Probing of beamformer requests

Abstract

The invention relates to sounding of beamformer requests. Exemplary implementations relate to methods and systems for operating a wireless transceiver employing a probing protocol that includes a request for an active communication sequence, the method and system comprising, for each of received dedicated training signals, in response to a probing trigger, transmitting a request for the active communication sequence to the wireless transceiver, a sounding trigger is transmitted to one or more beamforming receivers via a forward channel, and at least one dedicated training signal is received from the one or more beamforming receivers via a backward channel. The method further includes estimating a forward CSI derived based on a dedicated training signal from an associated beamforming receiver; and wherein a subsequent packet is pre-coded with a pre-code derived from the forward CSI for transmission via the forward channel to the associated beamforming receiving end. Exemplary aspects include scheduling a plurality of dedicated training signals from one or more beamforming receivers based on a single sounding trigger.

Description

[0001] Information about divisional applications

[0002] This application is a divisional application of the invention patent application with the invention name “Detection of Beamformer Requests”, application number 201980030224.8 and application date May 3, 2019.

[0003] CROSS-REFERENCE TO RELATED APPLICATIONS

[0004] This application claims the benefit of prior-filed co-pending provisional application No. 62 / 667,405, filed on May 4, 2018, with the U.S. Patent and Trademark Office, entitled “BEAMFORMER SOLICITED SOUNDING,” and co-pending non-provisional application No. 16 / 403,073, filed on May 3, 2019, with the U.S. Patent and Trademark Office, entitled “BEAMFORMER SOLICITED SOUNDING.” Technical Field

[0005] Aspects of the present disclosure relate generally to sounding for wireless communication operations, and particularly to systems and methods for beamformer requested sounding and operations thereof. Background Art

[0006] Home, outdoor, and office networks, also known as wireless local area networks (WLANs), are established using devices called wireless access points (WAPs). WAPs may include routers. WAPs wirelessly couple all the devices of a home network (e.g., wireless stations such as computers, printers, televisions, digital video (DVD) players, security cameras, and smoke detectors) to each other and to the cables or subscriber lines that deliver the Internet, video, and television to the home. Most WAPs implement the IEEE 802.11 standard, which is a contention-based standard for handling communications between multiple competing devices sharing a wireless communication medium on a selected one of multiple communication channels. The frequency range of each communication channel is specified in a corresponding one of the IEEE 802.11 protocols being implemented (e.g., "a," "b," "g," "n," "ac," "ad"). Communications follow a hub and spoke model, with a WAP at the hub and spokes corresponding to wireless links to each "client" device.

[0007] After selecting a single communication channel for the associated home network, access to the shared communication channel relies on a multiple access method identified as Collision Sense Multiple Access (CSMA). CSMA is a distributed random access method for sharing a single communication medium that is achieved by having competing communication devices back off and retry access if a collision on the wireless medium is detected (e.g., if the wireless medium is in use).

[0008] Communications over a single communications medium are identified as "simplex", meaning one communication stream from a single source node to one or more destination nodes at a time, with all remaining nodes able to "listen" to the subject transmission. Starting with the IEEE 802.11ac standard, and specifically with its 'Wave 2', discrete communications with more than one destination node can occur simultaneously using the so-called Multi-User (MU) Multiple-Input Multiple-Output (MIMO) capability of the WAP. The MU capability was added to the standard to enable the WAP to communicate simultaneously with single-antenna single-stream or multi-antenna multi-stream transceivers, thereby increasing the available time for discrete MIMO video links to wireless HDTVs, computer tablets, and other high-throughput wireless devices whose communication capabilities are comparable to those of the WAP. The IEEE 802.11ax standard integrates Orthogonal Frequency Division Multiple Access (OFDMA) into the WAP or station capabilities. OFDMA allows the WAP to communicate simultaneously with multiple stations on the downlink within discrete frequency ranges identified as resource units.

[0009] The IEEE 802.11n and 802.11ac standards support increasing levels of complexity in signal processing required for fully compliant WLAN nodes, including beamforming capabilities for focusing user data communications. MIMO sounding is performed in order to characterize the multipath communication channel between the WAP and each station. Explicit sounding specified in the IEEE 802.11n and 802.11ac standards involves transmitting a known sequence of packets from the WAP to each associated station, which then processes the sequence of packets to perform measurements and calculations to generate a detailed probe response from the station for characterizing the communication channel between the WAP and itself. WAPs traditionally use explicit probe responses to focus their MIMO antennas in a manner that improves either or both of the signal strength at the station or the downlink throughput to the MIMO antennas.

[0010] As the variety and number of stations on wireless networks increases, there is an increasing need for an improved probing process that can effectively coordinate communication services to a greater number of devices while reducing the transmission overhead of probing and the processing overhead required to probe stations. Summary of the invention

[0011] Among other benefits, methods and systems employing a sounding protocol that includes a request for a valid communication sequence also improve bandwidth for a sounding session and reduce processing required on a beamforming receiving end. In one example, a transmitter determines a sounding control schedule for one or more receivers, transmits a sounding trigger to the one or more receivers based on the sounding control schedule, receives at least one dedicated training signal from the one or more receivers in response to the sounding trigger, and for each received dedicated training signal, the transmitter estimates forward channel state information (CSI) derived based on the dedicated training signal from the associated receiver.

[0012] Exemplary implementations include methods and systems for operating a wireless transceiver, the methods and systems comprising: for each of the received dedicated training signals, in response to a sounding trigger, transmitting a sounding trigger to one or more beamforming receivers via a forward channel, receiving at least one dedicated training signal from the one or more beamforming receivers via a reverse channel. The method also includes estimating a forward CSI derived based on the dedicated training signal from the associated beamforming receiver, and a subsequent packet may be precoded with a precoding derived from the forward CSI for transmission to the associated beamforming receiver via the forward channel.

[0013] Exemplary implementations include methods and systems for a wireless transceiver device having a wireless local area network for supporting wireless communications, and the wireless transceiver device includes multiple antennas. The wireless transceiver device also includes multiple components coupled to each other to form a transmit chain and a receive chain; and a requester module circuit, the requester module circuit is used to transmit a sounding trigger via a forward channel to request multiple dedicated training signals from one or more beamforming receivers, and these dedicated training signals will be processed for estimating forward CSI to transmit subsequent packets to the associated beamforming receivers.

[0014] An exemplary implementation includes a method and system for operating a wireless transceiver, including: for each received dedicated training signal, transmitting a sounding trigger to one or more beamforming receivers via a forward channel in response to a sounding trigger, and receiving at least one dedicated training signal with timing information from one or more beamforming receivers via a reverse channel in response to the sounding trigger. The method also includes estimating forward channel state information derived based on the dedicated training signal from the associated beamforming receiver; and wherein subsequent packets are precoded with a precoding derived from the forward CSI for transmission to the associated beamforming receiver via a forward channel, and a packet transmission timestamp and a packet reception timestamp are determined based on the timing information. Other embodiments of this aspect include corresponding communication protocols, networking systems, apparatuses, and computer programs recorded on one or more computer storage devices, each computer program configured to perform the actions of the method.

[0015] The method and system are implemented using one or more networked devices and / or systems. After reviewing the following detailed description and the accompanying drawings, other features and advantages of the inventive concept will become more apparent to those of ordinary skill in the art. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The structure and operation of the exemplary implementations will be understood from the following detailed description and accompanying drawings, wherein like reference numerals represent like parts, and wherein:

[0017] Figure 1A -B shows an existing example of WLAN channel sounding and beamforming communication.

[0018] Figure 2A -D shows an example of an existing probe and grouping graph.

[0019] Figure 3 A flow chart of an exemplary requested sounding beamformer process according to an exemplary implementation is shown.

[0020] Figure 4A A diagram of an exemplary probe requestor system is shown according to an exemplary implementation.

[0021] Figure 4B A diagram illustrating an exemplary probe trigger frame according to an exemplary implementation is shown.

[0022] Figure 5A -G shows an exemplary sequence of requested probes according to various exemplary implementations.

[0023] Figure 6 A flow chart of an exemplary requested sounding beamforming receive-side process according to an exemplary implementation is shown.

[0024] Fig. 7A -B shows an example of a probe of a request with timing feedback according to an exemplary implementation.

[0025] Fig. 8A -C shows an example of a sounding requested by another beamformer according to an exemplary implementation.

[0026] Fig. 9 A diagram of an exemplary networked device is shown according to an exemplary implementation. DETAILED DESCRIPTION

[0027] The following detailed description provides more details of the drawings and exemplary implementations of the present application. For clarity, the figure numbers and descriptions of redundant elements between the drawings are omitted. The terms used throughout the specification are provided as examples and are not intended to be limiting.

[0028] The conventional explicit sounding method begins with a beamformer (e.g., access point, transmitter, etc.) sending a pair of packets having an announcement frame and a dedicated training signal (e.g., a null data packet announcement (NDPA) followed by a null data packet (NDP)) to a beamformed receiver (e.g., station, client, receiver, etc.) so that the beamformed receiver can measure the received dedicated training signal to obtain characteristics of the forward communication channel (e.g., from the beamformer to the beamformed receiver). The beamformed receiver then conventionally generates a detailed sounding feedback payload back to the beamformer. The beamformer conventionally uses the returned sounding feedback to determine precoding that can be used for subsequent transmissions to the beamformed receiver. The beamformer uses the sounding feedback to improve subsequent transmissions.

[0029] In the complex multipath channel environment encountered by multiple-input multiple-output (MIMO) transmission, the feedback of the link channel matrix consumes a lot of air time, because a certain amount of data must be transmitted to characterize the multipath channel, and the low modulation and coding scheme (MCS) for transmitting conventional detailed sounding feedback consumes a lot of network resources. Therefore, each explicit sounding consumes precious air time of the network.

[0030] Since explicit sounding uses the sounding feedback of the forward channel to determine the precoding of the forward channel, explicit sounding is generally more accurate than estimating the forward channel based on the reverse channel as in implicit sounding. However, explicit sounding generally requires additional overhead, and the sounding feedback received from the beamformer receiver may be quite large, thus reducing the availability of air time for other transmissions.

[0031] Conventional implicit sounding approaches begin with a beamformer opportunistically sending packets to a beamformer so that the beamformer can measure the received packets to determine characteristics of the reverse channel information (e.g., from the beamformer to the beamformer), which are then used to attempt to estimate the forward channel back to the beamformer. Conventional implicit sounding, however, cannot manage sounding between several beamformer receivers in an effectively coordinated framework. For example, because the beamformer receiver controls the initiation of the sounding process in conventional implicit sounding approaches, the beamformer cannot update the CSI when data communication is degraded. Furthermore, a beamformer receiver in an implicit sounding approach is only interested in its own sounding process and cannot consider the sounding needs of other sites or network resources over time.

[0032] As the variety and number of nodes on wireless networks increase, there is an increasing need for improved sounding protocols that can effectively coordinate communication services to a larger number of devices while reducing the transmission overhead from sounding and the processing overhead of sounding required by client nodes (e.g., beamforming receivers).

[0033] Various aspects of the exemplary implementations described herein relate to systems and methods for a requested sounding frame that is initially initiated by a beamformer, minimizes the processing resources required by a beamformer receiver, and can coordinate multiple sounding sequences between several beamformer receivers. The requested sounding frame provides improved transmission overhead for sounding and reduces the sounding processing overhead required by the beamformer receiver. In the exemplary implementations described herein, the beamformer transmits a sounding trigger to request a dedicated training signal frame from the beamformer receiver. A sounding trigger is a packet sent by a transmitter to at least one target station that instructs the station to send one or more dedicated training signals to the transmitter. A single sounding trigger can instruct a station to send multiple dedicated training signals and / or instruct a scheduler to send dedicated training signals and other configurable parameters related to the dedicated training signals or their transmission. A single sounding trigger can also instruct multiple stations to send multiple dedicated training signals.

