Non-zero random backoff procedure

Abstract

A wireless local area network (WLAN) protocol with a non-zero backoff procedure, defined by setting a backoff counter to a random value greater than or equal to at least one backoff slot when beginning to contend for the channel. This is preferably used in combination with setting an arbitration interframe space (AIFS) time to an amount less than the time used for traditional backoff. The parameters controlling the non-zero backoff can be set by the contending station, or set by the associated access point (AP), or set in response to negotiation between the station and the AP. In some cases, the station can switch between enabling and disabling the non-zero backoff procedure during different time periods.

Description

[0001] Cross Reference to Related Applications

[0002] This application claims priority to and the benefit of U.S. Patent Application Serial No. 17 / 509,015, filed October 24, 2021, which is incorporated by reference herein in its entirety. This application also claims priority to and the benefit of U.S. Provisional Patent Application Serial No. 63 / 168,449, filed March 31, 2021, which is incorporated by reference herein in its entirety.

[0003] Statement as to Federally Sponsored Research and Development

[0004] Not Applicable

[0005] Statement as to Copyright

[0006] A portion of the material in this patent document can be subject to copyright protection under the copyright laws of the United States and of other countries. The owner of the copyright rights has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office publicly available files and records, but otherwise reserves all copyright rights whatsoever. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office expressly for the limited purposes of search, study or use in relation to the United States Patent and Trademark Office, facsimile, electronic, mechanical or other reproduction by or for the United States Patent and Trademark Office, customers of the Patent and Trademark Office, and users of the Patent and Trademark Office Libraries or Records. TECHNICAL FIELD

[0007] The technology of the present disclosure relates generally to channel contention procedures on wireless networks using CSMA / CA procedures, and more particularly to channel contention procedures that provide a bounded contention time when accessing a channel. BACKGROUND

[0008] Current wireless technologies using CSMA / CA focus on high throughput performance of the network, but fall short in supporting low latency applications, such as real-time applications (RTAs), that require low latency and use best effort communications. Data generated from RTAs is referred to herein as RTA traffic and is packaged as RTA packets at the sender STA; while data generated from non-time sensitive applications is referred to herein as non-RTA traffic and is packaged as non-RTA packets at the sender STA. Due to the high timeliness requirement of its packet delivery, RTA packets require low latency, where RTA packet data is only valid for a certain period of time.

[0009] However, with respect to prioritizing RTS packet traffic, there is often an unnecessary trade-off in existing systems.

[0010] Thus, there is a need for improved mechanisms for channel contention that are better suited for real-time applications without causing a significant impact on the throughput of regular traffic. SUMMARY

[0011] In current (legacy) wireless communication systems, the random backoff procedure can result in accessing the channel without decrementing any backoff slots, which results in an unbounded contention time (the time of one backoff procedure), and thus is not suitable for transmissions that require a bounded latency.

[0012] A non-zero backoff procedure is described for ensuring that during the backoff procedure, the backoff counter must be decremented at least once between two CCA busy events. Thus, the contention time of an AC can be bounded by (CWmax+1)*TXOP_limit, where CWmax is the maximum contention window size of the AC and TXOP_limit is the maximum TXOP limit of all ACs. The non-zero backoff procedure is preferably used in combination with setting a short arbitration interframe space (AIFS) time (also referred to as AIFS number (AIFSN)) for the AC to give the non-zero backoff procedure of the AC a higher priority compared to the legacy backoff procedure of the same AC.

[0013] In the following parts of the specification, other aspects of the technology described herein will be presented, where detailed descriptions are used to fully disclose preferred embodiments of the technology, without imposing limitations thereto. BRIEF DESCRIPTION OF DRAWINGS

[0014] The technology described herein will be more fully understood from the following detailed description, taken in conjunction with the accompanying drawings, in which:

[0015] FIG. 1 is a flow diagram of a WLAN system using carrier sense multiple access / collision avoidance (CSMA / CA) in accordance with IEEE 802.11.

[0016] FIG. 2 is a data field diagram of a data frame defined in IEEE 802.11.

[0017] FIG. 3 is a data field diagram of an ACK frame format defined in IEEE 802.11.

[0018] FIG. 4 is a data field diagram of a HE single user (SU) PPDU format defined in IEEE 802.11.

[0019] FIG. 5 is a communication diagram of a retransmission in CSMA / CA in IEEE 802.11 with increased backoff time due to retransmission.

[0020] FIG. 6 is a communication diagram of discarding a packet after the number of retransmissions exceeds a retry limit in IEEE 802.11.

[0021] FIG. 7 is a queue diagram showing EDCA queues of ACs and EDCA functions defined in IEEE 802.11.

[0022] Figure 8 is a communication diagram of the channel access procedure of EDCA defined in IEEE 802.11.

[0023] Figure 9 is a data field diagram of the format of the EDCA Parameter Set element defined in IEEE 802.11.

[0024] Figure 10 is a data field diagram of the QoS Info field when the AP transmits in IEEE 802.11.

[0025] Figure 11 is a data field diagram of the format of the AC Parameter Record field defined in IEEE 802.11.

[0026] Figure 12 is a hardware block diagram of a wireless station hardware in accordance with at least one embodiment of the disclosure.

[0027] Figure 13 is a hardware block diagram of a multi-link device in accordance with at least one embodiment of the disclosure.

[0028] Figure 14 is a topology of a network scenario used by way of example, and not limitation, in accordance with at least one embodiment of the disclosure.

[0029] Figure 15 is a flowchart of a non-zero backoff procedure in accordance with at least one embodiment of the disclosure.

[0030] Figure 16 is a communication diagram of a STA using a non-zero backoff procedure for channel contention in accordance with at least one embodiment of the disclosure.

[0031] Figure 17 is a communication diagram of a STA enabling and disabling a non-zero backoff procedure for channel contention during different time periods in accordance with at least one embodiment of the disclosure.

[0032] Figure 18 is a flowchart of an AP transmitting an EDCA Parameter Set element to its associated STAs in accordance with at least one embodiment of the disclosure.

[0033] Figure 19 is a queue diagram of EDCA queues in accordance with at least one embodiment of the disclosure, where a STA uses some EDCA Fs for a non-zero backoff procedure and other EDCA Fs for a legacy backoff procedure.

[0034] Figure 20 is a flowchart of using a new EDCA Parameter Set element to set parameters of a non-zero backoff procedure in accordance with at least one embodiment of the disclosure.

[0035] Figure 21is a diagram of a data field of a frame including EDCA parameter settings for a non-zero backoff procedure and a traditional backoff procedure, respectively, according to at least one example of the present disclosure.

[0036] Figure 22 is a diagram of data fields for a non-zero backoff EDCA parameter set according to at least one example of the present disclosure.

[0037] Figure 23 is a queue diagram of an EDCA system showing AC and EDCA-enabled STAs using EDCAF for a non-zero backoff procedure and other EDCAFs for a traditional backoff procedure in accordance with at least one example of the present disclosure.

[0038] Figure 24 A communication diagram is provided in which a STA uses a shorter arbitration interframe space (AIFS) time than a conventional STA for the same AC using a non-zero backoff procedure according to at least one example of the present disclosure.

[0039] Figure 25 is a communication diagram illustrating another example of a STA using a shorter AIFS time than a legacy STA for a non-zero backoff procedure for the same AC according to at least one example of the present disclosure. DETAILED DESCRIPTION

[0040] 1. Introduction

[0041] RTA packets require low latency due to their high timeliness requirements for packet delivery. RTA packets are efficient when delivered within a certain period of time. Some RTA packet flows also benefit from (or require) the bounded (more predictable) channel contention time provided by CSMA / CA wireless systems.

[0042] In the random channel access scenario of CSMA / CA, each STA needs to sense and contend for channel access before sending each packet. Although short channel contention time speeds up channel access, it does not provide a bounded channel access time. The delay caused by channel contention is still significant and unpredictable.

[0043] This paper describes a process for bounding the delay caused by channel contention by utilizing a non-zero (NZ) backoff procedure that can be beneficial for RTA packets. The disclosed non-zero backoff procedure ensures a bounded time for STAs to complete channel contention. Furthermore, the non-zero backoff procedure achieves a higher probability of earlier channel access than the traditional backoff procedure, assuming the same EDCA parameters, except that the arbitration interframe space (AIFS) of the non-zero backoff procedure is shorter than that of the traditional backoff procedure.

