System and method using link switching protocol and / or overlapping traffic detection

Abstract

The invention relates to a system and method using a link switching protocol and / or overlapping traffic detection. A wireless device may include a first radio configured to transmit over a first link and a second link of a first wireless frequency band. The first radio device may be configured to detect OBSS communications on the first link of the first wireless frequency band. The wireless device may perform a coordinated link switching (CLS) operation. The wireless device may be configured to operate as an access point (AP) or a station of one or more stations of a wireless network.

Description

[0001] CROSS REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit and priority of Indian Provisional Application No. 202321056178 filed on August 22, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The present disclosure generally relates to systems and methods for communicating between a station (STA) and an access point (AP) or between other communication devices. Background Art

[0004] Over the past few decades, the market for wireless communication devices has grown by several orders of magnitude due to the use of portable devices and the increase in connectivity and data transfer between various devices. Digital switching technology has facilitated the large-scale deployment of inexpensive, easy-to-use wireless communication networks. In addition, improvements in digital and radio frequency (RF) circuit manufacturing and advances in circuit integration and other aspects have made wireless devices smaller, cheaper and more reliable. Wireless communication can be operated according to various standards such as IEEE 802.11x, Bluetooth, Global System for Mobile Communications (GSM), Code Division Multiple Access (CDMA), etc. With the development of higher data processing volume, network density and other changes, newer standards are constantly being developed for adoption, such as from IEEE 802.11n to IEEE 802.11ac, IEEE 802.11ax or IEEE 802.11be. Network devices can operate as client stations (STAs), access points (APs) or mobile APs.

[0005] IEEE 802.11be defines the EMLSR (Enhanced Multi-Link Single Radio) feature for non-AP STAs.This application incorporates by reference the entire contents of US Patent Application Serial No. 18 / 307,438 disclosing the EMLSR feature. Summary of the invention

[0006] In one aspect, the present disclosure provides a first device comprising: a circuit configured to provide a frame to a second device across a connection consisting of one or more links, the first device and the second device being access points, wherein the circuit is configured to provide a transmission opportunity duration on the first link and an opportunity for the second device to switch to the second link.

[0007] In another aspect, the present disclosure provides a first device, comprising: a circuit configured to provide a frame to a second device across a connection consisting of one or more links, wherein the circuit is configured to detect a first frame from an overlapping basic service set on the first link and determine a first duration of a transmission opportunity for the overlapping basic service set, wherein the circuit is configured to perform one or more of the following operations: 1. switching the first device to a second link, and the first device remains on the second link until the duration minus the time for completing the link switching operation from the second link to the first link expires; 2. if a new frame addressed to the first device or a clear-to-send frame addressed to the second device is received within a third duration , then the first device is switched to the second link, and the first device remains on the second link until a second duration expires; 3. if the second link continues to be busy / unavailable for a fourth duration, then the first device is switched back to the first link after switching to the second link; 4. if the second device notifies the first device to switch back to the first link before the expiration of the first duration, then the first device is switched back to the first link after switching to the second link; or 5. if the measured received signal strength (RSSI) of the first frame exceeds a first threshold and the first duration exceeds a second threshold, then the first device is switched to the second link.

[0008] In another aspect, the present disclosure provides a first device comprising: a circuit configured to provide frames across a connection consisting of one or more links to a second device and a third device, the first device being an access point, and the second device and the third device being client devices, wherein the circuit is configured to initiate a frame sequence immediately after obtaining access to a medium on the first link, the frame sequence providing a transmission opportunity duration, wherein the circuit is configured to switch the first device to the second link after the frame sequence, and switch the first device back to the first link no later than when the transmission opportunity duration expires. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Various objects, aspects, features and advantages of the present disclosure will become more apparent and better understood by reference to the detailed description in conjunction with the accompanying drawings, in which like reference numerals identify corresponding elements throughout. In the drawings, like reference numerals generally indicate identical, functionally similar and / or structurally similar elements.

[0010] Figure 1A is a block diagram depicting a network environment including one or more access points in communication with one or more devices or stations in accordance with some embodiments.

[0011] Figure 1B and 1C is a block diagram depicting a computing device useful in conjunction with the methods and systems described herein, according to some embodiments.

[0012] Figure 2 A wireless network is illustrated in accordance with some embodiments.

[0013] Figure 3 According to some embodiments, Figure 2 0036] A general block diagram of an AP or STA of a network illustrated in FIG.

[0014] Figure 4 is a sequence diagram for communicating using a first CLS protocol according to some embodiments.

[0015] Figure 5 is a sequence diagram for communicating using a second CLS protocol according to some embodiments.

[0016] Figure 6 is a sequence diagram for communicating using a third CLS protocol according to some embodiments.

[0017] Figure 7 is a sequence diagram for communicating using the fourth CLS protocol according to some embodiments.

[0018] Figure 8 is a sequence diagram for communicating using the fifth CLS protocol according to some embodiments.

[0019] Fig. 9 is a sequence diagram for communicating using the first CLS protocol or the fifth CLS protocol in a residential mesh network according to some embodiments.

[0020] The details of various embodiments of the methods and systems are set forth in the accompanying drawings and the description below. DETAILED DESCRIPTION

[0021] The following IEEE standards (including any draft versions of such standards) are hereby incorporated by reference herein in their entirety and are made a part of this disclosure for all purposes: WiFi Alliance standards and IEEE 802.11 standards, including but not limited to IEEE 802.11a TM 、IEEE 802.11b TM 、IEEE 802.11be TM 、IEEE 802.11bn TM 、IEEE802.11g TM 、IEEE P802.11n TM ; and IEEE P802.11ac TMAlthough the present disclosure may refer to aspects of these standards, the present disclosure is in no way limited to these standards.

[0022] In order to read the description of the various embodiments below, the following description of the various sections of the specification and their corresponding contents may be helpful:

[0023] - Section A describes a network environment and a computing environment that can be used to practice the embodiments described herein; and

[0024] - Section B describes embodiments of a link switching protocol and methods and apparatus using such a protocol.

[0025] Various client devices may operate as station (STA) devices utilizing multi-link operation using one or more radios (e.g., multi-link single radio (MLSR)). For example, a client device may utilize an MLSR radio for each of various frequency bands (e.g., 2.4 GHz band, 5 GHz band, or 6 GHz band). Various STA devices may operate as APs or non-APs. Non-AP devices are typically clients to AP devices. In some cases, non-AP devices may be configured as mobile APs or portable hotspots, in which case the non-AP devices may support other non-AP devices as their clients. APs / mobile APs and their clients may communicate using one or more radios over multiple links using multi-link operation. Mobile APs may be non-simultaneous transmission-reception (NSTR) devices over a pair of links defined in the 802.11 standard. In addition, as discussed in U.S. patent application serial number 18 / 307,438, an AP or mobile AP may be an EMLSR device over a pair of links. EMLSR APs / mobile APs communicate with their clients over multiple links using EMLSR operation. U.S. Patent Application Serial No. 18 / 307,438 discloses an EMLSR AP / mobile AP that switches links without coordinated support from another EMLSR AP / mobile AP. In some embodiments, multiple EMLSR APs may advantageously coordinate their link switching. Two such client devices may communicate via a non-simultaneous transmission and reception (NSTR) link on one or more links. For example, two clients may operate between 2.4 GHz, 5 GHz, and 6 GHz links. Various devices may coordinate link selection between primary links and non-primary links according to implicit or explicit methods. For example, a single radio may be associated with one or more links so that the single radio may communicate on the selected link and avoid interference on unselected links.

[0026] The network may include an arbitration mechanism or other method to determine a transmission opportunity (TXOP) within a subnetwork, such as a basic service set (BSS) of a device including a client device (e.g., STA) that can communicate via an access point (e.g., AP or mobile AP). However, some networks may include overlapping BSSs (OBSSs). For example, some networks may include overlapping BSSs of the same extended service set (e.g., shared SSID) or different service sets. Some network devices of a BSS may cause interference to one or more OBSSs. A wireless device may perform a clear channel assessment (CCA) before transmission to avoid interfering with other devices. For example, a wireless device may utilize preamble detection (PD) to detect messages of an OBSS (OBSS-PD). Each radio may include a primary link and at least one non-primary link (e.g., a secondary link). The primary link may carry beacon / probe response frames, data frames, and other communications. In response to an OBSS-PD or an OBSS-PD exceeding a threshold, the wireless device may communicate through a non-primary link.

[0027] In some embodiments, enhanced multi-link single radio (EMLSR) operation may involve STAs associated with a multi-link AP (e.g., an AP operating on two or more different links / channels at the same time). The STA may be configured to dynamically switch between links on a per TXOP (transmission opportunity) basis when communicating with the AP. For the next generation 802.11 standard, the extension of the EMLSR feature to the AP ("EMLSR-AP") involves both the AP and its associated STA dynamically switching its operating link from one channel frequency to another channel frequency on a per TXOP basis (e.g., link switching operation). The feature is used by an AP that can only perform full (peak modulation and coding scheme (MCS) / number of spatial streams (Nss) / bandwidth) Tx / Rx operations on one link at a time (e.g., having only a single fully capable radio). The EMLSR-AP may operate according to a protocol (e.g., an implicit link switching (ILS) protocol) to perform autonomous / uncoordinated switching across APs and STAs based on OBSS detection.

