Communication method and communication device in a communication network

Abstract

The invention relates to a communication method and a communication device in a communication network. Compared to legacy nodes, 802.11ax nodes benefit from additional medium access through multi-user uplink provided by the AP. To restore fairness of medium access, the invention proposes to update the EDCA parameters, in particular the EDCA backoff, of a node by using a penalty value each time the node successfully transmits data to the AP through an OFDMA resource unit. This is to reduce the probability of the node to re-access the communication channel through regular EDCA contention. The penalty value is preferably provided by the AP having an overview of the system and can be adjusted based on information local to the node, e.g. the amount of data transmitted or its current contention window. For example, the penalty value is added to the current value of the EDCA backoff counter after the node successfully performs an OFDMA transmission.

Description

[0001] This application is a divisional application of the invention patent application with application number 201780043091.9, application date July 12, 2017, entitled "Communication Method and Communication Device in Communication Network". Technical Field

[0002] This invention generally relates to communication networks, and more specifically, to communication networks that provide channel access to nodes through contention for transmitting data and provide secondary access to sub-channels (or resource units) for nodes to provide transmission opportunities (TXOPs) to segmented granted access points.

[0003] The present invention finds application in wireless communication networks, particularly in 802.11ax networks that provide nodes with access to 802.11ax composite channels and / or to OFDMA resource units that form, for example, 802.11ax composite channels for granting access points and allow uplink communication to be performed. Background Technology

[0004] The IEEE 802.11 MAC standard defines how wireless local area networks (WLANs) must operate at the physical and media access control (MAC) levels. Generally, 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-Sensitive Multiple Access with Collision Avoidance" (CSMA / CA) technique.

[0005] The 802.11 Media Access Protocol standard or operating mode is primarily designed for the management of communication nodes that are waiting for the wireless medium to become idle in order to attempt to access the wireless medium.

[0006] The network operating mode defined by the IEEE 802.11ac standard provides very high throughput (VHT), among other factors, due to the shift from the 2.4 GHz band, which was considered highly susceptible to interference, to the 5 GHz band, thus allowing the use of a wider 80 MHz frequency contiguous channel, two of which can be arbitrarily combined to obtain a 160 MHz channel as the operating frequency band for wireless networks.

[0007] The 802.11ac standard also tweaks control frames, such as Request to Send (RTS) and Clear to Send (CTS) frames, to allow composite channels with different and predetermined bandwidths of 20, 40, or 80 MHz, which consist of one or more adjacent communication channels within the operating band. A 160 MHz composite channel is possible by combining two 80 MHz composite channels within a 160 MHz operating band. The control frame specifies the channel width (bandwidth) of the target composite channel.

[0008] Therefore, the composite channel consists of a primary channel in which a given node performs an EDCA backoff procedure to access the medium and at least one secondary channel, each having a frequency of, for example, 20 MHz.

[0009] EDCA (Enhanced Distributed Channel Access) defines traffic categories and four corresponding access categories, which allows high-priority traffic to be treated differently compared to low-priority traffic.

[0010] EDCA can be implemented in a node using multiple traffic queues that serve data traffic with different priorities associated with corresponding queue backoff engines. To deliver data stored in the relevant traffic queues, the queue backoff engine is configured to compete for access to the composite channel using queue contention parameters (including corresponding queue backoff values).

[0011] Due to the EDCA backoff process, nodes can generally access the communication network by using a contention-type access mechanism based on queue backoff parameters, based on a calculated queue backoff counter or value.

[0012] Communication nodes use a primary channel to sense whether the channel is idle, and the primary channel can be extended to form a composite channel by using one or more secondary channels. The primary channel can also be used alone.

[0013] Assuming the operating frequency band is decomposed into a basic 20MHz channel, some secondary channels are referred to as tertiary or quaternary channels.

[0014] In 802.11ac, all transmissions and consequently any possible composite channels comprise primary channels. This is because nodes perform Carrier-Sense Multiple Access / Collision Avoidance (CSMA / CA) and Network Allocation Vector (NAV) tracking only on primary channels. Other channels are assigned as secondary channels, on which nodes only have the capability of CCA (Clear Channel Assessment), i.e., detecting the idle or busy status / condition of the secondary channel.

[0015] The problem with using composite channels as defined in 802.11n or 802.11ac (or 802.11ax) is that nodes that comply with the use of composite channels (i.e., 802.11n and 802.11ac compatible nodes or "HT nodes" representing high-throughput nodes) must coexist with legacy nodes that exist in the same wireless network and cannot use composite channels but rely solely on regular 20MHz channels (i.e., only with non-HT nodes that are compatible with, for example, 802.11a / b / g), and therefore must share the same 20MHz channels.

[0016] To address this issue, the 802.11n, 802.11ac, and 802.11ax standards provide the possibility of replicating control frames (e.g., RTS / CTS or CTS to itself or ACK frames to confirm the correct or incorrect reception of transmitted data) on each 20MHz channel in the 802.11a legacy format (referred to as "non-HT") to establish protection for requested TXOPs across the entire composite channel.

[0017] This is to inform any legacy 802.11a nodes using any 20MHz channel involved in the composite channel about ongoing communication on the 20MHz channel. As a result, legacy nodes are prevented from initiating new transmissions until the current composite channel TXOP granted to the 802.11n / ac / ax node ends.

[0018] As originally proposed by 802.11n, it provides a copy of the regular 802.11a or “non-HT” transmission to allow the simultaneous transmission of two identical 20MHz non-HT control frames on the primary and secondary channels that form the composite channel used.

[0019] This method has been extended to 802.11ac 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 a node device replicates a given control frame on a secondary 20MHz channel within the (40MHz, 80MHz, or 160MHz) operating band in a regular or “non-HT” transmission.

[0020] In practice, to request a composite channel (40MHz or greater) for a new TXOP, the 802.11n / ac node performs an EDCA backoff procedure in a single 20MHz channel, as mentioned above. In parallel, it performs channel sensing mechanisms on secondary channels, such as Clear Channel Assessment (CCA) signal detection, to detect one or more idle secondary channels (channel condition / state is "idle") during the PIFS interval before the start of a new TXOP (i.e., before any queue backoff counters expire).

[0021] Recently, the Institute of Electrical and Electronics Engineers (IEEE) officially approved the 802.11ax task group as the successor to 802.11ac. The main goal of the 802.11ax task group is to seek to improve the data speed of wireless communication devices used in densely deployed scenarios.

[0022] The latest developments in the 802.11ax standard seek to optimize the use of combined channels across multiple nodes in wireless networks with access points (APs). In practice, typical content involves significant amounts of data, such as data related to high-definition audiovisual live and interactive content. Furthermore, it is well known that the performance of the CSMA / CA protocol used in the IEEE 802.11 standard degrades rapidly in dense WLAN scenarios with increasing node numbers and traffic.

[0023] In this context, multi-user (MU) transmission has been considered to allow multiple simultaneous transmissions to / from different users in both the downlink (DL) and uplink (UL) directions during the transmission opportunities granted to the AP. In the uplink, MU transmission can mitigate the probability of collisions by allowing multiple nodes to transmit simultaneously.

[0024] To practically implement this multi-user transmission, it has been proposed, for example, to divide the allocated channel into multiple sub-channels, also known as resource units (RUs), shared by multiple users in the frequency domain, based on Orthogonal Frequency Division Multiple Access (OFDMA) technology. Each RU can be defined by several tones, and an 80MHz channel contains up to 996 available tones.

[0025] OFDMA is a multi-user variation of OFDM that has emerged as a new key technology for improving efficiency in advanced infrastructure-based wireless networks. It combines OFDM at the physical layer with Frequency Division Multiple Access (FDMA) at the MAC layer, allowing different subcarriers to be assigned to different nodes to improve concurrency. Adjacent subcarriers often experience similar channel conditions and are therefore grouped into subchannels: an OFDMA subchannel, or RU, is thus a group of subcarriers.

[0026] As currently envisioned, this OFDMA subchannel has a finer granularity than the original 20MHz channel bandwidth. Typically, a 2MHz or 5MHz subchannel can be envisioned as the minimum width, thus defining, for example, nine subchannels or resource units within a single 20MHz channel.

[0027] OFDMA's multi-user feature allows an AP to assign different RUs to different nodes to increase contention. This can help reduce contention and collisions within an 802.11 network.

[0028] In contrast to downlink OFDMA, where an AP can directly send multiple data to multiple stations (supported by specific instructions within the PLCP header), a triggering mechanism has been adopted for the AP to trigger uplink communication from various nodes.

[0029] To support multi-user uplinks, i.e. uplink transmissions to 802.11ax access points (APs) during the preemptive TXOP period, the 802.11ax AP must provide signaling information to legacy nodes (non-802.11ax nodes) to set their NAVs and to provide signaling information to 802.11ax nodes to determine the allocation of resource units (RUs) provided by the AP.

[0030] It has been proposed that the AP send a trigger frame (TF) to the 802.11ax node to trigger uplink communication.

[0031] The document IEEE 802.11-15 / 0365 proposes that an Access Point (AP) sends a "Trigger" frame (TF) to request the transmission of an Uplink (UL) Multi-User (OFDMA) PPDU from multiple nodes. The TF defines the Resource Unit (RU) offered by the AP to the nodes. In response, the nodes transmit an ULMU (OFDMA) PPDU as a direct response to the trigger frame. All transmitters can transmit data simultaneously, but using disjoint sets of RUs (i.e., frequencies used in the OFDMA scheme), resulting in less interference-prone transmission.

[0032] The bandwidth or width of the target composite channel is signaled in the TF frame, which means adding a value of 20, 40, 80, or 160 MHz. If appropriate, the TF frame is transmitted on a primary 20 MHz channel and repeated (copied) on each of the other 20 MHz channels forming the target composite channel. As described above, for the repetition of the control frame, it is expected that each nearby legacy node (non-HT or 802.11ac node) receives the TF on its primary channel and then sequentially sets its NAV to the value specified in the TF frame. This prevents these legacy nodes from accessing the target composite channel during TXOP.

[0033] Resource Units (RUs) can be reserved for specific nodes. In this case, the Access Point (AP) indicates the node that reserved the RU in the Transfer Function (TF). This RU is called a scheduled RU. The indicated node does not need to compete for access to the scheduled RU reserved for it.

[0034] To improve system efficiency regarding unmanaged traffic to the AP (e.g., uplink management frames from associated nodes, unassociated nodes intending to reach the AP, or simply unmanaged data traffic), the AP can propose resource units (RUs) to 802.11ax nodes via contention-based access. In other words, a resource unit (RU) can be randomly accessed by more than one node (from the group of nodes registered with the AP). This RU is called a random RU and is indicated as such in the TF (Transaction Function). The random RU can serve as the basis for contention among nodes willing to access the communication medium to send data.

[0035] An exemplary random resource selection process is defined in the document IEEE 802.11-15 / 1105. According to this process, each 802.11ax node maintains a dedicated backoff engine (hereinafter referred to as OFDMA or RU (for resource unit) backoff engine) using RU contention parameters (including RU backoff values) to compete for access to one of the random RUs. Once its OFDMA or RU backoff value reaches zero (e.g., it is subtracted from the value defined therein for the random RU at each new TF-R frame), the node becomes eligible for RU access and thereby randomly selects one RU from all the random RUs defined in the received trigger frame. It then uses the selected RU to transmit data for at least one traffic queue.

