Trigger frame for ranging

A first communication device generates and transmits a first trigger frame. One or more trigger type information fields of the first trigger frame are set to a first one or more respective values that indicates the first trigger frame is for: i) a multi-user (MU) ranging measurement procedure, and ii) causing multiple second communication devices to simultaneously transmit first null data packets (NDPs) as part of a first MU transmission associated with the MU ranging measurement procedure. The first communication device generates and transmits a second trigger frame. One or more trigger type information fields of the second trigger frame are set to a second one or more respective values that indicates the second trigger frame is for i) an MU ranging measurement procedure, and ii) causing the multiple second communication devices to simultaneously transmit feedback packets to the first communication device as part of a second MU transmission associated with the MU ranging measurement procedure.

FIELD OF TECHNOLOGY

The present disclosure relates generally to wireless communication systems, and more particularly to communication exchanges between wireless communication devices for ranging measurements among the wireless communication devices.

BACKGROUND

Wireless local area networks (WLANs) have evolved rapidly over the past decade, and development of WLAN standards such as the Institute for Electrical and Electronics Engineers (IEEE) 802.11 Standard family has improved single-user peak data throughput. For example, the IEEE 802.11b Standard specifies a single-user peak throughput of 11 megabits per second (Mbps), the IEEE 802.11a and 802.11g Standards specify a single-user peak throughput of 54 Mbps, the IEEE 802.11n Standard specifies a single-user peak throughput of 510 Mbps, and the IEEE 802.11ac Standard specifies a single-user peak throughput in the gigabits per second (Gbps) range. Future standards promise to provide even greater throughput, such as throughputs in the tens of Gbps range.

Some mobile communication devices include a WLAN network interface and satellite positioning technology, such as global positioning system (GPS) technology. GPS technology in mobile communication devices is useful for navigating to a desired location, for example. However, GPS technology does not typically provide accurate location information when a GPS receiver is not in direct sight of a GPS satellite, and thus GPS technology is often not useful for providing location information while a mobile communication device is within a building such as an airport, a shopping mall, etc., within a tunnel, etc.

Techniques for determining a position of a communication device using WLAN technology are now under development. For example, a distance between a first communication and a second communication device is determined by measuring a time of flight of WLAN transmissions between the first communication device and the second communication device, and calculating the distance based on the time of flight. Similarly, distances between the first communication device and multiple third communication devices are determined. Then, the determined distances are used to estimate a location of the first communication device by employing, for example, a triangulation technique. For a first communication device having multiple antennas, an angle of departure (AoD) of a WLAN transmission can be determined. Similarly, for a second communication device having multiple antennas, an angle of arrival (AoA) of the WLAN transmission from the first communication device can be determined. The AoD and the AoA, along with the determined distances, can be also be used for estimating the location of the first communication device.

SUMMARY

In an embodiment, a method for performing ranging measurements includes: generating, at a first communication device, a first trigger frame according to a trigger frame format that includes one or more trigger type information fields for indicating a type of multi-user (MU) frame exchange to which a trigger frame instance corresponds. Generating the first trigger frame includes: setting the one or more trigger type information fields of the first trigger frame to a first one or more respective values that indicates the first trigger frame is for: i) an MU ranging measurement procedure, and ii) causing multiple second communication devices from among a plurality of second communication devices to simultaneously transmit first null data packets (NDPs) to the first communication device as part of a first MU transmission associated with the MU ranging measurement procedure. The method also includes: transmitting, by the first communication device, the first trigger frame to cause the multiple second communication devices to transmit the first NDPs as part of the first MU transmission; receiving, at the first communication device, the first MU transmission having multiple first NDPs transmitted simultaneously by at least some of the multiple second communication devices; transmitting, by the first communication device, a second NDP to the multiple second communication devices as part of the MU ranging measurement procedure; and generating, at the first communication device, a second trigger frame according to the trigger frame format. Generating the second trigger frame includes: setting the one or more trigger type information fields of the second trigger frame to a second one or more respective values that indicates the second trigger frame is for i) an MU ranging measurement procedure, and ii) causing the multiple second communication devices to simultaneously transmit feedback packets to the first communication device as part of a second MU transmission associated with the MU ranging measurement procedure. The method further includes: transmitting, by the first communication device, the second trigger frame to cause the multiple second communication devices to transmit the feedback packets as part of the second MU transmission; receiving, at the first communication device, the second MU transmission having multiple feedback packets transmitted simultaneously by at least some of the multiple second communication devices, the multiple feedback packets including ranging measurement feedback information; and calculating, at the first communication device, one or more respective distances between the first communication device and at least one of the multiple second communication devices using the measurement feedback information received in the second MU transmission.

In another embodiment, an apparatus comprises: a network interface device associated with a first communication device. The network interface device includes one or more integrated circuits (ICs), and is configured to: generate a first trigger frame according to a trigger frame format that includes one or more trigger type information fields for indicating a type of multi-user (MU) frame exchange to which a trigger frame instance corresponds. Generating the first trigger frame includes: setting the one or more trigger type information fields of the first trigger frame to a first one or more respective values that indicates the first trigger frame is for i) an MU ranging measurement procedure, and ii) causing multiple second communication devices from among a plurality of second communication devices to simultaneously transmit first null data packets (NDPs) to the first communication device as part of a first MU transmission associated with the MU ranging measurement procedure. The network interface device is also configured to: transmit the first trigger frame to cause the multiple second communication devices to transmit the first NDPs as part of the first MU transmission; receive the first MU transmission having multiple first NDPs transmitted simultaneously by at least some of the multiple second communication devices; transmit a second NDP to the multiple second communication devices as part of the MU ranging measurement procedure; and generate a second trigger frame according to the trigger frame format. Generating the second trigger frame includes: setting the one or more trigger type information fields of the second trigger frame to a second one or more respective values that indicates the second trigger frame is for i) an MU ranging measurement procedure, and ii) causing the multiple second communication devices to simultaneously transmit feedback packets to the first communication device as part of a second MU transmission associated with the MU ranging measurement procedure. The network interface device is further configured to: transmit the second trigger frame to cause the multiple second communication devices to transmit the feedback packets as part of the second MU transmission; receive the second MU transmission having multiple feedback packets transmitted simultaneously by at least some of the multiple second communication devices, the multiple feedback packets including ranging measurement feedback information; and calculate one or more respective distances between the first communication device and at least one of the multiple second communication devices using the measurement feedback information received in the second MU transmission.

In yet another embodiment, a method for performing ranging measurements includes: receiving, at a first communication device and from a second communication device, a first trigger frame according to a trigger frame format that includes one or more trigger type information fields for indicating a type of multi-user (MU) frame exchange to which a trigger frame instance corresponds. The first trigger frame includes: the one or more trigger type information fields of the first trigger frame set to a first one or more respective values that indicates the first trigger frame is for i) an MU ranging measurement procedure, and ii) causing the first communication device and one or more third communication devices to simultaneously transmit respective first null data packets (NDPs) to the second communication device as part of a first MU transmission associated with the MU ranging measurement procedure. The method also includes: transmitting, by the first communication device to the second communication device, a first NDP as part of the first MU transmission in response to the first trigger frame; receiving, at the first communication device and from the second communication device, a second NDP as part of the MU ranging measurement procedure; and receiving, at the first communication device and from the second communication device, a second trigger frame according to the trigger frame format. The second trigger frame includes: the one or more trigger type information fields of the second trigger frame set to a second one or more respective values that indicates the second trigger frame is for i) an MU ranging measurement procedure, and ii) causing the first communication device and the one or more third communication devices to simultaneously transmit respective feedback packets to the second communication device as part of a second MU transmission associated with the MU ranging measurement procedure. The method further includes: transmitting, by the first communication device to the second communication device, a feedback packet as part of the second MU transmission in response to the second trigger frame, the feedback packet including ranging measurement feedback information, wherein the ranging measurement feedback information is useable at the second communication device to calculate a distance between the first communication device and the second communication device.

In still another embodiment, an apparatus comprises: a network interface device associated with a first communication device. The network interface device includes one or more integrated circuits (ICs), and is configured to: receive, from a second communication device, a first trigger frame according to a trigger frame format that includes one or more trigger type information fields for indicating a type of multi-user (MU) frame exchange to which a trigger frame instance corresponds. The first trigger frame includes: the one or more trigger type information fields of the first trigger frame set to a first one or more respective values that indicates the first trigger frame is for i) an MU ranging measurement procedure, and ii) causing the first communication device and one or more third communication devices to simultaneously transmit respective first null data packets (NDPs) to the second communication device as part of a first MU transmission associated with the MU ranging measurement procedure. The network interface device is also configured to: transmit, to the second communication device, a first NDP as part of the first MU transmission in response to the first trigger frame; receive, from the second communication device, a second NDP as part of the MU ranging measurement procedure; and receive, from the second communication device, a second trigger frame according to the trigger frame format. The second trigger frame includes: the one or more trigger type information fields of the second trigger frame set to a second one or more respective values that indicates the second trigger frame is for i) an MU ranging measurement procedure, and ii) causing the first communication device and the one or more third communication devices to simultaneously transmit respective feedback packets to the second communication device as part of a second MU transmission associated with the MU ranging measurement procedure. The network interface device is further configured to: transmit, to the second communication device, a feedback packet as part of the second MU transmission in response to the second trigger frame, the feedback packet including ranging measurement feedback information, wherein the ranging measurement feedback information is useable at the second communication device to calculate a distance between the first communication device and the second communication device.

DETAILED DESCRIPTION

Ranging measurement procedures and techniques described below are discussed in the context of wireless local area networks (WLANs) that utilize protocols the same as or similar to protocols defined by the 802.11 Standard from the Institute of Electrical and Electronics Engineers (IEEE) merely for explanatory purposes. In other embodiments, however, ranging measurement procedures and techniques are utilized in other types of wireless communication systems such as personal area networks (PANs), mobile communication networks such as cellular networks, metropolitan area networks (MANs), etc.

FIG. 1is a block diagram of an example WLAN110, according to an embodiment. The WLAN110includes an access point (AP)114that comprises a host processor118coupled to a network interface device122. The network interface122includes a medium access control (MAC) processor126and a physical layer (PHY) processor130. The PHY processor130includes a plurality of transceivers134, and the transceivers134are coupled to a plurality of antennas138. Although three transceivers134and three antennas138are illustrated inFIG. 1, the AP114includes other suitable numbers (e.g., 1, 2, 4, 5, etc.) of transceivers134and antennas138in other embodiments. In some embodiments, the AP114includes a higher number of antennas138than transceivers134, and antenna switching techniques are utilized.