[0028] In some embodiments, an enhancement to the implicit link switching (ILS) protocol is provided. The enhancement may include, but is not limited to, additional rules for OBSS detection and threshold-based criteria for link switching (e.g., implicit link switching) operations. In some embodiments, systems and methods relate to coordinated link switching (CLS) operations among devices of the same BSS or different BSSs sharing the same primary link, medium access protocols after link switching operations, CLS use cases for mesh networks, and dual-band AP operations. In some embodiments, CLS operations may refer to link switching operations that use additional data to complete link switching operations. In some embodiments, CLS operations can achieve higher throughput, stronger robustness, and more coordination than uncoordinated ILS operations. According to some embodiments, the link switching protocol for EMLSR-AP operations allows an AP (e.g., a mobile AP) or a STA to explicitly arbitrate an operating link through a control channel.

[0029] In some embodiments, the systems and methods are used in a WiFi environment where an AP and its clients dynamically switch across two different links on a TXOP basis. In some embodiments, an AP supporting EMLSR can operate on one of the two links at any given time (i.e., Tx / Rx). In some embodiments, the two links include: 1. Primary link: In some embodiments, it is used by the AP to transmit periodic beacons, support association / disassociation of clients, and serve clients that do not support link switching operations (such clients always remain on the primary link when communicating with the AP); 2. Non-primary link: It is used by the AP to serve clients that support link switching (each link is on a different channel frequency). In some embodiments, more than two links are used.

[0030] In some embodiments, an AP supporting the CLS protocol together with a subset of its associated clients / STAs can switch between primary and non-primary links on a per-TXOP basis. In some embodiments, the systems and methods as described herein are implemented in an 802.11 AP and non-AP STA chip or an integrated circuit IC disposed in a package.

[0031] In some embodiments, a TXOP may refer to a time interval for transmission on a medium (e.g., a bounded interval in which a QoS-capable station is permitted to transmit a series of frames). In some embodiments, a TXOP constitutes a time period of a sequence of frames switching between an AP and one or more of its clients, separated by an idle time equal to one short interframe space (SIFS). An exemplary TXOP is provided below for an environment including an AP with three associated STAs, where STA1 and STA2 support EMLSR link switching operations, while STA3 does not.

[0032] 1.TXOP 1 (5ms): AP transmits data to STA1 on the primary link;

[0033] 2. TXOP 2 (5 ms): AP and STA2 switch to the non-primary link, AP transmits data to STA2 on the non-primary link, and both devices switch back to the primary link at the end of the TXOP;

[0034] 3.TXOP 3 (3ms): AP transmits data to STA3 on the primary link;

[0035] 4. TXOP 4 (4 ms): AP and STA1 switch to the non-primary link, STA1 transmits data to AP on the non-primary link, and both devices switch back to the primary link at the end of the TXOP;

[0036] In some embodiments, TXOPs are separated in time by a short duration (eg, approximately 100 us) consisting primarily of a SIFS and a backoff delay.

[0037] In some embodiments, systems and methods for ILS, CLS, and OBSS detection operations are provided. The protocols used for such operations may include five CLS protocols, non-primary medium access protocol after link switching, CLS protocol for residential mesh networks, and CLS protocol for dual-band APs.

[0038] In some embodiments, if such a control / link channel exists, each of the AP or STA can detect OBSS communication on the primary link, and can convey information about OBSS communication through the control link / channel. For example, the AP or STA can convey time, size, duration, transmission unit, reception unit, energy, etc. Each of the AP or STA can aggregate its own detected OBSS communication with the detected OBSS communication of the corresponding device. Thereafter, each of the AP or STA can transmit according to the logical AND of the availability of the link relative to both the AP and the STA. For example, if the primary link is available for the transmitter-receiver pair, the AP and STA communicate via the primary link. If the primary main link is not available and the non-primary link is available for the transmitter-receiver pair, the AP and STA can communicate via the non-primary link. If the primary link and any non-primary link are not available for the transmitter-receiver pair, the AP or STA can delay the transmission, transmit through a different frequency band, adjust the link, etc. The control channel / link may include a wired connection or a wireless connection. For example, the control channel / link may include a 2.4GHz link or a 900MHz link.

[0039] According to some embodiments, an AP (e.g., a mobile AP) or a STA may implicitly arbitrate an operating link. An AP (e.g., a mobile AP) or a STA may detect the same or different OBSS communications. For example, location, orientation, OBSS-PD threshold, etc. may cause one wireless device to determine that the primary link is unavailable, and the wireless device may transition to a secondary link. After mutually detecting the same OBSS transmission, the corresponding wireless device may communicate via a non-primary link. Non-mutual detection of OBSS transmissions may result in poor link selection between a transmitting device and a receiving device. For example, one of a transmitter-receiver pair may detect OBSS communication, and the other of a transmitter-receiver pair may not detect OBSS communication, or each of a transmitter-receiver pair may detect different OBSS communications. An AP or STA may perform a CCA or ready to send (RTS) clear to send (CTS) exchange before transmission. For example, a transmission unit may transport an RTS message indicating a ready to send frame. After receiving the RTS, the receiving unit may immediately transport a CTS message. Upon not receiving a CTS within a predetermined amount of time, the transmitter may determine that the receiver or channel is unavailable and schedule a retransmission for a later time, another link, another frequency band, etc.

[0040] In some embodiments, each link of the first wireless frequency band is a wireless link equal to or greater than 20 MHz in the 5 GHz range. Each link of the second wireless frequency band may be equal to or greater than 20 MHz in the 6 GHz range.

[0041] Some embodiments are directed to a first device. The first device includes circuitry configured to provide a frame to a second device across a connection including one or more links. The circuitry is configured to detect a first frame from an overlapping basic service set on a first link and determine a duration of a transmission opportunity for the overlapping basic service set. The circuitry is configured to switch to a second link if a measured received signal strength (RSSI) of the first frame exceeds a first threshold and the duration exceeds a second threshold.

[0042] In some embodiments, an overlapping basic service set may refer to an access point and its associated devices having a coverage area that intersects with another service set. Examples of overlapping basic service sets (OBBS) are described in the 802.11 standard. In some embodiments, received signal strength may refer to a metric used in wireless communications to measure the power level of a signal received by a receiver (e.g., a Wi-Fi access point or wireless device). In some embodiments, received signal strength is an indication of how strong or weak a received radio signal is. A transmission opportunity may refer to a time slot or time period in which a wireless device has the opportunity to transmit data. In wireless networks, data transmission may be regulated by protocols such as carrier sense multiple access with collision avoidance (CSMA / CA). CSMA / CA involves sensing the medium before transmission to avoid collisions. When the medium is idle, the device has a transmission opportunity to send its data. Examples of transmission opportunities are described in the 802.11 standard.

[0043] In some embodiments, frames are provided according to the 802.11 protocol, and a connection is established by using an association or authentication operation. In some embodiments, the circuit is configured to receive a second frame from a second device on a second link during the duration. In some embodiments, the circuit is configured to switch to the first link after the duration. In some embodiments, the circuit is configured to communicate on the first link or the second link using an enhanced multi-link single radio. In some embodiments, the first device and the second device are each one of a station device or an access point. In some embodiments, the first link is a primary link and the second link is a non-primary link. In some embodiments, at least one of the first link and the second link uses a 2.4 GHz frequency band or a 5 GHZ frequency band.

[0044] Some embodiments relate to a first device. The first device includes a circuit configured to provide multi-link operation to a second device across a connection. The circuit is configured to provide a frame to the second device across a connection including one or more links. The circuit is configured to detect a first frame from an overlapping basic service set on the first link and determine a first duration of a transmission opportunity of the overlapping basic service set. The circuit is configured to: 1. switch to a second link, and the first device remains on the second link until the duration minus the time to complete the link switching operation from the second link to the first link expires; 2. if a new frame addressed to the first device or a clear-to-send frame addressed to the second device is received within the second duration, then switch to the second link, and the first device remains on the second link until the second duration expires; 3. if the second link continues to be busy / unavailable for a certain amount of time, then switch back to the primary link; or 4. if the second device notifies the first device to switch back to the primary link before the first duration expires, then switch back to the primary link after switching to the second link. In some embodiments, the link switching operation may refer to changing to a different link for communication purposes. In some embodiments, the clear-to-send frame may refer to the transmission of a frame to avoid conflicts in a shared communication medium. Examples of link switching operations and clear-to-send (CTS) mechanisms are described in the 802.11 standard.

[0045] In some embodiments, the second device is an access point. In some embodiments, the circuit is configured to: 1. switch to the second link, and the first device remains on the second link until the duration minus the time to complete the link switching operation from the second link to the first link expires; 2. if a new frame addressed to the first device or a clear to send frame addressed to the second device is received within the second duration, then switch to the second link, and the first device remains on the second link until the second duration expires; 3. if the second link continues to be busy / unavailable for a certain amount of time, then switch back to the primary link; and 4. if the second device notifies the first device to switch back to the primary link before the first duration expires, then switch back to the primary link after switching to the second link.