[0036] As can be clearly seen from the above, multi-user uplink media access schemes (or OFDMA or RU access schemes) allow for a reduction in the number of collisions caused by simultaneous media access attempts. Furthermore, since the media access cost is shared among several nodes, it also reduces overhead associated with media access. Therefore, OFDMA or RU access schemes appear to be significantly more effective than conventional EDCA contention-based media access schemes (in the context of high-density 802.11 cells) (in terms of media usage).

[0037] Although OFDMA or RU access schemes appear to be more efficient, EDCA access schemes must also survive in order to coexist with OFDMA or RU access schemes.

[0038] For example, this is due to the existence of legacy 802.11 nodes that are unaware of OFDMA or RU access schemes.

[0039] 802.11ax nodes should also have the opportunity to gain access to the medium via conventional EDCA contention-based medium access, for example, to send data to another node (i.e., for traffic different from uplink traffic to the AP). Therefore, both medium access schemes, EDCA and OFDMA / RU, must coexist.

[0040] This coexistence has drawbacks.

[0041] For example, 802.11ax nodes and legacy nodes have the same media access probability when using the EDCA access scheme. However, 802.11ax nodes have additional media access opportunities using the MU uplink or OFDMA or RU access schemes.

[0042] As a result, access to the medium is not entirely fair between 802.11ax nodes and legacy nodes. Summary of the Invention

[0043] The broad objective of this invention is to provide improved and fairer communication methods and devices in communication networks. The communication network comprises multiple nodes and access points to which some nodes (e.g., 802.11ax nodes) have registered, and all nodes (including 802.11ax and legacy nodes) share the physical medium of the communication network.

[0044] The present invention has been designed to overcome one or more of the above-mentioned limitations, and in particular to provide a communication method that provides fair access for both legacy nodes (which do not implement the second access scheme) and enhanced nodes (e.g., 802.11ax nodes that implement the second access scheme).

[0045] The present invention may also optionally facilitate the use of a second and more efficient access scheme (MU uplink in 802.11ax or OFDMA or RU access scheme) to improve the efficiency of 802.11 cells while maintaining a good level of fairness regarding legacy nodes. This may result in more efficient use of network bandwidth (for RUs) with limited collision risk.

[0046] This invention can be applied to any communication network, such as a wireless network, where, within a given transmission opportunity, resource units (arbitrary random RUs or scheduled RUs, or both) are provided for the MU uplink to the AP. An RU is a subchannel of one or more communication channels. A communication channel is the basic channel through which a node performs sensing to determine whether it is idle or busy.

[0047] This invention is particularly suitable for data uplink transmission from a node to an AP in an IEEE 802.11ax network (and future versions), in which case OFDMA is used to access the RU. Embodiments of this invention can also be applied to communication networks between nodes (without an AP) and in any communication network other than 802.11ax, as long as it provides two competing access schemes (one for the communication channel and the other for RUs, etc., that can access simultaneously).

[0048] Against this backdrop, embodiments of the present invention provide a communication method in a communication network comprising multiple nodes, wherein at least one node includes a channel access module, the channel access module being configured to compete for access to at least one communication channel of the communication network by using channel contention parameters in order to transmit data (e.g., locally stored on the accessed communication channel); and

[0049] The method includes the following at the node:

[0050] Within the transmission opportunities granted to other nodes on the communication channel, data (locally stored) is transmitted through access resource units provided (i.e., defined) by another node. Therefore, the resource unit forms part of these transmission opportunities granted to the other nodes; and

[0051] In response to transmitting data through the access resource unit, the current value of at least one channel contention parameter is modified or updated to a (penalty) value to reduce the probability of a node competing for access to the communication channel through the channel access module.

[0052] Therefore, this invention restores fairness in communication networks. This is achieved by penalizing nodes that effectively use the multi-user uplink through the accessed RU for conventional channel access schemes (to reduce the probability of using that scheme to access the communication channel). In effect, legacy nodes thus gain more opportunities to access the communication channel compared to nodes that also implement the RU access scheme.

[0053] This invention also promotes the use of resource units for nodes implementing multi-user uplinks, rather than conventional EDCA access schemes, resulting in better network efficiency. This is because the penalty applied to conventional channel access schemes increases the use of resource units, thereby increasing the sharing of medium access costs among nodes.

[0054] Accordingly, embodiments of the present invention provide a communication device for forming nodes in a communication network including multiple nodes, the communication device for forming nodes comprising:

[0055] A channel access module configured to compete for access to at least one communication channel of a communication network by using channel contention parameters in order to transmit data locally stored on an access communication channel.

[0056] A communication module configured to transmit locally stored data via an access resource unit provided by another node within a transmission opportunity granted to other nodes on a communication channel; and

[0057] A controller configured to modify the current value of at least one channel contention parameter of the channel access module to a penalty value in response to data transmission by the data transmission module through the access resource unit, thereby reducing the probability of a node accessing the communication channel through contention of the channel access module.

[0058] This device offers the same advantages as the method described above.

[0059] From the perspective of the access point, embodiments of the present invention provide a communication method in a communication network, the communication network including an access point and a plurality of nodes registered to the access point, at least one node including a channel access module, the channel access module being configured to compete for access to at least one communication channel of the communication network by using channel contention parameters in order to transmit locally stored data on the accessed communication channel; and

[0060] The method includes, at the access point:

[0061] Data is received from one or more nodes through any one of the communication channels accessed by one or more nodes and through resource units accessed by one or more nodes, with each resource unit being provided by the access point to the one or more nodes within the transmission opportunity granted to the access point on the communication channel.

[0062] The penalty value is determined based on the history of the received data; and

[0063] A determined penalty value is sent to at least one node to drive the node to update the current value of at least one channel contention parameter to the penalty value based on the penalty value sent after the node sends data through the access resource unit, thereby reducing the probability of the node accessing the communication channel through its channel access module.

[0064] By applying a penalty value to the node's channel contention parameters, the access point can effectively drive nodes to use the communication network more equitably. Furthermore, an appropriate penalty value can help promote the effective use of the RU access scheme compared to conventional channel access schemes.

[0065] Accordingly, embodiments of the present invention provide a communication device forming an access point in a communication network including an access point and multiple nodes, wherein at least one node includes a channel access module, the channel access module being configured to compete for access to at least one communication channel of the communication network by using channel contention parameters in order to transmit locally stored data on the accessed communication channel; and

[0066] The communication equipment that forms the access point includes:

[0067] A communication module configured to receive data from one or more nodes via any one of a communication channel accessed by one or more nodes and a resource unit accessed by one or more nodes, wherein each resource unit is provided by the access point for one or more nodes within the transmission opportunities granted to the access point on the communication channel.

[0068] A penalty determination module configured to determine penalty values ​​based on the history of received data;

[0069] The communication module is further configured to send a determined penalty value to at least one node to update the current value of at least one channel contention parameter to the penalty value based on the penalty value sent after the node sends data through the access resource unit, thereby driving the node to reduce the probability of the node competing to access the communication channel through its channel access module.

[0070] The device that forms the access point provides the same advantages as the method described above.

[0071] Optional features of embodiments of the present invention are defined in the appended claims. Some of these features are explained below with reference to a method, while they can be converted into system features specific to any device according to embodiments of the present invention.

[0072] For example, a channel access module may include one or more queue backoff engines and associated traffic queues for serving data traffic with different priorities. Each queue backoff engine uses queue contention parameters (including corresponding queue backoff values) to transmit data contention stored in the associated traffic queues for access to at least one communication channel. These can be conventional EDCA traffic queues and corresponding engine-driven contention on the medium. In this case, the channel contention parameters are those queue contention parameters.

[0073] In addition, a node may include an RU access module, which is separate from the channel access module and is configured to manage access to at least one resource unit provided by other nodes within the transmission opportunities granted to other nodes on the communication channel in order to transmit locally stored data on the accessed resource unit.

[0074] In practice, the RU access module can handle both scheduled RUs and random RUs provided in the trigger frame. Scheduled RUs are detected simply by reading the contents of any received trigger frame. Regarding random RUs of interest, the RU access module may include an RU backoff engine, separate from the queue backoff engine (or more generally from the channel access module), using RU contention parameters, including RU backoff values, to compete for access to at least one random resource unit provided by other nodes within the transmission opportunities granted to other nodes on the communication channel in order to transmit data stored in arbitrary flow queues on the accessed random resource unit. The RU backoff value is typically decremented at each newly received trigger frame by the number of random RUs declared in the received TF. This effectively implements contention for random RUS.

[0075] In this embodiment, both the current value and the penalty value are non-zero. In practice, the penalty value is made greater than the current value in order to statistically delay the penalized node's subsequent access to the medium.

[0076] In other embodiments, the method further includes: at a node, receiving a trigger frame from other nodes (typically access points) in the communication network, the trigger frame reserving transmission opportunities on the communication channel for other nodes and defining resource elements RU that form the communication channel including the resource elements of access.

[0077] The received trigger frame includes a penalty value to be applied to the current value to obtain the penalty value for the queue contention parameter.

[0078] This configuration enables other nodes (typically APs) to effectively drive the node while using the communication network more equitably, and promotes the use of more efficient RU access schemes (due to shared access costs).

[0079] In another embodiment, the method further includes: at a node, periodically receiving beacon frames from an access point, each beacon frame broadcasting network information about the communication network to multiple nodes.

[0080] The received beacon frame includes a (default) penalty value to be applied to the current value to obtain a penalty value for the queue contention parameter.

[0081] This allows access points, which typically have an overview of the entire network, to periodically set effective initial penalty values ​​for nodes.

[0082] In a particular embodiment, the method further includes: at a node, in order to obtain a final penalty value to be applied to the current value to obtain a penalized value for the queue contention parameter, modifying the penalty value contained in the trigger frame using the penalty value contained in the trigger frame. This illustrates how the penalty value to be applied can evolve over time, assuming instructions are provided by another node, preferably the access point. It can be noted that the penalty value can be easily reset at each new beacon frame. Of course, other periodic resets can be used.

[0083] In other specific embodiments, the received beacon frame or the received trigger frame includes multiple penalty values ​​associated with a corresponding data type, and the method further includes selecting a penalty value at the node from the multiple penalty values ​​based on the data type associated with the traffic queue corresponding to the channel contention parameter to be modified. In practice, certain specific queue contention parameters may be associated with traffic queues with different priorities (e.g., EDCA). Therefore, this embodiment enables the adjustment of penalties for different data types.

[0084] In other embodiments, modifying the current value of the channel contention parameter to a penalty value depends on the amount of data transmitted in the accessed resource unit. It is understood that nodes transmitting varying amounts of data will be penalized to different degrees.

[0085] Therefore, this configuration advantageously avoids severely penalizing nodes when nodes only send a reduced amount of data via the OFDMA / RU access scheme.

[0086] In other embodiments, the modified channel contention parameters include a queue backoff value, which decreases over time by the node to allow access to the communication channel upon reaching zero (typically used for sending data storage in the corresponding traffic queue). This configuration allows nodes to be penalized immediately.

