English:
[0001] Aspects of this disclosure relate generally to wireless communications, and more particularly to wireless local area network (WLAN) access point (AP) positioning and navigation systems.
[0002] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, data, and so on. Typical wireless communication systems are multiple-access systems capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). One class of such multiple-access systems is generally referred to as wireless location area networks (WLANs), such as "Wi-Fi," and includes different members of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless protocol family. Generally, a Wi-Fi communication system can simultaneously support communication for multiple wireless devices, such as wireless stations (STAs). Each STA communicates with one or more access points (APs) via transmissions on the downlink and the uplink. The downlink (DL) refers to the communication link from the APs to the STAs, and the uplink (UL) refers to the communication link from the STAs to the APs.
[0003] Modern navigation systems have typically used satellite-based global positioning system (GPS) for position determination. However, the recent proliferation of WLAN (e.g., Wi-Fi) access points has made it possible for navigation systems to use these access points for position determination, especially in urban areas where there are usually large concentrations of WLAN access points. WLAN navigation systems can be advantageous over GPS navigation systems because of limitations of GPS signal coverage. For example, while GPS signals may not be readily available inside a shopping mall, wireless signals generated by WLAN access points inside the shopping mall would be more readily detectable by a STA.
[0004] More specifically, for WLAN navigation systems, the locations of the WLAN access points are used as reference points from which well-known trilateration techniques can determine the location (e.g., absolute location and/or relative location) of a wireless device (e.g., a Wi-Fi-enabled cell phone, laptop, or tablet computer). The wireless device can use the round trip time (RTT) of signals transmitted to and from the access points to calculate the distances between the wireless device and the access points. Once these distances are calculated, the location of the wireless device can be estimated using trilateration techniques.
[0005] One procedure for determining RTT captures the amount of time between the transmission of a unicast packet, such as a data packet or request-to-send (RTS), by STA to an AP and the reception of the appropriate response packet, which may be an acknowledgement (ACK) or clear-to-send (CTS), as measured by the STA. RTT is typically measured in nanoseconds.
[0006] Some chip designs may allow recording of the time of departure (TOD), from the STA and also time of arrival (TO A) at the STA, using timestamps. The timestamps permit measurement of RTT. This method may be referred to as an RTS/CTS-based RTT procedure (also referred to herein as a non-fine timing measurement (FTM) procedure).
[0007] However, in measuring RTT there is a variable amount of turnaround time delay involved at the AP, or receiving node, that needs to be accounted for before the RTT may be used for ranging calculations. These ranging calculations using RTT are made by extracting the time of flight between the STA and the AP, which requires knowledge of the turn-around calibration factor (TCF). TCF may be implementation specific and may depend on the short interframe space (SIFS), time of arrival uncertainty, and other delays at the AP. The TCF varies depending on the chipset used by the AP.
[0008] Another method for determining the range between nodes is often referred to as the fine timing measurement (FTM) protocol. Based on FTM, a STA exchanges FTM messages with the AP and then receives timing information (e.g., timestamps corresponding to arrival and departure times of the FTM messages at the AP) from the AP. The STA then computes its range to the AP based on the timing information.
[0009] Aspects of the present disclosure include a method, a wireless station, and a computer-readable medium for assisting or otherwise performing position determination based on both fine timing measurement (FTM)-based round trip time (RTT) measurements and non-FTM-based RTT measurements.
[0010] For example, in one aspect, a method includes performing, by a wireless station a fine timing measurement (FTM) procedure with each of one or more FTM-enabled access points (APs) to obtain a respective one or more FTM-based round-trip time (RTT) measurements between the wireless station and each of the one or more FTM- enabled APs. The FTM procedure may include: (i) exchanging at least one FTM message with an FTM-enabled AP of the one or more FTM-enabled APs; and (ii) calculating an FTM-based RTT measurement of the one or more FTM-based RTT measurements based on the exchanging of the at least one FTM message. The method also includes performing a non-FTM procedure with each of one or more non-FTM- enabled APs to obtain a respective one or more non-FTM-based RTT measurements, where the non-FTM procedure includes: (i) transmitting a non-FTM message from the first wireless station to a non-FTM-enabled AP of the one or more non-FTM-enabled APs; (ii) receiving a non-FTM response message from the non-FTM-enabled AP of the one or more non-FTM-enabled APs in response to the non-FTM message; and (iii) calculating a non-FTM-based RTT measurement of the one or more non-FTM-based RTT measurements based on a difference between a time of arrival of the non-FTM response messages and a time of departure of the non-FTM message. The wireless station may then calculate a position of the wireless device based on both the one or more FTM-based RTT measurements and the one or more non-FTM-based RTT measurements.
