WO2022198546A1

WO2022198546A1 - Methods, apparatuses and systems for triggered transmission opportunity (txop) sharing

Info

Publication number: WO2022198546A1
Application number: PCT/CN2021/082903
Authority: WO
Inventors: Zhiqiang Han; Bo Sun
Original assignee: Zte Corporation
Priority date: 2021-03-25
Filing date: 2021-03-25
Publication date: 2022-09-29

Abstract

Methods, apparatuses and systems for avoiding collisions of signals transmitted to a wireless communication node are disclosed herein. In some embodiments, a method includes: transmitting an allocation signal to allocate a first time period for data transmission from a first wireless communication device; and transmitting a collision avoidance signal, wherein the collision avoidance signal prevents a second wireless communication device from accessing a channel used by the first wireless communication device during the first time period.

Description

METHODS, APPARATUSES AND SYSTEMS FOR TRIGGERED TRANSMISSION OPPORTUNITY (TXOP) SHARING

TECHNICAL FIELD

The disclosure relates generally to wireless communications and, more particularly, to methods, apparatuses and systems for avoiding collisions of signals transmitted to a wireless communication node, and methods to further improve transmission efficiencies.

BACKGROUND

Wireless communication is widely affecting society and people’s lives. Many new use cases like factory automations, gaming, emergency communication, Virtual Reality (VR) , Augmented Reality (AR) , etc. demand the rapid growth of wireless communications to provide low latency and high throughput for such services. A wireless LAN (WLAN) is a wireless computer network that links two or more devices using wireless communication to form a local area network (LAN) within a limited area such as a home, school, campus or office building. Most modern WLANs are based on IEEE 802.11 standards. The basic service set (BSS) is the basic building block of an IEEE 802.11 LAN. An infrastructure BSS includes the BSS with stations (STAs) through associating with an Access Point (AP) to connect to the Internet. In cellular network, radio access network are composed of base stations and user equipment (UE) . UEs are associated with a base station and UEs connect to the Internet through a base station.

Regardless whether it is cellular network, WLAN or other networks, point to point communication is becoming more and more important. Unfortunately, with increased user demand and network density, network performance issues can arise. One performance issue is the issue of hidden devices in a wireless communication system that results in collisions of signals transmitted to a wireless communication node from stations. In the industry, hidden devices can also be referred to as hidden nodes. The methods, apparatuses and systems, as described herein, can improve the quality and performance for a wireless communication nodes by implementing collision avoidance technology.

SUMMARY

The exemplary embodiments disclosed herein are directed to solving the issues relating to one or more of the problems presented in the prior art, as well as providing additional features that will become readily apparent by reference to the following detailed description when taken in conjunction with the accompany drawings. In accordance with various embodiments, exemplary systems, methods, devices and computer program products are disclosed herein. It is understood, however, that these embodiments are presented by way of example and not limitation, and it will be apparent to those of ordinary skill in the art who read the present disclosure that various modifications to the disclosed embodiments can be made while remaining within the scope of the present disclosure.

In some embodiments, a method performed by a wireless communication node to avoid collisions of signals transmitted to the wireless communication node includes transmitting an allocation signal to allocate a first time period for data transmission from a first wireless communication device; and transmitting a collision avoidance signal, where the collision avoidance signal prevents a second wireless communication device from accessing a channel used by the first wireless communication device during the first time period. In one embodiment, the collision avoidance signal may comprise a downlink (DL) signal that indicates a second time period for exchanging data, where the second time period ends later than the first time period, and where the allocation signal is transmitted after transmitting the DL signal. In another embodiment, the collision avoidance signal may comprise a clear-to-send (CTS) to-self signal transmitted by the wireless communication node to itself, where the allocation signal is transmitted before transmitting the CTS to-self signal.

In some embodiments, a method performed by a wireless communication node to avoid collisions of signals transmitted to the wireless communication node comprises determining whether to allocate a first time period for transmission of uplink (UL) data or peer-to-peer (P2P) data from a first wireless communication device. When it is determined to allocate the first time period for transmission of UL data from the first wireless communication device, transmitting an allocation signal and a collision avoidance signal, and when it is determined to allocate the first time period for transmission of P2P data from the wireless communication device, transmitting the allocation signal without transmitting the collision avoidance signal. The allocation signal indicates the first time period, and the collision avoidance signal prevents a second wireless communication device from initiating a contention protocol to access a channel used by the first wireless communication device during the first time period.

In some embodiments, a non-transitory computer readable medium storing computer-executable instructions that when executed performs any one of the methods of claims 1-10.

BRIEF DESCRIPTION OF THE DRAWINGS

Various exemplary embodiments of the present disclosure are described in detail below with reference to the following Figures. The drawings are provided for purposes of illustration only and merely depict exemplary embodiments of the present disclosure to facilitate the reader’s understanding of the present disclosure. Therefore, the drawings should not be considered limiting of the breadth, scope, or applicability of the present disclosure. It should be noted that for clarity and ease of illustration these drawings are not necessarily drawn to scale.