The network interface122is implemented using one or more integrate circuits (ICs) configured to operate as discussed below. For example, the MAC processor126may be implemented, at least partially, on a first IC, and the PHY processor130may be implemented, at least partially, on a second IC. As another example, at least a portion of the MAC processor126and at least a portion of the PHY processor130may be implemented on a single IC. For instance, the network interface122may be implemented using a system on a chip (SoC), where the SoC includes at least a portion of the MAC processor126and at least a portion of the PHY processor130.

In an embodiment, the host processor118includes a processor configured to execute machine readable instructions stored in a memory device (not shown) such as a random access memory (RAM), a read-only memory (ROM), a flash memory, etc. In an embodiment, the host processor118may be implemented, at least partially, on a first IC, and the network device122may be implemented, at least partially, on a second IC. As another example, the host processor118and at least a portion of the network interface122may be implemented on a single IC.

In various embodiments, the MAC processor126and/or the PHY processor130of the AP114are configured to generate data units, and process received data units, that conform to a WLAN communication protocol such as a communication protocol conforming to the IEEE 802.11 Standard or another suitable wireless communication protocol. For example, the MAC processor126may be configured to implement MAC layer functions, including MAC layer functions of the WLAN communication protocol, and the PHY processor130may be configured to implement PHY functions, including PHY functions of the WLAN communication protocol. For instance, the MAC processor126may be configured to generate MAC layer data units such as MAC service data units (MSDUs), MAC protocol data units (MPDUs), etc., and provide the MAC layer data units to the PHY processor130. The PHY processor130may be configured to receive MAC layer data units from the MAC processor126and encapsulate the MAC layer data units to generate PHY data units such as PHY protocol data units (PPDUs) for transmission via the antennas138. Similarly, the PHY processor130may be configured to receive PHY data units that were received via the antennas138, and extract MAC layer data units encapsulated within the PHY data units. The PHY processor130may provide the extracted MAC layer data units to the MAC processor126, which processes the MAC layer data units.

The PHY processor130is configured to downconvert one or more radio frequency (RF) signals received via the one or more antennas138to one or more baseband analog signals, and convert the analog baseband signal(s) to one or more digital baseband signals, according to an embodiment. The PHY processor130is further configured to process the one or more digital baseband signals to demodulate the one or more digital baseband signals and to generate a PPDU. The PHY processor130includes amplifiers (e.g., a low noise amplifier (LNA), a power amplifier, etc.), a radio frequency (RF) downconverter, an RF upconverter, a plurality of filters, one or more analog-to-digital converters (ADCs), one or more digital-to-analog converters (DACs), one or more discrete Fourier transform (DFT) calculators (e.g., a fast Fourier transform (FFT) calculator), one or more inverse discrete Fourier transform (IDFT) calculators (e.g., an inverse fast Fourier transform (IFFT) calculator), one or more modulators, one or more demodulators, etc.

The PHY processor130is configured to generate one or more RF signals that are provided to the one or more antennas138. The PHY processor130is also configured to receive one or more RF signals from the one or more antennas138.

The MAC processor126is configured to control the PHY processor130to generate one or more RF signals by, for example, providing one or more MAC layer data units (e.g., MPDUs) to the PHY processor130, and optionally providing one or more control signals to the PHY processor130, according to some embodiments. In an embodiment, the MAC processor126includes a processor configured to execute machine readable instructions stored in a memory device (not shown) such as a RAM, a read ROM, a flash memory, etc. In an embodiment, the MAC processor126includes a hardware state machine.

The WLAN110includes a plurality of client stations154. Although three client stations154are illustrated inFIG. 1, the WLAN110includes other suitable numbers (e.g., 1, 2, 4, 5, 6, etc.) of client stations154in various embodiments. The client station154-1includes a host processor158coupled to a network interface device162. The network interface162includes a MAC processor166and a PHY processor170. The PHY processor170includes a plurality of transceivers174, and the transceivers174are coupled to a plurality of antennas178. Although three transceivers174and three antennas178are illustrated inFIG. 1, the client station154-1includes other suitable numbers (e.g., 1, 2, 4, 5, etc.) of transceivers174and antennas178in other embodiments. In some embodiments, the client station154-1includes a higher number of antennas178than transceivers174, and antenna switching techniques are utilized.

The network interface162is implemented using one or more ICs configured to operate as discussed below. For example, the MAC processor166may be implemented on at least a first IC, and the PHY processor170may be implemented on at least a second IC. As another example, at least a portion of the MAC processor166and at least a portion of the PHY processor170may be implemented on a single IC. For instance, the network interface162may be implemented using an SoC, where the SoC includes at least a portion of the MAC processor166and at least a portion of the PHY processor170.

In an embodiment, the host processor158includes a processor configured to execute machine readable instructions stored in a memory device (not shown) such as a RAM, a ROM, a flash memory, etc. In an embodiment, the host processor158may be implemented, at least partially, on a first IC, and the network device162may be implemented, at least partially, on a second IC. As another example, the host processor158and at least a portion of the network interface162may be implemented on a single IC.

In various embodiments, the MAC processor166and the PHY processor170of the client device154-1are configured to generate data units, and process received data units, that conform to the WLAN communication protocol or another suitable communication protocol. For example, the MAC processor166may be configured to implement MAC layer functions, including MAC layer functions of the WLAN communication protocol, and the PHY processor170may be configured to implement PHY functions, including PHY functions of the WLAN communication protocol. The MAC processor166may be configured to generate MAC layer data units such as MSDUs, MPDUs, etc., and provide the MAC layer data units to the PHY processor170. The PHY processor170may be configured to receive MAC layer data units from the MAC processor166and encapsulate the MAC layer data units to generate PHY data units such as PPDUs for transmission via the antennas178. Similarly, the PHY processor170may be configured to receive PHY data units that were received via the antennas178, and extract MAC layer data units encapsulated within the PHY data units. The PHY processor170may provide the extracted MAC layer data units to the MAC processor166, which processes the MAC layer data units.

The PHY processor170is configured to downconvert one or more RF signals received via the one or more antennas178to one or more baseband analog signals, and convert the analog baseband signal(s) to one or more digital baseband signals, according to an embodiment. The PHY processor170is further configured to process the one or more digital baseband signals to demodulate the one or more digital baseband signals and to generate a PPDU. The PHY processor170includes amplifiers (e.g., an LNA, a power amplifier, etc.), an RF downconverter, an RF upconverter, a plurality of filters, one or more ADCs, one or more DACs, one or more DFT calculators (e.g., an FFT calculator), one or more IDFT calculators (e.g., an IFFT calculator), one or more modulators, one or more demodulators, etc.

The PHY processor170is configured to generate one or more RF signals that are provided to the one or more antennas178. The PHY processor170is also configured to receive one or more RF signals from the one or more antennas178.

The MAC processor166is configured to control the PHY processor170to generate one or more RF signals by, for example, providing one or more MAC layer data units (e.g., MPDUs) to the PHY processor170, and optionally providing one or more control signals to the PHY processor170, according to some embodiments. In an embodiment, the MAC processor166includes a processor configured to execute machine readable instructions stored in a memory device (not shown) such as a RAM, a ROM, a flash memory, etc. In an embodiment, the MAC processor166includes a hardware state machine.

In an embodiment, each of the client stations154-2and154-3has a structure that is the same as or similar to the client station154-1. Each of the client stations154-2and154-3has the same or a different number of transceivers and antennas. For example, the client station154-2and/or the client station154-3each have only two transceivers and two antennas (not shown), according to an embodiment.

PPDUs are sometimes referred to herein as packets. MPDUs are sometimes referred to herein as frames.

FIG. 2Ais a diagram of an example multi-user (MU) ranging measurement exchange200in an MU ranging measurement procedure, according to an embodiment. The diagram200is described in the context of the example network110merely for explanatory purposes. In some embodiments, signals illustrated inFIG. 2Aare generated by other suitable communication devices in other suitable types of wireless networks.

The MU ranging measurement exchange200corresponds to an AP-initiated MU ranging measurement exchange, according to an embodiment. The MU ranging measurement exchange200includes an uplink (UL) null data packet (NDP) frame exchange204, a downlink (DL) NDP transmission portion208, a DL feedback (FB) frame exchange210, and an UL FB frame exchange212. In an embodiment, the uplink UL NDP frame exchange204, the DL NDP transmission portion208, the DL FB frame exchange210, and the UL FB frame exchange212occur within a single transmit opportunity period (TXOP). In another embodiment, the uplink UL NDP frame exchange204, the DL NDP transmission portion208, the DL FB frame exchange210, and the UL FB frame exchange212do not occur within a single TXOP. For example, the uplink UL NDP frame exchange204and the DL NDP transmission portion208occur within a single TXOP, whereas the DL FB frame exchange210and the UL FB frame exchange212occur after the single TXOP (e.g., in another TXOP or in multiple other TXOPs).

In the UL NDP exchange204, a first communication device (e.g., the AP114) transmits a DL PPDU216that includes a trigger frame to cause a group of multiple second communication devices (e.g., client stations154) to simultaneously transmit, as part of an uplink (UL) MU transmission220, UL null data packets (NDPs)224. In an embodiment, the trigger frame in the PPDU216is a type of trigger frame specifically for initiating an MU ranging measurement exchange such as the MU ranging measurement exchange200. The trigger frame in the PPDU216causes multiple client stations154to begin simultaneously transmitting the UL MU transmission220a defined time period after an end of the PPDU216. In an embodiment, the defined time period is a short interframe space (SIFS) as defined by the IEEE 802.11 Standard. In other embodiments, another suitable time period is utilized.

In an embodiment, the UL MU transmission220includes an UL MU multiple input, multiple output (MIMO) transmission having two or more UL NDPs224from multiple client stations154, e.g., STA1, STA2, STA3, and STA4. The two or more of the UL NDPs224are transmitted within a same frequency band via different spatial streams (e.g., MU-MIMO). In another embodiment, the UL MU transmission220includes an UL orthogonal frequency division multiple access (OFDMA) transmission having two or more UL NDPs224from multiple client stations154, e.g., STA1, STA2, STA3, and STA4, in different respective frequency bandwidth portions. In yet another embodiment, three or more UL NDP packets224transmitted using a combination of UL MU-MIMO and UL OFDMA, where at least two NDPs are transmitted using MU-MIMO in a same frequency bandwidth portion via different spatial streams, and at least one NDP is transmitted in at least one other different frequency bandwidth portion. The UL NDPs224include PHY preambles having one or more short training fields (STFs), one or more long training fields (LTFs) and one or more signal fields, in an embodiment. The UL NDPs224omit data portions.

