Network-supported multi-connection operation for single radio devices

Abstract

A system comprises a first multi-link operation (MLO) device and a second MLO device. The first MLO device sends a frame to the second MLO device via a first link. The frame includes a link occupancy information field containing link occupancy information for a second link.

Description

[0001] The present disclosure relates to wireless devices and, more particularly, to network-assisted multi-link operation for single-radio devices.

[0002] Wireless local area network (WLAN) technology has evolved over generations. The latest generation of WLAN devices is based on a multi-link operation (MLO) system, in which devices can connect using multiple links / channels. Depending on the complexity of a device, new standards, such as Wi-Fi® 7 (802.11be), define different classes of devices. Simultaneous transmit / receive (STR) devices have more than one parallel connection and can independently and simultaneously perform transmit (Tx) and receive (Rx) operations over these connections.With the ability to monitor and perform channel access control on multiple links / channels simultaneously using P-CRS (Physical Carrier Sense) and V-CRS (Virtual Carrier Sense), these devices can send latency-critical traffic on any of the links based on link / channel access and availability. MLSR (Multiple Links, Single Radio) devices have multiple links but can only operate on one link at a time (Tx and Rx). Therefore, MLSR devices do not have real-time access to P-CRS and V-CRS for other links. This prevents MLSR devices from performing any real-time link / channel access and / or selection, limiting their performance in terms of achievable latency compared to other device classes.The inability of MLSR devices to perform any real-time link access and / or selection also impacts the design complexity with regard to link / channel probing. Enhanced MLSR or eMLSR devices have additional control link(s) that can monitor all links / channels simultaneously, providing access to P-CRS and V-CRS across all links / channels. However, this comes at the cost of larger silicon area and higher power consumption.

[0003] One task is to improve known approaches.

[0004] This object is achieved according to the features of the independent claims. Preferred embodiments can be found in particular in the dependent claims.

[0005] The examples proposed herein may, in particular, be based on at least one of the following solutions. In particular, combinations of the following features may be used to achieve a desired result. The features of the system may be combined with any feature(s) of the method, or vice versa.

[0006] For example, a system is proposed that includes: - a first multiple link operation (MLO) device; - a second MLO device, - wherein the first MLO device serves to: - Sending a frame to the second MLO device over a first connection, the frame comprising a link occupancy information field comprising link occupancy information of a second connection.

[0007] It is a further development that the frame comprises a legacy frame having a plurality of legacy fields, and wherein the connection usage information field is an additional field added to the plurality of legacy fields.

[0008] It is a further development that the frame is an MLO-compatible Request-To-Send or RTS frame and / or an MLO-compatible Clear-To-Send or CTS frame.

[0009] It is a further development that the connection occupancy information includes connection occupancy duration information.

[0010] It is a further development that the connection occupancy information includes network assignment vector (NAV) information and / or virtual carrier sensing (V-CRS) information

[0011] It is a further education that - the first MLO device is a simultaneous transmit and receive (STR) device and / or an enhanced multi-link single radio (eMLSR) device; - the second MLO device is a multi-link single radio (MLSR) device.

[0012] It is a further development that the second MLO device serves to - Receiving the frame via the first connection; - Extracting the connection usage information of the second connection; - Determining whether to switch to the second connection based on the connection usage information of the second connection.

[0013] It is a further development that the connection occupancy information of the second connection indicates that a status of the second connection is unknown.

[0014] A procedure is also specified, comprising the steps: - receiving a frame from an access point over a first connection, the frame comprising a link occupancy information field comprising link occupancy information of a second connection. - Extracting the connection usage information of the second connection; - Determine whether to switch to the second connection based on the connection usage information.

[0015] It is a further development that the frame comprises a legacy frame having a plurality of legacy fields, and the connection usage information field is an additional field added to the plurality of legacy fields.

[0016] It is a further development that the frame is an MLO-compatible Request-To-Send or RTS frame and / or an MLO-compatible Clear-To-Send or CTS frame.

[0017] It is a further development that the connection occupancy information includes connection occupancy duration information.

[0018] It is a further development that the connection occupancy information comprises network assignment vector (NAV) information and / or virtual carrier sensing (V-CRS) information.

[0019] It is a further development that the access point comprises a simultaneous transmit and receive (STR) device and / or an enhanced multi-link single radio (eMLSR) device.

[0020] A procedure is also specified, comprising the steps: - Determining connection occupancy information of a first connection; - transmitting a frame to a station device over a second connection, the frame comprising a link occupancy information field comprising link occupancy information of the first connection.

[0021] It is a further development that the frame comprises a legacy frame having a plurality of legacy fields, and the connection usage information field is an additional field added to the plurality of legacy fields.

[0022] It is a further development that the frame is an MLO-compatible Request-To-Send or RTS frame and / or an MLO-compatible Clear-To-Send or CTS frame.

[0023] It is a further development that the station device comprises a multi-link single radio (MLSR) device.

[0024] It is a further development that the connection occupancy information includes connection occupancy duration information.

[0025] It is a further development that the connection occupancy information comprises network assignment vector (NAV) information and / or virtual carrier sensing (V-CRS) information.

[0026] The described properties, features, and advantages, as well as the manner in which they are achieved, are further explained in connection with the following schematic description of exemplary embodiments, which are explained in more detail in conjunction with the drawings. For clarity, identical or equivalently functioning elements may be provided with the same reference numerals. Fig. 1 is a block diagram of an example wireless communication system according to some embodiments. Fig. 2 is a simplified timing diagram of network-assisted multi-connect operation for single-radio devices according to some embodiments. Fig. 3 is a simplified timing diagram of network-assisted multi-connect operation for single-radio devices according to some embodiments. Fig. 4 is an illustration of a simplified frame format for network-assisted multi-connect operation for single-radio devices according to some embodiments. Fig. 5 is a block diagram of frame generation and frame analysis for virtual carrier sensing in MLO according to some embodiments. Fig. 6A is a flowchart of a method for performing network-assisted multi-connection operation for single-radio devices, according to some embodiments. Fig. 6B is a flowchart of a method for performing network-assisted multi-connect operation for single-radio devices, according to some embodiments.

