Communication device and communication method

Abstract

A communication apparatus and a communication method are described. An integrated circuit is disclosed that controls a process of a communication apparatus acting as a 20MHz operator station, comprising: at least one input for receiving input; and control circuitry coupled to the at least one input, controlling the process including: receiving a trigger frame for allocating resource units (RUs) for random access and other frames including random access parameter elements, the random access parameter elements including a first field indicating the minimum value of the OFDMA contention window (OCW) (OCWmin), wherein the RUs include at least one RU restricted to use by the 20MHz operator station; and using OCWmin to control a random access UORA process based on uplink OFDMA, comprising: setting the OBO counter to zero if the OFDMA backoff OBO counter is not greater than the number of available RUs for random access in the trigger frame, the available RUs being RUs not restricted to use by the 20MHz operator station; and decrementing the OBO counter by the number of available RUs for random access if the OBO counter is greater than the number of available RUs.

Description

[0001] This application is a divisional application of Chinese invention patent application filed on August 21, 2017, with application number 201780048347.5, entitled "Communication Device and Communication Method", and filed by Panasonic Corporation (USA). Technical Field

[0002] This invention generally relates to communication devices and communication methods. Background Technology

[0003] The IEEE (Institute of Electrical and Electronics Engineers) 802.11 Working Group is developing the 802.11ax HE (High-Efficiency) WLAN (Wireless Local Area Network) air interface to achieve a significant increase in actual throughput implemented by users in high-density scenarios. OFDMA (Orthogonal Frequency Division Multiple Access) multi-user transmission has been envisioned as one of the most important features in 802.11ax. OFDMA is a multiple access scheme that performs multiple operations on data streams to or from multiple users on time and frequency resources of an OFDM (Orthogonal Frequency Division Multiplexing) system.

[0004] Research is underway to implement frequency scheduling for OFDMA multi-user transmission in 802.11ax, typically based on RUs (Resource Units). An RU comprises multiple consecutive subcarriers. According to the frequency scheduling, a radio communication access point device (hereinafter referred to as an "access point" or "AP") adaptively assigns an RU to multiple STAs based on the receive quality of the frequency band of a radio communication station device (hereinafter referred to as a "terminal station" or "STA"). This allows for maximum multi-user diversity and very efficient communication.

[0005] However, certain conditions have been imposed on uplink (UL) multi-user OFDMA transmissions. For example, all STAs participating in an UL multi-user OFDMA transmission need to synchronize their transmissions to start and end at the same time. In 802.11ax, this is achieved by the AP sending a special control frame called a trigger frame. The trigger frame carries information such as the identification information of each STA that can participate in the UL multi-user transmission, the transmission duration, the RU allocation for each STA, and other useful information. The STAs indicated in the trigger frame transmit their respective frames on their assigned RUs after fixed time intervals, such as SIFS (Short Interframe Spacing, from the end of the trigger frame). This arrangement is effective when the AP has sufficient information about the STAs participating in the UL multi-user transmission (such as buffer status and STA operational status). However, there are situations where the AP may not have enough information about how effectively the STAs can perform RU allocation. In such cases, it is beneficial to allocate RUs to STAs according to their actual needs and allow STAs to contend for RUs. To meet these requirements, the UL OFDMA-based Unlimited Access (UORA) mechanism was introduced in 802.11ax.

[0006] [List of Citations]

[0007] [Non-patent literature]

[0008] [NPL 1] IEEE 802.11-15 / 0132r17, TGax specification framework, May 2016

[0009] [NPL 2] IEEE 802.11-16 / 0024r1, Proposed TGax Draft Specification, March 2016

[0010] [NPL 3] IEEE 802.11-15 / 1105r0, Random Access Method Based on UL OFDMA, September 2015

[0011] [NPL 4] IEEE 802.11-15 / 1137r1, OFDMA triggered random access observation, September 2015

[0012] [NPL 5] IEEE 802.11-16 / 0780r1, CID: Section 9.3.1.23 Trigger Frame Format, April 2016

[0013] [NPL 6] IEEE 802.11-16 / 0806r0, HE variant HT control-buffer status report, July 2016

[0014] [NPL 7] IEEE 802.11-15 / 1107r0, random access power saving, September 2015

[0015] [NPL 8] IEEE 802.11-16 / 0907r3, 20MHz-only devices in 11ax, July 2016

[0016] [NPL 9] IEEE 802.11-16 / 0906r0, RU Limitation for 20MHz Operating Devices in OFDMA, July 2016

[0017] [NPL 10] IEEE 802.11-16 / 1162r3, Comment Decision on OFDMA Random Access Retransmission, September 2016

[0018] [NPL 11] IEEE 802.11-16 / 1158r0, Comment Decision on OFDMA Random Access Methods, September 2016

[0019] [NPL 12] IEEE 802.11-16 / 1222r1, CID resolution for random access based on UL OFDMA, September 2016

[0020] [NPL 13] IEEE 802.11-16 / 1516r1, Random Access CID, November 2016

[0021] [NPL 14] IEEE 802.11-16 / 1458r0, featuring power-saving CID resolution for random access based on UL OFDMA, November 2016

[0022] [NPL 15] IEEE 802.11-16 / 1477r2, CC23 Recommendation Resolution (Update) TWT Elements, November 2016 Summary of the Invention

[0023] In 802.11ax, some RUs in 40, 80, 80+80, or 160MHz OFDMA operations are restricted to STAs operating at 20MHz. Currently, there are no rules regarding how RUs are assigned by the AP for random access in the trigger frame. In some cases, no RU is assigned for random access in the trigger frame for use by a 20MHz operating STA; therefore, when a trigger frame for random access is received, the 20MHz operating STA cannot reach the AP using the UORA mechanism.

[0024] A non-limiting and exemplary embodiment of the present invention provides a communication device that can help allow a 20MHz operating STA to obtain the opportunity to reach an AP using the UORA mechanism.

[0025] In one general aspect, the technology disclosed herein is characterized by a communication apparatus comprising: a receiving unit that receives a trigger frame for allocating resource units (RUs) for random access, and another frame including random access parameter elements, which include a first field indicating a minimum value (OCWmin) of the OFDMA contention window (OCW) and a second field indicating a maximum value (OCWmax) of the OCW; and control circuitry that uses OCWmin and OCWmax to control the uplink OFDMA-based random access (UORA) process.

[0026] In another general aspect, the technology disclosed herein is characterized by an integrated circuit for controlling a communication device as a 20MHz operating station, the integrated circuit comprising: at least one input receiving the input; and control circuitry coupled to the at least one input, the control comprising the following operations: receiving a trigger frame for allocating resource units (RUs) for random access and other frames including random access parameter elements, the random access parameter elements including a first field indicating the minimum value of the OFDMA contention window (OCW) (OCWmin), wherein the RUs include at least one RU restricted to use as a 20MHz operating station; and using OCWmin to control a random access UORA process based on uplink OFDMA, the UORA process comprising: setting the OBO counter to zero if the OFDMA backoff OBO counter is not greater than the number of available RUs for random access in the trigger frame, the available RUs being RUs not restricted to use as a 20MHz operating station; and decrementing the OBO counter if the OBO counter is greater than the number of available RUs for random access.

[0027] These general and specific aspects can be implemented using devices, systems, methods, and computer programs, as well as any combination of devices, systems, methods, and computer programs.

[0028] By utilizing the apparatus and method described in this disclosure, a 20MHz operating STA can gain the opportunity to reach an AP using the UORA mechanism.

[0029] Further benefits and advantages of the disclosed embodiments will become apparent from the description and accompanying drawings. Various embodiments and features in the description and drawings may be obtained individually, without all of them needing to be provided to obtain one or more of these benefits and / or advantages. Attached Figure Description

[0030] Figure 1 This is a diagram illustrating a multi-user wireless communication system.

[0031] Figure 2This is a flowchart illustrating an example UL OFDMA random access method operated by a STA.

[0032] Figure 3 This is a diagram illustrating an example of multi-user frame switching related to UL OFDMA-based random access.

[0033] Figure 4 This is a diagram illustrating an example format of the trigger frame.

[0034] Figure 5 This is a flowchart illustrating a random access method based on a first example ULOFDMA operated by a 20MHz STA according to a first embodiment of the present disclosure.

[0035] Figure 6 This is a flowchart illustrating a random access method based on example UL OFDMA operated by a non-20MHz STA according to a first embodiment of the present disclosure.