When transmitting the UL NDPs224, each client station154records a time t1,kat which the client station154began transmitting the UL NDP224, where k is an index indicating the particular client station154. Similarly, when the AP114receives each UL NDP224, the AP114records a time t2,kat which the AP114began receiving the UL NDP224.

In some embodiments, when transmitting the UL NDPs224, each of at least some of the client stations154(e.g., client stations154with multiple antennas174) records an angle of departure, AoD1,k, at which the UL NDP224left the antennas178of the client station154. Similarly, when the AP114receives each UL NDP224, the AP114records an angle of arrival, AoA1,k, at which the UL NDP224arrived at the antennas138of the AP114.

FIG. 2Bis a timing diagram of the example MU ranging measurement exchange200ofFIG. 2A. As illustrated inFIG. 2B, each client station154records the time t1,kat which the client station154began transmitting the UL NDP224, and records the AoD1,kat which the UL NDP224left the antennas178of the client station154. Additionally, the AP114records the time t2,kat which the AP114began receiving each UL NDP224, and the AoA1,k, at which each UL NDP224arrived at the antennas138of the AP114.

Referring now toFIGS. 2A and 2B, responsive to the UL MU transmission220, the AP114begins transmitting a DL PPDU228that includes an NDP announcement (NDPA) frame a defined time period after an end of the UL MU transmission220. In an embodiment, the defined time period is SIFS. In other embodiments, another suitable time period is utilized. The NDPA frame in the PPDU228is configured to cause the client stations154to be prepared to receive an NDP from the AP114, according to an embodiment.

The AP114generates a DL PPDU232and begins transmitting the DL PPDU232a defined time period after an end of the DL PPDU228. In an embodiment, the defined time period is SIFS. In other embodiments, another suitable time period is utilized. The DL PPDU232is a MU PPDU that includes DL NDPs236to respective client stations154. In another embodiment, the AP114transmits a single DL NDP236using a SU DL transmission (e.g., the NDP Announcement frame228announces to all receivers that the DL NDP236is following) to the client stations154. The DL NDP(s)236include PHY preamble(s) having one or more STFs, one or more LTFs and one or more signal fields, in an embodiment. The DL NDP(s)236omit data portions. In an embodiment, different DL NDPs236are transmitted in different frequency bandwidth portions (e.g., OFDMA). In some embodiments, two or more of the DL NDPs236are transmitted within a same frequency band (e.g., two or more of the DL NDPs236span the same frequency band) using different spatial streams (e.g., the two or more DL NDPs236are transmitted using MU-MIMO). In another embodiment, a single DL NDP236is broadcast to the client stations154.

When transmitting the DL NDP(s)236, the AP114records a time t3,kat which the AP114began transmitting the DL NDP(s)236. Similarly, when each client station154receives the corresponding DL NDP236, the client station154records a time t4,kat which the client station154began receiving the DL NDP236. As illustrated inFIG. 2B, the AP114records the time t3,kat which the AP114began transmitting the DL NDP236, and the client station154records the time t4,kat which the client station154began receiving the DL NDP236.

In some embodiments, when transmitting the DL NDP236, the AP114records an AoD2,kat which the DL NDP236left the antennas138of the AP114. Similarly, when the client station154receives the DL NDP236, the client station154records an AoA2,kat which the DL NDP236arrived at the antennas178of the client station154.

In some embodiments, the MU ranging measurement exchange200omits the DL PPDU228. For example, the AP114begins transmitting the DL PPDU232a defined time period after an end of the UL MU transmission220. In an embodiment, the defined time period is SIFS. In other embodiments, another suitable time period is utilized.

The DL FB exchange210includes a DL PPDU240(which may be a DL OFDMA transmission or a DL MU-MIMO transmission) having FB frames244for multiple client stations154, e.g., STA1, STA2, STA3, and STA4. The FB frames244are illustrated inFIG. 2Aas being transmitted in different frequency bandwidth portions. In some embodiments, two or more of the FB frames244are transmitted within a same frequency band (e.g., two or more of the FB frames244span the same frequency band) using different spatial streams (e.g., the two or more FB frames244are transmitted using MU-MIMO).

In some embodiments, the DL PPDU240is transmitted a defined time period after an end of the DL PPDU232. In an embodiment, the defined time period is SIFS. In other embodiments, another suitable time period is utilized. In other embodiments, the DL PPDU240is transmitted after some delay. As discussed above, in some embodiments, the DL PPDU240is not transmitted within a same TXOP as the DL PPDU232.

The FB frames244respectively include the recorded times t2,kand t3,k. In some embodiments, each of one or more FB frames244respectively includes (optionally) the recorded angles AoA1,kand AoD2,k. In some embodiments, the FB frames244optionally also include respective channel estimate information determined by the AP114based on reception of the UL NDPs224.

After receipt of the FB frames244, one or more of the client stations154respectively calculate one or more respective of times-of-flight between the AP114and the one or more client stations154using the recorded times t1,k, t2,k, t3,k, and t4,k, according to an embodiment. Any suitable technique, including currently known techniques, may be utilized to calculate a time-of-flight using the recorded times t1,k, t2,k, t3,k, and t4,k. Respective distances between the AP114and the client stations154may be calculated using the calculated times-of-flight, e.g., by respectively multiplying the times-of-flight by the speed of light, according to an embodiment.

In some embodiments, one or more of the client stations154calculates estimated positions of one or more of the client stations using the calculated times-of-flight. For example, the client station154-1uses triangulation techniques to calculate an estimated positions of the client station154-1using the calculated time-of-flight. In some embodiments, the client station154-1calculates an estimated position of the client station also using the recorded angles AoD1,k, AoA1,k, AoD2,k, and AoA2,k. For example, the recorded angles AoD1,k, AoA1,k, AoD2,k, and AoA2,kare used as part of a triangulation algorithm for determining a position of the client station154-1.

Responsive to receipt of the FB frames244, the client stations154generate an UL MU transmission250(which may be an UL OFDMA transmission or an UL MU MIMO transmission) that includes respective ACK frames254from respective client stations, according to an embodiment. The client stations154transmit as part of the UL MU transmission250a defined time period after an end of the DL transmission240. In an embodiment, the defined time period is SIFS. In other embodiments, another suitable time period is utilized. The ACK frames254are illustrated inFIG. 2Aas being transmitted in different frequency bandwidth portions. In some embodiments, two or more of the ACK frames254are transmitted within a same frequency band (e.g., two or more of the ACK frames254span the same frequency band) using different spatial streams (e.g., the two or more ACK frames254are transmitted using MU-MIMO). In some embodiments, the client stations154do not generate and transmit the UL MU transmission250(e.g., the client stations154do not generate and transmit the AC frames254).

In an embodiment, the AP114transmits a DL PPDU260a defined time period after an end of the UL MU transmission250. In an embodiment, the defined time period is SIFS. In other embodiments, another suitable time period is utilized. The PPDU260includes a trigger frame to cause the group of client stations154to simultaneously transmit, as part of an UL MU transmission264, uplink PPDUs268that include ranging measurement feedback. The trigger frame in the PPDU260causes multiple client stations154to begin simultaneously transmitting the UL MU transmission264a defined time period after an end of the PPDU260. In an embodiment, the defined time period is SIFS. In other embodiments, another suitable time period is utilized.

The UL MU transmission264(which may be an UL OFDMA transmission or an UL MU-MIMO transmission) includes UL PPDUs268from multiple client stations154, e.g., STA1, STA2, STA3, and STA4. The UL PPDUs268are illustrated inFIG. 2Aas being transmitted in different frequency bandwidth portions. In some embodiments, two or more of the UL PPDUs268are transmitted within a same frequency band (e.g., two or more of the UL PPDUs268span the same frequency band) using different spatial streams (e.g., the two or more UL PPDUs268are transmitted using MU-MIMO).

The UL PPDUs268correspond to uplink ranging measurement feedback packets. The PPDUs268respectively include the recorded times t1,kand t4,k. In some embodiments, each of one or more PPDUs268respectively includes (optionally) the recorded angles AoD1,kand AoA2,k. In some embodiments, the PPDUs268optionally also include respective channel estimate information determined by the client station154based on reception of the DL NDP236.

In an embodiment, the AP114transmits an acknowledgement to the client stations154after receiving the UL MU transmission264. In other embodiments, however, the AP114does not transmit an acknowledgement after receiving the UL MU transmission264. In an embodiment, an indication in the DL PPDU260indicates whether or not the AP114will transmit an acknowledgement to the client stations154after receiving the UL MU transmission264.

After receipt of the PPDUs268, the AP114calculates respective of times-of-flight between the AP114and the client stations154using the recorded times t1,k, t2,k, t3,k, and t4,k, according to an embodiment. Any suitable technique, including currently known techniques, may be utilized to calculate a time-of-flight using the recorded times t1,k, t2,k, t3,k, and t4,k. Respective distances between the AP114and the client stations154may be calculated using the calculated times-of-flight, e.g., by respectively multiplying the times-of-flight by the speed of light, according to an embodiment.

In some embodiments, the AP114calculates estimated positions of one or more of the client stations using the calculated times-of-flight. For example, the AP114uses triangulation techniques to calculate estimated positions of one or more of the client stations using the calculated times-of-flight. In some embodiments, the AP114calculates estimated positions of one or more of the client stations also using the recorded angles AoD1,k, AoA1,k, AoD2,k, and AoA2,k. For example, the recorded angles AoD1,k, AoA1,k, AoD2,k, and AoA2,kare used as part of a triangulation algorithm for determining positions of communication devices.

In another embodiment, the order, in time, of the DL FB exchange210and the UL FB exchange212is reversed, and the UL FB exchange212occurs before the DL FB exchange210. In some embodiments, the DL FB exchange210is omitted. In some embodiments, the UL FB exchange212is omitted.

FIG. 3Ais a timing diagram of an example MU ranging measurement procedure300, according to an embodiment. The diagram ofFIG. 3Ais described in the context of the example network110merely for explanatory purposes. In some embodiments, signals illustrated inFIG. 3Aare generated by other suitable communication devices in other suitable types of wireless networks.

The MU ranging measurement procedure300begins at a start time and includes a plurality of stages304. In an embodiment, the AP114performs one or more MU ranging measurement exchanges (e.g., the MU ranging measurement exchange200ofFIG. 2Aor another suitable MU ranging measurement exchange) with different sets of client stations154in the stages304. Each stage304includes a time slot308(sometimes referred to herein as an enhanced fine timing measurement (EFTM) service period (SP)). In an embodiment, a first time slot308-1begins at the start time of the MU ranging measurement procedure300. The time slots308occur at an interval.