[0046] In some embodiments, the circuit is configured to switch to the second link if the measured received signal strength (RSSI) of the first frame exceeds a first threshold and the duration exceeds a second threshold. In some embodiments, the first device is an access point. In some embodiments, the first frame is detected as coming from an overlapping service set using a setting in a physical layer preamble. In some embodiments, the setting is a split number or modulation coding scheme setting that is not supported by the first device. In some embodiments, the circuit is configured to: 1. Keep the first device on the first link if the second device serves a client that supports link switching and the first device serves a client that does not support link switching; 2. If the idle channel assessment status of the first device indicates that the second link is idle / unoccupied, and the idle channel assessment status of the second device indicates that the second link is busy, then switch the first device to the second link; or 3. If the first device expects that the quality of service of the first device will be more improved by switching to the second link than the second device, then switch the first device to the second link.

[0047] In some embodiments, the modulation and coding scheme setting may refer to an indication of how to modulate and / or encode data. In some embodiments, the number of splits may refer to the number of spatial streams or links used to make a connection. Examples of spatial stream protocols, modulation and coding schemes are described in the 802.11 standard.

[0048] In some embodiments, the first device is an access point and the first frame is detected as being from an overlapping service set in response to data in an uplink / downlink field. In some embodiments, the uplink / downlink field may refer to a portion of a frame that indicates the direction in which the frame is communicated (e.g., whether the frame is provided from an access point to a station or from a station to an access point). Examples of uplink / downlink fields are described in the 802.11 standard.

[0049] Some embodiments relate to a circuit configured to provide a frame to a second device across a connection including one or more links. The first device and the second device are access points. The circuit is configured to provide a transmission opportunity duration for the first device on the first link and provide the second device with an opportunity to switch to the second link.

[0050] In some embodiments, the circuit is configured to: if the second device serves a client that supports link switching operations and the first device serves a client that does not support link switching operations, then keep the first device on the first link. In some embodiments, supporting link switching operations may refer to the ability of the device to perform link switching operations. Link switching operations may be performed according to the protocol discussed below. In some embodiments, idle / unoccupied may refer to a condition in which a link can be used for communication. The clear channel assessment status may refer to data in a frame indicating that a link is idle / unoccupied or busy. Examples of clear channel assessment mechanisms are described in the 802.11 standard.

[0051] In some embodiments, the circuit is configured to switch the first device to the second link if the first device expects that the quality of service of the first device will be improved more by switching to the second link than the second device.In some embodiments, quality of service may refer to a level of connection quality in the form of a performance metric.

[0052] In some embodiments, the circuit is configured to transmit a trigger on the second link addressed to at least one client device having listen-only capability on the second link. The trigger is used to cause the client device to switch to receive and transmit capability. In some embodiments, the trigger may refer to a message or frame used to cause an action. In some embodiments, the listen-only capability may refer to the ability to receive but not transmit.

[0053] Some embodiments relate to a first device that includes circuitry configured to provide frames to a second device and a third device across a connection consisting of one or more links. The first device is an access point, and the second device and the third device are client devices. The circuitry is configured to initiate a sequence of frames upon obtaining access to a medium on a first link. The sequence of frames provides a transmission opportunity duration and notifies the second device and the third device to move to a second link. The circuitry is configured to switch the first device back to the first link no later than when the transmission opportunity duration expires.

[0054] The circuit is configured to transmit a trigger on the second link addressed to at least one client device with listen-only capability on the second link. The trigger causes the at least one client device with listen-only capability to switch to full receive and transmit capability on the second link.

[0055] In some embodiments, the fourth device is an access point. The first device is configured to receive a notification from the fourth device to switch the first device to the second link, and the fourth device remains on the first link. In some embodiments, the fourth device is an access point, and the first device is configured to provide a notification to the fourth device to switch the first device to the second link. The fourth device remains on the first link, and the notification allows the fourth device to utilize the first link for a duration that does not exceed or exactly matches the transmission opportunity duration.

[0056] Some embodiments are directed to a first device. The first device includes circuitry configured to provide a frame to a second device across a connection consisting of one or more links. The circuitry is configured to detect a first frame from an overlapping basic service set on a first link and determine a first duration of a transmission opportunity for the overlapping basic service set. The circuit is configured to perform one or more of the following operations: 1. Switch the first device to the second link, and the first device remains on the second link until a duration minus the time to complete the link switching operation from the second link to the first link expires; 2. If a new frame addressed to the first device or a clear-to-send frame addressed to the second device is received within a third duration, then switch the first device to the second link, and the first device remains on the second link until the second duration expires; 3. If the second link continues to be busy / unavailable within a fourth duration, then switch the first device back to the first link after switching to the second link; 4. If the second device notifies the first device to switch back to the first link before the first duration expires, then switch the first device back to the first link after switching to the second link; or 5. If the measured received signal strength (RSSI) of the first frame exceeds a first threshold and the first duration exceeds a second threshold, then switch the first device to the second link.

[0057] In some embodiments, the circuit is configured to provide a frame to the third device across the connection. The circuit is configured to detect a first frame from an overlapping basic service set on the first link and determine a second transmission opportunity duration of the overlapping basic service set. The circuit is configured to switch the first device to the second link or the third link if a received signal strength of the first frame exceeds a first threshold and the second transmission opportunity duration exceeds a second threshold.

[0058] In some embodiments, the frame is provided according to the 802.11 protocol. In some embodiments, the circuit is configured to receive the second frame from the third device on the second link or the third link or transmit the third frame to the third device during the second transmission opportunity duration. In some embodiments, the circuit is configured to switch the first device back to the first link no later than when the second transmission opportunity duration expires.

[0059] Some embodiments relate to a first device. The first device includes circuitry configured to provide frames to a second device and a third device across a connection consisting of one or more links. The first device is an access point, and the second device and the third device are client devices. The circuitry is configured to initiate a sequence of frames upon obtaining access to a medium on the first link. The sequence of frames provides a transmission opportunity duration, and the circuitry is configured to switch the first device to the second link after the sequence of frames, and switch the first device back to the first link before the transmission opportunity duration expires.

[0060] Some embodiments are directed to a first device. The first device includes circuitry configured to provide a frame to a second device across a connection consisting of one or more links. The circuitry is configured to detect a first frame from an overlapping basic service set on a first link and determine a first duration of a transmission opportunity for the overlapping basic service set. The circuit is configured to perform one or more of the following operations: 1. Switch the first device to the second link, and the first device remains on the second link until a duration minus the time to complete the link switching operation from the second link to the first link expires; 2. If a new frame addressed to the first device or a clear-to-send frame addressed to the second device is received within a third duration, then switch the first device to the second link, and the first device remains on the second link until the second duration expires; 3. If the second link continues to be busy / unavailable within a fourth duration, then switch the first device back to the first link after switching to the second link; 4. If the second device notifies the first device to switch back to the first link before the first duration expires, then switch the first device back to the first link after switching to the second link; or 5. If the measured received signal strength (RSSI) of the first frame exceeds a first threshold and the first duration exceeds a second threshold, then switch the first device to the second link.

[0061] A. Computing and Network Environment

[0062] Before discussing specific embodiments of the present solution, it may be helpful to describe aspects of the operating environment and associated system components (eg, hardware elements) in conjunction with the methods and systems described herein. Figure 1A , depicts an embodiment of a network environment. Briefly, the network environment includes a wireless communication system that includes one or more access points (APs) or network devices 106, one or more stations or wireless communication devices 102, and network hardware components or network hardware 192. The wireless communication device 102 may, for example, include a laptop computer, a tablet computer, a personal computer, and / or a cellular telephone device. Figure 1B and 1CThe details of the embodiments of each station or wireless communication device 102 and AP or network device 106 are described in more detail. In one embodiment, the network environment may be an ad hoc network environment, an infrastructure wireless network environment, a subnet environment, etc. The network device 106 or AP may be operably coupled to the network hardware 192 via a local area network connection. In some embodiments, the network device 106 is a 5G base station. The network hardware 192, which may include routers, gateways, switches, bridges, modems, system controllers, appliances, etc., may provide a local area network connection for the communication system. Each of the network devices 106 or APs may have an associated antenna or antenna array to communicate with the wireless communication devices in its area. The wireless communication device 102 may register with a specific network device 106 or AP to receive services from the communication system (e.g., via SU-MIMO or MU-MIMO configuration). For direct connections (e.g., point-to-point communications), some wireless communication devices may communicate directly via allocated channels and communication protocols. Some of the wireless communication devices 102 may be moving or relatively stationary relative to the network device 106 or AP.

[0063] In some embodiments, the network device 106 or AP includes a device or module (including a combination of hardware and software) that allows the wireless communication device 102 to connect to a wired network using wireless fidelity (WiFi) or other standards. The network device 106 or AP may sometimes be referred to as a wireless access point (WAP). The network device 106 or AP may be implemented (e.g., configured, designed and / or constructed) for operation in a wireless local area network (WLAN). In some embodiments, the network device 106 or AP may be connected to a router (e.g., via a wired network) as a standalone device. In other embodiments, the network device 106 or AP may be a component of a router. The network device 106 or AP may provide access to a network to multiple devices. The network device 106 or AP may, for example, be connected to a wired Ethernet connection and use a radio frequency link to provide a wireless connection for other devices 102 to utilize that wired connection. The network device 106 or AP may be implemented to support standards that use one or more radio frequencies to send and receive data. Those standards and the frequencies they use may be defined by IEEE (e.g., IEEE 802.11 standards). The network device 106 or AP may be configured and / or used to support public Internet hotspots and / or extend the Wi-Fi signal range of the network over the network.