[0027] The following description sets forth numerous specific details, such as examples of specific systems, devices, components, methods, and so on, to ensure a thorough understanding of various embodiments of network-assisted multi-link operation for single-radio devices. Wireless local area network (WLAN) technology has evolved over generations of development. The latest generation of WLAN devices is based on a multi-link operation (MLO) system, in which devices can connect using multiple links / channels. Prior to Wi-Fi® 7, a link is a logical connection between a client device and an access point or router established on a specific channel frequency.In other words, a connection can only operate on the channel frequency on which the connection was established at a time, and the connection cannot be used for any other channel frequency (i.e., a single connection is assigned a channel frequency). The client device provides a SAP (Service Access Point) to the higher layer, which is mapped to the connection. However, Wi-Fi® 7 includes a proposed multi-connection operating technology in which multiple connections can be established, each using a different channel frequency, while higher-layer services are provided using one SAP. In other words, the SAP is mapped to multiple connections.

[0028] Depending on the complexity of a device, Wi-Fi® 7 standards define different classes of devices. Simultaneous transmit and receive (STR) devices have more than one parallel link and can independently and simultaneously perform transmit (Tx) and receive (Rx) operations over these links. With the ability to monitor and perform channel access control on multiple links / channels simultaneously using P-CRS (Physical Carrier Sense) and V-CRS (Virtual Carrier Sense), these devices can send latency-critical traffic on any of the links based on link / channel access and availability.

[0029] MLSR (multiple links, single radio) devices have multiple links but can only operate on one link at a time (Tx and Rx). Therefore, MLSR devices do not have real-time access to P-CRS and V-CRS for other links. This prevents MLSR devices from performing any real-time link / channel access and / or selection, limiting their performance in terms of achievable latency compared to other device classes. Such a design optimizes device cost but has significant limitations in terms of latency performance. The inability of MLSR devices to perform any real-time link access and / or selection also impacts the design complexity with regard to link / channel probing.

[0030] Enhanced MLSR or eMLSR devices have additional control link(s) that can monitor all links / channels simultaneously, providing access to P-CRS and V-CRS across all links / channels. However, this comes at the expense of larger silicon area and higher power consumption.

[0031] To address these and other shortcomings and improve the limitations of MLSR devices, the present disclosure sets forth network-assisted multi-link operation for single-radio devices. By sharing link occupancy information (e.g., network-assigned vector (NAV) information) of other links on a link (when the device is not currently operating on the other links), MLSR devices can obtain some information about occupancy information of other links / channels (e.g., V-CRS) and therefore improve the inherent limitation of MLSR devices by incorporating this information into link / channel handoff decision making.Furthermore, by sharing link occupancy information, including remaining transmission opportunity (TxOP) information on other links (if the sharing device is currently participating in a transaction across the other links), MLSR devices can obtain some information about occupancy information of other links / channels (e.g., V-CRS) and thus improve the inherent constraints of these devices by incorporating this information into link / channel handoff decision making. This, in turn, helps MLSR devices achieve improved latency and / or power savings by avoiding unnecessary link / channel handoffs, as well as improved design complexity with regard to link / channel probing.

[0032] Thus, in at least some embodiments, a system is disclosed that includes a first MLO device and a second MLO device. In some embodiments, the first MLO device is an STR device and / or an eMLSR device, and the second MLO device is an MLSR device. In some embodiments, the first MLO device transmits a frame to the second MLO device over a first connection. In some embodiments, the frame includes a link occupancy information field that includes link occupancy information of a second connection.In some embodiments, the second MLO device receives the frame over the first connection, extracts the link occupancy information of the second connection, and determines whether to switch to the second connection based on the link occupancy information of the second connection. In some embodiments, the link occupancy information of the second connection included in the frame indicates that a status of the second connection is unknown.

[0033] In some embodiments, the frame may be a legacy frame that includes multiple fields, some of which may be legacy fields. For example, in some embodiments, the link occupancy information field may be added to the existing legacy frame (i.e., in addition to the multiple legacy fields already existing in legacy frames). A legacy frame may refer to a type of frame format used in earlier versions of a wireless protocol or standard (e.g., the IEEE 802.11ax, 802.11b, 802.11a, 802.11n, 802.11ac, etc.). Fields included in legacy frames may also be referred to as legacy fields (a field used in frames of an earlier version of a wireless protocol or standard). A legacy field may refer to a type of field included in frames of earlier versions of a wireless protocol or standard (e.g., the IEEE 802.11a, 802.11n, 802.11ac, etc.).11ax, 802.11b, 802.11a, 802.11n, 802.11ac, etc.). Legacy frames have a frame format that includes fields for the Media Access Control (MAC) header, the frame body, and the Frame Check Sequence (FCS) field. In some embodiments, the Link Occupancy Information field may be added to the existing legacy frame (i.e., in addition to the multiple legacy fields already existing in legacy frames).