[0034] A dedicated training signal is a packet sent by a beamformer receiver to a beamformer that does not require a payload. The transmitted dedicated training signal can be processed to estimate the channel information between the sender and the receiver. The beamformer receiver processes the sounding trigger and responds with one or more dedicated training signals to be sent at coordinated times based on the instructions indicated by the sounding trigger.

[0035] The beamformer may receive multiple responses to a single sounding trigger without additional prompting to the beamformer receiving end. The sounding trigger may include additional instructions for the response and does not require the beamformer to send an announcement packet with the sounding trigger or to prompt for additional dedicated training signals. The beamformer receiving end responds to the sounding trigger with one or more dedicated training signals based on the instructions accompanying the trigger. Dedicated training signals require significantly less overhead than traditional sounding feedback.

[0036] Exemplary aspects of the solicited sounding framework include an efficient sounding sequence between an access point and one or more stations by reducing the number of transmissions to initiate sounding and reducing the amount of bandwidth or air time used to determine CSI for a forward channel compared to explicit sounding.

[0037] In a requested sounding frame, a beamformer receiver (e.g., a station, a receiver, etc.) sends a dedicated training signal to a beamformer (e.g., an access point, a transmitter, a transceiver station, etc.), which dedicated training signal can be processed to estimate reverse channel information about the channel in the direction from the beamformer receiver to the beamformer. The beamformer measures the received dedicated training signal to determine characteristics of the reverse channel information (e.g., from the beamformer receiver to the beamformer), which characteristics are then used to attempt to estimate the forward channel back to the beamformer receiver.

[0038] The solicited sounding framework has improved performance and efficiency compared to traditional explicit sounding and traditional implicit sounding. For example, the solicited sounding framework uses a single sounding trigger instead of requiring the beamformer to send multiple packets (e.g., NDPA and NDP) and hints. In addition, the dedicated training signal allows the beamformer to respond with minimal processing and bandwidth without the need to measure the channel, generate detailed sounding feedback, and transmit a large amount of detailed sounding feedback (e.g., compressed feedback reports) that can consume a lot of processing and network resources.

[0039] Furthermore, the solicited sounding framework allows a beamformer to initiate a sounding process and coordinate several dedicated training signals from multiple beamformed receivers over a period of time without sending several prompts or waiting for the beamformed receivers to opportunistically send packets. Additional aspects of the solicited sounding framework as discussed herein include coordinated sounding for several receivers with different capabilities, configurable sounding characteristics, integrated ranging capabilities, etc.

[0040] In one exemplary implementation, the wireless transceiver transmits a sounding trigger to one or more beamformer receivers via a forward channel in response to the sounding trigger, and receives at least one dedicated training signal from the one or more beamformer receivers via a reverse channel. For each of the received dedicated training signals, the transceiver estimates a forward CSI derived based on the dedicated training signal from the associated beamformer receiver to improve the transmission of subsequent communications of data to the associated beamformer receiver (e.g., precoded with a precoding derived from the forward CSI for transmission to the associated beamformer data packet via the forward channel).

[0041] The requested sounding framework achieves improved data communication quality by instructing the beamforming receiver to send multiple dedicated training signals over time without additional prompts, so that the beamformer can use the multiple dedicated training signals to re-sound the link with the updated CSI. In addition, the beamformer can send an updated sounding trigger to maintain a coordinated sounding sequence with one or more beamforming receivers, thereby effectively maintaining a communication link within the network. In one example, the beamformer sends another sounding trigger in response to detecting a change in transmission quality, network resources, or performance of one or more of the beamforming receivers. For example, when data communication of one or more of the beamforming receivers is degraded, the beamformer can send another sounding trigger to update the sounding interval or training signal format indicated by the previous sounding trigger.

[0042] In other exemplary implementations, the efficiency of the requested sounding frame can be used to streamline or support other networking applications in addition to sounding (e.g., motion tracking, building automation, etc.) In one example, the transmission between the beamformer and the beamformed receiver of the requested sounding frame can be adapted to effectively synchronize timing, ranging functions, etc. between sites.

[0043] Figure 1A -B shows an existing example of WLAN channel sounding and beamforming communication. Figure 1A Channel sounding with intermittent probe packets sent from a WAP identifying one or more site nodes from which existing probe feedback is requested is shown. A conventional probe packet includes multiple elements, including an announcement packet with a probe packet (e.g., an NDP probe packet). The response to each intermittent probe packet from a receiving site node contains detailed information quantifying the characteristics of the channel between the receiving site node and the site node. The transmitter processes the detailed information. Whether sent from a device with a single antenna or multiple antennas, the probe packet exhibits RF signal strength to allow the receiving device to identify link channel characteristics.

[0044] exist Figure 1A , WAP 102 is shown establishing communication link 120 and communication link 140 with wireless site node 108 and wireless site node 112 within location 100, respectively. Each link pair exchanges capabilities (e.g., 122A-B on link 120 and capability exchange, 142A-B on link 140). During this exchange, the number of antennas, number of streams, encoding, and beamforming support capabilities of each device are exchanged. Next, an initial explicit probe request and response occurs, 122C-D on link 120 and 142C-D on link 140. The probe packets are sent using radio frequency (RF) signal strength 104. Upon receiving the probe packets, the receiving station determines the changes in amplitude and phase of the probe transmission that caused the link channel, such as fading, attenuation, and phase shift, and communicates indicia of these channel characteristics as a detailed probe feedback response packet 122D. As shown in 142D, they are returned to the WAP where they are immediately used to establish beamforming for subsequent data communications, such as Figure 1B shown.

[0045] The IEEE 802.11n and 802.11ac standards support increasing levels of complexity in the signal processing required of a fully compliant WLAN node, including beamforming capabilities for focusing user data communications. One of the many capabilities of a fully compliant WLAN node under either of these standards is the ability to focus the signal strength of transmitted communications to a receiving device. Doing so requires multiple antennas and a means for individually controlling the phase and amplitude of the communication signals transmitted thereon. A baseband component of the WAP or station, known as a spatial mapper, takes as input the individual communication streams for each antenna, along with a steering matrix (also known as a beamforming matrix) determined during a previous channel sounding, such as the beamforming matrix. Figure 1A The steering matrix contains complex coefficients corresponding to discrete phase and amplitude adjustments to the communication stream for each antenna, which provide the desired focused signal strength to the composite signal of the signals transmitted from all antennas. The steering matrix for subsequent transmissions is derived from the previous detection, as shown in Figure 1A shown.

[0046] exist Figure 1B , the WAP is shown using the sounding feedback to establish subsequent data communications with its link partners (e.g., station 108, station 112). Based on the capabilities supported by the transmitter and receiver, the detailed sounding feedback is used to establish subsequent beamformed data communications. Beamforming improves received signal strength and improves the received signal strength by using the CSI obtained in the detailed sounding feedback response packet (see, e.g., Figure 1A 122D, 142D), achieved by independent changes in the phase and / or amplitude of the signal transmitted from each of the transmit antennas, which collectively direct the transmit power coverage area to the intended recipient site.

[0047] A detailed probe feedback response packet is typically received in response to each probe packet. 0 105A is shown where WAP 102 uses multiple antennas to beamform downlink data communication packet 142E on link 140 to station 112. Subsequently, at time t 1 1. WAP 102 is shown beamforming 105B downlink data communication packet 122E on link 120 to station 112.

[0048] Figure 2A -D shows an existing example of a probe and grouping graph. Figure 2AAn existing sounding diagram is shown. The wireless communication protocol specifies that the packet header includes various preamble fields with a known sequence to allow the receiving station to synchronize the reception with the packet boundary to determine the received channel. The typical operation of the WAP includes a transmitter and receiver sounding sequence, which starts with a pair of packets (e.g., announcements and NDPs) that can be sent periodically (e.g., at 100 millisecond intervals) to start the sounding sequence, followed by a short inter-frame space (SIFS) and a sounding response. During the sounding sequence, one or more downstream links or upstream links are sounded to determine their channel characteristics, and the beamforming matrix of each link subjected to sounding is determined using the CSI in the feedback from the sounding. The sounding is performed on a per-link basis and can also be a downlink sounding or an uplink sounding. The sounding feedback for each link is different. During the contention-based interval, carrier sense multiple access (CSMA) is used as a medium access control (MAC) method to allow any station to gain control of the channel and send uplink user data communications thereon to the transmitter 202.

[0049] The conventional explicit detection protocol causes the transmitter 202 to send a detection packet with an announcement frame 211, a null data packet (NDP) 212 frame and a response frame, such as Figure 2A and 2B 200A, 200B and 201C. A conventional sounding packet includes a pair of packets, wherein the NDPA 211 packet precedes the NDP 212 packet and identifies the receiving site 208 that is requested to share the channel analysis (e.g., CSI) performed by the beamforming receiving end (e.g., receiving site 208) with the beamformer (e.g., transmitter 202).

[0050] In this pair of packets, the NDPA 211 indicates which stations will respond to the next NDP 212 sounding frame and describes the NDP frame size. After the NDPA 211, the transmitter 202 sends the sounding NDP 212 as a broadcast to be processed by the identified receiving station 208. In response to receiving the NDP 212 broadcast, the identified beamformer receiver performs a series of steps to measure the RF channel characteristics, process and generate a steering matrix with the channel measurement results as part of the detailed sounding feedback response packet 250. After the beamformer receiver receives the station 208 to complete the series of steps, the station 208 responds to the NDPA 211 and NDP 212 with a detailed sounding feedback response packet 250.

[0051] Figure 2BThe prior art sounding diagrams 200B and 201B are explicit sounding for sequential sounding and data communication. The explicit sounding of the link channel between the transmitter 202 and the station 208 and between the transmitter 202 and the station 209 are shown in 200B and 201B. The sounding sequence includes the transmitter 202 sending the pair of sounding packets NDPA 211 and NDP 212, and in response, the target station 208 (after a lot of processing 260) sends back a compressed detailed sounding feedback response packet 250A. The transmitter must then send a report polling packet 213 in time to prompt the next station 209, from which the generation of detailed sounding feedback is requested.

[0052] The header of the NDP packet 212 contains a ubiquitous preamble field used for channel estimation, which in the case of the IEEE 802.11ac standard is identified as Figure 2C The VHT-LTF field (e.g., channel estimation or sounding field) contains a long training sequence used for MIMO channel estimation by the receiver site 208. Each receiving site 207, 208, 209 is then required to determine the corresponding beam steering matrix required to adjust the phase and amplitude for subsequent MIMO transmissions of the transmitter 202 in order to update the received signal strength at the receiving site.