[0064] In some embodiments, the access point or network device 106 may be used for a wireless network (e.g., IEEE 802.11, Bluetooth, ZigBee, any other type of radio frequency based network protocol and / or variants thereof) (e.g., in a home, in a vehicle, or in a building). Each of the wireless communication devices 102 may include a built-in radio and / or be coupled to a radio. Such wireless communication devices 102 and / or access points or network devices 106 may operate in accordance with various aspects of the present disclosure as presented herein to enhance performance, reduce cost and / or reduce size and / or enhance broadband applications. Each wireless communication device 102 may have the ability to act as a client node that seeks access to resources (e.g., data and connections to networked nodes such as servers) via one or more access points or network devices 106.

[0065] The network connection may include any type and / or form of network, and may include any of the following: a point-to-point network, a broadcast network, a telecommunications network, a data communications network, a computer network. The network topology may be a bus, a star, or a ring network topology. The network may be any such network topology as known to those skilled in the art that is capable of supporting the operations described herein. In some embodiments, different types of data may be transmitted via different protocols. In other embodiments, the same type of data may be transmitted via different protocols.

[0066] The communication device 102 and the access point or network device 106 may be deployed as and / or executed on any type and form of computing device, such as a computer, network device, or appliance capable of communicating over any type and form of network and performing the operations described herein. Figure 1B and 1C A block diagram of a computing device 100 is depicted for practicing an embodiment of a wireless communication device 102 or a network device 106. Figure 1B and 1C As shown in FIG. 1 , each computing device 100 includes a processor 121 (eg, a central processing unit) and a main memory unit 122. Figure 1B As shown in FIG. 1 , computing device 100 may include storage device 128, installation device 116, network interface 118, I / O controller 123, display devices 124a to 124n, keyboard 126, and pointing device 127 such as a mouse. Storage device 128 may include an operating system and / or software. Figure 1C As shown in , each computing device 100 may also include additional optional elements, such as a memory port 103, a bridge 170, one or more input / output devices 130a to 130n, and a cache memory 140 that communicates with a central processing unit or processor 121.

[0067] The central processing unit or processor 121 is any logic circuitry that responds to and processes instructions fetched from the main memory unit 122. In many embodiments, the central processing unit or processor 121 is provided by a microprocessor unit, such as those manufactured by Intel Corporation of Santa Clara, California; those manufactured by International Business Machines of White Plains, New York; or those manufactured by Advanced Micro Devices of Sunnyvale, California. The computing device 100 may be based on any of these processors, or any other processor capable of operating as described herein.

[0068] The main memory unit 122 may be one or more memory chips capable of storing data and allowing direct access to any storage location by the microprocessor or processor 121, such as any type or variant of static random access memory (SRAM), dynamic random access memory (DRAM), ferroelectric RAM (FRAM), NAND flash memory, NOR flash memory, and solid state drive (SSD). The main memory unit 122 may be based on any of the memory chips described above, or any other available memory chip capable of operating as described herein. Figure 1B In the embodiment shown in FIG. 1 , processor 121 communicates with main memory unit 122 via system bus 150 (described in more detail below). Figure 1C An embodiment of computing device 100 is depicted in which the processor communicates directly with main memory unit 122 via memory port 103. For example, in Figure 1C In the embodiment, the main memory unit 122 may be a DRDRAM.

[0069] Figure 1C An embodiment is depicted in which the main processor 121 communicates directly with the cache memory 140 via a secondary bus (sometimes referred to as a backside bus). In other embodiments, the main processor 121 communicates with the cache memory 140 using the system bus 150. The cache memory 140 typically has a faster response time than the main memory unit 122 and is provided by, for example, SRAM, BSRAM, or EDRAM. Figure 1C, the processor 121 communicates with various I / O devices 130 via a local system bus 150. Various buses may be used to connect the central processing unit or processor 121 to any I / O device 130, such as a VESA VL bus, an ISA bus, an EISA bus, a Micro Channel Architecture (MCA) bus, a PCI bus, a PCI-X bus, a PCI-Express bus, or a NuBus. For embodiments in which the I / O device is a video display 124, the processor 121 may communicate with the display 124 using an Advanced Graphics Port (AGP). Figure 1C An embodiment of a computer or computer system 100 is depicted in which the main processor 121 can communicate directly with the I / O device 130b, such as via HYPERTRANSPORT, RAPIDIO, or INFINIBAND communication technology. Figure 1C Also depicted is an embodiment in which a local bus is mixed with direct communications: processor 121 communicates with I / O device 130a using a local interconnect bus while communicating directly with I / O device 130b.

[0070] A variety of I / O devices 130a to 130n may be present in computing device 100. Input devices include keyboards, mice, trackpads, trackballs, microphones, dials, touchpads, touch screens, and drawing tablets. Output devices include video displays, speakers, inkjet printers, laser printers, projectors, and dye sublimation printers. I / O devices may be controlled by I / O controller 123, such as Figure 1B 100. The I / O controller may control one or more I / O devices, such as a keyboard 126 and a pointing device 127, e.g., a mouse or optical pen. In addition, the I / O devices may also provide storage and / or installation media for the computing device 100. In still other embodiments, the computing device 100 may provide a USB connection (not shown) to receive a handheld USB storage device, such as the USB flash drive family of devices manufactured by Twintech Industry, Inc. of Los Alamitos, California.

[0071] Reference again Figure 1B, the computing device 100 may support any suitable installation device 116, such as a disk drive, a CD-ROM drive, a CD-R / RW drive, a DVD-ROM drive, a flash memory drive, a tape drive in various formats, a USB device, a hard drive, a network interface, or any other device suitable for installing software and programs. The computing device 100 may further include a storage device, such as one or more hard drives or a redundant array of independent disks, for storing an operating system and other related software and for storing application software programs, such as any program or software 120 for implementing (e.g., configured and / or designed for) the systems and methods described herein. Optionally, any of the installation devices 116 may also be used as a storage device. In addition, the operating system and software may be run from a bootable medium.

[0072] In addition, the computing device 100 may include a network interface 118 to interface with a network through various connections, including but not limited to a standard telephone line, a LAN or WAN link (e.g., 802.11, T1, T3, 56kb, X.25, SNA, DECNET), a broadband connection (e.g., ISDN, Frame Relay, ATM, Gigabit Ethernet, Ethernet over SONET), a wireless connection, or some combination of any or all of the above. The connection may be established using various communication protocols (e.g., TCP / IP, IPX, SPX, NetBIOS, Ethernet, ARCNET, SONET, SDH, Fiber Distributed Data Interface (FDDI), RS232, IEEE 802.11, IEEE 802.11a, IEEE 802.11b, IEEE 802.11g, IEEE 802.11n, IEEE 802.11ac, IEEE 802.11ad, CDMA, GSM, WiMax, and direct asynchronous connection). In one embodiment, computing device 100 communicates with other computing devices 100' via any type and / or form of gateway or tunneling protocol, such as Secure Sockets Layer (SSL) or Transport Layer Security (TLS). Network interface 118 may include a built-in network adapter, a network interface card, a PCMCIA network card, a card bus network adapter, a wireless network adapter, a USB network adapter, a modem, or any other device suitable for connecting computing device 100 to any type of network capable of communicating and performing the operations described herein.

[0073] In some embodiments, the computing device 100 may include or be connected to one or more display devices 124a to 124n. In this way, any of the I / O devices 130a to 130n and / or the I / O controller 123 may include any type and / or form of suitable hardware, software, or a combination of hardware and software to support, implement, or provide the connection and use of the display devices 124a to 124n by the computing device 100. For example, the computing device 100 may include any type and / or form of video adapter, video card, driver, and / or library to interface, communicate, connect, or otherwise use the display devices 124a to 124n. In one embodiment, the video adapter may include multiple connectors to interface to the display devices 124a to 124n. In other embodiments, the computing device 100 may include multiple video adapters, each of which is connected to the display devices 124a to 124n. In some embodiments, any part of the operating system of the computing device 100 may be configured for use with multiple display devices 124a to 124n. In other embodiments, the I / O device 130 can be a bridge between the system bus 150 and an external communication bus, such as a USB bus, an Apple Desktop bus, an RS-232 serial connection, a SCSI bus, a FireWire bus, a FireWire 800 bus, an Ethernet bus, an AppleTalk bus, a Gigabit Ethernet bus, an asynchronous transfer mode bus, a Fibre Channel bus, a fiber optic bus, a serial attached small computer system interface bus, a USB connection, or an HDMI bus.

[0074] Figure 1B and 1CA computing device 100 of the type depicted in the drawings may operate under the control of an operating system that controls the scheduling of tasks and access to system resources. The computing device 100 may run any operating system, such as any of versions of the MICROSOFT WINDOWS operating system, different distributions of the Unix and Linux operating systems, any version of the MAC OS for Macintosh computers, any embedded operating system, any real-time operating system, any open source operating system, any proprietary operating system, any operating system for mobile computing devices, or any other operating system capable of running on a computing device and performing the operations described herein. Typical operating systems include, but are not limited to: Android, which is produced by Google Inc.; WINDOWS 7, 8 and 10, which are produced by Microsoft Corporation of Redmond, Washington; MAC OS, which is produced by Apple Computer of Cupertino, California; WebOS, which is produced by Research In Motion (RIM); OS / 2, which is produced by International Business Machines of Armonk, New York; and Linux, which is a freely available operating system distributed by Caldera Corp. of Salt Lake City, Utah, or any type and / or form of Unix operating system, etc.