In an embodiment, the AP114transmits a trigger frame to determine the readiness of a plurality of client stations154to participate in an MU ranging measurement procedure prior to initiating an MU ranging measurement exchange. In an embodiment, a trigger frame to determine the readiness of client stations154is transmitted in each time slot308.FIG. 3Bis a timing diagram330showing an example transmission exchange340within a portion of the time slot308to determine the readiness of client stations154. In other embodiment, however, the transmission exchange340occurs outside of the time slot308.

The AP114generates and transmits a DL PPDU352to the client stations154to poll the client stations154and determine readiness of the client stations154to participate in the MU ranging measurement procedure300. In an embodiment, the DL PPDU352includes a trigger frame. In an embodiment, the trigger frame in the DL PPDU352is a type of trigger frame specifically for polling the client stations154to determine the readiness. In an embodiment, the trigger frame in the DL PPDU352includes information that indicates that the trigger frame is for an MU ranging measurement procedure and further indicates that the trigger frame is for prompting the client stations to transmit, to the AP114, respective ranging measurement readiness packets indicative of readiness of the respective client stations154to participate in the MU ranging measurement procedure.

In response to the reception of the trigger frame in the DL PPDU352, each of the client stations154determines its readiness to participate in the MU ranging measurement procedure with the AP114. In an embodiment, a client station154determines that it is ready to participate in the MU ranging measurement procedure with the AP114if it is not currently communicating with any other communication device (e.g., a communication device different from the AP114). If a client station154determines that it is ready to participate in the MU ranging measurement procedure, the client station154transmits a packet indicative of its readiness to participate in the MU ranging measurement procedure as part of an UL MU transmission356to the AP114in conjunction with one or more other client stations154. In an embodiment, the UL MU transmission356is an UL OFDMA transmission and/or an UL MU-MIMO transmission that includes respective ranging measurement readiness packets from a plurality of client stations154that are ready to participate in the MU ranging measurement procedure. In various embodiments, the ranging measurement readiness packets transmitted by the client stations154include one or more of a quality of service (QoS) null frame, an enhanced fine timing measurement (EFTM) request frame, a power save (PS) poll frame, etc. In another embodiment, the ranging measurement readiness packets transmitted by the client stations154are NDPs.

Based on the reception of the UL MU transmission356, the AP114determines client stations154that are ready to participate in the MU ranging measurement procedure. For instance, in an embodiment, the AP114determines a group of client stations154from among the plurality of client stations154that transmitted respective ranging measurement readiness packets in the UL MU transmission356. In an embodiment, the AP114determines that a client station154is ready to participate in an MU ranging measurement exchange if a corresponding ranging measurement readiness packet transmitted by the client station154is received by the AP114.

In an embodiment, the AP114transmits a trigger frame to prompt a plurality of client stations154to transmit respective requests for participation in an MU ranging measurement procedure.FIG. 4Ais a timing diagram of an example transmission exchange400between an AP114and a plurality of client stations154. The diagram ofFIG. 4Ais described in the context of the example network110merely for explanatory purposes. In some embodiments, signals illustrated inFIG. 4Aare generated by other suitable communication devices in other suitable types of wireless networks.

The AP114generates and transmits a DL PPDU404having a trigger frame configured to prompt a plurality of client stations154to transmit, as part of an UL MU transmission408(e.g., an UL OFDMA transmission and/or an UL MU-MIMO transmission), respective ranging measurement request packets indicative of respective requests for participation in the MU ranging measurement procedure. In an embodiment, the trigger frame in the DL PPDU404is a type of trigger frame specifically for prompting the client stations154to transmit, to the AP114, respective ranging measurement request packets. In an embodiment, the trigger frame in the DL PPDU404includes information that indicates that the trigger frame is for an MU ranging measurement procedure and further indicates that the trigger frame is for prompting the client stations to transmit, to the AP114, respective ranging measurement request packets.

In response to the DL PPDU404, at least some of the plurality of client stations154simultaneously transmit, as part of the UL MU transmission408(e.g., an UL OFDMA transmission and/or an UL MU-MIMO transmission) to the AP114, respective ranging measurement request packets. For instance, at least some of the plurality of client stations154require a ranging measurement procedure and respond to the DL PPDU404by transmitting respective ranging measurement request packets.

In an embodiment, based on the UL MU transmission408, the AP114determines a group of client stations154to participate in the MU ranging measurement procedure. For instance, in an embodiment, the AP114determines the group of client stations154, from among the plurality of client stations154, that transmitted respective ranging measurement request packets. The AP114and the group of client stations154then perform the MU ranging measurement procedure, such as the ranging measurement procedure300as described above with respect toFIG. 3, in an embodiment. In some embodiments, the time between the end of the transmission exchange400and the beginning of the ranging measurement procedure300is SIFS. In other embodiments, the time between the end of the transmission exchange400and the beginning of the ranging measurement procedure300is different from SIFS.

In an embodiment, an AP114is unaware of the client stations154that are present within a transmission range of the AP114and that may potentially be requiring ranging measurement procedures. In one such embodiment, the AP114transmits a first trigger frame in order to determine client stations154that are present within the transmission range of the AP114prior to transmitting a second trigger frame that prompts at least some of the determined client stations154to transmit respective requests for participation in the MU ranging measurement procedure.FIG. 4Bis a timing diagram of an example transmission exchange450between an AP114and a plurality of client stations154. The transmission exchange450is similar to the transmission exchange400described above and like-numbered elements are not discussed in detail for reasons of brevity. In an embodiment, the AP114initiates the transmission exchange450when performing MU ranging measurements with client stations154that are not necessarily associated with the AP114and/or are unknown to the AP114.

The AP114generates and transmits a DL PPDU454having a first trigger frame configured to prompt a plurality of client stations154to transmit, as part of an UL MU NDP transmission458(e.g., an UL OFDMA transmission and/or an UL MU-MIMO transmission), respective NDPs. In an embodiment, the trigger frame in the DL PPDU454includes information that indicates that the trigger frame is for an MU ranging measurement procedure and further indicates that the trigger frame is for prompting the client stations154to transmit, to the AP114, respective NDPs in order to indicate presence of the respective client stations154. In an embodiment, the trigger frame in the DL PPDU454is a broadcast frame.

In response to the DL PPDU454, the client stations154simultaneously transmit, as part of the UL MU transmission458(e.g., an UL OFDMA transmission and/or an UL MU-MIMO transmission) to the AP114, respective NDPs to indicate presence of the respective client stations154. In an embodiment, the respective NDPs transmitted by the respective client stations154are “short” NDPs that do not include any MPDUs. In an embodiment, the respective NDPs transmitted by the respective client stations154are a type of NDP that is not utilized at the AP114for channel sounding and/or for a ranging measurement.

Based on the reception of the UL MU transmission458, the AP114determines the client stations154that are present within its transmission range. For instance, the AP114determines a client station154as present within its transmission range if a corresponding NDP from the client station154was received in the UL MU transmission458. The AP114then transmits a DL PPDU404having a trigger frame configured to prompt at least some of the determined client stations154to transmit, as part of an UL MU transmission408, respective ranging measurement request packets indicative of respective requests for participation in the MU ranging measurement procedure.

FIG. 5is a diagram of an example frame format of a trigger frame500for use in an MU transmission exchange between an AP114and client stations154, according to an embodiment. In an embodiment, the trigger frame500is used to solicit an UL MU transmission from client stations154. In various embodiments, the trigger frame500is a trigger frame included in one or more of the DL PPDU216(FIG. 2A), DL PPDU260(FIG. 2A), DL PPDU352(FIG. 3B), DL PPDU404(FIG. 4A), and/or DL PPDU454(FIG. 4B). In an embodiment, the trigger frame500is generated by the MAC processor126of the network interface122.FIG. 5indicates example lengths (e.g., in terms of octets) of fields of the trigger frame500. In other embodiments, length(s) one or more of the fields has another suitable number length(s). In some embodiments, one or more of the fields are omitted and/or one or more additional fields are included in the trigger frame500.

The trigger frame500includes a frame control field502, a duration field504, a receiver address (RA) field506, a transmitter address (TA) field508, a common information field510, one or more user information fields512, a padding field514, and a frame check sequence (FCS) field516.

The frame control field502includes information that indicates that frame500is a trigger frame configured to prompt a plurality of other communication devices (e.g., multiple client stations154) to simultaneously transmit as part of an UL MU transmission (e.g., OFDMA and/or MU-MIMO). The duration field504includes information that indicates a length of a transmit opportunity period (TXOP) during which the MU transmission exchange will take place, in an embodiment. The RA field506includes an address corresponding to the multiple client stations154that are the target recipients of the trigger frame500. For instance, the RA field506indicates a broadcast address or a multicast address corresponding to the multiple client stations154, in various embodiments. The TA field508includes an address corresponding to the AP114transmitting the trigger frame500. The common information field510includes information that is common to the multiple client stations154. Each of the user information fields512includes information specific to a corresponding client station154. For instance, in an embodiment, the user information field1512-1indicates information specific to client station154-1, the user information field2512-2indicates information specific to client station154-2, etc. The padding field514includes padding bits for the trigger frame500, if any. Padding bits are included in the padding field514to give STAs more time to prepare the UL MU transmission. The FCS field516includes an error detecting code that enables a receiving device to determine whether the trigger frame500was received without any errors.

FIG. 6Ais a diagram of an example format of a common information field600included in the trigger frame500ofFIG. 5. For example, the common information field600corresponds to the common information field510(FIG. 5).FIG. 6Aindicates example lengths (e.g., in bits) of subfields of the common information field600. In other embodiments, one or more of the subfields has another suitable length. In some embodiments, one or more of the subfields are omitted and/or one or more additional subfields are included in the common information field600.

The common information field600includes a trigger type subfield602, a length subfield604, a cascade indication subfield606, a carrier sense (CS) required subfield608, a bandwidth (BW) subfield610, a guard interval (GI) and long training field (LTF) type subfield612, an MU-MIMO LTF mode subfield614, a number of high efficiency long training field (HE-LTF) symbols subfield616, a space-time block coding (STBC) subfield618, a low density parity check (LDPC) extra symbol segment subfield620, an AP transmit power subfield622, a packet extension subfield624, a spatial reuse subfield626, a Doppler subfield628, a high efficiency signal-A (HE-SIG-A) reserved subfield630, a reserved subfield632, and a trigger dependent common information subfield634. In an embodiment, the trigger dependent common information subfield634is omitted from the common information field610.