[0087] For example, modifying the queue backoff value involves adding a penalty value to the queue backoff value. This means that due to the countdown of the queue backoff value, nodes will wait longer before accessing the communication channel (corresponding to the amount of penalty value added).

[0088] Based on specific characteristics, the added penalty value is a function of the size of the contention window from which the queue backoff value was initially selected. This stipulation ensures that, given the corresponding current probability, the penalty may have a similar effect on each traffic queue that could be modified. In practice, the larger the contention window size, the higher the queue backoff value overall. Therefore, for fairness, it is preferable to make the impact on the traffic queue proportional to the contention window.

[0089] More precisely, the added penalty value can be the competition window size (labeled CW) and the lower bound CW of the range from which to select the competition window size. min The ratio is a function of the ratio between them. This provision advantageously takes into account the impact of network load on the estimation of channel contention parameters. In fact, the above ratio essentially reflects the number of consecutive collisions during a node's previous access period (since CW typically doubles with each collision, therefore, from CW...). min (At the beginning), and thus reflects a type of network load.

[0090] In some embodiments, the modified channel contention parameters include the size of the contention window from which the queue backoff value is initially selected, and the queue backoff value decreases over time by the node to access the communication channel after reaching zero. Since only the newly selected queue backoff value will be affected by the penalty-based modification, this configuration will penalize the node in the future.

[0091] In a specific embodiment, the modified channel contention parameters include the lower bound CW. min and / or upper bound CW max Both define the range of choices from which to select the size of the competing window. This also helps in penalizing nodes in the future.

[0092] In other specific embodiments, modifying the competition window size or its lower or upper bound includes multiplying it by a penalty value.

[0093] In some embodiments of the present invention, the resource unit for accessing data transmitted thereon is a random resource unit, and access is performed by competition using separate RU contention parameters (separate from channel contention parameters).

[0094] In other embodiments, the access resource unit on which data is transmitted is a scheduling resource unit, and the scheduling resources are allocated to the node by the access point.

[0095] Of course, some nodes can connect to a scheduled RU, while other nodes can simultaneously connect to a random RU. Therefore, the penalty according to the present invention can occur simultaneously at different nodes, rather than when different types of RUs are connected.

[0096] In some embodiments, other nodes are access points to the communication network to which the nodes are registered. This provision advantageously utilizes the central location of the access points. In effect, the access points have an overview of the entire network and can therefore effectively drive the nodes used for the penalty process.

[0097] In some embodiments, modifying the current value to the penalized value is in response to successful data transmission on the accessed resource unit. Therefore, a node will only be penalized for further regular EDCA access if transmission on the RU is successful.

[0098] Therefore, this regulation tends to support media access schemes that work for the nodes under consideration (because the transmission was successful). This improves the overall efficiency of the network.

[0099] In a particular embodiment, the channel access module includes traffic queues for serving data traffic with different priorities, and the method further includes selecting at least one of the traffic queues from which data is to be transmitted. This selection step is necessary because OFDMA access to the resource element is not linked to a specific traffic queue.

[0100] Based on specific characteristics, a traffic queue can be selected, including one of the following:

[0101] Select the flow queue with the lowest associated queue backoff value;

[0102] Randomly select a non-empty traffic queue from the traffic queues;

[0103] Select the traffic queue that stores the largest amount of data (i.e., the largest load);

[0104] Select the non-empty traffic queue with the highest associated traffic priority;

[0105] Select and match the non-empty traffic queue associated with the data type of the resource unit on which the selected data is to be transmitted.

[0106] According to another specific feature, a node (e.g., via the RU access module described above) includes an RU backoff value to compete for access to at least one random resource unit provided by another node within a transmission opportunity granted to another node on the communication channel, and the method may further include, at the node, decrementing the RU backoff value based on the number of random resource units defined in the received trigger frame after receiving the trigger frame.

[0107] In addition, the method may also include decrementing the queue backoff value at the node for each basic time unit when the communication channel is detected as idle (if present in the channel access module).

[0108] In other embodiments, the method further includes: at a node, when no more data to be sent to the access point remains in the traffic queue after the data transmission step, clearing the queue backoff value corresponding to the traffic queue. The queue backoff value associated with a non-empty traffic queue is reduced by the node over time to access the communication channel after reaching zero. Of course, this operation can be performed on each traffic queue that becomes empty after the data transmission step.

[0109] Regarding the operation of the node at the access point, the embodiment specifies that determining the penalty value includes updating the current penalty value based on the ratio of bandwidth usage of the resource units accessed by the node to transmit data to the access point to the total bandwidth of the communication channel and resource units used by the node. Bandwidth usage can be viewed as the amount of data sent by the node, and therefore transmitted on the accessed resource units and possibly on the accessed communication channel. In other words, the access point considers whether to adjust the penalty value to be imposed by the node by using resource units to transmit a high proportion of received data.

[0110] This allows the AP to finely adjust the penalty value applied to nodes to favor one or the other of the conventional EDCA access scheme and OFDMA / RU access scheme. This is because the aforementioned ratio essentially reflects the efficiency of the penalty. Therefore, based on this, the AP can determine whether the penalty is currently sufficient given other criteria (e.g., node density in the cell) and can thus adjust the penalty value to be sent.

[0111] In this embodiment, the current penalty value is increased whenever the evaluation of the ratio is less than a predetermined target threshold. This is to penalize nodes when using the Regular Channel Access (EDCA) scheme, thereby promoting the use of the MU uplink through the resource element.

[0112] In a particular embodiment, the current penalty value is reduced whenever the evaluation of the ratio exceeds a predetermined target threshold. This is to, in turn, reduce the likelihood of collisions in the MU uplink facilitated by the RU.

[0113] In some embodiments, the decision to send a penalty value to at least one node depends on the ratio between the number of access resource units experiencing a collision and the total number of resource units that a node accesses to send data to the access point. Similarly, the access point can thus facilitate the use of the MU uplink until the risk of collision becomes too high.

[0114] In some other embodiments, the penalty value is transmitted in a trigger frame that reserves the transmission opportunity for the access point on the communication channel and defines the resource unit RU that forms the communication channel, or in a beacon frame that broadcasts network information about the communication network to multiple nodes.

[0115] In some other embodiments, the access point determines the penalty value for each type of data from the history of received data of the same data type; and

[0116] Send multiple penalty values ​​associated with various data types to at least one node.

[0117] Another aspect of the invention relates to a communication system having multiple nodes, at least one of which is a communication device forming a node as defined above.

[0118] In particular, the communication system may also include the communication devices that form access points as defined above.

[0119] 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 communication device via a communication network, causes the communication device to perform any of the methods defined above.

[0120] Non-transitory computer-readable media may have similar features and advantages to those described above and below regarding the methods and apparatus.

[0121] Another aspect of the invention relates to a communication method in a communication network, the communication network comprising, substantially as shown in the accompanying drawings. Figure 10 or Figure 11a or Figure 10 and 11a The above and the multiple nodes shown in the figure.

[0122] 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 completely hardware embodiment, a completely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, which are generally referred to herein as “circuit,” “module,” or “system.” Furthermore, the invention can take the form of a computer program product embodied in any tangible medium having an expression of computer-usable program code embodied in the medium.

[0123] Since this invention can be implemented in software, it can be embodied as computer-readable code for provision 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, acoustic signals, magnetic signals, or electromagnetic signals (e.g., microwave or RF signals). Attached Figure Description

[0124] Further advantages of the 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 and with reference to the following drawings.

[0125] Figure 1 This diagram illustrates a typical wireless communication system that can implement embodiments of the present invention;

[0126] Figure 2a and 2b The IEEE 802.11e EDCA is shown, which relates to the access category;

[0127] Figure 3 This demonstrates 802.11ac channel allocations supporting channel bandwidths of 20MHz, 40MHz, 80MHz, or 160MHz known in the art;

[0128] Figure 4 An example of an 802.11ax uplink OFDMA transmission scheme is shown, in which the AP issues a trigger frame to reserve a transmission opportunity for an OFDMA subchannel (resource element) on an 80MHz channel known in the art.

[0129] Figure 5 A schematic representation of a communication device or communication station according to an embodiment of the present invention is shown;

[0130] Figure 6 A schematic representation of a wireless communication device according to an embodiment of the present invention is shown;

[0131] Figure 7 An exemplary transport block of a communication node according to an embodiment of the present invention is shown;

[0132] Figure 8 The main steps performed by the MAC layer of a node when receiving new data to be transmitted are illustrated using a flowchart in an embodiment of the present invention.

[0133] Figure 9 The steps for accessing the medium based on a conventional EDCA media access scheme in an embodiment of the present invention are illustrated using a flowchart.

[0134] Figure 10The flowchart illustrates the steps of accessing a resource unit based on an RU or OFDMA access scheme after receiving a trigger frame defining an RU, according to an embodiment of the present invention.

[0135] Figure 11a The general steps for an access point to calculate and send one or more penalty values ​​according to an embodiment of the present invention are illustrated using a flowchart; and

[0136] Figure 11b This shows the structure of a trigger frame as defined in the 802.11ax standard. Detailed Implementation

[0137] The invention will now be described with reference to specific, non-limiting exemplary embodiments and the accompanying drawings.

[0138] Figure 1 This diagram illustrates a communication system in which several communication nodes (or stations) 101–107 exchange data frames on a radio transmission channel 100 of a wireless local area network (WLAN) under the management of a central station or an access point (AP) 110 to which the nodes have registered. The radio transmission channel 100 is defined by an operating frequency band consisting of a single channel or multiple channels forming a composite channel.

[0139] Access to the shared radio medium for transmitting data frames is based on CSMA / CA technology, which is used to sense carriers and avoid collisions by separating concurrent transmissions in space and time.

[0140] Carrier sensing in CSMA / CA is performed by both physical and virtual mechanisms. Virtual carrier sensing is achieved by transmitting control frames to reserve the medium before data frames are transmitted.

[0141] Next, the source or transmission node, including the AP, first attempts to sense, through physical mechanisms, that the medium has been idle for at least one DIFS (representing the DCF inter-frame spacing) period before transmitting the data frame.

[0142] 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.

[0143] To access the medium, a node starts a countdown backoff counter, which is designed to expire after several time slots randomly selected within a contention window [0, CW], where CW (an integer) is also called the contention window and defines the upper bound (or contention window size) of the backoff selection interval. This backoff mechanism or process, also known as a channel access scheme, is the basis of a collision avoidance mechanism that reduces the probability of collisions on a shared channel by randomly delaying transmission time. After the backoff period (i.e., when the backoff counter reaches zero), if the medium is idle, the source node can send data or control frames.

[0144] One problem with wireless data communication is that the source node cannot listen in while transmitting, thus preventing it from detecting data corruption caused by channel fading, interference, or collisions. The source node remains unaware of corrupted data frames and continues to transmit frames unnecessarily, wasting access time.

[0145] Therefore, if a frame is successfully received, the CSMA / CA collision avoidance mechanism provides the receiving node with a positive acknowledgment (ACK) of the transmitted data frame to notify the source node that no corruption of the transmitted data frame has occurred.