FIG. 1 illustrates a method for a WLAN network to reset a network allocation vector (NAV) in a hidden node scenario, in accordance with some embodiments of the present disclosure.

FIG. 2 illustrates a frame exchange process to support peer-to-peer (P2P) resource allocation in a wireless local area network (WLAN) , in accordance with some embodiments of the present disclosure.

FIG. 3 illustrates a frame exchange process for a method of avoiding a collision of signals between two or more wireless communication devices, in accordance with some embodiments of the present disclosure.

FIG. 4 illustrates a frame exchange process for another method of avoiding a collision of signals between two or more wireless communication devices, in accordance with some embodiments of the present disclosure.

FIG. 5 illustrates a flowchart describing the transmission of an allocation frame for uplink (UL) traffic, in accordance with some embodiments of the present disclosure.

FIG. 6 illustrates a frame exchange process for a method of traffic priority indication, in accordance with some embodiments of the present disclosure.

FIG. 7 illustrates a frame exchange process for a method to provide a P2P buffer status report, in accordance with some embodiments of the present disclosure.

FIG. 8 illustrates a block diagram of a network node configured to carry out the methods and techniques disclosed in the present disclosure, in accordance with some embodiments.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

Various exemplary embodiments of the present disclosure are described below with reference to the accompanying figures to enable a person of ordinary skill in the art to make and use the present disclosure. As would be apparent to those of ordinary skill in the art, after reading the present disclosure, various changes or modifications to the examples described herein can be made without departing from the scope of the present disclosure. Thus, the present disclosure is not limited to the exemplary embodiments and applications described and illustrated herein. Additionally, the specific order and/or hierarchy of steps in the methods disclosed herein are merely exemplary approaches. Based upon design preferences, the specific order or hierarchy of steps of the disclosed methods or processes can be re-arranged while remaining within the scope of the present disclosure. Thus, those of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or acts in a sample order, and the present disclosure is not limited to the specific order or hierarchy presented unless expressly stated otherwise.

As discussed herein, a “wireless communication node” can include, or be implemented as, a WLAN access point (AP) , a base station (BS) , a next Generation Node B (gNB) , and an E-UTRAN Node B (eNB) , in accordance with the customary understanding of these terms in the art. Furthermore, as discussed herein, a “wireless communication device” can include, or be implemented as, a mobile terminal, a mobile station, a work station and a user equipment device (UE) , in accordance with the customary understanding of these terms in the art. In the description of exemplary embodiments below, an AP is described as an exemplary embodiment of a “wireless communication node” and a mobile station (STA) is described as an exemplary embodiment of a “wireless communication device. ” It should be understood, however, that the scope of the present disclosure is not limited to these exemplary embodiments.

The methods, apparatuses and systems described herein apply to wireless communication systems including wireless local area networks (WLAN) . In accordance with some embodiments, this document describes techniques, mechanisms, devices, and systems for transmission opportunity sharing in accordance with the IEEE 802.11 protocol standards. Basic service sets (BSS) are a basic building block of an IEEE 802.11 LAN. Each BSS area roughly corresponds to the coverage of a number of stations. A central concept of a BSS is that all stations must ‘hear’ each other, that is, be within radio or optical range. An infrastructure BSS is created by an infrastructure device called an access point (AP) for other devices to join. The operating parameters of the infrastructure BSS are defined by the AP. An infrastructure BSS may include multiple stations (i.e., STAs or non-AP STAs) and one access point (i.e., AP) which serves at least one station (STA) and provides station management and access to the local area network (LAN) .

In an IEEE 802.11 network, the following definitions can apply: (1) a station (STA) is the basic addressable unit for 802.11 communication, and is a logical entity that is a singly addressable instance of a medium access control (MAC) and physical layer (PHY) interface to the wireless medium (WM) ; (2) an access point (AP) is an entity that serves at least one station (STA) and provides access to distribution system services, via the wireless medium (WM) for associated STAs. An AP comprises a STA and a distribution system access function (DSAF) ; (3) non-access-point (non-AP) station (STA) refers to a STA that is not contained within an access point (AP) .

In a wireless communication system, it is important to manage the communication between network nodes and stations. Transmit opportunity (TXOP) is a MAC layer feature used in a IEEE 802.11-based wirelesses local area network ( (WLAN) . TXOP defines the time duration for which a station can send frames after it has gained contention for the transmission medium. By providing this contention-free time period, TXOP aims to increase the throughput of high priority data, such as voice and video.

In some embodiments, when a station in the wireless communication network has frames to transmit, the station waits until it’s network allocation vector (NAV) decrements to zero. Essentially, the NAV may be considered a counter, which counts down to zero at a uniform rate. The NAV maintains a prediction of future traffic on the medium based on duration information that is contained in most frames. A non-zero NAV value indicates that the channel is busy. Therefore, a STA having a non-zero NAV value will not contend for the channel. When the NAV value decrements to zero, it indicates that the channel is free and STAs having a NAV value equal to zero can contend for the channel. If multiple wireless devices transmit on the same channel at the same time, the signals may collide and interfere with each other. When this happens, the stations must wait for another opportunity to transmit and try again.

