Communication device, communication method, and computer-readable medium

Abstract

The invention provides a communication device, a communication method and a computer readable medium. In an 802.11ax network with an access point, a trigger frame supplies a node with scheduled resource units and random resource units for data uplink communication to the access point. To use the network more efficiently, the access point can design the trigger frame to force the node to send certain categories of data. Resource units can be defined in the trigger frame to be dedicated to small packets or some access category data. Adjusting the time length of the resource units helps limit the type of data that can be transmitted in these resource units. Additionally, using different frequency widths for resource units in the same trigger frame can help reduce padding in the resource units in the case of different traffic types coexisting.

Description

[0001] (This application is a divisional application of the application filed on July 8, 2016, with application number 201680040890.6 and titled "Trigger Frames for Packet-Based Policies Suitable for 802.11 Networks".) Technical Field

[0002] This invention generally relates to wireless communication networks, and more specifically to the random allocation of uplink communication for, for example, OFDMA subchannels (or resource elements) forming a communication composite channel. One application of the method relates to wireless data communication over a wireless communication network using Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA), wherein the network is accessible by multiple node devices. Background Technology

[0003] The IEEE 802.11 MAC standard defines how wireless local area networks (WLANs) must operate at both the physical and media access control (MAC) layers. Typically, the 802.11 MAC (Media Access Control) operating mode implements the well-known Distributed Coordination Function (DCF), which relies on a contention-based mechanism based on the so-called Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) technique.

[0004] The 802.11 Media Access Protocol standard, or operating mode, primarily involves managing communication nodes that wait for the wireless medium to become idle in order to attempt to access that wireless medium.

[0005] The network operating mode defined by the IEEE 802.11ac standard provides very high throughput (VHT) by moving from the 2.4 GHz band, which is considered to be highly susceptible to interference, to the 5 GHz band, thereby enabling the use of a wider 80 MHz frequency contiguous channel, in which two of these frequency contiguous channels can be optionally combined to obtain a 160 MHz channel as the operating frequency band for wireless networks.

[0006] The 802.11ac standard also modifies control frames such as Request-To-Send (RTS) and Clear-To-Send (CTS) frames to allow composite channels with different predefined bandwidths of 20MHz, 40MHz, or 80MHz, where the composite channel consists of one or more consecutive channels within the operating frequency band. A 160MHz composite channel can be a combination of two 80MHz composite channels within the 160MHz operating frequency band. The control frame specifies the channel width (bandwidth) of the target composite channel.

[0007] Therefore, a composite channel comprises a primary channel for a given node to perform an EDCA backoff procedure to access the medium, and at least one secondary channel, for example, 20 MHz. The communicating node uses the primary channel to listen for idle status and can use the secondary channel to extend the primary channel to form a composite channel.

[0008] Channel idle detection is performed using CCA (Clear Channel Assessment), and more specifically, CCA-ED (an abbreviation for CCA-Energy Detection). CCA-ED is the ability of any node to detect non-802.11 energy in the channel and back off data transmission. The ED threshold on which the energy detected on the channel is compared is defined, for example, as 20 dB higher than the minimum sensitivity of the node's PHY layer. If the in-band signal energy exceeds this threshold, CCA remains active until the moderate energy falls below the threshold again.

[0009] Given the tree-like decomposition of the operating frequency band into the basic 20MHz channel, some auxiliary channels are named third-level channels or fourth-level channels.

[0010] In 802.11ac, all possible composite channels for transmission include the primary channel. This is because nodes perform full Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) and Network Allocation Vector (NAV) tracking only on the primary channel. Other channels are assigned as secondary channels, where nodes only have CCA (Free Channel Assessment) capability, i.e., the ability to detect the free or busy status / condition of the secondary channel.

[0011] The problem with using composite channels as defined in 802.11n or 802.11ac (or 802.11ax) is that 802.11n and 802.11ac compatible nodes (i.e., HT nodes, an abbreviation for High Throughput node) and other legacy nodes (i.e., non-HT nodes that are only compatible with, for example, 802.11a / b / g) must coexist in the same wireless network and therefore must share a 20MHz channel.

[0012] To address this issue, the 802.11n and 802.11ac standards provide the ability to replicate control frames (e.g., RTS / CTS frames, CTS-to-Self frames, or ACK frames used to confirm the correct or incorrect reception of transmitted data) in the legacy 802.11a format (referred to as "non-HT"), thereby establishing protection for the requested TXOP across the entire composite channel.

[0013] This applies to any legacy 802.11a node that uses any 20MHz channel included in the composite channel to know about the communication taking place on the 20MHz channel it is using. As a result, it prevents legacy nodes from initiating new transmissions before the current composite channel TXOP authorized to the 802.11n / ac node ends.

[0014] As originally proposed by 802.11n, it provides a copy of the traditional 802.11a or “non-HT” transmission, enabling the simultaneous transmission of two identical 20MHz non-HT control frames on both the primary and secondary channels of the composite channel used.

[0015] For 802.11ac, this method has been extended to allow replication on channels forming a composite channel of 80MHz or 160MHz. In the remainder of this document, “replicated non-HT frame” or “replicated non-HT control frame” or “replicated control frame” means that the node device replicates a given control frame’s conventional or “non-HT” transmission on a 20MHz secondary channel within its (40MHz, 80MHz, or 160MHz) operating band.

[0016] In practice, to request a new TXOP on the composite channel (equal to or greater than 40MHz), the 802.11n / ac node performs an EDCA backoff process on the 20MHz primary channel. In parallel, the 802.11n / ac node performs channel sensing mechanisms such as Clear Channel Assessment (CCA) signal detection on the secondary channel to detect secondary channels that are idle (channel state / condition is "idle") during the PIFS interval before the new TXOP begins (i.e., before the backoff counter expires).

[0017] Recently, the Institute of Electrical and Electronics Engineers (IEEE) officially approved the 802.11ax task group as the successor to 802.11ac. A key objective of the 802.11ax task group is to improve the data speed of wireless communication devices used in densely deployed scenarios.

[0018] Recent developments in the 802.11ax standard aim to optimize the use of composite channels in wireless networks with multiple nodes and access points (APs). In practice, typical content involves significant data volumes, such as those related to real-time interactive high-definition audiovisual content. Furthermore, it is well known that the performance of CSMA / CA used in the IEEE 802.11 standard degrades rapidly with increasing node numbers and traffic volume (i.e., in dense WLAN scenarios).

[0019] As network density increases, the number of large collisions and associated retransmissions increases significantly.

[0020] The problematic situation relates to so-called "small packets" (i.e., MAC packets that inherently suffer significant overhead (regarding the amount of payload data) due to factors such as MAC headers and latency in accessing the wireless medium). The more small packets there are, the greater the loss of network bandwidth due to the corresponding overhead, and consequently, the more collisions and retransmissions are associated with them.

[0021] Furthermore, the problem worsens because even though the overhead due to the MAC header is fixed, latency increases with the number of nodes (as more nodes share the medium for access) and the number of collisions.

[0022] Therefore, established services (or scheduled services managed by the AP) may be damaged by small packets transmitted over the network.

[0023] However, in the Basic Service Set (BSS) consisting of APs and their registered nodes, scheduled services are not the primary services.

[0024] To coordinate nodes together, a new Hybrid Coordination Function (HCF) was introduced, which includes two channel access methods: HCF Controlled Channel Access (HCCA) and Enhanced Distributed Channel Access (EDCA). Both EDCA and HCCA define Service Classes (TCs) to adjust QoS (Quality of Service) support by differentiating and negotiating node service parameters. For example, email can be assigned to a low-priority class, and Voice over Wireless (VoWLAN) can be assigned to a high-priority class.

[0025] Four access categories are defined:

[0026] AC_BK is the lowest priority for background data.

[0027] AC_BE is the next priority level for best-effort data service.

[0028] AC_VI is the priority of the video application, and

[0029] AC_VO is the priority of the voice application.

[0030] Each access category essentially has two service classes as defined in IEEE standard 802.11. In the following documents, service classes and access categories are used interchangeably to specify the same concept.

[0031] These QoS services are inherently unfair. They exacerbate collisions and retransmissions in dense environments such as those addressed by 802.11ax, thus leading to inefficiencies in the wireless medium.

[0032] In this context, multi-user transmission is considered to allow multiple simultaneous transmissions relative to different users in both the downlink and uplink directions. In the uplink, multi-user transmission can be used to reduce the probability of collisions by allowing multiple nodes to transmit simultaneously, and to improve network capacity by making overhead (header, latency, etc.) common to MAC packets.

[0033] To enable such multi-user transmission in practice, it is proposed to divide the licensed 20MHz channel into sub-channels (basic sub-channels, also known as resource units (RUs)), in which multiple users can share these sub-channels in the frequency domain, for example, based on orthogonal frequency division multiple access (OFDMA) technology.

[0034] OFDMA is a multi-user variant of OFDM that emerged as a new key technology to improve the efficiency of wireless networks based on advanced infrastructure. OFDMA combines OFDM at the physical layer with Frequency Division Multiple Access (FDMA) at the MAC layer, allowing multiple subcarriers or tones to be assigned to different nodes to improve concurrency. Adjacent subcarriers often experience the same channel conditions and are therefore grouped into subchannels: OFDMA subchannels or RUs are thus collections of subcarriers or tones.

[0035] As currently envisioned, the granularity of this OFDMA subchannel is finer than the original 20MHz channel bandwidth. Typically, a 2MHz or 5MHz subchannel can be considered as the minimum width, thus defining, for example, nine subchannels or resource units within a single 20MHz channel.

[0036] To support multi-user uplinks (i.e., uplink transmissions to 802.11ax access points (APs) during authorized TxOPs), 802.11ax APs must provide signaling information for legacy nodes (non-802.11ax nodes) to set their NAVs and for 802.11ax nodes to determine the allocation of resource units (RUs), and to be used as a reference time for data transmission synchronization.

[0037] It has been proposed that the AP sends a trigger frame (TF) to the 802.11ax node to trigger uplink communication.

[0038] The IEEE 802.11-15 / 0365 standard proposes that an AP sends a "trigger" frame (TF) to request the transmission of uplink (UL) multi-user (OFDMA) PPDUs from multiple nodes. In response, the nodes send UL MU (OFDMA) PPDUs as an immediate response to the trigger frame. All transmitters can transmit data simultaneously, but use a set of disjoint RUs (i.e., frequencies in the OFDMA scheme) to achieve less interference-prone transmission.

[0039] OFDMA used to provide multi-user transport in 802.11ax requires precise inter-user symbol synchronization to maintain orthogonality between different OFDMA subchannels or RUs.

[0040] In addition, each node transmitting PPDUs on a RU must synchronize the end of its PPDU transmission. Otherwise, if a node terminates its transmission prematurely, the unused RU can be acquired by an OBSS (Overlapping Base Station Subsystem) node, which can then initiate a new transmission.

[0041] This could cause interference with the following block acknowledgments (BAs) sent to the node via the AP.

[0042] This could also interfere with the AP while it is receiving other PPDUs that are in progress.

[0043] To ensure synchronization of PPDU transmissions across nodes, nodes must transmit data on their RUs until the TXOP duration is indicated in the trigger frame. In practice, if a node terminates payload data transmission before the TXOP ends, these nodes begin transmitting padding data (as defined in IEEE 802.11-15 / 617).

[0044] The TF frame also signals the bandwidth or width of the target composite channel, meaning a value of 20MHz, 40MHz, 80MHz, or 160MHz is added. The target composite channel is formed by transmitting the TF frame on the 20MHz main channel and replicating (repeating) the TF frame on each of the other 20MHz channels. As described above regarding the replication of the control frame, it can be expected that the nearby traditional nodes (non-HT or 802.11ac nodes) receiving the TF on the main channel will then set their NAV to the TXOP duration value specified in the TF frame. This prevents these traditional nodes from accessing channels in the target composite channel during the TXOP period.

[0045] Resource Units (RUs) can be reserved for specific nodes. In this case, the Access Point (AP) indicates the node that has reserved the RU in the Transfer Function (TF). This RU is called a scheduled RU. The indicated node does not need to contend for access to the scheduled RU reserved for that node.

[0046] To improve system efficiency for unmanaged traffic to the AP (e.g., uplink management frames from associated nodes, non-associated nodes intending to reach the AP, or simply unmanaged data traffic), IEEE 802.11-15 / 0604 proposes a new trigger frame (TF-R) based on the previous UL MU procedure, enabling random access to OFDMA TXOPs. In other words, a Resource Unit (RU) can be randomly accessed by more than one node. This RU is called a random RU and is thus indicated in the TF. The random RU can be used as the basis for contention between nodes intending to access the communication medium to send data.

[0047] The random resource selection process has not yet been defined. All that is known is that the trigger frame can define only the scheduled RU, or only the random RU within the target composite channel.

[0048] Regardless of the random resource selection process used, multi-user transmission based on trigger frame mechanisms should improve network capacity by making the overhead shared by all nodes. In fact, the overall latency overhead is reduced.

[0049] However, it is believed that the trigger frame mechanism still has overhead issues (mainly shifting from waiting time to filling time).

[0050] Specifically, the trigger frame mechanism only provides a general RU, in which padding must be performed to ensure that the TXOP reaches the end and to avoid interference with traditional nodes. This padding increases the overall overhead cost. Since so-called small packets use a very small portion of the allocation RU, this additional overhead cost due to padding is exacerbated for these so-called small packets.

[0051] Therefore, especially for small packets, the gain from reducing latency may not be sufficient to compensate for the loss caused by padding. As a result, contrary to the intended goal of introducing the trigger frame mechanism, the total overhead may not be reduced.

[0052] Aside from small packet scenarios, different types of data services typically coexist across various RUs, which have different requirements regarding the amount of data to be transmitted, latency, and TxOP duration. This heterogeneity of the different PPDUs transmitted by a node can lead to a large amount of padding data in some RUs, resulting in a significant reduction in channel utilization efficiency.

[0053] It can be noted that the use of different modulation (modulation and coding schemes) to handle the distance (from the node to the AP) and the changes in signal-to-noise ratio (changes in channel conditions) through different paths (i.e., through different RUs involving different nodes) may also exacerbate the filling problem.

[0054] Therefore, it is necessary to improve this situation and reduce the impact of padding on network efficiency.