[0034] Alternatively, the frame sent by the first MLO device over the first link to the second MLO device may be an MLO-compatible Request-To-Send (RTS) frame and / or an MLO-compatible Clear-To-Send (CTS) frame, as proposed. In some embodiments, an MLO-compatible RTS frame or an MLO-compatible CTS frame may be a legacy RTS or CTS frame. RTS and CTS frames are two control frames used in the IEEE 802.11 WLAN standard for managing access to the wireless medium. Each contains a duration / ID field that specifies the length of time the sender will occupy the wireless medium. This helps prevent other devices from transmitting during that time. In some embodiments, an MLO-compatible RTS frame or an MLO-compatible CTS frame may contain link occupancy information from some or all of the links or channels in a network.Such an MLO-compatible RTS frame or an MLO-compatible CTS frame may be received by any device in the network that occupies the channel or medium on which the frames are transmitted. In some embodiments, the link occupancy information includes link occupancy duration information (e.g., NAV timer, TxOP, etc.). In some embodiments, the link occupancy information of that connection includes corresponding Network Allocation Vector (NAV) information and / or TxOP information. Additional embodiments and variations in implementations are described in detail with reference to FIG. Fig. 1-6 discussed.

[0035] Current multi-link operation for MLSR devices does not give MLSR devices access to a V-CRS (virtual carrier sense) of other links / channels. The only way MLSR devices can obtain such carrier sense information is via a P-CRS (physical carrier sense) by performing a channel handover operation and physically probing the channel (e.g., via a P-CRS). As mentioned, a channel handover operation has an associated handover time or latency, which can add to the overall latency of a transmission. In some examples, under current multi-link operation, it may be possible that an MLSR device needs to perform a Tx operation, but the link / channel on which the MLSR device is currently active is unavailable. In this scenario, the MLSR device will perform a channel handover operation to access the CRS for another link / channel.In some examples, an MLRS device may need to perform multiple channel handoff operations (thereby adding multiple channel handoff times or latency periods to one operation) before it can transmit the queued frame(s), thus increasing the latency of that frame(s).

[0036] The present disclosure includes a number of advantages, including enabling MLSR devices to perform some real-time link access and / or selection. Furthermore, the present disclosure enables MLSR devices to exhibit improved latency and / or power savings by avoiding unnecessary link / channel hopping. This approach also results in improved design complexity with regard to link / channel probing. Additional advantages will be apparent to those skilled in the art of modern wireless technologies and recent IEEE standards. It should be noted that the present disclosure is not limited to applications in Wi-Fi® technologies, but may be implemented with any standard that utilizes multi-link operation.

[0037] Fig. 1 is a block diagram of an exemplary wireless communication system 100 according to some embodiments. In these embodiments, the wireless communication system 100 includes base stations and / or access points 112-116 (which may be referred to interchangeably herein), wireless devices 118-132 (e.g., wireless stations (STAs) and other such wireless communication devices), and a network hardware component 134. The wireless devices 118-132 may be laptop computers 118 or tablets 126, personal digital assistants 120 and 130, PCs 124 and 132, and / or cellular phones 122 and 128. The details of one embodiment of such wireless devices when acting as transmitting devices are described in more detail below.

[0038] In embodiments, the base stations (BSs) or access points (APs) 112-116 are operatively coupled to the network hardware component 134 via local network connections 136, 138, and 140. The network hardware 134, which may be a router, a switch, a bridge, a modem, a system controller, etc., provides a wide area network connection 142 for the communication system 100. Each of the base stations or access points 112-116 has an associated antenna or antenna array for communicating with the wireless communication devices within an area reachable by a respective base station or access point. Typically, the wireless devices register with a particular base station or access point 112-116 to receive services from the communication system 100. For direct connections (i.e.In point-to-point communications, wireless communication devices communicate directly over a dedicated channel.

[0039] Any of the various wireless devices 118-132 and BSs or APs 112-116 may include a processor and a communications interface to support communications with any other of the wireless devices 118-132 and BSs or APs 112-116. In one example of operation, a processor and the communications interface implemented within one of the devices (e.g., any of the wireless devices 118-132 and BSs and APs 112-116) are configured to process at least one signal received from another of the devices (e.g., any other of the wireless devices 118-132 and BSs or APs 112-116) and / or generate at least one signal to be transmitted thereto.

[0040] It is noted that a general reference to a communication device, such as a wireless device (e.g., wireless devices) 118-132 and BSs or APs 112-116 in Fig. 1 or any other communication devices and / or wireless communication devices may alternatively be referred to generally herein using the term 'device' for brevity. The processor and communication interface of any of the various devices, wireless devices 118-132, and BSs or APs 112-116 may be configured to support communications with any other of the various devices, wireless devices 118-132, and BSs or APs 112-116. Such communications may be unidirectional or bidirectional between devices.

[0041] In one example of operation, the AP / BS device 116 (representative of any of the BS or AP 112-116) includes a communications interface and a processor configured to receive one or more signals from the devices 130 and 132. Considering one example, the device 116 is an STR device or an eMLSR device. The device 132 is an MLSR device that receives a transmit or Tx request from a host (e.g., the device 132). The device 116 transmits a frame (e.g., control frame, RTS frame, data frame, and / or the like) containing link occupancy information of a second link over the first link.The device 132 receives the frame containing the link occupancy information of the first and second links and determines whether the first link or the second link should be used for transmission based on the P-CSR and V-CRS of the first link and the link occupancy information of the second link contained in the frame.

[0042] Fig. 2 is a simplified timing diagram 200 of network-assisted multi-connect operation for single-radio devices according to some embodiments.