[0075] The computer system or computing device 100 may be any workstation, phone, desktop computer, laptop or notebook computer, server, handheld computer, mobile phone or other portable telecommunication device, media playback device, gaming system, mobile computing device, or any other type and / or form of computing, telecommunication or media device capable of communication. In some embodiments, the computing device 100 may have different processors, operating systems, and input devices consistent with the device. For example, in one embodiment, the computing device 100 is a smart phone, mobile device, tablet computer, or personal digital assistant. Moreover, the computing device 100 may be any workstation, desktop computer, laptop or notebook computer, server, handheld computer, mobile phone, any other computer, or other form of computing or telecommunication device capable of communication and having sufficient processor power and memory capacity to perform the operations described herein.

[0076] Aspects of the operating environment and components described above will become apparent in the context of the systems and methods disclosed herein.

[0077] B. Station and AP communication

[0078] Disclosed herein are systems and methods for enhanced multi-link single radio operation. For example, an AP (e.g., a mobile AP) may utilize a radio that transmits or receives frames for two or more links. A multi-link radio may alternate between one or more links to improve performance relative to single-link operation. For example, the same radio may be associated with a primary link and a secondary link so that the radio may alternate between communications through the link in response to network or device availability. A secondary link may be referred to as a non-primary link. Such a device may limit crosstalk between radios relative to simultaneous transmission / reception devices. According to some embodiments, a radio device may send or receive control channel / link communications to coordinate active links of a primary link or a secondary link. According to some embodiments, a radio may determine a primary link or a secondary link based on detected messages or other network node behaviors via CLS operations. In some embodiments, the system and method may be used in conjunction with a device having a fully capable radio that alternates between two links for transmission / reception purposes. In some embodiments, the system and method may be used in conjunction with a device having another lower-capability scanning radio that facilitates assessment of channel availability. In some embodiments, the access points may each use a second link, where the second link of a first access point is different from the second link of a second access point (eg, the second links may occupy different channel frequencies, may partially overlap in frequency, and may have different bandwidths).

[0079] In some embodiments, a STA may refer to any device for communicating in a communication system, and includes, but is not limited to, a fixed, portable, or mobile laptop, a desktop personal computer, a personal digital assistant, an access point, a workstation, a wearable device, a smart phone, or a Wi-Fi phone. In some embodiments, an access point (AP) may refer to a device for communicatively coupling one or more non-AP devices (e.g., clients or client devices) to a network. More specifically, an AP may enable non-AP devices to connect and communicate with a network. In some embodiments, an AP may be a wireless access point (WAP) configured to enable wireless communication between non-AP devices. APs include, but are not limited to, mobile, portable, or fixed hotspots, routers, bridges, or other communication devices.

[0080] In some embodiments, a radio may refer to a device for wirelessly communicating data. In some embodiments, a frequency band may refer to a predefined portion of a wireless spectrum. For example, a wireless frequency band may include a continuous spectrum according to a standard such as 5030-5990 MHz, 5945-7125 MHz, 2401-2495 MHz, etc. A link may refer to a subdivision of a frequency band used for wireless communication between radios or another channel for communication, such as a wired link (e.g., Ethernet) for communication. The link may include a frequency subdivision, a time subdivision, a combination thereof, and the like. A multi-link single radio (MLSR) may refer to a radio configured to selectively operate through at least two links (e.g., two links of at least one frequency band). For example, an MLSR radio may operate through a link in response to wireless spectrum congestion, or increase throughput by alternating transmission or reception therebetween. For example, an MLSR may operate through a primary link, a secondary link, and the like. In some embodiments, a primary link may refer to a default, initial, or first link available to a device, such as a device including an MLSR radio. In some embodiments, a secondary link may refer to a non-default, alternative, or second link available to a device, such as a device comprising an MLSR radio. In some embodiments, overlapping base station set (OBSS) communications may refer to communications transmitted or received by a device of a first basic service set that are detected by a device of a second basic service set. In some embodiments, simultaneous monitoring (e.g., of a band or link) may refer to a radio monitoring multiple bands or links so that the presence or content of a wireless message on any band or link can be detected. In some embodiments, the content of a message may refer to information in a message body, a message header, a message preamble, and the like.

[0081] Figure 2 3 is a network diagram 300 of a BSS 305 according to some embodiments. The BSS 305 may include an AP 310 (e.g., a mobile AP 310) and one or more STAs (e.g., non-APs). For example, the BSS 305 may include a first STA 315, a second STA 320, and a third STA 322. The AP 312 may also operate near the BSS 305. Various devices of the BSS 305 and the AP 312 may detect OBSS communications of one or more OBSSs based on their location, gain, or other characteristics. For example, the AP 310 may detect OBSS communications from the first OBSS, or the first STA 315 may detect OBSS communications from the second OBSS. One or more sideband links may interconnect the various devices of the BSS 305. For example, the sideband links may be different wireless links on the same or different wireless frequency bands (e.g., the 2.4 GHz band) of the same wireless network. In some embodiments, various devices of BSS 305 are configured for use with the CLS protocol, as described below.

[0082] The first OBSS or the second OBSS may include various AP or STA devices. OBSS communications may include uplink transmissions, downlink transmissions, broadcast messages, ad hoc messages, etc. BSS 305 may include primary links and secondary links of a frequency band of a wireless network. Figures 4 to 8 In the discussion of , for sequence diagrams, Figure 2 The various elements of are referred to as examples of wireless networks. Such references are merely to provide exemplary embodiments and are not intended to be limiting. For example, the various networks may include additional, fewer, or different devices, sideband links (e.g., wired or wireless links), etc. For example, some embodiments may utilize sideband communications between BSS 305 and various OBSSs. In addition, some OBSSs may be detected by AP 310 and STAs 315, 320, and 322 communicating therewith. For example, AP 310 and STAs 315, 320, and 322 may transition to secondary links and continue communicating.

[0083] refer to Figure 3 According to some embodiments, the device 221 is one of the AP 310 or 312 or the STAs 315, 320, and 322 ( Figure 2 ), and is configured for protocols and operations as described below. In some embodiments, device 221 includes processing circuitry 233, link switching module 239, and OBSS detection module 243. In some embodiments, processing circuitry 233 is any circuit system or component that can perform logic and communication processing operations, and may include processor 235 and memory 237.

[0084] In some embodiments, the processing circuit 233 is implemented as a field programmable gate array, an application specific integrated circuit, hardware, a software execution processor, or a state machine. In some embodiments, the processing circuit 233 is part of a layer (e.g., MAC layer, network, PHY layer) of an IEEE 802.11 standard device. In some embodiments, the processing circuit 233 can be configured to perform communication operations, frame construction and processing, discovery operations, association operations, authorization operations, connection setup, disassociation operations, handover operations, OBSS detection operations, ILS operations, CLS operations, and deauthentication operations. In some embodiments, instructions for the processing circuit 233 are stored in a non-transitory medium such as a memory 237.

[0085] The memory 237 may be one or more devices (e.g., RAM, ROM, flash memory, hard disk storage device) for storing data and / or computer code, which are used to complete and / or facilitate the various processes described herein. The memory 237 may be or include non-transitory volatile memory, non-volatile memory, and non-transitory computer storage media. The memory 237 may include database components, object code components, script components, or any other type of information structure for supporting the various activities and information structures described herein. The memory 237 may be communicatively coupled to the processor 235 and include computer code or instructions for executing one or more processes described herein. The processor 235 may be implemented as one or more application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), a group processing component, a software execution processor, a state machine, or other suitable electronic processing components. In this way, the AP or network device 106 ( Figure 1A ) is configured to execute various modules and / or programs and store associated data in a database in memory 237. Modules (e.g., modules 239 and 243) may be implemented in AP software (e.g., MAC layer or PHY layer software) or STA software (e.g., MAC layer or PHY layer software). In some embodiments, AP 310 or STA 315 ( Figure 2 ) is structured and used to establish connections and to other computing systems and devices (e.g., wireless communication device 102, network hardware 192, other access points or network devices 106) via a network (e.g., a WAN connection, a LAN connection, a WLAN connection, etc.). Figures 1A to 1C ))’s access for handover.

[0086] The link switching module 239 and the OBSS detection module 243 may be configured to provide OBSS detection and link switching (e.g., CLS and ILS) operations. For example, in the network of the network diagram 300, the AP 310 and its clients or STAs 315, 320, and 322 are located on a primary link that is time-shared with the OBSS. The OBSS detection module 243 detects the OBSS frame and determines the duration of the OBSS TXOP. In some embodiments, if both the measured received signal strength (RSSI) of the OBSS frame and the OBSS TXOP duration exceed some predetermined thresholds, then the link switching module 239 switches the AP to a non-primary link. In some embodiments, any client or STA of an AP supporting EMLSR may detect the same OBSS frame, determine the TXOP duration, and if both the measured RSSI and TXOP duration of the OBSS frame exceed a predetermined threshold negotiated with the AP, then also switch to a non-primary link. The threshold may be fixed, programmable, or adaptive. In some embodiments, the threshold is set based on medium characteristics. In some embodiments, the threshold is set during association or initiation. In some embodiments, the threshold is selected from an acceptable threshold range. In some embodiments, the AP and client or STA communicate over the non-primary link immediately after obtaining medium access, and switch back to the primary link before the OBSS TXOP expires. In some embodiments, the link switching operation may occur without detecting any OBSS frames (e.g., without information about the RSSI or TXOP duration of any OBSS frames). For example, some CLS protocols may cause a link switch without detecting OBSS.