[0055] In addition, network usage can be improved by utilizing different types of data services that coexist in various RUs. Summary of the Invention

[0056] The broad objective of this invention is to provide a wireless communication method and apparatus in a wireless network. The wireless network includes an access point and multiple nodes, all of which share the physical medium of the wireless network.

[0057] The present invention has been designed to overcome one or more of the above-described limitations.

[0058] In this context, the present invention seeks to provide a wireless communication method that improves network usage and, consequently, improves the mechanism for dealing with collisions in communication channels.

[0059] This invention is applicable to any wireless network, in which an access point provides a registration node having multiple sub-channels (or resource units) forming a communication channel. The communication channel is a basic channel, on which nodes listen to determine whether the basic channel is idle or busy.

[0060] This invention is particularly suitable for data transmission to APs in IEEE 802.11ax networks (and future versions).

[0061] A first main embodiment of the present invention provides a wireless communication method in a wireless network from the perspective of an access point. The wireless network includes an access point and a plurality of nodes. The wireless communication method includes, at the access point, a step of sending a trigger frame to the nodes. The trigger frame reserves at least one communication channel of the wireless network for transmission opportunities and defines a plurality of resource elements, i.e., a plurality of RUs, for forming the communication channel.

[0062] The trigger frame includes an indicator for restricting the data to be sent on at least one of the plurality of resource units to data with a restricted data type.

[0063] The same first principal embodiment of the present invention provides a wireless communication method in a wireless network from the perspective of a node, the wireless network including an access point and a plurality of nodes, the wireless communication method comprising the following steps at one of the plurality of nodes:

[0064] A trigger frame is received from the access point, wherein the trigger frame reserves at least one communication channel of the wireless network for transmission opportunities and defines multiple resource units, i.e., multiple RUs, for forming the communication channel;

[0065] Determine from the trigger frame an indicator for defining the restricted data types permitted for at least one of the plurality of resource units;

[0066] Determine data from the local transfer memory that has a type corresponding to the determined restricted data type; and

[0067] The determined data is transmitted from the resource unit to the access point.

[0068] Because the indicator specifies the restricted data type, the access point can drive or control the node in its process of selecting the data to be transmitted on the RU. As a result, the AP can efficiently tune the RU to suit the data type, thereby optimizing the use of the RU.

[0069] Relatedly, the present invention provides a communication device for use as an access point in a wireless network, the wireless network further comprising a plurality of nodes, the communication device for use as an access point comprising at least one microprocessor configured to perform a step of sending a trigger frame to the nodes, the trigger frame reserving at least one communication channel of the wireless network for transmission opportunities and defining a plurality of resource units for forming the communication channel.

[0070] The trigger frame includes an indicator for restricting the data to be sent on at least one of the plurality of resource units to data with a restricted data type.

[0071] From a node perspective, the present invention also provides a communication device in a wireless network, the wireless network including an access point and a plurality of nodes, the communication device being one of the plurality of nodes and including at least one microprocessor configured to perform the following steps:

[0072] A trigger frame is received from the access point, wherein the trigger frame reserves at least one communication channel of the wireless network for transmission opportunities and defines a plurality of resource units for forming the communication channel;

[0073] Determine from the trigger frame an indicator for defining the restricted data types permitted for at least one of the plurality of resource units;

[0074] Determine data from the local transfer memory that has a type corresponding to the determined restricted data type; and

[0075] The determined data is transmitted from the resource unit to the access point.

[0076] Optional features of embodiments of the invention are defined in the appended claims. Some of these features are described below with reference to methods, and these features can be converted into system features specifically for any node device according to embodiments of the invention.

[0077] In this embodiment, the restricted data type is defined as a small MAC packet relative to the MAC packets transmitted via the wireless network. As a result, the AP can force nodes to send their so-called small packets. Consequently, the nodes will spend less time acquiring TXOPs for sending small packets. This greatly helps reduce the overall overhead cost caused by small packets. As a result, network usage is improved.

[0078] In a specific embodiment, the small MAC packet is a MAC packet with a packet size smaller than a predetermined maximum small packet size (i.e., a threshold). For example, the predefined maximum small packet size is equal to the so-called RTS threshold parameter set for the wireless network according to the 802.11 standard. The RTS threshold parameter is known to be a manageable parameter of the 802.11 network used to determine when (i.e., from which size of MAC packet) the RTS / CTS handshake should precede the data packet.

[0079] As a result, small packets that would normally be handled without RTS / CTS handshakes are processed in TF bursts (i.e., small packets that should be avoided due to the overhead of RTS / CTS).

[0080] In a variant, the small MAC packet is one that has an overhead that is, for example, 20% or 30% greater than a predetermined maximum overhead (i.e., a threshold) due to the MAC header within the packet. In practice, these packets, which already have large internal overhead, should preferably be processed together in a burst to avoid excessive additional overhead for each packet.

[0081] There exist some types of packages that essentially possess one or more of the above definitions. For example, a control package is essentially a small package.

[0082] In a specific embodiment, the predetermined maximum packet size or the predetermined maximum overhead is specified in the trigger frame.

[0083] In an embodiment from the perspective of the access point, the wireless communication method may further include: adjusting the predetermined maximum packet size or the predetermined maximum overhead from one trigger frame to another based on network statistics relating to one or more previous transmission opportunities.

[0084] These two regulations enable APs to efficiently manage small packets as network conditions evolve.

[0085] In an embodiment viewed from a node's perspective, the node's local transfer memory includes multiple ordered transfer queues, each associated with a dynamic priority value (i.e., the priority value evolves over time. In the 802.11 scheme, the priority value corresponds to the value of a contention backoff counter associated with each transfer queue); and

[0086] Determining data having a type corresponding to the determined restricted data type includes selecting at least one packet from a set of one or more packets, the set including one of the following:

[0087] The first small packet from the transmission queue with the highest priority value.

[0088] The first small packet from each transmission queue,

[0089] All small packets from all transmission queues,

[0090] All packets in the transmission queue that only stores small packets.

[0091] Therefore, strategies related to nodes can be adjusted.

[0092] In this embodiment, the at least one resource element has a minimum bandwidth permitted by the 802.11 standard. Currently, a 20MHz channel can be divided into a maximum of nine identical resource elements, i.e., the minimum bandwidth is 2.03MHz. This specification optimizes the use of RUs for small packets. As a result, this specification also increases the number of nodes that can transmit small packets on RUs of a licensed composite channel.

[0093] In this embodiment, the restricted data type defines the data service type. As a result, the AP can force nodes to send certain types of data in response to a specific TF. When this occurs as will happen below, the AP will then adjust the RUs according to the allowed service types to optimize network bandwidth usage.

[0094] In a specific embodiment, the restricted data service type is one of the four access categories defined in the 802.11 standard: AC_BK for background data, AC_BE for best-effort data, AC_VI for video applications, and AC_VO for voice applications.

[0095] In a specific embodiment from the perspective of the access point (AP), the wireless communication method further includes: determining the restricted data service type from a plurality of predefined service types (e.g., the four access categories mentioned above) based on the following:

[0096] Network statistics relating to the amount of data received in one or more previous transmission opportunities for each of the plurality of predefined service types, or

[0097] The total queue size for each of the multiple predefined service types is calculated by summing the sizes of the transmission queues associated with that predefined service type in the node. The AP can obtain this information from each node because the 802.11 standard MAC header of the PPDU sent by the node includes a "Queue Size" field, which the node uses to indicate the buffered traffic volume for a given service type. Therefore, the AP can calculate global statistics related to the total queue size for each service type and construct associated trigger frames with dedicated RU service types.

[0098] In a specific embodiment from the node's perspective, determining data with a type corresponding to the determined restricted data type from the local transfer memory involves selecting only data with the determined restricted data type from the transfer queues storing the data. This is particularly applicable when the restricted data type is one of the four access categories defined above. In this case, the processing at the node is very simple because it only requires accessing a single transfer queue based on the restricted data type associated with the RU used.

[0099] In a specific embodiment from the node's perspective, the node's local transmission memory includes multiple transmission queues, each associated with a dynamic priority value and a service type, and the wireless communication method further includes the following steps:

[0100] The transmission queues are considered sequentially from highest to lowest priority value until data is sent on a resource unit.

[0101] For each transmission queue considered in turn, it is determined whether the resource unit in the communication channel has a restricted service type, and if the determination is positive, data from the currently considered transmission queue is transmitted on the determined resource unit.

[0102] This configuration maintains the priority order as defined in the 802.11 standard, thereby preserving fairness among nodes.

[0103] In one embodiment, the wireless communication method further includes determining the frequency of sending trigger frames with restricted type indicators based on network statistics related to one or more previous transmission opportunities. This helps improve network usage because the AP dynamically adjusts the number of opportunities for nodes to transmit specific data (small packets or those with service types) to suit network conditions.

[0104] In other embodiments, the wireless communication method further includes determining the number of resource units forming the communication channel based on network statistics related to one or more previous transmission opportunities. This helps improve network utilization because it dynamically adjusts the number of nodes that can transmit data during the next TXOP to suit network conditions.

[0105] In a specific embodiment, the network statistics include one or more of the following:

[0106] The number of nodes registered to the access points in the wireless network.

[0107] The number of collisions or the collision rate (the number of RUs colliding among multiple RUs) that occurred during the one or more previous transmission opportunities.

[0108] The distribution of packet sizes received by the access point, particularly the packet size distribution relative to the maximum packet size (i.e., the defined small packet).

[0109] The amount of data transmitted by the node

[0110] For the amount of data transmitted by the node from each of the multiple predefined service types, and

[0111] The media busy rate, for example, the ratio of media busy time in a given period (e.g., one second).

[0112] In some embodiments, the trigger frame includes a single indicator for defining the same restricted data type for all resource units of the at least one communication channel (i.e., for the entire composite channel). This minimizes the overhead caused by the indicator.

[0113] In a variant, the trigger frame includes an indicator for each resource unit, thereby defining different restricted data types for each resource unit. This allows more nodes to send data during the current TXOP, because nodes with different types of data can now send data via RUs within the same communication channel.

[0114] A second main embodiment of the present invention provides a wireless communication method in a wireless network from the perspective of an access point. The wireless network includes an access point and a plurality of nodes. The wireless communication method includes, at the access point, a step of sending a trigger frame to the nodes. The trigger frame reserves at least one communication channel of the wireless network for transmission opportunities and defines a plurality of resource elements, i.e., a plurality of RUs, for forming the communication channel, wherein at least one resource element has a predefined resource element bandwidth.

[0115] The wireless communication method further includes, at the access point, the following step: the step is used to determine the duration of the transmission opportunity based on the predefined resource unit bandwidth and the predetermined maximum small packet size, so that the at least one resource unit can include only MAC packets with a packet size larger than the predetermined maximum small packet size.

[0116] This configuration allows the access point to force nodes to transmit their so-called small packets (i.e., packets with a size larger than the predetermined maximum packet size). This is achieved by adjusting the size of the TXOP appropriately given a predefined width for the resource unit.

[0117] One advantage of using this method to force the transmission of small packets is full compliance with the 802.11ax standard. In fact, no additional information is provided, and the node still performs the same processing to select data that matches the RU supply.

[0118] Relatedly, the present invention provides a communication device for use as an access point in a wireless network, the wireless network further comprising a plurality of nodes, the communication device for use as an access point comprising at least one microprocessor configured to perform the step of sending a trigger frame to the nodes, the trigger frame reserving at least one communication channel of the wireless network for transmission opportunities and defining a plurality of resource elements for forming the communication channel, wherein at least one resource element has a predefined resource element bandwidth.

[0119] The microprocessor is further configured to perform the following step, which is to determine the duration of the transmission opportunity based on the predefined resource unit bandwidth and the predetermined maximum small packet size, such that the at least one resource unit can include only MAC packets with a packet size larger than the predetermined maximum small packet size.

[0120] Optional features of embodiments of the invention are defined in the appended claims. Some of these features are described below with reference to methods, and these features can be converted into system features specifically for any node device according to embodiments of the invention.

[0121] In this embodiment, the predefined maximum packet size is equal to the so-called RTS threshold parameter set for the wireless network according to the 802.11 standard.

[0122] In this embodiment, the predefined resource unit width is the minimum bandwidth permitted by the 802.11 standard.

[0123] As described above with reference to the first main embodiment, the frequency for sending such trigger frames or the number of resource units in the communication channel can also be dynamically determined.

[0124] A third main embodiment of the present invention provides a wireless communication method in a wireless network from the perspective of a node. The wireless network includes an access point and multiple nodes. The wireless communication method at the access point includes the following steps:

[0125] A trigger frame is sent to the node. This trigger frame reserves at least one communication channel of the wireless network for transmission opportunities and defines multiple resource elements (RUs) for forming the communication channel, each resource element having the same time duration.

[0126] The resource units within the communication channel have different bandwidths.

[0127] The same third principal embodiment of the present invention provides a wireless communication method in a wireless network from the perspective of a node, the wireless network including an access point and a plurality of nodes, the wireless communication method comprising the following steps at one of the plurality of nodes:

[0128] A trigger frame is received from the access point, the trigger frame reserving at least one communication channel of the wireless network for transmission opportunities, and defining multiple resource units (RUs) for forming the communication channel, wherein the multiple resource units have the same time length; and

[0129] Data is transmitted from one of the plurality of resource units to the access point.

[0130] The resource units within the communication channel have different bandwidths.

[0131] Network bandwidth usage has been optimized. This is achieved by giving resource units different bandwidths (i.e., different transmission capacities).

[0132] As a result, nodes can efficiently select resource units that match their needs, thereby minimizing fill time.

[0133] Relatedly, the present invention provides a communication device for use as an access point in a wireless network, the wireless network further comprising a plurality of nodes, the communication device for use as an access point comprising at least one microprocessor configured to perform the step of sending a trigger frame to the nodes, the trigger frame reserving at least one communication channel of the wireless network for transmission opportunities and defining a plurality of resource units for forming the communication channel, the plurality of resource units having the same duration.

[0134] The resource units within the communication channel have different bandwidths.

[0135] From a node perspective, the present invention also provides a communication device in a wireless network, the wireless network including an access point and a plurality of nodes, the communication device being one of the plurality of nodes and including at least one microprocessor configured to perform the following steps:

[0136] A trigger frame is received from the access point, the trigger frame reserving at least one communication channel of the wireless network for transmission opportunities and defining a plurality of resource elements for forming the communication channel, wherein the plurality of resource elements have the same time length; and

[0137] Data is transmitted from one of the plurality of resource units to the access point.