In some embodiments, in wireless networks, the hidden node problem or hidden terminal problem occurs when a node can communicate with a wireless access point (AP) , but cannot directly communicate with other nodes that are communicating with that AP. This can lead to difficulties in medium access control (MAC) sublayer functions since multiple devices can send data packets to the AP simultaneously, which creates interference and collisions at the AP resulting in frame packet collisions.

In some embodiments within an obtained TXOP by an AP, an allocation frame can initiate an allocation time period. The allocation frame can be considered a trigger frame and in some embodiment is a multi-user request to sent (MU-RTS) TXOP Sharing (TXS) Trigger frame, or MU-RTS TXS Trigger frame. A MU-RTS TXS Trigger frame is a form of a MU-RTS Trigger frame. As used herein, the term “allocation signal” is used to generally refer to an allocation frame, which includes MU-RTS TXS trigger frames, MU-RTS trigger frames and single use (SU) allocation frames. The allocation time period is a period where stations can transmit frames, i.e., provide uplink (UL) transmissions.

In some embodiments, an AP can transmit a collision avoidance signal in order to avoid collisions in a hidden mode environment. These embodiments are effective to support uplink (UL) data transmission from a first wireless device (or STA) to a wireless communication node (or AP) . The following two exemplary embodiments of a collision avoidance signal are described herein: (1) transmit by the AP an exchange frame via a downlink (DL) signal before transmitting an allocation frame; (2) transmit by the AP a CTS-to-self signal after transmitting the allocation frame. These embodiments are discussed herein relative to FIG. 3 and FIG. 4, respectively.

FIG. 1 illustrates an exemplary WLAN network 100 in which a hidden device scenario can occur. One BSS includes AP1 102, STA1 104, STA2 106, STA3 108 and other STAs. STA1 104 and STA3 108 are hidden from each other, i.e., STA1 104 cannot hear STA3 108 and STA3 108 cannot hear STA1 104. The left circle 110 is the transmission coverage of STA1 104 (and STA2 106) and the right circle 112 is the transmission coverage of STA3 108. As shown in FIG. 1, STA1 104 is not within the coverage 112 of STA3 108 and STA3 103 is not within the coverage area 110 of STA1 104. However, STA2 106 is in the transmission coverage area 110 of STA1 104 but outside the coverage area 112 of STA3 108. Therefore, STA2 106 can detect and decode frames transmitted by STA1 104, but it cannot detect and decode frames transmitted by STA3 108.

In the environment of FIG. 1, the AP1 102 allocates time within an obtained TXOP to STA1 104 by transmitting an allocation frame. After transmitting a clear-to-send (CTS) , STA1 104 transmits PHY protocol data unit (PPDU) to AP1 104 in the allocated time period. When STA3 108 receives the allocation frame, STA3 108 updates its network allocation vector (NAV) based on the duration information in the allocation frame. But if no PHY-RXSTART. indication primitive is received from the PHY layer of STA3 108 during a NAVTimeout period starting when the MAC layer of STA3 108 receives a PHY-RXEND. indication primitive corresponding to the detection of the MU-RTS TXS Trigger frame, STA3 108 will reset its NAV and contend for the wireless medium to access the channel allocated to STA1 104. If STA3 108 transmits a PPDU to AP1 104, this transmission will collide with the transmission of STA1 104, which will adversely affect the transmission efficiency.

FIG. 2 illustrates a frame exchange process 200 to support peer-to-peer (P2P) resource allocation in a wireless local area network (WLAN) , in accordance with conventional techniques. AP1 102 obtains a transmission opportunity (TXOP) , “AP TXOP” . An AP TXOP can be referred to as a “TXOP owned by AP” . In some embodiments, AP1 102 allocates time within the AP TXOP to STA1 104 by transmitting an allocation frame 202, which indicates a first time period (T) allocated to STA1 104, a receiver address (RA) corresponding to an address of STA1 104, which enables STA1 104 to decode the allocation frame 202. After STA1 104 receives and decodes the allocation frame from AP1 102, STA1 104 responds and transmits a clear-to-send (CTS) 204 frame to AP1 102. After transmitting the CTS 204, STA1 104 can transmit a PPDU 206 to AP1 102, or STA2 106, for example, in the allocated time period. As illustrated in FIG. 2, STA2 106 responds and transmits a block acknowledgement (BA) 208 to STA1 104. STA1 104 and STA2 106 repeat the cycle with STA1 104’s transmission of PPDU 210 and STA2’s response of a transmission of BA 212 to AP1 102. The transmission period for TXOP sharing based on the allocation frame cannot exceed the allocated period. At this point the allocated time period terminates. As illustrated, AP1 102 proceeds to transmit downlink (DL) data signal 214 from AP1 102 to STA1 102 or other STAs. In response, the stations that received the DL data signal 214, transmit a BA 216 to AP1 102. The transmission of DL data signal 214 and BA 216 response can be referred to as a frame exchange.