[0146] ACK is transmitted at the end of the reception of a data frame, immediately following a period of time called Short Interframe Spacing (SIFS).

[0147] If the source node does not receive an ACK within the specified ACK timeout period, or detects the transmission of a different frame on the channel, it can be inferred that the data frame is lost. In this case, it typically reschedules the frame transmission according to the backoff process described above.

[0148] To improve the collision avoidance efficiency of CSMA / CA, a four-way handshake mechanism is optionally implemented. One implementation is known as RTS / CTS switching as defined in the 802.11 standard.

[0149] RTS / CTS switching includes exchanging control frames during a transmission opportunity known as TXOP in the 802.11 standard to reserve the radio medium before transmitting data frames, thereby protecting data transmission from any further collisions. The four-way CTS / RTS handshake mechanism is well-known and will not be described further here. For further details, refer to the standard.

[0150] The RTS / CTS four-way handshake mechanism is very effective in terms of system performance, especially for large frames, because it reduces the length of messages involved in the contention process.

[0151] In detail, assuming perfect channel awareness at each communication node, a collision might only occur when two (or more) frames are transmitted in the same time slot after the DIFS (Digital Distance Between Frames), or when their own backoff counters reach zero almost simultaneously. If both source nodes use the RTS / CTS mechanism, the collision can only occur for RTS frames. Fortunately, because a CTS response is quickly determined, this collision is detected early by the source nodes.

[0152] Figure 2a and Figure 2bThis illustrates the IEEE 802.11e EDCA (Electronic Data Class Assisted Communication) for improving Quality of Service (QoS). In the original DCF standard, communication nodes included only one transmission queue / buffer. However, because subsequent data frames could not be transmitted until the transmission / retransmission of the previous frame was complete, the delay in the transmission / retransmission of the previous frame prevented the communication from achieving QoS.

[0153] IEEE 802.11e has already overcome this deficiency by providing enhanced Quality of Service (QoS) to make more efficient use of the wireless medium.

[0154] The standard relies on a coordination function called the Hybrid Coordination Function (HCF), which has two operating modes: Enhanced Distributed Channel Access (EDCA) and HCF Controlled Channel Access (HCCA).

[0155] EDCA enhances or extends the functionality of the original access DCF method: EDCA is designed to support priority traffic similar to DiffServ (Differentiated Services), which is a protocol used to specify and control network traffic by class so that certain types of traffic are given priority.

[0156] EDCA is a primary channel access scheme or mechanism in WLANs due to its distributed and easily deployable nature. To enable nodes to transmit locally stored data on accessed communication channels, this scheme uses channel contention parameters to compete for access to at least one communication channel in the network.

[0157] The aforementioned shortcomings of unsatisfactory QoS due to frame retransmission delays are addressed by utilizing multiple transmission queues / buffers.

[0158] QoS support in EDCA is achieved by introducing four Access Classes (ACs), which in turn introduce four corresponding transport / traffic queues or buffers (310). Of course, another number of traffic queues can be considered.

[0159] Each AC has its own traffic queue / buffer to store the corresponding data frames to be transmitted over the network. Data frames entering from the upper layers of the protocol stack, i.e., MSDUs, are mapped to one of the four AC queues / buffers and are thus input into the mapped AC buffer.

[0160] Each AC also has its own set of channel contention parameters, or "queue backoff parameters," which are associated with priority values, thereby defining higher or lower priority traffic for the MSDU. Therefore, multiple traffic queues exist to serve data traffic with different priorities.

[0161] This means that each AC (and its corresponding buffer) acts as an independent DCF contention entity, including its own queue backoff engine 311. Therefore, each queue backoff engine 311 is associated with a corresponding traffic queue and is used to compete for access to at least one communication channel by using queue contention parameters, including their respective calculated queue backoff values, in order to transmit data stored in each traffic queue on the accessed communication channel.

[0162] As a result, ACs within the same communication node compete with each other to access the wireless medium and obtain transmission opportunities, for example, by using conventional EDCA or channel contention schemes as explained above.

[0163] By setting different queue backoff parameters between ACs, such as different contention window parameters (CW) min CW max Different arbitration inter-frame spacing (AIFS) and different transmission opportunity duration limits (TXOP_Limit) are used to differentiate services between ACs.

[0164] Using EDCA, high-priority traffic has a higher chance of being sent than low-priority traffic: nodes with high-priority traffic wait a little less time on average before sending their packets than nodes with low-priority traffic (low CW).

[0165] exist Figure 2a Four AC buffers (210) are shown in the figure.

[0166] Buffers AC3 and AC2 are typically reserved for real-time applications (e.g., voice or video transmission). They have the highest priority and the second-lowest priority, respectively.

[0167] Buffers AC1 and AC0 are reserved for best-effort and background traffic, respectively. They have the second-lowest priority and the lowest priority, respectively.

[0168] According to the mapping rules, each data unit (MSDU) arriving at the MAC layer from a higher layer (e.g., the link layer) with priority is mapped to the AC. Figure 2b An example of the mapping between the eight priorities of the traffic class (user priority or UP, 0-7 according to IEEE 802.1d) and the four ACs is shown. The data frame is then stored in the buffer corresponding to the mapped AC.

[0169] When the backoff process of the traffic queue (or AC) ends, the MAC controller of the transmission node (below) Figure 6 (See attached figure 604) The data frame is transferred from the traffic queue to the physical layer for transmission over the wireless communication network.

[0170] Since ACs operate simultaneously when accessing the wireless medium, it is possible for two ACs on the same communication node to terminate their backoff simultaneously. In this case, the virtual conflict processor (212) of the MAC controller selects the AC with the highest priority among the conflicting ACs (e.g., ...). Figure 2b (as shown), and abandon the transmission of data frames from the AC with lower priority.

[0171] Then, the virtual conflict handler commands the lower-priority ACs to start backoff operations again by using the increased CW value.

[0172] The QoS resulting from the use of AC can be signaled in MAC data frames, for example in the QoS control field contained in the header of an IEEE 802.11e MAC frame.

[0173] To meet the growing demand for faster wireless networks to support bandwidth-intensive applications, 802.11ac is targeting greater bandwidth delivery through multi-channel operation. Figure 3 This shows the 802.11ac channel allocation that supports composite channel bandwidths of 20MHz, 40MHz, 80MHz, or 160MHz.

[0174] IEEE 802.11ac introduces support for a limited number of predefined subsets of 20MHz channels to form unique predefined composite channel configurations that can be reserved for data transmission by any 802.11ac node on a wireless network.

[0175] The predetermined subsets are shown in the figure, and correspond to channel bandwidths of 20MHz, 40MHz, 80MHz, and 160MHz, respectively, compared to 20MHz and 40MHz supported only by 802.11n. In practice, the 20MHz component channels 300-1 to 300-8 are connected to form a wider communication composite channel.

[0176] In the 802.11ac standard, the channels of each predetermined 40MHz, 80MHz or 160MHz subset are continuous within the operating frequency band, meaning that holes (lost channels) are not allowed to be generated in the composite channel according to the order in the operating frequency band.

[0177] The 160MHz channel bandwidth consists of two 80MHz channels, which may or may not be frequency-contiguous. The 80MHz and 40MHz channels are respectively composed of two 40MHz and 20MHz channels that are frequency-adjacent or adjacent. However, the invention can have embodiments with any composition of channel bandwidth, i.e., including only adjacent channels or formed by non-adjacent channels within the operating frequency band.

[0178] Nodes are granted TXOPs via the Enhanced Distributed Channel Access (EDCA) mechanism on a "primary channel" (300-3). In practice, for each composite channel with bandwidth, 802.11ac designates one channel as "primary," meaning it is used to compete for access to the composite channel. A primary 20MHz channel is shared by all nodes (STAs) belonging to the same basic set—that is, managed by the same local access point (AP) or registered to the same AP.

[0179] However, to ensure that no other legacy nodes (i.e., not belonging to the same set) use the secondary channel, it is assumed that the control frames (e.g., RTS frames / CTS frames) of the reserved composite channel are copied on each of the 20MHz channels of such composite channel.

[0180] As mentioned earlier, 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, the 5GHz band will certainly tend to saturate even if each wireless LAN cell uses 20 or 40MHz of bandwidth.

[0181] The development of the 802.11ax standard seeks to improve the efficiency and use of wireless channels in dense environments.

[0182] In this regard, multi-user (MU) transmission features can be considered, allowing multiple simultaneous transmissions to / from different users in both the downlink (DL) and uplink (UL) directions. In the uplink, MU transmission can be used to mitigate the probability of collisions by allowing multiple nodes to transmit simultaneously.

[0183] To practically implement such multi-user transmission, a technique based, such as Orthogonal Frequency Division Multiple Access (OFDMA), has been proposed to divide the permitted 20MHz channel (300-1 to 300-4) into sub-channels 410 (basic sub-channels), also known as subcarriers or resource units (RUs), which are shared by multiple users in the frequency domain.

[0184] refer to Figure 4 This is shown.

[0185] OFDMA's multi-user feature allows an AP to assign different RUs to different nodes to increase contention. This can help reduce contention and collisions within an 802.11 network.

[0186] Unlike the MU downlink OFDMA, which allows the AP to send multiple data directly to multiple nodes (supported by specific indications within the PLCP header), the AP employs a triggering mechanism to trigger MU uplink communication from various nodes.

[0187] To support MU uplink transmission (during the preemptive TxOP), the 802.11ax AP must provide signaling information to legacy nodes (non-802.11ax nodes) to set their NAV, and to provide signaling information to 802.11ax nodes to determine resource unit allocation.

[0188] In the following description, the term legacy refers to non-802.11ax nodes, meaning 802.11 nodes that do not support prior technology OFDMA communication.

[0189] like Figure 4 As shown in the example, the AP sends a trigger frame (TF) 430 to the target 802.11ax node. The bandwidth or width of the target composite channel is signaled in the TF frame, meaning that a value of 20, 40, 80, or 160 MHz is signaled. The TF frame is transmitted on a primary 20 MHz channel and copied (repeated) on each of the other 20 MHz channels forming the target composite channel. As mentioned above, for the copying of the control frame, it is expected that each neighboring legacy node (non-HT or 802.11ac node) receives the TF on its primary channel and then sets its NAV to the value specified in the TF frame. This prevents these legacy nodes from accessing the target composite channel during TXOP.

[0190] Based on the AP's decision, the trigger frame TF can define multiple resource units (RUs) 410 or "random RUs" that can be randomly accessed by nodes in the network. In other words, the random RUs specified or allocated by the AP in the TF can serve as the basis for competition among nodes willing to access the communication medium to send data. A collision occurs when two or more nodes attempt to transmit simultaneously on the same RU.

[0191] In this context, the trigger frame is referred to as the Trigger Frame for Random Access (TF-R). The TF-R can be transmitted by the AP to allow multiple nodes to perform UL MU (Uplink Multi-User) random access to obtain RUs for their UL transmissions.

[0192] In addition to random RUs or their alternatives, trigger frames (TFs) can also specify scheduling resource units. An AP can reserve scheduled RUs for certain nodes where these nodes do not need to contend for access to such RUs. Such RUs and their corresponding scheduling nodes are indicated in the trigger frame. For example, to explicitly indicate which nodes are allowed to use each scheduled RU, a node identifier, such as an association ID (AID) assigned to each node after registration, is added in association with each scheduled RU.