Referring now toFIGS. 5 and 6A, different variants of trigger frame500correspond to different types of information that are to be solicited from client stations154in an UL MU transmission and/or correspond to different types of MU frame exchange procedures. The trigger type subfield602includes a value indicating a variant of the trigger frame500. In an embodiment, the value of the trigger type subfield602is selected from among a plurality of values corresponding to a plurality of trigger frame variants defined by a communication protocol (e.g., the IEEE 802.11 Standard). In an embodiment, the plurality of trigger values further includes one or more values corresponding to one or more trigger frame variants as utilized in MU ranging measurement procedures ofFIGS. 2A, 2B, 3A, 3B, 4A, and 4B(e.g., trigger frames in DL PPDU216, DL PPDU260, DL PPDU352, DL PPDU404, and/or DL PPDU454).

In an illustrative embodiment, the plurality of trigger frame variants includes any suitable combination of two or more of the following: i) a basic trigger for soliciting an UL MU transmission having basic user data, ii) a beamforming report poll (BRP) trigger for soliciting an UL MU transmission having beamforming training feedback, iii) an MU block acknowledgement request (MU-BAR) trigger for soliciting an UL MU transmission having block acknowledgements, iv) an MU request-to-send (MU-RTS) trigger for soliciting an UL MU transmission having clear-to-send (CTS) frames, v) a buffer status report poll (BSRP) trigger for soliciting an UL MU transmission having information regarding how much user data is buffered at client stations154for transmission to the AP114, vi) a bandwidth query report poll (BQRP) trigger for soliciting an UL MU transmission having bandwidth query reports indicative of channel bandwidth availabilities at client stations154, vii) an NDP feedback report poll (NFRP) trigger for soliciting an UL MU transmission having NDPs as feedback (e.g., trigger frame in PPDU454), viii) a trigger for soliciting an UL MU transmission having ranging measurement readiness packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU352), ix) a trigger for soliciting an UL MU transmission having ranging measurement request packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU404), x) a trigger for soliciting an UL MU transmission having NDPs for an MU ranging measurement procedure (e.g., trigger frame in PPDU216), xi) a trigger for soliciting an UL MU transmission having ranging measurement feedback packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU260), etc.

The length subfield604includes a value indicating a length of packets (e.g., PPDUs, NDPs, etc.) to be transmitted in the UL MU transmission responsive to the trigger frame500. In an embodiment, the value of the length subfield604corresponds to a value that client stations154will include in a legacy signal (L-SIG) field included in packets that will be transmitted by multiple client stations154responsive to the trigger frame500. The cascade indication subfield606includes a value indicating whether the AP will transmit another trigger frame after the UL MU transmission. The CS required subfield608includes a value indicating whether the client stations154are required to use energy detection (ED) methods and the network allocation vector (NAV) to sense the medium and to determine whether to transmit in response to the trigger frame. The BW subfield610includes a value indicating a bandwidth corresponding to the UL MU transmission. The GI and LTF subfield612includes a value indicating i) a GI duration to be used for generating OFDM symbols corresponding to the UL MU transmission, and ii) parameters corresponding to the generation of LTF fields to be included the UL MU transmission. The MU-MIMO LTF mode subfield614includes a value indicating an LTF mode (e.g., single stream pilot HE-LTF mode or masked HE-LTF sequence mode) of the UL MU transmission. The number of HE-LTF symbols subfield616includes a value indicating the number of HE-LTF symbols to be included in UL MU transmission. The STBC subfield618includes a value indicating whether STBC is to be used in the UL MU transmission responsive to the trigger frame500. The LDPC extra symbol segment620includes a value indicating whether an extra OFDM symbol is to be included for LDPC in the UL MU transmission. The AP transmit power subfield622includes a value indicating a combined average power per 20 MHz bandwidth of all transmit antennas used to transmit the trigger frame from the AP114. The packet extension subfield624includes a value indicating a duration of PPDU extension (PE) fields to be added by the client stations154at the end of the UL MU transmission. The spatial reuse subfield626includes a value indicating whether or not spatial reuse techniques, that allow early identification of signals from overlapping BSSs, are allowed for the UL MU transmission. The value included in the Doppler subfield628is used in conjunction with the number of HE-LTF symbols subfield616to indicate the number of HE-LTF symbols to be included in UL MU transmission. The HE-SIG-A reserved subfield630includes a value indicating values to which the client stations154should set reserved bits in the HE-SIG-A2 subfield of the UL MU transmission. The subfield632is reserved, in an embodiment.

Depending on the variant of the trigger frame500(e.g., as specified in the trigger type subfield602) the trigger dependent common information subfield634is optionally present in the common information field600. If present, the format of the trigger dependent common information subfield634is dependent on the variant of the trigger frame500, in at least some embodiments. Further, in an embodiment, one or more of the subfield618, the subfield620, the subfield624, and/or the subfield628are reserved based on the variant of the trigger frame500. For instance, when the trigger frame500is for soliciting an UL MU transmission having respective NDPs from respective client stations154for an MU ranging measurement procedure, subfield618, subfield620, subfield624, and subfield628are reserved from use and the trigger dependent common information subfield634is not present, in an embodiment.

In an embodiment, the trigger type subfield602is not configured to include separate values to indicate each of the trigger variants corresponding to MU ranging measurement procedures. For instance, the trigger type subfield602may include a value indicating that the trigger frame500is a trigger corresponding to MU ranging measurement procedures, and an indication in the trigger dependent common information subfield634further specifies a particular trigger frame variant among a plurality of trigger frame variants corresponding to MU ranging measurement procedures.

FIG. 6Bis a diagram of an example format of a trigger dependent common information subfield640of a common information field600. In an embodiment, the trigger dependent common information field640is included in the common information field600(e.g., the trigger dependent common information subfield640corresponds to the trigger dependent common information subfield634ofFIG. 6A) when the trigger frame500is a trigger corresponding to an MU ranging measurement procedure, in an embodiment. For example, the trigger dependent common information field640is included when the trigger type field602includes a value indicating that the trigger frame500is a trigger corresponding to an MU ranging measurement procedure.FIG. 6Balso indicates example lengths (e.g., in bits) of subfields of the trigger dependent common information field640. In other embodiments, one or more of the subfields has another suitable length(s). In some embodiments, a subfield is omitted and/or one or more additional subfields are included in the trigger dependent common information field640.

The value of the trigger subtype subfield636is selected from among a plurality of values corresponding to a plurality of trigger frame variants such as utilized in MU ranging measurement procedures described above (e.g., two or more trigger frames in DL PPDU216, DL PPDU260, DL PPDU512, DL PPDU404, and/or DL PPDU454, and/or other suitable trigger frames used in MU ranging measurement procedures). In an embodiment, the plurality of trigger frame variants corresponding to the MU ranging measurement procedures includes any suitable combination of two or more of the following: i) a trigger for soliciting an UL MU transmission having ranging measurement readiness packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU312), ii) a trigger for soliciting an UL MU transmission having ranging measurement request packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU404), iii) a trigger for soliciting an UL MU transmission having NDPs for an MU ranging measurement procedure (e.g., trigger frame in PPDU216), iv) a trigger for soliciting an UL MU transmission having ranging measurement feedback packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU260), etc. In another embodiment, the plurality of trigger frame variants corresponding to the MU ranging measurement procedures also includes one or more other suitable trigger frame variants corresponding to the MU ranging measurement procedure. In another embodiment, the plurality of trigger frame variants corresponding to the MU ranging measurement procedures includes two or more other suitable trigger frame variants corresponding to the MU ranging measurement procedure.

The subfield638is reserved, in an embodiment.

In an embodiment, trigger frame variants as utilized in MU ranging measurement procedures are indicated using a combination of the techniques described above with respectFIGS. 6A and 6B. For instance, one or more trigger frame variants among a plurality of variants corresponding to the MU ranging measurement procedures are indicated solely using the trigger type subfield602, while one or more other trigger frame variants among the plurality of variants corresponding to the MU ranging measurement procedures are indicated using a combination of the trigger type subfield602and the trigger subtype subfield636.

In an embodiment, a subfield in the user information field512of a trigger frame500is used to indicate the trigger frame variants as utilized in MU ranging measurement procedures.FIG. 7Aillustrates an example format of a user information field700. In an embodiment, the user information field700is included in the trigger frame500(e.g., as one or more of the user information fields512).FIG. 7Aindicates example lengths (e.g., in bits) of subfields of the user information field700. In other embodiments, one or more of the subfields has another suitable length. In some embodiments, one or more of the subfields are omitted and/or one or more additional subfields are included in the user information field700.

The user information field700includes an association identifier (AID)12subfield702, a resource unit (RU) allocation subfield704, a coding type subfield706, a modulation and coding scheme (MCS) subfield708, a dual carrier modulation (DCM) subfield710, a spatial stream (SS) allocation random access (RA)-RU subfield712, a target receive signal strength indicator (RSSI) subfield714, an acknowledgment (ACK) indication subfield716, and a trigger dependent user information field718. In an embodiment, the trigger dependent user information subfield718is omitted from the user information field512.

The AID12subfield702includes an identifier of a client station154for which the user information field700is intended. In an embodiment, the AID12subfield702includes 12 least significant bits of an AID assigned to the client station154by the AP114. The RU allocation subfield704includes a value corresponding to subcarriers assigned to the client station154for the UL MU transmission responsive to the trigger frame500. The coding type subfield706includes a value indicating a coding type (e.g., binary convolution code (BCC), low density parity check (LDPC) code, etc.) to be used by the client station154for the UL MU transmission. The MCS subfield708includes a value indicating the MCS to be used by the client station154for the UL MU transmission. The DCM subfield710includes a value indicating whether or not DCM is to be utilized by the client station154for the UL MU transmission. In an embodiment, the SS allocation/RA-RU information subfield712includes a value indicating which spatial streams the client station154is to use for transmitting as part of the UL MU transmission. The target RSSI subfield714includes a value indicating a target receive signal power of the UL MU transmission by the client station154. The ACK indication subfield716includes a value indicating whether or not the AP114will transmit an acknowledgement to the client station154in response to receiving a frame from the client station154included in the UL MU transmission.