[0044] 2. WLAN 802.11 system

[0045] 2.1 CMSA / CA system

[0046] Figure 1 depicts a WLAN system that uses carrier sense multiple access / collision avoidance (CSMA / CA) to allow stations (STAs) to gain channel access for packet transmission and retransmission according to IEEE 802.11.

[0047] In the CSMA / CA system, before each transmission and retransmission, a STA must sense the channel and set a backoff time to contend for channel access. The backoff time is determined by a uniform random variable between 0 and the size of a contention window (CW). After the STA waits for the backoff time and senses that the channel is idle, the STA proceeds to transmit (send) the packet.

[0048] If the STA does not receive an ACK before the timeout, a retransmission can be needed; otherwise the transmission is successful. When a retransmission is needed, the STA checks the number of retransmissions of the packet. If the number of retransmissions exceeds a retry limit, the packet is discarded and no retransmission is scheduled. Otherwise, a retransmission is scheduled.

[0049] If a retransmission is scheduled, another backoff time is needed to contend for retransmission channel access. If the size of the contention window does not reach an upper limit, the STA increases the size of the contention window.

[0050] The STA sets another backoff time depending on the new size of the contention window. The STA waits for the backoff time for retransmission and continues in this way.

[0051] Figure 2 illustrates a data frame format in a conventional WLAN system. The frame control field indicates the type of the frame. The duration field contains NAV information for CSMA / CA channel access. The RA field contains the address of the recipient of the frame. The TA field contains the address of the STA that sends the frame. The sequence control field contains the fragment number and sequence number of the packet. The HT control field indicates additional control information of the frame.

[0052] Figure 3 illustrates an ACK frame format in a conventional WLAN system. The frame control field indicates the type of the frame. The duration field contains NAV information for CSMA / CA channel access. The RA field contains the address of the recipient of the frame.

[0053] Figure 4 illustrates an HE single user (SU) PPDU format for single user transmission in IEEE 802.1 lax, which contains the following fields.

[0054] The L-STF field provides a non-HT short training field. The L-LTF field provides a non-HT long training field. The L-SIG field provides a non-HT signal field. The RL-SIG field provides a repeated non-HT signal field. The HE-SIG-A field provides an HE signal A field. The HE-STF field provides an HE short training field. The HE-LTF field provides an HE long training field. The Data field is the field carrying the PHY layer convergence protocol service data unit (PSDU). The PE field is the packet extension field.

[0055] Figure 5 illustrates one example of retransmission in CSMA / CA with increased backoff time in response to retransmission. The data frame and ACK frame use the formats shown in Figures 2 and 3, respectively. The frames are packed using the packet format shown in Figure 4. In this example, after the initial transmission of the packet by the sender, it does not receive an ACK before the ACK timeout. Then, to retransmit, it sets another backoff time, where the size of the contention window is n slots. After waiting for this backoff time, the sender STA retransmits the packet for the first time. However, the retransmission also fails. The sender STA needs to retransmit the packet and sets another backoff time to contend for channel access. This time, due to the retransmission, the size of the contention window is doubled, to 2*n slots. The expected backoff time is also doubled due to the contention window size. The second retransmission succeeds, as it receives an ACK before the timeout.

[0056] Figure 6 illustrates one example of discarding a packet after the number of retransmissions exceeds the retry limit. In this example, the retry limit is denoted by "R". The data frame and ACK frame use the formats shown in Figures 2 and 3, respectively. The frames are packed using the packet format shown in Figure 4. As shown in Figure 6, after the initial transmission of the packet fails, the sender STA retransmits the packet multiple times. However, none of the retransmissions succeed. After retransmitting R times, the number of retransmissions exceeds the retry limit, the sender STA stops retransmitting the packet, and the packet is discarded.

[0057] 2.2. EDCA queues in 802.11

[0058] Figure 7 illustrates a reference model of enhanced DCF channel access (EDCA) queues in IEEE 802.11; where DCF stands for distributed coordination function. The system contains six transmit queues and four access categories (ACs). Each AC uses an EDCA function (EDCAF) to contend for channel access to transmit packets from its corresponding transmit queue, which is an enhanced variant of DCF.

[0059] The six transmit queues are voice (VO), alternate voice (A_VO), alternate video (A_VI), video (VI), best effort (BE), and background (BK). Each transmit queue determines the order of transmission of packets in the queue.

[0060] The four ACs are voice (VO), video (VI), best effort (BE), and background (BK). Each AC has an EDCA function (EDCAF) to provide the function of channel contention. When multiple EDCAFs attempt to access the channel at the same time, an internal collision avoidance mechanism is used. When an internal collision occurs, the higher priority EDCAF will gain channel access.

[0061] Table 1 lists the user priority (UP) to access category (AC) mapping used in the EDCA queues of IEEE 802.11. The second and third columns indicate the user priority of the traffic and its corresponding designation in IEEE 802.1D. In each row, the traffic will be queued in the corresponding transmit queue and access category in order of user priority. The priority increases from top row to bottom row. The higher priority traffic has a higher probability of being transmitted earlier.

[0062] Figure 8 illustrates the channel access procedure of EDCA. As shown in the figure, it also compares the EDCA channel access with the distributed coordination function (DCF).

[0063] DCF is the basic medium access protocol of IEEE 802.11, which employs CSMA / CA with an exponential backoff algorithm. For DCF, when a STA determines that the medium is idle at the arrival of a frame to be transmitted, the STA can immediately access the channel, and the medium is idle for the DCF interframe space (DIFS) time. Otherwise, it follows a backoff procedure to contend for the channel. After sensing the channel to be idle for the DIFS time, it starts counting down the backoff as long as the medium is idle. The number of backoff slots is randomly selected between 0 and its contention window. When CCA busy (or medium busy) occurs, i.e., when the STA senses the channel to be busy, the STA suspends counting down the backoff. When the backoff counts down to 0, the STA starts transmitting the packet.

[0064] It should be appreciated that DCF is a CSMA / CA with an exponential backoff algorithm, and EDCA is implemented based on DCF. In the reference of current IEEE 802.11 amendment 11REVmd D5.0, it states: "The basic access method used by the MAC of non-DMG STAs is DCF, which is called Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA). DCF shall be implemented in all STAs. The EDCA channel access protocol is derived from the DCF procedure described in 10.3 (DCF) by the use of four different access categories (ACs), which add four independent enhanced distributed channel access functions (EDCAs) to provide different priorities for the traffic to be transmitted."

[0065] In EDCA, the EDCAF of an AC as shown in FIG. 7 can immediately access the channel, and the medium is idle for an arbitration inter-frame space (AIFS) time (or number) of the AC when the EDCAF determines that the medium is idle at the arrival of an empty queue of frames to the AC for transmission. It should be noted that AIFS[i] shown in the figure represents the AIFS time of AC i; where "i" represents any one of the ACs. Otherwise, each EDCAF follows a backoff procedure to contend for the channel and gain channel access for the AC. After sensing the channel idle for the AIFS time, it starts counting down the backoff as long as the medium is idle. The number of backoff slots is randomly selected between 0 and the contention window size of the AC. When an idle channel assessment (CCA) busy (or medium busy) occurs, i.e., when the channel is sensed busy, the EDCAF suspends counting down the backoff. When the backoff of the EDCAF counts down to 0, the STA starts transmitting a packet for the AC.

[0066] It should be appreciated that multiple EDCAFs can contend for the channel in parallel. For example, as shown in FIG. 8, the EDCAFs for AC i and AC j (both i and j represent any AC) can contend for the channel at the same time. When an internal collision occurs, the EDCAF with higher priority gains channel access, and the EDCAF with lower priority doubles its contention window. An AC can reserve a contention-free time, e.g., a TX opportunity (TXOP) for transmitting packets. The maximum duration of TXOP is denoted as TXOP limit.

[0067] Table 2 lists the default parameter settings of EDCA channel access. Each AC has its own minimum contention window and maximum contention window. The AIFS number (AIFSN) represents the AIFS duration with the number of backoff slots, and is also referred to as AIFS time in this document. The TXOP limit represents the maximum duration of TXOP that each AC can reserve each time, except when the TXOP limit is set to zero. When the TXOP limit is set to zero, the STA cannot reserve TXOP for multiple packet transmissions.

[0068] 2.3. EDCA Parameter Set element

[0069] The AP can send or broadcast a frame including the EDCA Parameter Set element to set the EDCA parameters on its associated STAs.