As discussed above, the allocation frame, which can be a MU-RTS TXS Trigger frame, for example, a STA such as STA3 108 (Fig. 1) that receives the MU-RTS Trigger frame will use information from the MU-RTS Trigger frame as the most recent basis to update its NAV setting and will reset its NAV if no PHY-RXSTART. indication primitive is received from the PHY layer during a NAVTimeout period starting when the MAC layer receives a PHY-RXEND. indication primitive corresponding to the detection of the MU-RTS Trigger frame. Upon resetting its NAV, STA3 108 will start contending for access to a channel that may be in use by STA1 104, resulting in potential collisions of signals transmitted by STA1 104 and STA3 108.

FIG. 3 illustrates a frame exchange process 300 for a method of avoiding collisions of signals between two or more wireless communication devices, in accordance with some embodiments of the present disclosure. In this embodiment, before AP1 102 transmits an allocation frame 302, AP1 102 transmits will transmit a collision avoidance signal within the same AP TXOP. In accordance with some embodiments, the collision avoidance signal is a DL signal 618, which contains duration information that indicates an end point in time that is after an end point in time indicated by duration information contained in the allocation signal. In some embodiments, the DL data signal carries first duration information, and the allocation frame carries two types of information: second duration information and an allocation time period (i.e., a first time period) . In some embodiments, the wireless communication node may compare the first duration information with the second duration information to ensure that an end point in time indicated by the first duration information is after an end point in time indicated by the second duration information. In this case, STA3 108 will not update its NAV based on the duration information from the allocation frame as the most recent basis. So STA3 108 will not reset its NAV and not contend for access to a channel provided by the AP1 102 during the allocated time period, thereby avoiding potential collisions with STA1 104 that is using the channel during the allocated time period.

Specifically, as illustrated in FIG. 3, frame exchange process 300 comprises the following: First, AP1 102 obtains a transmission opportunity (TXOP) , “AP TXOP. ” An AP TXOP can be referred to as a “TXOP owned by AP. ” Next, the AP1 102 transmits a downlink (DL) signal to STA1 104 to initiate the frame exchange, wherein the DL signal 318 is a collision avoidance signal that contains the first duration information that is used by STAs to update its network allocation vector (NAV1) period, wherein completion of transmission of the DL signal 318 initiates the NAV1 period for frame exchange. Next, the AP1 102 receives a block ACK (BA) signal 320 from the STA1 102, and then the AP1 102 transmits an allocation frame 302, which contains an allocated time period (T) for frame exchange and the second duration information that is used by the STA1 102 to update its NAV2 period, wherein completion of transmission of the allocation frame 302 initiates the NAV2 period for frame exchange. As discussed above, although all STAs within the coverage area of the AP1 102 can receive the allocation frame 302, only STA1 104 is able to decode it. Next, the AP1 102 receives a CTS 304 from the STA1 104 and thereafter receives an UL transmission from the STA1 104 comprising a PHY protocol data unit (PPDU) 306. The AP1 102 then transmits a block ACK (BA) 308 to the STA1 104 and then receives another UL transmission from the STA1 102 comprising a PPDU 310, followed by transmitting a BA 312 to the STA1 102, at the end of the NAV1 period that is set based on the first duration information contained in the DL signal 318.

As previously noted, duration information indicated by the DL signal 318 may cause the STA1 104, and other STAs, to update its NAV to the NAV1 period if the time period information satisfies certain conditions (e.g., the duration information is larger than the NAV period) . Similarly, the second duration information indicated by the allocation frame 302 may cause the STA1 104, and other STAs, to update its NAV to the NAV2 period. As shown in FIG. 3, the end point of NAV1 is after the end point of the NAV2 period, which will result in a hidden device (e.g., STA3 108) to not update its NAV information based on the allocation frame as a most recent basis, thereby preventing the STA3 108 from initiating a contention process for a channel provided by AP1 102.

FIG. 4 illustrates a frame exchange process 400 for avoiding a collision of signals between two or more wireless communication devices, in accordance with alternative embodiments of the present disclosure. As illustrated in FIG. 4, the AP1 102 transmits an allocation signal 402 (e.g., a MU-RTS TXS trigger frame) to STA1 104, which indicates an allocation time period (e.g., a first time period) . In response to receiving the allocation signal 402, the STA1 104 transmits a response frame (e.g., a clear-to-send (CTS) frame) to the AP1 102. After AP1 102 receives the response frame from STA1 104, AP1 102 transmits a CTS-to-Self signal 405. Because the AP1 102 transmits the CTS-to-self frame within the TXOP, any STAs within the coverage area of AP1 102 (e.g., STA3 108) will receive a primitive indication, which indicates a new reception is starting, so the STAs will not reset their NAVs. If the NAV is not zero, it means the channel is busy, and the STAs will not contend for the channel, thereby avoiding the hidden device problem and potential collisions, as described above.