[0036] Figure 7 This is a diagram illustrating a first example of multi-user frame switching related to UL OFDMA-based random access according to a first embodiment of the present disclosure.

[0037] Figure 8 This is a flowchart illustrating a random access method based on a second example ULOFDMA operated by a 20MHz STA according to a first embodiment of the present disclosure.

[0038] Figure 9 This is a diagram illustrating a second example of multi-user frame switching related to UL OFDMA-based random access according to a first embodiment of this disclosure.

[0039] Figure 10 This is a diagram illustrating an example format of a trigger frame according to a first embodiment of the present disclosure.

[0040] Figure 11 This is a diagram illustrating an example format of random access parameter elements based on UL OFDMA according to a first embodiment of this disclosure.

[0041] Figure 12 This is a flowchart illustrating a random access method based on a first example ULOFDMA operated by a non-20MHz STA according to a second embodiment of the present disclosure.

[0042] Figure 13 This is a diagram illustrating a first example of multi-user frame switching related to UL OFDMA-based random access according to a second embodiment of this disclosure.

[0043] Figure 14This is a flowchart illustrating a random access method based on a second example ULOFDMA operated by a non-20MHz STA according to a second embodiment of the present disclosure.

[0044] Figure 15 This is a diagram illustrating a second example of multi-user frame switching related to UL OFDMA-based random access according to a second embodiment of this disclosure.

[0045] Figure 16 This is a diagram illustrating an example format of a trigger frame according to a second embodiment of the present disclosure.

[0046] Figure 17 This is a diagram illustrating an example format of a TWT element.

[0047] Figure 18 This is a diagram illustrating an example format of a TWT element according to a third embodiment of the present disclosure.

[0048] Figure 19A This is a simplified block diagram of the example STA based on this disclosure.

[0049] Figure 19B This is a detailed block diagram of the example STA based on this disclosure.

[0050] Figure 20A This is a simplified block diagram of an example AP based on this disclosure.

[0051] Figure 20B This is a detailed block diagram of the example AP based on this disclosure. Detailed Implementation

[0052] This disclosure can be better understood with the aid of the following figures and embodiments. The embodiments described herein are merely exemplary in nature and are used to illustrate some possible applications and uses of this disclosure, and should not be regarded as limiting the disclosure with respect to alternative embodiments not expressly described herein.

[0053] In any wireless communication system, a wide variety of devices can be part of the wireless network, each differing in traffic requirements, device capabilities, power type, and so on. Some types of devices may have high bandwidth requirements, high QoS (Quality of Service) requirements in areas such as latency or transmission success rate. However, they may be less concerned about power consumption because they may be powered by a mains power source or have a large battery (e.g., laptops). Another type of device may have lower bandwidth requirements and less stringent QoS requirements, but may be relatively more concerned about power consumption (e.g., mobile phones). Yet another type of device may have low bandwidth requirements and a very low duty cycle, but may be very sensitive to power consumption due to extremely small batteries or extremely long expected lifespans (e.g., sensors used for remote sensing).

[0054] In many wireless communication systems, there will be one or more central controllers that determine the wireless network coverage area, wireless frequency channels, device admission policies, coordination with other neighboring wireless networks, and often also act as gateways to the back-end infrastructure network. Examples of central controllers are base stations or eNBs in cellular wireless networks or access points (APs) in WLANs.

[0055] While the techniques described in this disclosure can be applied to many wireless communication systems, the remainder of the description in this disclosure is for illustrative purposes and is based on the IEEE 802.11 WLAN system and its related terminology. This should not be construed as limiting this disclosure with regard to alternative wireless communication systems. In IEEE 802.11-based WLANs, most networks operate in infrastructure mode, meaning that all or most of the traffic in the network needs to pass through an Access Point (AP). Therefore, any STA wishing to join the WLAN must first negotiate network membership with the AP through a process known as association and authentication.

[0056] Figure 1 The illustration shows an example wireless network 100 including AP 110 and multiple STAs. STA2 124 and STA6 134 represent a device class with high bandwidth and potentially high QoS requirements, as well as relatively low power consumption requirements, which can operate with channel widths of 20, 40, 80, 80+80, or 160 MHz. STA1 122 and STA4 132 represent another device class, which may also have high bandwidth and potentially high QoS requirements, but is relatively more concerned with power consumption, and can operate with channel widths of 20, 40, or 80 MHz. At the other extreme, STA3 126 and STA5 136 represent another device class that may have low bandwidth requirements but may be very sensitive to power consumption, and may only be able to operate with a 20 MHz channel width. STAs of this device class may be referred to as "20 MHz Operating STAs" or "20 MHz Only STAs". Note that 20 MHz Operating STAs (e.g., STA3 126 and STA5 136) operate only in the primary 20 MHz channel. In other words, a 20MHz operating STA cannot use a RU that is not located in the main 20MHz channel. In addition, non-20MHz operating STAs (e.g., STA1 122, STA2 124, STA4 132, and STA6 134) can reduce their operating channel width to 20MHz for power saving purposes through a so-called operating mode indication process.

[0057] The RU tone mapping in the 20MHz bandwidth is inconsistent with that in the 40, 80, 80+80, or 160MHz bandwidths. Due to the misalignment of RU locations, some RUs may cause significant performance loss or interference to adjacent RUs when a 20MHz operating STA participates in 40, 80, 80+80, or 160MHz downlink (DL) or ULOFDMA operations. To improve throughput and interoperability, some RUs in 40, 80, 80+80, or 160MHz OFDMA operations are restricted to 20MHz operating STAs. More specifically, in 40MHz DL or UL OFDMA operations, 2 out of 18 26-tone RUs (i.e., 5%) will be restricted to 20MHz operating STAs. In 80MHz DL or UL OFDMA operations, 7 out of 37 26-tone RUs (i.e., 19%), 2 out of 16 52-tone RUs (i.e., 12.5%), and 2 out of 8 106-tone RUs (i.e., 25%) should not be assigned to 20MHz operating STAs. For 80+80 or 160MHz DL or UL OFDMA operations, 14 out of 74 26-tone RUs (i.e., 19%), 4 out of 32 52-tone RUs (i.e., 12.5%), and 4 out of 16 106-tone RUs (i.e., 25%) should not be allocated to 20MHz operating STAs. Furthermore, in 40, 80, 80+80, or 160MHz UL OFDMA operations, 242-tone RUs should not be allocated to 20MHz operating STAs. Clearly, limiting the number of RUs used for 20MHz operating STAs in 40, 80, 80+80, or 160MHz OFDMA operations is not insignificant.

[0058] Random Access Based on UL OFDMA

[0059] UORA is a mechanism used by a STA to randomly select a RU (Remote Root) assigned by AP 110 for random access during a request trigger frame. STAs using the UORA mechanism maintain an internal counter called the OFDMA Backoff (OBO) counter. The OFDMA contention window (OCW) is an integer with an initial value of OCWmin and an upper limit of OCWmax. AP 110 reports the values ​​of OCWmin and OCWmax used for UORA operations to the STA.

[0060] Figure 2 The illustration shows an example UORA method 200 operated by a STA. UORA method 200 begins when the STA receives a trigger frame for random access from AP 110. Details of the example UORA method will be described later.

[0061] Figure 4The illustration shows an example format for trigger frame 400, which includes a common information field 410 and one or more user information fields 420. The common information field 410 includes a trigger type subfield 412, a concatenation indication subfield 414, and an optional trigger-related common information subfield 416. The trigger type subfield 412 indicates the type of trigger frame 400, such as basic trigger, beamforming report polling trigger, BSRP (Buffer Status Report Polling) trigger, or random access trigger. Note that a random access trigger frame contains a single user information field 420. AP 110 can send a basic trigger frame, a random access trigger frame, or a BSRP trigger frame containing one or more RUs for random access. If the concatenation indication subfield 414 is 1, a subsequent trigger frame follows trigger frame 400. Otherwise, the concatenation indication subfield 414 is 0. The user information field 420 includes an AID12 subfield 422, an RU allocation subfield 424, and an SS allocation subfield 426. The AID12 subfield 422 carries the least significant 12 bits of the AID (Association Identifier) ​​of the STA to which the User Information Field 420 is targeted. A value of 0 in the AID12 subfield 422 indicates that the User Information Field 420 identifies the RU used for random access. The RU allocation subfield 424 indicates the RU allocated to the STA identified by the AID12 subfield 422 for sending a trigger-based PPDU (Physical Layer Protocol Data Unit). In addition to the random access trigger frame, the SS allocation subfield 426 of the User Information Field 420 indicates the spatial flow of the trigger-based PPDU response from the STA identified by the AID12 subfield 422. For the random access trigger frame, the SS allocation subfield 426 of the User Information Field 420 indicates the number of consecutive RUs used for random access, starting from the RU indicated in the RU allocation subfield 422, and each RU has the same size as the RU indicated in the RU allocation subfield 422.