[0087] In some embodiments, the OBSS detection module 243 may be configured to operate according to one or more rules (defined by the standard, or defined by each negotiation between the AP and the client) for detecting OBSS traffic under the ILS protocol or the CLS protocol. The rules may include, but are not limited to, one or more of the following:

[0088] 1. For OBSS frames in any physical protocol data unit (PPDU) (non-HT / HT / VHT / HE / EHT / EHT+) format, for example: a.) OBSS detection occurs in response to a MAC header indicating different BSSs to which the AP and client or STA belong; and b.) OBSS detection occurs in response to any setting in the PHY preamble that the AP indicates the BSS as a whole does not support (i.e., neither the AP nor the client supports) (e.g., Nss or MCS or BW fields containing certain values ​​for a given physical protocol data unit (PPDU) type (HT / VHT / HE / EHT / EHT+)), unsupported PHY version, etc. As a specific case in some embodiments, this rule may be limited to any setting in the PHY preamble that the AP indicates itself does not support in both Tx and Rx (e.g., Nss or MCS exceeding the maximum value supported by the AP for Tx and Rx, etc.). EHT+ refers to any future 802.11 amendment defined after 802.11be, which may include non-HT / HT / VHT / HE / EHT operation.

[0089] 2. For OBSS frames in VHT-PPDU format: OBSS detection occurs in response to the partial Association Identifier (AID) subfield of the VHT-SIGA field in the PHY preamble indicating a different BSS.

[0090] 3. For OBSS frames in HE / EHT / EHT+PPDU format: OBSS detection occurs in response to the BSS color subfield of the HE-SIGA field (for HE PPDU) or the U-SIG field (for EHT / EHT+PPDU) in the PHY preamble indicating a different BSS. If the AP detects a HE / EHT / EHT+ preamble with a BSS color matching its own BSS color, but with a UL / DL field indicating a downlink (DL) PPDU, the OBSS detection module 243 may interpret the PPDU as an OBSS.

[0091] In some embodiments, the OBSS detection module 243 may be configured to determine the OBSS TXOP duration using the ILS protocol (via the standard, or per negotiation between the AP and the client). In some embodiments, the OBSS TXOP duration is determined using certain information in some embodiments (e.g., in the OBSS frame). The information may include, but is not limited to: 1. The duration signaled in the Duration / ID field of the MAC header of the OBSS frame; 2. The length subfield of the old-style SIG (L-SIG) field in the PHY preamble of the received OBSS frame; 3. For OBSS frames in HE PPDU format, the TXOP duration signaled in the HE-SIGA field of the PHY preamble; and / or 4. For OBSS frames in EHT / EHT+PPDU format, the TXOP duration signaled in the U-SIG field of the PHY preamble. Upon detecting an OBSS frame and determining the duration of the OBSS TXOP, if both the measured received signal strength (RSSI) of the OBSS frame and the OBSS TXOP duration exceed some predetermined thresholds, the AP immediately switches to the non-primary link. In some embodiments, if both the measured RSSI and the TXOP duration of the OBSS frame exceed a predetermined threshold negotiated with the AP, any client of the AP that supports EMLSR and can detect the same OBSS frame and determine its TXOP duration also switches to the non-primary link. In some embodiments, the AP and the client communicate over the non-primary link immediately after obtaining medium access, and switch back to the primary link before the OBSS TXOP expires.

[0092] Figure 4 is according to some embodiments according to the first CLS protocol at AP 310 (eg, Figure 2315 (e.g., non-AP) and STA2 325, all located on the primary link. Upon obtaining access to the medium on the primary link, the AP immediately initiates a frame sequence 402 (comprising one or more frames) which informs the AP of the intended TXOP duration and may additionally notify a subset of the AP's clients STA1 and STA2 to move to the non-primary link. The AP may also notify all of the AP's clients not to attempt any uplink transmission on the primary node within the TXOP duration 404. The frame sequence 402 may include, for example, one or more of the following: a management frame (e.g., an action frame), an A control field within a data frame, and / or a control frame. After the frame sequence 402, the AP and the notified clients or STAs in the AP's client subset all switch to the non-primary link to initiate the next TXOP. In some embodiments, the frame sequence 408 may be set on a non-primary link and include a transmission MU RTS frame, a reception MU RTS frame, a reception CTS frame, a transmission RTS frame, a data frame, a reception block acknowledgement (B-ACK) frame, and a B-ACK frame. The subset may include any number (e.g., 0 to N) or all STAs in the BSS. Any TXOP on a non-primary link is subject to a medium access protocol (e.g., a non-primary medium access protocol after link switching described below). Any TXOP on a non-primary link may be initiated only by an AP (e.g., AP 310), or may also be initiated by a client (e.g., STA1 315 and STA2 320), subject to prior negotiation. In some embodiments, the AP and all clients on the non-primary link switch back to the primary link no later than the expiration of the TXOP duration specified by the AP in the frame sequence. In some embodiments, a non-primary link may refer to a link that is not a primary link (e.g., a secondary link). In some embodiments, any client associated with the AP may access the primary link before the AP accesses the primary link, in which case the client may yield part or all of its TXOP to the AP in order to initiate the above frame sequence 402. The client or STA may transmit a frame that explicitly signals that the TXOP is being handed over to the AP to generate part or all of its TXOP.

[0093] The decision of when to switch back to the primary link may be based on one or more of the following (either via negotiation / agreement prior to this TXOP, or via signaling during the TXOP): 1. A client that has moved to a non-primary link may need to remain on the non-primary link until the TXOP duration 404 signaled in the frame sequence 402 minus the time required to complete the link switching operation from the non-primary link to the primary link expires; 2. If the client is in triggered operation (MU-EDCA) mode on the non-primary link and has not received a frame for a predetermined duration from the end of the last such frame on the non-primary link, the client may need to remain on the non-primary link until the TXOP duration 404 signaled in the frame sequence 402 minus the time required to complete the link switching operation from the non-primary link to the primary link expires; 3. If the client is in triggered operation (MU-EDCA) mode on the non-primary link and has not received a frame for a predetermined duration from the end of the last such frame on the non-primary link, the client may need to remain on the non-primary link until the TXOP duration 404 signaled in the frame sequence 402 minus the time required to complete the link switching operation from the non-primary link to the primary link expires; 4. If the client is in triggered operation (MU-EDCA) mode on the non-primary link and has not received a frame for a predetermined duration from the end of the last such frame on the non-primary link, the client may need to remain on the non-primary link until the TXOP duration 404 signaled in the frame sequence 402 minus the time required to complete the link switching operation from the non-primary link to the primary link expires; 5. If the client is in triggered operation (MU-EDCA) mode on the non-primary link, the client may need to remain on the non-primary link until the TXOP duration 404 signaled in the frame sequence 402 minus the time required to complete the link switching operation 1. If the AP or client on the non-primary link receives a new frame addressed to it or a CTS frame addressed to the AP, the client may switch back to the primary link; 2. If the AP or client on the non-primary link finds that the medium is continuously busy / unavailable to its BSS for an amount of time exceeding a pre-defined threshold, the AP or client may switch back to the primary link; and / or 4. The AP may explicitly notify the clients on the non-primary link to switch back to the primary link before the TXOP expires (for example, if the AP determines that certain QoS metrics (such as data rate or latency) on the non-primary link have dropped below a pre-defined threshold), in which case all devices need to switch back to the primary link.

[0094] Figure 5 is a method according to some embodiments of the present invention for performing a communication between AP1 310 and AP2 312 (all located on the same primary link) according to a second CLS protocol. Figure 2 ) are shown in Figure 1. After gaining access to the medium on the primary link, AP1 immediately initiates a frame exchange 502 with AP2, wherein AP1 signals its intended TXOP duration 504 on the primary link (e.g., for frame exchange 506), and AP1 signals that it is granting AP2 the right to initiate the first CLS protocol described above for switching to the non-primary link ( Figure 4). In response, AP2 rebroadcasts the remaining duration of AP1's TXOP on the primary link (e.g., frame exchange 504), and may additionally initiate the first CLS protocol described above (for frame exchange 508) to switch to a non-primary link whose TXOP duration is no greater than the duration specified by the above-mentioned AP1. The above-mentioned frame exchanges 502, 506 and 508 may utilize, for example, one or more of the following: management frames (e.g., action frames), A control fields within data frames, and / or control frames. Frame exchange 508 may be similar to sequence 408. After the above-mentioned frame exchange, AP1 uses the remaining portion of its TXOP in frame exchange 506 to serve its clients on the primary link. In some embodiments, any client associated with AP1 may obtain access to the primary link before AP1. In this case, the client may give up part or all of its TXOP to AP1 to initiate the second CLS protocol (e.g., by transmitting a frame that explicitly signals that the TXOP is being handed over to AP1).