[0043] Fig. Figure 2 illustrates the interaction of an STR-AP 230 with other station (STA) devices (e.g., STA 1 250, STA 2 270, and / or STA-MLSR 290) using network-assisted multi-connect operation for single-radio devices, according to some embodiments. In some embodiments, an AP device may be an STR device. For example, in some embodiments, the STR-AP 230 may be an STR device operating concurrently on two channels (Channel A 214 and Channel B 216). The STA 1 250 interacts with STR-AP 230 on channel A 214. The STR-AP 230 transmits an RTS frame 202A embedded with link occupancy information from channel A 214. Although a frame (e.g., the RTS frame 202A) is intended for a specific station (e.g., STA 1 250), all devices in the network can receive the frame over a first channel and extract link occupancy information of all other channels.Although the data in a data frame cannot be decrypted by a device other than the destination device, all devices can receive and decode the NAV information.

[0044] In some embodiments, link occupancy information includes a duration (i.e., how long the channel or link will be occupied). In some embodiments, link occupancy information, including duration information, is calculated by summing the elapsed time during each of the frames (e.g., control frames, RTS frames, CTS frames, data frames, B-ACK frames, and / or the like) to be sent during a transmission and includes SIFS (short inter-frame spaces) (e.g., SIFS 295) in the calculation.

[0045] The STA 1 250 sends a CTS frame 204A over channel A 214 and transmission begins on channel A 214. The STR-AP 230 sends data frames 210A-N on channel A 214 to STA 1 250. Once all data frames have been sent on channel A 214, the STA 1 250 sends a block acknowledgment (B-ACK) frame 206A to the STR-AP 230 on channel A 214, signaling the end of the transmission and the end of the NAV timer 312A.

[0046] The STA-MLSR 290, operating on channel A 214, receives the RTS frame 202A during transmission and extracts the embedded link occupancy information (e.g., NAV 212A) from channel A 214. In some embodiments, an NAV may be a timer indicating the time remaining for an ongoing transmission on a channel. In some embodiments, NAV information and / or NAV timers are maintained by an AP device (e.g., the STR-AP 230) for each link / channel in the network and each device in the network associated with the AP. The STA 2 270 interacts with STR-AP 230 on channel B 216. The STA 2 270 transmits a CTS frame 204B over channel B 216 after receiving an RTS frame 202B from the STR-AP 230. The STR-AP 230 begins transmitting on channel B 216 and transmits the data frames 210Q-W STA 2 270.Once all data frames have been sent on channel B 216, the STA 2 270 sends a B-ACK frame 206B to the STR-AP 230 on channel B 216, signaling the end of the transmission and the end of the NAV timer 312B.

[0047] The STR-AP 230 transmits a data frame 210B embedded with link occupancy information from channel B 216. The STA-MLSR 290, operating on channel A 214, receives the data frame 210B during transmission and extracts the embedded link occupancy information (e.g., NAV 212B) from channel B 216.

[0048] The STA-MLSR 290, operating on channel A 214, receives a Tx request 218 from a host. Using the extracted link occupancy information from channel A 214 and channel B 216, the STA-MLSR 290 determines which channel to use to satisfy the Tx request 218. When an MLSR device hops channels, there is an associated channel hop time (e.g., channel hop time 280). In the absence of other link / channel occupancy information, an MLSR device must hop channels when the current link / channel is busy to know the link / channel occupancy of other links / channels. The channel hop time 280 is added to the transmit latency of an MLSR device due to the increased latency associated with hops. For example, upon receiving the Tx request 218, the STA-MLSR 290 could switch to channel B 216 without knowing the status of channel B.Such a switch could result in the STA-MLSR 290 finding, via a P-CRS 260, that channel B is busy and will be busy longer than the STA-MLSR 290 needs to switch back to channel A 314. After performing another channel switch 280 back to channel A 214, the total latency increases (e.g., from latency 240A to latency 240B).

[0049] However, the link occupancy information from channel B 216 sent in data frame 210B to STA-MLSR 290 allows STA-MLSR 290 to (effectively) have a V-CRS and thus avoid multiple channel handoffs. Based on embedded link occupancy information from channel A 214 and channel B 216 (e.g., NAV 212A-B), STA-MLSR 290 determines to remain on channel A 214 for transmission because the link occupancy information from channel B (e.g., NAV 212B) indicates that channel A 214 will become available before channel B 216. In this example, MLSR-STA 290 determines not to handoff channels (e.g., from channel A 214 to channel B 216), resulting in improved latency (e.g., latency 240A) for data frame 210Z.

[0050] Once STA 1 250 has finished transmitting on channel A 214, STA-MLSR 290 enters channel contention on channel A 214 (see Contention 220) and then begins transmitting on channel A 214 starting with data frame 210Z.

[0051] In some embodiments, the MLSR station 290 may have access to channel occupancy information (e.g., NAVs 212B) of a second link (e.g., channel B 260). The link occupancy information may be embedded in a frame of another device (e.g., data frame 210B) and sent to the MLSR STA 290 over a first link (e.g., channel A 214). Such link occupancy information assists the MLSR STA 290 in determining whether a channel handoff operation may improve the latency of the packet (e.g., data frame 210Z).

[0052] A field shall be included in a frame per connection / channel to indicate the duration, as detected by the transmitting device, for which the corresponding connection / channel will be occupied. In some embodiments, a value (e.g., 0xFFFF) may be reserved to indicate that the link / channel status is unknown (since the device transmitting this frame may not have access to other link / channel occupancy). In some embodiments, a value of 0x0000 may indicate that a link / channel is available for channel access. In some embodiments, a SIFS (e.g., SIFS 295) is a period of time that elapses between transmissions of frames, as defined in the Wi-Fi® standards. In some embodiments, SIFS may be some type of inter-frame space (i.e., a period of time that must elapse between transmissions of two different frames on the network).

[0053] Fig. 3 is a simplified timing diagram 300 of network-assisted multi-connect operation for single-radio devices according to some embodiments.