[0053] Each beamforming receiving end site 207, 208, 209 is required to perform a significant amount of processing of the NDP 260 to determine detailed sounding feedback based on the matrix by performing a singular value decomposition (SVD) on the H matrix for each subchannel or tone which requires a significant amount of processing resources (e.g., power, time, processor cycles, memory, etc.) to complete. The signal-to-noise ratio (SNR) matrix is ​​derived by scaling the sigma L matrix of the SVD. Each site then waits for the transmitter to send another packet (e.g., a report poll 213) to prompt a response before the beamforming receiving end site sends a single detailed sounding feedback in response to each report poll 213. That is, the first target site 208 responds with a detailed beamforming feedback packet 250B containing CSI (e.g., payload) only when prompted. If the receiving site is IEEE 802.11n compliant, the detailed feedback is in the form of a link channel matrix H. If the receiving station is IEEE 802.11ac compliant, the detailed feedback is in the form of the actual integrated beam steering matrix V and the per-tone diagonal matrix SNR. Any remaining stations targeted by the initial sounding respond with the beam steering matrix for their own link when required to do so by the Report Poll 213. The next station 209 then responds with a compressed Detailed Sounding Feedback Response Packet 251B. After the sounding, communication resumes and downlink communication of user data is sent on the sounded link or links. Since each station 207, 208, 209 sends detailed sounding feedback in response to each transmitter request, considerable bandwidth is consumed to maintain a large number of stations with frequent sounding sequences.

[0054] In response to each additional sounding packet 211 and 212, the beamformer receiver 209 may send an additional detailed beamforming feedback packet 251B, 252B, etc. In some approaches, the beamformer receiver 209 may send an additional detailed beamforming feedback packet 251B, 252B in response to each prompt (e.g., report poll 213).

[0055] User data packets 266 (e.g., medium access control (MAC) service data units (MSDUs) or protocol data units (MPDUs)) are sent using precoding based on the associated beamforming matrix. Transmitter 202 resumes sending user data packets 266 on the links that have been probed. The time and overhead required to send detailed probe feedback response packets 250A and 251B consumes significant processing and transmission resources.

[0056] Figure 2C is an existing packet diagram of a transmitter packet with a preamble field for channel estimation. Figure 2CThe header includes a packet 240 and a corresponding symbol interval (SI) required to transmit each field. The header includes a legacy portion containing L-STF, L-LTF, and L-SIG fields, and a very high throughput portion containing VHT-SIGA, VHT-STF, VHT-LTF, and VHT-SIGB fields. The payload portion does not contain user data. The traditional (L), long (LTF), and short (STF) training and signal (SIG) fields are compatible with sites that only support IEEE 802.11n or earlier standards. The remaining signal and training fields are intended for very high throughput (e.g., devices that comply with IEEE 802.11ac). The VHT-SIGA field contains information about the number of MCS and sounding streams. The VHT-STF field is used for automatic gain control (AGC). The VHT-LTF field (e.g., channel estimation) includes a long training sequence used by the receiver for MIMO channel estimation.

[0057] Figure 2D 202 and one or more stations 208, 209. Access points and stations may be transceivers that include both a transmitter and a receiver that are combined and share common circuitry or a single housing. Access points and stations may also be transmitter-receivers that have separate circuitry between the transmit and receive functions. A beamformer typically includes multiple antennas for the transmitter and receiver, and a beamformer receive may work with a single antenna or multiple antennas.

[0058] In the example where the access point transmitter 202 is a beamformer sounding beamforming receiving end site 209, the sounding channel can be described as having both a forward channel 220 from the beamformer access point 202 to the beamformed receiving end site 209 and a reverse channel 221 from the beamformed receiving end site 209 to the beamformer access point 202. Figure 2A and 2B As shown, the beamformer access point 202 conventionally sends a pair of sounding packets with an NDPA announcement 211 and an NDP sounding 212 via a forward channel 220 that is received by a beamformed receiving end station 209. Conventionally, the beamformed station 209, after processing the pair of sounding packets, then sends detailed sounding feedback 250A, 250B, or 251B via a reverse channel 221.

[0059] Multiple stations 208, 209 may also detect each other, such as in a mesh network. In an example where station 208 is a beamformer-sounding beamforming receiving end station 209, the sounding channel may be described as having both a forward channel 230 from the beamformer station 208 to the beamforming receiving end station 209 and a reverse channel 231 from the beamforming receiving end station 209 to the beamformer station 208. Thus, the beamformer station 208 sends a pair of sounding packets having an NDPA announcement 211 and an NDP sounding 212 via the forward channel 230 received by the beamforming station 209. Conventionally, the beamforming receiving end station 209, after processing the pair of sounding packets, then sends detailed sounding feedback via the reverse channel 231.

[0060] Conventional explicit sounding requires the beamformer to send multiple packets to the beamformed receiver, which must then process each of the multiple packets to generate detailed sounding feedback and then return the detailed sounding feedback when prompted. Multiple packets consume air time in the forward channel 220, preventing the transmitter from using these communication resources to deliver actual user data to other stations. Detailed sounding feedback consumes a large number of processing cycles (e.g., 260), power at the beamformed receiver, and bandwidth of the reverse channel 231. Regular sounding sequences for beamformed receiver stations with limited resources can reduce the practicality and effectiveness of such stations. In addition, for networks with many stations, sounding with multiple packets and detailed sounding feedback wastes bandwidth and interferes with access points, making it impossible to effectively coordinate services to meet growing station demands. In addition, additional detailed sounding feedback packets are sent in response to receiving additional prompts from the beamformer.

[0061] Figure 3 A flow chart of an exemplary requested sounding beamformer process according to an exemplary implementation is shown. The requested sounding framework allows a beamformer to initiate a requested sounding process in a coordinated scheme for several beamforming receiving end sites with different capabilities and configurable sounding characteristics. The requested sounding framework also coordinates the beamforming receiving end sites to automatically update the beamformer with information to accurately precode user data without requiring the beamformer to send repeated update requests or update prompts.

[0062] The beamformer process may begin at step 310 to determine sounding controls for one or more beamformer receivers. In an exemplary implementation, the sounding controls may include sounding scheduling instructions, training options, and site information, as discussed with reference to FIGS. 4-8. Since the requested sounding frame is initially initiated by the beamformer, it may coordinate multiple sounding sequences among several beamformer receivers and reduce the sounding processing overhead required by the beamformer receivers. The requested sounding frame provides improved transmission overhead for sounding and requires minimal processing resources by the beamformer receivers.

[0063] The sounding schedule and training options may be based on communication parameters, such as capabilities of the beamformed receiver (e.g., beamforming, MIMO, etc.), traffic type (e.g., web browsing, video streaming, video conferencing, etc.), or positioning parameters (e.g., mobility, dwell time, etc.). In an exemplary implementation, the sounding schedule enables the beamformer to instruct the beamformed receiver to send multiple dedicated training signals at predetermined sounding intervals in a coordinated manner and avoid sending multiple sounding trigger requests. The beamformed receiver receives the sounding trigger with the sounding instruction and provides an initial dedicated training signal response that does not require payload or significant processing by the beamformed receiver. The beamformed receiver may store the instructions and execute the schedule to provide additional dedicated training signals without receiving additional sounding triggers or prompts. For example, the beamformer may determine that the sounding control includes a sounding schedule with a short time interval for a receiver that previously received video conferencing traffic data.

[0064] At 320, the beamformer process transmits a sounding trigger to one or more beamformed receivers based on the sounding control. For example, a single sounding trigger can be a null data packet poll frame that is not preceded by an announcement frame. Unlike traditional explicit sounding techniques, solicited sounding enables the beamformer to trigger repeated information based on a single sounding trigger instead of NDPA and NDP.

[0065] At 330, the beamformer process receives at least one dedicated training signal from one or more beamformed receivers in response to the sounding trigger. In the requested sounding, the beamformed receivers do not measure channel information from the received sounding trigger. The one or more dedicated training signals sent by the beamformed receivers are triggered by the sounding trigger, but the dedicated training signals do not require measurements associated with the transmission of the sounding trigger. For example, the dedicated training signal may be a null data packet without a sounding data payload.

[0066] At 340, for each received dedicated training signal, the beamformer process performs steps 350 and 360 to estimate forward channel state information. At step 350, the beamformer process calculates the CSI of the reverse channel by measuring the received dedicated training signal. At 360, based on the characterization of the front-end parameters of the transmitter, the beamformer process derives the CSI of the forward channel from the CSI of the reverse channel. In an exemplary implementation, the beamformer process may use the estimated forward CSI at 370 to transmit a subsequent packet using a precoded packet with a precoding derived from the estimated CSI. The beamformer process repeats at least steps 350 and 360 for each received dedicated training signal. Therefore, the requested sounding frame requires less beamforming receive-end processing and less bandwidth than conventional sounding methods.

[0067] Figure 4A A diagram of an exemplary sounding requester system according to an exemplary implementation is shown. The requester system 410 includes a trigger generator 415, a scheduler 420, a training options module 430, and a beamformer receiver manager 440 for transmitting a sounding trigger to one or more beamformer receivers. In one exemplary implementation, the trigger generator 415 can create a sounding trigger that includes sounding controls, such as sounding scheduling instructions, training options, and site information for one or more receivers. For example, the training options used by the beamformer receiver to format a dedicated training signal can include repeated symbols, fractional bandwidth, multiple bits, etc.

[0068] The trigger generator 415 uses the beamforming receiver manager 440 to determine the site information for the sounding trigger, including a list of receivers that respond to the sounding trigger. The beamforming receiver manager 440 can determine the characteristics of the site to receive the sounding trigger from the transmitter. In some examples, the site can be associated with the transmitter so that a successful handshake or authentication process has been attempted or successfully completed. The beamforming receiver manager 440 can also infer characteristics or assign identifiers to sites that are not associated or authenticated with the transmitter. In some specific implementations, the beamforming receiver manager 440 uses the data repository 402 or the analyzer module 470 to track or predict the characteristics of the site. For example, the beamforming receiver manager 440 can determine the site identifier (ID), site capabilities, site type, business / service type, location information, predicted dwell time, etc. In addition, the beamforming receiver manager 440 can use the captured MAC address information to determine the identifier or assign the identifier to the site. Using the beamforming receiver manager 440, the trigger generator 415 can include instructions for different receivers in the sounding trigger.

[0069] In an exemplary implementation, the trigger generator 415 may include different scheduling instructions for different receivers in the sounding trigger. The beamforming receiver manager 440 performs functions for coordinating and updating the operations of other modules of the requester system 410. For example, the beamforming receiver manager 440 works with the scheduler 420 to generate a list of one or more receivers associated with the sounding trigger.

[0070] The scheduler 420 may generate scheduling instructions for various target receivers or groups of receivers to provide dedicated training signals in a coordinated manner. For example, the scheduler 420 may generate scheduling instructions for different receivers to respond simultaneously in response to detection triggers at different spatial streams. As further discussed herein with reference to FIG. 5 , the synthesizer system 410 may create various scheduling configurations.

[0071] In an exemplary implementation, the trigger generator 415 may include scheduling instructions for the sounding triggers for the receiver group and / or allow the receivers in the group to determine coordinated response times or intervals. The beamforming receiver manager 440 may identify the group of receivers, and the scheduler 420 may schedule the group of receivers according to the present disclosure. Figure 3 -5 to generate the sounding instructions for the group.

[0072] In an exemplary implementation, the trigger generator 415 may include in the sounding trigger training options for formatting a dedicated training signal by one or more receivers. The beamforming receiver manager 440 may operate with the training options module 430 to generate instructions for different receivers to respond to the sounding trigger with a dedicated training signal in a specific format or communication mode (e.g., repeated symbols, spatial streams, partial bandwidth, multiple bits, etc.). The training options module 430 may also configure a set of training options in the sounding trigger based on characteristics of the transmitter, observed network behavior or performance, environmental factors, feedback quality, etc.