[0062] Back Figure 2 In step 202, the STA determines whether its UL transmission is an initial trigger-based PPDU transmission or a follow-up to a successfully triggered PPDU transmission. If its UL transmission is an initial trigger-based PPDU transmission or a follow-up to a successfully triggered PPDU transmission, the STA sets the OCW value to OCWmin in step 204. Otherwise, the STA continues to check in step 206 whether its UL transmission is a retransmission based on an unsuccessfully triggered PPDU transmission. If its UL transmission is a retransmission based on an unsuccessfully triggered PPDU transmission, the UORA method 200 proceeds to step 210. Otherwise, the UORA method 200 jumps to step 212.

[0063] In step 210, the STA initializes its OBO counter to zero and a random value within the OCW range, and UORA method 200 proceeds to step 214. In step 212, the STA determines whether its OBO counter is equal to zero. If its OBO counter is equal to zero, this means the STA won the contention and selected one of the RUs for random access in the previously received trigger frame, but no trigger-based PPDU was sent in the previously selected RU, which is considered busy, and UORA method 200 proceeds to step 222. If its OBO counter is not equal to zero, this means the STA did not win the contention to access the RU for random access in the previously received trigger frame, and UORA method 200 proceeds to step 214.

[0064] In step 214, the STA checks if its OBO counter is less than the number of RUs used for random access in the received trigger frame. If its OBO counter is less than the number of RUs used for random access in the received trigger frame, the STA reduces its OBO counter to zero in step 216, i.e., it wins the random access contention, and UORA method 200 jumps to step 222. Otherwise, the STA reduces its OBO counter to the number of RUs used for random access in the received trigger frame in step 218. Note that when its OBO counter is the same as the number of RUs used for random access in the received trigger frame, the STA actually reduces its OBO counter to zero. In step 220, the STA determines if its OBO counter is equal to zero. If its OBO counter is equal to zero, it wins the random access contention, and UORA method 200 goes to step 222. Otherwise, UORA method 200 stops.

[0065] In step 222, the STA randomly selects one of the RUs for random access in the received trigger frame. In step 224, the STA checks whether the selected RU is idle as a result of both physical and virtual carrier sensing. If the selected RU is idle, the STA transmits a trigger-based PPDU at the selected RU in step 226. Otherwise, UORA method 200 stops.

[0066] In step 228, the STA determines whether a trigger-based PPDU was successfully sent at the selected RU. If the trigger-based PPDU sent at the selected RU requests an immediate response and the expected response is not received, the transmission is considered unsuccessful, and UORA method 200 proceeds to step 230. Otherwise, the transmission is considered successful, and UORA method 200 stops. If the trigger-based PPDU sent at the selected RU does not request an immediate response, the transmission is also considered successful. In step 230, the STA sets the value of OCW to the minimum of {the sum of twice the current value of OCW and 1} and {the value of OCWmax}, and then UORA method 200 stops.

[0067] Figure 3 The diagram illustrates the use of, for example Figure 2 The illustration shows an example of multi-user frame switching involving STAs in the example UORA method 200. Three STAs (e.g., Figure 1 STA1 122, STA2 124, and STA3 126 in the above scenarios contend for UL transmission using UORA method 200. When trigger frame 310 is received from AP 110, STA1 122, STA2 124, and STA3 126 initiate UORA method 200. Trigger frame 310 contains three RUs for random access (i.e., RU1, RU2, and RU3 with AID set to zero), which are available to all STAs. It is assumed that the UL transmission for each of STA1 122, STA2 124, and STA3 126 is either an initial trigger-based PPDU transmission or a subsequent successful trigger-based PPDU transmission, and that the OBO counters for STA1 122, STA2 124, and STA3 126 are initialized to 11, 5, and 3, respectively. Because the number of RUs used for random access in the received trigger frame 310 is 3, the OBO counters for STA1 122, STA2 124, and STA3 126 become 8, 2, and 0, respectively. Ultimately, STA3 126, whose OBO counter is 0, wins the contention, randomly selects the considered idle RU3, and sends a trigger-based PPDU 320 in RU3SIFS after receiving the trigger frame 310. If STA3 126 receives an acknowledgment frame 330 from AP 110 within a defined time period after sending the trigger-based PPDU 320, the transmission of the trigger-based PPDU 320 is successful. Otherwise, the transmission of the trigger-based PPDU 320 is unsuccessful.

[0068] Although UORA can be scheduled at any time based on AP 110's decision, the most likely use case is when AP 110 is unaware of the existence of unassociated STAs that cannot communicate with AP 110. Specifically, AP 110 may be unaware of the existence of an unassociated 20MHz operational STA. Note that there are currently no rules regarding how AP 110 assigns RUs for random access in the trigger frame. In some cases, AP 110 does not have RUs assigned for random access in the trigger frame available to the 20MHz operational STA. In other words, the RU assigned for random access in the trigger frame is not in the primary 20MHz channel and is used unrestricted by the 20MHz operational STA. In this case, when the trigger frame for random access is received, the 20MHz operational STA cannot reach AP 110 using UORA method 200.

[0069] Next, various embodiments of the apparatus and methods for UORA will be explained in further detail according to this disclosure.

[0070] <First Embodiment>

[0071] According to a first embodiment of this disclosure, a first example UORA method operated by AP 110 involves each Nth trigger frame for random access sent by AP 110 including at least one RU for random access, which is a STA that can be used for 20MHz operation, where N is a positive integer. In other words, each Nth trigger frame for random access contains at least one RU for random access, which is used in the primary 20MHz channel and is unrestricted for 20MHz operation STAs.

[0072] According to a first embodiment of this disclosure, a second example UORA method operated by AP 110 involves AP 110 sending one or more trigger frames for random access during a defined time period (e.g., a beacon interval), each trigger frame including at least one RU for random access, which can be used for STA operation at 20 MHz.

[0073] According to a first embodiment of this disclosure, when a trigger frame for random access is received, a 20MHz operating STA has the opportunity to reach AP 110 using the UORA mechanism.

[0074] Figure 5The illustration shows a first example UORA method 500 operated by a 20MHz operating STA according to a first embodiment of this disclosure. The UORA method 500 begins when the 20MHz operating STA receives a trigger frame for random access from AP 110. In step 502, the 20MHz operating STA determines whether its UL transmission is an initial trigger-based PPDU transmission, a follow-up successful trigger-based PPDU transmission, or a follow-up unsuccessful trigger-based PPDU transmission with no further retransmission attempts. If its UL transmission is an initial trigger-based PPDU transmission, a follow-up successful trigger-based PPDU transmission, or a follow-up unsuccessful trigger-based PPDU transmission with no further retransmission attempts, then in step 504, the 20MHz operating STA sets the OCW value to OCWmin and sets the RAR (Random Access Retry) counter to zero, where the RAR counter is an internal counter maintained by the STA for tracking retransmission attempts of failed trigger-based PPDU transmissions. Otherwise, in step 506, the 20MHz operating STA continues to check whether its UL transmission is a retransmission of an unsuccessful trigger-based PPDU transmission. If its UL transmission is based on a retransmission of an unsuccessfully triggered PPDU transmission, then UORA method 500 proceeds to step 510. Otherwise, UORA method 500 jumps to step 512.

[0075] In step 510, the 20MHz operating STA initializes its OBO counter to zero and a random value within the OCW range, and UORA method 500 proceeds to step 514. In step 512, the 20MHz operating STA determines whether its OBO counter is equal to zero. If its OBO counter is equal to zero, this means the 20MHz operating STA won the contention and selected one of the RUs for random access in the previously received trigger frame, but no trigger-based PPDU was transmitted in the previously selected RU because one or more 20MHz channels containing the previously selected RU were considered busy, and UORA method 500 proceeds to step 521. If its OBO counter is not equal to zero, this means the 20MHz operating STA did not win the contention to access the RU for random access in the previously received trigger frame, and UORA method 500 proceeds to step 514.