[0054] In some embodiments, the link occupancy information may be included as part of an RTS or CTS frame that is modified to accommodate an MLO information exchange (e.g., MLO-compatible RTS or CTS). Such MLO-compatible RTS or CTS frames allow an MLSR device to have access to link / channel occupancy information based on RTS or CTS frames received from other devices in the network. Such access to link / channel occupancy information allows the MLSR device to determine whether a channel change is likely to improve or worsen (i.e., shorten or increase) the latency of the packet to be transmitted. In some examples, an MLSR device determines not to change channels, resulting in improved latency for that frame.

[0055] Fig. 3 illustrates the interaction of an STR-AP 330 with other station (STA) devices (e.g., STA 1 350, STA 2 370, and / or STA-MLSR 390) using network-assisted multi-connect operation for single-radio devices, according to some embodiments. For example, in some embodiments, the STR-AP 330 may be an STR device operating simultaneously on two channels (channel A 314 and channel B 316). The STA 1 350 interacts with STR-AP 330 on channel A 314. The STA 2 370 interacts with STR-AP 330 on channel B 316. The STR-AP 330 transmits an MLO-compatible RTS frame (MLO-RTS) 302A. The STA 2 370 sends an MLO-compatible CTS frame 304A to the STR-AP 330, and transmission of data frames 310A-M begins on channel B 316. Once all data frames have been sent by the STR-AP 330 on channel B, the STA 2 370 sends a B-ACK 306B to signal the end of the transmission, and the NAV timer 312B expires.

[0056] In some embodiments, link occupancy information includes a duration (i.e., how long the channel or link will be occupied). In some embodiments, link occupancy information, including duration information, is calculated by summing the elapsed time during each of the frames (e.g., control frames, RTS frames, CTS frames, data frames, B-ACK frames, and / or the like) to be sent during a transmission and includes SIFS (short inter-frame spaces) (e.g., SIFS 395) in the calculation.

[0057] The STA 1 350 interacts with STR-AP 330 on channel A 314. The STR-AP 330 sends an MLO-compatible RTS frame 302B embedded with link occupancy information of both channel A 314 and channel B 316. The STA 1 350 sends an MLO-compatible CTS frame 304B to the STR-AP 330, and transmission of data frames 310Q-W begins on channel A 314. Once all data frames have been sent by the STR-AP 330 on channel A 314, the STA 1 350 sends a B-ACK 306A to signal the end of the transmission, and the NAV timer 312A expires.

[0058] Although a frame (e.g., MLO-RTS frame 302B) is intended for a particular station (e.g., STA 1 350), all devices in the network may receive the frame over a first channel (e.g., channel A 314) and extract any embedded link occupancy information from other channels. In some embodiments, because the STA-MLSR operates on channel A 314, the STA-MLSR 390 may perform a P-CRS (e.g., P-CRS 360A) on channel A 314 to verify link occupancy information. In some embodiments, an NAV or NAV timer may be a timer that indicates the time remaining for an ongoing transmission on a channel.

[0059] The STA-MLSR 390, operating on channel A 314, receives a Tx request 318 from a host. Using the extracted link occupancy information of channel A 314 and channel B 316 from the MLO-compatible RTS frame 302B, the STA-MLSR 390 determines which channel to use to fulfill the Tx request 318.

[0060] When an MLSR device changes channels, there is an associated channel change time (e.g., channel change time 380). In the absence of other link / channel occupancy information, an MLSR device must change channels if the current link / channel is busy in order to know the link / channel occupancy of other links / channels. The channel change time 380 also adds to the transmit latency of MLSR devices due to the increased latency associated with changing channels. For example, if the STA-MLSR 390 were to change to channel B 316 upon receiving the Tx request 318 without knowing the status of channel B, it would find via P-CAS 360B that channel B 316 is busy for longer than it would take to change back to channel A 314. After performing another channel change 380 back to channel A 314, the total latency increases (e.g., from latency 340A to latency 340B).

[0061] However, the link occupancy information from channel A 314 and channel B 316 transmitted in the MLO-compatible RTS frame 302B to the STA-MLSR 390 allows the STA-MLSR 390 to (effectively) have a V-CRS and thus avoid multiple channel handoffs. The STA-MLSR 390 determines, based on embedded link occupancy information from channel A 314 and channel B 316 (e.g., NAV 312A-B), to remain on channel A 314 for transmission because the link occupancy information from channel B (e.g., NAV 312B) indicates that channel A 314 will become available before channel B 316. In this example, the MLSR STA 390 determines not to change channels (e.g., from channel A 314 to channel B 316), resulting in improved latency (e.g., latency 340A) for the data frame 310Z.

[0062] Once STA 1 350 has finished transmitting on channel A 314, STA-MLSR 390 enters access contention on channel A 314 (see contention 320) and then begins transmitting on channel A 314 starting with data frame 310Z.

[0063] In some embodiments, the MLSR station 390 may have access to channel occupancy information (e.g., NAVs 312B) of a second link (e.g., channel B 316). The link occupancy information may be embedded in a frame of another device (e.g., the MLO RTS frame 302B) and sent to the MLSR STA 390 over a first link (e.g., channel A 314). Such link occupancy information assists the MLSR STA 390 in determining whether a channel handoff operation may improve the latency of the packet (e.g., data frame 310Z).

[0064] In some embodiments, a field is included in an MLO-compliant frame per connection / channel to indicate the duration, previously acquired by a transmitting device, for which the corresponding connection / channel will be occupied. In some embodiments, a value (e.g., 0xFFFF) may be reserved to indicate that the link / channel status is unknown (since the device transmitting this frame may not have access to other link / channel occupancy). In some embodiments, a value of 0x0000 may indicate that a link / channel is available for channel access. In some embodiments, a SIFS (e.g., SIFS 395) is a period of time that elapses between transmissions of frames, as defined in the Wi-Fi® standards. In some embodiments, SIFS may be some type of inter-frame space (i.e.,, a period of time that must elapse between the transmissions of two different frames on the network).