[0073] The trigger generator 415 generates a sounding trigger for one or more receivers to request a dedicated training signal with minimal overhead. In response to a single sounding trigger, the requestor system 410 may receive multiple dedicated training signals from a single receiver and / or multiple different receivers.

[0074] The requester system 410 includes a front-end controller 445, a dedicated training signal tracker module 450, a reverse channel CSI module 455, a calibration module 460, and a precoder 465 for processing received dedicated training signals.

[0075] The front-end controller 445 and the dedicated training signal tracker module 450 may operate together with the beamforming receiving end manager 440 to process a plurality of dedicated training signals received simultaneously. For example, the front-end controller 445 may simultaneously receive a plurality of dedicated training signals in different spatial streams, and the dedicated training signal tracker module 450 may arrange the received dedicated training signals and associate them with a site profile or site information based on information from the beamforming receiving end manager 440.

[0076] The dedicated training signal tracker module 450 processes the received dedicated training signals to measure channel information from each dedicated training signal, and the reverse channel CSI module 455 calculates the CSI of the reverse channel based on the measured dedicated training signal information. The calibration module 460 derives the forward CSI of the forward channel from the reverse channel CSI using the characteristics of the transmitter from the front-end controller 445. The characteristics of the transmitter from the front-end controller 445 may be based on the specific hardware or software configuration of the transmitter, such as manufacturing process differences, design parameters, RF hardware and frequency band to antenna transmission time or delay, delay differences between multiple transmission chains, etc. The precoder 465 then uses the precoding derived from the forward CSI for subsequent transmission to the associated receiver via the forward channel.

[0077] An exemplary implementation of the synthesizer system 410 may also include an analyzer 470, a mapper 475, and a timer module 480. The analyzer 470 may track the traffic volume with each station to generate historical information for predicting the best configuration of the probe trigger. For example, based on the historical usage schedule or movement of the station, the analyzer 470 may indicate to the scheduler 420 the best time interval for scheduling repeated dedicated training signals in response to a single probe trigger.

[0078] The mapper 475 can optimize the sounding communication with stations of different capabilities. For example, the mapper 475 can coordinate with the front-end controller 445 to receive a dedicated training signal from a receiver supporting multi-user MIMO (MU-MIMO), a beamforming receiver, etc. The timer 480 supports ranging operations with minimal overhead by utilizing the requested sounding trigger and the dedicated training signal response. For example, the timer 480 can be used with the training option module 430 to request a timestamp feedback with a dedicated training signal from the receiver to perform the ranging operation, thereby avoiding or reducing additional triggers or requests from the transmitter.

[0079] Figure 4BA diagram of an exemplary probe trigger frame according to an exemplary implementation is shown. The exemplary probe trigger 411 includes an initiator 416, which is a preamble for instructing the receiver to respond with a dedicated training signal. The probe trigger 411 is a single frame that is transmitted and includes at least the preamble initiator 416 without any announcement packets. That is, the probe trigger 411 is not part of a pair of packets or is preceded by an announcement packet (e.g., an NDPA packet).

[0080] The probe trigger 411 may include schedule information 421 created by the scheduler 420, which, for example, allows repeated responses to a single probe trigger 411. Types of schedule information 421 may include time interval 421A, probe position 421B, packet length 421C, terminator 421D, and the like.

[0081] The time interval 421A of the schedule 421 indicates how often the beamformer receiver transmits the dedicated training signal after receiving the single sounding trigger 411. For different beamformers receiving the single sounding trigger 411, the synthesizer system 410 may configure the time interval 421A to be static or dynamic based on a time period, network conditions, etc. For example, the static time interval 421A of the schedule 421 may instruct the beamformer receiver to repeat the transmission of the dedicated training signal consistently according to a time frame (e.g., every 100 microseconds). The dynamic time interval 421A of the schedule 421 may instruct the beamformer receiver to repeat the transmission of the dedicated training signal in a burst within the time frame or intermittently according to a timing factor, condition, specific channel activity, etc.

[0082] The detection position 421B may be used to indicate when the beamforming receiver will send a dedicated training signal based on a relative position or a defined position. The detection position 421B at which the beamforming receiver sends the dedicated training signal may be related to one or more other beamforming receivers that respond to the detection trigger 411 (e.g., order, position, rank, group, time slot, etc.). For example, the detection trigger 411 may be sent to a list of beamforming receivers, and the detection position 421B indicates a sequence for each beamforming receiver in the list to transmit the dedicated training signal. The beamforming receiver may repeatedly send the dedicated training signal by restarting the sequence without receiving another detection trigger 411. In another example, the detection position 421B indicates a coordinated time position (e.g., based on a time scale, a reference time, etc.) of each of the beamforming receivers to repeatedly send the dedicated training signal in groups or at different times without receiving another detection trigger 411.

[0083] In some implementations, the sounding position 421B instructs the beamformer receiver to repeatedly transmit the dedicated training signal by listening to the channel according to the packet length 421C of the sounding trigger 411. For example, the beamformer receiver can monitor the channel to detect a preamble from another beamformer receiver or count the number of transmissions heard from other beamformer receivers, determine the previous beamformer receiver based on the sounding position 421B, and calculate the time of transmission after the previous beamformer receiver according to the packet length 421C.

[0084] The schedule 421 may include a terminator 421D to indicate or signal one or more of the beamforming receivers to stop or pause sending additional dedicated training signals. In some implementations, the terminator 421D is sent with the first detection trigger 411 to indicate when one or more of the beamforming receivers stop or pause sending dedicated training signals. For example, the terminator 421D may indicate multiple dedicated training signals to be sent without receiving another detection trigger. The terminator 421D may also indicate that the sending of dedicated training signals is suspended after a period of time or condition (e.g., the schedule expires). Other implementations may include a second detection trigger 411 with a terminator 421D that signals to stop or pause sending dedicated training signals. The detection trigger 411 may include a terminator 421D for each target beamforming receiver, a subset of the target beamforming receivers, or all responding beamforming receivers. In another example, the detection trigger 411 may include training options 431, which are configured by the training options module 430 to, for example, instruct the receiver how to format or customize the dedicated training signal. The types of training options 431 may include precision parameters 431A, format 431B, timing options 431C, spatial streams 431D, etc.

[0085] For example, the precision parameter 431A may indicate how often a symbol is repeated in a VHT-LTF for averaging at the receiver. In one example, the timing option 431C may indicate a measured arrival time of incoming packets and a measured departure time of outgoing packets. The training options 431 may include a spatial stream 431D configuration for use with a receiver supporting MU-MIMO. Other exemplary training options 431 may include configurable format 431B elements as understood in the art.

[0086] The sounding trigger 411 may also include site information 441 coordinated by the beamforming receiver manager 440 to enable, for example, multiple receivers to respond to a single sounding trigger 411. Types of site information 441 may include a site list 441A, a site identifier 441B, a MAC address 441C, a site capability 441D, and the like.

[0087] An exemplary implementation of requested probing as described herein may use a probe trigger 411 that includes an initiator 416 and that otherwise does not include any, some, or all of the scheduling information 421, training options 431, and / or site information 441 described herein.

[0088] Figure 5A -G shows an exemplary sequence of requested probes according to various exemplary implementations. Figure 5A An exemplary sequence 500A and 501A of a requested probe for a target station 508A is shown. The requested probe process may be initiated by the access point 502A to probe a channel for communicating with the station 508A. Figure 5A In the exemplary implementation shown in FIGS. 500A and 501A , the access point 502A initiates the requested probe by sending an NDP poll 510A as a probe trigger to identify the access point 502A and the target recipient site 508A.

[0089] In response to receiving the NDP poll 510A, the station 508A sends an NDP 550A to the access point 502A. The NDP 550A is sent within a first interval (e.g., a short interframe space (SIFS) or a portion of a SIFS) of the NDP poll 510A. The access point 502A reserves the channel during a predetermined response period for receiving a dedicated training signal. The NDP 550A response packet is an exemplary dedicated training signal without user data that can be processed to estimate reverse channel information in the reverse direction from the station 508A to the access point 502A. The access point 502A estimates the forward CSI using the reverse channel information derived based on the NDP 550A to determine a corresponding link matrix for adjusting the forward channel precoding (e.g., user data 566A) of subsequent MIMO transmissions by the access point 502A to the target station 508A.

[0090] Figure 5B An exemplary sequence 500B, 501B, and 503B of requested probe bursts according to various exemplary implementations are shown. In an exemplary implementation, the requested probe may include a separate probe triggering NDP poll 510B to request one or more dedicated training signals (e.g., NDP 550B, 551B, 552B) from a single station 508B, such as Figure 5B The beamformer may send an additional NDP poll 511B to update (eg, add, change, modify, cancel, etc.) instructions for a single station 508B indicated by a previous NDP poll 510B.

[0091] The requested sounding framework achieves improved data communication quality by instructing the beamformed receiver to send multiple dedicated training signals over time without additional prompts, so that the beamformer can use the multiple dedicated training signals to re-sound the link with updated CSI. In addition, the beamformer may send another sounding trigger to maintain a coordinated sounding sequence with one or more beamformed receivers, thereby effectively maintaining a communication link within the network. For example, the beamformer may send another sounding trigger to take into account changes in transmission quality, network resources, and performance of one or more beamformed receivers. In one example, as data communication degrades, the beamformer may send another sounding trigger to update the sounding interval or training signal format indicated by the previous sounding trigger.

[0092] In another exemplary implementation, the requested probe burst may include separate probe-triggered NDP polls 510B and 511B to request one or more dedicated training signals (e.g., NDPs 550B, 551B, 552B) from different stations 508B, 509B, such as Figure 5B As shown in sequence 500B and sequence 503B. According to various exemplary implementations, the detection triggering NDP polls 510B and 511B may be sent to one or more sites 508B, 509B. That is, the NDP poll 510B may be directed to the first site 508B, and the NDP poll 511B may be directed to the second site 509B. In another example, the NDP poll 510B and the NDP poll 511B may be directed to both the first site 508B and the second site 509B. In addition, the NDP poll 510B may be directed to the first site 508B and the NDP poll 511B may be directed to both the first site 508B and the second site 509B. Alternatively, the NDP poll 510B may be directed to both the first site 508B and the second site 509B, and the NDP poll 511B may be sent to update the detection instructions of one of the sites (e.g., the first site 508B).

[0093] The requested probing process is initiated by the access point 502A to probe a plurality of different stations 508B, 509B using a plurality of probing triggered NDP polls 510B and 511B. Figure 5B In the exemplary implementation shown, the access point 502B initiates a solicited sounding by sending a first NDP poll 510B to the first station 508B, and receives a first NDP 550B within a first interval for sounding the first NDP poll 510B. After receiving the first dedicated training signal from the first station 508B, the access point 502B may initiate another solicited sounding by sending a second NDP poll 511B and receive a second NDP 551B from the second station 509B.

[0094] The first NDP poll 510B and / or the second NDP poll 511B may include a schedule for the corresponding station 508B and / or station 509B to send additional NDP 552B responses without receiving additional NDP polls. The access point 502B uses each received NDP 550B, NDP 551B, and NDP 552B to estimate the forward CSI derived based on each NDP for detecting the associated station 508B or 509B. Figure 5B In another example implementation shown, a first NDP poll 510B may be used to request one or more dedicated training signals from a target station 508B as a NDP 550B response. Based on the received NDP 550B, the access point 502B derives forward CSI of a forward channel from the reverse channel CSI according to characteristics of the RF front end of the transmitter, and precodes subsequent packets for transmission using the precoding derived from the forward CSI.