[0070] Figure 9 illustrates the format of the EDCA Parameter Set element defined in IEEE 802.11. The element ID field contains the identification of the element, which in this case indicates that the element is an EDCA Parameter Set element. The length field indicates the length of the element. The QoS Info field is defined in IEEE 802.11 as shown in Figure 10. The Updated EDCA Info field is defined in IEEE 802.11 and is reserved for non-SI G STAs. The AC_BE Parameter Record field carries the EDCA parameters for AC_BE. The format of this subfield and the subsequent subfields are shown in Figure 11. The AC_BK Parameter Record field carries the EDCA parameters for AC_BK. The AC_VI Parameter Record field carries the EDCA parameters for AC_VI. The AC_VO Parameter Record field carries the EDCA parameters for AC_VO.

[0071] Figure 10 illustrates the format of the QoS Info field defined in IEEE 802.11 when sent by an AP. The EDCA Parameter Set Update Count field indicates the version of the EDCA Parameter Set. If a non-AP STA receives an EDCA Parameter Set Update Count field with a value different from the value it stores, the STA shall update the EDCA parameters according to the most recently received EDCA Parameter element. The Q-ACK field is set to the first state (e.g., "1") when dot11QAckOptionImplemented is true, otherwise it is set to 0. The Queue Request field is set to the first state (e.g., "1") if the AP can handle non-zero Queue Size subfields in the QoS Control field of QoS Data frames, otherwise it is set to the second state (e.g., "0"). The TXOP Request field is set to the first state (e.g., "1") if the AP can handle non-zero TXOP Duration Request subfields in the QoS Control field of QoS Data frames, otherwise it is set to the second state (e.g., "0").

[0072] Figure 11 illustrates the format of the AC_X (e.g., AC_VO, AC_VI, AC_BE, AC_BK) Parameter Record field defined in IEEE 802.11. The AC / AIFSN field indicates the parameter set of the access category (AC) and AIFSN for this field. The ECWmin / ECWmax field indicates the minimum contention window (CW) size and the maximum CW size for the AC. The TXOP Limit field indicates the TXOP limit for the AC.

[0073] 3. Problem Statement

[0074] Prior to the present disclosure, wireless communication systems using 802.11, utilizing a random backoff process, could access the channel without decrementing any backoff slots. Consequently, it is possible that during a STA's backoff process, the STA's backoff counter may not decrease between two consecutive CCA busy events if the second CCA busy event is caused by another STA accessing the channel without decrementing any backoff slots. Consequently, the contention time (the duration of one backoff process) is unbounded (unconstrained). This type of operation is unsuitable for transmissions requiring bounded latency.

[0075] 4. Contributions of this Disclosure

[0076] The disclosed technology describes a non-zero (NZ) backoff procedure to ensure that the backoff counter is set (initialized) to at least one count. For example, the backoff counter is set to a random number between 1 and CW+1. It should be noted that the traditional backoff procedure can initialize its backoff counter to 0 because the backoff counter is randomly selected between 0 and CW. If all STAs use the non-zero backoff procedure, the STA's backoff counter must be decremented by at least one count between two CCA busy events. In this case, when the non-zero backoff procedure is used, the time it takes to count down the STA's backoff counter to zero is bounded by (CWmax+1)*TXOP_limit, where CWmax is the maximum contention window size of the backoff procedure and TXOP_limit is the maximum contention-free channel time that a STA can reserve for transmission after gaining channel access. When the EDCAF of an AC in EDCA uses this non-zero backoff procedure, it is preferably used with a shorter AIFS time (smaller AIFSN) so that the non-zero backoff procedure is given higher priority than the traditional backoff procedure with the same CW.

[0077] 5. Examples

[0078] 5.1.STA and MLD Hardware Configuration

[0079] Figure 12Figure illustrates an example embodiment 10 of a wireless station (STA) configured to perform the protocol of the present disclosure. An external I / O connection 14 is preferably coupled to an internal bus 16, on which are connected a CPU 18 and memory (e.g., RAM) 20 for executing programs implementing the communication protocol. The host accommodates at least one modem 22 to support communications, which is coupled to at least one RF module 24, 28, each of which is connected to one or more antennas 29, 26a, 26b, 26c ~ 26n. An RF module with multiple antennas (e.g., an antenna array) allows for beamforming during transmission and reception. As such, the STA can use multiple sets of beam patterns to transmit signals.

[0080] The bus 14 allows various devices to be connected to the CPU, e.g., to sensors, actuators, etc. Instructions from the memory 20 are executed on the processor 18 to perform programs implementing the communication protocol, the execution of which allows the STA to play different roles on the network, such as the role of an access point (AP) station or a regular station (non-AP STA). It should also be appreciated that the programming is configured to operate in different modes (TXOP holder, TXOP shared participant, source, intermediary, destination, first AP, other AP, station associated with the first AP, station associated with the other AP, coordinator, coordinated, etc.) depending on the role it plays in the current communication context.

[0081] The STA hardware is thus shown configured with at least one modem and associated RF circuitry for providing communications on at least one frequency band. This can be any desired combination of sub-6 GHz bands and directional bands. At least one embodiment of the present disclosure is configured to use sub-6 GHz bands.

[0082] It should be appreciated that the present disclosure can be configured with multiple modems 22, each coupled to any number of RF circuitry. In general, using a larger number of RF circuitry will result in a wider coverage of the antenna beam direction. It should be appreciated that the number of RF circuitry used and the number of antennas are determined by the hardware constraints of the particular device. When the STA determines that it does not need to communicate with neighboring STAs, a portion of the RF circuitry and antennas can be disabled. In at least one embodiment, the RF circuitry includes frequency converters, array antenna controllers, etc., and is connected to multiple antennas that are controlled for beamforming for transmission and reception. As such, the STA can use multiple sets of beam patterns to transmit signals, each beam pattern direction being considered as an antenna sector.

[0083] Also, note that multiple instances of station hardware as shown in the figures can be combined in various ways into a multi-link device (MLD), which will generally have a processor and memory for coordinating activities, though each STA within the MLD does not always need a separate CPU and memory.

[0084] Figure 13 An example embodiment 40 illustrating a multi-link device (MLD) hardware configuration is shown. Multiple STAs belong to the MLD, each operating on a link of a different frequency. The MLD has access to external I / O 41 for applications, which connects to an MLD management entity 48 having a CPU 62 and memory (e.g., RAM) 64 to allow execution of programs implementing communication protocols at the MLD level. The MLD can assign tasks to and collect information from the various belonging stations (here exemplified as STAl 42, STA2 44,..., STAN 46) to which it is connected, and share information among the belonging STAs.

[0085] In at least one embodiment, each STA of the MLD has its own CPU 50 and memory (RAM) 52, typically coupled through a bus 58 to at least one modem 54, which connects to at least one RF circuit 56 having one or more antennas. In this example, the RF circuit has multiple antennas 60a, 60b, 60c,..., 60n, such as in an antenna array. The modem, in combination with the RF circuit and associated antennas, transmits / receives data frames to / from neighboring STAs. In at least one implementation, the RF module includes a frequency converter, an array antenna controller, and other circuitry for interfacing with its antennas.

[0086] It should be appreciated that each STA of the MLD does not necessarily need its own processor and memory, as the STAs can share resources with each other and / or with the MLD management entity, depending on the specific MLD implementation. It should be appreciated that the above MLD diagram is given by way of example and not limitation, and that the present disclosure can operate with a wide variety of MLD implementations.

[0087] 5.2. Considered STA topologies

[0088] Figure 14 An example embodiment 70 illustrating a topology (network scenario) given by way of example and not limitation is shown. This topology is provided only to explain the goal of the proposed technology, and not to limit it to a specific STA configuration.

[0089] If an AP belongs to an MLD, the MLD is considered an AP MLD. If a non-AP STA belongs to an MLD, the MLD is considered a non-AP MLD.

[0090] Figure 14 An example topology assumption is that there are 6 STAs that make up 3 MLDs in a given area (e.g., a conference room). AP1 80 and AP2 82 belong to Multi-Link Device (MLD) #1 72, STA1 84 and STA4 86 belong to MLD #2 74, and STA3 88 and STA5 90 belong to MLD #3 76. STA2 78 can exemplify a non-AP STA or a single-link MLD (i.e., a special MLD that has only one STA and operates on one link) operating on Link 1 92. STA1, STA2, and STA3 are associated with AP1 through links 1 92, 94a, and 96a; while STA4 and STA5 are associated with AP2 through links 2 94b and 96b. In these examples, all STAs use EDCA for random channel access on all links.