After transmitting the CTS-to-self frame, AP1 102 proceeds to receive an UL transmission from the STA1 104 comprising a PHY layer protocol data unit (PPDU) 406. AP1 102 then transmits a block ACK (BA) 408 to the STA1 104 and repeats the steps of receiving, by the AP1 102, an UL transmission from the STA1 102 comprising a PPDU 410, and transmitting, by the AP1 102, a BA 412 to the STA1 102.

FIG. 5 illustrates a flowchart 500 describing a method for transmission of an allocation frame for uplink (UL) traffic, in accordance with some embodiments of the present disclosure. The method comprises the steps of:

- Whether to transmit allocation frame for UL traffic; (step 502)

- If Yes, transmitting the allocation frame and the collision avoidance signal to support UL traffic; (step 504)

- If No, proceed with transmitting the allocation frame without transmitting the collision avoidance signal; (step 506)

If the answer at step 502 is “Yes, ” in some embodiments, the collision avoidance signal can include a DL signal 318, as described above with reference to FIG. 3, and step 504 of FIG. 5 performs the frame exchange process 300 of FIG. 3, as described above. In alternative embodiments, the collision avoidance signal includes a CTS-to-self signal 404, as described above with reference to FIG. 4, and step 504 of FIG. 5 performs the frame exchange process 400 of FIG. 4, as described above. If the answer at step 502 is “No, ” then the frame exchange process 200 of FIG. 2, as described above, is performed at step 506.

In some embodiments, further improved methods for avoidance of transmission collisions can include an indication of traffic direction allowed in the allocation period. The traffic direction may be a preferred direction, in accordance with some embodiments. In some embodiments, the traffic direction indicates at least one of UL only, P2P only and both allowed. When the traffic direction indicates UL only, it means a scheduled STA only transmits UL traffic. When the traffic direction indicates P2P only, it means a scheduled STA only transmits P2P traffic. When the traffic direction indicates both are allowed, it means a scheduled STA can transmit UL traffic and/or P2P traffic. In some embodiments, when the allocation signal indicates that both UL traffic and P2P traffic are allowed to be transmitted during the first time period, a preferred direction of transmission is indicated in the allocation signal.

If the traffic direction indicates UL traffic only, or both UL and P2P traffic, AP1 102 sends both the allocation frame and a collision avoidance signal, as described above with respect to step 504 of FIG. 5. If the traffic direction indicates P2P only, a STA that used information from an MU-RTS TXOP TXS Trigger frame as the most recent basis to update its NAV setting is permitted to reset its NAV if no PHY-RXSTART. indication primitive is received from the PHY during a NAVTimeout period starting when the MAC receives a PHY-RXEND. indication primitive corresponding to the detection of the MU-RTS TXOP TXS Trigger frame. In this case, the AP1 102 sends the allocation frame without also sending a collision avoidance signal, as described above with respect to step 506 of FIG. 5.

FIG. 6 illustrates a frame exchange process 600 for indicating a traffic type priority, in accordance with some embodiments of the present disclosure. In order to improve transmission opportunity sharing and make better use of the scheduled time period, it is desirable to ensure the transmission of data for high priority services. For better scheduling, AP indicate the scheduling priority of data to be transmitted during allocated time periods. That is, the allocation frame indicates which traffic will be transmitted first in the allocated frame 602. In some embodiments, the service priority indicates a preferred AC (Access Category) or a preferred TID (Traffic Identification) for data to be transmitted before lower priority data.

In some embodiments, when the scheduled STA receives allocation frame 602, based on scheduling priority information contained in the allocation frame 602, the scheduled STA can transmit QoS Data in the following order: First, any and all QoS Data that correspond to the Preferred AC or the preferred TID. Second, any and all QoS Data that correspond to any AC that has a higher priority. Third, any QoS Data that correspond to any AC that has a lower priority. The other frame elements in frame exchange process 600 are equivalent to their corresponding frame elements in frame exchange process 300. This includes CTS 604, PPDU 606, BA 608, PPDU 610, BA 612, DL data signal 614, BA 616, DL data signal 618 and BA 620. Therefore, a discussion of these frames is not repeated here.

FIG. 7 illustrates a frame exchange process 700 of a method to provide a buffer status report, in accordance with some embodiments of the present disclosure. The AP (e.g., AP1 102) transmits a request frame 722 to the STA (e.g., STA1 104) , which requests the buffer status for data to be transmitted by the STA. In some embodiments, the request frame indicates a particular traffic type (e.g., P2P traffic) for which the STA should provide a buffer status report. In some embodiments, the request frame also indicates the destination of the reported traffic. Next, the STA transmits a response frame 724 that reports the buffer status for P2P traffic.

In order to make the scheduling time more accurate and effective, a STA can deliver P2P buffer status reports to assist its AP in allocating time resources. In accordance with various embodiments, the STA can further indicate the traffic direction. The STA can either implicitly deliver P2P buffer status reports in the QoS Control field or HT control field of any frame transmitted to the AP or explicitly deliver P2P buffer status reports in any frame transmitted to the AP in response to a request frame 722.