[0095] The NDP poll 510B may include instructions for the target site 508B to send additional NDPs without additional NDP polls. The access point 502B may also send another NDP poll 511B to the target site 508B to change (e.g., modify, replace, cancel, etc.) instructions indicated by a previous probe trigger (e.g., the first NDP poll 510B). The second NDP poll 511B may be used to update parameters for requesting one or more dedicated training signals indicated by a previous NDP poll 510B sent to one or more recipients.

[0096] Figure 5C An exemplary sequence of requested probes for a series of dedicated training signal responses is shown. In an exemplary implementation, the NDP poll 510C may include instructions for the target station 508C to send a series of NDPs 550C, 551C, 552C without sending additional NDP polls.

[0097] exist Figure 5C In the exemplary implementation shown, a first NDP 550C may be sent by a station 508C to an access point 502C as an initial response to an NDP poll 510C from the access point 502C. The target station 508C may send additional dedicated training signals NDP 551C and NDP 552C based on instructions included in the NDP poll 510C. In order to receive the additional NDP 551C and NDP 552C, the access point 502C may maintain a timer to anticipate when to expect additional dedicated training signals and reserve the channel.

[0098] For example, the NDP poll 510C may include instructions to coordinate with the target site 508C when to expect a series of NDPs 550C, 551C, 552C at fixed or variable intervals, time windows, based on satisfying a threshold condition, external measurement resources, predictions, etc. Thus, the access point 502C may receive a series of NDPs 550C, 551C, 552C based on a single NDP poll 510C.

[0099] Figure 5D An exemplary sequence of probes for requests to respond to a series of dedicated training signals from one or more stations 550D, 551D, 552D is shown. In an exemplary implementation, the NDP poll 510D may include instructions indicating a schedule for multiple different stations 507D, 508D, 509D to send multiple 550D, 551D, 552D without additional NDP polls. Figure 5D In the exemplary implementation shown, the NDP poll 510D may include a schedule indicating response intervals, probe locations, etc., when each of the stations 507D, 508D, 509D transmits an NDP 550D, 551D, 552D.

[0100] The NDP poll 510D is a probe trigger that identifies the access point 502 and the target receiving station 508 of the requested probe. In the case where the NDP poll 510D is sent to more than one station, the station 507D, 508D, 509D can use the order in which the receiving station is listed in the instruction from the probe trigger 510D to control the order or position for sending the NDP 550D, 551D, 552D. For example, the NDP poll 510D may include a list with the order or probe position of each station in the station 507D, 508D, 509D. The station 507D, 508D, 509D may repeatedly send the NDP 550D, 551D, 552D to the access point 502D according to the order or schedule until the schedule expires, a termination command is sent, a new NDP poll is received, or the station 507D goes offline.

[0101] For example, the scheduling instructions indicated by NDP poll 510D may assign site 507D to send a first NDP 550D within a SIFS relative to NDP poll 510D, assign site 508D to send another NDP 551D within a SIFS relative to the first NDP 550D, and assign site 509D to send a third NDP 552D within a SIFS relative to the second NDP 551D.

[0102] In another exemplary implementation, the NDP poll 510D may initiate multiple different stations 507D, 508D, 509D to send multiple NDPs 550D, 551D, 552D without additional NDP polls, wherein the different stations 507D, 508D, 509D determine when to send each of the NDPs 550D, 551D, 552D. For example, the NDP poll 510D may be received by multiple different stations 507D, 508D, 509D, and each station may monitor the network channel to detect a preamble of other dedicated training signals from other receivers in response to a sounding trigger.

[0103] In this example, station 507D may begin responding to NDP poll 510D with NDP 550D, and station 508D may monitor the network channel and listen to the preamble of NDP 550D. Station 508D may calculate the packet length of NDP 550D by listening to the preamble of NDP 550D. Based on the packet length, station 508D may determine when the channel will become available for the next transmission of access point 502D, and then transmit NDP 551D when the channel is available.

[0104] As another example, station 507D and station 508D may contend for the medium before sending an NDP. For example, station 507D and station 508D may each attempt to transmit, detect that the channel is busy, and wait a certain amount of time (e.g., a contention window) before attempting to transmit again. In response to first station 508D detecting that the channel is available, NDP 551D is transmitted, and station 507D waits another amount of time before attempting to transmit. Then, after the other amount of time, if second station 507D detects that the channel is available, NDP 550D is transmitted.

[0105] As described above, the NDP 550D, 551D, 552D responses are packetized as dedicated training signals without user data that can be processed to estimate reverse channel information in the direction from each of the sites 507D, 508D, 509D to the access point 502D. Then, for each received NDP 550D, 551D, 552D, the access point 502D estimates the forward CSI derived based on the corresponding NDP to determine the corresponding link matrix required to adjust the forward channel precoding of subsequent MIMO transmissions (e.g., user data 566) by the access point 502 to the associated target site.

[0106] Figure 5EAn exemplary sequence of probes for a request with a variable response schedule is shown. The access point 502E may send an NDP poll 510 to multiple different sites 507E, 508E, 509E or groups of sites and receive multiple NDPs (e.g., 550E, 551E, 552E) within a response window (e.g., a network allocation vector (NAV) 524).

[0107] The access point 502E may establish response window coordinates with stations that respond to the probe trigger to transmit non-responding stations and block them from attempting to transmit on the channel. For example, the NAV 524 provides a virtual carrier sensing mechanism to control network access by signaling stations on the network that a channel is unavailable or busy within a specified contention period. Stations that do not respond to the NDP poll 510E listen to the wireless medium and set their NAV using the duration field to indicate how long they must defer access to the medium.

[0108] The responding stations 507E, 508E, 509E may respond at different times (eg, T 1 、T 2 、T 3 etc.) to respond. The requested detection framework supports various scheduling schemes as described herein. For example, the NDP poll 510E may indicate a detection position relative to other receiver sites, and each site 507E, 508E, 509E may determine one or more response times based on the detection position to transmit one or more dedicated training signals at the calculated response time. As another example, the sites 507E, 508E, 509E may coordinate and sequentially send multiple NDPs 550E, 551E, 552E by determining the response time based on the packet length of the NDP. Each site 507E, 508E, 509E may monitor channel listening to detect the preamble of the NDP from another site in the site to determine the packet length of the NDP. Based on the determined packet length of the NDP, the second site 508E may calculate the response time T based on a reference time (such as the last detected NDP preamble). 2 .

[0109] Fig. 5F An exemplary sequence of probes for requests utilizing uplink MU-MIMO communications is shown. An access point with front-end RF functional parameters for uplink MU-MIMO communications splits the available bandwidth into separate individual streams (i.e., spatial streams) that equally share the medium. With uplink MU-MIMO, an access point can simultaneously receive different data from two or more sites over the same set of OFDM tones. A MU-MIMO access point is characterized by the front-end parameters of the transmitter (e.g., multiple transmit and receive chains, antennas, etc.), with the antenna array having a transmit and receive capacity of up to n×m communication streams per link.

[0110] In an exemplary implementation, the NDP polling trigger 510F may request multiple MU-MIMO capable stations 506F, 507F, 508F, 509F to simultaneously send NDPs (eg, NDP STA 1 、NDP STA 2 …NDP N-1 , NDP N ) is sent to the access point 502F supporting MU-MIMO. The NDP polling trigger 510F may indicate or allocate a target spatial stream for each station 506F, 507F, 508F, 509F to transmit a corresponding NDP (e.g., NDP STA 1 、NDP STA 2 …NDP N-1 , NDP N ), so the access point 502F receives each response simultaneously. The NDP poll trigger 510F can also be used by the stations 506F, 507F, 508F, 509F as a time reference point to coordinate multiple NDPs (e.g., NDP STA 1 、NDP STA 2 …NDP N-1 , NDP N ) on different spatial streams so that the access point 502F supporting MU-MIMO can properly handle NDP (e.g., NDP STA 1 、NDP STA 2 …NDP N-1 , NDP N ) to estimate the forward channel information.

[0111] exist Fig. 5F In the exemplary implementation shown, the first NDP STA 1 The second NDP STA may be sent by station 506F on the first spatial stream. 2 An NDP may be sent by station 507F on the second spatial stream. N-1 The NDP may be sent by station 508F on spatial stream N-1. N Station 509F may transmit on spatial stream N, up to the number of available spatial streams indicated by access point 502F.

[0112] Figure 5G An exemplary sequence of probes requested with different types of sites is shown. Figure 5GIn the exemplary implementation shown, NDP polling 510G may request multiple different sites that are grouped to send dedicated training signals. In one example, different sites (e.g., 506G-50NG) may be grouped based on their capabilities and scheduled to send NDPs at different times.

[0113] For example, the NDP poll 510G may instruct the first group of MU-MIMO capable stations 506G through 50NG to simultaneously send NDPs (eg, NDP STA 1 、NDP STA 2 …NDP N-1 , NDP N ), and further instructs a second group of beamforming capable sites 508G and 509G to sequentially send NDPs 552G, 553G after a response interval. Example implementations may include a combination of different scheduling and training options as discussed herein.

[0114] Figure 6 A flow chart of an exemplary requested sounding beamforming receiver process according to an exemplary implementation is shown. The requested sounding process 600 for the beamforming receiver may include receiving a sounding trigger from a wireless transmitter at 615 and transmitting at least one dedicated training signal in response to the sounding trigger 650. In one example, at 655, the beamforming receiver receives a subsequent packet with a precoding derived from CSI information of the at least one dedicated training signal.

[0115] In an exemplary implementation, the beamformer receiver determines a response time for transmission at 625. The beamformer receiver may process a single sounding trigger to provide multiple dedicated training signals used to determine precoding for subsequent packets sent from the transmitter via a forward channel. The beamformer receiver may determine the response time for transmission without a sounding schedule by, for example, responding immediately, using contention-based transmission, calling a schedule from memory, monitoring a channel for information from other stations, and the like.

[0116] The beamformer receiver may also process the sounding trigger at 620 to set a scheduler for providing additional dedicated training signals and configure the dedicated training signals. In one exemplary implementation, the wireless receiver receives a sounding trigger at 615 that indicates a sounding schedule at 625 and training options for the format of the dedicated training signal. The beamformer receiver stores the sounding schedule and calculates a response time for each of the one or more dedicated training signals based on the sounding schedule.

[0117] In one exemplary implementation, the at least one dedicated training signal from one or more beamformer receivers includes a plurality of dedicated training signals from associated beamformer receivers in response to a sounding trigger. The sounding trigger indicates a sounding schedule for additional dedicated training signals from the associated beamformer receivers, and the plurality of dedicated training signals from the associated beamformer receivers are received at timed intervals based on the sounding schedule.

[0118] At 635, the beamformer receiver may also format a dedicated training signal based on the training options from the sounding trigger. In one example, the beamformer receiver may determine the time to send the dedicated training signal by monitoring the network traffic of the preamble of other dedicated training signals from other receivers in response to the sounding trigger. The beamformer receiver may then derive the packet length of the dedicated training signal based on the other dedicated training signals and determine the response time based on the packet length.

[0119] In another example, where the sounding trigger may indicate a sounding location relative to other receivers, the beamforming receiver calculates one or more response times based on the sounding location and transmits one or more dedicated training signals at the calculated response times.