[0091] 5.3. Non-zero backoff procedure

[0092] A non-zero backoff procedure is a backoff procedure in which a STA must generate a random backoff (backoff slots) with a count greater than or equal to 1 to initialize a backoff counter for channel contention. The STA can then count down the backoff counter as it does in CSMA / CA. The CW can also be updated as in CSMA / CA.

[0093] When DCF or EDCA uses a non-zero backoff procedure, the STA can not be able to use immediate access of DCF or DCA, as shown in Figure 8.

[0094] The current backoff procedure used in CSMA / CA (such as DCF and EDCA) is denoted as a legacy backoff procedure because it does not support the non-zero backoff procedure described.

[0095] 5.3.1. Flowchart of an example protocol procedure

[0096] Figure 15 An example embodiment 110 of a non-zero backoff procedure is illustrated. When a STA intends to initiate 112 the transmission of one or more frames, it waits 114 until the medium / channel is idle for a period of time equal to IFS (such as DIFS, AIFS [AC_i] (AIFS when the STA contends for the channel as AC_i), EIFS defined in IEEE 802.11) without interruption. The STA can apply these different types of IFS according to the rules defined in IEEE 802.11. The STA can also use only DIFS or AIFS [AC_i].

[0097] After the IFS channel / medium is idle, the STA generates 116 a non-zero random backoff count (i.e., number of backoff slots) for an additional backoff time before transmitting. That is, the backoff count is greater than or equal to 1. The following are given as examples of different backoff count generation methods.

[0098] Backoff count = Random(), where Random() = a pseudo-random integer drawn from a uniform distribution over the interval [1, CW+1], where CW is the contention window size.

[0099] Backoff count = Random(), where Random() = a pseudo-random integer drawn from a uniform distribution over the interval [1, CW], where CW is the contention window size.

[0100] Backoff count = Random(), where Random() = a pseudo-random integer drawn from a uniform distribution over the interval [m, n], where m and n are integers, and n is greater than m, and m is greater than or equal to 1.

[0101] Then, after setting the backoff count, the STA counts down 118 the backoff counter. A check 120 determines whether the medium / channel becomes busy before the backoff counter reaches a terminal count (e.g., 0). If the medium / channel becomes busy, at block 122 it stops counting down the backoff counter and returns to block 114, where the STA waits until the medium / channel is idle without interruption for a period of time equal to IFS; then the STA continues counting down the backoff counter. Note that since the backoff counter contains a non-zero value, the STA does not generate a new random backoff count after waiting for the IFS time.

[0102] If at block 120 it is determined that the channel is not busy, then at block 124 the STA gains channel access and begins transmitting when the backoff counter equals zero.

[0103] 5.3.2 Example Backoff

[0104] Figure 16 An example embodiment 130 illustrating a STA using a non-zero backoff procedure for channel contention in DCF is shown. The network topology is shown in Figure 14 where the interaction between AP1 132, STA1 134, and STA2 136 is shown.

[0105] In this example, STA1 and AP1 are conducting a conventional backoff as defined in DCF of IEEE 802.11 138. STA2 starts a non-zero backoff procedure 140. It first waits for a DIFS time 141 and sets the backoff counter to 1 143. When the backoff counter counts down to 0 142, STA2 gains channel access and begins packet transmission 144.

[0106] It should be noted that the DIFS time shown in the figure should be replaced with the AIFS time of the AC when STA2 contends for the channel as an EDCA AC.

[0107] Figure 17 An example embodiment 150 illustrating a STA enabling and disabling the non-zero backoff procedure by time to contend for the channel is shown. The network topology is shown in Figure 14 In this example, STA1 134 and AP1 132 are depicted. STA1 uses the non-zero backoff procedure 134 during a scheduled time period 152. The scheduled time period can be determined by the STA, negotiated between the AP and the STA, or assigned by the AP. For example, the scheduled time period can be a restricted target wake-up time (TWT) service period (SP) in IEEE 802.11be or a scheduled period of HCF-controlled channel access (HCCA). Outside of the scheduled time period, STA1 disables 154 the non-zero backoff procedure and uses the legacy backoff procedure as described in the previous section to contend for the channel.

[0108] It should be noted that when STA1 uses the non-zero backoff procedure in the EDCA F, it can also use an AIFS whose time is different from that of the legacy backoff procedure. For example, for AC_VO, when STA1 uses the non-zero backoff procedure, it can set the AIFSN of AC_VO to 1. When STA1 uses the legacy backoff procedure, it can set the AIFSN of AC_VO to 2.

[0109] 5.4. Coexistence of non-zero backoff and legacy backoff

[0110] This section considers the scenario when a STA that supports the non-zero backoff procedure and a STA that does not support the non-zero backoff procedure coexist.

[0111] The current backoff procedure used in IEEE 802.11 is denoted as the legacy backoff procedure. The STA that does not support the non-zero backoff procedure is denoted as the legacy STA.

[0112] One purpose of the disclosed technology is to have the non-zero backoff procedure provide a higher priority than the legacy backoff procedure. To achieve this purpose, for the same AC, the non-zero backoff procedure can use a shorter AIFS time than the legacy backoff procedure. For example, for AC_VO, a STA that uses the non-zero backoff procedure for AC VO can set the AIFSN of AC_VO to 1, while another STA that uses the legacy backoff procedure for AC VO can set the AIFSN of AC_VO to 2. In at least one embodiment, a STA only reduces the AIFS time of an AC without using the non-zero backoff procedure to increase its priority.

[0113] It should be noted that the AIFS time should be greater than or equal to the point coordination function interframe space (PIFS) time to ensure that the error recovery procedure for retransmissions can access the channel more quickly. For example, if the AIFSN for AC_VO is set to 1 when using a non-zero backoff procedure, the AIFS time for AC_VO when using a non-zero backoff procedure is equal to the PIFS time. Since the number of backoff slots is not zero, the AIFS time plus at least one backoff slot time will always be greater than the PIFS time. That is, the recovery procedure for retransmissions can access the channel more quickly than the non-zero backoff procedure.

[0114] 5.4.1. EDCA Parameter Set for Non-Zero Backoff

[0115] Two examples of the disclosed technology are provided for setting the EDCA parameters for a non-zero backoff procedure.

[0116] 5.4.1.1. Reusing the EDCA Parameter Set Element for Non-Zero Backoff

[0117] In an IEEE 802.11 network, an AP can send a frame including an EDCA Parameter Set element as shown in Figure 9 to set the EDCA parameters for a legacy backoff procedure on its associated STAs. In at least one variant, this element can be reused to set the EDCA parameters for a non-zero backoff procedure.

[0118] Figure 18 An example embodiment 170 is illustrated in which an AP sends an EDCA Parameter Set element to its associated STAs. The purpose of the example here is for the AP to send the same EDCA parameter settings that can be used for EDCA parameter settings for both a non-zero backoff procedure and a legacy backoff procedure on its associated STAs.

[0119] The AP first sends or broadcasts 172 a frame including EDCA parameter settings (e.g., an EDCA Parameter Set element) to its associated STAs. A check 174 is made to determine if the receiver STAs support a non-zero backoff procedure. If a non-zero backoff is supported, then at block 176, the STA sets its EDCA parameter AIFSN[AC_i] (i.e., the AIFSN for AC_i) to be equal to the parameter from the AP minus 1 or more and can use a non-zero random backoff procedure to contend for the channel. For example, in the EDCA Parameter Set element from the AP, AIFSN[AC_VO] is 2. Then, for a non-zero backoff procedure for AC_VO, the STA sets AIFSN[AC_VO] to be 1. The rest of the parameters for this AC_i can be set to be the same as the parameters from the AP or adjusted similarly to the AIFSN.

[0120] Otherwise, if the receiver STA does not support the non-zero backoff procedure or it decides not to use the non-zero backoff procedure at block 174, then at block 178 it uses the same EDCA parameter settings as set in the EDCA parameter set element from the AP.

[0121] It should be noted that the STA can decide which EDCAFs use the non-zero backoff procedure and / or when the EDCAFs use the non-zero backoff procedure. Alternatively, the STA sends information to inform the AP that it supports the non-zero backoff procedure and the AP can decide for the STA whether to use the non-zero backoff procedure. The decision can also be made by the AP only or negotiated between the AP and the STA. It should be noted that the support of the non-zero backoff procedure can be a capability of the STA and the non-AP STA can send this capability information to the AP together with other capability information of the non-AP STA.