[0076] In step 514, the 20MHz operating STA checks whether its OBO counter is not greater than the number of RUs used for random access in the received trigger frame. If its OBO counter is not greater than the number of RUs used for random access in the received trigger frame, then in step 516, the 20MHz operating STA reduces its OBO counter to zero, meaning it wins the random access contention, and UORA method 500 jumps to step 521. Otherwise, in step 518, the 20MHz operating STA subtracts the number of RUs used for random access in the received trigger frame from its OBO counter, and then UORA method 500 stops. Note that steps 514 to 518 of UORA method 500 perform random access contention in a more efficient manner than steps 214 to 220 of UORA method 200 because UORA method 500 requires one less step than UORA method 200.

[0077] In step 521, the 20MHz operating STA determines whether at least one RU for random access is available for the 20MHz operating STA in the received trigger frames. If each trigger frame for random access contains at least one RU for random access available for the 20MHz operating STA, step 521 can be skipped. If at least one RU for random access is available for the 20MHz operating STA in the received trigger frames, the UORA method 500 proceeds to step 522. Otherwise, the UORA method 500 stops.

[0078] In step 522, the 20MHz operating STA randomly selects one of the RUs (Remote Access Units) available for random access from the received trigger frames. In step 524, the 20MHz operating STA checks whether each of the one or more 20MHz channels including the selected RU is idle as a result of both physical and virtual carrier sensing. If each of the one or more 20MHz channels including the selected RU is idle, then in step 526, the 20MHz operating STA transmits a trigger-based PPDU at the selected RU. Otherwise, UORA method 500 stops. Note that step 524 of UORA method 500 differs from step 224 of UORA method 200 because the 20MHz operating STA's check of the CCA (Clear Channel Assessment) of one or more 20MHz channels is more practical than the RU.

[0079] In step 528, the 20MHz operation STA determines whether a trigger-based PPDU was successfully transmitted at the selected RU. If the trigger-based PPDU transmitted at the selected RU requests an immediate response and the expected response is not received, the transmission is considered unsuccessful, and the UORA method 500 proceeds to step 530. Otherwise, the transmission is considered successful, and the UORA method 500 stops. If the trigger-based PPDU transmitted at the selected RU does not request an immediate response, the transmission is also considered successful. In step 530, the 20MHz operation STA increments the RAR counter by 1 and sets the OCW value to the minimum current value of OCW multiplied by 2 plus 1 and OCWmax. In step 532, the 20MHz operation STA determines whether the RAR counter is greater than a threshold called RARtryLimit, which indicates the maximum number of random access retransmission attempts. If the RAR counter is not greater than the threshold RARtryLimit, the UORA method 500 stops. Otherwise, the 20MHz operation STA determines in step 534 that there are no more retransmission attempts, and then the UORA method 500 stops.

[0080] Note that the first example UORA method 500 differs from the example UORA method 200 in that the former requires a 20MHz operating STA to maintain the RAR counter. If its UL transmission is followed by a transmission of a PPDU based on an unsuccessful trigger without further retransmission attempts, this allows the 20MHz operating STA to reset the OCW to OCWmin. This increases the probability of winning random access contention and successfully transmitting a trigger-based PPDU in a randomly selected RU when a trigger frame for random access is received after several failed consecutive retransmission attempts.

[0081] Figure 6 The illustration depicts an example UORA method 600 operated by a non-20MHz operating STA according to a first embodiment of this disclosure. UORA method 600 begins when a non-20MHz operating STA receives a trigger frame for random access from AP 110. Steps 602 to 618 are respectively related to... Figure 5 Steps 502 to 518 in the UORA method 500 shown are the same.

[0082] In step 622, the non-20MHz operating STA randomly selects one of the RUs used for random access in the received trigger frame. Steps 624 to 634 are respectively related to... Figure 5 Steps 524 to 534 in the UORA method 500 shown are the same.

[0083] Note that, similar to Figure 5The difference between Example UORA Method 500, Example UORA Method 600, and Example UORA Method 200 is that the former requires a non-20MHz operating STA to maintain the RAR counter. This allows the non-20MHz operating STA to reset the OCW to OCWmin if its UL transmission is followed by an unsuccessful trigger-based PPDU transmission with no further retransmission attempts. This increases the probability of winning random access contention and successfully transmitting a trigger-based PPDU in a randomly selected RU when a trigger frame for random access is received after several failed consecutive retransmission attempts.

[0084] Figure 7 The illustration depicts a first example of multi-user frame switching related to UORA according to a first embodiment of this disclosure. STA1 and STA2 are non-20MHz operating STAs using UORA method 600 and contain content for UL transmission, while STA3 is a 20MHz operating STA using UORA method 500 and contains content for UL transmission. When a trigger frame 750 containing three RUs (i.e., RU1, RU2, and RU3 with AID set to zero) for random access is received from an AP that is not available for a 20MHz operating STA, STA1 and STA2 initiate UORA method 600, and STA3 initiates UORA method 500. Assuming that the UL transmission for each of STA1, STA2, and STA3 is either an initial trigger-based PPDU transmission or a follow-up trigger-based PPDU transmission, the OBO counters for STA1, STA2, and STA3 are initialized to 11, 5, and 3, respectively. Because the number of RUs for random access in the received trigger frame 750 is 3, the OBO counters for STA1, STA2, and STA3 become 8, 2, and 0, respectively. Ultimately, STA3, whose OBO counter is 0, wins the random access contention and randomly selects RU3 as the STA available for operation in the 20MHz range. If each of the one or more 20MHz channels including RU3 is considered idle, STA3 transmits a trigger-based PPDU 760 at RU3 SIFS after receiving trigger frame 750. If STA3 receives an acknowledgment frame 770 from AP within a defined time period after transmitting trigger-based PPDU 760, the transmission of trigger-based PPDU 760 is successful. Otherwise, the transmission of trigger-based PPDU 760 is unsuccessful.

[0085] Figure 8 The illustration shows a second example UORA method 800 operated by a 20MHz operating STA according to a first embodiment of this disclosure. UORA method 800 begins when the 20MHz operating STA receives a trigger frame for random access from the AP.

[0086] In step 801, the 20MHz operating STA determines whether at least one RU for random access is available for the 20MHz operating STA in the received trigger frames. If each trigger frame for random access contains at least one RU for random access available for the 20MHz operating STA, step 801 can be skipped. If at least one RU for random access is available for the 20MHz operating STA in the received trigger frames, the UORA method 800 proceeds to step 802. Otherwise, the UORA method 800 stops.

[0087] Steps 802 to 812 are respectively with Figure 5 Steps 502 to 512 in the UORA method 500 shown are the same.

[0088] In step 814, the 20MHz operating STA checks if its OBO counter is not greater than the number of RUs available for random access in the received trigger frame. If its OBO counter is not greater than the number of RUs available for random access in the received trigger frame, then in step 816, the 20MHz operating STA reduces its OBO counter to zero, meaning it wins the random access contention. UORA method 800 then jumps to step 822. Otherwise, in step 818, the 20MHz operating STA subtracts the number of RUs available for random access in the received trigger frame from its OBO counter, and then UORA method 800 stops.

[0089] Notice, Figure 8 The second example of UORA method 800 and Figure 5 The difference between the first example UORA method 500 and the previous method is that, for the former method, the 20MHz operating STA only considers the RUs available for random access during random access contention. Therefore, the former method allows the 20MHz operating STA to reduce its OBO counter more slowly, thus reducing its chance of winning random access contention.

[0090] Figure 8 Steps 822 to 834 in the text are respectively related to Figure 5 The UORA method 500 shown Figure 5 Steps 522 to 534 are the same.

[0091] Figure 9 The illustration depicts a second example of multi-user frame switching associated with UORA according to a first embodiment of this disclosure. STA1 and STA2 are using... Figure 8 The UORA method 600 non-20MHz operation STA and content for UL transmission, while STA3 is used Figure 8 The content of the 20MHz operating STA and UL transmission in UORA method 800 is as follows. When a trigger frame 950 containing three RUs (i.e., RU1, RU2, and RU3 with AID set to zero) for random access is received from an AP that is not available for the 20MHz operating STA, STA1 and STA2 initiate UORA method 600, and STA3 initiates UORA method 800. Assume that the UL transmission for each of STA1, STA2, and STA3 is either an initial trigger-based PPDU transmission or a follow-up trigger-based PPDU transmission, and the OBO counters of STA1, STA2, and STA3 are initialized to 11, 5, and 3, respectively. Because the number of RUs for random access in the received trigger frame 950 is 3, and the number of RUs for random access available for the 20MHz operating STA in the received trigger frame 950 is 2, the OBO counters of STA1, STA2, and STA3 become 8, 2, and 1, respectively. Ultimately, no STA wins the random access contention.