[0120] Fig. 7A -B shows an example of a requested sounding with timing feedback according to an exemplary implementation. In other exemplary implementations, the beamforming receiver may adapt the requested sounding framework to streamline or support other networking applications other than sounding (e.g., motion tracking, building automation, etc.). In one example, the beamforming receiver may determine the timing feedback based on the measured arrival time of the input packets and the measured departure time of the output packets. The beamforming receiver may then utilize at least one of the dedicated training signals to transmit a timestamp or other timing information. Utilizing the dedicated training signals to include additional timing feedback may effectively synchronize timing, ranging functions, etc. between sites while minimizing the increase in transmission overhead between the beamforming receiver and the beamformer.

[0121] Fig. 7AAn exemplary sequence of requested sounding with timing feedback is shown. In other exemplary implementations, the stations 707, 708, 709 may adapt the requested sounding framework to streamline or support other networking applications besides sounding (e.g., motion tracking, building automation, etc.). In one example, the stations 707, 708, 709 may determine additional feedback parameters 781, 782, 783 to be transmitted to the access point 702E along with the NDPs 751, 752, 753. For example, the stations 751, 752, 753 may determine the timing feedback parameters 781, 782, 783 to be transmitted along with the NDPs 751, 752, 753, and the access point 702 may use these NDPs for other network applications or coordination, such as to effectively synchronize timing between stations, ranging functions, etc.

[0122] The NDP 751, 752, 753 does not include a payload or user data for the requested sounding purpose. However, additional feedback timing feedback parameters 781, 782, 783 may optionally be transmitted with the NDP 751, 752, 753 to streamline or support other networking applications other than sounding (e.g., motion tracking, building automation, etc.). By transmitting the additional feedback parameters 781, 782, 783 with the NDP 751, 752, 753, the access point 702 may initiate multiple functions with a single trigger. For example, the access point 702 may extract or determine timing information from the data (e.g., additional feedback parameters 781, 782, 783) attached to the NDP 751, 752, 753. The beamformer does not require the additional feedback parameters 781, 782, 783 and does not need to use these additional feedback parameters to complete the requested sounding process. However, by operatively coupling additional feedback parameters 781, 782, 783 to the NDPs 751, 752, 753, the number of overhead transmissions between the beamformer and the beamformed receiver may be further reduced.

[0123] Figure 7B FIG. 7 shows an exemplary time sequence of a probe request with timing feedback. In an exemplary implementation, station 708 calculates the time of arrival of incoming packets based on the measured arrival time T 1 and the measured departure time T of the outgoing packet 2The timing feedback 780 may be determined by the station 708. In one example, the timing feedback 780 may be a time, one or more timestamps, or other calculated difference. When responding to the NDP poll 710, during the transmission of the NDP 751, the station 708 may optionally include the timing feedback 780 as additional information 781. By transmitting the timing feedback 780 as additional information 781 during the transmission of the NDP 751, the separate additional transmission of the timing feedback 780 may be eliminated or avoided using the requested sounding framework to effectively provide additional functionality. In addition to the requested sounding from a single transmission from the station 708, the beamforming receiving end may enable the access point 702 to process other applications 760, thereby increasing the availability of the channel.

[0124] Fig. 8A -C shows an example of a sounding requested by another beamformer according to an exemplary implementation. In an exemplary implementation, the sounding requested by a first beamformer (e.g., access point 802) may enable one or more other beamformers (e.g., station 808) to estimate a forward channel 830 to the same station 809 without sending any sounding triggers.

[0125] Fig. 8A An exemplary sequence of requested soundings according to an exemplary implementation is shown. In an example where the access point 802 is a beamformer sounding beamforming receiving end site 809, an access point to station (AP-STA) sounding channel may be described as having both an AP-STA forward channel 820 from the beamformer access point 802 to the beamforming receiving end site 809 and a STA-AP reverse channel 821 from the beamforming receiving end site 809 to the beamformer access point 802. As described above, the beamformer access point 802 may send a single sounding trigger via the AP-STA forward channel 820 received by the beamforming receiving end site 809. The beamforming receiving end site 809 may send multiple dedicated training signals via the STA-AP reverse channel 821 with minimal processing required in response to the single sounding trigger from the AP-STA forward channel 820.

[0126] In an exemplary implementation, multiple beamformers may sound one or more beamformed receivers based on a single requested sounding trigger. Sounding requested by a first beamformer (e.g., access point 802) may enable one or more other beamformers (e.g., station 808) to estimate the STA-STA forward channel 830 to the same station 809 without sending any sounding triggers. For example, the first beamformer access point 802 may send a sounding trigger via the AP-STA forward channel 820, and the beamformed receiver station 809 may respond to the first beamformer access point 802 with an NDP via the STA-AP reverse channel 821, which is overheard by the second beamformed receiver station 808 via the STA-STA reverse channel 831.

[0127] In an example where the site 808 is a beamformer communicating with a beamformed receiver site 809, the sounding channel may be described as having a STA-STA forward channel 830 from the beamformer site 808 to the beamformed receiver site 809 and a STA-STA reverse channel 831 from the beamformed receiver site 809 to the beamformer site 808. For example, as in a mesh network, the second site 808 may be a beamformed receiver of the beamformer access point 802, and the second site 808 may be a beamformer of the beamformed receiver site 809, among other combinations.

[0128] It should be noted that the beamformer and beamforming receiver and channels are not limited to any number or combination of access points and stations. The examples described herein are exemplary and applicable to any combination of communication devices having means for beamformer operation and / or means for beamforming receiver operation.

[0129] In some implementations, the second station 808 may also receive a sounding trigger from the first beamformer (e.g., access point 802) via the second AP forward channel 822. In other implementations, the second station 808 may receive a dedicated training signal from the first station 809 independently of receiving the sounding trigger from the access point 802. The second station 808 may monitor the medium for the dedicated training signal from the beamformed receiving end station 809 (e.g., via the STA-STA reverse channel 831) to estimate the STA-STA forward channel 830 without sending a sounding trigger.

[0130] The beamformer station 808 may perform sounding of the STA-STA forward channel 830 based on overhearing a dedicated training signal sent by the beamformed receiver station 809 to the access point 802 via the AP back channel 821 via the STA-STA back channel 831 .

[0131] Figure 8BAn exemplary sequence of probing multiple beamformers of a beamforming receiving end based on a single requested probing trigger according to an exemplary implementation is shown. At 810, the access point 802 sends a probing trigger to the first station 809 via an AP-STA forward channel 820. At 811, the second station 808 may or may not receive the same probing trigger via another AP-STA forward channel 822.

[0132] At 836, the second station monitors the frequency of the STA-STA reverse channel 831 for the dedicated training signal. Monitoring the frequency of the STA-STA reverse channel 831 can detect transmissions broadcast or sent on other probing channels in the network (e.g., AP-STA forward channel 820, STA-AP reverse channel 821, STA-STA reverse channel 831, another AP-STA forward channel 822, etc.). At 850, the first station 809 sends one or more dedicated training signals to the access point 802 via the AP reverse channel 821 based on the probing trigger. At 870, the second station 808 overhears the one or more dedicated training signals sent by the first station 809 via the STA-STA reverse channel 831. At 875, the second station 808 processes the overheard dedicated training signals to estimate the forward CSI of the STA-STA forward channel 830. At 880 , the second station 808 may transmit subsequent packets to the associated beamformed receiving first station 809 via the STA-STA forward channel 830 based on the estimated forward CSI of the STA-STA forward channel 830 .

[0133] At 860, the access point 802 processes the received dedicated training signal to estimate the forward CSI of the AP-STA forward channel 820. At 866, the access point 802 may transmit subsequent packets to the associated beamformed receiver first station 809 via the AP-STA forward channel 820 based on the estimated forward CSI of the AP-STA forward channel 820. Thus, multiple beamformers may sound one or more beamformed receivers based on a single requested sounding trigger.

[0134] Figure 8C A flowchart is shown of an exemplary sequence for probing an auxiliary beamformer of a beamformer receiver based on a single requested probing trigger from a primary beamformer receiver. The auxiliary beamformer process 840 begins at step 841, where an auxiliary beamformer (e.g., an unsolicited beamformer, a piggyback beamformer, etc.) monitors the communication medium, as described with reference to FIG. Fig. 8A -B discussed.

[0135] At 842, the auxiliary beamformer process detects at least one dedicated training signal from one or more beamformed receivers in response to a sounding trigger sent by another beamformer (eg, a primary beamformer or a requesting beamformer). The auxiliary beamformer does not transmit a sounding trigger.

[0136] At 843, for each overhead dedicated training signal, the auxiliary beamformer process performs steps 844 and 845 to estimate the forward channel state information. At step 844, the auxiliary beamformer process calculates the CSI of the reverse channel by measuring the received dedicated training signal. At 845, based on the characterization of the transmitter's front-end parameters, the auxiliary beamformer process derives the CSI for the forward channel from the CSI of the reverse channel.

[0137] In one exemplary implementation, the auxiliary beamformer process may use the estimated forward CSI to transmit a subsequent packet using the precoded packet with the precoding derived from the estimated CSI at 846. The auxiliary beamformer process repeats at least steps 844 and 845 for each overhead dedicated training signal associated with the beamformed receiver with which the auxiliary beamformer intends to communicate. Thus, the requested sounding frame requires less beamformer processing and less bandwidth than conventional sounding methods.

[0138] Fig. 9 A diagram of an exemplary networked device or system that can be used in conjunction with various exemplary implementations described herein is shown. For example, system 915 can be used as or in conjunction with one or more of the above mechanisms or processes, and can represent a processor, one or more user systems, and / or components of other devices described herein. System 915 can be a networked device, a router, a server, a laptop computer, a mobile device, or any conventional computer, or any other processor-enabled device capable of wired or wireless data communications. Other computer systems and / or architectures can also be used, as will be apparent to those skilled in the art.

[0139] The system 915 preferably includes one or more processors, such as processor 925. Additional processors may be provided, such as auxiliary processors for managing input / output, auxiliary processors for performing floating point math operations, special purpose microprocessors with architectures suitable for fast execution of signal processing algorithms (e.g., digital signal processors), slave processors (e.g., back-end processors) subordinate to the main processing system, additional microprocessors or controllers or coprocessors for dual or multi-processor systems. Such auxiliary processors may be separate processors or may be integrated with the processor 925.

[0140] The processor 925 is preferably connected to a communication bus 920. The communication bus 920 may include a data channel for facilitating the transfer of information between the storage device and other peripheral components of the system 920. The communication bus 920 may also provide a set of signals for communicating with the processor 925, including a data bus, an address bus, and a control bus (not shown). The communication bus 920 may include any standard or non-standard bus architecture, such as an industry standard architecture (ISA), an extended industry standard architecture (EISA), a micro channel architecture (MCA), a peripheral component interconnect (PCI) local bus, or a standard published by the Institute of Electrical and Electronics Engineers (IEEE), including IEEE 802.11, IEEE 1188 general purpose interface bus (GPIB), IEEE 696 / S-30, etc.

[0141] The processor 925 may execute under any operating system (OS) (not shown) in a native or virtual environment. One or more applications including logic units, application programming interface (API) units, etc. may be deployed.

[0142] The system 915 preferably includes a main memory 930, and may also include a secondary memory 935. The main memory 930 provides storage of instructions and data for programs (such as one or more of the functions and / or modules described above) executed on the processor 925. It should be understood that the programs stored in the memory and executed by the processor 925 can be written and / or compiled according to any suitable language, including but not limited to C / C++, Java, JavaScript, Pearl, Visual Basic, .NET, etc. The main memory 930 is typically a semiconductor-based memory, such as a dynamic random access memory (DRAM) and / or a static random access memory (SRAM). Other semiconductor-based memory types include, for example, synchronous dynamic random access memory (SDRAM), Rambus dynamic random access memory (RDRAM), ferroelectric random access memory (FRAM), etc., including read-only memory (ROM).