[0122] Figure 19 Figure illustrates an example embodiment 190 where the EDCA system of a STA uses some EDCAFs for the non-zero backoff procedure and other EDCAFs for the legacy backoff procedure to access the channel 210. For MAC service data units (MSDUs) or user priorities (UPs) 192, the AC queues are denoted as AC_VO 194, AC_VI 198, AC_BE 202, and AC_BK 206. As shown in the figure, the AC_VO EDCAF 196 uses the non-zero backoff procedure with a short AIFS while the EDCAFs 200, 204, and 208 of the other ACs use the legacy backoff procedure. In at least one implementation, the STA can use the parameters from the EDCA parameter set element received from the AP as shown in Table 3.

[0123] It should be noted that in at least one embodiment, the STA determines which EDCAFs will use the non-zero backoff procedure and / or when the EDCAFs will use the non-zero backoff procedure. Alternatively, the determination can be made by the AP only or negotiated between the AP and the STA.

[0124] Table 3 shows an example of using the same EDCA parameter set element to set the parameters for the legacy backoff procedure and the non-zero backoff procedure.

[0125] For those legacy STAs that do not support the non-zero backoff procedure, they should set the same EDCA parameters as set in the EDCA parameter set element received from the AP.

[0126] For those STAs that support the non-zero backoff procedure, if the EDCA of an AC is enabled to use the non-zero backoff procedure, it can set the AIFSN of that AC to a value smaller than the value in the received EDCA parameter set element. As shown in the table, the AIFSN of AC_VO is set to 1, which is smaller than the value in the EDCA parameter set element (i.e., 2). For the EDCA of other ACs, if the non-zero backoff procedure is not enabled, the EDCA parameters of these ACs should be the same as in the EDCA parameter set element. It should be noted that in at least one embodiment, CWmin and CWmax can be predetermined integers.

[0127] 5.4.1.2. New EDCA parameter set element for non-zero backoff

[0128] In at least one embodiment, a new EDCA parameter set element can be defined to set the parameters of the non-zero backoff procedure. The new EDCA parameter set element for the non-zero backoff procedure can be similar to Figure 22 set, and it can be carried by a frame similar to the frame described in Figure 21 The AP can send or broadcast a frame similar to Figure 21 to set the EDCA parameters for the legacy backoff procedure and the non-zero backoff procedure, respectively.

[0129] Figure 20 An example embodiment 230 is illustrated that uses the new EDCA parameter set element to set the parameters of the non-zero backoff procedure. The AP sends or broadcasts 232 a frame that includes EDCA parameter settings (e.g., EDCA parameter set element) for the legacy backoff procedure and EDCA parameter settings (e.g., non-zero backoff EDCA parameter set element) for the non-zero backoff procedure, respectively.

[0130] A check 234 determines whether the receiver STA supports the non-zero backoff procedure. If it is a legacy STA, it ignores the EDCA parameter settings for the non-zero backoff procedure at block 238.

[0131] However, if the receiver STA supports the non-zero backoff procedure, it uses the EDCA parameter settings for the non-zero backoff procedure in the received frame at block 236. It should be noted that when a STA receives the EDCA parameter settings for an AC of the non-zero backoff procedure from an AP, the selection as to whether the STA enables the non-zero backoff procedure for that AC can be mandatory or optional. When a STA uses the EDCA parameter settings for an AC of the non-zero backoff procedure, it can ignore the EDCA parameter settings for that AC of the legacy backoff procedure in the received frame. Note that a STA can enable or disable the non-zero backoff procedure in time.

[0132] Figure 21This diagram illustrates an example embodiment 250 of a frame that includes EDCA parameter settings for both the non-zero backoff procedure and the legacy backoff procedure. The Frame Control field indicates the frame type. The Duration field contains NAV information for CSMA / CA channel access. The Address 1 field contains the address of the frame's receiver. The Address 2 field contains the address of the STA transmitting the frame. The Address 3 field contains the BSSID of the receiver's BSS. The Sequence Control field indicates the frame's sequence number. The HT Control field indicates additional control information for the frame.

[0133] The EDCA Parameter Set element is configured to allow the AP to set this field to indicate the EDCA parameter settings for the legacy backoff procedure. When a STA receives this field, it can use the parameters in this field for the legacy backoff procedure. The Non-Zero Backoff EDCA Parameter Set element is configured to allow the AP to set this field to indicate the EDCA parameter settings for the non-zero backoff procedure. When a STA receives this field, it can use the parameters in this field for the non-zero backoff procedure. Figure 22 An example format for this field is shown in .

[0134] Figure 22 This diagram illustrates an example embodiment 270 of a non-zero backoff EDCA parameter set parameter. The Element ID field and the Element ID Extension field provide identification of the element, indicating that it is a non-zero backoff EDCA parameter set element. The Length field indicates the length of the element. The QoS Information field can be defined and configured to operate as in IEEE 802.11, as shown in FIG. 10 . The Updated EDCA Information field can be defined and utilized as in IEEE 802.11, as shown in FIG. 10 .

[0135] The AC Parameter Record field carries multiple AC Parameter Record fields, as shown in Figure 11. When an AC Parameter Record for an AC is included in this field, it indicates that the AP allows the receiver STA to use a non-zero backoff procedure for that AC. A STA can set this field to enforce the non-zero backoff procedure for that AC in a mandatory or optional manner. If the STA enables a non-zero backoff procedure for the AC indicated in this field, it sets the parameters for that AC to the same as those in the corresponding AC Parameter Record for the non-zero backoff procedure.

[0136] Figure 23An example embodiment 290 of an EDCA system for a STA that uses the EDCAFs for a non-zero backoff procedure and other EDCAFs for a legacy backoff procedure is illustrated. For MAC service data units (MSDUs) or user priority (UP) 292, AC queues are depicted for AC_Y 294, AC_X 298, AC_VO 302, AC_VI 306, AC_BE 310, and AC_BK 314. As shown in the figure, the EDCAFs 296, 300, and 304 for selected ACs, illustrated as AC_Y, AC_X, and AC_VO, use a non-zero backoff procedure with a short AIFS, while the EDCAFs 308, 312, and 316 for other ACs use a legacy backoff procedure to gain channel access 318. The STA can use the parameters from the EDCA parameter set element received from the AP for the legacy backoff procedure and the parameters from the non-zero backoff EDCA parameter set element received from the AP for the non-zero backoff procedure, e.g., as shown in Table 4.

[0137] In at least one implementation, the STA can determine (decide) which EDCAFs will use the non-zero backoff procedure and / or when the EDCAFs will use the non-zero backoff procedure. Alternatively, the decision can be made by the AP acting alone or by a negotiated decision between the AP and the STA.

[0138] It should also be noted that it is possible that when the STA decides to use the non-zero backoff procedure, the EDCAFs for all ACs of the STA should use the non-zero backoff procedure.

[0139] Table 4 shows an example of using the EDCA parameter set element to set the parameters for the legacy backoff procedure and using the non-zero backoff EDCA parameter set element to set the parameters for the non-zero backoff procedure.

[0140] For legacy STAs that do not support the non-zero backoff procedure, they should set the EDCA parameters as set in the EDCA parameter set element received from the AP.

[0141] For STAs that support the non-zero backoff procedure, if the EDCAF for an AC is enabled to use the non-zero backoff procedure, it should use the same parameters for that AC as in the non-zero backoff EDCA parameter set element received. As shown in the table, the AIFSN for AC X is set to 3, the CWmin is set to (aCWmin + l) / 4 - 1, the CWmax is set to (aCWmin + l) / 2 - 1, and the TXOP limit is set to 2 ms. It should be noted that aCWmin and aCWmax can be predetermined integers.

[0142] 5.4.2 Example

[0143] Figure 24 Figure illustrates an example embodiment 330 where a STA uses a shorter AIFS than the legacy STA procedure for the same AC to perform non-zero backoff. The figure illustrates the coexistence of the non-zero backoff procedure and the legacy backoff procedure. The network topology is shown in Figure 14 and depicts an AP 132, a STA1 134, and a STA2 136. In this example, AP1 and STA2 start the non-zero backoff procedure 334 for AC_i, while STA1 uses the legacy backoff procedure 336 for AC_i.