[0193] A random RU can be identified using an AID equal to 0.

[0194] OFDMA's multi-user feature allows an AP to assign different RUs to different nodes to increase contention. This can help reduce contention and collisions within an 802.11 network.

[0195] exist Figure 4 In the example, each 20MHz channel (400-1, 400-2, 400-3 or 400-4) is subdivided in the frequency domain into four sub-channels or RU 410, typically each 5MHz in size.

[0196] Of course, the number of RUs used to divide a 20MHz channel may not be four. For example, two to nine RUs could be set up (so the size of each RU is between 10MHz and about 2MHz).

[0197] Once a node uses a RU to send data to the AP, the AP responds with an acknowledgment (not shown in the diagram) to acknowledge the data on each RU.

[0198] The document IEEE 802.11-15 / 1105 provides an exemplary random allocation process that nodes can use to access random RUs indicated in a TF. This random allocation process, known as the RU contention scheme, is managed by a dedicated RU access module separate from the aforementioned channel access module, and is configured to manage access to at least one resource unit offered by another node (typically an AP) within transmission opportunities granted to other nodes on the communication channel in order to transmit locally stored data on the accessed resource unit. Preferably, the RU access module includes an RU backoff engine separate from the queue backoff engine, which uses RU contention parameters, including calculated RU backoff values, to compete for access to the random RU.

[0199] In other words, the RU contention scheme is based on a new backoff counter within the 802.11ax node, hereinafter referred to as OFDMA or RU backoff counter / value (or OBO), which allows dedicated contention when accessing a random RU to send data.

[0200] Each node STA1 to STAn is a transmitting node for receiving AP. Therefore, each node has an active RU backoff engine separate from the queue backoff engine, which is used to calculate the RU backoff value (OBO). This RU backoff value is used to compete for access to at least one random resource unit that is divided into transmission opportunities granted on the communication channel in order to transmit data stored in any flow queue AC.

[0201] The random allocation process includes: a first step, for a node with multiple nodes having an active RU backoff value (OBO), determining a random sub-channel or RU available for contention in the communication medium from the trigger frame; a second step, verifying whether the value of the active RU backoff value (OBO) of the considered node is not greater than the number of randomly detected available RUs; and a third step, if the verification is successful, randomly selecting a random RU from the randomly detected available RUs used for data transmission. If the second step is not verified, a fourth step (instead of the third step) is performed to reduce the number of RUs detected as available by decreasing the RU backoff value (OBO).

[0202] As shown in the figure, some resource units may not be used (410u) because no node with a RU backoff value OBO less than the number of available random RUs randomly selects one of these random RUs, while others conflict (e.g., 410c) because two of these nodes randomly select the same RU.

[0203] Compared to conventional EDCA access schemes, the MU uplink media access scheme has proven to be highly effective. This is because the number of collisions generated by simultaneous media access attempts and the overhead caused by media access are both reduced.

[0204] However, the EDCA access scheme and the MU uplink OFDMA / RU access scheme must coexist, especially allowing legacy 802.11 node access media, and even allowing 802.11ax nodes to initiate communication with nodes other than the AP.

[0205] While the standalone EDCA access scheme provides fair access to the medium at all nodes, its association with the MU uplink OFDMA / RU access scheme introduces a shift in fairness. This is because 802.11ax nodes have additional opportunities to transmit data within resource units provided within the transmission opportunities granted to another node, particularly the AP.

[0206] This drift should be minimized as much as possible.

[0207] A broad objective of this invention is to provide improved and fairer communication methods and devices in communication networks.

[0208] To achieve this, the present invention proposes updating the channel (or EDCA) contention parameters, specifically the EDCA backoff counter, with a penalty value after the node has taken advantage of the additional opportunity to transmit data on the resource unit. Therefore, the penalty value applied to the channel contention parameters can reduce the probability of a node re-accessing the communication channel through conventional (EDCA) contention.

[0209] The penalty value is preferably provided by the AP with a system overview and can be adjusted based on local information of a given node (e.g., the amount of data sent or the current contention window).

[0210] For example, after a node successfully performs an OFDMA transmission, a penalty value is added to the current value of the EDCA backoff counter. Therefore, the probability of re-accessing the communication channel is adjusted, typically reduced, each time a node successfully accesses a resource element and transmits data through it.

[0211] Therefore, this invention is applied when a node transmits locally stored data on an access resource unit provided (to the node) by another node (e.g., an AP) within a transmission opportunity granted to another node on a communication channel. According to the invention, in response to transmitting data through the access resource unit, the node modifies the current value of at least one channel contention parameter to a penalized value to reduce the probability of the node gaining access to the communication channel through contention.

[0212] Another aspect of embodiments of the invention is applied to the AP side to effectively drive nodes by modifying their current values ​​of at least one channel contention parameter to a penalized value based on a penalty value sent after each node transmits data through the access resource unit. This is also to reduce the probability that these nodes access the communication channel through contention, as they use additional opportunities to transmit data provided by resource units that divide the transmission opportunities granted to the AP.

[0213] In use, the AP receives data from one or more nodes on any of the communication channels accessed through one or more nodes and on resource units accessed by one or more nodes, with each resource unit provided by the access point within the transmission opportunities granted to the access point on the communication channel.

[0214] Therefore, the AP can build statistics about the history of received data and then determine the penalty value based on the history of received data.

[0215] In order to drive the node as described above, the AP sends the determined penalty value to the node.

[0216] Figure 5 A communication device 500 configured to implement at least one embodiment of the present invention is schematically shown. The communication device 500 is preferably a device such as a microcomputer, workstation, or lightweight portable device. The communication device 500 includes a communication bus 513, which is preferably connected to:

[0217] • Central processing unit 511, such as a microprocessor, shown as a CPU;

[0218] • Read-only memory 507, shown as ROM, is used to store a computer program for implementing the present invention;

[0219] • Random access memory 512, shown as RAM, is used to store executable code of the method according to an embodiment of the present invention, and registers adapted to record variables and parameters required to implement the method according to an embodiment of the present invention;

[0220] • At least one communication interface 502 connected to a radio communication network 100 (e.g., a wireless communication network according to the 802.11ax protocol) that transmits digital data packets or frames or control frames. These frames are written from a FIFO transmit memory in RAM 512 to the network interface for transmission, or read from a network interface for reception and writing to a FIFO receive memory in RAM 512, under the control of a software application running in CPU 511.

[0221] Optionally, the communication device 500 may also include the following components:

[0222] • Data storage means 504, such as a hard disk, for storing computer programs for implementing the methods according to one or more embodiments of the present invention;

[0223] • A disk drive 505 for disk 506, the disk drive being adapted to read data from disk 506 or write data to said disk;

[0224] • Screen 509 is used to display decoded data and / or serve as a graphical interface with the user via keyboard 510 or any other pointing means.

[0225] The communication device 500 can optionally be connected to various peripherals such as, for example, a digital camera 508, each peripheral connected to an input / output card (not shown) to supply data to the communication device 500.

[0226] Preferably, the communication bus provides communication and interoperability between various elements contained in or connected to the communication device 500. The representation of the bus is not limited; in particular, the central processing unit is operable to transmit instructions directly to or through another element of the communication device 500 to any element of the communication device 500.

[0227] Disk 506 may optionally be replaced by any information medium such as, for example, a rewritable or non-rewritable optical disc (CD-ROM), a ZIP disk, a USB key, or a memory card, and generally by an information storage means that can be read by a microcomputer or microprocessor, integrated or not integrated into the device, may be removable, and is adapted to store the execution of which enables the implementation of one or more programs according to the method of the invention.

[0228] The executable code can be stored arbitrarily in read-only memory 507, hard disk 504, or removable digital media such as disk 506 as described above. According to an optional variation, the executable code of the program can be received via interface 502 through communication network 503 and stored in one of the storage devices of communication device 500, such as hard disk 504, before execution.

[0229] The central processing unit 511 is preferably adapted to control and direct the execution of instruction or software code portions of one or more programs according to the invention, the instructions being stored in one of the aforementioned storage means. Upon power-up, one or more programs stored in non-volatile memory (e.g., on hard disk 504 or read-only memory 507) are transferred to random access memory 512, which subsequently contains executable code for one or more programs, and registers for storing variables and parameters required to implement the invention.

[0230] In a preferred embodiment, the device is a programmable device that uses software to implement the invention. However, as an alternative, the invention can be implemented in hardware (e.g., in the form of an application-specific integrated circuit or ASIC).

[0231] Figure 6 This is a block diagram schematically illustrating the architecture of a communication device or node 500 (particularly one of nodes 100-107) suitable for at least partially implementing the present invention. As shown, node 500 includes a physical (PHY) layer block 603, a MAC layer block 602, and an application layer block 601.

[0232] The task of PHY layer block 603 (here, the 802.11 standardized PHY layer) is to format frames, modulate or demodulate frames from any 20MHz channel or composite channel, and thereby transmit or receive frames on the radio medium 100 in use. These frames can be 802.11 frames, such as the medium access trigger frame TF430 for defining resource units in an granted transmission opportunity, MAC data and management frames based on a 20MHz width for interaction with legacy 802.11 stations, and OFDMA type MAC data frames with a width smaller than the 20MHz legacy (generally 2MHz or 5MHz) to / from the radio medium.

[0233] The MAC layer block or controller 602 preferably includes a MAC 802.11 layer 604 that implements conventional 802.11ax MAC operations and an additional block 605 for at least partially performing the present invention. The MAC layer block 602 may optionally be implemented in software, which is loaded into RAM 512 and executed by CPU 511.

[0234] Preferably, an additional block called EDCA parameter update module 605 implements the part of the invention concerning node 500, namely, modifying one or more channel / EDCA contention parameters to penalty values ​​after transmitting data through the access resource unit in the case of a transmission node, or calculating the penalty value to be transmitted to the node in the case of an access point.

[0235] As described below, in order to provide management of the channel access module of the processing queue backoff engine and the RU access module of the processing RU backoff engine, the MAC 802.11 layer 604 and the EDCA parameter update module 605 interact with each other.

[0236] At the top of the diagram, application layer block 601 runs the application that generates and receives data packets (such as data packets for a video stream). Application layer block 601 represents all stack layers above the MAC layer, as standardized by ISO.

[0237] Embodiments of the invention will now be illustrated using various exemplary embodiments. Although the presented example uses a trigger frame 430 sent by the AP (see... Figure 4 This mechanism enables multi-user uplink transmission, but an equivalent mechanism can be used in a centralized environment or in an ad-hoc environment (i.e., without an AP). This means that the operations described below with reference to an AP can be performed by any node in an ad-hoc environment.

[0238] These embodiments are described primarily by considering OFDMA resource units within the context of IEEE 802.11ax. However, the application of the invention is not limited to the IEEE 802.11ax context.

[0239] Furthermore, this invention does not necessarily rely on the use of the MU access scheme described in 802.11ax. Any other RU access scheme that defines a backup medium access scheme allowing nodes to access the same medium simultaneously can also be used.

[0240] Figure 7 An exemplary transmission block of a communication node 500 according to an embodiment of the present invention is shown.