[0092] Figure 10 An example format of a trigger frame 1000 according to a first embodiment of the present disclosure is illustrated. The trigger frame 1000 includes a common information field 1010 and one or more user information fields 1020. The common information field 1010 includes a trigger type subfield 1012, a cascading indication subfield 1014, and a trigger-related common information subfield 1016. The trigger type subfield 1012 and the cascading indication subfield 1014 are identical to their respective corresponding portions 412 and 414 in the trigger frame 400, as shown in FIG400. The trigger-related common information subfield 1016 also includes a priority subfield 1032 indicating the priority of a 20MHz operating STA. For example,

[0093] - Priority subfield 1032 is set to 0 to indicate that a 20MHz operating STA has a lower priority than a non-20MHz operating STA;

[0094] - Priority subfield 1032 is set to 1 to indicate that a 20MHz operating STA has a higher priority than a non-20MHz operating STA;

[0095] - The priority subfield 1032 is set to 2 to indicate that a 20MHz operating STA has the same priority as a non-20MHz operating STA.

[0096] Alternatively, priority signaling can be broadcast in beacon frames or probe response frames. Figure 11 The illustration shows an example format of a UORA parameter element 1100 included in a beacon frame or probe response frame according to a first embodiment of the present disclosure. The UORA element 1100 includes a priority field 1110, which is configured to... Figure 10 The priority subfield 1032 indicates the priority of the 20MHz operating STA in the same way.

[0097] According to a first embodiment of this disclosure, whether a 20MHz operating STA uses the first example UORA method 500 or the second example UORA method 800 depends on the priority signaling broadcast in the UORA parameter elements included in the trigger frame for random access or in the beacon frame or probe response frame. For example, if the 20MHz operating STA has a lower priority than a non-20MHz operating STA, then the second UORA method 800 is used by the 20MHz operating STA. Otherwise, the first example UORA method 500 is used by the 20MHz operating STA. Therefore, the 20MHz operating STA can optimize its UORA operation according to its priority.

[0098] According to a first embodiment of this disclosure, in a UORA parameter element included in a trigger frame for random access or in a beacon frame or probe response frame, an AP can broadcast multiple pairs of OCWmin and OCWmax values, each pair being assigned to a STA with a specific priority. For example, the AP can broadcast two pairs of OCWmin and OCWmax values. A first pair of OCWmin and OCWmax values ​​is assigned to a STA with a higher priority, and a second pair is assigned to a STA with a lower priority. If a 20MHz operating STA has a higher priority than a non-20MHz operating STA, the first pair of OCWmin and OCWmax values ​​is assigned to the 20MHz operating STA, and the second pair is assigned to the non-20MHz operating STA, and vice versa. STAs can know the values ​​of their OCWmin and OCWmax based on the priority indicated in the UORA parameter element included in the trigger frame for random access or in the beacon frame or probe response frame. Basically, STAs with higher priority have smaller OCWmin and OCWmax values ​​than STAs with lower priority. Therefore, STAs with higher priority may have a higher probability of winning random access contention in UORA method 500, UORA method 600, or UORA method 800.

[0099] Alternatively, in the UORA parameter elements included in the trigger frame for random access or in the beacon frame or probe response frame, the AP can broadcast a single value pair of OCWmin and OCWmax, which is assigned to STAs with a specific priority, for example, as... Figure 10 The OCWmin subfield 1034 and OCWmax subfield 1036 in the trigger-related common information subfield 1016 of the trigger frame 1000 shown, or as... Figure 11The OCWmin field 1112 and OCWmax field 1114 in the UORA parameter element 1100 are shown. The values ​​of OCWmin and OCWmax for a STA with a different priority can be derived from the broadcast values ​​of OCWmin and OCWmax. For example, an AP can broadcast a single pair of OCWmin and OCWmax values ​​for a STA with a higher priority. If a 20MHz operating STA has a higher priority than a non-20MHz operating STA, the broadcast pair of OCWmin and OCWmax values ​​is assigned to the 20MHz operating STA, and the OCWmin and OCWmax value pair for the non-20MHz operating STA is equal to the OCWmin and OCWmax value pair for the 20MHz operating STA plus a defined positive integer.

[0100] <Second Embodiment>

[0101] According to a second embodiment of this disclosure, a first example UORA method operated by an AP includes at least one random access RU (RU) available for random access from a 20MHz operating STA, where N is a positive integer, in each Nth trigger frame sent by the AP. The trigger frame may include random access RUs available for 20MHz operating STAs, and may also include at least one random access RU not available for 20MHz operating STAs. In this trigger frame, the at least one random access RU available for 20MHz operating STAs is restricted to use for non-20MHz operating STAs. Furthermore, the number of random access RUs available for non-20MHz operating STAs is restricted to be the same as the number of random access RUs not available for 20MHz operating STAs.

[0102] According to a second embodiment of this disclosure, a second example UORA method operated by an AP involves the AP transmitting one or more trigger frames for random access during a defined time period (e.g., a beacon interval). Each trigger frame includes at least one RU (Random Access RU) available for random access from a 20MHz operating STA. In a trigger frame that includes at least one RU available for random access from a 20MHz operating STA and at least one RU not available for random access from a 20MHz operating STA, the at least one RU available for random access from a 20MHz operating STA is restricted to use for non-20MHz operating STAs, and the number of RUs available for random access from non-20MHz operating STAs is restricted to be the same as the number of RUs not available for random access from a 20MHz operating STA.

[0103] According to a second embodiment of this disclosure, when a trigger frame for random access is received, a 20MHz operating STA has the opportunity to reach the AP using the UORA mechanism. Furthermore, after winning the random access contention, the probability of successful transmission in the selected RU for a 20MHz operating STA can be similar to the probability for a non-20MHz operating STA.

[0104] Figure 12 The illustration shows a first example UORA method 1200 operated by a non-20MHz STA according to a second embodiment of this disclosure. The UORA method operated by a 20MHz STA is also shown. Figure 5 The UORA method 500 shown or as... Figure 8 The UORA method 800 shown is the same. When a non-20MHz operating STA receives a trigger frame for random access from the AP, Figure 12 The UORA method starts at 1200.

[0105] Steps 1202 to 1218 are respectively with Figure 5 Steps 502 to 518 in the UORA method 500 shown are the same.

[0106] In step 1222, the non-20MHz operating STA randomly selects one of the RUs for random access that can be used by the non-20MHz operating STA in the received trigger frame.

[0107] Steps 1224 to 1234 are respectively with Figure 5 Steps 524 to 534 in the UORA method 500 shown are the same.

[0108] Figure 13The illustration depicts a first example of multi-user frame switching related to UORA according to a second embodiment of this disclosure. STA1 and STA2 are non-20MHz operating STAs using UORA method 1200 and contain content for UL transmission, while STA3 is a 20MHz operating STA using UORA method 500 and contains content for UL transmission. When an AP receives a trigger frame 1350 containing three RUs (i.e., RU1, RU2, and RU3 with AID set to zero) for random access from an AP that is not available for a 20MHz operating STA and RU3 is not available for a non-20MHz operating STA, STA1 and STA2 initiate UORA method 1200, and STA3 initiates UORA method 500. It is assumed that the UL transmission of each of STA1, STA2, and STA3 is an initial trigger-based PPDU transmission or a follow-up successful trigger-based PPDU transmission, and the OBO counters of STA1, STA2, and STA3 are initialized to 3, 5, and 10, respectively. Because the number of RUs used for random access in the received trigger frame 1350 is 3, the OBO counters of STA1, STA2, and STA3 become 0, 2, and 8, respectively. Ultimately, STA1, whose OBO counter is 0, wins the random access contention and randomly selects RU2, which can be used by a non-20MHz operating STA. If each of one or more 20MHz channels, including RU2, is considered idle, STA1 transmits a trigger-based PPDU 1360 at RU2SIFS after receiving trigger frame 1350. If STA1 receives an acknowledgment frame 1370 from the AP within a defined time period after transmitting trigger-based PPDU 1360, the transmission of trigger-based PPDU 1360 is successful. Otherwise, the transmission of trigger-based PPDU 1360 is unsuccessful.