[0138] The resource units within the communication channel have different bandwidths.

[0139] Optional features of embodiments of the invention are defined in the appended claims. Some of these features are described below with reference to methods, and these features can be converted into system features specifically for any node device according to embodiments of the invention.

[0140] In the embodiments, each of the resource units is associated with a data service type selected from four access categories defined in the 802.11 standard: AC_BK for background data, AC_BE for best-effort data, AC_VI for video applications, and AC_VO for voice applications.

[0141] In a specific embodiment, resource units associated with AC_BK and AC_BE service types have a first bandwidth, resource units associated with AC_VO have a bandwidth equal to twice the first bandwidth, and resource units associated with AC_VI have a bandwidth equal to four times the first bandwidth. This specification optimizes bandwidth usage because the RU size is adjusted to suit the size of the content transmitted by these RUs. As a result, the size of resource units dedicated to small content is adjusted accordingly, thereby avoiding excessive padding.

[0142] In a more specific embodiment, the first bandwidth is equal to the minimum bandwidth permitted by the 802.11 standard. Currently, a 20MHz channel is divided into a maximum of nine identical resource elements, i.e., the minimum bandwidth is 2.03MHz. This is to provide optimal granularity for access points when designing resource elements.

[0143] In a specific embodiment, the duration of the resource element is less than or equal to one-quarter of the TXOP limit parameter set for the wireless network according to the 802.11 standard. This provision is advantageously combined with the aforementioned adjustment of the relative size (width) of the resource element based on its associated AC_BK, AC_BE, AC_VI, or AC_VO service type. In fact, utilizing the RU width can significantly reduce the duration of the TXOP, and thus reduce the filling of underutilized RUs.

[0144] In node-related embodiments, each of the resource units is associated with a data service type, and the wireless communication method further includes performing the following steps at the node:

[0145] Transmit data with the same service type as the service type associated with that resource unit on a resource unit.

[0146] This helps access point-driven nodes use resource units. Access points can define the service type of each resource unit in the trigger frame.

[0147] In one embodiment, the node includes multiple transmission queues storing data to be transmitted, each transmission queue being associated with a dynamic priority value; and the wireless communication method further includes the following steps:

[0148] Determine whether one of the plurality of resource units matches the amount of data to be sent in the transmission queue with the highest priority value, and

[0149] If the determination is positive, data from the transmission queue with the highest priority value is transmitted on the matching resource unit.

[0150] Of course, other transmission queues can be considered in order of priority to transmit the contents of these other transmission queues in an appropriate (i.e., appropriately sized) RU.

[0151] In one embodiment, the wireless communication method further includes: adapting a modulation scheme for modulating data on the resource unit, the adaptation maximizing the duration of data transmission within the transmission opportunity. This also helps reduce padding in the RU while strengthening the data to avoid errors on the communication channel.

[0152] In embodiments relating to access points, each of the resource units is associated with a data service type, and the wireless communication method further includes the following steps:

[0153] The bandwidth of the resource unit is determined based on statistics relating to data related to each service type received in one or more previous transmission opportunities.

[0154] This is to enable the access point to dynamically adjust the RU design to suit the node's needs, that is, to dynamically adjust as network conditions evolve.

[0155] In a specific embodiment, the bandwidth of the resource unit is further adjusted based on the number of nodes registered to the access point. This provision also facilitates adjusting the number of RUs based on the number of nodes, because the bandwidth of the RUs can be adjusted to allow one or more RUs to be added or removed from the communication channel.

[0156] In a specific embodiment, the bandwidth of the resource unit associated with the service type is further adjusted based on the modulation scheme used by the node to transmit data of the associated service type in one or more previous transmission opportunities. This provision helps reduce padding in the RU at the end of the transmission of useful data, while enhancing the robustness of the transmitted data to avoid transmission errors.

[0157] In one embodiment, the wireless communication method further includes determining the number of resource units for forming the communication channel based on network statistics related to one or more previous transmission opportunities.

[0158] The same statistical data as defined above can be used. In particular, the type of data service (video, audio, background, best-effort service), the number of each data service type, the number of nodes, the modulation scheme (MCS) used by each node, the modulation scheme (MCS) used on each RU, and the identification of stable services (video streaming, VoIP, etc.) or random services (web browsing, control frames, etc.) can be used.

[0159] Another aspect of the invention relates to a non-transitory computer-readable medium storing a program that, when executed by a microprocessor or computer system in a device connected to a wireless network, causes the device to perform any of the methods defined above.

[0160] The non-transitory computer-readable medium may have features and advantages similar to those described above and below in relation to the methods and node devices.

[0161] Another aspect of the present invention relates to a wireless communication method in a wireless network, the wireless network comprising, substantially as shown herein with reference to the accompanying drawings. Figure 8 , 9 Access points and multiple nodes as shown in any of the figures 10a, 10b, 11, 12 and 13.

[0162] At least a portion of the method according to the invention can be implemented by a computer. Therefore, the invention can take the form of a fully hardware embodiment, a fully software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects generally referred to herein as a "circuit," "module," or "system." Furthermore, the invention can take the form of a computer program product embodied in any tangible medium containing computer-usable program code.

[0163] Because this invention can be implemented in software, it can be embodied as computer-readable code to be provided to a programmable device on any suitable carrier medium. Tangible carrier media may include storage media such as hard disk drives, magnetic tape devices, or solid-state storage devices. Transient carrier media may include signals such as electrical signals, electronic signals, optical signals, sound signals, magnetic signals, or electromagnetic signals (e.g., microwave or RF signals). Attached Figure Description

[0164] Further advantages of the present invention will become apparent to those skilled in the art upon examination of the accompanying drawings and detailed description. Embodiments of the invention will now be described by way of example only with reference to the following drawings.

[0165] Figure 1 This diagram illustrates a typical wireless communication system that can implement embodiments of the present invention;

[0166] Figure 2 This is a schematic illustration of the timeline of a traditional communication mechanism according to the IEEE 802.11 standard;

[0167] Figure 3 This demonstrates 802.11ac channel allocations supporting channel bandwidths of 20MHz, 40MHz, 80MHz, or 160MHz as known in the prior art;

[0168] Figure 4 An example of an 802.11ax uplink OFDMA transmission mechanism is shown, in which the AP sends a trigger frame on an 80MHz channel known in the art to reserve transmission opportunities for OFDMA subchannels (resource units);

[0169] Figure 5 This illustrates a typical communication line based on a typical random assignment.

[0170] Figure 5a An example of the use of 8 RUs forming a composite channel is shown;

[0171] Figure 6 A schematic representation of a communication device or station according to an embodiment of the present invention is shown;

[0172] Figure 7 A schematic representation of a wireless communication device according to an embodiment of the present invention is shown;

[0173] Figure 8 The flowchart illustrates the general steps of the first embodiment of the present invention from the perspective of the access point;

[0174] Figure 9 The flowchart illustrates the general steps of the first embodiment of the present invention from the perspective of nodes;

[0175] Figure 10a and 10b The general steps of the second embodiment of the present invention are illustrated from the perspective of the access point using a flowchart;

[0176] Figure 11 The flowchart illustrates the general steps of the second embodiment of the present invention from the perspective of nodes;

[0177] Figure 12 The general steps of the third embodiment of the present invention are illustrated from the perspective of the access point using a flowchart;

[0178] Figure 13 The general steps of the third embodiment of the present invention are illustrated from the perspective of nodes using a flowchart;

[0179] Figure 14 An example of a composite channel RU designed according to a third embodiment is shown; and

[0180] Figure 15 The present invention presents a typical format for notifying RU attributes in the form of signals according to the first, second and third embodiments of the present invention. Detailed Implementation

[0181] The invention will now be described using specific, non-limiting exemplary embodiments and with reference to the accompanying drawings.

[0182] Figure 1 A communication system is shown in which multiple communication nodes (or stations) 101–107 exchange data frames via a wireless transmission channel 100 of a wireless local area network (WLAN) under the management of a central station or access point (AP) 110. The wireless transmission channel 100 is defined by an operating frequency band, which consists of a single channel or multiple channels forming a composite channel.

[0183] Accessing the shared wireless medium to send data frames is based on CSMA / CA technology, which listens for carriers and avoids collisions by separating concurrent transmissions in space and time.

[0184] Carrier sensing in CSMA / CA is performed using both physical and virtual mechanisms. Virtual carrier sensing is achieved by transmitting control frames before transmitting data frames to reserve the medium.

[0185] Next, before transmitting a data frame, the source node first attempts to listen to the medium that has been idle for at least one DIFS (Digital InterFrame Spacing) time period through physical mechanisms.

[0186] However, if the shared radio medium is detected to be busy during the DIFS period, the source node continues to wait until the radio medium becomes idle. To do this, the source node initiates a countdown backoff counter designed to expire after multiple time slots randomly selected between [0, CW], where CW (an integer) is called the Contention Window. This backoff mechanism or process forms the basis of a collision avoidance mechanism that postpones transmission time by random intervals, thereby reducing the probability of collisions on the shared channel. After the backoff period, if the medium is idle, the source node can transmit data or control frames.

[0187] One problem with wireless data communication is that the source node cannot listen while transmitting, thus preventing it from detecting data corruption caused by channel fading, interference, or collisions. The source node remains unaware of the corruption in the transmitted data frames and continues to transmit frames unnecessarily, wasting access time.

[0188] Therefore, the CSMA / CA collision avoidance mechanism provides a positive acknowledgment (ACK) of the data frame sent by the receiving node when the frame is successfully received, so as to notify the source node that the data frame sent is not corrupted.

[0189] ACK is transmitted at the end of the reception of a data frame, immediately following a period of time known as the Short Interframe Spacing (SIFS).

[0190] If the source node does not receive an ACK within the specified ACK timeout, or detects that a different frame has been transmitted on the channel, the source node can infer that the data frame has been lost. In this case, the source node typically reschedules the frame transmission according to the backoff process described above. However, if only the ACK is corrupted, and the data frame is correctly received by the receiving node, this can be considered a waste of bandwidth.

[0191] To improve the collision avoidance efficiency of CSMA / CA, a four-way handshake mechanism can be optionally implemented. One implementation is known as RTS / CTS switching as defined in the 802.11 standard.

[0192] RTS / CTS switching involves exchanging control frames before transmitting data frames during a transmission opportunity known as TXOP in the 802.11 standard as described below, to preserve the radio medium and thus protect data transmission from any further collisions.

[0193] Figure 2 The behavior of three groups of nodes during conventional communication over a 20 MHz channel via 802.11 medium is illustrated: the sending node or source node 20, the receiving node or visited address node or destination node 21, and other nodes 22 not involved in the current communication.

[0194] When backoff processing 270 begins before data transmission, as described above, the station (e.g., source node 20) initializes its backoff time counter to a random value. The backoff time counter is decremented by 1 for each time slot interval 260 as long as the wireless medium is detected as idle (the countdown starts from T0,23, as shown in the figure).

[0195] Channel sensing can be performed, for example, using idle channel assessment (CCA) signal detection.

[0196] Carrier Sense Capability (CCA) is a WLAN carrier sensing mechanism defined in the IEEE 802.11-2007 standard as part of the Physical Medium Dependency (PMD) and Physical Layer Convergence Protocol (PLCP) layers. CCA includes two functions:

[0197] Carrier Sense (CCA-CS) is the ability of a receiving node to detect and decode the 802.11 frame preamble. The duration for which the medium will be occupied can be inferred from the PLCP header field, and in the event of such an 802.11 frame preamble being detected, the CCA flag remains busy until data transmission is complete.

[0198] Energy Detection (CCA-ED) is the ability of a receiving node to detect non-802.11 energy in a specific 20MHz channel and back off data transmission. Essentially, it listens for the energy level on the 20MHz channel and compares that energy level to an ED threshold used to distinguish between the presence and absence of 802.11 energy in the channel. The ED threshold is, for example, defined as 20dB higher than the minimum sensitivity of the node's PHY layer. If the in-band channel energy exceeds this threshold, CCA remains active until the medium energy falls below the threshold again.

[0199] The time unit in the 802.11 standard is the slot interval, referred to by the parameter “aSlotTime”. This parameter is specified by the PHY (physical) layer (e.g., in the case of the 802.11n standard, aSlotTime equals 9 μs). All dedicated space durations (e.g., backoff) are added to the SIFS value as a multiple of this time unit.

[0200] If a transmission is detected on the wireless medium channel, the backoff time counter is "frozen" or paused (for other nodes 22 where the backoff time counter has decreased, the countdown stops at T1,24).

[0201] The countdown of the backoff time counter resumes or restarts after the DIFS period when the radio medium is detected to be idle again. This is the case for other nodes at T2, 25 once the transmission opportunity TXOP granted to source node 20 ends and the DIFS period 28 has elapsed. Therefore, DIFS 28 (DCF inter-frame interval) defines the minimum waiting time for the source node before attempting to transmit some data. In fact, DIFS = SIFS + 2 * aSlotTime.

[0202] When the backoff time counter reaches zero (26) at T1, the timer expires, the corresponding node 20 requests access to the medium to be authorized TXOP, and reinitializes the 29 backoff time counter with a new random backoff value.

[0203] In the example of the diagram implementing the RTS / CTS scheme, at T1, the source node 20 that wants to transmit data frame 230 immediately after the channel is detected to be idle in DIFS or immediately after the backoff period as described above, sends a special short frame or message as a medium access request instead of the data frame itself to reserve the radio medium.

[0204] Media access requests are known as request to transmit (RTS) messages or frames. An RTS frame typically includes the addresses of the source node and the receiving node (“Destination 21”) and the duration for which the radio medium is to be reserved for the transmission of control frames (RTS / CTS) and data frames 230.

[0205] When an RTS frame is received and the radio medium is detected as idle, the receiving node 21 responds with a medium access response known as Allow Transmission (CTS) after a SIFS period 27 (e.g., 16 μs in the case of the 802.11n standard). The CTS frame also includes the addresses of the source and receiving nodes and indicates the remaining time required to transmit the data frame, calculated from the time the CTS frame was first transmitted.

[0206] The CTS frame is regarded by the source node 20 as an acknowledgment of the source node's request to retain the shared radio medium for a given duration.

[0207] Therefore, source node 20 expects to receive CTS frame 220 from receiving node 21 before sending data 230 using a unique and unicast frame (one source address and one visited or destination address).