As shown in FIG. 7, the AP transmits a request frame 722 before the transmission of the allocation frame 702, in accordance with some embodiments. In some embodiments, a traffic type is indicated in the request frame 722, and the traffic type contains at least one type of P2P traffic. Upon receiving the request frame 722, the STA transmits a response frame 724 to report its P2P buffer status. The STA can either implicitly deliver P2P buffer status reports in the QoS Control field or HT control field of any frame transmitted to the AP. Further, the destination of the reported traffic should be indicated in the response frame 724 or other wireless frame. Further, when both UL traffic and P2P traffic are allowed to be transmitted in the allocated time period, the preferred transmission direction should be indicated in the allocation frame. For example, a preferred transmission direction may instruct the STA to first transmit P2P traffic to another STA, and after transmission of P2P traffic is completed, the STA can transmit UL traffic to the AP.

After transmission of the response frame 724, any one of frame exchange processes described above with respect to FIGS. 2-4 can be performed, in accordance with various embodiments. For example, an allocation frame 702 can be transmitted, followed by a CTS frame 704, PPDU 706, BA 708, etc., which are similar to allocation frame 302, CTS 304, PPDU 306 and BA 308, described with respect to FIG. 3 above.

In summary, the methods and apparatus described in embodiments relative to FIGs. 3-7 may improve the transmission efficiency of a wireless communication system including avoiding the collision of signals between wireless communication devices and wireless communication nodes. The improvements described herein include the following: (1) When the scheduled traffic type in the allocation frame is UL traffic, before an AP sends the allocation frame, the AP can execute another frame exchange in the same TXOP. The end point of the NAV indicated by the frame exchange is after the end point of the NAV indicated by the allocation frame; (2) If the traffic direction indicates P2P only, a NAV reset is allowed by by a hidden STA; (3) An AP transmits the allocation frame which indicates an allocated time period for a first STA to use a channel provided by the AP.

In some embodiments, the allocation frame further indicates a service priority for data to be transmitted by the scheduled STA. In some embodiments, the service priority at least indicates the preferred AC or the preferred TID; (4) In some embodiments, the STA can either implicitly deliver P2P buffer status reports in the QoS Control field or HT control field of any frame transmitted to the AP or explicitly deliver P2P buffer status reports in any frame sent to the AP in response to a request frame; (5) In some embodiments, an AP can transmit a request frame before the transmission of the allocation frame. The traffic type can be indicated in the request frame. The traffic type contains at least one type of P2P traffic; (6) In some embodiments, when both UL traffic and P2P traffic are allowed to transmit in the allocated time period, the preferred transmission direction can be indicated in the allocation frame.

FIG. 8 illustrates a block diagram of a network node (NN) 800 configured to carry out the methods and techniques disclosed in the present disclosure, in accordance with some embodiments. The NN 800 is an example of a wireless communication device or wireless communication node that can be configured to implement the various methods described herein. In some embodiments, the NN 800 may be wireless communication node such as a WLAN access point (AP) , as described herein. In other embodiments, the NN 800 may be a wireless communication device such as a mobile station (STA) , as described herein. As shown in Figure 8, the NN 800 includes a housing 840 containing a system clock 802, a processor 804, a memory 806, a transceiver 810 comprising a transmitter 812 and receiver 814, a power module 808, and a TXOP module 820. The TXOP module 820 can select or reselect a transmission opportunity for providing improved transmission efficiencies and avoidance of collisions among wireless communication devices, in accordance with the methods described herein.

In this embodiment, the system clock 802 provides the timing signals to the processor 804 for controlling the timing of all operations of the NN 800. The processor 804 controls the general operation of the NN 800 and can include one or more processing circuits or modules such as a central processing unit (CPU) and/or any combination of general-purpose microprocessors, microcontrollers, digital signal processors (DSPs) , field programmable gate array (FPGAs) , programmable logic devices (PLDs) , controllers, state machines, gated logic, discrete hardware components, dedicated hardware finite state machines, or any other suitable circuits, devices and/or structures that can perform calculations or other manipulations of data.

The memory 806, which can include both read-only memory (ROM) and random access memory (RAM) , can provide instructions and data to the processor 804. A portion of the memory 806 can also include non-volatile random access memory (NVRAM) . The processor 804 typically performs logical and arithmetic operations based on program instructions stored within the memory 806. The instructions (a.k.a., software) stored in the memory 806 can be executed by the processor 804 to perform the methods described herein. The processor 804 and memory 806 together form a processing system that stores and executes software. As used herein, “software” means any type of instructions, whether referred to as software, firmware, middleware, microcode, etc. which can configure a machine or device to perform one or more desired functions or processes. Instructions can include code (e.g., in source code format, binary code format, executable code format, or any other suitable format of code) . The instructions, when executed by the one or more processors, cause the processing system to perform the various functions described herein.

The transceiver 810, which includes the transmitter 812 and receiver 814, allows the NN 800 to transmit and receive data to and from an external network node (e.g., a STA or AP) . An antenna 850 is typically attached to the housing 840 and electrically coupled to the transceiver 810. In various embodiments, the NN 800 includes (not shown) multiple transmitters, multiple receivers, and multiple transceivers. In some embodiments, the antenna 850 includes a multi-antenna array that can form a plurality of beams each of which points in a distinct direction in accordance with MIMO beamforming techniques.