[0109] Figure 14 The illustration shows a second example UORA method 1400 operated by a non-20MHz operating STA according to a second embodiment of the present disclosure. UORA method 1400 begins when a non-20MHz operating STA receives a trigger frame for random access from an AP.

[0110] Figure 14 Steps 1402 to 1412 in the above are respectively with Figure 5 Steps 502 to 512 in the UORA method 500 shown are the same.

[0111] In step 1414, the non-20MHz operating STA checks whether its OBO counter is not greater than the number of RUs available for random access in the received trigger frame. If its OBO counter is not greater than the number of RUs available for random access in the received trigger frame, the non-20MHz operating STA reduces its OBO counter to zero in step 1416, meaning it wins the random access contention, and UORA method 1400 jumps to step 1422. Otherwise, the non-20MHz operating STA subtracts the number of RUs available for random access from its OBO counter at step 1418, and then UORA method 1400 stops.

[0112] Notice, Figure 14 The second example of UORA method 1400 and Figure 12 The difference between the first example UORA method 1200 and the previous method is that, for the former method, non-20MHz operating STAs only consider the RUs available for random access during random access contention. Therefore, the former method allows non-20MHz operating STAs to reduce their OBO counters more slowly, thus reducing their chances of winning random access contention.

[0113] In step 1422, the non-20MHz operating STA randomly selects one of the RUs for random access that can be used by the non-20MHz operating STA in the received trigger frame.

[0114] Steps 1424 to 1434 are respectively with Figure 5 Steps 524 to 534 in the UORA method 500 shown are the same.

[0115] Figure 15 The illustration depicts a second example of multi-user frame switching associated with UORA according to a second embodiment of this disclosure. STA1 and STA2 are using... Figure 14 The UORA method 1400 non-20MHz operation STA and content for UL transmission, while STA3 is used Figure 8The content of the 20MHz operating STA and UL transmission in UORA method 800 is as follows. When an AP that is not available for a 20MHz operating STA and RU3 is not available for a non-20MHz operating STA receives a trigger frame 1550 containing three RUs (i.e., RU1, RU2, and RU3 with AID set to zero) for random access, STA1 and STA2 initiate UORA method 1400, and STA3 initiates UORA method 800. Assume that the UL transmission of each of STA1, STA2, and STA3 is an initial trigger-based PPDU transmission or a follow-up trigger-based PPDU transmission, and the OBO counters for STA1, STA2, and STA3 are initialized to 3, 5, and 11, respectively. Because the number of RUs for random access in the received trigger frame 1550 is 3, the OBO counters for STA1, STA2, and STA3 become 1, 3, and 9, respectively. Ultimately, no STA wins the random access contention.

[0116] Figure 16 An example format of a trigger frame 1600 according to a second embodiment of the present disclosure is illustrated. The trigger frame 1600 includes a public information field 1610 and one or more user information fields 1620. The user information field 1620 includes an AID12 subfield 1622, an RU allocation subfield 1624, an SS allocation subfield 1626, and a restriction indication subfield 1628. The AID12 subfield 1622, RU allocation field 1624, and SS allocation field 1626 are identical to their respective corresponding portions 422, 424, and 426 in the trigger frame 400, as shown below. Figure 4 As shown. The restriction indication subfield 1628 indicates whether the RU used for random access is restricted to use with a STA operating outside of 20MHz. For example,

[0117] - Limitation indicator subfield 1628 is set to 0 to indicate that the RU is not limited to use with STAs that are not operating at 20MHz, and

[0118] - Set the restriction indicator subfield 1628 to 1 to indicate that the RU is restricted to use for non-20MHz operating STAs.

[0119] <Power Saving Using UL OFDMA-Based Random Access>

[0120] TWT (Target Wake-Up Time) is an 802.11 feature that allows an AP to define a specific time or set of times for STAs to access the medium. STAs and APs exchange information including the expected duration of activity to allow the AP to control contention and overlap between competing STAs. TWT can be used to reduce network energy consumption because STAs using it can enter a sleep state until their TWT arrives.

[0121] Figure 17 The illustration shows an example format of TWT element 1700. TWT element 1700 includes a control field 1710, a request type field 1720, a target wake-up time field 1730, and a TWT wake-up interval tail number field 1740. Control field 1710 includes a broadcast subfield 1712, which indicates whether the TWT SP (Service Term) defined by TWT element 1700 is a broadcast TWT SP. Broadcast subfield 1712 is 1 to indicate that the TWT SP defined by TWT element 1700 is a broadcast TWT SP. Otherwise, broadcast subfield 1712 is 0. Request type field 1720 includes a trigger subfield 1722, a TWT stream identifier subfield 1724, and a TWT wake-up interval index subfield 1726. Trigger subfield 1722 indicates whether the TWT SP defined by TWT element 1700 includes a trigger frame. Trigger subfield 1722 is set to 1 to indicate that TWT is triggered, that is, at least one trigger frame is sent during the TWT SP. Otherwise, the trigger subfield 1722 is set to 0. For broadcast TWT SPs, the TWT Stream Identifier subfield 1724 contains a recommended value indicating the type of frames sent by the scheduled STA during the broadcast TWT SP. The TWT Stream Identifier subfield 1724 is set to 0 to indicate that there are no constraints on the frames sent during the broadcast TWT SP, and that trigger frames sent during the broadcast TWT SP may contain zero or more RUs for random access. The TWT Stream Identifier subfield 1724 is set to 1 to indicate i) there are no constraints on the frames sent by the scheduled STA during the broadcast TWT SP, ii) it is recommended that the frames sent by the scheduled STA during the broadcast TWT SP be limited to certain types of frames (e.g., frames sent as part of a probe feedback exchange); and iii) trigger frames sent by the AP during the broadcast TWT SP will not contain RUs for random access. The TWT Stream Identifier subfield 1724 is set to 2 to indicate i) there are no constraints on frames sent by the scheduled STA during the broadcast TWT SP, ii) it is recommended that frames sent by the scheduled STA during the broadcast TWT SP be limited to certain types of frames (e.g., frames sent as part of a probe feedback exchange); and iii) trigger frames sent by the AP during the broadcast TWT SP will contain at least one RU for random access. The TWT wake-up time of the scheduled STA is determined by the Target Wake-up Time field 1730, while the TWT Wake-up Interval of the scheduled STA is determined by the TWT Wake-up Interval Tail field 1740 and the TWT Wake-up Interval Index subfield 1726.

[0122] According to the first example power-saving mechanism with UORA, a STA receiving a beacon frame or management frame containing TWT element 1700 can enter a sleep state until the start of a TWT SP defined by TWT element 1700. TWT element 1700 includes a broadcast subfield 1712 set to 1 and a TWT stream identifier subfield 1724 set to 2.

[0123] According to the second example power-saving mechanism with UORA, if random access allocation occurs within a trigger frame sequence within a trigger-enabled TWT SP, all trigger frames in the sequence should set the cascading indicator field to 1, except for the last trigger frame in the sequence, whose cascading indicator field should be set to 0. The STA can use the value indicated in the cascading indicator field of the trigger frame to enter a sleep state. If its OBO counter decreases to a non-zero value during a random access process in a trigger frame with the cascading indicator field set to 1, it can immediately enter a sleep state. If its OBO counter decreases to a non-zero value during a random access process in a trigger frame with the cascading indicator field set, it can remain awake for random access in the cascading trigger frame.

[0124] <Third Embodiment>

[0125] Figure 18 An example format of a TWT element 1800 according to a third embodiment of this disclosure is illustrated. The TWT element 1800 includes a control field 1810, a request type field 1820, a target wake-up time field 1830, and a TWT wake-up interval tail number field 1840. The control field 1810 includes a broadcast subfield 1812. The request type field 1820 includes a trigger subfield 1822, a TWT stream identifier subfield 1824, and a TWT wake-up interval index subfield 1826. The request type field 1820, the target wake-up time field 1830, and the TWT wake-up interval tail number field 1840 are identical to their corresponding portions 1720, 1730, and 1740. The control field 1810 differs from its corresponding portion 1710 in that it includes an additional RA (Random Access) restriction subfield 1818. The RA restriction subfield 1818 indicates whether at least one RU for random access in a trigger frame transmitted within a broadcast TWT SP defined by the TWT element 1800 is available for a 20MHz operating STA. The RA restriction subfield 1818 is set to 0 to indicate that at least one RU for random access in the trigger frame transmitted within the broadcast TWT SP is available for a 20MHz operating STA. Otherwise, the RA restriction subfield 1818 is set to 1.