[0208] Therefore, source node 20 is able to send data frame 230 after the new SIFS time period 27 if it has correctly received CTS frame 220.

[0209] To provide QoS support, 802.11 defines various priority levels for the data that the source node 20 wants to transmit. These levels are primarily defined based on the nature of the data.

[0210] In 802.11e, four access classes (ACs) are defined:

[0211] AC_BK has the lowest priority for background data.

[0212] AC_BE has the next priority for best-effort service data.

[0213] AC_VI has a higher priority for video applications, and

[0214] AC_VO has the highest priority for voice applications.

[0215] Each access category has one or more service classes as defined in IEEE standard 802.11e-2005.

[0216] In practice, source node 20 has a transmission buffer queue for each access class and therefore implements a backoff counter for each access class. The backoff counter with the lowest value from the four AC backoff counters is considered the backoff counter of the aforementioned node because it is the first backoff counter to reach zero.

[0217] After receiving the transmitted data frame correctly, receiving node 21 sends ACK frame 240 after the new SIFS time period 27.

[0218] If source node 20 does not receive ACK 240 within the specified ACK timeout (generally within TXOP), or if source node 20 detects that different frames have been transmitted on the wireless medium, the source node again uses the backoff procedure to reschedule the frame transmission.

[0219] Since the RTS / CTS four-way handshake mechanism 210 / 220 is optional in the 802.11 standard, the source node 20 can send data frame 230 immediately when its backoff time counter reaches zero (i.e., at T1).

[0220] The transmission request duration defined in RTS and CTS frames defines the length of the authorized transmission opportunity (TXOP) and can be monitored by any listening node in the wireless network. Figure 2 Read from "Other Nodes 22" in the table.

[0221] To do this, each node has a data structure in memory known to allocate a vector or NAV to the network, used to store the known duration for which the medium will remain busy. When listening for a control frame (RTS 210 or CTS 220) that is not addressed, the listening node 22 updates its NAV (NAV 255 associated with RTS and NAV 250 associated with CTS) with the requested transmission duration specified in the control frame. Thus, the listening node 22 maintains in memory the duration for which the wireless medium will remain busy.

[0222] By pausing the associated timers of other nodes 22 and then resuming the timers when the NAV expires, access to the wireless medium by other nodes 22 is thus delayed.

[0223] This prevents listening node 22 from transmitting any data or control frames during that period.

[0224] Receiver Node 21 may not have correctly received RTS frame 210 due to message / frame collisions or fading. Even if Receiver Node 21 receives RTS frame 210, it cannot always respond with CTS 220 because, for example, Receiver Node 21's NAV is set (i.e., another node has reserved the medium). In any case, Source Node 20 enters a new backoff procedure.

[0225] The RTS / CTS four-way handshake mechanism is highly efficient in terms of system performance, especially for large frames, because it reduces the length of messages involved in contention handling.

[0226] In detail, assuming perfect channel listening by all communication nodes, a collision can only occur if two (or more) frames are transmitted in the same time slot after DIFS 28 (DCF inter-frame interval), or if the backoff counters of the communication nodes themselves reach zero at almost the same time (T1). If the two source nodes use the RTS / CTS mechanism, such a collision can only occur with RTS frames. Fortunately, since a CTS response can be quickly determined beforehand, this collision can be detected in advance.

[0227] As mentioned above, the original IEEE 802.11 MAC always sends an acknowledgment (ACK) frame 240 after receiving each data frame 230.

[0228] However, this collision limits the optimal functioning of wireless networks. As mentioned above, simultaneous transmission attempts from multiple wireless nodes can lead to collisions. The 802.11 backoff procedure was initially introduced for DCF mode as a fundamental solution to avoid collisions. In the emerging IEEE 802.11n / ac / ax standards, the backoff procedure is still used as a basic method to support distributed access between mobile stations or nodes.

[0229] To meet the growing demand for faster wireless networks to support bandwidth-intensive applications, 802.11ac is designed for greater bandwidth transmission via multi-channel operation. Figure 3 This shows the 802.11ac channel allocation that supports composite channel bandwidths of 20MHz, 40MHz, 80MHz, or 160MHz.

[0230] IEEE 802.11ac introduces a limited number of predefined subsets of 20MHz channels to form a unique predefined composite channel configuration that can be reserved for any 802.11ac node on a wireless network to transmit data.

[0231] The figure shows a predefined subset, corresponding to channel bandwidths of 20MHz, 40MHz, 80MHz, and 160MHz, compared to the 20MHz and 40MHz supported only by 802.11n. In practice, 20MHz composite channels 300-1 to 300-8 are cascaded to form wider communication composite channels.

[0232] In the 802.11ac standard, channels in each predefined 40MHz, 80MHz, or 160MHz subset are continuous within the operating frequency band; that is, holes (missing channels) are not allowed in composite channels ordered within the operating frequency band.

[0233] The 160MHz channel bandwidth consists of two 80MHz channels, which may or may not be frequency-contiguous. The 80MHz channel and the 40MHz channel consist of two adjacent or consecutive 40MHz channels and a 20MHz channel, respectively.

[0234] On the "primary channel" (300-3), TxOPs are authorized to nodes via the Enhanced Distributed Channel Access (EDCA) mechanism. In practice, for each composite channel with bandwidth, 802.11ac designates one channel as "primary," meaning that this channel is used to compete for access to the composite channel. The 20MHz primary channel is shared by all nodes (STAs) belonging to the same basic set, i.e., managed by or registered to the same local access point (AP).

[0235] However, in order to ensure that other traditional nodes (i.e., traditional nodes that do not belong to the same set) do not use the secondary channel, it is proposed to replicate the control frames (e.g., RTS frames / CTS frames) used to preserve the composite channel on each 20MHz channel in the composite channel.

[0236] As previously addressed, the IEEE 802.11ac standard allows for the bonding of up to four or even eight 20MHz channels. Due to the limited number of channels (19 in the 5GHz band in Europe), channel saturation becomes a problem. In fact, in densely populated areas, even with 20MHz or 40MHz band usage for each wireless LAN cell, the 5GHz band will almost certainly become saturated.

[0237] The development of the 802.11ax standard aims to enhance the efficiency and usability of wireless channels in dense environments.

[0238] From this perspective, multi-user transmission characteristics can be considered, allowing multiple simultaneous transmissions to multiple users in both the downlink and uplink directions. In the uplink, multi-user transmission can be used to reduce the probability of collisions by allowing multiple nodes to transmit simultaneously.

[0239] To practically implement this multi-user transmission, it has been proposed to divide the licensed 20MHz channel (300-1 to 300-4) into sub-channels 410 (basic sub-channels, also known as subcarriers or resource units (RUs)), where multiple users can share these sub-channels 410 in the frequency domain, for example, based on Orthogonal Frequency Division Multiple Access (OFDMA) technology. Each RU can be defined by multiple tones, and the 20MHz channel contains multiple 242 available tones.

[0240] refer to Figure 4 This illustrates this type of multi-user transmission.

[0241] OFDMA's multi-user feature allows the AP to assign different RUs to different nodes, increasing contention. This can help reduce contention and conflicts within 802.11 networks.

[0242] In contrast to downlink OFDMA (where the AP can directly send multiple data to multiple stations (supported by specific indications within the PLCP header)), a triggering mechanism has been adopted for the AP to trigger uplink communication from each node.

[0243] To support uplink multi-user transmission (during preemptive TxOP), an 802.11ax AP must provide signaling information to set up its NAV for two legacy stations (non-802.11ax nodes) and to determine resource unit allocation for 802.11ax nodes.

[0244] In the following description, the term "traditional" refers to a non-802.11ax node, which means an 802.11 node that does not support prior technology for OFDMA communication.

[0245] like Figure 4 As shown in the example, the AP sends a trigger frame (TF) 430 to the target 802.11ax node. The TF frame signals the bandwidth or width of the target composite channel, which means adding a value of 20MHz, 40MHz, 80MHz, or 160MHz. The TF frame is transmitted on the primary channel at 20MHz, and this TF frame is copied (repeated) on each of the other 20MHz channels, thus forming the target composite channel. As described above regarding the copying of the control frame, it can be expected that the nearby legacy nodes (non-HT or 802.11ac nodes) receiving the TF on the primary channel will then sequentially set their NAV to the value specified in the TF frame. This prevents these legacy nodes from accessing the channels in the target composite channel during TXOP.

[0246] The trigger frame (TF) can specify at least one resource unit (RU) 410 or a "random RU", where the "random RU" can be randomly accessed by more than one node. In other words, the random RU specified or assigned by the AP in the TF can be used as the basis for contention between nodes that intend to access the communication medium to send data. Figure 5 A typical embodiment of this random allocation is shown.

[0247] In addition to, or instead of, a random RU, a trigger frame (TF) can also specify a scheduled resource unit. Scheduled RUs can be reserved for certain nodes, in which case there is no need for contention to access such RUs.

[0248] In this context, the TF includes information specifying the type (scheduled or random) of the RUs. For example, labels can be used to indicate that all RUs defined in the TF are scheduled (label = 1) or random (label = 0). In this case, random RUs and scheduled RUs are mixed within the TF, and the type of each RU can be defined using a bitmap (or any other equivalent information) (the bitmap can follow a known order of RUs throughout the communication channel).

[0249] OFDMA's multi-user feature allows the AP to assign different RUs to different nodes, increasing contention. This can help reduce contention and conflicts within 802.11 networks.

[0250] exist Figure 4 In the example, each 20MHz channel is subdivided in the frequency domain into four subchannels, or RU 410, typically each 5MHz in size. These subchannels (or resource elements) are also referred to as “subcarriers” or “traffic channels”.

[0251] Of course, the number of RUs divided into 20MHz segments can be different from 4. For example, 2 to 9 RUs can be provided (therefore each RU has a size of 10MHz to about 2.2MHz).

[0252] As shown in the figure, all RU 410 have the same time length 230 (corresponding to the length of TXOP).

[0253] Figure 5 A typical communication line is shown according to a typical random allocation procedure 500, which can be used by nodes to access random RUs indicated in a TF. This random allocation procedure is based on the reuse of a node's backoff counter value to assign an RU to a node in the network to send data.

[0254] The AP sends a trigger frame TF that defines the RU as having random access. In the example in the figure, eight RUs with the same bandwidth are defined for a 40MHz composite channel, and TF 430 is replicated on two 20MHz channels to form a composite channel. In other words, the network is configured to process four OFDMA resource elements for each 20MHz channel.

[0255] Each node STA1 to STAn is a transmission node for the receiving AP. As a result, each node has at least one active backoff value (corresponding to the AC backoff counter with the lowest value).

[0256] The random allocation process for a node among multiple nodes with active backoff 510 includes the following steps: a first step for determining a subchannel or RU of the communication medium available for contention from the trigger frame; a second step for verifying that the local active backoff value of the node under consideration is not greater than the number of RUs detected as available; and then, a step of transmitting data on RUs with a number equal to the backoff value.

[0257] In other words, random RUs can be indexed in TF, and each node uses an RU with an index equal to the node's backoff value.

[0258] As shown in the figure, some resource units, such as RUs with indices of 2 (410-2), 5, 7, and 8, can be omitted. This is due to randomization, and in this example, because no node has a backoff value equal to 2, 5, 7, or 8 when sending a TF.

[0259] Figure 5a An example of the use of 8 RUs forming a composite channel is shown (of course, the number of OFDMA RUs can vary). These 8 RUs have the same design, namely the same time length (corresponding to the TXOP duration) and the same bandwidth.

[0260] The AP sends TFs with a duration of, for example, 3ms for 550 and multiple random RUs and / or scheduled RUs.

[0261] Upon receiving a TF, the node accesses the scheduled RU or competes for access to a random RU (e.g., as referenced). Figure 5 (as described above), and then the node's data is transmitted in the visited RU during the time corresponding to the TXOP duration of 900.

[0262] In this example, the data services sent by the node are heterogeneous, that is, video, voice, web applications, control frames, etc. are mixed in the same uplink (UL) multi-user (MU) OFDMA transmission.

[0263] As shown in the figure, the obtained PPDU is a PPDU that is very different from other PPDUs in terms of duration.

[0264] This is because the amount of data to be transmitted changes dramatically from one data type to another.

[0265] This is also because, even for the same type of data service or the same amount of data to be transmitted, the modulation used by the node (which is related to the distance between the transmitting node and the access point) significantly modifies the transmission duration. Depending on the modulation used (MCS0-9 in IEEE 802.11ac), the number of bits carried by each OFDM symbol changes, and for a given amount of data, the transmission duration also changes knowing that the symbol duration is fixed.

[0266] For example, node STA1 can transmit web browsing services (AC_BE: access category best-effort service), node STA2 can transmit control frames, and node STA4 can transmit large aggregates of video data frames (AC_VI: access category video).

[0267] As shown in the figure, the PPDU sent by STA4 (553) uses the entire TXOP duration of the UL MU OFDMA, while the PPDU sent by STA1 (551) needs to be padded (552) to maintain the signal on RU#1 for the entire TXOP duration. In fact, if the data transmission lasts less than the TXOP duration 550, the node must padded (send padded data) until the UL MU transmission ends.

[0268] Figure 5a This example illustrates some of the drawbacks of UL MU transmission in certain scenarios.

[0269] Because a large amount of padding is required to maintain signal until the end of TXOP 230, so-called "small packets" like those sent by STA7 incur significant overhead. This situation needs to be mitigated, and the efficiency of the frame triggering mechanism when transmitting small packets needs to be improved.

[0270] Furthermore, due to the heterogeneity of the different PPDUs transmitted by the nodes, a large amount of padding data is sent on the RUs. The trigger frame mechanism needs to be adjusted to accommodate the heterogeneity of data between RUs.

[0271] All these requirements attempt to improve network usage, specifically by reducing padding.

[0272] The embodiments of the present invention find specific applications in the enhancements to the 802.11ac standard, and more precisely in the context of 802.11ax, where it is more certain that dense wireless environments will have the previous limitations.

[0273] Embodiments of the present invention provide improved wireless communication, which features more efficient bandwidth utilization while limiting the risk of collisions. In particular, efforts are made to reduce the amount of padding data.

[0274] A typical wireless network is an IEEE 802.11ac network (and later versions). However, this invention is applicable to any wireless network including an access point AP 110 and multiple nodes 101-107 transmitting data to that AP via multi-user transmission. This invention is particularly suitable for data transmission in IEEE 802.11ax networks (and future versions) where better bandwidth utilization is required.