[0065] Fig. 4 is an illustration 400 of a frame format for network-assisted multi-connect operation for single-radio devices, according to some embodiments. In WLAN communication, frames are used to exchange data between devices. There may be several types of frames, including RTS frames, CTS frames, ACK frames, block acknowledgement frames, data frames, etc.

[0066] In some embodiments, frame control field 402 is followed by duration / ID fields 1 through N. In some embodiments, the duration field specifies the amount of time the transmitter intends to occupy the channel. This duration includes the time required to send the data packet plus any additional time required for CTS / ACK frames. In some embodiments, the duration field specifies the amount of time the receiver will occupy the channel. In some embodiments, the duration fields may include NAVs and / or NAV timers. This duration includes the time required for the receiver to receive the data packet and return an ACK frame to the transmitter. In some embodiments, the duration / ID frames may be provided for all links / channels in a network.

[0067] In some embodiments, address fields 1 through 4 follow duration / ID fields 1 through N. In some embodiments, a sequence control field 417 may be inserted between at least two of address fields 1 through 4 (e.g., sequence control field 417 follows address fields 1 through 3 and comes before address field 4 418). In some embodiments, a frame body 420 follows address field 418. In some embodiments, an FCS field 422 follows frame body 420. In some embodiments, the duration / ID fields contain the duration information of multiple connections (e.g., link occupancy information) in the MAC headers of control frames and / or data frames. In some embodiments, the duration / ID fields contain the duration information for connections (e.g., link occupancy information) in special MLO-RTS / MLO-CTS frames (e.g., the MLO-compatible RTS frame 302B of Fig. 3). The link occupancy information contained in the duration / ID fields of a frame sent over a particular link may correspond to that link and / or any other links / channels in the network.

[0068] Fig. 5 is a block diagram 500 of frame generation and frame analysis for virtual carrier sensing in MLO according to some embodiments.

[0069] In some embodiments, frame generation and frame parsing for virtual carrier sensing during MLO transmissions are performed by STR and eMLSR devices. In some embodiments, a frame generator inserts the duration of a packet into a Duration_N field in the MAC header of frames corresponding to Connection_N when the transmission occurs on Connection_N, and inserts the NAV timer from the other Connection_M into other Duration_M.

[0070] In some embodiments, frame generation and frame parsing for virtual carrier sensing upon MLO reception are performed by STR and eMLSR devices. In some embodiments, a frame parser parses a duration_N and duration_M (e.g., durations D1 and D2) from received frames of two connections (e.g., connection 1 501 and connection 2 502) and updates the NAV timers of the corresponding connections.

[0071] In some embodiments, frame generation and frame parsing for virtual carrier sensing during MLO transmissions are performed by MLSR devices (e.g., MLO device 2 560). In some embodiments, a frame generator (e.g., frame generator 510C) inserts the duration of the packet (e.g., link occupancy information) into the Duration_N field (e.g., D1) in the MAC header of the frame corresponding to Link_N (e.g., Link 1 501) when the transmission occurs on that Link_N, and inserts a predefined identifier (e.g., 0xFFFF) to indicate that the state of the other link is unknown to MLSR device 2 560.

[0072] In some embodiments, frame generation and frame parsing for virtual carrier sensing during MLO reception are performed by MLSR devices. In some embodiments, a frame parser parses a duration_N and duration_M (e.g., durations D1 and D2) from received frames from two connections (e.g., connection 1 501 and connection 2 502), for example, while the MLSR device has switched to connection 2 502 and obtained duration_M or D2 from the received frame on connection 2 502, and updates the NAV timers of the corresponding connections.

[0073] In some embodiments, the received frames may be transmitted by an STR and / or an eMLSR device (e.g., the MLO device 1 550). In other embodiments, the received frames may be transmitted by an MLSR device.

[0074] In some embodiments, link occupancy information (e.g., NAV information, NAV timers, etc.) corresponding to links may be used to determine which link / channel a device can use to perform a transmission. In some embodiments, an MLSR device may also maintain multiple NAV timers to track the status of multiple links and / or channels.

[0075] In some embodiments, link occupancy information may be shared in either a legacy control frame or an MLO-compliant RTS or CTS control frame. Legacy RTS and CTS control frames already contain a field for link occupancy information. In some embodiments, an MLO-compliant RTS or CTS frame may include additional link occupancy information corresponding to links / channels other than the link / channel on which the MLO-compliant RTS or CTS frame is sent. In some embodiments, a legacy frame refers to frame types that are already part of current or future WLAN standards.

[0076] Fig. 6A-B are flowcharts of methods for performing network-assisted multi-connect operation for single-radio devices, according to some embodiments. Methods 600A-B may be executed by processing logic that may include hardware (e.g., a processing device, circuitry, dedicated logic, programmable logic, microcode, device hardware, integrated circuit, etc.), software (e.g., instructions running or being executed on a processing device), or a combination thereof. In some embodiments, methods 600A-B are performed by control logic and / or hardware of one of the MLO devices of Fig. 1 or Fig. 5. Although shown in a particular sequence or order, the order of the processes may be modified unless otherwise noted. Accordingly, the illustrated embodiments should be considered examples only, and the illustrated processes may be performed in a different order, and some processes may be performed in parallel. Furthermore, one or more processes may be omitted from various embodiments. Accordingly, not all processes are required in every embodiment. Other process flows are possible.