[0241] As described above, the node includes a channel access module and a possible RU access module, both implemented in MAC layer block 602. The channel access module includes:

[0242] Multiple traffic queues 210 are used to serve data traffic with different priorities;

[0243] Multiple queue backoff engines 211 are configured to transmit data stored in various traffic queues. Each queue backoff engine 211 is associated with a corresponding traffic queue that uses queue contention parameters, specifically for calculating the corresponding queue backoff value, to compete for access to at least one communication channel. This is an EDCA access scheme.

[0244] To transmit data stored in any traffic queue within an OFDMA RU, the RU access module includes an RU backoff engine 700, separate from the queue backoff engine. This RU backoff engine 700 is used to calculate RU backoff values ​​using RU contention parameters, specifically RU backoff values, to compete for access to an OFDMA resource unit defined in a received TF (e.g., sent by the AP). The RU backoff engine 700 is associated with a transmission module called an OFDMA multiplexer 701. For example, when the RU backoff value OBO, described below, reaches zero, the OFDMA multiplexer 701 is responsible for selecting the data to be transmitted from AC queue 210.

[0245] The conventional AC queue backoff register 211 drives the media access request along the EDCA protocol (channel contention scheme), while in parallel, the RU backoff engine 700 drives the media access request to the OFDMA multi-user protocol (RU contention scheme).

[0246] Since these two competing schemes coexist, the source node implements a media access mechanism with conflict avoidance based on the calculation of the backoff value:

[0247] - The queue backoff counter value corresponds to the number of time slots a node waits for after detecting that the communication medium is idle, but before accessing the medium. This is EDCA;

[0248] - The RU backoff counter value (OBO) corresponds to the number of idle random RUs detected by the node before accessing the medium, after granting a TXOP to the AP or any other node on the composite channel formed by RUs. This is OFDMA. An example of changing the countdown OBO based on the number of idle random RUs can be based on a time-based countdown.

[0249] In an embodiment of the present invention, the EDCA parameter update module 605 is responsible for modifying the current value of at least one channel contention parameter (backoff 211 or contention window of AC queue 210) of the channel / EDCA access module of each node to a penalized value, so as to reduce the probability of the node accessing the communication channel through the channel access module.

[0250] When a node transmits data using the MU UL transmission scheme (i.e., through one or more resource units) (preferably successfully), the EDCA parameter update module 605 applies a penalty value to one or more of the EDCA contention parameters.

[0251] This is to promote the use of the MU UL mechanism, while restoring fairness regarding media access opportunities between legacy nodes and 802.11ax nodes, as the latter benefit from additional access opportunities through access resource units.

[0252] Generally, penalty values ​​can be pre-defined or obtained from the AP, or even calculated locally. For example, the AP can send penalty values ​​in the TF or beacon frame, either directly applied or calculated locally, to obtain the final penalty value to be applied to the current contention parameter value. Penalty values ​​can also be transmitted or calculated with... Figure 2b Each of the traffic types shown corresponds to several penalty values. The local calculation of the final penalty value may involve the amount of data sent by the node to trigger an update of the contention parameters. This is to avoid severe penalties when a node sends a reduced amount of data only via the OFDMA scheme. It may also involve the current value of the contention window local to the node under consideration.

[0253] Finally, the penalty value can be applied, for example, by adding it to one or more current EDCA backoff values, and / or, for example, by applying it as a multiplicative factor to the local contention window. Of course, the penalty value used may differ when applied to an EDCA backoff value and when applied to a local contention window.

[0254] Figure 8 The main steps performed by the MAC layer 602 of node 500 when receiving new data to be transmitted are illustrated using a flowchart. It shows a typical FIFO feed in the context of 802.11.

[0255] Initially, no traffic queue 210 stores the data to be transmitted. Therefore, no queue backoff value 211 is calculated. The corresponding queue backoff engine or the corresponding AC (Access Class) is said to be inactive. Once the data is stored in the traffic queue, the queue backoff value is calculated (based on the corresponding queue backoff parameters), and the associated queue backoff engine or AC is said to be active.

[0256] When a node has data ready to be transmitted over the medium, the data is stored in one of the AC queues 210, and the associated backoff 211 should be updated.

[0257] In step 801, new data is received from a local application running on the device (e.g., from application layer 601), from another network interface, or from any other data source. The new data is ready to be sent by the node.

[0258] At step 802, the node determines which AC queue 210 the data should be stored in. This is typically done by checking the TID (Traffic Identifier) ​​value attached to the data (according to...). Figure 2b(The matching shown).

[0259] Next, step 803 stores the data in a defined AC queue. This means that the data is stored in an AC queue with the same data type as the data itself.

[0260] At step 804, a standard 802.11 AC backoff calculation is performed via the queue backoff engine associated with the determined AC queue.

[0261] If the determined AC queue was empty only before the storage in step 803 (i.e., the AC was initially inactive), then a new queue backoff value needs to be calculated for the corresponding backoff counter.

[0262] Then, the node calculates the queue backoff value equal to a random value selected from the range [0, CW] + AIFS, where CW is the current value of the CW for the considered access class (defined in the 802.11 standard and updated, for example, according to some embodiments of the invention described in step 1080 below), and AIFS is an offset value that depends on the AC of the data (all AIFS values ​​are defined in the 802.11 standard) and is designed to implement the relative priority of different access classes. CW is selected from the range [0, CW] + AIFS. min CW max The selected congestion window value, here, is the boundary CW. min and CW max It all depends on the access category being considered.

[0263] As a result, AC activity is activated.

[0264] The above parameters CW, CW min CW max AIFS and backoff values ​​form channel or queue contention parameters associated with each AC. They are used to set the relative priority of the access medium for different types of data.

[0265] Some of these parameters typically have fixed values ​​(e.g., CW). min CW max And AIFS), while the other two parameters (CW and backoff value) evolve with time and media availability.

[0266] If necessary, step 804 may also include calculating the RU backoff value OBO. The RU backoff engine 700 needs to be calculated if it is inactive (e.g., because there was no data in the traffic queue until the previous step 803) and if new data to be addressed to the AP has been received.

[0267] The RU backoff value OBO can be calculated in a similar manner to the EDCA backoff value, i.e., using dedicated RU contention parameters, such as a dedicated contention window [0, CWO] and a selection range [CWO]. min CWO max ].

[0268] Note that some embodiments may provide a distinction between data that can be transmitted via resource units (i.e., data compatible with OFDMA transmission) and data that cannot be transmitted via resource units. Such a decision can be made during step 802, and corresponding markers can be added to the stored data.

[0269] In this case, the RU backoff value OBO is calculated only if the newly stored data is marked as compatible with OFDMA transmission.

[0270] Immediately following step 804, Figure 8 The process is over.

[0271] Once the data is stored in the AC queue, nodes can directly access it via the following reference. Figure 9 The EDCA access scheme shown below or refer to the following: Figure 10 As shown, the access medium is accessed via one or more trigger frames through resource units provided by the AP.

[0272] Figure 9 The steps for accessing the medium based on a conventional EDCA media access scheme are illustrated using a flowchart.

[0273] Steps 900–920 describe the routine waiting introduced in the EDCA mechanism to reduce collisions on the shared radio medium. In step 900, node 500 senses the medium waiting for it to become available (i.e., the detected energy is below a given threshold on a primary channel).

[0274] When the medium becomes idle during the backoff time slot or "DIFS period", step 910 is executed, in which node 500 decrements all active (non-zero) AC[] queue backoff counters 211 by one. In other words, for each basic time unit DIFS in which the communication channel is detected as idle, the node decrements the queue backoff value.

[0275] Next, at step 920, node 600 determines whether at least one of the AC backoff counters has reached zero.

[0276] If no AC queue backoff reaches zero, node 500 waits for another backoff slot (typically 9 μs) and thus loops back to step 900 to sense the medium again during the next backoff slot.

[0277] If at least one AC queue backoff reaches zero, step 930 is executed, in which node 500 (more precisely, virtual conflict processor 212) selects the active AC queue with a zero queue backoff counter and the highest priority.

[0278] At step 940, an appropriate amount of data is selected from the chosen AC for transmission.

[0279] Next, at step 950, if, for example, an RTS / CTS exchange has been successfully executed to grant a TXOP, node 500 initiates an EDCA transmission. Therefore, node 500 transmits selected data on the medium during the granted TXOP.

[0280] Next, at step 960, node 500 determines whether the EDCA transmission has ended; in this case, step 970 is executed.

[0281] At step 970, node 500 updates the contention window (CW) of the selected traffic queue based on the transmission status (positive or negative ACK, or no ACK received). Typically, if a transmission fails, node 500 doubles the value of CW until CW reaches the maximum value defined by the 802.11 standard and depending on the AC type of the data. max On the other hand, if the EDCA transmission is successful, the contention window CW is set to the minimum CW, which is also defined by the 802.11 standard and depends on the AC type of the data. min .

[0282] Next, if the traffic queue selected after the EDCA data transmission is not empty, then similar to step 804, a new associated queue backoff counter is randomly selected from [0, CW].

[0283] This is the end. Figure 9 The process.

[0284] According to an embodiment of the invention, the current value of at least one channel contention parameter includes, for example, a queue backoff counter value and / or an AC contention window and / or even a CW. min and / or CW max This can be modified to a penalized value. This is to reduce the probability of nodes competing for access to the communication channel via EDCA, in order to restore fairness that might have been drifted due to the additional media access opportunities provided to some nodes through the OFDMA access RU.

[0285] Therefore, a non-zero current value can be modified into a downgraded, and thus also non-zero, penalized value.

[0286] This modification occurs when a node transmits data stored locally on an access resource unit that forms part of a transmission opportunity granted to another node (typically an AP) over a communication channel. In other words, as now referenced... Figure 10 As described, during OFDMA access for the RU.

[0287] Figure 10 The steps for accessing a resource unit based on an RU or OFDMA access scheme are illustrated using a flowchart.

[0288] At step 1010, the node determines whether to receive a trigger frame from an access point in the communication network. This trigger frame reserves a transmission opportunity granted to the access point on the communication channel and defines the resource unit RU that forms the communication channel. If so, the node analyzes the content of the received trigger frame.

[0289] At step 1020, the node determines whether it can transmit data via one of the RUs defined in the received trigger frame. This determination may involve one or both of two conditions, particularly regarding the type of RU.

[0290] By analyzing the contents of the received Transfer Message (TF), the node determines whether the defined RU is a scheduling resource unit assigned to the node by the access point. This is achieved by searching for its own AID in the received TF, which will be associated with the RU of the specific schedule used for the transmission.

[0291] Furthermore, by analyzing the contents of the received TF, the node determines whether one or more random RUs are defined in the TF, i.e., RUs that compete for access using dedicated RU contention parameters (including the OBO value 700 mentioned above). In this case, the node also determines whether its current OBO value 700 allows the selection of a random RU (especially if OBO 700 is less than the number of random RUs in the TF).

[0292] If a scheduled RU is assigned to a node or the latter is allowed to access a random RU, the node determines the size of the random / scheduled (one or more) RUs to use and performs step 1030. Otherwise, the node decrements the RU backoff value OBO 700 based on the number of random resource units defined in the received trigger frame, and the process ends when the node cannot access any RU defined by the received TF.