The TXOP module 820 may be implemented as part of the processor 804 programmed to perform the functions herein, or it may be a separate module implemented in hardware, firmware, software or a combination thereof. In accordance with various embodiments, the NN 800 is a wireless communication node, and the TXOP module 820 and transceiver 810 are configured to perform the methods of FIGs 3, 4, 5, 6 and 7, as described above. In some embodiments, the TXOP module 820 can be implemented as software (i.e., computer executable instructions) stored in a non-transitory computer-readable medium that when executed by processor 804, transform the processor 804 into a special-purpose computer to perform the wireless communication device capability confirmation methods and operations described herein.

The various components and modules discussed above within housing 840 are coupled together by a bus system 830. The bus system 830 can include a data bus and, for example, a power bus, a control signal bus, and/or a status signal bus in addition to the data bus. It is understood that the modules of the NN 800 can be operatively coupled to one another using any suitable techniques and mediums. It is further understood that additional modules (not shown) may be included in the NN 800 without departing from the scope of the disclosure.

While various embodiments of the present disclosure have been described above, it should be understood that they have been presented by way of example only, and not by way of limitation. Likewise, the various diagrams may depict an example architectural or configuration, which are provided to enable persons of ordinary skill in the art to understand exemplary features and functions of the present disclosure. Such persons would understand, however, that the present disclosure is not restricted to the illustrated example architectures or configurations, but can be implemented using a variety of alternative architectures and configurations. Additionally, as would be understood by persons of ordinary skill in the art, one or more features of one embodiment can be combined with one or more features of another embodiment described herein. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments.

It is also understood that any reference to an element herein using a designation such as “first, ” “second, ” and so forth does not generally limit the quantity or order of those elements. Rather, these designations can be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements can be employed, or that the first element must precede the second element in some manner.

Additionally, a person having ordinary skill in the art would understand that information and signals can be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits and symbols, for example, which may be referenced in the above description can be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

A person of ordinary skill in the art would further appreciate that any of the various illustrative logical blocks, modules, processors, means, circuits, methods and functions described in connection with the aspects disclosed herein can be implemented by electronic hardware (e.g., a digital implementation, an analog implementation, or a combination of the two) , firmware, various forms of program or design code incorporating instructions (which can be referred to herein, for convenience, as “software” or a “software module) , or any combination of these techniques.

To clearly illustrate this interchangeability of hardware, firmware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware, firmware or software, or a combination of these techniques, depends upon the particular application and design constraints imposed on the overall system. Skilled artisans can implement the described functionality in various ways for each particular application, but such implementation decisions do not cause a departure from the scope of the present disclosure. In accordance with various embodiments, a processor, device, component, circuit, structure, machine, module, etc. can be configured to perform one or more of the functions described herein. The term “configured to” or “configured for” as used herein with respect to a specified operation or function refers to a processor, device, component, circuit, structure, machine, module, etc. that is physically constructed, programmed and/or arranged to perform the specified operation or function.

Furthermore, a person of ordinary skill in the art would understand that various illustrative logical blocks, modules, devices, components and circuits described herein can be implemented within or performed by an integrated circuit (IC) that can include a general purpose processor, a digital signal processor (DSP) , an application specific integrated circuit (ASIC) , a field programmable gate array (FPGA) or other programmable logic device, or any combination thereof. The logical blocks, modules, and circuits can further include antennas and/or transceivers to communicate with various components within the network or within the device. A general purpose processor can be a microprocessor, but in the alternative, the processor can be any conventional processor, controller, or state machine. A processor can also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein.

If implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium. Thus, the steps of a method or algorithm disclosed herein can be implemented as software stored on a computer-readable medium. Computer-readable media includes both computer storage media and communication media including any medium that can be enabled to transfer a computer program or code from one place to another. A storage media can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

In this document, the term “module” as used herein, refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for purpose of discussion, the various modules are described as discrete modules; however, as would be apparent to one of ordinary skill in the art, two or more modules may be combined to form a single module that performs the associated functions according embodiments of the present disclosure.

Additionally, memory or other storage, as well as communication components, may be employed in embodiments of the present disclosure. It will be appreciated that, for clarity purposes, the above description has described embodiments of the present disclosure with reference to different functional units and processors. However, it will be apparent that any suitable distribution of functionality between different functional units, processing logic elements or domains may be used without detracting from the present disclosure. For example, functionality illustrated to be performed by separate processing logic elements, or controllers, may be performed by the same processing logic element, or controller. Hence, references to specific functional units are only references to a suitable means for providing the described functionality, rather than indicative of a strict logical or physical structure or organization.

Various modifications to the implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other implementations without departing from the scope of this disclosure. Thus, the disclosure is not intended to be limited to the implementations shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as recited in the claims below.