[0077] Fig. 6A is a flowchart of a method for performing network-assisted multi-connection operation for single-radio devices, according to some embodiments.

[0078] The method 600A begins in block 602, where processing logic executing the method receives a frame from an access point over a first connection, the frame including a link occupancy information field including link occupancy information of a second connection.

[0079] In some embodiments, the frame may be a legacy frame with multiple legacy fields, and the link occupancy information field may be an additional field added to the legacy fields of the legacy frame. For example, in some embodiments, the link occupancy information field may be added to the existing legacy frame (i.e., in addition to the multiple legacy fields already existing in legacy frames). A legacy frame, in some embodiments, may refer to a type of frame format used in earlier versions of a wireless protocol or standard (e.g., the Wi-Fi 6, IEEE 802.11ax wireless standards). Fields included in legacy frames may also be referred to as legacy fields (a field used in frames of an earlier version of a wireless protocol or standard).A legacy field, in some embodiments, may refer to a type of field used in previous versions of a wireless protocol or standard (e.g., the IEEE 802.11ax wireless standard). Legacy frames have a frame format that includes fields for the MAC header, the frame body, and the FCS field. In some embodiments, the link occupancy information field may be added to the existing legacy frame (i.e., in addition to the multiple legacy fields already existing in legacy frames).

[0080] In some embodiments, the frame may be an MLO-compatible RTS frame and / or an MLO-compatible CTS frame. In some embodiments, an MLO-compatible RTS frame or an MLO-compatible CTS frame may be a legacy RTS or CTS frame. RTS and CTS frames are two control frames used in the IEEE 802.11 WLAN standard for managing access to the wireless medium. Each contains a duration / ID field that specifies the length of time the sender will occupy the wireless medium. This helps prevent other devices from transmitting during that time. In some embodiments, an MLO-compatible RTS frame or an MLO-compatible CTS frame may contain link occupancy information from some or all of the links or channels in a network.Such an MLO-compatible RTS frame or an MLO-compatible CTS frame can be received by any device in the network that occupies the channel or medium on which the frames are transmitted.

[0081] In some embodiments, the link occupancy information includes link occupancy duration information. Duration information may include the amount of time a transmission will take or the time remaining in a transmission. In some embodiments, this may be expressed as an NAV or NAV timer.

[0082] In some embodiments, the link occupancy information includes NAV information and / or V-CRS information.

[0083] In some embodiments, the access point may be an STR device and / or an eMLSR device. In some embodiments, the second MLO device is a multi-link single-radio or MLSR device.

[0084] In block 604, the processing logic extracts (e.g., decodes) the connection usage information of the second connection.

[0085] In block 604, the processing logic determines whether to switch to the second connection based on the connection usage information.

[0086] Fig. 6B is a flowchart of a method for performing network-assisted multi-connect operation for single-radio devices, according to some embodiments.

[0087] Method 600B begins in block 612, where processing logic executing the method determines link occupancy information of a first link. In some embodiments, the link occupancy information is determined via P-CRS or V-CRS. In some embodiments, an STR or eMLSR device determines the link occupancy information. In some embodiments, an MLSR device determines the link occupancy information.

[0088] In block 614, the processing logic sends a frame to a station device (e.g., the STA-MLSR 290 of Fig. 2) via a second connection, wherein the frame comprises a connection occupancy information field comprising the connection occupancy information of the first connection.

[0089] In some embodiments, the frame may be a legacy frame with multiple legacy fields, and the link occupancy information field may be an additional field added to the legacy fields of the legacy frame. For example, in some embodiments, the link occupancy information field may be added to the existing legacy frame (i.e., in addition to the multiple legacy fields already existing in legacy frames). In some embodiments, a legacy frame may refer to a type of frame format used in earlier versions of a wireless protocol or standard (e.g., the IEEE 802.11ax wireless standard). Fields included in legacy frames may also be referred to as legacy fields (a field used in frames of an earlier version of a wireless protocol or standard).A legacy field, in some embodiments, may refer to a type of field used in earlier versions of a wireless protocol or standard (e.g., the IEEE 802.11ax wireless standard). Legacy frames have a frame format that includes fields for the MAC header, the frame body, and the FCS field. In some embodiments, the link usage information field may be an additional field added to multiple fields (i.e., legacy fields) that already exist in legacy frames. In some embodiments, the link usage information field may be added to the existing legacy frame (i.e., in addition to the multiple legacy fields already existing in legacy frames).

[0090] In some embodiments, the frame may be an MLO-compatible RTS frame and / or an MLO-compatible CTS frame. In some embodiments, an MLO-compatible RTS frame or an MLO-compatible CTS frame may be a legacy RTS or CTS frame. RTS and CTS frames are two control frames used in the IEEE 802.11 WLAN standard for managing access to the wireless medium. Each contains a duration / ID field that specifies the length of time the sender will occupy the wireless medium. This helps prevent other devices from transmitting during that time. In some embodiments, an MLO-compatible RTS frame or an MLO-compatible CTS frame may contain link occupancy information from some or all of the links or channels in a network.Such an MLO-compatible RTS frame or an MLO-compatible CTS frame can be received by any device in the network that occupies the channel or medium on which the frames are transmitted.

[0091] In some embodiments, the station device may be a multi-link single radio (MLSR) device.

[0092] In some embodiments, the link occupancy information may include link occupancy duration information. Duration information may include the amount of time a transmission will take or the time remaining in a transmission. In some embodiments, this may be expressed as an NAV or NAV timer.

[0093] In some embodiments, the link occupancy information may include NAV information and / or V-CRS information.