[0144] The STA first waits for the AIFS time before starting the countdown backoff 338. The AIFS for STA1's AC_i is one backoff slot time longer than the AIFS for AP1 and STA2. Therefore, AP1 and STA2 finish the AIFS time for AC_i earlier than STA1 and start / continue the countdown backoff slot. This makes the non-zero backoff procedure more likely to access the channel earlier (i.e., with higher priority) than the legacy backoff procedure for AC_i, especially when the two backoff procedures share the same CW to generate the random backoff slot. This also ensures that each time AP1 and STA2 enter CCA busy (or medium busy) after starting the countdown backoff slot, the backoff counter is decreased by at least 1.

[0145] However, as shown in this example, STA1 is allowed to access the channel immediately after the AIFS for its AC_i and start packet transmission 340, following the legacy backoff procedure. This shows that a STA using the legacy backoff procedure can still sometimes have a chance to get channel access earlier than a STA using the non-zero backoff procedure. Even in this scenario, AP1 and STA2 are guaranteed to decrease their backoff count by at least 1 before entering CCA busy. Note that the AIFS time for STA1's AC_i can be longer than the AIFS time for AP1 and STA2 by more than one backoff slot time. As can be seen on the right side of the figure, after STA1 finishes its transmission, AP1 and STA2 continue backoff 338 after the short AIFS, and in this case, STA2 counts down to zero 342 first, gains the channel and starts packet transmission 344.

[0146] Figure 25 Figure illustrates an example embodiment 370 where a STA uses a shorter AIFS than the legacy STA for the non-zero backoff procedure for the same AC. The figure shows another example of the coexistence of the non-zero backoff procedure and the legacy backoff procedure. The network topology is shown in Figure 14 and depicts the same STAs as in Figure 24

[0147] ​In this example, STA2 starts 372 a non-zero backoff process using the short AIFS 334 for AC_i. AP1 and STA1 use the legacy backoff process for AC_i with the legacy AIFS 336. As in the example shown in Figure 24 This example shows that a STA supporting a non-zero backoff process can potentially associate with a legacy AP and still use a non-zero backoff process, as compared to the example shown in Figure 18 The EDCA parameter settings for the non-zero backoff process can be the same or similar as described in

[0148] The STA first waits for the AIFS time before starting the countdown backoff. The AIFS for AC_i for AP1 and STA1 uses the legacy AIFS, which is one backoff slot time longer than the AIFS for STA2 starting 372 a non-zero backoff process with the short AIFS for AC_i. Thus, STA2 should finish the AIFS time for AC_i earlier than STA1 and start / continue the countdown backoff slot. This makes the non-zero backoff process more likely to access the channel earlier (i.e., with higher priority) than the legacy backoff process for AC_i, especially when both backoff processes share the same CW to generate the random backoff slot. This can also ensure that each time STA2 enters CCA busy (or medium busy) after starting the countdown backoff slot, the backoff counter decreases by at least 1.

[0149] However, as shown in this example, STA1 is allowed to access the channel immediately after the AIFS for its AC_i and start packet transmission 374 due to the rules of the legacy backoff process. Thus, it can be seen that a STA using the legacy backoff process can still potentially access the channel earlier than a STA using the non-zero backoff process. It should be noted that the AIFS time for AC_i for STA1 can be multiple backoff slots spanning a longer time than the AIFS time for AP1 and STA2.

[0150] After STA1 makes its transmission, it can be seen that STA2 makes the short AIFS 334 and starts the countdown 338, while AP1 uses the longer legacy AIFS 336. STA2 first counts down the backoff to 0 376 and starts its packet transmission 378.

[0151] 6. General scope of implementation

[0152] Embodiments of the technology can be illustrated herein with reference to flow diagrams of methods and systems in accordance with embodiments of the technology, and / or can also be implemented as processes, algorithms, steps, operations, formulas, or other computational descriptions of computer program products to illustrate. In this regard, each block or step of a flow diagram, and combinations of blocks (and / or steps) in a flow diagram, and any process, algorithm, step, operation, formula, or computational description, can be implemented by various means, such as hardware, firmware, and / or software including one or more computer program instructions embodied on computer-readable program code. As will be realized by those skilled in the art, any such computer program instructions can be executed on one or more computer processors (including without limitation a general- purpose computer or special-purpose computer) or other programmable processing apparatus to produce a machine, such that the computer program instructions which execute on the computer processor(s) or other programmable processing apparatus create means for implementing the functions specified in the flow diagram block(s) or step(s).

[0153] Accordingly, blocks of the flow diagrams, and processes, algorithms, steps, operations, formulas, or computational descriptions illustrated herein support combinations thereof for performing the specified functions, combinations of steps for performing the specified functions, and computer program instructions (such as embodied on computer-readable program code logic) for performing the specified functions. It will also be understood that each block of the flow diagrams, and any processes, algorithms, steps, operations, formulas, or computational descriptions illustrated herein, and combinations thereof, can be implemented by special-purpose hardware-based computer systems which perform the specified functions or steps, or combinations of special-purpose hardware and computer-readable program code.

[0154] Further, these computer program instructions (such as embodied on computer-readable program code) can also be stored in one or more computer-readable memory or storage devices that can direct a computer processor or other programmable processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory or storage device produce an article of manufacture including instruction means which implement the function specified in the flow diagram block(s). The computer program instructions can also be executed by a computer processor or other programmable processing apparatus to cause a series of operational steps to be performed in the computer processor or other programmable processing apparatus, thereby producing a computer-implemented process so that the instructions which execute in the computer processor or other programmable processing apparatus provide steps for implementing the functions specified in the flow diagram block(s), process, algorithm, step, operation, formula, or computational description.

[0155] It should also be appreciated that the term "program" or "executable program" as used herein refers to one or more instructions that can be executed by one or more computer processors to perform one or more functions described herein. The instructions can be embodied in software, firmware, or a combination of software and firmware. The instructions can be stored locally on a device in non-transitory media, or can be stored remotely, such as on a server, or all or part of the instructions can be stored locally and remotely. The remotely stored instructions can be downloaded (pushed) to the device by user initiation, or automatically downloaded (pushed) to the device based on one or more factors.

[0156] It should also be appreciated that the terms processor, hardware processor, computer processor, central processing unit (CPU), and computer are used synonymously herein to refer to a device capable of executing instructions and communicating with input / output interfaces and / or peripheral devices, and the terms processor, hardware processor, computer processor, CPU, and computer are intended to encompass one or more devices, single-core and multi-core devices, and variations thereof.

[0157] In light of the description herein, it should be appreciated that the disclosure encompasses a variety of implementations of the described technology, including but not limited to the following implementations:

[0158] An apparatus for wireless communication in a network, the apparatus comprising: (a) wireless communication circuitry of a wireless station (STA) as an access point (AP) or a non-AP STA, the wireless communication circuitry configured to wirelessly communicate with other wireless stations (STAs) as APs or non-AP STAs over a channel on a wireless local area network (WLAN) in which packets carry frames; (b) a processor coupled to the wireless communication circuitry to operate as a STA on the WLAN; (c) a non-transitory memory storing instructions executable by the processor to communicate with other STAs; and (d) wherein the instructions, when executed by the processor, perform one or more steps comprising: (d)(i) initiating a non-zero backoff procedure by setting a backoff counter to a random value greater than or equal to at least one backoff slot when starting to contend for the channel; (d)(ii) counting down the backoff counter according to channel conditions; and (d)(iii) accessing the channel when the backoff counter reaches zero.

[0159] An apparatus for wireless communication in a network, the apparatus comprising: (a) a wireless communication circuitry as a wireless station (STA) operating as an access point (AP) or a non-AP STA, the wireless communication circuitry configured to wirelessly communicate with other wireless stations (STAs) as APs or non-AP STAs over a channel on a wireless local area network (WLAN) in which packets carry frames; (b) a processor coupled to the wireless communication circuitry to operate as a STA on the WLAN; (c) a non-transitory memory storing instructions executable by the processor to communicate with other STAs; and (d) wherein the instructions, when executed by the processor, perform one or more steps comprising: (d)(i) utilizing a non-zero backoff procedure for channel contention when the STA supports the non-zero backoff procedure, and utilizing a legacy backoff procedure for channel contention when the STA does not support the non-zero backoff procedure; and (d)(ii) setting an AIFS time for an AC to a short AIFS time that is shorter in length than an AIFS time utilized by the AC when using a legacy backoff procedure to provide the non-zero backoff procedure with a higher probability of accessing the channel earlier than a STA using the legacy backoff procedure.