[0126] According to a third embodiment of this disclosure, when a 20MHz operating STA receives a beacon frame or management frame containing TWT element 1800, it can enter a sleep state until the start of a TWT SP defined by TWT element 1800. The TWT element 1800 includes a broadcast subfield 1812 set to 1, a trigger subfield 1822 set to 1, an RA restriction field 1818 set to 0, and a TWT stream identifier subfield 1824 set to 0 or 2. Furthermore, the trigger-based TWT SP defined by TWT element 1800 includes one or more trigger frames for random access, wherein at least one RU for random access can be used by the 20MHz operating STA. When a 20MHz operating STA receives a beacon frame or management frame containing TWT element 1800 with broadcast subfield 1812 set to 1, trigger subfield 1822 set to 1, and RA restriction subfield 1818 set to 1, i.e., the trigger-based TWT SP defined by TWT element 1800 contains one or more trigger frames for random access, where no RU for random access is available to the 20MHz operating STA, it can enter a sleep state at least until the end of the TWT SP defined by TWT element 1800. Therefore, according to the third embodiment of this disclosure, using the RA restriction subfield 1818 in TWT element 1800, the 20MHz operating STA may be able to save more power compared to the first example power-saving mechanism with UORA.

[0127] According to a third embodiment of this disclosure, a 20MHz operating STA or a non-20MHz operating STA can utilize the values ​​of the signaling fields in TWT element 1800 to save more power in various ways. For the first example, when a non-20MHz operating STA receives a beacon frame or management frame containing TWT element 1800 with broadcast subfield 1812 set to 1, trigger subfield 1822 set to 1, and TWT stream identifier subfield 1824 set to 0 or 2, i.e., when the trigger-based TWT SP defined by TWT element 1800 contains zero or more RUs for random access, it can enter a dormant state until the start of the TWT SP defined by TWT element 1800. For the second example, when a non-20MHz operating STA or a 20MHz operating STA receives a beacon frame or management frame containing TWT element 1800 and the broadcast subfield 1812 is set to 1, the trigger subfield 1822 is set to 1, and the TWT stream identifier subfield 1824 is set to 1, i.e., the trigger-based TWT SP defined by TWT element 1800 does not contain an RU for random access, it can enter a sleep state at least until the end of the TWT SP defined by TWT element 1800. For the third example, when a non-20MHz operating STA or a 20MHz operating STA receives a beacon frame or management frame containing TWT element 1800, where the broadcast subfield 1812 is set to 1 and the trigger subfield 1822 is set to 0, i.e., the TWT SP defined by TWT element 1800 does not contain any trigger frames, it can enter a sleep state at least until the end of the TWT SP defined by TWT element 1800.

[0128] <Fourth Embodiment>

[0129] According to the fourth embodiment of this disclosure, as Figure 10 The common information field 1010 of the shown trigger frame 1000 may include a subsequent TF-R indication subfield 1018. This subsequent TF-R indication subfield 1018 contains information indicating whether any subsequent trigger frame includes at least one RU for random access available to a 20MHz operating STA. The subsequent TF-R indication subfield 1018 is set to 1 to indicate that the subsequent trigger frame includes at least one RU for random access available to a 20MHz operating STA; otherwise, the subsequent TF-R indication subfield 1018 is set to 0.

[0130] According to the fourth embodiment of this disclosure, if random access allocation is performed in the sequence of trigger frames within a trigger-enabled TWT SP, all trigger frames in the sequence should have their concatenation indicator field set to 1, except for the last trigger frame in the sequence, whose concatenation indicator field should be set to 0.

[0131] According to a fourth embodiment of this disclosure, if random access allocation is performed in a sequence of trigger frames within a trigger-enabled TWT SP, then if subsequent trigger frames in the sequence do not contain any RUs for random access available for 20MHz operating STAs, the trigger frames in the sequence should set the subsequent TF-R indicator subfield to 0.

[0132] According to a fourth embodiment of this disclosure, a 20MHz operating STA or a non-20MHz operating STA can utilize the value indicated in the cascading indication field of a trigger frame for power-saving purposes in various ways. For a first example, if the OBO counter decreases to a non-zero value using a UORA method (e.g., UORA method 500, UORA method 800, UORA method 600, UORA method 1200, or UORA method 1400) in a trigger frame with the cascading indication field set to 0, or if the OBO counter decreases to zero and each of one or more 20MHz channels including the selected RU in a trigger frame with the cascading indication field set to 0 is considered busy using a UORA method (e.g., UORA method 500, UORA method 800, UORA method 600, UORA method 1200, or UORA method 1400), i.e., when there are no more cascading trigger frames, the 20MHz operating STA or the non-20MHz operating STA can immediately enter a sleep state. If the OBO counter decreases to a non-zero value using a UORA method (e.g., UORA method 600, UORA method 1200, or UORA method 1400) in a trigger frame with the cascading indication field set to 1, or if the OBO counter decreases to zero, then in a trigger frame with the cascading indication field, and in a trigger frame with the cascading indication field set to 1, each of one or more 20MHz channels of the selected RU is considered busy using a UORA method (e.g., UORA method 500, UORA method 800, UORA method 600, UORA method 1200, or UORA method 1400), i.e., there is at least one more cascading trigger frame, the non-20MHz operating STA can remain awake for random access in the cascading trigger frame.

[0133] According to a fourth embodiment of the present disclosure, a 20MHz operating STA can enter the sleep state using the values indicated in the cascade indication field in the trigger frame and the values indicated in the subsequent TF-R indication subfield. For example, if the OBO counter is reduced to a non-zero value using the UORA method (e.g., UORA method 500 or UORA method 800) in a trigger frame with the cascade indication field set to 1 and the subsequent TF-R indication field set to 0, there is no RU available for random access in the cascade trigger frame for the 20MHz operating STA. And the 20MHz operating STA can immediately enter the sleep state. For another example, if the OBO counter is reduced to zero but each of one or more 20MHz channels including the selected RU in a trigger frame with the cascade indication field set to 1 and the subsequent TF-R indication field set to 0 is considered busy using the UORA method (e.g., UORA method 500 or UORA method 800), that is, there is no RU available for random access in the cascade trigger frame for the 20MHz operating STA. And the 20MHz operating STA can immediately enter the sleep state.

[0134] Therefore, according to a fourth embodiment of the present disclosure, using the subsequent TF-R indication subfield in the trigger frame, compared with the second example power-saving mechanism with UORA, the 20MHz operating STA may be able to save more power. If the OBO counter is reduced to a non-zero value using the UORA method (e.g., UORA method 500 or UORA method 800) in a trigger frame with the cascade indication field set to 1 and the subsequent TF-R indication field set to 1, at least one RU for random access in the cascade trigger frame is available for the 20MHz operating STA. And the 20MHz operating STA can stay awake in the cascade trigger frame for random access. Or, if the OBO counter is reduced to zero but each of one or more 20MHz channels including the selected RU in a trigger frame with the cascade indication field set to 1 and the subsequent TF-R indication field set to 1 is considered busy using the UORA method (e.g., UORA method 500 or UORA method 8), that is, at least one RU for random access in the cascade trigger frame is available for the 20MHz operating STA. And the 20MHz operating STA can stay awake in the cascade trigger frame for random access.

[0135] <Configuration of STA>

[0136] Figure 19A is a simple block diagram of an example STA1900A, which may be Figure 1Any STA. STA1900A includes a receive signal processing circuit 1904 and a receive unit 1906. Receiver unit 1906 receives multiple signals transmitted by the AP. Each received signal may carry a trigger frame for random access, a beacon frame including a TWT element, or a management frame including a TWT element. The trigger frame is configured according to a first, second, and / or fourth embodiment of this disclosure. The TWT element is configured according to a third embodiment of this disclosure. The receive signal processing circuit 1904 processes the received signals.