[0011] In another aspect, a wireless station includes a transceiver, at least one processor; and at least one memory coupled to the at least one processor. The at least one processor and the at least one memory are configured to direct the wireless station to perform a fine timing measurement (FTM) procedure with each of one or more FTM- enabled access points (APs) to obtain a respective one or more FTM-based round-trip time (RTT) measurement between the wireless station and each of the one or more FTM-enabled APs. The FTM procedure may include: (i) exchanging at least one FTM message with an FTM-enabled AP of the one or more FTM-enabled APs; and (ii) calculating an FTM-based RTT measurement of the one or more FTM-based RTT measurements based on the exchanging of the at least one FTM message. The at least one processor and the at least one memory are also configured to direct the wireless station to perform a non-FTM procedure with each of one or more non-FTM-enabled APs to obtain a respective one or more non-FTM-based RTT measurements, where the non-FTM procedure includes: (i) transmitting a non-FTM message from the first wireless station to a non-FTM-enabled AP of the one or more non-FTM-enabled APs; (ii) receiving a non-FTM response message from the non-FTM-enabled AP of the one or more non-FTM-enabled APs in response to the non-FTM message; and (iii) calculating a non-FTM-based RTT measurement of the one or more non-FTM-based RTT measurements based on a difference between a time of arrival of the non-FTM response messages and a time of departure of the non-FTM message. The at least one processor and the at least one memory may then direct the wireless station to calculate a position of the wireless device based on both the one or more FTM-based RTT measurements and the one or more non-FTM-based RTT measurements.
[0012] In yet another aspect, a wireless station includes means for performing a fine timing measurement (FTM) procedure with each of one or more FTM-enabled access points (APs) to obtain a respective one or more FTM-based round-trip time (RTT) measurement between the wireless station and each of the one or more FTM-enabled APs. The means for performing the FTM procedure may include: (i) means for exchanging at least one FTM message with an FTM-enabled AP of the one or more FTM-enabled APs; and (ii) means for calculating an FTM-based RTT measurement of the one or more FTM-based RTT measurements based on the exchanging of the at least one FTM message. The wireless station also includes means for performing a non-FTM procedure with each of one or more non-FTM-enabled APs to obtain a respective one or more non-FTM-based RTT measurements, where the means for performing the non- FTM procedure includes: (i) means for transmitting a non-FTM message from the first wireless station to a non-FTM-enabled AP of the one or more non-FTM-enabled APs;
[0013] In another aspect, a non-transitory computer-readable medium includes program code stored thereon. The program code includes instructions to direct a wireless station to perform a fine timing measurement (FTM) procedure with each of one or more FTM-enabled access points (APs) to obtain a respective one or more FTM- based round-trip time (RTT) measurement between the wireless station and each of the one or more FTM-enabled APs. The FTM procedure may include: (i) exchanging at least one FTM message with an FTM-enabled AP of the one or more FTM-enabled APs; and (ii) calculating an FTM-based RTT measurement of the one or more FTM- based RTT measurements based on the exchanging of the at least one FTM message. The program code also includes instructions to direct the wireless station to perform a non-FTM procedure with each of the one or more non-FTM-enabled APs to obtain a respective one or more non-FTM-based RTT measurements, where the non-FTM procedure includes: (i) transmitting a non-FTM message from the first wireless station to a non-FTM-enabled AP of the one or more non-FTM-enabled APs; (ii) receiving a non-FTM response message from the non-FTM-enabled AP of the one or more non- FTM-enabled APs in response to the non-FTM message; and (iii) calculating a non- FTM-based RTT measurement of the one or more non-FTM-based RTT measurements based on a difference between a time of arrival of the non-FTM response messages and a time of departure of the non-FTM message. The program code may further include instructions to direct the wireless station to calculate a position of the wireless device based on both the one or more FTM-based RTT measurements and the one or more non-FTM-based RTT measurements.
[0015] FIG. 1 illustrates an example wireless network employing a Wi-Fi protocol.
[0016] FIG. 2 is a flowchart illustrating a process of determining a position of a wireless station using both a fine timing measurement (FTM) procedure and a non-FTM procedure.
[0017] FIG. 3 is a call flow procedure illustrating a process of determining a position of a wireless station using both an FTM procedure and a non-FTM procedure.
[0018] FIG. 4A is a flowchart illustrating a process for the joint calculation of a position of the wireless station and a turnaround calibration factor (TCF) of non-FTM- enabled access points (APs).
[0019] FIG. 4B is a flowchart illustrating a process for the joint calculation of a position of the wireless station, a position of non-FTM-enabled APs, and a turnaround calibration factor (TCF) of the non-FTM-enabled APs.
[0020] FIG. 4C is a flowchart illustrating a process for the calculation of a turnaround calibration factor (TCF) of non-FTM-enabled APs.
[0021] FIG. 5 is a simplified block diagram of several sample aspects of components that may be employed in an apparatus and configured to support communication as taught herein.
[0022] FIG. 6 is a simplified block diagram of several sample aspects of apparatuses configured to support communication as taught herein.
[0023] More specific aspects of the disclosure are provided in the following description and related drawings directed to various examples provided for illustration purposes. Altemate aspects may be devised without departing from the scope of the disclosure. Additionally, well-known aspects of the disclosure may not be described in detail or may be omitted so as not to obscure more relevant details.