[0143] The secondary storage 935 may optionally include an internal memory 940 and / or a removable medium 945, such as a digital versatile disk (DVD) drive, other optical disk drives, flash memory drives, etc. The removable medium 945 is read from and / or written to in a well-known manner. The removable storage medium 945 may be, for example, a floppy disk, a tape, a CD, a DVD, an SD card, etc. The removable storage medium 945 is a non-transitory computer-readable medium having computer executable code (i.e., software) and / or data stored thereon.

[0144] Other examples of auxiliary memory 935 may include semiconductor-based memory such as programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable read-only memory (EEPROM), or flash memory (block-oriented memory similar to EEPROM). Also included are any other removable storage media 945 and communication interfaces 955 that allow software and data to be transferred from external media 960 to system 915.

[0145] The system 915 may include a communication interface 955. The communication interface 955 allows software and data to be transferred between the system 915 and an external device (e.g., a printer), a network, or an information source. For example, computer software or executable code may be transferred from a network server to the system 915 via the communication interface 955. Examples of the communication interface 955 include a built-in network adapter, a network interface card (NIC), a Personal Computer Memory Card International Association (PCMCIA) network card, a cardbus network adapter, a wireless network adapter, a universal serial bus (USB) network adapter, a modem, a network interface card (NIC), a wireless data card, a communications port, an infrared interface, an IEEE 1394 FireWire, or any other device capable of interacting the system 915 with a network or another computing device.

[0146] The communication interface 955 preferably implements industry-promulgated protocol standards, such as Ethernet IEEE 802 standards, Fiber Channel, Digital Subscriber Line (DSL), Asynchronous Digital Subscriber Line (ADSL), Frame Relay, Asynchronous Transfer Mode (ATM), Integrated Services Digital Network (ISDN), Personal Communications Service (PCS), Transmission Control Protocol / Internet Protocol (TCP / IP), Serial Internet Protocol / Point-to-Point Protocol (SLIP / PPP), etc., but customized or non-standard interface protocols may also be implemented.

[0147] Software and data transmitted via the communication interface 955 are typically in the form of electrical communication signals 970. These signals 970 are preferably provided to the communication interface 955 via a communication channel 965. In one exemplary implementation, the communication channel 965 may be a wired or wireless network, or any other communication link. By way of example, the communication channel 965 carries the signals 970 and may be implemented using a variety of wired or wireless communication means including wire or cable, fiber optics, a conventional telephone line, a cellular telephone link, a wireless data communication link, a radio frequency ("RF") link, or an infrared link.

[0148] Computer executable code (i.e., computer programs or software) is stored in the main memory 930 and / or the secondary memory 935. The computer programs may also be received via the communication interface 955 and stored in the main memory 930 and / or the secondary memory 935. Such computer programs, when executed, enable the system 915 to perform the various functions of the present invention as previously described.

[0149] For example, the communication interface 955 coupled to the processor 925 may be configured to operate the wireless transceiver, including transmitting a sounding trigger to one or more receivers, and receiving at least one dedicated training signal from the one or more receivers via a reverse channel in response to the sounding trigger. For each received dedicated training signal, the dedicated training signal may estimate a forward CSI based on a dedicated training signal from an associated receiver; and wherein a subsequent packet is precoded with a precoding derived from the forward CSI for transmission to the associated receiver via a forward channel.

[0150] According to an exemplary implementation, the processor 925 may be configured to transmit additional sounding triggers to the target additional receivers, wherein in response to each additional sounding trigger, a separate additional dedicated training signal is received from each of the additional receivers, and wherein for each separate additional dedicated training signal received, the processor further estimates a CSI for the additional receiver associated with the separate additional dedicated training signal; and transmits additional guided packets to the additional receivers based on the CSI. The sounding trigger is not preceded by an announcement frame, and the receiver does not process the sounding trigger to generate detailed sounding feedback (e.g., SVD based on compressed beamforming feedback).

[0151] In another example, the communication interface 955 coupled to the processor 925 may be configured to operate a wireless receiver, including receiving a sounding trigger from a wireless transmitter, transmitting at least one dedicated training signal in response to the sounding trigger; and receiving subsequent packets with precoding derived from CSI information of the at least one dedicated training signal.

[0152] Transmitting at least one dedicated training signal in response to a sounding trigger may include transmitting multiple dedicated training signals without receiving another sounding trigger. In one example, the sounding trigger indicates a sounding schedule and training options for a dedicated training signal format, and the processor 925 is configured to store the sounding schedule, calculate the response time of each of the one or more dedicated training signals based on the sounding schedule, and format the dedicated training signal based on the training options. The sounding schedule instruction may indicate a sounding time for transmitting a dedicated training signal coordinated with a group of receivers (e.g., sequentially, continuously, simultaneously, burst-wise, etc.). In other exemplary implementations, the processor 925 is configured to determine the response time for transmitting additional dedicated training signals without receiving additional prompts from the beamformer. In this example, the wireless transceiver may transmit additional sounding triggers to target additional beamforming receiving ends. For example, the additional sounding trigger initiates a series of separate additional dedicated training signals from each of the additional beamforming receiving ends. In addition, in response to each additional sounding trigger, the additional sounding trigger initiates a series of separate additional dedicated training signals from each of the additional beamforming receiving ends.

[0153] In one example, operating a wireless transceiver for estimating forward CSI includes measuring channel information from a dedicated training signal received via a reverse channel, calculating CSI of the reverse channel from the measured channel information, and deriving forward CSI of the forward channel from the CSI of the reverse channel based on characteristics of a radio frequency front end of the transceiver, wherein subsequent packets are transmitted to an associated beamformed receiving end via the forward channel.

[0154] In some examples, the wireless transceiver device includes multiple sets and / or subsets of antennas, multiple components coupled to each other to form a transmit chain and a receive chain, and a requester module circuit that transmits a sounding trigger via a forward channel to request multiple dedicated training signals from one or more beamforming receivers. For example, the dedicated training signals can be processed to improve subsequent transmission of data to the associated beamforming receivers (e.g., to estimate forward channel state information (CSI) for transmitting subsequent packets to the associated beamforming receivers).

[0155] A wireless transceiver having a requester module circuit generates a sounding trigger indicating a control schedule (e.g., training options for a format of at least one dedicated training signal in a plurality of dedicated training signals based on communication parameters of a target beamformer receiving end). For example, the communication parameters of the target beamformer receiving end include a combination of one or more of target beamforming capabilities, traffic type, positioning parameters, etc.

[0156] In another example, a wireless transceiver with a requester module circuit may include a detection module circuit coupled to multiple components. In other examples, a wireless device without a transceiver requester module circuit may include a detection module circuit coupled to multiple components. The detection module circuit may process a dedicated training signal, for example, when each dedicated training signal is received, the detection module circuit will perform the following operations: measure the channel information of the dedicated training signal received via the reverse channel, calculate the CSI of the reverse channel from the measured channel information, and derive the forward CSI of the forward channel from the CSI of the reverse channel according to the characteristics of the RF front end of the transceiver.

[0157] In other examples, the wireless transceiver device includes multiple sets and / or subsets of antennas, multiple components coupled to each other to form a transmit chain and a receive chain, and a detection module circuit coupled to the multiple sets and / or subsets of antennas. The wireless transceiver in this example does not require a requester module circuit and can use a requester module circuit originally provided by another wireless transceiver (e.g., a wireless transceiver with a requester module circuit). The detection module circuit can detect at least one dedicated training signal from one or more beamformed receiving ends, wherein the at least one dedicated training signal is based on a detection trigger from another beamformer.

[0158] 18. The wireless transceiver device of claim 15, wherein the sounding trigger indicates a sounding schedule with time intervals configured based on communication parameters of the target beamforming receiver, the communication parameters of the target beamforming receiver comprising at least one of the following: target beamforming receiver capabilities, service type, and positioning parameters.

[0159] Transmitting at least one dedicated training signal may be performed by the communication interface 955 at timed intervals based on a sounding schedule indicated by the sounding trigger. In another example, transmitting at least one dedicated training signal may be based on monitoring preambles of other dedicated training signals from other receivers in response to the sounding trigger; deriving a packet length of the dedicated training signal based on the other dedicated training signals; and determining a response time based on the packet length.

[0160] In another embodiment, any of the examples described may include receiving at least one dedicated training signal with timing information. Such timing information may indicate packet transmission and reception timestamps. The timing information may be used for applications other than the detection process, such as motion tracking, location mapping, etc.

[0161] In this specification, the term "computer-readable medium" is used to refer to any non-transitory computer-readable storage medium for providing computer executable code (e.g., software and computer programs) to the system 915. Examples of these media include main memory 930, auxiliary memory 935 (including internal memory 940, removable media 945, and external storage media 945), and any peripheral devices (including network information servers or other network devices) communicatively coupled to the communication interface 955. These non-transitory computer-readable media are means for providing executable code, programming instructions, and software to the system 915.

[0162] In an exemplary implementation using software implementation, the software may be stored on a computer readable medium and loaded into the system 915 through the removable media 945, the I / O interface 950, or the communication interface 955. In such an exemplary implementation, the software is loaded into the system 915 in the form of an electrical communication signal 970.

[0163] In an exemplary implementation, the I / O interface 950 provides an interface between one or more components of the system 915 and one or more input and / or output devices. Exemplary input devices include, but are not limited to, a keyboard, a touch screen or other touch-sensitive device, a biometric sensing device, a computer mouse, a trackball, a pen-based pointing device, and the like.

[0164] System 915 also includes optional wireless communication components that facilitate wireless communication over voice and over data networks. The wireless communication components include antenna system 975, radio system 980, and baseband system 985. In system 915, radio frequency (RF) signals are transmitted and received over the air by antenna system 975 under the management of radio system 980.

[0165] In one exemplary implementation, the antenna system 975 may include one or more antennas and one or more multiplexers (not shown) that perform switching functions to provide transmit and receive signal paths for the antenna system 975. In the receive path, the received RF signal may be coupled from the multiplexer to a low noise amplifier (not shown) that amplifies the received RF signal and sends the amplified signal to the radio system 980.

[0166] In an alternative exemplary implementation, the radio system 980 may include one or more radio components configured to communicate over various frequencies. In one exemplary implementation, the radio system 980 may combine a demodulator (not shown) and a modulator (not shown) in one integrated circuit (IC). The demodulator and modulator may also be separate components. In the incoming path, the demodulator strips off the RF carrier signal leaving a baseband receive audio signal that is sent from the radio system 980 to the baseband system 985.

[0167] If the received signal contains audio information, the baseband system 985 decodes the signal and converts it to an analog signal. The signal is then amplified and sent to a speaker. The baseband system 985 also receives analog audio signals from a microphone. These analog audio signals are converted into digital signals and encoded by the baseband system 985. The baseband system 985 also encodes the digital signal for transmission and generates a baseband transmission audio signal routed to the modulator portion of the radio system 980. The modulator mixes the baseband transmission audio signal with an RF carrier signal that generates an RF transmission signal, which is routed to the antenna system and may pass through a power amplifier (not shown). The power amplifier amplifies the RF transmission signal and routes it to the antenna system 975, where the signal is switched to the antenna port for transmission.