[0095] Figure 6 is a method according to some embodiments of the present invention for performing a communication between AP1 310 and AP2 312 (all located on the same primary link) according to a third CLS protocol. Figure 2 ) are an exemplary sequence diagram for communicating between. Upon gaining access to the medium on the primary link, AP1 immediately initiates a frame sequence or exchange 602 that initiates a first CLS protocol ( Figure 4 ) to switch AP1 and its subset of clients to the non-primary link for frame exchange 408, and signaling the total TXOP duration of the primary link 604, which includes the intended TXOP duration of AP1 on the non-primary link. Under one of the following conditions, the frame sequence performs a TXOP handover to AP2, thereby granting AP2 the opportunity to serve its clients on the primary link:

[0096] 1. Condition 1: AP2 is allowed to use the primary link for the duration of the frame exchange 606 that does not exceed (i.e., is less than or equal to) the TXOP duration 604 signaled above by AP1 (which may require AP1 to reacquire the medium when switching back to the primary link (e.g., by applying the second rule in the non-primary medium access link post-switching protocol described below on the primary link)); or

[0097] 2. Condition 2: AP2 is required to utilize the primary link for a duration that exactly matches the TXOP duration 604 signaled by AP1 in the frame sequence (this allows AP1 to maintain medium synchronization when switching back to the primary link at the end of the TXOP).

[0098] The above-described frame sequences or exchanges 602, 606, and 608 may utilize, for example, one or more of: management frames (e.g., action frames), A control fields within data frames, and / or control frames. In some embodiments, any client associated with AP1 that accesses the primary link prior to AP1 accessing the primary link may relinquish a portion or all of its TXOP to AP1 in order to initiate the frame sequence 602 (e.g., by transmitting a frame that explicitly signals that the TXOP is being handed over to AP1).

[0099] As described above, according to the specified conditions of the TXOP handover, AP2 serves its clients on the primary link (e.g., frame sequence or exchange 606). Under condition 1, AP2 ensures that the primary link is not occupied for longer than the remainder of the TXOP duration signaled by AP1. Under condition 2, AP2 ensures that the primary link is occupied for exactly the remainder of the TXOP duration signaled by AP1.

[0100] Figure 7 According to some embodiments, according to the fourth CLS protocol, two BSSs ( Figure 2 ) and all on the same primary link. In some embodiments, AP1 wins medium access on the primary link and initiates a frame exchange 702 with AP2, during which AP1 and AP2 may exchange information about various parameters. The parameters may include, but are not limited to: 1. a parameter indicating whether the clients served by each AP in the following TXOP support link switching; 2. the CCA status of each AP on its respective non-primary link; and / or 3. a given TXOP duration for each AP's subsequent TXOP for either case: (a) if it remains on the primary link or (b) if it switches to the non-primary link, then determine a metric (e.g., such metric: throughput gain, latency reduction) that each AP achieves in the subsequent TXOP that its quality of service (QoS) is expected to improve by switching to the non-primary link compared to remaining on the primary link.

[0101] AP1 and AP2 use the information exchanged above to decide which AP can switch to the non-primary link in the subsequent TXOP and for the duration of the subsequent TXOP. In some embodiments, the decision is based on rules agreed upon in the frame exchange before the TXOP, or rules configured for the two APs by the network management entity. Examples of rules are one or more of the following rules:

[0102] i. Rule 1: If AP1 is intended to serve clients that support link switching operations, and AP2 is intended to serve clients that do not support link switching operations, then when AP1 switches to the non-primary link, AP2 shall remain on the primary link.

[0103] ii. Rule 2: If the CCA status of AP1 indicates that the non-primary link is idle / unoccupied, and the CCA status of AP2 indicates that the non-primary link is busy, then AP1 switches to the non-primary link, and AP2 remains on the primary link.

[0104] iii. Rule 3: If AP1 expects its QoS to be improved more than AP2 by switching to the non-primary link, then AP2 remains on the primary link while AP1 switches to the non-primary link.

[0105] iv. Rule 4: If AP1 remains on the primary link for exchange 706 and AP2 switches to the non-primary link for the subsequent TXOP for exchange 708, then the actual TXOP duration is selected based on the lesser of: (A) AP1's intended TXOP duration on the primary link, and (B) AP2's intended TXOP duration on the non-primary link plus any link switching or other delays associated with AP2 and its STAs switching to the non-primary link and back.

[0106] The frame exchanges 702, 704, and 708 may be performed using, for example, one or more of: management frames (e.g., action frames), A control fields within data frames, and / or control frames. After the frame exchanges, if AP1 is selected for link switching operations, then AP1 initiates a third CLS protocol (e.g., as in Figure 6 In some embodiments, AP1 may initiate a second CLS protocol to provide AP2 with an opportunity to switch to the non-primary link for the determined duration while AP1 serves its clients on the primary link, if AP2 is selected for the link switching operation, and AP1 may then initiate a second CLS protocol to provide AP2 with an opportunity to switch to the non-primary link for the determined duration while AP1 serves its clients on the primary link, or AP2 may directly initiate a first CLS protocol to switch to the non-primary link for the determined duration, after which AP1 serves its clients on the primary link. If neither AP1 nor AP2 is selected for the link switching operation, AP1 may utilize the remainder of its TXOP to serve its clients on the primary link. In some embodiments, any clients associated with AP1 may gain access to the primary link (e.g., by transmitting a frame that explicitly signals that the TXOP is switched to AP2) before AP1 may relinquish part or all of its TXOP to AP2 to initiate the fourth CLS protocol.

[0107] Figure 8 According to some embodiments, in accordance with the fifth CLS protocol AP1 (eg, Figure 2802.11be) and STA1315 (e.g., non-AP), STA2 325, and STA 322. AP1 has been operated by ILS on the non-primary link or switched there according to one of the first CLS protocol to the fourth CLS protocol for frame exchange 808. One or more clients or STAs have only listening capabilities on the non-primary link (e.g., the ability to only receive and decode non-HT frames without any Tx capabilities, which is also defined in 802.11be for EMLSR non-AP STAs). The AP transmits a trigger (MU-RTS or other frame) addressed to at least one client with only listening capabilities on the non-primary link. Upon receiving the trigger, the client with only listening capabilities switches to full Rx / Tx capabilities on the non-primary link. The AP may include a filler in the transmitted trigger to accommodate the link switching delay of the client. In some embodiments, STA3 or STA 322 may remain on the primary link and not switch to the non-primary link for exchange 808, depending on its capabilities.

[0108] In some embodiments, the non-primary link post-switching medium access protocol (as mentioned above) may be used in a scenario where a subset of the AP and associated clients have been switched to a non-primary link by ILS operation or according to one of the first to fifth CLS protocols. One or more rules may be implemented for medium access on the non-primary link, either by standards or by prior handshaking / negotiation between the AP and the client. The one or more rules include, but are not limited to:

[0109] 1. A client or STA may be restricted to transmit only when granted a transmission opportunity by the AP (e.g., in response to a frame from the AP). For example, a STA may not be allowed to initiate a TXOP itself. In some embodiments, this restriction may be indicated during the notification of the switch to the non-primary link (e.g., in exchange 802) or by prior negotiation (e.g., when the client associates to the AP, or by a subsequent change of operating mode as indicated by the AP or the client).

[0110] 2. If the AP does not know the condition of the medium on the non-primary link before switching to the non-primary link, the AP performs the following operations to initiate a TXOP on the non-primary link:

[0111] a. The AP first measures the air energy on the non-primary links and checks whether the energy is below a pre-defined threshold.

[0112] b. If this check is met, the AP transmits a single MU-RTS or other short frame that evokes a response, and waits for responses from one or more clients before further transmission / reception activity on the non-primary link.

[0113] c. The client can transmit to the AP on a non-primary link only if one of the following conditions is met:

[0114] i. The client is aware of prior medium conditions (eg, via detection of previous frames), and is therefore able to determine that the medium is currently idle (eg, using the same CCA mechanism as used on the primary link).

[0115] ii. The client is unaware of prior medium conditions, but has measured the current air energy, and performs a check to ensure that the measured energy is below a pre-defined threshold (which may be different from the threshold used by the AP).

[0116] Fig. 9 is an exemplary sequence diagram of CLS for a residential mesh network according to some embodiments. In some embodiments, a residential mesh network has a single root AP connected to an ISP / wide area network and one or more repeater APs connected to the root AP via a backhaul link, which is typically wireless. The root AP and repeater APs may be multi-band (e.g., supporting multiple radio links in parallel on different channels / bands) and may be co-located on the same set of channels for backhaul 902 and fronthaul 904 (e.g., on the primary link). The same channels may be time-shared between fronthaul 904 and backhaul 902 (e.g., under WiFi7 / 802.11be), and higher data rates may be utilized due to simultaneous transmit-receive (STR) multi-link operation (MLO) on the backhaul. In some embodiments, CLS operation achieves higher throughput / lower latency compared to default mesh operation, as shown below:

[0117] 1. The primary link of each radio on the root access point and repeater AP is on the same channel frequency.

[0118] 2. During backhaul operations (ie, when data is transmitted from the root AP to the repeater AP and vice versa), both the root AP and the repeater AP remain on the primary link of each radio.