[0293] At step 1030, the node selects at least one of the traffic queues 210 from which to select the data to be transmitted, and adds the data of the selected queues to the transmission buffer until the amount of data reaches the size of the selected resource unit to be used.

[0294] This can involve various criteria for selecting the current traffic queue.

[0295] For example, this can be accomplished through the following process:

[0296] Select the traffic queue 210 with the lowest associated queue backoff value. Therefore, the selection of the traffic queue depends on the value of EDCA backoff 211;

[0297] Randomly select a non-empty traffic queue from the traffic queues;

[0298] Select the traffic queue that stores the largest amount of data (i.e., the largest load);

[0299] Select the non-empty traffic queue with the highest associated traffic priority (given) Figure 2b (As shown in the AC category);

[0300] Select and match the non-empty flow queue associated with the data type of the resource unit on which the selected data is to be transmitted (the data type can be defined in a dedicated field of the TF when the AP defines the RU).

[0301] Next, at step 1040, the node stores an information item indicating the amount of data selected from the current traffic queue for transmission in the RU. For example, the node then updates the list of transmission queues by inserting the amount of data selected from the current traffic queue.

[0302] This transmit queue list can be implemented using a table containing the amount of data placed into the transmit buffer for each traffic queue.

[0303] This information item can be used to adjust the way certain competing parameters are modified according to the teachings of the present invention. Embodiments relying on such an information item are described below.

[0304] At step 1050, the node determines whether the amount of data stored in the transmit buffer is sufficient to fill the selected resource unit.

[0305] If not, there is still space in the resource unit for additional data. Therefore, the process loops back to step 1030, during which another traffic queue is selected using the same selection criteria. In this way, the transmission buffer is gradually filled until the selected resource unit size is reached.

[0306] In cases where changes are made to avoid mixing data from two or more traffic queues (i.e., selecting data for the selected RU from a single traffic queue), padding data can be added to fully populate the selected RU. This is to ensure that the RU has energy that can be detected by legacy nodes throughout its lifespan.

[0307] Once the transmit buffer is full for the selected RU, step 1060 initiates the transmission of the OFDMA data stored in the transmit buffer to the AP. OFDMA transmission is based on the OFDMA subchannels and modulation defined in the received trigger frame, specifically in the RU definition.

[0308] Next, once the transmission has been performed, and preferably after a successful transmission (i.e., receiving an acknowledgment from the AP), step 1070 determines one or more penalty values ​​to be applied to one or more EDCA parameters of one or more traffic queues, so as to modify it or them to one or more penalized values.

[0309] At step 1070, several embodiments can be envisioned to determine one or more penalty values.

[0310] In the first embodiment, the received trigger frame (at step 1010) includes one or more penalty values ​​that are applied by the node to one or more current values ​​to obtain one or more queue contention parameters (e.g., AC backoff values). Therefore, the penalty value is retrieved from the TF.

[0311] The following reference Figure 11a and 11b This describes an exemplary embodiment in which the AP calculates one or more such penalty values ​​and adds them to the TF.

[0312] In a variation of the first embodiment, the received beacon frame includes one or more (default) penalty values ​​to be applied by the node to one or more current values ​​to obtain one or more queue contention parameters (e.g., AC backoff values).

[0313] In practice, the 802.11 standard defines a beacon frame as a frame that broadcasts 802.11 network information to all nodes in a communication network. Beacon frames are transmitted periodically, approximately every 100 milliseconds, during which time a node or access point (AP) may attempt to access the network multiple times. Therefore, a node considering this scenario periodically receives such beacon frames from an access point, and each beacon frame broadcasts network information about the communication network to multiple nodes.

[0314] Since the AP can send several trigger frames between two consecutive beacon frames, the embodiment can provide a default penalty value using the penalty value retrieved from the first beacon frame, and update this default penalty value (by substitution or modification) based on the penalty value retrieved from each consecutive trigger frame before the next beacon frame. In this way, the AP can adjust the penalty value to be applied over time. In other words, to obtain the final penalty value to be applied to the current value to obtain the penalized value for the queue contention parameter, the node uses the penalty value contained in the trigger frame to modify the penalty value contained in the beacon frame.

[0315] In the second embodiment, the penalty value is defined by a standard rather than a fixed value transmitted from the AP. Therefore, it is retrieved from the node's local memory.

[0316] In the third embodiment, the penalty value to be applied to the EDCA / channel contention parameters can be determined based on the amount of data transmitted at step 1060. This information can be retrieved from the list updated at step 1040. The data amount can be expressed as a multiple of the reference data amount, typically 256 bytes.

[0317] In the third embodiment, the node multiplies the data volume by a penalty factor. This method allows the node to modify the current value of the channel contention parameter to the penalized value based on the amount of data transmitted in the resource unit accessed in step 1060.

[0318] The first embodiment described above can be used to retrieve the penalty factor: it can be retrieved from the TF, from the beacon frame (and possibly updated), or it can be a fixed value.

[0319] Considering the actual amount of data transmitted, it is advantageous to avoid severely penalizing nodes that only send a reduced amount of data via the OFDMA scheme.

[0320] In the fourth embodiment, the penalty value applied to the EDCA / channel parameters depends on the priority of the traffic queue, i.e., on the data type being considered (see...). Figure 2b ).

[0321] In this scenario, the node thus retrieves a set of penalty values, each associated with a specific AC queue or data type. Of course, each of these penalty values ​​can be calculated according to any of the first, second, and third embodiments described above.

[0322] Specifically, received beacon frames or received trigger frames may include multiple penalty values ​​associated with the corresponding data type. In this case, the node selects a penalty value from the multiple penalty values ​​based on the data type associated with the traffic queue corresponding to the channel contention parameter to be modified.

[0323] Once one or more penalty values ​​are retrieved, step 1080 is executed to actually modify the EDCA / channel contention parameters (one or more). As mentioned above, this is to reduce the probability of node EDCA transmission.

[0324] As is well known, the EDCA transmission probability is mainly controlled by two parameters: the first is the size of the congestion window (CW) of each AC queue 210, and the second is the current value of the AC / queue backoff 211, which decreases over time to allow nodes to access the communication channel after reaching zero. EDCA parameters also include the boundary CW. min CW maxAnd the arbitration inter-frame spacing AIFS.

[0325] Therefore, step 1080, which modifies one or more EDCA parameters by applying a penalty value, can operate on one or more of these elements.

[0326] In this embodiment, the modified channel contention parameters include queue backoff values, such as all queue backoff value 211.

[0327] In other embodiments, the modified channel contention parameters include the size of the contention window CW from which the queue backoff value 211 is initially selected.

[0328] Since the penalty value can be dynamically calculated after each MU UL transfer, it is worthwhile to modify not only the congestion window size of (one or more) AC queues but also the current queue backoff value 211.

[0329] Regarding the modification of queue backoff value 211, a node can add the retrieved penalty value (and thus use it as an offset) to such queue backoff value, preferably to each queue backoff value 211 (unless, as explained above with reference to the fourth embodiment of step 1070, a specific penalty value is used for each data type or AC priority).

[0330] In cases seeking similar changes to affect various EDCA queues, the penalty value used as the offset can be adjusted based on the corresponding congestion window size (which can be done per traffic queue, if appropriate). In other words, the penalty value added to the queue backoff value is a function of the contention window size initially chosen for the queue backoff value. In practice, the larger the contention window size, the higher the queue backoff value overall. Therefore, for fairness, it is preferable to make the impact on the traffic queue proportional to the contention window.

[0331] For example, the added penalty value (used as an offset) can be calculated as the previously retrieved penalty value (step 1070) and the lower bound of the selection range CW between the competition window size CW and the selected CW. min The penalty is the product of the ratios between them. Therefore, the penalty also takes into account an estimate of the network load to make it fair and effective.

[0332] Modifications to the contention window size CW (arbitrarily all CWs of the AC queue or a specific CW) can be made by multiplying CW by the penalty factor determined in step 1070.

[0333] Can be used for the lower bound CW min and / or upper bound CW max Similar modifications are provided, both defining the selection range from which to choose CW.

[0334] It can be noted that OFDMA access can clear one or more traffic queues 210. To ensure consistency between the EDCA backoff values ​​211 in a given situation and the contents of their associated traffic queues 210, it is also provided at step 1080 that when no data to be transmitted to the access point remains in the traffic queue after the data transmission step, the node can clear (i.e., deactivate) the queue backoff value corresponding to the traffic queue.

[0335] By providing adjustments to the (penalty) EDCA / channel contention parameters, this invention restores fairness between legacy nodes and 802.11ax nodes, assuming the latter have additional opportunities to access the medium via the RU provided by the AP.

[0336] As mentioned above, the AP can provide one or more penalty values ​​to the node. These can be added to the transmitted TFS or beacon frames.

[0337] For the purpose of explanation, see now. Figure 11a The description explains how this penalty value is calculated and provided via AP.

[0338] As described above, the AP determines a penalty value (one or more penalty values) based on the history of data received from the node (transmitted via EDCA or OFDMA); and

[0339] The node is driven to modify the current value of one or more EDCA / channel contention parameters to the penalized value based on the penalty value sent after the node transmits data through the access resource unit. This is also to reduce the probability of a node accessing the communication channel through contention, thereby restoring fairness regarding legacy nodes.

[0340] Figure 11a The flowchart illustrates the general steps an AP takes to calculate and send one or more penalty values. Of course, if the AP does not send such a penalty value, it performs normal processing.

[0341] After a node receives data arbitrarily through a communication channel accessed by one or more nodes or a resource unit accessed by one or more nodes, step 1100 is executed continuously by the AP, whereby each resource unit forms part of the transmission opportunity granted to the access point on the communication channel. Therefore, step 1100 is performed after each new data packet is received from the node.

[0342] In step 1100, the AP updates local statistics on the use of the two media access schemes (EDCA access scheme and OFDMA / RU access scheme).

[0343] Therefore, whenever the AP receives a new packet via one or the other of the two media access schemes, it updates its internal statistics on the amount of data received via each of the two schemes.

[0344] History can be based on moving time windows to effectively reflect the current state of the communication network, regardless of past events. For example, a moving time window is defined as a multiple of a beacon frame period (e.g., five beacon frame periods representing a window of approximately 500 ms). The moving time window can, for example, begin with a beacon frame. In a variation, it can be a sliding time window.

[0345] In the modification example, as described below, the history can also be made to start from the last transmission penalty value. This is particularly applicable when such transmissions are conditioned on a standard.

[0346] Still at step 1100, the relative usage ratio of the two media accesses—that is, the bandwidth usage ratio of resource units for node access (via OFDMA) to transmit data to the access point, relative to the total bandwidth usage ratio of communication channels and resource units (EDCA and OFDMA) for transmitting data to the access point via node access—can be evaluated to update the internal statistics. This ratio provides an estimate of penalized efficiency.

[0347] The AP can optionally update internal statistics about the efficiency of the two media access schemes, for example, by counting the number of collisions occurring on each media access in the basic set under consideration. These additional statistics indicate how useful the penalty process is for the current use of the network. Therefore, they can be used to determine whether to transmit a penalty value, as described below with reference to optional step 1115.