[0168] The baseband system 985 is also communicatively coupled to the processor 925. The central processing unit 925 has access to data storage areas 930 and 935. The central processing unit 925 is preferably configured to execute instructions (i.e., computer programs or software) that may be stored in the memory 930 or the auxiliary memory 935. Computer programs may also be received from the baseband processor 985 and stored in the data storage area 930 or the auxiliary memory 935, or executed upon receipt. Such computer programs, when executed, enable the system 915 to perform various functions of the present invention as previously described. For example, the data storage area 930 may include various software modules (not shown).

[0169] Some portions of the detailed description are presented in terms of algorithms and symbolic representations of operations within a computer. These algorithmic descriptions and symbolic representations are a means for those skilled in the art of data processing to convey the essence of their innovations to others skilled in the art. An algorithm is a defined sequence of operations that produces a desired end state or result. In an exemplary implementation, the operations performed require a tangible number of physical manipulations to achieve a tangible result.

[0170] Unless otherwise specifically stated, it will be apparent from the discussion that it should be understood that throughout the description, discussions utilizing terms such as detecting, determining, analyzing, identifying, scanning, etc., may include actions and processes of a computer system or other information processing device that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system's memories or registers or other information storage, transmission, or display devices.

[0171] Example implementations may also be directed to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may include one or more general-purpose computers selectively activated or reconfigured by one or more computer programs.

[0172] An exemplary device may include a wireless access point (WAP) or site, and incorporates a very large scale integration (VLSI) processor and program code to support. An exemplary transceiver is coupled to one of a cable, optical fiber or digital subscriber backbone connection to the Internet via an integrated modem to support wireless communications on a wireless local area network (WLAN), such as IEEE 802.11 compatible communications. The Wi-Fi stage includes a baseband stage, as well as an analog front end (AFE) and a radio frequency (RF) stage. In the baseband portion, wireless communications transmitted to or received from each user / client / site are processed. The AFE and RF portions handle the up-conversion on each transmit path of the wireless transmission initiated in the baseband. The RF portion also handles the down-conversion of signals received on the receive path, and passes them to the baseband for further processing.

[0173] The WAP and / or station may support multiple protocols and multi-language protocols capable of communicating with multiple protocols (e.g., IoT protocols, including Bluetooth Low Energy, Zigbee, Thread, etc.) and communicatively coupled to one or more resources to access analytics or machine learning capabilities. In some implementations, the WAP and / or station is battery powered and mobile, or integrated into a larger mobile device such as a car or airplane.

[0174] An exemplary device may be a multiple-input multiple-output (MIMO) device that supports up to N×N discrete communication streams through N antennas. In an example, the MIMO device signal processing unit may be implemented as N×N. In various examples, the value of N may be 4, 6, 8, 12, 16, etc. Extended MIMO operation enables the use of up to 2N antennas to communicate with another similarly equipped wireless system. It should be noted that an extended MIMO system can communicate with other wireless systems even if the systems do not have the same number of antennas, but some antennas of one of the stations may not be utilized, thereby reducing optimal performance.

[0175] In some implementations, without departing from the present disclosure, the beamforming antenna configuration detection discussed herein may be equally advantageously applied to WAPs or stations having any number of transmit chains, receive chains, or MIMO antennas, including but not limited to: 1×2, 1×n, 2×3, 2×4, 2×n, 3×4, 3×n, 4×5, 4×8, 4×n, 8×9, 8×16, 8×n, etc. The components and processes disclosed herein may be implemented in a combination of software, circuitry, hardware, and firmware, integrated with existing transmit and receive path components of a WAP without departing from the scope of the present disclosure.

[0176] An exemplary transmission path / transmission chain includes the following discrete and shared components. The Wi-Fi Medium Access Control (WMAC) component includes: a hardware queue for each downlink and uplink communication flow; encryption and decryption circuitry for encrypting and decrypting downlink and uplink communication flows; medium access circuitry for performing clear channel assessment (CCA) and making exponential random backoff and retransmission decisions; and packet processor circuitry for packet processing of transmitted and received communication flows. The WMAC component has access to a node table that lists each node / station on the WLAN, the station's capabilities, the corresponding encryption keys, and the priority associated with its communication traffic.

[0177] Each probe or data packet for wireless transmission to one or more stations on the transmission path component is framed in the framer. Next, each stream is encoded and scrambled in the encoder and scrambler, and then demultiplexed into separate streams in the demultiplexer. The following streams are interleaved and mapped in the corresponding one of the interleaving mappers. Next, all transmissions are spatially mapped using the spatial mapping matrix (SMM) in the spatial mapper. The spatially mapped stream from the spatial mapper is input to the inverse discrete Fourier transform (IDFT) component for conversion from the frequency domain to the time domain and subsequent transmission in the AFT and RF stages.

[0178] The IDFTs are coupled to corresponding ones of the transmit paths / chains in the AFT RF stage for wireless transmission on an associated one of the MIMO antennas. Specifically, each IDFT is coupled to an associated one of the digital-to-analog converters (DACs) 550 for converting the digital transmission to analog, a filter, an upconverter, a common voltage controlled oscillator (VCO) for upconverting the transmission to the appropriate center frequency of the selected channel, and a power amplifier for setting the transmission power level of the transmission on the MIMO antenna array.

[0179] The receive path / receive chain includes the following discrete and shared components. In the AFE-RF stage, RF processing is performed on the communications received on the MIMO antenna array of the WAP, including downconversion. There are six receive paths, each of which includes the following discrete and shared components: a low noise amplifier (LNA) for amplifying the received signal under the control of an analog gain control (AGC) (not shown), which is used to set the amount by which the received signal is amplified; a downconverter coupled to the VCO for downconverting the received signal, a filter for bandpass filtering the received signal, and an analog-to-digital converter (ADC) for digitizing the downconverted signal. In an exemplary implementation, an optional sampler 568 at the output of the ADC allows the received Wi-Fi signal in the time domain to be sampled for subsequent Wi-Fi spatial diagnostics performed by a processor and non-volatile memory. The digital output from each ADC is passed to a corresponding one of the discrete Fourier transform (DFT) components in the baseband portion of the Wi-Fi stage for conversion from the time domain to the frequency domain.

[0180] The receive processing in the baseband stage includes the following shared and discrete components, including: an equalizer for suppressing channel loss, the equalizer being coupled to the output of the DFT. In an exemplary implementation, a Wi-Fi signal received in the frequency domain with or without equalization from the output of the DFT is provided to a processor and a non-volatile memory. The received Wi-Fi stream at the output of the equalizer undergoes demapping and deinterleaving in a corresponding number of demappers and deinterleavers. Next, the received one or more streams are multiplexed in a multiplexer and decoded and descrambled in a decoder and descrambler component, and then deframed in a deframer. The received communication is then passed to the WMAC component, where the received communication is decrypted with a decryption circuit and placed in an appropriate upstream hardware queue for upload to the Internet.

[0181] Non-transitory computer readable storage media may involve tangible media, such as, but not limited to, optical disks, magnetic disks, read-only memories, random access memories, solid-state devices and drives, or any other type of tangible or non-transitory media suitable for storing electronic information. Computer readable signal media may include media, such as carrier waves. The algorithms and displays presented herein are not inherently related to any particular computer or other device. A computer program may involve a pure software implementation involving instructions for performing the operations of the desired implementation.

[0182] The computing device may be communicatively coupled to an input / user interface and an output device / interface. One or both of the input / user interface and the output device / interface may be a wired or wireless interface and may be detachable. The input / user interface may include any device, component, sensor, or interface, physical or virtual, that can be used to provide input (e.g., buttons, touch screen interfaces, keyboards, pointing / cursor controls, microphones, cameras, embossing, motion sensors, optical readers, etc.).

[0183] The term "communicatively connected" is intended to include any type of wired or wireless connection in which data can be transferred. The term "communicatively connected" is intended to include, but is not limited to, connections between devices and / or programs within a single computer, or connections between devices and / or separate computers over a network. The term "network" is intended to include, but is not limited to, packet switching networks such as a local area network (LAN), a wide area network (WAN), TCP / IP (the Internet), and may use various transmission means such as, but not limited to, TCP / IP. Internet Protocol version 6 over a low power wireless area network (6LowPAN), power line communication (PLC), Ethernet (e.g., 10 megabyte (Mb), 100 megabyte (Mb), and / or 1 gigabyte (Gb) Ethernet), or other communication protocols.

[0184] In addition, some exemplary implementations of the present application may be performed only in hardware, while other functions may be performed only in software. In addition, the various functions described may be performed in a single unit, or may be distributed across multiple components in any number of ways. When performed by software, the method may be performed by a processor such as a general-purpose computer based on instructions stored on a computer-readable medium. If necessary, the instructions may be stored on the medium in a compressed and / or encrypted format.

[0185] The exemplary embodiments may have various differences and advantages over the related art. In addition, other embodiments of the present application will be apparent to those skilled in the art in view of the practice of the specification and teachings of the present application. The various aspects and / or components of the exemplary embodiments may be used alone or in any combination. The specification and exemplary embodiments are intended to be considered as examples only, with the true scope and substance of the present application being indicated by the following claims.

Claims

1. A method for operating a wireless transceiver: transmitting the detection trigger to one or more beamforming receivers via a forward channel; In response to the sounding trigger, at least one dedicated training signal is received from the one or more beamformer receiving ends via a reverse channel.

2. The method for operating the wireless transceiver according to claim 1, wherein for each of the received dedicated training signals: estimating forward channel state information (CSI) derived based on the dedicated training signal from an associated beamformee; and wherein subsequent packets are precoded with a precoding derived from the forward CSI for transmission to the associated beamformee via the forward channel.

3. The method for operating the wireless transceiver of claim 2, wherein estimating the forward CSI comprises: measuring channel information from the dedicated training signal received via the reverse channel; Calculating the CSI of the reverse channel according to the measured channel information; as well as The forward CSI of the forward channel is derived from the CSI of the reverse channel according to characteristics of a radio frequency front end of the transceiver, wherein the subsequent packet is transmitted to the associated beamforming receiving end via the forward channel.

4. The method for operating the wireless transceiver according to any one of the preceding claims, wherein the receiving of at least one dedicated training signal from the one or more beamforming receiving ends comprises: In response to the detection trigger, a plurality of dedicated training signals are received from the associated beamforming receiving end.

5. The method for operating the wireless transceiver according to claim 4, wherein the sounding trigger indicates a sounding schedule of additional dedicated training signals from the associated beamformer receiving end, and The multiple dedicated training signals are received from the associated beamforming receiving end at regular intervals based on the sounding schedule.

6. The method for operating the wireless transceiver according to claim 1 or 4, wherein receiving at least one dedicated training signal from the one or more beamforming receiving ends comprises: In response to the detection trigger, a plurality of dedicated training signals are received from different beamforming receiving ends.

7. The method for operating the wireless transceiver according to claim 1, Wherein receiving at least one dedicated training signal can include timing information indicating packet transmission and reception times or timestamps.

8. A method for operating the wireless transceiver according to any one of the preceding claims, wherein the sounding trigger indicates a separate spatial stream for each of the different beamforming receiving ends to transmit the dedicated training signal; and The multiple dedicated training signals are received simultaneously from the different beamforming receiving ends on separate spatial streams.

9. A method for operating the wireless transceiver according to any one of the preceding claims, The probing trigger indicates a probing schedule, and the probing schedule includes at least one of the following: a probing interval, a probing position, and a schedule expiration.

10. The method for operating the wireless transceiver according to claim 4 or 9, wherein the sounding schedule indicates sounding times for a group of beamforming receiving ends to send dedicated training signals via the reverse channel.

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