[0119] 3. For fronthaul on each radio, the root AP and repeater AP coordinate (e.g., via one of the outlined CLS protocols) so that one of the APs continues to serve its clients on the primary link (e.g., fronthaul 904) while the other AP switches to the non-primary link along with its clients for fronthaul 906.

[0120] 4. In addition, since the root AP knows the active traffic flows to / from the STAs associated with itself and the repeater AP, the root AP can select the CLS protocol with the least overhead. For example, if there is active traffic for STAs that are capable of link switching operations and connected to the root AP, and for STAs that are not capable of link switching operations and connected to the repeater, the root AP can initiate the third CLS protocol when obtaining medium access to the primary link.

[0121] In some embodiments, the first CLS protocol ( Figure 4 ) or the fifth CLS agreement ( Figure 8 ) are used with dual-band APs to provide higher throughput. A dual-band AP has two fully capable radios. The first radio serves clients in the 2.4 GHz band, while the second radio serves clients in the 5 GHz to 6 GHz band. However, without a third full radio, these APs are often unable to take advantage of the wider channel bandwidth and lower congestion of the newly available 6 GHz to 7 GHz spectrum in certain locations. In some embodiments, the first CLS protocol or the fifth CLS protocol ( Figure 8 ) enables a dual-band AP to temporarily switch to a non-primary link in the 6 GHz to 7 GHz band to serve clients capable of 6 GHz operation via EMLSR link switching, thereby allowing higher throughput / lower latency than would be permitted by operating in the more congested 5 GHz to 6 GHz band. In some embodiments, a fronthaul operation or phase may refer to communication or data transfer between an AP and a client device associated with that AP. In some embodiments, a backhaul phase or operation may refer to communication or data transfer between a first AP and a second AP (e.g., data intended for or originating from a client device associated with one of the APs).

[0122] Embodiments of the devices and processes generally described above may be better understood by reference to the IEEE 802.11 Standard, which provides additional details regarding certain signals and operations disclosed herein and is not intended to limit the devices or processes described above in any way. (IEEE) Standards, which are hereby incorporated in their entirety into this disclosure (particularly, 802.11-2020; 802.11ax TM -2021IEEE standard 802.11ax TM -2021: High-efficiency WLAN (Revision 1), IEEE P802.11be TM / D2.2 and IEEE P802.11-REVme TM / Enhancement of D1.3. In some embodiments, a WiFi network may refer to a wireless network with Internet access.

[0123] Circuitry or circuitry may refer to any electronic circuit or combination of circuits. To the extent that a device, circuit, processor, or circuitry is described or recited in a claim as performing one or more operations or functions or being configured to perform one or more operations or functions, the performance of the recited functions or operations may be distributed across two or more devices, circuits, or processors without departing from the scope of the claims, unless those functions or operations are explicitly recited as being performed on a particular single circuit or group of circuits, processors, or devices (e.g., using the phrases "on a single circuit," "on a group of circuits comprising," or "on a single device").

[0124] It should be noted that certain paragraphs of the present disclosure may reference terms such as "first" and "second" related to transmission spatial streams, sounding frames, responses, and subsets of devices in order to identify or distinguish one another or between one another. In some embodiments, when the first device and the second device are access points, the second link of the first device may be different from the second link of the second device (for example, the second link may occupy different channel frequencies, may partially overlap in frequency, and may have different bandwidths). These terms are not intended to associate entities (for example, the first device and the second device) only in time or according to a sequence, although in some cases, these entities may include such a relationship. These terms also do not limit the number of possible entities (for example, STA, AP, beam transmitter and / or beam receiver) that can operate within a system or environment. It should be understood that the system described above may provide multiple components of any one or each of those components, and these components may be provided on a standalone machine, or in some embodiments, on multiple machines in a distributed system. In addition, the bit field position may change, and multi-bit words may be used. In addition, the systems and methods described above may be provided as one or more computer-readable programs or executable instructions embodied on or in one or more articles of manufacture, such as a floppy disk, hard disk, CD-ROM, flash memory card, PROM, RAM, ROM, or tape. The programs may be implemented in any programming language, such as LISP, PERL, C, C++, C#, or in any bytecode language, such as JAVA. The software programs or executable instructions may be stored as object code on or in one or more articles of manufacture.

[0125] Although the foregoing written description of the methods and systems enables one skilled in the art to make and use embodiments thereof, one skilled in the art will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiments, methods, and examples herein. Therefore, the methods and systems should not be limited to the embodiments, methods, and examples described above, but rather to all embodiments and methods within the scope and spirit of the present disclosure.

Claims

1. A first device, comprising: Circuitry configured to provide frames to a second device across a connection consisting of one or more links, the first device and the second device being access points, wherein the circuitry is configured to provide a transmission opportunity duration on the first link and an opportunity for the second device to switch to a second link.

2. The first device of claim 1, wherein the circuit is configured to perform one or more of the following operations:

1. if the second device serves clients that support link switching and the first device serves clients that do not support link switching, keeping the first device on the first link; 2. If the clear channel assessment status of the first device indicates that the second link is idle / unoccupied and the clear channel assessment status of the second device indicates that the second link is busy, switching the first device to the second link; Or 3. If the first device expects that the quality of service of the first device will be more improved by switching to the second link than that of the second device, then switching the first device to the second link.

3. The first device of claim 1 , wherein the circuit is configured to transmit a trigger on the second link after the first device has switched to the second link, the trigger being addressed to at least one client device having listen-only capability on the second link, and the trigger causing the at least one client device to switch to full receive and transmit capability on the second link.

4. A first device according to claim 1, wherein the circuit is configured to provide a frame to a third device across a connection, wherein the circuit is configured to detect a first frame from an overlapping basic service set on the first link and determine a second transmission opportunity duration of the overlapping basic service set, wherein the circuit is configured to switch the first device to the second link or the third link if the received signal strength of the first frame exceeds a first threshold and the second transmission opportunity duration exceeds a second threshold.

5. The first apparatus of claim 1, wherein the frame is provided according to an 802.11 protocol. 6 . The first device of claim 4 , wherein the circuit is configured to receive a second frame from the third device or transmit a third frame to the third device on the second link or a third link during the second transmission opportunity duration.

7. The first device of claim 4, wherein the circuit is configured to switch the first device back to the first link no later than when the second transmission opportunity duration expires.

8. The first device of claim 1, wherein the second device is configured to operate on the first link according to rules associated with the transmission opportunity duration.

9. The first device of claim 1, wherein the first device and the second device are configured to operate on the first link within a backhaul phase, and one of the first device or the second device is configured to operate on the second link during a fronthaul phase.

10. A first device, comprising: Circuitry configured to provide a frame to a second device across a connection comprised of one or more links, wherein the circuitry is configured to detect a first frame from an overlapping basic service set on a first link and determine a first duration of a transmission opportunity for the overlapping basic service set, wherein the circuitry is configured to perform one or more of the following operations:

1. Switch the first device to a second link, and the first device remains on the second link until the duration minus a time to complete a link switch operation from the second link to the first link expires; 2. If a new frame addressed to the first device or a clear-to-send frame addressed to the second device is received within a third duration, the first device is switched to the second link, and the first device remains on the second link until the second duration expires; 3. If the second link continues to be busy / unavailable for a fourth duration, switching the first device back to the first link after switching to the second link; 4. If the second device notifies the first device to switch back to the first link before the expiration of the first duration, switching the first device back to the first link after switching to the second link; Or 5. If the measured received signal strength RSSI of the first frame exceeds a first threshold and the first duration exceeds a second threshold, switching the first device to a second link. The first device of claim 10 , wherein the second device is an access point.

12. The first device of claim 10, wherein the first frame is detected as being from an overlapping service set using a setting in a physical layer preamble.

13. The first device of claim 12, wherein the first device is an access point, and the setting is a split number, a modulation coding scheme, or a bandwidth or a physical layer version setting that is not supported by the first device.

14. The first device of claim 10, wherein the first device is an access point and detects the first frame as being from an overlapping service set in response to data in an uplink / downlink field.

15. The first apparatus of claim 10, wherein the frame is provided according to an 802.11 protocol.

16. A first device, comprising: Circuitry configured to provide frames to a second device and a third device across a connection consisting of one or more links, the first device being an access point and the second device and the third device being client devices, wherein the circuitry is configured to initiate a sequence of frames upon obtaining access to a medium on a first link, the sequence of frames providing a transmission opportunity duration, wherein the circuitry is configured to switch the first device to a second link after the sequence of frames and to switch the first device back to the first link no later than when the transmission opportunity duration expires.

17. The first device of claim 16, wherein the sequence of frames notifies the second device to move to the second link, while the third device remains on the first link and does not attempt to communicate with the AP on the first link during the transmission opportunity duration.

18. The first device of claim 16, wherein the circuit is configured to transmit a trigger on the second link addressed to at least one client device with listen-only capability on the second link, wherein the trigger causes the at least one client device with listen-only capability to switch to full receive and transmit capability on the second link.

19. The first device of claim 16, wherein a fourth device is an access point, and the first device is configured to receive a notification from the fourth device for switching the first device to the second link, and the fourth device remains on the first link.

20. A first device according to claim 16, wherein the fourth device is an access point, and the first device is configured to provide a notification to the fourth device for causing the first device to switch to the second link, and the fourth device remains on the first link, and the notification allows the fourth device to utilize the first link for a duration that does not exceed or exactly matches the transmission opportunity duration.

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