Claims

A method performed by a wireless communication node to avoid collisions of signals transmitted to the wireless communication node, the method comprising:

transmitting an allocation signal to allocate a first time period for data transmission from a first wireless communication device; and

transmitting a collision avoidance signal, wherein the collision avoidance signal prevents a second wireless communication device from accessing a channel used by the first wireless communication device during the first time period.
The method of claim 1, wherein:

the collision avoidance signal comprises a downlink (DL) signal that contains first duration information,

the allocation signal contains second duration information,

the first duration information indicates a first end point in time that is later than a second end point in time indicated by the second duration information, and

the allocation signal is transmitted after transmitting the DL signal.
The method of claim 1, wherein collision avoidance signal comprises a clear-to-send (CTS) to-self signal transmitted by the wireless communication node to itself, wherein the allocation signal is transmitted before transmitting the CTS to-self signal.
The method of claim 1, wherein:

the wireless communication node comprises an access point (AP) , the first and second wireless communication devices comprises first and second mobile stations (STAs) , respectively.
The method of claim 4, further comprising:

receiving a clear-to-send (CTS) signal from the first wireless communication device;

receiving an uplink (UL) transmission from the first wireless communication device; and

transmitting a second BA to the first wireless communication device.
The method of claim 5, wherein:

the allocation signal comprises a multi-user request to send (MU-RTS) Trigger frame, and

the first time period comprises a transmission opportunity (TXOP) sharing period for UL transmission.
The method of claim 1, wherein the allocation signal indicates service priorities that instruct the first wireless communication device which types of data should be transmitted first within the first time period.
The method of claim 1, further comprising:

transmitting a request signal to obtain a buffer status of the first wireless communication device;

receiving a response signal from the first wireless communication device, wherein the response signal indicates the buffer status; and

determining the first time period based on the buffer status.
The method of claim 8, wherein the request signal indicates at least one type of peer-to-peer (P2P) traffic to be included in the buffer status reported by the first wireless communication device.
The method of claim 1, wherein:

the allocation signal indicates at least one type of traffic allowed to be transmitted during the first time period, and

when the allocation signal indicates that both UL traffic and peer-to-peer (P2P) traffic are allowed to be transmitted during the first time period, a preferred direction of transmission is indicated in the allocation signal.
A method performed by a wireless communication node to avoid collisions of signals transmitted to the wireless communication node, the method comprising:

determining whether to allocate a first time period for transmission of uplink (UL) data or peer-to-peer (P2P) data from a first wireless communication device;

when it is determined to allocate the first time period for transmission of UL data from the first wireless communication device, transmitting an allocation signal and a collision avoidance signal; and

when it is determined to allocate the first time period for transmission of P2P data from the wireless communication device, transmitting the allocation signal without transmitting the collision avoidance signal,

wherein the allocation signal indicates the first time period, and the collision avoidance signal prevents a second wireless communication device from initiating a contention protocol to access a channel used by the first wireless communication device during the first time period.
The method of claim 11, wherein:

the collision avoidance signal comprises a downlink (DL) signal that contains first duration information,

the allocation signal contains second duration information,

the first duration information indicates a first end point in time that is later than a second end point in time indicated by the second duration information, and

the allocation signal is transmitted after transmitting the DL.
The method of claim 11, wherein collision avoidance signal comprises a clear-to-send (CTS) -to-self signal transmitted by the wireless communication node to itself, wherein the allocation signal is transmitted before transmitting the CTS-to-self signal.
The method of claim 11, wherein:

the wireless communication node comprises an access point (AP) ,

the first and second wireless communication devices comprises first and second mobile stations (STAs) , respectively.
The method of claim 14, further comprising:

receiving a clear-to-send (CTS) signal from the first wireless communication device;

receiving an uplink (UL) transmission from the first wireless communication device; and

transmitting a second BA to the first wireless communication device.
The method of claim 15, wherein:

the allocation signal comprises a multi-user request to send (MU-RTS) Trigger frame,

the first time period comprises a transmission opportunity (TXOP) sharing period for UL transmission.
The method of claim 11, wherein the allocation signal indicates service priorities that instruct the first wireless communication device which types of data should be transmitted first within the first time period.
The method of claim 11, further comprising:

transmitting a request signal to obtain a buffer status of the first wireless communication device;

receiving a response signal from the first wireless communication device, wherein the response signal indicates the buffer status; and

determining the first time period based on the buffer status.
The method of claim 18, wherein the request signal indicates at least one type of peer-to-peer (P2P) traffic to be included in the buffer status reported by the first wireless communication device.
The method of claim 11, wherein:

the allocation signal indicates at least one type of traffic allowed to be transmitted during the first time period, and

when the allocation signal indicates that both UL traffic and peer-to-peer (P2P) traffic are allowed to be transmitted during the first time period, a preferred direction of transmission is indicated in the allocation signal.
A wireless communication node configured to perform the method of any one of claims 1-10.
A wireless communication node configured to perform the method of any one of claims 11-20.
A non-transitory computer-readable medium storing computer-executable instructions that when executed perform the method of any one of claims 1-20.