[0160] A method of wireless communication in a network, comprising: (a) performing wireless communication from a wireless station (STA) operating as an access point (AP) or a non-AP STA to other wireless stations (STAs) as APs or non-AP STAs on a wireless local area network (WLAN) in which packets carry frames; (b) initiating a non-zero backoff procedure by setting a backoff counter to a random value greater than or equal to at least one backoff slot when beginning to contend for a channel; (c) counting down the backoff counter according to channel conditions; and (d) accessing the channel when the backoff counter reaches zero.

[0161] A wireless communication apparatus performing packet transmission in which CSMA / CA or EDCA is applied and packets carry frames, comprising: a STA not supporting a non-zero backoff procedure utilizing a legacy backoff procedure for channel contention; a STA supporting a non-zero backoff procedure can utilize the non-zero backoff procedure for channel contention; and a STA utilizing a non-zero backoff procedure for an AC can set an AIFS time for the AC to be shorter than an AIFS time utilized by a STA utilizing a legacy backoff procedure for the same AC to cause the non-zero backoff procedure to have a higher probability of accessing the channel earlier.

[0162] A wireless communication apparatus to perform packet transmission with CSMA / CA or EDCA and packets carrying frames, comprising: a STA initializing a non-zero backoff counter to a random value greater than or equal to 1 (at least one backoff slot); the STA counting down the backoff counter according to channel conditions; and the STA accessing the channel when the backoff counter equals 0.

[0163] The apparatus or method of any preceding implementation, wherein the STA is configured to use either the non-zero backoff procedure of an access category (AC) or a legacy backoff procedure that does not use a non-zero backoff procedure.

[0164] The apparatus or method of any preceding implementation, wherein the STA using the non-zero backoff procedure of an access category (AC) sets an arbitration inter-frame space (AIFS) time to an amount less than an AIFS time utilized by a legacy backoff procedure that does not use a non-zero backoff procedure.

[0165] The apparatus or method of any preceding implementation, wherein the station operating in the role of an AP reuses an enhanced DCF channel access (EDCA) parameter set by transmitting the EDCA parameter set to its associated STAs to set the non-zero backoff procedure.

[0166] The apparatus or method of any preceding implementation, wherein the station operating in the role of an AP defines a new element in a communication frame to transmit at least one EDCA parameter set for its associated STAs to set the EDCA parameters of the non-zero backoff procedure.

[0167] The apparatus or method of any preceding implementation, wherein the station determines whether to enable the non-zero backoff procedure of one or more access categories (ACs) without input from an AP.

[0168] The apparatus or method of any preceding implementation, wherein the station operating as an AP determines whether to enable the non-zero backoff procedure of one or more access categories (ACs) for its associated STAs.

[0169] The apparatus or method of any preceding implementation, wherein the station is capable of switching between enabling and disabling the non-zero backoff procedure in different time periods.

[0170] The apparatus or method of any preceding implementation, wherein the station determines whether to enable the non-zero backoff procedure of one or more access categories (ACs) without input from an AP.

[0171] The apparatus or method of any preceding implementation, wherein the station operating as an AP determines whether to enable the non-zero backoff procedure of one or more access categories (ACs) for its associated STAs.

[0172] The apparatus or method in accordance with any of the previous implementations, wherein the station operating in the role of an AP reuses the EDCA parameter set by transmitting the EDCA parameter set to its associated STAs to set the non-zero backoff procedure.

[0173] The apparatus or method in accordance with any of the previous implementations, wherein an AC using a non-zero backoff procedure for the AC can set its AIFSN to be smaller than the AIFSN of a legacy backoff procedure.

[0174] The apparatus or method in accordance with any of the previous implementations, wherein an AP can reuse the EDCA parameter set elements to set the EDCA parameters of a non-zero backoff procedure on its associated STAs.

[0175] The apparatus or method in accordance with any of the previous implementations, wherein an AP can define new elements to set the EDCA parameters of a non-zero backoff procedure on its associated STAs.

[0176] The apparatus or method in accordance with any of the previous implementations, wherein a STA can decide on its own whether to enable the non-zero backoff procedure for an AC.

[0177] The apparatus or method in accordance with any of the previous implementations, wherein an AP can decide whether to enable the non-zero backoff procedure for an AC on its associated STAs.

[0178] The apparatus or method in accordance with any of the previous implementations, wherein a STA can enable and disable the non-zero backoff procedure in time.

[0179] The apparatus or method in accordance with any of the previous implementations, wherein a STA supporting the non-zero backoff procedure can decide on its own whether to use the non-zero backoff procedure for one or more ACs.

[0180] The apparatus or method in accordance with any of the previous implementations, wherein an AP can force its associated STAs supporting the non-zero backoff procedure to use the non-zero backoff procedure for one or more ACs.

[0181] The apparatus or method in accordance with any of the previous implementations, wherein an AP can reuse the EDCA parameter set elements to set the EDCA parameters of a non-zero backoff procedure on its associated STAs.

[0182] The apparatus or method in accordance with any of the previous implementations, wherein an AP can define new elements to set the EDCA parameters of a non-zero backoff procedure on its associated STAs.

[0183] The apparatus or method in accordance with any of the previous implementations, wherein a STA setting a short AIFS for the non-zero backoff procedure for an AC cannot set an AIFS time shorter than the PIFS time.

[0184] The apparatus or method in accordance with any of the previous implementations, wherein a STA can enable and disable the non-zero backoff procedure in time.

[0185] The term "implement," as used herein, is intended to include, without limitation, embodiments, examples, or other implementations of the technology described herein.

[0186] As used herein, the singular forms "a," "an," and "the" can include plural referents unless the context clearly dictates otherwise. Unless expressly stated to the contrary, use of the singular form in reference to an object in the context of using the indefinite article (e.g., "a" or "an"), is not intended to mean "only one" or "just one," but rather "one or more."

[0187] Phrasing such as "A, B, and / or C," when preceding a list of items, overlaps with the contention that "A, B, and C" are any combinatorial set of the items A, B, and C. Phrasing such as "at least one of A, B, and C," and "one or more of A, B, or C" indicates that a list including at least one of the items A, B, or C is acceptable. Further, use of the term "at least one" followed by a list of items means the list is an open-ended list.

[0188] References within the disclosure to "an embodiment," "at least one embodiment," or similar language indicate that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the disclosure. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, or to one in particular separate embodiment. The embodiments are not mutually exclusive, but can be combined in any suitable manner. Embodiment language should be interpreted in context with the rest of the specification and not as a means to vitalize one particular embodiment over others.

[0189] The term "set," as used herein, refers to a collection of one or more objects. Thus, for example, a set of objects can include a single object or multiple objects.

[0190] Relative terms such as first and second, top and bottom, and the like can be used herein for ease of reference only and do not necessarily connote any actual relationship between or by the entities or actions so described.

[0191] The terms "comprises," "comprising," "has," "having," "includes," "including," "contains," "containing," "wherein," "where," "whereby," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises, has, includes, contains a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by "comprises... a," "has... a," "includes... a," or "contains... a" does not, without a further limitation, exclude additional identical elements of the process, method, article, or apparatus.

[0192] As used herein, the terms "approximately," "about," "substantially," "essentially," and "approximately," or any other version thereof, are used to describe and account for small variations. When used in connection with an event or circumstance, these terms can refer to instances in which the event or circumstance occurs exactly, as well as instances in which the event or circumstance occurs approximately. When used in connection with a numerical value, these terms can refer to a range of variation of less than or equal to ±10% of that numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, "substantially" aligned can refer to a range of angular variation of less than or equal to ±10°, such as less than or equal to ±5°, less than or equal to ±4°, less than or equal to ±3°, less than or equal to ±2°, less than or equal to ±1°, less than or equal to ±0.5°, less than or equal to ±0.1°, or less than or equal to ±0.05°.

[0193] Additionally, quantities, ratios and other numerical values in this disclosure can sometimes be presented in a range format. It is to be understood that the use of such range format is merely for convenience and brevity and should be interpreted - in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges within that range as if each numerical value and sub-range is explicitly recited. For example, a ratio ranging from about 1 to about 200 should be interpreted to include not only the explicitly recited limits of about 1 and about 200, but also the individual numerical values such as about 2, about 3 and about 4, and sub-ranges such as from about 10 to about 50, from about 20 to about 100, and the like.

[0194] The term "coupled" as used herein is defined as connected, although not necessarily directly, and not necessarily mechanically. A device or structure that is "configured" in a certain way is configured in at least that way, but can also be configured in ways that are not listed.