[0275] The above has been referenced. Figures 1-5 This illustrates typical management of multi-user transmission in such a network.

[0276] A first principal embodiment of the present invention specifies that, in addition to reserving at least one communication channel of the wireless network for transmission opportunities and defining a plurality of resource units forming the communication channel, the trigger frame also includes an indicator for restricting the data to be transmitted on at least one resource unit to data having a restricted data type.

[0277] As a result, the node can determine from the trigger frame an indicator that defines the restricted data type permitted for at least one resource unit; determine from the local transfer memory data having a type corresponding to the determined restricted data type; and transmit the determined data to the access point on the resource unit.

[0278] By using such indicators, the AP can force nodes to send specific data that is particularly suitable for the design of the RU.

[0279] Two main methods are proposed for the first embodiment.

[0280] On the one hand, restricted data types define a smaller MAC packet relative to the MAC packet transmitted via a wireless network. See the following reference... Figure 8 and 9 A more detailed explanation of this method is that the AP controls the transmission of so-called small packets by sending appropriate trigger frames. Therefore, based on the amount of small packets in ongoing communication (which the AP can classify as data transmitted via ongoing communication), the AP can decide to clean up the node's transmission buffers containing small packets to reduce the node's overall contention time and the overall overhead caused by small packets.

[0281] On the other hand, restricted data types define data service types. For restricted data service types, the primary implementation references one of the four access categories defined in the 802.11 standard (i.e., AC_BK for background data, AC_BE for best-effort data, AC_VI for video applications, and AC_VO for voice applications). The following references... Figure 10a , 10bThe method is explained in more detail in section 11. As a result, the AP can force nodes to use RUs for specific service data because the AP may consider the RUs forming the composite channel to be specifically designed for this particular type of data. Again, efficient use of RUs results in sending less padding data. This improves network bandwidth utilization.

[0282] Other key embodiments of the present invention specify that, in a trigger frame in which at least one communication channel of a wireless network is reserved for transmission opportunities and multiple resource elements (which have the same duration) forming the communication channel are defined, the resource elements within the communication channel are defined to have different bandwidths.

[0283] The RUs provided in a composite channel are therefore more suitable for heterogeneous data services. By selecting the RUs to use in an appropriate manner (an example of the selection process is illustrated below), nodes generally reduce the amount of padding they transmit. This improves the utilization of network bandwidth.

[0284] For example, a node can determine whether one of its resource units matches the amount of data to be sent in the node's priority AC transmission queue, and if the determination is positive, transmit the data in the priority AC transmission queue on the matching resource unit.

[0285] The following is for reference Figures 12-14 The methods of these other main embodiments will be explained.

[0286] The main method of the first main embodiment and the methods of other main embodiments may be combined in part or in whole to increase benefits while reducing overall filler.

[0287] Figure 6 A communication device 600 of a wireless network 100 is schematically shown, wherein the communication device 600 is configured to implement at least one embodiment of the present invention. The communication device 600 may preferably be a device such as a microcomputer, workstation, or lightweight portable device. The communication device 600 includes a communication bus 613 preferably connected to the following:

[0288] • Such as a microprocessor, etc., is represented as a central processing unit 611 of a CPU;

[0289] • Read-only memory 607, denoted as ROM, is used to store computer programs used to implement the present invention;

[0290] • A random access memory 612, represented as RAM, for storing executable code of the method according to an embodiment of the present invention, and registers suitable for recording variables and parameters required to implement the method according to an embodiment of the present invention; and

[0291] • At least one communication interface 602 is connected to a wireless communication network 100, such as a wireless communication network according to the 802.11ac protocol, through which digital data packets, digital data frames, or control frames are transmitted. Under the control of a software application running in the CPU 611, frames are written from the FIFO transmit memory in RAM 612 to the transmit network interface, or frames are read from the receive network interface and written to the FIFO receive memory in RAM 612.

[0292] Optionally, the communication device 600 may also include the following components:

[0293] • A data storage component 604, such as a hard disk, is used to store a computer program for implementing a method according to one or more embodiments of the present invention;

[0294] • Disk drive 605 of disk 606, the disk drive being adapted to read data from disk 606 or write data to said disk;

[0295] • Screen 609 is used to display decoded data via keyboard 610 or any other indicating component and / or to serve as a graphical interface for the user.

[0296] The communication device 600 can be optionally connected to various peripheral devices such as a digital camera 608, wherein each peripheral device is connected to an input / output card (not shown) to supply data to the communication device 600.

[0297] Preferably, the communication bus provides communication and interoperability between the components included in or connected to the communication device 600. The representation of the bus is not limiting; in particular, the central processing unit is operable to communicate instructions directly or via components of the communication device 600 to any other component of the communication device 600.

[0298] Disk 606 may optionally be replaced by any information medium such as a compact disc (CD-ROM) (rewritable or non-rewritable), a ZIP disc, a USB key, or a memory card, and is generally replaced by an information storage component, wherein the information storage component may be read by a microcomputer or microprocessor, integrated or not integrated into the device, may be removable, and is suitable for storing one or more programs, wherein the execution of the one or more programs implements the method of the present invention to be practiced.

[0299] The executable code may optionally be stored in read-only memory 607, on hard disk 604, or on a removable digital medium such as disk 606 as previously described. According to an optional variant, the executable code of the program may be received via interface 602 through communication network 603 to be stored in one of the storage components of communication device 600, such as hard disk 604, before being executed.

[0300] Central processing unit 611 is optionally adapted to control and direct the execution of instructions or portions of the software code of the program according to the invention, wherein these instructions are stored in one of the aforementioned storage components. Upon power-up, the program stored in non-volatile memory (e.g., on hard disk 604 or in read-only memory 607) is transferred to random access memory 612 containing the executable code of the program, and registers for storing variables and parameters required to implement the invention.

[0301] In a preferred embodiment, the device is a programmable device that implements the invention using software. However, alternatively, the invention can be implemented in hardware (e.g., in the form of an application-specific integrated circuit or ASIC).

[0302] Figure 7 This is a schematic block diagram illustrating the basic structure of a communication device or node 600 (suitable for at least partially implementing one of the AP 110 or nodes 101-107 of the present invention). As shown, node 600 includes a physical (PHY) layer block 703, a MAC layer block 702, and an application layer block 701.

[0303] PHY layer block 703 (here, the 802.11 standardized PHY layer) has the following tasks: formatting, modulating or demodulating any 20MHz channel or composite channel, and thus transmitting or receiving frames such as 802.11 frames via the radio medium used, such as the medium access trigger frame TF 430 for reserving transmission slots, MAC data and management frames for interaction with conventional 802.11 stations based on a 20MHz width, and OFDMA type MAC data frames to / from the radio medium with a width smaller than 20MHz conventional (typically 2MHz or 5MHz).

[0304] PHY layer block 703 includes a CCA capability that listens for the idle or busy status of the 20MHz channel and reports the results to MAC 702 according to the 802.11 standard. When a signal with significant received signal strength is detected, an indication of channel usage is generated.

[0305] The MAC layer block or controller 702 preferably includes a MAC 802.11 layer 704 that implements conventional 802.11ax MAC operations, and additional blocks for at least partially performing the present invention. The MAC layer block 702 may optionally be implemented in software, wherein the software is loaded into RAM 612 and executed by CPU 611.

[0306] Preferably, the additional block, referred to as the MU management module, is implemented specifically for implementing all or part of the embodiments of the present invention related to node 600.

[0307] For example, in implementing the first method of the first main embodiment of the present invention (hereinafter referred to as...) Figure 8 and 9 When describing its illustrative example, the MU management module 705 includes a small packet (SP) management module 7050, wherein the small packet (SP) management module 7050 includes an AP implementation. Figure 8 The algorithm uses the "TF processor" sub-block 7051 and / or the implementation of each node. Figure 9 The algorithm uses the "RU selector" sub-block 7052.

[0308] In implementing the second method of the first main embodiment of the present invention (hereinafter referred to as...) Figure 10a , 10b When describing its illustrative example (using 11), the MU management module 705 includes an access category (AC- or service type) management module 7053, wherein the access category management module 7053 also includes an AP implementation. Figure 10a and 10b One of the algorithms uses the "TF processor" sub-block, and / or the implementation of each node. Figure 11 The algorithm uses the "RU selector" sub-block.

[0309] In implementing other main embodiments of the present invention (see reference) Figures 12-14 When describing its illustrative example, the MU management module 705 includes a bandwidth management module 7054, wherein the bandwidth management module 7054 also includes an AP implementation. Figure 12 The algorithm uses the "TF processor" sub-block and / or the implementation of each node. Figure 14 The algorithm uses the "RU selector" sub-block.

[0310] Figure 7 Typical nodes in the data include those based on the following references. Figures 8-15 Features of all embodiments of the present invention described herein.

[0311] Above the diagram, application layer block 701 runs the application, which generates and receives data packets, such as data packets for a video stream. Application layer block 701 represents all the stack layers above the MAC layer, as standardized by ISO.

[0312] Figure 8 and 9 Two flowcharts illustrate the general steps of an embodiment of the present invention that restricts data to be transmitted on at least one resource unit to data with a restricted data type (particularly small MAC packets relative to MAC packets transmitted via a wireless network). Figure 8 This is a flowchart viewed from the access point's perspective, while Figure 9 This is a flowchart from the perspective of a node. They are all applied to multi-user OFDMA uplinks in 802.11ax wireless media.

[0313] Small packages can be defined in various ways.

[0314] First, a small MAC packet can be a MAC packet with a size smaller than the predetermined maximum small packet size (i.e., the threshold). For example, the predefined maximum packet size is equal to the so-called RTS threshold parameter set for wireless networks according to the 802.11 standard. Typically, a value equal to 256 bits can be selected. The threshold size can be preset in the AP by the administrator or through the default factory settings.

[0315] In a variant, these small packets can be defined based on their overhead cost. For example, a small MAC packet could be a MAC packet with an overhead exceeding a predetermined maximum overhead (i.e., a threshold) due to the MAC header within the packet. Typical ratio values ​​are 20% or 30%.

[0316] In the third embodiment, the threshold (predetermined maximum packet size or predetermined maximum cost) can be dynamically determined using a learning mechanism as described below with reference to step 804.

[0317] Figure 8 This illustrates a typical process by which an AP generates a set of trigger frames (hereinafter also referred to as SP trigger frames or SPTFs) dedicated to small packets (SPs).

[0318] Such SP trigger frames are constructed to force nodes to send only small packets from a specific RU (preferably, all RUs defined by the SP TF or all random RUs). To achieve this, the SP TF includes an indicator specifying this restriction on small packets.

[0319] Various implementations can be envisioned.

[0320] For example, the limit indicator specified in the SP TF could be a predetermined maximum packet size or maximum cost that provides an upper limit when evaluating whether a packet is a small packet. This information can be used... Figure 15 The signaling is provided by the dedicated field 1522 shown.

[0321] In a variant, this upper limit can be predefined and known to all APs and nodes in the network. In this case, it is only necessary to indicate that the TF is SP TF for all RUs or for some RUs.

[0322] In an embodiment, the restriction indicator defines the trigger frame type, namely, SP TF. This restriction indicator indicates that all RUs defined by SP TF are limited to small packets. In other words, the trigger frame includes a single indicator for defining the same restricted data type for all resource units of at least one communication channel.

[0323] In other embodiments, restrictions can be defined at the RU level. This means that an indicator defines the RU service type: restricted to small packets, or unrestricted. This also means that the trigger frame includes an indicator for each resource unit, thereby defining various restricted data types for each resource unit. For example, see the following reference... Figure 15 As mentioned above, a dedicated RU SP or service type field can be used in the RU description to restrict the use of a specific RU in the transmission of small packets.

[0324] In a variation of the use of specific restriction indicators in the SP TF, the embodiment may specify that the duration of the TXOP is automatically made very short to implicitly allow only small packets to be transmitted. To achieve this structure, the AP will determine the duration of the transmission opportunity based on a predefined resource element bandwidth and a predetermined maximum packet size, such that at least one resource element can include only MAC packets with a packet size larger than the predetermined maximum packet size. Preferably, the predefined maximum packet size is equal to the so-called RTS threshold parameter set for the wireless network according to the 802.11 standard, and the predefined resource element width is the minimum bandwidth permitted by the 802.11 standard (2.2MHz in the case of a 20MHz channel divided into 9 RUs).

[0325] As described below, the scheduling of SP TF transmissions is determined to optimize for reducing small packet overhead. This includes determining the transmission frequency of trigger frames with restricted type indicators based on network statistics related to one or more previous transmission opportunities. This corresponds to the first steps 800–803 of the process now described.

[0326] Processing begins at step 799, where the AP determines whether a new event has occurred. If a new event occurs, step 799 determines whether the new event corresponds to the reception of a packet at the MAC layer, the expiration of the SP TF timer as described below, or any other event.

[0327] If a packet is received at the MAC layer, proceed to the next step 800, during which the AP (more generally, any node in the network can initiate a TXOP by sending a TF, in which case...) Figure 8 This can be achieved through such nodes) collecting some statistics related to the wireless network during one or more previous TXOPs.

[0328] Typical statistics include the number of nodes in the network, the number or ratio of collisions (colliding RUs), the number or ratio of used RUs, the number or ratio of unused RUs, and the distribution of packet sizes received by the AP.

[0329] The statistics can be updated whenever the AP receives a new MAC packet and decodes it.

[0330] Next, at step 801, the AP determines the maximum waiting time between two consecutive SP trigger frame transmissions.

[0331] This determination is based on updated statistics and can be performed using a pre-calculated abacus of the optimal waiting time between two consecutive SP TFs. More precisely, the abacus can plot the optimal waiting time based on the number of nodes in the network and / or based on the collision rate (the number of conflicting RUs out of the total number of RUs during the last N TXOPs).

[0332] Note that different abacuses can be used for different AP configurations: for example, one abacus for an AP used as a hotspot, one abacus for an AP used as a home set-top box, and one abacus for an AP used as an enterprise AP, etc. This is to better match the network conditions.

[0333] In a variant, the time interval between two consecutive SP TFs can be determined using a learning mechanism. For example, the AP may have received small packets from some nodes during a previous TXOP.