Depending on the variant of the trigger frame500(e.g., as specified in the trigger type subfield602) the trigger dependent user information subfield718is optionally present in the user information field700. If present, the format of the trigger dependent user information subfield718is dependent on the variant of the trigger frame500, in at least some embodiments. Further, in an embodiment, one or more of the subfield704, subfield706, subfield708, and/or subfield716are reserved from use based on the variant of the trigger frame500. For instance, when the trigger frame500is for soliciting an UL MU transmission for an MU ranging measurement procedure, the subfield704, the subfield706, the subfield708, and the subfield716are reserved from use and the trigger dependent user information subfield718is not present, in an embodiment.

Trigger frames such as those described above may be utilized in random access MU UL transmissions (e.g., an MU UL transmission in which one or more RUs are not assigned to any particular client stations, but rather are available for client stations to contend for use of (e.g., sometimes referred to as “random access RUs”)), in at least some embodiments. In an embodiment, one or more of the triggers as described in MU ranging measurement procedures described above correspond to triggers that prompt client stations to contend for access to one or more random access RUs to transmit as part of the MU UL transmission, and include RU allocations that are specified for random access UL MU transmissions. Such trigger frames are sometimes referred to herein as “random access triggers”. Following the reception of a trigger frame500corresponding to a random access trigger, a client station154uses a corresponding backoff counter to determine whether the RU is idle and available to the client station154to transmit as part of an UL MU transmission. In an embodiment, the backoff counter is initialized to a random integer value and is decremented for every random access trigger that is received by the client station154. When the backoff counter reaches 0, the corresponding client station154responds to the trigger frame500corresponding to a random access trigger in an RU allocated for the random access UL MU transmission.

In various embodiments, one or more of PPDUs352,404, etc., are random access triggers, and one or more of PPDUs356,408, etc., are transmitted by at least some of the client stations154using random access procedures such as described above. In one or more embodiments corresponding to random access triggers, one or more of the subfields of the user information field512of the trigger frames500are coded differently.

In an embodiment corresponding to a random access procedure, specific values in the AID12subfield702(e.g., 0 or 2045) indicate that the user information field700corresponds to one or more random access RUs. For instance, a value of 0 in the AID12subfield702indicates that the user information field700corresponds to a random access UL MU transmission and further indicates that the RU allocation subfield704includes an RU allocation (for random access MU UL transmission) for client stations154that are associated with the AP114. A value of 2045 in the AID12subfield702indicates that the user information field700corresponds to a random access UL MU transmission and further indicates that the RU allocation subfield704includes an RU allocation (for random access MU UL transmission) for client stations154that are not associated with the AP114. In an embodiment, a specific value in the AID12subfield702indicates that the user information field700corresponds to a random access UL MU transmission and further indicates that the RU allocation subfield704includes an RU allocation (for random access MU UL transmission) for all client stations154, irrespective of their association with the AP114. In an embodiment corresponding to a random access UL MU transmission, the SS allocation/RA-RU information subfield712includes a value indicating a number of contiguous RUs allocated for the random access UL MU transmission.

In another embodiment corresponding to a random access procedure, specific values of the AID12subfield702may indicate a trigger frame variant of the trigger frame500in addition to indicating that that the user information field700corresponds to a random access UL MU transmission. For instance, at least some of the trigger frame variants as utilized in MU ranging measurement procedures described above may be indicated using the AID12subfield702, wherein the AID12subfield702further indicates that the trigger frame500corresponds to a random access trigger. In some such embodiments, the trigger type subfield602may indicate that the trigger frame corresponds to a default trigger frame variant (e.g., a basic trigger), while the AID12subfield702indicates a specific trigger subtype corresponding to an MU ranging measurement procedure and further indicates that the trigger frame500corresponds to a random access trigger. In another embodiment, the trigger type subfield602may indicate that the trigger frame500is a trigger corresponding to an MU ranging measurement procedure, while the AID12subfield702indicates a specific trigger subtype corresponding to the MU ranging measurement procedure and further indicates that the trigger frame500corresponds to a random access trigger. In an embodiment, the trigger frame variants that may be indicated in the AID12subfield702include: i) a trigger for soliciting an UL MU transmission having respective ranging measurement readiness packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU312), ii) a trigger for soliciting an UL MU transmission having respective ranging measurement request packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU404), etc.

In an embodiment, a value of 2040 in the AID12subfield702indicates that the trigger frame500i) is a trigger for soliciting an UL MU transmission having respective ranging measurement request packets from respective client stations154, and ii) corresponds to a random access trigger. In an embodiment, a value of 2041 in the AID12subfield702indicates that the trigger frame500i) is a trigger for soliciting an UL MU transmission having respective ranging measurement readiness packets from respective client stations154, and ii) corresponds to a random access trigger.

In an embodiment, a trigger frame, such as the trigger frame500, may include one or more user information fields that correspond to one or more random access RUs and also include one or more other user information fields that do not correspond to random access RUs. For instance, the one or more other user information fields include indications of RUs assigned to specific client stations154.

In an embodiment, trigger dependent user information subfields718of trigger frames500corresponding to trigger frame variants that are not specifically associated with an MU ranging measurement procedure (e.g., a basic trigger, an NFRP trigger, etc.) may be used to indicate a trigger frame variant corresponding to an MU ranging measurement procedure.

FIGS. 7B and 7Cillustrate example formats of trigger dependent user information subfields720and730, respectively. In an embodiment, the example formats correspond to a trigger dependent user information field718of a trigger frame500corresponding to a basic trigger frame variant.FIGS. 7B and 7Calso indicate example lengths (e.g., in bits) of subfields of the trigger dependent user information subfields720and730, respectively. In other embodiments, one or more of the subfields has another suitable length. In some embodiments, one or more of the subfields are omitted and/or one or more additional subfields are included in the trigger dependent user information subfields720and730.

The ranging measurement request subfield732indicates a format of the trigger dependent user information field720or730. In an embodiment, a value of 1 in the ranging measurement request subfield732indicates that the trigger dependent user information subfield includes information corresponding to a ranging measurement procedure. A value of 0 in the ranging measurement request subfield732indicates that the trigger dependent user information subfield includes different information.

FIG. 7Bcorresponds to a trigger dependent user information subfield720with the ranging measurement request subfield732set to 0. An MPDU MU spacing factor subfield734includes a value that is used at the client station154to determine a minimum duration between transmissions of two consecutive MPDUs by the client station154in an UL MU transmission responsive to the trigger frame500. A traffic identifier (TID) aggregation limit subfield736includes a value that indicates a number of MPDUs allowed in an aggregated MPDU (A-MPDU) transmitted by the client station154in the UL MU transmission and, further specifies a maximum number of TIDs that can be included in the A-MPDU. A preferred access category (AC) subfield738includes a value indicating a lowest AC (e.g., best effort, background, video, voice, etc.) that is recommended for aggregation of MPDUs in the A-MPDU transmitted by the client station154in the UL MU transmission.

FIG. 7Ccorresponds to a trigger dependent user information subfield730with the ranging measurement request subfield set to 1. The value of the trigger subtype subfield740is selected from among a plurality of values corresponding to a plurality of trigger frame variants as utilized in MU ranging measurement procedures described above (e.g., trigger frames in DL PPDU216, DL PPDU260, DL PPDU312, DL PPDU404, and/or DL PPDU454). In an embodiment, the plurality of trigger frame variants corresponding to the MU ranging measurement procedure includes any suitable combination of two or more of the following: i) a trigger for soliciting an UL MU transmission having ranging measurement readiness packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU312), ii) a trigger for soliciting an UL MU transmission having ranging measurement request packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU404), iii) a trigger for soliciting an UL MU transmission having NDPs for an MU ranging measurement procedure (e.g., trigger frame in PPDU216), iv) a trigger for soliciting an UL MU transmission having ranging measurement feedback packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU260), etc. The subfields742and744are reserved, in an embodiment.

In an embodiment, trigger frame variants as utilized in MU ranging measurement procedures ofFIGS. 2A, 2B, 3A, 3B, 4A, and 4Bare indicated using a combination of two or more of the techniques described above with respectFIGS. 6A, 6B, 7A, 7B, and 7C. For instance, one or more trigger frame variants among the plurality of variants corresponding to the MU ranging measurement procedures are indicated using a combination of the trigger type subfield602and the trigger dependent common information subfield634, and one or more other trigger frame variants among the plurality of variants corresponding to the MU ranging measurement procedures are indicated using the trigger dependent user information subfield718or the AID subfield702.

FIG. 7Dillustrates another example format of a trigger dependent user information subfield750, according to an embodiment. In an embodiment, the example format ofFIG. 7Dcorresponds to a trigger dependent user information field718of a trigger frame500corresponding to an NFRP trigger frame variant.FIG. 7Dalso indicates example lengths (e.g., in bits) of subfields of the trigger dependent user information subfield750. In other embodiments, one or more of the subfields has another suitable length. In some embodiments, one or more of the subfields are omitted and/or one or more additional subfields are included in the trigger dependent user information subfield750.

As described above with respect toFIG. 5, an NFRP trigger is used to request NDPs from client stations154as feedback. In an embodiment, for instance, with reference toFIG. 4B, an NFRP trigger in the DL PPDU454may be used to solicit the UL MU NDP transmission458, from client stations154, that includes respective NDPs indicating presence of the respective client stations154. In an embodiment, an NFRP trigger may additionally be used to solicit an UL MU transmission having respective NDPs indicating readiness of the respective client stations154for an MU ranging measurement procedure. For instance, an NFRP trigger may be included in the DL PPDU352, as described above with respect toFIG. 3B, to prompt the client stations154to transmit, to the AP114, respective NDPs (in the UL MU transmission356) indicative of readiness of the respective client stations154for an MU ranging measurement procedure. In an embodiment, the NFRP trigger may additionally be used for one or more other trigger frame variants corresponding to MU ranging measurement procedures described above.

A feedback type subfield760includes a value that indicates a variant of and/or a procedure corresponding to the trigger frame500. The value of the feedback type subfield760is selected from among a plurality of values, including values corresponding to a plurality of trigger frame variants as utilized in MU ranging measurement procedures. In an embodiment, the plurality of trigger frame variants corresponding to the MU ranging measurement procedure includes two or more of: i) a trigger for soliciting an UL MU transmission having ranging measurement readiness packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU312), ii) a trigger for soliciting an UL MU transmission having ranging measurement request packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU404), iii) a trigger for soliciting an UL MU transmission having NDPs for an MU ranging measurement procedure (e.g., trigger frame in PPDU216), iv) a trigger for soliciting an UL MU transmission having ranging measurement feedback packets for an MU ranging measurement procedure (e.g., trigger frame in PPDU260), v) a trigger for soliciting an UL MU transmission having respective NDPs indicating presence of the respective client stations154(e.g., trigger frame in PPDU454), etc.

