first data consists of at least one data packet, and the first NAV sharing information is carried in the last data packet of the at least one data packet.

10. The method according to any one of claims 7-9, characterized in that, The first NAV sharing information includes: the first remaining NAV duration of the first node, and / or an identifier indicating the completion of the first data transmission from the first node.

11. The method according to any one of claims 7-9, characterized in that, After receiving the first network allocation vector (NAV) shared information from the first node on the channel, the process further includes: Based on the first remaining NAV duration of the first node, if it is determined that the transmission of the second data can be completed within the first remaining NAV duration, then the second data is sent to the peer node of the target node on the channel.

12. The method according to claim 11, characterized in that, After sending the second data to the peer node of the target node on the channel, the method further includes: In response to the first node having a second remaining NAV duration on the channel, and being able to complete the transmission of third data within the second remaining NAV duration, the first node sends the third data to the peer node of the target node on the channel.

13. The method according to claim 11, characterized in that, The second data is the smallest data unit that the target node can send.

14. The method according to any one of claims 7-9 and 12, characterized in that, After receiving the first network allocation vector (NAV) shared information from the first node on the channel, the process further includes: Based on the first remaining NAV duration of the first node, if it is determined that the transmission of the second data cannot be completed within the first remaining NAV duration, then when the NAV duration of the first node decreases to 0, it competes with the first node for access to the channel. The NAV duration of the first node is set when the first node accesses the channel.

15. The method according to any one of claims 7-9 and 12, characterized in that, After receiving the first network allocation vector (NAV) shared information from the first node on the channel, the process further includes: In response to the fact that the target node does not have any data to be sent, a first message is sent to the first node, the first message indicating that the target node does not have any data to be sent.

16. The method according to any one of claims 7-9 and 12, characterized in that, After receiving the first network allocation vector (NAV) shared information from the first node on the channel, the process further includes: In response to the fact that the target node has no data to be transmitted, a third NAV sharing information is sent to other nodes, which instructs the other nodes to transmit data on the channel.

17. A channel access device, characterized in that, include: The transceiver module is used for: Send the first data to the second node on the channel; In response to the existence of a first remaining network allocation vector (NAV) duration on the channel, the first node sends first NAV sharing information to the target node on the channel. The first NAV sharing information instructs the target node to send data on the channel. The target node is either the second node or the third node, and the service channel of the third node is the channel. The third node is different from the second node. When the first remaining NAV duration is greater than or equal to the first preset duration and less than the second preset duration, the target node is the second node; when the first remaining NAV duration is greater than or equal to the second preset duration, the target node is the third node, and the second preset duration is greater than the first preset duration. The third node is either a node whose uncontested access channel duration is greater than or equal to a preset duration, or the node with the highest service priority.

18. A channel access device, characterized in that, include: The transceiver module receives first network allocation vector (NAV) sharing information from a first node on the channel. The first NAV sharing information indicates that a target node transmits data on the channel. The target node is either a second node or a third node. The second node is the peer node of the first node, or the service channel of the third node is the channel and the third node is different from the second node. When the first node's first remaining NAV duration on the channel is greater than or equal to the first preset duration and less than the second preset duration, the target node is the second node; when the first remaining NAV duration is greater than or equal to the second preset duration, the target node is the third node, and the second preset duration is greater than the first preset duration. The third node is either a node whose uncontested access channel duration is greater than or equal to a preset duration, or the node with the highest service priority.

19. An electronic device, characterized in that, include: Memory, processor; The processor is configured to couple with the memory, read and execute instructions in the memory to implement the method of any one of claims 1-16.

20. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores computer instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1-16.

21. A computer program product, characterized in that, The computer program product includes computer instructions that, when executed by a computer, cause the computer to perform the method of any one of claims 1-16.

Images