[0334] The scheduling interval can be modified using the ratio of RUs used and the number of small packets received, as determined during step 800. For example, if a given threshold for RU usage (typically 80%) is used, the AP can reduce the interval between two SP TFs by dividing the current time interval by the ratio (typically 2). Conversely, a low RU usage rate (less than 50%) can drive an increase in the interval between two SP TFs by multiplying the current time interval by the ratio (typically 2).

[0335] While the above suggestions include two mechanisms (abacus usage and learning mechanisms), any other mechanism can be used to adapt the scheduling of SP TF transmissions.

[0336] After determining the maximum waiting time in step 801, step 802 involves scheduling the next moment when the AP should transmit the next SPTF. Therefore, the AP adjusts the delay based on the transmission time of the previous SPTF and the maximum waiting time determined in step 801 until the next SPTF must be transmitted.

[0337] Therefore, steps 801 and 802 define the SP TF timer before sending the new SP TF.

[0338] Once the next transmission time is known, step 803 involves the AP determining when the delay / timer will expire. If the delay has just expired, the SP TF must be sent and step 804 executed. Otherwise, the SP TF timer value is modified or adjusted based on the delay determined at step 802 (if, for example, no timer is running during the startup phase, a new timer is started with a waiting value), and the system returns to waiting step 799 to wait for new packet reception.

[0339] If the SP TF timer has expired as detected by test 803 or test 799, proceed to step 804.

[0340] At step 804, the AP determines the characteristics of the SP TF: such as the number of RUs, and among these RUs, which RUs are scheduled RUs and which RUs are random RUs; the number of RUs assigned to the small packet, and among these RUs, which RUs come from all RUs; the TXOP duration; and defines the maximum size or maximum cost of the small packet for the current SP TF.

[0341] For example, an AP can adjust a predetermined maximum packet size or maximum overhead from one trigger frame to another based on network statistics related to one or more previous transmission opportunities. This information (maximum size or maximum overhead) can be specified within the AP so that nodes are aware of the upper limit for packet size.

[0342] Additionally, the AP can determine the number of resource units needed to form a communication channel based on network statistics related to one or more previous transmission opportunities. Again, this is to optimize network bandwidth usage while taking into account the needs of the nodes.

[0343] In the first embodiment, the number of resource units, the predetermined maximum packet size or maximum overhead, and the TXOP duration are fixed and known to all nodes. Step 804 retrieves only these values. For example, the maximum packet size is typically set to 256 bytes; the number of RUs dedicated to packets is equal to the total number of possible RUs in the composite channel (typically 18 RUs for a 40MHz composite channel) (typically 9 RUs for each 20MHz channel); and given the number of RUs, the TXOP duration is set to suit the predefined maximum packet size.

[0344] In a more complex second embodiment, step 804 uses a predefined abacus to obtain the values ​​of these TF features.

[0345] For example, the number of RUs dedicated to small packets can be set according to a predefined algorithm (usually by associating the number of SP RUs with the number of nodes in the cell based on the AP type (hotspot, home, enterprise, etc.).

[0346] The same mechanism can be used to determine the maximum small package size.

[0347] Furthermore, given the number of abacus-based RUs, the TXOP duration can be set to suit the maximum small package size based on the abacus.

[0348] During the evaluation testing of the access point for implementing the present invention, the abacus can be determined using a simulation model or actual measurements.

[0349] In the third embodiment, a learning mechanism is used during step 804 to determine TF features.

[0350] For example, the number of RUs dedicated to small packets can be determined based on the ratio of RUs used during the final TXOP. At step 800, the ratio of used RUs, conflicting RUs, and / or unused RUs is collected. Based on these ratios, a typical algorithm can be performed at step 804 to determine the number of RUs for small packets: if the ratio of used RUs is greater than 80%, the maximum number of SP RUs is doubled; if the ratio is less than 50%, the maximum number of SP RUs is divided by 2; otherwise, the number of SP RUs remains unchanged.

[0351] Note that the number of RUs per 20MHz channel should not exceed the maximum number of RUs (typically 9 RUs per 20MHz channel). This value (9 RUs per channel) can be used as the default value by the AP when starting up the wireless network cell.

[0352] Of course, combinations of these embodiments can be envisioned within the scope of this first embodiment: for example, a fixed maximum packet size and a dynamically determined number of SPRUs.

[0353] Following step 804, step 805 creates and sends an SP trigger frame having the characteristics determined at step 804. This SP TF transmission causes one or more nodes in the network to transmit their pending small packets in a random RU during the SP TXOP. Step 805 also starts a new SP TF timer with the current wait interval value.

[0354] Figure 9 This illustrates typical processing of node-triggered frames (particularly TFs dedicated to sets of small packets (SPs)).

[0355] At step 900, the node waits until it receives a MAC packet addressed to it.

[0356] Upon receiving such a MAC packet, the process proceeds to step 811, where the node determines whether the received packet is an SP trigger frame.

[0357] To this end, the node reads the appropriate restriction indicator in the TF at step 901 (e.g., RU service type field 1521 - see below). Figure 15 This is used to check whether at least one RU defined by TF is dedicated to small packets.

[0358] If at least one RU defined by the TF is not dedicated to small packets, the received MAC packets are processed according to the conventional mechanism, and the processing loop returns to step 900. In particular, if the AP sends a trigger frame with a very short TXOP that does not indicate a set of small packets to force the node to send only small packets, the node performs conventional processing, which means that the node will look for the appropriate (small packet) data in its transmission buffer queue.

[0359] If the received packet is an SP TF, then step 902 is executed, during which the node determines whether it has some small packets to transmit.

[0360] To this end, the node first determines the maximum packet size or cost ratio. Based on how the SPTF feature is defined as described above in step 804, this maximum packet size or cost ratio can be known in advance (as a fixed parameter), or (e.g., via field 1522 of each RU – see below) Figure 15 Transmit the maximum small packet size or overhead ratio in SP TF.

[0361] As is traditionally known, 802.11 nodes typically have multiple ordered transmission queues (or Wi-Fi Multimedia (WMM) waiting queues). These queues are usually associated with service classes or access categories as described above. Each WMM waiting queue is associated with a dynamic priority value, typically an AC backoff counter.

[0362] During step 902, the node constructs a list of small packets to be sent (SP list).

[0363] In the first embodiment, given the maximum packet size or overhead, only the first packet from the WMM transmission queue with the highest priority value (i.e., the smallest backoff counter) is considered (in the order of transmission within the queue). Therefore, a single packet is added to the list and thus transmitted via the node during the current SP TXOP.

[0364] In the second embodiment, given the maximum packet size or overhead, the first packet from each WMM transmission queue is considered. Therefore, (in the case of four 802.11 WMM queues) a maximum of four packets are added to the list and thus transmitted during the current SP TXOP.

[0365] In the third embodiment, all packets from all WMM transmission queues are considered given a maximum packet size or overhead.

[0366] In the fourth embodiment, in addition to the four existing 802.11WMM queues, the node may also maintain a fifth transmission queue, in which the node only queues small packets as they are generated based on transmissions (given a maximum small packet size or overhead). In this embodiment, all packets in the fifth transmission queue that store only small packets are considered.

[0367] Once the SP list has been built, step 903 determines whether the SP list is empty (i.e., whether there are one or more small packets to be sent?).

[0368] If the SP list is not empty, proceed to step 904. Otherwise, the processing loop returns to step 900.

[0369] At step 904, the node selects one or more RUs to send all or part of the small packets in the SP list.

[0370] In the first embodiment, using Figure 5 The random assignment process 500 selects only one RU in the SP RU, such as a random RU.

[0371] In the second embodiment, if the SP list contains multiple packets, multiple RUs (e.g., random RUs) can be selected, such as selecting one RU for each packet in the SP list. However, it is also conceivable to select multiple packets for each RU.

[0372] For illustrative purposes only, regarding the first and second embodiments described at step 902, one RU can be selected for each package. In this configuration, the TXOP duration is preferably short, so that the SP RU is designed to be more or less suited to the maximum small package size. This reduces the filling amount.

[0373] Still for illustrative purposes, with respect to the third and fourth embodiments described at step 902, multiple RUs can be selected, wherein these multiple RUs allow (as needed, in one or more RUs) the transmission of all small packets in the SP list.

[0374] If multiple RUs need to be selected, a random assignment process should be applied, for example, iteratively applying the above reference. Figure 5 The process described in step 500 is used to select all the required RUs.

[0375] After step 904, the node transmits small packets from the SP list in the selected RU at step 905.

[0376] In the first and second embodiments described in step 902 above, the small packets of the SP list can be sent on different RUs.

[0377] In the third and fourth embodiments described in step 902 above, small packets are aggregated (or cascaded) to fill the selected RU, based on the TXOP duration. When small packets are aggregated, the TXOP duration can have a conventional length because multiple small packets are sent within a single RU. Therefore, this aggregation helps reduce the amount of filling.

[0378] After step 905, the processing loop returns to step 900.

[0379] Now transferred to Figure 10a , 10b 11 and 12 use two flowcharts to illustrate the general steps of an embodiment of the invention that restricts the data to be transmitted on at least one resource unit to data with a restricted data type (particularly data of a specific service type). The service type of the data generally refers to the four access categories defined in the 802.11 standard: AC_BK for background data, AC_BE for best-effort data, AC_VI for video applications, and AC_VO for voice applications. Figure 10a and 10b This is an optional flowchart from the perspective of the access point, while Figure 11 These are flowcharts from the perspective of a node. They all apply to multi-user OFDMA uplinks in 802.11ax wireless media.

[0380] Figure 10aThis illustrates a typical process where an AP generates trigger frames (hereinafter also referred to as TT trigger frames or TT TF) that enable transmission of certain service types (TT) via nodes. In this typical process, the transmission of TT trigger frames is driven by the number of reserved RUs (hereinafter Test 1003).

[0381] During AP initialization, the number of RUs to be allocated during OFDMA transmission is predetermined at step 1000. This number can be fixed or dynamically updated. See the following reference... Figures 12-14 As described in the embodiments, various bandwidths can be envisioned for RUs within the same composite channel.

[0382] Once the number of RUs is known, step 1001 involves having the node collect some statistics related to the wireless network during one or more previous TXOPs. As described below, these statistics will be used to define a service policy, through which each RU to be retained is associated with a service type.

[0383] AP can track multiple events and statistics, such as:

[0384] - (Collision rate of RUs). This rate corresponds to the percentage of bandwidth loss caused by collisions between nodes in an 802.11 network cell.

[0385] In situations with numerous collisions, many nodes compete for access to the wireless medium simultaneously. As a result, bandwidth sharing driven by the AP can make wireless access smoother. Therefore, for example, when the collision rate exceeds a predetermined threshold, one or more TT trigger frames can be sent;

[0386] - Statistics related to service type (e.g., the four 802.11 access categories). Examples of statistics are the portion of the total data sent by a node for each service type. This statistic corresponds to network statistics related to the amount of data received in one or more previous transmission opportunities for each predefined service type.

[0387] Note that this statistical data allows the AP to assign RU service types to each RU in the TT trigger frame based on a subset of the service types in the overall service. Therefore, as network services evolve (due to evolving service requirements such as latency of various data services), the trigger frame configuration can be generated and adapted in the future.

[0388] - The queue size associated with each service type, representing the sum of all corresponding services waiting to be sent via all nodes.

[0389] As is known in the 802.11 standard, the MAC header of a transmitted packet includes a "Queue Size" field, which indicates the amount of buffered traffic of a given service type waiting in the transmission node. Based on this information, the AP can calculate global statistics related to the total queue size for each predefined service type, where the total queue size for a predefined service type is the sum of the sizes of the transmission queues associated with that predefined service type in the node. The AP can then construct associated TT trigger frames that define RUs with dedicated service types.

[0390] After step 1001, step 1002 uses statistics to dedicate one or more RUs to each specific RU service type.

[0391] If all RUs of the trigger frame are reserved for the dedicated service type (test 1003) (in the variant where a predetermined number of RUs are reserved for the dedicated service type), the trigger frame is constructed and broadcast to all nodes (1004 and 1005).

[0392] Figure 10b When sending trigger frames periodically Figure 10a Variations. In Figure 10b In this context, the transmission of TT trigger frames is no longer driven by the number of reserved RUs (see Test 1003 below), but by service policies and primarily by service delays.

[0393] Based on statistical data (including latency associated with each of the four 802.11 standard access categories [voice, video, best-effort service, background] with different latency requirements – step 1011), the AP can determine at step 1012 the time interval before sending the next TT trigger frame, depending on which service types will be associated with the RU of the TT trigger frame. Because the most critical access category is the video access category, the time interval for this type of TT trigger frame, which includes a video access RU, will be shorter than the time interval for a TT trigger frame that only includes RUs of other access categories.

[0394] In the second subprocess, the AP waits for the end of the determined time interval (test 1013) and then prepares the TT trigger frame (step 1004) before sending it (step 1005).

[0395] Figure 11 The node processes the trigger frame (especially according to...). Figure 10a Typical processing of (or 10b TT trigger frames sent via AP).

[0396] Upon receiving a TT trigger frame (i.e., a trigger frame that defines one or more RUs associated with a restricted service type) (Test 1100), the node checks whether the TT trigger frame is a TT trigger frame that indicates a single restricted service type (Test 1101).

[0397] If only one restricted service type is defined in the TT trigger frame, the node selects the corresponding access category WMM queue (step 1120).

[0398] Next, the node checks (step 1121) whether there is at least one packet ready to be sent in the selected AC WMM queue. In this way, the node selects data from the transmission queue that stores only data with the determined restricted data type.

[0399] If one or more packets exist in the selected AS WMM queue, the node, for example, by using Figure 5 The process 500 in which a random RU associated with a restricted service type is selected (step 1122) for one (or more) RUs having a restricted service type.

[0400] Next, the node transmits an MPDU frame containing packets from the selected AS WMM queue in the selected RU (step 1123) and waits for a corresponding acknowledgment from the AP indicating successful transmission (step 1124).

[0401] If two or more restricted service types (mixed service types) are defined in the TT trigger frame, the node considers the transmission queues in order of highest to lowest priority value until data is transmitted on the resource unit; and for each transmission queue considered in turn, the node determines whether the resource unit in the communication channel has a restricted service type, and if the determination is positive, transmits data from the currently considered transmission queue on the determined resource unit.

[0402] As shown in the figure, the node first selects the access category with the highest (next) priority, that is, the access category with the current minimum backoff value (step 1110).

[0403] Next, the node parses the list of RUs defined in the received TT trigger frame to select the RU with the same service type as the (next) highest priority (step 1111).