[0094] Those skilled in the art will understand that at least some embodiments may be practiced without these specific details. In other instances, well-known components, elements, or methods are not described in detail or are presented in simple block diagram format in order not to unnecessarily obscure the subject matter described herein. Accordingly, the specific details set forth below are merely exemplary. Particular implementations may depart from these exemplary details and still be considered within the spirit and scope of the present embodiments.

[0095] Reference in the specification to "one embodiment," "one embodiment," "one embodiment," "some embodiments," and "various embodiments" means that a particular feature, structure, step, operation, or characteristic described in connection with the embodiment(s) is included in at least one embodiment. Furthermore, the use of the phrases "one embodiment," "one embodiment," "one embodiment," "some embodiments," and "various embodiments" in various places in the specification do not necessarily all refer to the same embodiment(s).

[0096] The description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show illustrations according to embodiments. These embodiments, which may be referred to herein as "examples," are described in sufficient detail to enable those skilled in the art to practice the embodiments of the claimed subject matter described herein. The embodiments may be combined, other embodiments may be utilized, or structural, logical, and electrical changes may be made without departing from the scope and spirit of the claimed subject matter. It is to be understood that the embodiments described herein are not intended to limit the scope of the subject matter, but rather to enable those skilled in the art to make, make, and / or use the subject matter.

[0097] Certain embodiments may be implemented by firmware instructions stored on a non-transitory computer-readable medium, such as volatile memory and / or non-volatile storage. These instructions may be used to program and / or configure one or more devices including processors (e.g., CPUs) or equivalent devices (e.g., processing cores, processing engines, microcontrollers, and the like) such that the instructions, when executed by the processor(s) or their equivalents, cause the device(s) to perform the described operations for the USB-C / PD mode transition architecture described herein. The non-transitory computer-readable storage medium may include, but is not limited to, an electromagnetic storage medium, read-only memory (ROM), random access memory (RAM), erasable programmable memory (e.g.,EPROM and EEPROM), flash memory, or any other currently known or later developed non-transitory type of medium suitable for storing information.

[0098] Although the operations of the present circuit(s) and block(s) are shown and described in a particular order, in some embodiments, the order of operations of each circuit / block may be changed so that certain operations are performed in a reverse order, or so that certain operations may be performed at least partially concurrently and / or in parallel with other operations. In other embodiments, instructions or sub-operations of individual operations may be performed intermittently and / or alternately.

Claims

[1] System comprising: - a first multiple link operation (MLO) device; - a second MLO device, wherein the first MLO device serves to: - Sending a frame to the second MLO device over a first connection, the frame comprising a link occupancy information field comprising link occupancy information of a second connection. [2] The system of claim 1, wherein the frame comprises a legacy frame having a plurality of legacy fields, and wherein the link occupancy information field is an additional field added to the plurality of legacy fields. [3] System according to one of the preceding claims, wherein the frame is an MLO-compatible Request-To-Send (RTS) frame and / or an MLO-compatible Clear-To-Send (CTS) frame. [4] A system according to any preceding claim, wherein the call occupancy information comprises call occupancy duration information. [5] System according to one of the preceding claims, wherein the connection occupancy information comprises network assignment vector (NAV) information and / or virtual carrier sensing (V-CRS) information [6] System according to one of the preceding claims, in which - the first MLO device is a simultaneous transmit and receive (STR) device and / or an enhanced multi-link single radio (eMLSR) device; - the second MLO device is a multi-link single radio (MLSR) device. [7] A system according to any preceding claim, wherein the second MLO device is for - Receiving the frame via the first connection; - Extracting the connection usage information of the second connection; - Determining whether to switch to the second connection based on the connection usage information of the second connection. [8] A system according to any preceding claim, wherein the connection occupancy information of the second connection indicates that a status of the second connection is unknown. [9] Method comprising: - receiving a frame from an access point over a first connection, the frame comprising a link occupancy information field comprising link occupancy information of a second connection. - Extracting the connection usage information of the second connection; - Determine whether to switch to the second connection based on the connection usage information. [10] The method of claim 9, wherein the frame comprises a legacy frame having a plurality of legacy fields, and the link occupancy information field is an additional field added to the plurality of legacy fields. [11] Method according to one of claims 9 or 10, wherein the frame is an MLO-compatible Request-To-Send (RTS) frame and / or an MLO-compatible Clear-To-Send (CTS) frame. [12] Method according to one of claims 9 to 11, wherein the connection occupancy information comprises connection occupancy duration information. [13] Method according to one of claims 9 to 12, wherein the connection occupancy information comprises network assignment vector (NAV) information and / or virtual carrier sensing (V-CRS) information. [14] A method according to any one of claims 9 to 13, wherein the access point comprises a simultaneous transmit and receive (STR) device and / or an enhanced multi-link single radio (eMLSR) device. [15] Method comprising: - Determining connection occupancy information of a first connection; - transmitting a frame to a station device over a second connection, the frame comprising a link occupancy information field comprising link occupancy information of the first connection. [16] The method of claim 15, wherein the frame comprises a legacy frame having a plurality of legacy fields, and the link occupancy information field is an additional field added to the plurality of legacy fields. [17] Method according to one of claims 15 or 16, wherein the frame is an MLO-compatible Request-To-Send (RTS) frame and / or an MLO-compatible Clear-To-Send (CTS) frame. [18] A method according to any one of claims 15 to 17, wherein the station device comprises a multi-link single radio (MLSR) device. [19] Method according to one of claims 15 to 18, wherein the connection occupancy information comprises connection occupancy duration information. [20] A method according to any one of claims 15 to 19, wherein the connection occupancy information comprises network assignment vector (NAV) information and / or virtual carrier sensing (V-CRS) information.

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