[0348] As historical statistics progress over time, the AP periodically calculates new penalty values ​​to be sent to the nodes. This is step 1110. The latter can be triggered periodically, for example, after receiving each packet from the node, or more effectively, when preparing each new beacon frame and / or each new trigger frame.

[0349] In this embodiment, the current penalty value locally on the AP is updated based on the current estimate of the bandwidth usage ratio described above. The initial penalty value when starting the AP or resetting history / statistics can be set to 0 (no penalty).

[0350] The penalty value can be defined within a range from a minimum (0 in the example above) to a maximum that may correspond to a prohibited EDCA access scheme. In embodiments, the penalty value can be discrete within the penalty range. For example, by defining the penalty range as a percentage from 0% to 100%, the penalty range can take tens of percentage points: 0%, 10%, 20%, etc. Using discrete values ​​provides system stability.

[0351] For example, whenever the assessed ratio falls below a predetermined target threshold (e.g., 20% – defined by the cell administrator or set by a standard), the current penalty value increases. This increase continues until the usage rate of the MU UL OFDMA media access scheme reaches the target threshold. Therefore, it promotes the use of MU UL OFDMA media access for 802.11ax nodes.

[0352] On the other hand, whenever the evaluation of the ratio exceeds a predetermined target threshold, the current penalty value decreases. This is to, in turn, reduce the risk of collisions in the MU uplink by promoting the RU.

[0353] Furthermore, the penalty value for deciding whether to send or not can be based on statistics regarding the efficiency of the two media access schemes. For example, the decision to send the current penalty value might depend on the ratio between the number of access resource units experiencing collisions and the total number of resource units accessed by nodes to send data to the access point.

[0354] As an example, when the ratio of conflicting resource units remains low (below a predetermined threshold), the promotion of MU UL OFDMA media access can be strengthened (by sending the penalty value or any new penalty value). On the other hand, when the ratio of conflicting resource units is too high, the promotion of MU UL OFDMA media access should be reduced (by not sending the penalty value or any new penalty value).

[0355] In the modified example, the penalty value can be a fixed value provided by the standard (and therefore stored locally on the AP), and calculated to optimize the usage rate of the MU UL media access scheme. The AP can therefore only retrieve this value from local storage.

[0356] Therefore, immediately following step 1110, the AP may optionally determine at step 1115 whether the conflict-based ratio is low or high. If it is high, the penalty value calculated at step 1110 (not shown in the figure) is not sent.

[0357] Otherwise, AP will send the penalty value to the node.

[0358] In this embodiment, a penalty value is sent in the next trigger frame, which reserves the transmission opportunity for the access point on the communication channel and defines the resource unit RU that forms the communication channel. Therefore, step 1120 is executed, in which the current value of the penalty is inserted into the next trigger frame to be sent to the node. Figure 11b As shown, this can be achieved by inserting a penalty value into the trigger dependency information field 1180 of the trigger frame.

[0359] Figure 11b This shows the structure of a trigger frame as defined in the 802.11ax draft standard.

[0360] The trigger frame 1160 consists of a dedicated field 1170 called the public information field. This field contains a "trigger dependency public information" field 1180 in which penalty values ​​can be inserted.

[0361] Other fields of the trigger frame are defined in the 802.11ax standard.

[0362] Once the penalty value is inserted into the trigger frame, it can be sent to the node at step 1130.

[0363] These embodiments are advantageous when the penalty value is dynamically calculated by the AP.

[0364] In other embodiments, a penalty value is sent in the next beacon frame before broadcasting network information about the communication node to multiple nodes. Therefore, step 1140, in which the penalty value is inserted into the next beacon frame, is performed. This can be accomplished by inserting a PP into the dedicated information element.

[0365] Next, step 1150 is executed, and a beacon frame containing the penalty value is sent to all nodes.

[0366] These other embodiments are advantageous when the penalty value is a fixed value retrieved by the AP from local memory.

[0367] Referring to the fourth embodiment of step 1070 above, the AP should calculate and send a set of penalty values ​​corresponding to each data type (or AC priority). This means that: the access point determines the penalty value for each type of data from the history of received data with the same data type (as in step 1110); and the AP sends multiple penalty values ​​associated with the corresponding data type to the node.

[0368] Although the present invention has been described above with reference to specific embodiments, the present invention is not limited to the specific embodiments, and modifications will be readily apparent to those skilled in the art that fall within the scope of the present invention.

[0369] When referring to the illustrative embodiments described above, those skilled in the art will be enlightened to many further modifications and variations, 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. In particular, different features from different embodiments may be exchanged where appropriate.

[0370] In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude multiple. The fact that different features are described in mutually different dependent claims does not indicate that combinations of these features cannot be used advantageously.

Claims

1. A communication device, comprising: The first receiving unit is configured to receive data from the first network; The transmission unit is configured to transmit data having an access class according to the data received by the first receiving unit using a resource unit that conforms to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards and is specified by another communication device, which constitutes a second network different from the first network. as well as The control unit is configured to perform control when the transmission unit transmits data and the value of a predetermined parameter transmitted from the other communication device is a predetermined value, such that communication based on Enhanced Distributed Channel Access (EDCA) is not performed within a predetermined time period.

2. The communication apparatus of claim 1, further comprising a second receiving unit configured to receive a trigger frame including information about the resource unit from the other communication apparatus.

3. The communication device according to claim 2, wherein the trigger frame includes the value of the predetermined parameter.

4. The communication device according to claim 2, wherein the trigger frame is a frame conforming to the IEEE 802.11 series of standards.

5. The communication apparatus of claim 1 further includes a third receiving unit configured to periodically receive beacon frames from the other communication apparatus, the beacon frames including network information about the second network and the value of the predetermined parameter.

6. The communication apparatus of claim 1, wherein the predetermined parameter comprises a plurality of values ​​respectively associated with a plurality of access categories.

7. The communication apparatus of claim 6, wherein the control unit controls EDCA-based communication for the access class of the data transmitted by the transmission unit based on one of the plurality of values.

8. The communication apparatus of claim 1, wherein the control unit performs control when the value of the predetermined parameter is not the predetermined value, such that ECDA-based communication is performed based on the value of the predetermined parameter during the predetermined time period.

9. The communication apparatus of claim 1, wherein the control unit performs control such that EDCA-based communication is performed based on the value of the predetermined parameter by updating the value of the channel contention parameter associated with the EDCA-based communication.

10. The communication apparatus of claim 9, wherein the value of the channel contention parameter includes a backoff value.

11. The communication apparatus of claim 10, further comprising a decrementing unit configured to decrement the backoff value until the backoff value reaches zero.

12. The communication apparatus of claim 10, wherein the control unit updates the contention window associated with EDCA-based communication based on the value of the predetermined parameter, and selects the backoff value based on the updated contention window.

13. The communication device of claim 12, wherein the predetermined parameter includes information about the maximum and minimum values ​​of the contention window.

14. The communication apparatus of claim 1, wherein the control unit performs control such that EDCA-based communication is performed based on the value of the predetermined parameter by updating the value of the arbitration inter-frame spacing (AIFS) associated with the EDCA-based communication based on the value of the predetermined parameter.

15. The communication apparatus of claim 1, wherein the designated resource unit is a random resource unit determined for transmitting data using parameters for accessing the resource unit.

16. The communication apparatus of claim 1, wherein in response to successfully transmitting data using the resource unit, the control unit performs control such that EDCA-based communication is not performed during the predetermined time period when the value of the predetermined parameter is the predetermined value, and the control unit performs control such that EDCA-based communication is performed during the predetermined time period when the value of the predetermined parameter is not the predetermined value.

17. The communication apparatus of claim 16, wherein successful data transmission using the resource unit is achieved when an acknowledgment response to the data is received from the other communication apparatus.

18. The communication apparatus of claim 1, wherein transmitting data using the resource unit is transmitting data via a multi-user uplink using orthogonal frequency division multiple access.

19. The communication device of claim 1, wherein the control unit performs control such that EDCA-based communication is performed by reducing the probability of the communication device accessing the communication channel of the second network based on the value of the predetermined parameter.

20. The communication device of claim 1, wherein the other communication device is an access point conforming to the IEEE 802.11 series of standards.

21. A communication method, comprising: Receive data from the first network; Data with access class based on the received data is transmitted using resource units conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards and designated by another communication device, which constitutes a second network different from the first network; as well as Control is performed when data is transmitted and the value of a predetermined parameter transmitted from the other communication device is a predetermined value, such that communication based on Enhanced Distributed Channel Access (EDCA) is not performed within a predetermined time period.

22. A computer-readable recording medium storing a program for causing a computer to perform steps performed by a communication device according to any one of claims 1-20.

23. A communication method in a communication network comprising multiple nodes, the method comprising, at nodes included in the plurality of nodes and configured to constitute the communication network: In a beacon frame conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards, predetermined parameters are transmitted to at least one other node among the plurality of nodes, wherein the values ​​of the predetermined parameters are predetermined values ​​and include multiple values ​​respectively associated with multiple data types. in, If data is successfully transmitted using the resource unit specified in the trigger frame transmitted from the node, the at least one other node performs control based on the value of the predetermined parameter transmitted from the node being the predetermined value, to prevent communication based on Enhanced Distributed Channel Access (EDCA) from being performed for a predetermined time period.

24. The communication method of claim 23, wherein the beacon frames are periodically transmitted from the node.

25. The communication method of claim 23, wherein the control performed by the at least one other node based on the value of the predetermined parameter transmitted from the node being the predetermined value includes control for not performing EDCA-based communication of a predetermined data type based on one of the plurality of values.

26. The communication method of claim 23, wherein the control performed by the at least one other node based on the value of the predetermined parameter transmitted from the node being the predetermined value is performed by updating the value of a channel contention parameter associated with the EDCA-based communication.

27. The communication method of claim 26, wherein the value of the channel contention parameter includes a backoff value, and the backoff value decreases over time by the at least one other node until the backoff value reaches zero.

28. The communication method of claim 23, wherein successfully transmitting data using the resource unit occurs when the node receives an acknowledgment response for the data.

29. The communication method according to claim 23, wherein transmitting data using the resource unit is transmitting data via a multi-user uplink using orthogonal frequency division multiple access.

30. The communication method of claim 23, wherein the node is an access point conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards.

31. A communication device configured to operate as a node in a communication network comprising a plurality of nodes, the nodes being included among the plurality of nodes and constituting the communication network, the device comprising: The transmission unit is configured to transmit predetermined parameters to at least one other node among the plurality of nodes in a beacon frame conforming to the Institute of Electrical and Electronics Engineers (IEEE) 802.11 series of standards, wherein the values ​​of the predetermined parameters are predetermined values ​​and include multiple values ​​respectively associated with multiple data types. In the event that data is successfully transmitted using the resource unit specified in the trigger frame transmitted from the node, the at least one other node performs control based on the value of the predetermined parameter transmitted from the node being the predetermined value, so as not to perform communication based on Enhanced Distributed Channel Access (EDCA) for a predetermined time period.

32. A computer-readable recording medium storing a program for causing a computer to perform the communication method according to any one of claims 23 to 30.

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