[0404] If a single RU with the (next) highest priority service type is detected, that RU is selected (step 1122).

[0405] When multiple RUs have appropriate service types, the following can be used: Figure 5The random assignment process, like process 500, is used to select a specific RU (step 1122).

[0406] Once the RU is selected, steps 1123 and 1124 above are performed to transmit data.

[0407] If the RU defined in TT TF does not have a dedicated service type that matches the (next) highest priority service type, it can be determined whether there are any unprocessed access categories remaining (step 1112). In this case, the processing loop returns to step 1110.

[0408] Because RUs are limited to specific service types, APs can efficiently adapt TXOPs to suit various types of services.

[0409] Now transferred to Figure 12 and 13 They use two flowcharts to illustrate the general steps of an embodiment of the trigger frame definition of the present invention for resource units with different bandwidths (i.e., different pitch numbers) within a communication channel.

[0410] Figure 12 This is a flowchart from the perspective of the access point, while Figure 13 These are flowcharts from the perspective of a node. They all apply to multi-user OFDMA uplinks in 802.11ax wireless media.

[0411] Figure 12 This illustrates a typical process by which an AP generates trigger frames for resource units with different RU bandwidths within a defined communication channel.

[0412] The process begins at step 1200, whereby the AP collects statistics related to services in the network cell (BSS), such as statistics related to various service types (e.g., the four 802.11 access categories—video, voice, background, and best-effort service). Examples of statistics are portions of the total data volume sent by the nodes for each service type. Other statistics may include the number of registered nodes, the modulation scheme (MCS) used by each node, the modulation scheme (MCS) used on each RU, identification of stable services (video streaming, VoIP, etc.) or random services (web browsing, control frames, etc.), and the average duration of transmissions (without padding, i.e., the duration of transmissions other than multi-user OFDMA uplink transmissions or transmissions within multi-user OFDMA uplink transmissions, obtained by excluding padding durations).

[0413] Next, at step 1210, the AP determines the number of concurrent (i.e., simultaneous) nodes and / or service types.

[0414] The AP uses the number of concurrent nodes / services to define the number of RUs to be allocated in the MU UL TXOP. For example, the larger the number of concurrent nodes / services, the larger the number of RUs.

[0415] For illustrative purposes, the number of RUs can be set to be equal to N previous TXOPs (possibly for implementation purposes). Figure 12 and 13 The method refers to the number of active nodes (i.e., data transmission nodes) in the TXOP of this embodiment. This method is used, for example, in situations where each node can only send data of a single service type. The method can also be applied to situations where nodes are forced to send only one service type of data.

[0416] In any case, the business type is associated with each RU.

[0417] Therefore, step 1202 involves retaining the RU in a TF for a specific node or service.

[0418] Note that the RU allocation in step 1202 should preferably take into account the number of concurrent data services within each node, because a corresponding number of RUs should be provided for a particular node (if possible). For example, a node may transmit two separate data services via an AP: a video stream and VoIP communication may coexist on a smartphone.

[0419] As a result, the number of RUs can be set to be equal to N previous TXOPs (possibly for implementation). Figure 12 and 13 The number of pairs (service type, transport node) detected during TXOP in this embodiment.

[0420] Therefore, step 1202 is defined as the optimal number of RUs that should be provided to meet network requirements, where each RU is dedicated to a specific service type. Note that this optimal number of RUs does not necessarily relate to the actual number of available RUs in this processing phase (meaning the optimal number can be greater than the possible number of RUs in the composite channel).

[0421] Next, steps 1203 and 1204 are performed in relation to each other and can be looped to avoid inconsistencies with the duration of the TXOP or the number of RUs and their corresponding bandwidth as defined initially, as well as inconsistencies with other cases related to the information defined initially.

[0422] At step 1203, the AP calculates the duration of the next MU UL transmission, which is the next TXOP triggered by the trigger frame to be sent.

[0423] To this end, the AP (based on statistics related to, for example, the previous N TXOPs or on the service type associated with the RU determined at step 1202) determines which types of data services are currently being transmitted in the network, and more specifically, for example, determines the resegmentation of data services according to four 802.11AC rules to adjust the TXOP duration accordingly.

[0424] More generally, the duration can be determined based on the average duration of N (integer) previous transmissions to minimize padding on average.

[0425] In a variant, the duration can also be determined to prioritize certain services. For example, if many best-effort service services have been transmitted in the RU during one or more previous TXOPs, a shorter TXOP duration can be selected, for instance, by choosing a time for transmitting the typical amount of data allowed (based on statistics obtained in 1200) for a best-effort service access category. On the other hand, if multiple video streams are in progress, a larger TXOP duration can be selected, preferably close to the TXOP limit defined for the video access category.

[0426] Without any statistics, the TXOP duration can be set to 1 / 4 of the TXOP limit duration for the video access category (AC_VI). Therefore, one RU with a tone width of 106 is allocated to video-AC_VI (or services with a large amount of data to be transmitted), one RU with a tone width of 52 is allocated to VoIP-AC_VO (or services with a moderate amount of data to be transmitted), and three RUs with 26 tones are allocated to best-effort service, background access categories (AC_BE, AC_BK), and control packets in the 20MHz channel, respectively. That is, one RU is allocated for each service category in the 20MHz band.

[0427] Once the TXOP duration is determined, the AP defines the RU characteristics of the next TXOP at step 1204.

[0428] This characteristic includes the number of RUs. Furthermore, with the TXOP duration set, other key RU characteristics to determine are the bandwidth (pitch count) of each RU forming the TF.

[0429] Based on the TXOP duration and the amount of data to be transmitted for each service type (a list of optimal RU allocations and associated data amounts), the AP determines the bandwidth of each RU (for each service type) in the form of tones (the amount of data to be transmitted is a function of the TXOP duration and RU_width_in_tones).

[0430] Next, the AP determines how to allocate the available tones on the composite channel to each RU to define the TF. The AP takes into account the RU_width_in_tones for each service type.

[0431] For example, four RU_width_in_tones (26 tones, 52 tones, 106 tones, and 242 tones) can be defined for a 20MHz channel.

[0432] For a 20MHz channel in the OFDMA MU uplink, the maximum number of RUs defined by RU_width_in_tones can be defined as follows: 9 RUs, each with 26 tones; or 4 RUs, each with 52 tones + 1 RU with 26 tones; or 2 RUs, each with 106 tones + 1 RU with 26 tones; or 1 RU with 242 tones. These are typical RU configurations in a wide set of possible RU configurations. The only limitation to mixing different RU_width_in_tones is the maximum number of tones in the channel (e.g., 242 tones for 20MHz).

[0433] Returning to the previous RU configuration example, the AP can, for example, allocate 3 RUs with 26 tones + 1 RU with 52 tones + 1 RU with 106 tones in a 20MHz channel.

[0434] If, given the RU_width_in_tones for each service type, the required number of RUs, defined as the optimal number of RUs at step 1202, exceeds the capacity of the composite channel, then prioritization is performed. Prioritization can be based on service category, prioritizing stable flows, small packets, or minimizing as much padding as possible by excluding RUs where, for these RUs, the actual transmission duration of useful data (obtained by considering the modification of the duration applied by the allocated tone number) differs significantly from the TXOP duration defined in the previous step. These RUs are those that schedule too little data for transmission.

[0435] After allocating and defining RU characteristics, (if necessary) the TXOP duration can be improved to utilize the effective RU timeslots to adjust the transmission duration.

[0436] The RU bandwidth is preferably determined based on the service type, where, as determined in step 1202 based on statistical data, the service type is dedicated. That is, the bandwidth of the resource element is determined based on statistical data related to each service type received in one or more previous transmission opportunities. Note that the above references can be used. Figure 10a , 10bThe mechanism described in section 11 explicitly assigns the RU to a specific service type in the TF.

[0437] However, in TF, this specific service type may not be signaled. This is because, by designing RUs of appropriate size, nodes will select data with the available bandwidth that is best suited to the RU, i.e., implicitly specifying the expected content (service type). For example, for large content such as video, an RU with a large bandwidth is implicitly specified.

[0438] Examples of RU bandwidth are as follows: the tone allocated by the AP to the video RU_traffic_type is more than four times the tone allocated to the background RU_traffic_type, and the tone allocated to the voice RU_traffic_type is more than twice the tone allocated to the background RU_traffic_type, to maintain the differentiation brought about by the TXOP limit parameters of the 802.11n standard. In other words, resource units associated with AC_BK and AC_BE service types have a first bandwidth (e.g., the minimum bandwidth permitted by the 802.11 standard, i.e., 2.03MHz, when a 20MHz channel is divided into 9 RUs), resource units associated with AC_VO have a bandwidth equal to twice the first bandwidth, and resource units associated with AC_VI have a bandwidth equal to four times the first bandwidth.

[0439] Because of the 1 / 4 ratio of the bandwidth between AC_BK RU and AC_VO RU, the TXOP duration is preferably set to be less than or equal to one-quarter of the TXOP limit parameter set for wireless networks according to the 802.11 standard.

[0440] For illustrative purposes, the 802.11n standard defines the following TXOP limits: 3.008 ms for the video access class (AC_VI), 1.504 ms for the voice access class (AC_VO), and 0 ms (i.e., 1 MPDU) for the background and best-effort service access classes (AC_BK and AC_BE, respectively). In implementing this embodiment, AC_BK and AC_BE can be defined as having the minimum number of tones (i.e., 26 tones), AC_VO with more than twice that number of tones (i.e., 52 tones), and AC_VI with more than four times that number of tones (i.e., 106 tones). For this configuration, the duration of the MU UL transmission, thus defining the TXOP duration, is set to 752 μs (3.008 ms / 4).

[0441] Furthermore, the bandwidth (tone number) of the RU can also depend on the modulation scheme (MCS) used by the node to reach the AP (which can also affect the transmission duration) (the MCS can be defined by each node, but is defined for each RU within each node). In other words, the bandwidth of the resource unit associated with the service type is adjusted based on the modulation scheme used by the node to transmit data with the associated service type in one or more previous transmission opportunities.

[0442] On the other hand, AP can also set MCS to minimize padding and maximize BER.

[0443] Once all RU characteristics are known, a TF can be generated and sent over the network in step 1205. See below for reference. Figure 15 Further explanation of the signaling of some RU features in TF.

[0444] Note that for random RUs, the TF should signal at least the TXOP duration, the number of random RUs, and the bandwidth (RU_width_in_tones) of each random RU. If an RU is explicitly dedicated to a specific traffic type, that traffic type should be signaled in the TF using the RU_traffic_type field. If the number of tones is fixed for each traffic type, RU_traffic_type can be replaced with RU_width_in_tones.

[0445] After the TF is sent, the AP waits for the end of the TXOP at step 1206 and sends an acknowledgment (1207) as appropriate to acknowledge the reception of all or part of the MPDU transmitted from multiple users within the OFDMA TXOP.

[0446] Preferably, the ACK frame is transmitted in a non-HT copy format in each of the 20MHz channels covered by the initial TF reservation.

[0447] Next, in step 1208, the AP updates its statistics based on the current transmissions.

[0448] Figure 13 The node processes the trigger frame (especially according to...). Figure 12 Typical processing of trigger frames sent by the AP.

[0449] At step 1300, the node detects the trigger frame of the reserved composite channel. The TF is then decoded to analyze its contents. The TF defines multiple RUs.

[0450] At step 1301, the node uses the RU characteristics specified in the TF to select one (or more) RUs. This selection can also be based on the type of service that must be transmitted.

[0451] The node selects any scheduled RU corresponding to its node_AID and determines the possible service types associated with the scheduled RU (if any). This is in order to send appropriate data in the RU.

[0452] For a random RU, the node selects one (or more) of the following random RUs:

[0453] These random RUs have a signal indicating the service type that the node (e.g., from the priority AC queue) must transmit. This is to drive the node to transmit data with the same service type as the service type associated with that resource unit on a resource unit.

[0454] Alternatively, these random RUs have a tonal bandwidth that matches as much data as a node (e.g., from a priority AC queue) as possible for a given TXOP duration. This means that a node determines whether one of its resource units matches the amount of data to be sent in the transmission queue with the highest priority value, and only if the determination is positive will the node transmit the data from the transmission queue with the highest priority value on the matching resource unit.

[0455] Nodes can also use other information from TF, such as MCS, to adjust their transmission parameters.

[0456] Next, at optional step 1302, the node can adapt or adjust the modulation scheme used to modulate the data on the resource units (potentially multiple resource units) to maximize the duration of data transmission within the transmission opportunity. This step of reducing the MCS attempts to minimize the padding associated with the TXOP duration of the next MU UL transmission. However, the same amount of data is transmitted, but with a better BER.

[0457] Next, at step 1303, the node transmits data on each of the one or more RUs selected at step 1201.

[0458] At step 1304, the node waits for confirmation from the AP.

[0459] Upon receiving a successful transmission confirmation, at step 1305, the node clears the buffered data from the AC transmission queue, thereby ending the process.

[0460] and Figure 5a Compared to the situation in the middle, Figure 14 Show Figure 12 and 13The embodiments described above offer benefits in terms of reduced fill. These benefits rely on selecting different RU configurations based on data traffic and / or node characteristics.

[0461] As shown in the figure, the AP transmits data with... Figure 5a Compared to the RU with a different bandwidth (expressed in pitch) and a shorter TXOP duration of 550', the AP modifies two dimensions of the RU (TXOP duration and bandwidth expressed in pitch) to optimize filling.

[0462] In the example of the graph, the PPDU of node STA4 is... Figure 5a and Figure 14 The data volume is the same between them. However, due to Figure 5a The RU used in it includes 26 tones, and Figure 14 The RU used in this example consists of 80 tones, thus significantly reducing the duration of TXOP (i.e., divided by approximately 3 in this example).

[0463] On the other hand, due to the reduction in TXOP duration (which is possible because of the individual RU bandwidth), transmission (within 50% of the MU UL duration) Figure 5a Many of the filled nodes (e.g., STA1, STA2, STA6) are now sending significantly reduced amounts of fill.

[0464] Note that nodes that have not yet been assigned an RU (STA3, STA7, and STA8 cannot transmit in this MU UL OFDMA transmission) will transmit in the next MU UL transmission or via Traditional Access to Radio Medium (EDCA).

[0465] Figure 12 and 13 The implementation examples can be applied to both random RUs and scheduled RUs.