[0195] The benefits, advantages, solutions to problems, and any element that can cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential feature or element of the technologies described herein or any or all the claims. It should also be understood that the specific order or hierarchy of steps in the methods disclosed is an example of an implementation that can be implemented in some

[0196] In addition, in the above disclosed, for the sake of simplifying the disclosure, individual features in various embodiments can be gathered together. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than explicitly recited in each claim. The inventive subject matter can lie in fewer than all features of a single disclosed embodiment.

[0197] To enable the reader to quickly determine the nature of the present technology disclosed, a summary of the disclosure is provided. The summary is submitted with the understanding that it will not be used to interpret or limit the scope or the meaning of the claims.

[0198] It is appreciated that the practice of some jurisdictions can require the deletion of one or more portions of the present disclosure after the filing of the present application. Accordingly, the reader should consult the filed application for the original content of the present disclosure. Any deletions of content of the present disclosure should not be interpreted as an abandonment, disclaimer, or dedication to the public of any subject matter of the originally filed application.

[0199] The following claims are hereby incorporated into the present disclosure, each claim standing on its own as a separately claimed subject matter.

[0200] While the specification contains many specifics, these should not be construed as limiting the scope of the disclosure but as merely providing illustrations of some of the presently preferred embodiments. Thus, it will be appreciated that the scope of the disclosure encompasses other embodiments apparent from the following description.

[0201] All structural and functional equivalents to the elements of the disclosed embodiments with known or conventional methods for accomplishing substantially the same results are expressly incorporated herein by reference and are meant to be encompassed by the claims. Moreover, none of the elements of the disclosure are intended to be dedicated to the public, regardless of whether the element is explicitly recited in the claims. No claim element is to be construed as a mere means for accomplishing an identified function without a corresponding function recited in a claim. The functions described herein are intended to be merely exemplary and are not intended to limit the scope of the claims to these functions.

[0202] Table 1 UP to AC mapping

[0203]

[0204] Table 2 Example of default parameter set

[0205]

[0206] Table 3 Example: AP sends same EDCA parameter set to associated STAs

[0207]

[0208] Table 4 Example: AP sends same EDCA parameter set to associated STAs

[0209]

Claims

1. An apparatus as a wireless station (STA) for wireless communication in a network, wherein the wireless station (STA) is configured to operate as an access point (AP) or a non-AP STA, the apparatus comprising: (a) a wireless communication circuit configured to perform wireless communication with other wireless stations (STAs) that are APs or non-AP STAs over a channel on a wireless local area network (WLAN) in which packets carry frames; (b) a processor coupled to the wireless communication circuitry to operate as a STA on a WLAN; (c) a non-transitory memory storing instructions executable by the processor to communicate with other STAs; as well as (d) wherein the instructions, when executed by the processor, perform one or more steps comprising: (i) initiating a non-zero backoff procedure by setting the backoff counter to a random value greater than or equal to at least one backoff slot at the start of contention for the channel; (ii) counting down the backoff counter according to channel conditions; as well as (iii) accessing the channel when the backoff counter reaches zero, wherein the STA using the non-zero backoff procedure of access class AC sets the arbitration interframe space (AIFS) time to an amount smaller than the AIFS time utilized by the AC in a conventional backoff procedure not using the non-zero backoff procedure.

2. The apparatus of claim 1, wherein the STA is configured to operate in accordance with IEEE 802.

11.

3. The apparatus of claim 1 , wherein the STA is configured to use the non-zero backoff procedure with carrier sense multiple access / collision avoidance (CSMA / CA), distributed coordination function (DCF), and / or enhanced DCF channel access (EDCA).

4. The apparatus of claim 1 , wherein the STA is configured to use either the non-zero backoff procedure of access categories AC or a legacy backoff procedure that does not use a non-zero backoff procedure.

5. The apparatus of claim 1, wherein the station operating in the role of an AP reuses an Enhanced DCF Channel Access (EDCA) parameter set by transmitting an Enhanced DCF Channel Access (EDCA) parameter set to its associated STAs to set the non-zero backoff procedure.

6. The apparatus of claim 1, wherein the station operating in the role of an AP performs defining a new element in a communication frame to transmit at least one EDCA parameter set for its associated STAs, thereby setting EDCA parameters for a non-zero backoff process.

7. The apparatus of claim 1, wherein the station determines whether to enable a non-zero backoff procedure for one or more access categories AC without input from an AP.

8. The apparatus of claim 1, wherein the station operating as an AP determines whether to enable a non-zero backoff procedure for one or more access categories AC for its associated STAs.

9. The apparatus of claim 1, wherein the station is capable of switching between enabling and disabling the non-zero backoff procedure in different time periods.

10. An apparatus as a wireless station (STA) for wireless communication in a network, wherein the wireless station (STA) is configured to operate as an access point (AP) or a non-AP STA, the apparatus comprising: (a) a wireless communication circuit configured to perform wireless communication with other wireless stations (STAs) that are APs or non-AP STAs over a channel on a wireless local area network (WLAN) in which packets carry frames; (b) a processor coupled to the wireless communication circuitry to operate as a STA on a WLAN; (c) a non-transitory memory storing instructions executable by the processor to communicate with other STAs; as well as (d) wherein the instructions, when executed by the processor, perform one or more steps comprising: (i) when the STA supports a non-zero backoff procedure, performing channel contention using the non-zero backoff procedure, and when the STA does not support a non-zero backoff procedure, performing channel contention using a conventional backoff procedure; as well as (ii) when a non-zero backoff procedure is used, setting the arbitration interframe space (AIFS) time of access category AC to a shorter AIFS time than the AIFS time used by the AC when a conventional backoff procedure is used, so as to provide the non-zero backoff procedure with a higher probability of accessing the channel earlier than a STA using the conventional backoff procedure.

11. The apparatus of claim 10, wherein the STA is configured to operate in accordance with IEEE 802.

11.

12. The apparatus of claim 10, wherein the STA is configured to use the non-zero backoff procedure with carrier sense multiple access / collision avoidance (CSMA / CA), distributed coordination function (DCF), and / or enhanced DCF channel access (EDCA).

13. The apparatus of claim 10, wherein the station determines whether to enable a non-zero backoff procedure for one or more access categories AC without input from an AP.

14. The apparatus of claim 10, wherein the station operating as an AP determines whether to enable a non-zero backoff procedure for one or more access categories AC for its associated STAs.

15. The apparatus of claim 10, wherein the station operating in the role of an AP reuses an Enhanced DCF Channel Access (EDCA) parameter set by transmitting an Enhanced DCF Channel Access (EDCA) parameter set to its associated STAs to set the non-zero backoff procedure.

16. The apparatus of claim 10, wherein the station operating in the role of an AP performs defining a new element in a communication frame to transmit at least one EDCA parameter set for its associated STAs, thereby setting EDCA parameters for a non-zero backoff process.

17. The apparatus according to claim 10, wherein the STA performs setting a short AIFS time for a non-zero backoff procedure of the AC, and limits the short AIFS time to be equal to or greater than the PIFS time.

18. The apparatus of claim 10, wherein the station is capable of switching between enabling and disabling the non-zero backoff procedure in different time periods.

19. A method of wireless communication in a network performed by a wireless station (STA), the wireless station (STA) being configured to operate as an access point (AP) or a non-AP STA, the method comprising: (a) performing wireless communications to other wireless stations STA that are APs or non-AP STAs over a wireless local area network WLAN in which the packets carry frames; (b) initiating a non-zero backoff procedure by setting the backoff counter to a random value greater than or equal to at least one backoff slot at the start of contention for the channel; (c) counting down the backoff counter according to channel conditions; as well as (d) access the channel when the backoff counter reaches zero, The method further comprises: When a non-zero backoff process is used, the arbitration interframe space (AIFS) time of the access category AC is set to a short AIFS time that is shorter than the AIFS time used by the AC when a traditional backoff process is used, so as to provide the non-zero backoff process with a higher probability of accessing the channel earlier than STAs using the traditional backoff process.

20. The method of claim 19, further comprising: When the STA supports a non-zero backoff process, the non-zero backoff process is used to perform channel contention, and when the STA does not support the non-zero backoff process, the traditional backoff process is used to perform channel contention.

21. The method of claim 19, wherein the station or AP determines whether to enable a non-zero backoff procedure for one or more access categories AC.

22. The method of claim 19, wherein the station is capable of switching between enabling and disabling the non-zero backoff procedure at different time periods.

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