The feedback size subfield762indicates a size of ranging measurement feedback. The scheduling type subfield764indicates a schedule type of MU NDP ranging measurement, e.g., Type 1 or Type 2 STA schedule, secure or unsecure ranging schedule, etc. The group identifier (ID) subfield766includes a value indicating a group ID corresponding to the client stations154from which the NDPs are being solicited in the UL MU transmission. In an embodiment, the group is established through negotiation and members of a group have a same set of ranging measurement capabilities. The starting STA subfield768indicates a first AID of a range of AIDs corresponding to the client stations154that are scheduled to transmit in the UL MU transmission. The target RSSI subfield770includes a value indicating a target receive signal power of the UL MU transmission by the client stations154. The resource request buffer threshold subfield774is used for a buffer status report of a STA, which is reserved in the trigger frame500(e.g., the subfield774is not used in ranging measurements), according to an embodiment.

In an embodiment, trigger frame variants as utilized in MU ranging measurement procedures ofFIGS. 2A, 2B, 3A, 3B, 4A, and 4Bare indicated using a combination of two or more of the techniques described above with respectFIGS. 6A, 6B, 7A, 7B, 7C, and 7D. For instance, one or more trigger frame variants among the plurality of variants corresponding to the MU ranging measurement procedures are indicated using a combination of the trigger type subfield602and the trigger dependent common information subfield634, and one or more other trigger frame variants among the plurality of variants corresponding to the MU ranging measurement procedures are indicated using a feedback type subfield760in an NFRP trigger.

In an embodiment, the user information field512includes information that is used to authenticate an UL MU transmission for a ranging measurement procedure from client stations154.FIG. 8Aillustrates an example user information field800of the trigger frame500, in an embodiment.FIG. 8Aindicates example lengths (e.g., in bits) of subfields of the user information field512. In other embodiments, one or more of the subfields has another suitable length. In some embodiments, one or more of the subfields are omitted and/or one or more additional subfields are included in the user information field800. Some subfields in the user information field800are similar to corresponding subfields in the user information field700illustrated inFIG. 7A, and like-numbered elements are not described in detail merely for purposes of brevity.

The sequence authentication code (SAC) subfield802includes an SAC value that is used for authenticating a trigger frame and/or NDPs transmitted in response to the trigger frame. For example, in an embodiment wherein the trigger frame500is a trigger for soliciting an UL MU transmission having respective NDPs from respective client stations154for an MU ranging measurement procedure (e.g., trigger in DL PPDU216), the SAC subfield indicates respective LTF formats to be used by the respective client stations154for transmission of respective NDPs. In an embodiment, an AP114that receives an NDP transmitted by a client station154, in response to a trigger frame500, authenticates the NDP by comparing the LTF format of the NDP with the indication in the SAC subfield802.

In an embodiment where the SAC value has a number of bits that is larger than a number of bits that can be accommodated in the SAC subfield802, at least some bits of the SAC may be indicated in the common information field510.FIGS. 8B and 8Cillustrates an example format of a trigger dependent common information subfield810(of a common information field510) and an example format of a user information field820. Some subfields in the trigger dependent common information subfield810and the user information field820are similar to corresponding subfields in the trigger dependent common information subfield640illustrated inFIG. 6Band the user information field700ofFIG. 7A, and like-numbered elements are not described in detail merely for purposes of brevity. In another embodiment, part of the SAC field is in the Trigger dependent User Info field, which can be one-octet long, two-octet long, or have another suitable length. In another embodiment, the whole SAC field is in the Trigger dependent User Info field, which can be two-octet long, three-octet long, or have another suitable length.

Referring now toFIG. 8B, the trigger subtype subfield636includes a value indicating the trigger frame variant as utilized in an MU ranging measurement procedure, as described above with respect toFIG. 6B. An SAC most significant bits (MSB) subfield806includes a plurality of most significant bits of an SAC value. Referring now toFIG. 8C, an SAC least significant bits (LSB) subfield808includes a plurality of least significant bits of the SAC value.

In an embodiment where all client stations154share a common SAC, the entirety of the SAC is indicated in a subfield of the trigger dependent common information subfield810.

FIG. 9is a flow diagram of an example method900for performing a ranging measurement procedure, according to an embodiment. In some embodiments, the AP114(e.g., the network interface device122) ofFIG. 1is configured to implement the method900. The method900is described in the context of the AP114merely for explanatory purposes and, in other embodiments, the method900is implemented by another suitable device. For instance, in an embodiment, the client station154(e.g., network interface device162) ofFIG. 1is configured to implement the method900.

The method900is implemented in conjunction with the procedures, frame formats, etc., described above in connection with one or more ofFIGS. 2A, 2B, 3A, 3B, 4A, 4B, 5, 6A, 6B, 7A-7D, and 8A-8C, in various embodiments. In other embodiments, the method900is implemented in conjunction with suitable procedures, frame formats, etc., different than those discussed above.

At block904, the AP114generates (the network interface device122generates, the MAC processor126generates, etc.) a first trigger frame that includes one or more trigger type information fields for indicating a type of MU frame exchange to which a trigger frame instance corresponds. In an embodiment, the first trigger frame is generated to include one or more trigger type information fields set to corresponding values that indicate i) the first trigger frame is for an MU ranging measurement procedure, and ii) the first trigger frame is for prompting multiple client stations154from among a plurality of client stations154to simultaneously transmit first NDPs to the AP114as part of a first MU transmission associated with the MU ranging measurement procedure. In an embodiment, the one or more trigger type information fields are one or more of a trigger type subfield, a trigger subtype subfield, a feedback type subfield, an AID subfield, etc., as described above in the context ofFIGS. 6A, 6B, 7A-7D, and 8A-8C. In other embodiments, at least one of the one or more trigger type information fields are one or more suitable fields/subfields different than those described above in the context ofFIGS. 6A, 6B, 7A-7D, and 8A-8C.

At block908, the AP114transmits (the network interface device122transmits, the PHY processor130transmits, etc.) the first trigger frame to prompt the multiple client stations154to transmit first NDPs as part of the first MU transmission. For instance, as described above with respect toFIG. 2A, the first trigger frame is included in a DL PPDU216and transmitted to multiple client stations154.

At block912, the AP114receives (the network interface device122receives, the PHY processor130receives, etc.) the first MU transmission having multiple first NDPs transmitted simultaneously by at least some of the multiple client stations154. The multiple first NDPs are for the MU ranging measurement procedure and are transmitted by the at least some of the multiple client stations154in response to the first trigger frame. For instance, as described above with respect toFIG. 2A, the multiple first NDPs are included in an UL MU transmission220.

At block916, the AP114transmits (the network interface device122transmits, the PHY processor130transmits, etc.) a second NDP to the multiple client stations154as part of the MU ranging measurement procedure.

At block920, the AP114generates (the network interface device122generates, the MAC processor126generates, etc.) a second trigger frame for the MU ranging measurement procedure. In an embodiment, one or more trigger type information fields in the second trigger frame include one or more respective values that indicate the second trigger frame includes one or more trigger type information fields set to corresponding values that indicate i) the second trigger frame is for an MU ranging measurement procedure, and ii) the second trigger frame is for prompting the multiple second communication devices to simultaneously transmit feedback packets to the first communication device as part of a second MU transmission associated with the MU ranging measurement procedure. In an embodiment, the one or more trigger type information fields are one or more of a trigger type subfield, a trigger subtype subfield, a feedback type subfield, an AID subfield, etc., such as described above in the context ofFIGS. 6A, 6B, 7A-7D, and 8A-8C. In other embodiments, at least one of the one or more trigger type information fields are one or more suitable fields/subfields different than those described above in the context ofFIGS. 6A, 6B, 7A-7D, and 8A-8C.

At block924, the AP114transmits (the network interface device122transmits, the PHY processor130transmits, etc.) the second trigger frame to prompt the multiple client stations154to transmit feedback packets as part of the second MU transmission. For instance, as described above with respect toFIG. 2A, the second trigger frame is included in a DL PPDU260and transmitted to multiple client stations154.

At block928, the AP114receives (the network interface device122receives, the PHY processor130receives, etc.) the second MU transmission having multiple feedback packets transmitted simultaneously by at least some of the client stations154, the multiple feedback packets including ranging measurement feedback information. In an embodiment, the ranging measurement feedback information includes one or more of timing and angle of arrival/departure information corresponding to i) transmission of the first NDPs from the client stations154, and ii) reception of the second NDP at the client stations154(e.g., t1,k, t4,k., AoD1,k, AoA2,k, etc.). In an embodiment, the ranging measurement feedback information includes: times corresponding to transmission of the multiple first NDPs transmitted simultaneously by at least some of the multiple second communication devices; and times corresponding to reception of the second NDP at the at least some of the multiple second communication devices.

At block932, the AP114calculates (the network interface device122calculates, the MAC processor126calculates, etc.) respective distances between the AP114and at least some of the multiple client stations154using the measurement feedback information received in the second MU transmission. For instance, as described above in the context ofFIGS. 2A and 2B, the AP114calculates respective times of flights to determine the respective distances and/or uses a triangulation algorithms to determine the respective positions of the client stations154.

In another embodiment, the method900also includes: generating, at the first communication device, a third trigger frame according to the trigger frame format, wherein generating the third trigger frame includes: setting the one or more trigger type information fields of the third trigger frame to a third one or more respective values that indicates i) the third trigger frame is for an MU ranging measurement procedure, and ii) the third trigger frame is for prompting the plurality of second communication devices to simultaneously transmit ranging measurement request packets to the first communication device as part of a third MU transmission associated with the MU ranging measurement procedure; transmitting, by the first communication device, the third trigger frame to prompt at least some second communication devices to transmit ranging measurement request packets as part of the third MU transmission; and determining, at the first communication device and using information in the ranging measurement request packets, a group of second communication devices, from among the plurality of second communication devices, that are requesting to participate in the MU ranging measurement procedure.

In another embodiment, the method900also includes: generating, at the first communication device, a third trigger frame according to the trigger frame format, wherein generating the third trigger frame includes: setting the one or more trigger type information fields of the third trigger frame to a third one or more respective values that indicates i) the third trigger frame is for an MU ranging measurement procedure, and ii) the third trigger frame is for prompting the multiple second communication devices to simultaneously transmit ranging measurement readiness packets to the first communication device as part of a third MU transmission associated with the MU ranging measurement procedure; transmitting, by the first communication device, the third trigger frame to prompt at least some second communication devices to transmit ranging measurement readiness packets as part of the third MU transmission; and determining, at the first communication device and using information in the ranging measurement readiness packets, a group of second communication devices, from among the plurality of second communication devices, that are ready to participate in the MU ranging measurement procedure.