[0137] Figure 19B This is a detailed block diagram of the example STA1900B, which can be... Figure 1 Any STA. STA 1900B includes a CPU (Central Processing Unit) 1930 coupled to memory 1920, auxiliary memory 1940, and one or more wireless communication interfaces 1950. Auxiliary memory 1940 may be a non-volatile computer-readable storage medium used to permanently store relevant instruction code and data, etc. At startup, CPU 1930 can copy instruction code and related data to volatile memory 1920 for execution. Instruction code may include the operating system, user applications, device drivers, and executable code required for the operation of STA 1900B. STA 1900B may also include a power supply 1910, such as a lithium-ion battery or a button cell battery. Wireless communication interface 1950 may include an interface for cellular communication or an interface for short-range communication protocols such as Zigbee, or it may be a WLAN interface. Wireless communication interface 1950 may also include a MAC (Media Access Control) module 1980 and a PHY (Physical Layer) module 1960. MAC module 1980 may include UORA circuitry 1982, which is responsible for operating the UORA method according to the first or second embodiment of this disclosure. MAC module 1980 may also include power-saving circuitry 1984, which is responsible for configuring STA 1900B to enter a sleep state according to the third and fourth embodiments of this disclosure. MAC module 1980 may also include message processing circuitry 1986, which is responsible for generating MAC frames to be transmitted and processing received MAC frames (e.g., trigger frames, beacon frames, etc.). PHY module 1960 is responsible for converting data from MAC module 1980 into transmit / receive signals and converting data from transmit / receive signals. Wireless communication interface 1950 may also be coupled to one or more antennas 1970 via PHY module 1960, which are responsible for the actual transmission / reception of wireless communication signals on / from the wireless medium.

[0138] exist Figure 19B For clarity, the STA 1900B may include many other components not shown. Only those components most relevant to this disclosure are illustrated.

[0139] <Access Point Configuration>

[0140] Figure 20A This is a simplified block diagram of the example AP 2000A, which can be... Figure 1 AP 110 in the present invention. AP 2000A includes a transmission signal generation circuit 2004 and a transmitting unit 2006. The transmission signal generation circuit 2004 generates multiple transmission signals. Each transmission signal may carry a trigger frame for random access, a beacon frame including a TWT element, or a management frame including a TWT element. The trigger frame is configured according to a first, second, and / or fourth embodiment of the present disclosure. The TWT element is configured according to a third embodiment of the present disclosure. The transmitting unit 2006 transmits the generated transmission signals.

[0141] Figure 20B This is a detailed block diagram of the example AP 2000B, which can be... Figure 1 The AP 110 is an example of an AP 2000B. The AP 2000B includes a CPU 2030 coupled to a memory 2020, an auxiliary memory 2040, one or more wireless communication interfaces 2050, and other wired communication interfaces 2080. The auxiliary memory 2040 can be a non-volatile computer-readable storage medium used to permanently store relevant instruction code and data. At startup, the CPU 2030 can copy instruction code and related data to the volatile memory 2020 for execution. The instruction code can include the operating system, user applications, device drivers, and executable code required for the operation of the AP 2000B. The size of the instruction code, and therefore the storage capacity of the auxiliary memory 2040 and the memory 2020, can be significantly larger than the storage capacity of the STA1900B.

[0142] The AP 2000B may also include a power supply 2010, which in most cases can be a power source, but in some cases it may be a high-capacity battery, such as a car battery. The wired communication interface 2090 may be an Ethernet interface, a powerline interface, or a telephone line interface, etc. The wireless communication interface 2050 may include an interface for cellular communication, an interface for short-range communication protocols such as Zigbee, or it may be a WLAN interface.

[0143] The wireless communication interface 2050 may further include a MAC module 2080 and a PHY module 2060. The MAC module 2080 may include an RU allocation and scheduling circuit 2082, which is responsible for allocating RUs for DL ​​or UL OFDMA transmissions. Specifically, according to a first or second embodiment of this disclosure, the RU allocation and scheduling circuit 2082 allocates RUs for random access in a trigger frame. The MAC module 2080 may further include a message processing circuit 2084, which is responsible for generating MAC messages to be sent and processing received MAC messages. Specifically, according to a first, second, third, or fourth embodiment of the present invention, the message processing circuit 2084 generates a trigger frame, a TWT element included in a beacon frame or management frame, or a UORA parameter element included in a beacon frame or probe response frame.

[0144] PHY module 2060 is responsible for converting data from MAC module 2080 into transmit / receive signals and converting data from transmit / receive signals. Wireless communication interface 2050 can also be coupled to one or more antennas 2070 via PHY module 2060, and antenna 2070 is responsible for the actual transmission / reception of wireless communication signals on / from the wireless medium.

[0145] exist Figure 20B For clarity, the AP 2000B may include many other components not shown. Only those components most relevant to this disclosure are illustrated.

[0146] This disclosure can be implemented by software, hardware, or software that works with hardware.

[0147] Each functional block used in the description of each of the above embodiments may be implemented partially or entirely by an LSI such as an integrated circuit, and each process described in each embodiment may be controlled partially or entirely by the same LSI or a combination of LSIs. An LSI may be formed as a single chip, or it may be formed as a single chip to include some or all of the functional blocks. An LSI may include data inputs and outputs coupled thereto. The LSI here may be referred to as an IC, system LSI, super LSI, or ultra-LSI, depending on the degree of integration. However, the technology for implementing integrated circuits is not limited to LSIs and can be implemented using dedicated circuitry, general-purpose processors, or special-purpose processors. Alternatively, an FPGA (Field-Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connections and settings of the circuit cells within the LSI, can be used. Due to advancements in semiconductor technology or other derivative technologies, this disclosure can be implemented as digital or analog processing.

[0148] If circuit integration technologies to replace LSIs emerge due to advancements in semiconductor technology or other technologies derived from it, then future integrated circuit technologies can be used to integrate functional blocks. Another possibility is biotechnology and / or similar applications.

[0149] [Industrial Applicability]

[0150] This disclosure can be applied to methods for random access in multi-user wireless communication systems.

[0151] [List of Reference Symbols]

[0152] 1900A, 1900B STA

[0153] 1904 Receiver Signal Processing Circuit

[0154] 1906 Receiving Unit

[0155] 1910, 2010 power supplies

[0156] 1920, 2020 memory

[0157] 1930, 2030 CPU

[0158] 1940, 2040 Auxiliary storage

[0159] 1950, 2050 wireless interfaces

[0160] 1960 and 2060 PHY modules

[0161] 1970 and 2070 antennas

[0162] 1980 and 2080 MAC modules

[0163] 1982 UORA Circuit

[0164] 1984 Energy-saving circuit

[0165] Message processing circuits 1986 and 2084

[0166] 2000A, 2000B AP

[0167] 2004 Transmission Signal Generation Circuit

[0168] 2006 Transmitting Unit

[0169] 2082 RU allocation and scheduling circuit

[0170] 2090 Wired Communication Interface

Claims

1. An integrated circuit for controlling the process of a communication device as a 20MHz operator station, the integrated circuit comprising: At least one input that receives input; as well as The control circuit coupled to the at least one input includes a process of the following operations: Receive a trigger frame for allocating a resource unit (RU) for random access and other frames including random access parameter elements, the random access parameter elements including a first field indicating the minimum value of the OFDMA contention window (OCWmin), wherein the RU includes at least one RU restricted to the 20MHz operating station; as well as The OCWmin is used to control the uplink OFDMA-based random access UORA procedure, which includes: If the OFDMA backoff OBO counter is not greater than the number of available RUs for random access in the trigger frame, the OBO counter is set to zero, where the available RUs are RUs not limited to 20MHz operator stations. as well as If the OBO counter is greater than the number of available RUs for random access, the OBO counter is reduced by the number of available RUs for random access.

2. The integrated circuit of claim 1, wherein, The other frame is one of the beacon frame and the probe response frame.

3. The integrated circuit of claim 1, wherein, The communication device operates only at a channel width of 20MHz.

4. The integrated circuit of claim 1, wherein, The random access parameter element includes a second field indicating the maximum OCW value OCWmax, and the process includes: Set the OCW value within the range of OCWmin and OCWmax; and The OBO counter is initialized to an integer value between 0 and the OCW value.

5. The integrated circuit according to claim 1, wherein The receiver of the trigger frame is a station device operating on the main 20MHz channel bandwidth; and The available RUs for random access are RUs that are not limited to those used for the station device within the main 20MHz channel bandwidth.

6. The integrated circuit according to claim 1, wherein The receiver of the trigger frame is a 20MHz non-access point only device operating on a 20MHz channel bandwidth.

7. The integrated circuit according to claim 1, wherein The trigger frame includes a public information field and multiple user information fields, each of which includes an identifier subfield and an RU allocation subfield indicating the RU used for uplink data transmission through the station device identified by the identifier subfield.

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