[0466] Before using scheduled RUs, random RUs can be used when creating AP-driven network cells.

[0467] Initially, the initial number of random RUs can be defined using predefined statistics that define the proportion of different service types and the typical number of nodes in the cell based on AP characteristics (office, home, gym, etc.). The TXOP duration and RU bandwidth can be defined by maintaining the scaling factor of the 802.11 standard; for example, 26 tones can be defined for AC_BK and AC_BE, 52 tones for AC_VO, and 106 tones for AC_VI, while setting the MU UL transmission duration to 750 μs.

[0468] The initial random-based phase can be a temporary step used as a learning phase to learn the types of services transmitted by each node, the modulation used by each node, and / or the modulation on each RU, etc., before using the scheduling-based mode. In other words, the initial random-based phase is the phase in which nodes collect or gather statistical data as described above with reference to step 1200.

[0469] During this learning phase, the random RU can be dynamically adjusted or improved based on dynamically collected statistical data. This is to progressively modify the RU to reflect the actual business volume and the number of active registration nodes.

[0470] The result of this learning phase is that the bandwidth of each RU and the allocation of each RU to dedicated nodes can be precisely defined based on current network usage. Preferably, the selection of RU bandwidth is based on service type, but also on modulation scheme, because modulation scheme can significantly modify the transmission duration required for a fixed amount of data (e.g., modulation MCS 0 provides a bit rate of 6.5 Mbps, while modulation MCS 1 provides a bit rate of 13 Mbps).

[0471] Next, the scheduled RU mode is used when the AP explicitly assigns the designed RU to a specific node based on node requirements (e.g., node requirements transmitted during a previous TXOP; or the AP can use some service specifications provided by the nodes to define its requirements (e.g., TSPEC in HCCA)).

[0472] Figure 15 The format of "RU information element" (1510) is presented, which can be used to notify the TF of the small packet attributes and / or the TF's service type attributes and / or the RU bandwidth attributes in the form of signals.

[0473] The AP uses the “RU information element” (1510) to embed additional information within the trigger frame associated with the OFDMA TXOP. The format of the “RU information element” (1510) preferably follows the “vendor-specific information element” format as defined in the IEEE 802.11-2007 standard.

[0474] A “RU information element” (1510) is a container for one or more RU attributes (1520), each of which has a unique attribute ID for identification. The header of the RU IE can be normalized by the element ID, OUI, and OUI type value (and thus easily identifiable by nodes).

[0475] RU attribute 1520 is defined as a common format having a 1-byte RU attribute ID field, a 2-byte length field, and a variable-length attribute-specific information field.

[0476] The use of information elements within the MAC frame payload is shown for illustrative purposes only; any other format is supported.

[0477] The choice to embed additional information in the MAC payload is advantageous for maintaining traditional compliance with the media access mechanism, because any modifications made within the PHY header of the 802.11 frame will prevent any successful decoding of the MAC header by a traditional device.

[0478] As shown in the figure, the dedicated RU attributes follow the following format:

[0479] - The attribute ID is a dedicated value used to identify the "RU information". Values ​​not used in the standard can be selected (e.g., in the range 19–221). This 1-byte value is the label that initiates the "RU information".

[0480] - Defines a 2-byte length field for the attribute body.

[0481] The attribute body varies depending on the embodiment being considered. Attribute body 15a refers to... Figure 8 and 9 The small package example in the text; attribute body 15b refers to Figure 10a , 10b The business type embodiment in 11; and attribute body 15c refers to Figure 12 and 13 Implementation example of varying RU width.

[0482] In order to efficiently notify the small packet mode in the form of signals ( Figure 8 and 9 The attribute body 15a of a given RU (or the entire TF) may include:

[0483] SP type field 1521 is used to indicate whether the RU (or all RUs) is limited to small packets (or if it is SP TF). When this field is set to SP type (small packet type), it indicates to the receiving node that the RU (or all RUs) can only be used to send small packets, such as packets smaller than the maximum small packet size;

[0484] The maximum packet size field is 1522, which is used by AP to explicitly define the maximum size of the packet.

[0485] In order to efficiently notify the business type pattern in the form of signals ( Figure 10a , 10b And 11), attribute body 15b may include:

[0486] The TF_type field 1523 is used to indicate whether the trigger frame specifies the mixed mode in step 1101 (i.e., specifies a list of RUs with the same service type or a list of RUs with different mixed service types).

[0487] The RU_nb field (1524) defines the number of resource units including the composite channel. This number also indicates the number of entries in the next field.

[0488] The RU_list field 1525 lists the characteristics of each RU in the current OFDMA TXOP. Each entry in list 1525 may include the following set of fields:

[0489] The RU_index field specifies the index of the current RU in the RU list;

[0490] The RU_type field is used (only in the case of mixed mode) to specify the random mode or the scheduled mode of the RU;

[0491] The RU_traffic_type field specifies the types of services supported by the RU; and

[0492] The optional Node_AID field is used to define the node's identifier when it is a scheduled RU. This identifier can be the node's MAC address, associated identifier (AID), or a portion of the AID.

[0493] In order to efficiently notify the RU bandwidth in the form of signals ( Figure 12 and 13 The attribute body 15c of a given RU may include:

[0494] The RU_nb field (1524) defines the number of resource units including the composite channel. This number also indicates the number of entries in the next field.

[0495] The RU_list field 1525 lists the characteristics of each RU in the current OFDMA TXOP. Each entry in list 1525 may include the following set of fields:

[0496] The RU_index field specifies the index of the current RU in the RU list;

[0497] The RU_width_in_tones field specifies the number of tones for this RU;

[0498] The RU_type field is used (only in the case of mixed mode) to specify the random mode or the scheduled mode of the RU;

[0499] The RU_traffic_type field is used to specify the types of services supported by the RU;

[0500] The optional MCS field specifies the modulation scheme to be used by the RU; and

[0501] The optional Node_AID field is used to define the node's identifier when it is a scheduled RU. This identifier can be the node's MAC address, associated identifier (AID), or a portion of the AID.

[0502] All or part of the aforementioned attribute bodies can be combined to, for example, define an SP trigger frame, wherein the SP trigger frame is also a TT trigger frame of an RU with bandwidth variation.

[0503] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to these specific embodiments, and modifications within the scope of the present invention will be readily apparent to those skilled in the art.

[0504] When referring to the foregoing illustrative embodiments, which are given by way of example only and are not intended to limit the scope of the invention as defined solely by the appended claims, those skilled in the art will suggest many further modifications and variations. In particular, different features from different embodiments may be interchanged where appropriate.

[0505] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude multiple elements. The mere fact that different features are listed in mutually different dependent claims does not imply that combinations of these features cannot be used advantageously.

Claims

1. A communication device, comprising: A communication unit configured to communicate with a trigger frame, the trigger frame including information for dividing one or more communication channels in the frequency domain using multiple resource units. The trigger frame also includes information for each resource element and indicates the access category specified for that resource element in the IEEE 802.11 series of standards.

2. The communication device according to claim 1 further includes a transmitting unit configured to transmit data in response to the trigger frame.

3. The communication device according to claim 1 further includes a receiving unit configured to receive data sent in response to the trigger frame.

4. The communication device according to claim 2 or 3, wherein, The data includes multiple MAC protocol data units.

5. The communication device according to claim 1, wherein, The information indicating the access category is any one of AC_BK for background data, AC_BE for best-effort service data, AC_VI for video applications, and AC_VO for voice applications.

6. The communication device according to claim 1, wherein, The trigger frame is a trigger frame that conforms to the IEEE 802.11ax standard.

7. The communication device according to claim 1, wherein, Each of the plurality of resource units is a resource unit that conforms to the IEEE 802.11ax standard.

8. The communication device according to claim 1, wherein, The bandwidth of each resource unit in the plurality of resource units is the minimum bandwidth defined in the IEEE 802.11ax standard.

9. The communication device according to claim 1, wherein, Each of the plurality of resource units includes a plurality of subcarriers constituting orthogonal frequency division multiplexing.

10. A communication method in a communication device, comprising the following steps: Communication is performed on a trigger frame, which includes information on multiple resource units for dividing one or more communication channels in the frequency domain. The trigger frame also includes information for each resource element and indicates the access category specified for that resource element in the IEEE 802.11 series of standards.

11. The communication method according to claim 10, further comprising: Data is sent in response to the trigger frame.

12. The communication method according to claim 10, further comprising: Receive data sent in response to the trigger frame.

13. The communication method according to claim 11 or 12, wherein, The data includes multiple MAC protocol data units.

14. The communication method according to claim 10, wherein, The information indicating the access category is any one of AC_BK for background data, AC_BE for best-effort service data, AC_VI for video applications, and AC_VO for voice applications.

15. The communication method according to claim 10, wherein, The trigger frame is a trigger frame that conforms to the IEEE 802.11ax standard.

16. The communication method according to claim 10, wherein, Each of the plurality of resource units is a resource unit that conforms to the IEEE 802.11ax standard.

17. The communication method according to claim 10, wherein, The bandwidth of each resource unit in the plurality of resource units is the minimum bandwidth defined in the IEEE 802.11ax standard.

18. The communication method according to claim 10, wherein, Each of the plurality of resource units includes a plurality of subcarriers constituting orthogonal frequency division multiplexing.

19. A non-transitory computer-readable medium storing a program that, when executed by a microprocessor or computer system in a communication device, causes the communication device to perform the communication method according to any one of claims 10 to 18.

20. A wireless communication method in a wireless network, the wireless network comprising an access point and a plurality of nodes, the wireless communication method comprising the following steps at the access point: A trigger frame is sent to the node, which reserves at least one communication channel of the wireless network for transmission opportunities, and the trigger frame divides the communication channel into multiple resource elements in the frequency domain, each resource element having bandwidth. In the trigger frame, each resource element within the communication channel is associated with a corresponding access class specified in the IEEE 802.11 series of standards, and the bandwidth of the resource element depends on the corresponding access class associated with that resource element.

21. A wireless communication method in a wireless network, the wireless network comprising an access point and a plurality of nodes, the wireless communication method comprising the following steps at one of the plurality of nodes: A trigger frame is received from the access point, the trigger frame reserving at least one communication channel of the wireless network for transmission opportunities, and the trigger frame dividing the communication channel into multiple resource elements in the frequency domain, each resource element having bandwidth; as well as Data is sent from one of the plurality of resource units to the access point. In the trigger frame, each resource element within the communication channel is associated with a corresponding access class specified in the IEEE 802.11 series of standards, and the bandwidth of the resource element depends on the corresponding access class associated with that resource element.

22. The wireless communication method according to claim 20 or 21, wherein, Each resource unit is associated with an access category selected from four access categories defined in the 802.11 standard: AC_BK for background data, AC_BE for best-effort data, AC_VI for video applications, and AC_VO for voice applications.

23. The wireless communication method according to claim 22, wherein, One or more resource units associated with AC_BK and AC_BE have a first bandwidth, one or more resource units associated with AC_VO have a bandwidth equal to twice the first bandwidth, and one or more resource units associated with AC_VI have a bandwidth equal to four times the first bandwidth.

24. The wireless communication method according to claim 23, wherein, The first bandwidth is equal to the minimum bandwidth permitted by the 802.11 standard.

25. The wireless communication method according to claim 23, wherein, The plurality of resource units have the same duration, and wherein the same duration of the resource units is less than or equal to one-quarter of the TXOP limit parameter set for the wireless network according to the 802.11 standard.

26. The wireless communication method according to claim 21, wherein, Data sent from a resource unit to the access point is data belonging to the access category associated with that resource unit.

27. The wireless communication method according to claim 21, wherein, The node includes multiple transmission queues for storing data to be transmitted, each transmission queue being associated with a dynamic priority value, and the wireless communication method further includes: Determine whether one of the plurality of resource units matches the amount of data to be sent in the transmission queue with the highest priority value, and If the determination is positive, data from the transmission queue with the highest priority value is transmitted on the matching resource unit.

28. The wireless communication method according to claim 21, further comprising: The modulation scheme used to modulate the data on the resource unit is adjusted to maximize the duration of data transmission within the transmission opportunity.

29. The wireless communication method according to claim 20, further comprising: The bandwidth of the resource unit is determined based on statistics relating to data related to each access category received in one or more previous transmission opportunities.

30. The wireless communication method according to claim 20, wherein, The bandwidth of the resource unit also depends on the number of nodes registered to the access point.

31. The wireless communication method according to claim 20, wherein, The bandwidth of the resource unit associated with the access class also depends on the modulation scheme used by the node to transmit data with the associated access class in one or more previous transmission opportunities.

32. The wireless communication method according to claim 20, further comprising: The number of resource units used to form the communication channel is determined based on network statistics related to one or more previous transmission opportunities.

33. A communication device for use as an access point in a wireless network, the wireless network further comprising a plurality of nodes, the communication device for use as an access point comprising at least one microprocessor configured to perform the step of sending a trigger frame to the nodes, the trigger frame reserving at least one communication channel of the wireless network for transmission opportunities, and the trigger frame dividing the communication channel in the frequency domain into a plurality of resource elements, each resource element having bandwidth. in, In the trigger frame, each resource element within the communication channel is associated with a corresponding access class specified in the IEEE 802.11 series of standards, and the bandwidth of the resource element depends on the corresponding access class associated with that resource element.

34. A communication device in a wireless network, the wireless network including an access point and a plurality of nodes, the communication device being one of the plurality of nodes and including at least one microprocessor configured to perform the following steps: A trigger frame is received from the access point, the trigger frame reserving at least one communication channel of the wireless network for transmission opportunities, and the trigger frame dividing the communication channel into multiple resource elements in the frequency domain, each resource element having bandwidth; and Data is sent from one of the plurality of resource units to the access point. in, In the trigger frame, each resource element within the communication channel is associated with a corresponding access class specified in the IEEE 802.11 series of standards, and the bandwidth of the resource element depends on the corresponding access class associated with that resource element.

35. A non-transitory computer-readable medium storing a program that, when executed by a microprocessor or computer system in a wireless network device, causes the device to perform the wireless communication method according to any one of claims 20 to 32.

36. A computer program product comprising a program that, when executed by a microprocessor or computer system in a communication device, causes the communication device to perform the communication method according to any one of claims 10 to 18.

37. A computer program product comprising a program that, when executed by a microprocessor or computer system in a wireless network device, causes the device to perform the wireless communication method according to any one of claims 20 to 32.

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