In an embodiment, the trigger frame format includes: i) a trigger type field for indicating the type of MU frame exchange, and ii) a trigger subtype subfield in a trigger-type dependent field when the trigger type field is set to a first value that indicates the trigger frame is for the MU ranging measurement procedure; generating the first trigger frame includes: setting the trigger type field of the first trigger frame to the first value, and setting the trigger subtype subfield of the first trigger frame to a second value indicating that the first trigger frame is for prompting the multiple second communication devices to simultaneously transmit first NDPs to the first communication device as part of the first MU transmission associated with the MU ranging measurement procedure; and generating the second trigger frame includes: setting the trigger type field of the second trigger frame to the first value, and setting the trigger subtype subfield of the second trigger frame to a third value indicating that the second trigger frame is for prompting the multiple second communication devices to simultaneously transmit feedback packets to the first communication device as part of the second MU transmission associated with the MU ranging measurement procedure.

In another embodiment, the method900also includes: generating, at the first communication device, a third trigger frame according to the trigger frame format, wherein generating the third trigger frame includes: setting the trigger type field of the third trigger frame to the first value, and setting the trigger subtype subfield of the third trigger frame to a third value indicating that the third trigger frame is for prompting the plurality of second communication devices to simultaneously transmit ranging measurement request packets to the first communication device as part of a third MU transmission associated with the MU ranging measurement procedure; transmitting, by the first communication device, the third trigger frame to prompt at least some second communication devices to transmit ranging measurement request packets as part of the third MU transmission; and determining, at the first communication device and using information in the ranging measurement request packets, a group of second communication devices, from among the plurality of second communication devices, that are requesting to participate in the MU ranging measurement procedure.

In another embodiment, the method900further includes: generating, at the first communication device, a third trigger frame according to the trigger frame format, wherein generating the third trigger frame includes: setting the trigger type field of the third trigger frame to the first value, and setting the trigger subtype subfield of the third trigger frame to a third value indicating that the third trigger frame is for prompting the multiple second communication devices to simultaneously transmit ranging measurement readiness packets to the first communication device as part of a third MU transmission associated with the MU ranging measurement procedure; transmitting, by the first communication device, the third trigger frame to prompt at least some second communication devices to transmit ranging measurement readiness packets as part of the third MU transmission; and determining, at the first communication device and using information in the ranging measurement readiness packets, a group of second communication devices, from among the plurality of second communication devices, that are ready to participate in the MU ranging measurement procedure.

FIG. 10is a flow diagram of an example method1000for performing a ranging measurement procedure, according to an embodiment. In some embodiments, the client station154(e.g., the network interface device162) ofFIG. 1is configured to implement the method1000. The method1000is described, however, in the context of the client station154merely for explanatory purposes and, in other embodiments, the method1000is implemented by another suitable device. For instance, in an embodiment, the AP114(e.g., the network interface device122) ofFIG. 1is configured to implement the method1000.

The method1000is implemented in conjunction with the procedures, frame formats, etc., described above in connection with one or more ofFIGS. 2A, 2B, 3A, 3B, 4A, 4B, 5, 6A, 6B, 7A-7D, and 8A-8C, in various embodiments. In other embodiments, the method1000is implemented in conjunction with suitable procedures, frame formats, etc., different than those discussed above.

At block1004, the client station154receives (the network interface device162receives, the PHY processor170receives, etc.) a first trigger frame, from an AP114, that includes one or more trigger type information fields for indicating a type of MU frame exchange to which a trigger frame instance corresponds. In an embodiment, the first trigger frame includes one or more trigger type information fields set to corresponding values that indicate i) the first trigger frame is for an MU ranging measurement procedure, and ii) the first trigger frame is for prompting multiple client stations154from among a plurality of client stations154to simultaneously transmit first NDPs to the AP114as part of a first MU transmission associated with the MU ranging measurement procedure. In an embodiment, the one or more trigger type information fields are one or more of a trigger type subfield, a trigger subtype subfield, a feedback type subfield, an AID subfield, etc., as described above in the context ofFIGS. 6A, 6B, 7A-7D, and 8A-8C. In other embodiments, at least one of the one or more trigger type information fields are one or more suitable fields/subfields different than those described above in the context ofFIGS. 6A, 6B, 7A-7D, and 8A-8C.

At block1008, the client station154transmits (the network interface device162transmits, the PHY processor170transmits, etc.), to the AP114, a first NDP as part of the first MU transmission in response to the first trigger frame. In an embodiment, as described above with respect toFIG. 2A, the first NDP is included in an UL MU transmission220. In an embodiment, as described above with respect toFIGS. 2A and 2B, the client station154records timing information and/or angle of departure information corresponding to the transmission of the first NDP.

At block1012, the client station154receives (the network interface device162receives, the PHY processor170receives, etc.), from the AP114, a second NDP as part of the MU ranging measurement procedure. In an embodiment, as described above with respect toFIGS. 2A and 2B, the client station154records timing information and/or angle of arrival information corresponding to the reception of second NDP.

At block1016, the client station154receives (the network interface device162receives, the PHY processor170receives, etc.), from the AP114, a second trigger frame according to the trigger frame format, wherein the second trigger frame includes the one or more trigger type information fields set to a second one or more respective values that indicates that i) the second trigger frame is for an MU ranging measurement procedure, and ii) the second trigger frame is for prompting the client stations154to simultaneously transmit respective feedback packets to the AP114as part of a second MU transmission associated with the MU ranging measurement procedure. In an embodiment, the one or more trigger type information fields are one or more of a trigger type subfield, a trigger subtype subfield, a feedback type subfield, an AID subfield, etc., as described above in the context ofFIGS. 6A, 6B, 7A-7D, and 8A-8C. In other embodiments, at least one of the one or more trigger type information fields are one or more suitable fields/subfields different than those described above in the context ofFIGS. 6A, 6B, 7A-7D, and 8A-8C.

At block1020, the client station154transmits (the network interface device162transmits, the PHY processor170transmits, etc.), to the AP114, a feedback packet as part of the second MU transmission in response to the second trigger frame, the feedback packet including ranging measurement feedback information, wherein the ranging measurement feedback information is useable at the second communication device to calculate a distance between the first communication device and the second communication device. In an embodiment, the ranging measurement feedback information includes one or more of timing and angle of arrival/departure information corresponding to transmission of the first NDPs and reception of the second NDP (e.g., t1,k, t4,k., AoD1,k, AoA2,k, etc.). In an embodiment, the ranging measurement feedback information includes: a time corresponding to transmission of the first NDP, from the first communication device, as part of the first MU transmission in response to the first trigger frame; and a time corresponding to reception of the second NDP at the first communication device.

In an embodiment, the method1000further comprises: receiving, at the first communication device and from the second communication device, a third trigger frame according to the trigger frame format, wherein the third trigger frame includes: the one or more trigger type information fields of the third trigger frame set to a third one or more respective values that indicates i) the third trigger frame is for an MU ranging measurement procedure, and ii) the third trigger frame is for prompting the first communication device and the one or more third communication devices to simultaneously transmit ranging measurement request packets to the second communication device as part of a third MU transmission associated with the MU ranging measurement procedure; and transmitting, from the first communication device to the second communication device, a ranging measurement request packet as part of the third MU transmission.

In another embodiment, the method1000further comprises: receiving, at the first communication device and from the second communication device, a third trigger frame according to the trigger frame format, wherein the third trigger frame includes: the one or more trigger type information fields of the third trigger frame set to a third one or more respective values that indicates i) the third trigger frame is for an MU ranging measurement procedure, and ii) the third trigger frame is for prompting the first communication device and the one or more third communication devices to simultaneously transmit ranging measurement readiness packets to the second communication device as part of a third MU transmission associated with the MU ranging measurement procedure; and transmitting, from the first communication device to the second communication device, a ranging measurement readiness packet as part of the third MU transmission.

In another embodiment, the trigger frame format includes: i) a trigger type field for indicating the type of MU frame exchange, and ii) a trigger subtype subfield in a trigger-type dependent field when the trigger type field is set to a first value that indicates the trigger frame is for the MU ranging measurement procedure; the first trigger frame includes: the trigger type field set to the first value, and the trigger subtype subfield set to a second value indicating that the first trigger frame is for prompting the first communication device and the one or more third communication devices to simultaneously transmit respective first NDPs to the second communication device as part of the first MU transmission associated with the MU ranging measurement procedure; and the second trigger frame includes: the trigger type field set to the first value, and the trigger subtype subfield set to a third value indicating that the second trigger frame is for prompting the first communication device and the one or more third communication devices to simultaneously transmit feedback packets to the second communication device as part of the second MU transmission associated with the MU ranging measurement procedure.

In another embodiment, the method1000further includes: receiving, at the first communication device from the second communication device, a third trigger frame according to the trigger frame format, wherein the third trigger frame includes: the trigger type field set to the first value, and the trigger subtype subfield set to a third value indicating that the third trigger frame is for prompting the first communication device and the one or more third communication devices to simultaneously transmit ranging measurement request packets to the second communication device as part of a third MU transmission associated with the MU ranging measurement procedure; and transmitting, from the first communication device to the second communication device, a ranging measurement request packet as part of the third MU transmission.

In another embodiment, the method1000further includes: receiving, at the first communication device from the second communication device, a third trigger frame according to the trigger frame format, wherein the third trigger frame includes: the trigger type field set to the first value, and the trigger subtype subfield set to a third value indicating that the third trigger frame is for prompting the first communication device and the one or more third communication devices to simultaneously transmit ranging measurement readiness packets to the second communication device as part of a third MU transmission associated with the MU ranging measurement procedure; and transmitting, from the first communication device to the second communication device, a ranging measurement readiness packet as part of the third MU transmission.

At least some of the various blocks, operations, and techniques described above may be implemented utilizing hardware, a processor executing firmware instructions, a processor executing software instructions, or any combination thereof. When implemented utilizing a processor executing software or firmware instructions, the software or firmware instructions may be stored in any computer readable memory such as on a magnetic disk, an optical disk, or other storage medium, in a RAM or ROM or flash memory, processor, hard disk drive, optical disk drive, tape drive, etc. The software or firmware instructions may include machine readable instructions that, when executed by one or more processors, cause the one or more processors to perform various acts.