[0024] Those of skill in the art will appreciate that the information and signals described below may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description below may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof, depending in part on the particular application, in part on the desired design, in part on the corresponding technology, etc.
[0025] Further, many aspects are described in terms of sequences of actions to be performed by, for example, elements of a computing device. It will be recognized that various actions described herein can be performed by specific circuits (e.g., Application Specific Integrated Circuits (ASICs)), by program instructions being executed by one or more processors, or by a combination of both. In addition, for each of the aspects described herein, the corresponding form of any such aspect may be implemented as, for example, "logic configured to" perform the described action.
[0026] FIG. 1 illustrates an example wireless network 100. As shown, the wireless network 100, which may also be referred to herein as a Basic Service Set (BSS), is formed from several wireless nodes, including one or more Access Points (APs) 11 OA, 110B, 112A, and 112B and at least one wireless station (STA) 120. Each wireless node is generally capable of receiving and/or transmitting. The wireless network 100 may support any number of APs 110A, HOB, 112A, and 112B distributed throughout a geographic region to provide coverage for the STA 120. For simplicity, only four APs 11 OA, HOB, 112A, and 112B are shown in FIG. 1, providing coordination and control among the STA 120 and other STAs (not shown), as well as access to other APs, server 140, or a network 150 (e.g., the Internet) via a backhaul connection 130. However, in other examples, the wireless network 100 may include many (more than four) APs, including several APs operating on the same WLAN channel and several other APs operating on different WLAN channels.
[0027] The APs 11 OA, HOB, 112A, and 112B are generally fixed entities that provide backhaul services to the STA 120 in their geographic region of coverage. However, the APs 110A, HOB, 112A, and 112B may be mobile in some applications (e.g., a mobile device serving as a wireless hotspot for other devices). The STA 120 may be fixed or mobile. Examples of STA 120 include a telephone (e.g., cellular telephone), a laptop computer, a desktop computer, a personal digital assistant (PDA), a digital audio player (e.g., MP3 player), a camera, a game console, a display device, or any other suitable wireless node. The wireless network 100 may be referred to as a wireless local area network (WLAN), and may employ a variety of widely used networking protocols to interconnect nearby devices. In general, these networking protocols may be referred to as "Wi-Fi," including any member of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 wireless protocol family.
[0028] In one example, 802.1 lmc is one protocol that provides access points with ability to perform fine timing measurements (FTM) with STA 120. As 802.1 lmc APs start to deploy, there will be venues with a mix of APs (i.e., some APs within a venue will be FTM-enabled APs, while other APs within the venue will be legacy APs that are non-FTM-enabled APs). Using the non-FTM-enabled APs for position determinations will require the use of a non-FTM procedure, such as the RTS/CTS-based method. However, as mentioned above, the RTS/CTS-based RTT method requires knowledge of the APs TCF (i.e., the APs turn-around calibration factor).
[0029] For example, the STA 120 of FIG. 1 may be configured to perform ranging operations using a fine timing measurement (FTM) procedure and/or via a non-FTM procedure. APs 110A and 1 10B are FTM-enabled APs such that STA 120 may perform the FTM procedure with the APs 11 OA and H OB for RTT measurements. However, APs 1 12A and 1 12B may be non-FTM-enabled APs, such that STA 120 is not able to perform the FTM procedure with the APs 112A and 112B. Instead, the STA 120 may be required to perform a non-FTM procedure, such as the RTS/CTS-based RTT method to perform RTT measurements with APs 112A and 1 12B. In one example, APs 112A and 1 12B are legacy devices that do not include the capability to perform RTT measurements using an FTM procedure. In another example, APs 1 12A and 112B have the capability to perform FTM procedures, but that feature is disabled or otherwise incapacitated. As mentioned above, the RTS/CTS-based RTT procedure requires knowledge of one or more delays, such as the turnaround calibration factor (TCF) at the APs 1 12A and 1 12B.
[0030] Accordingly, STA 120 may be variously configured in accordance with the teachings herein to provide or otherwise support the position determination of STA 120 based on both an FTM procedure performed with one or more of the APs 11 OA and HOB and on a non-FTM procedure performed with one or more of the APs 112A and 1 12B in wireless network 100. Thus, as shown in FIG. 1 , the STA 120 may include a position determination block 122 for determining the position of the STA 120 based on both the FTM procedure and the non-FTM procedure. These and other aspects will be described in more detail below.
[0031] FIG. 2 is a flowchart illustrating a process 200 of determining a position of a wireless station using both an FTM procedure and a non-FTM procedure (e.g., STA 120 under direction of position determination block 122).
[0032] In process block 210, STA 120 performs an FTM procedure with each of one or more FTM-enabled APs 11 OA and HOB to obtain a respective one or more FTM- based round-trip time (RTT) measurements between the STA 120 and the APs 1 10A and H OB. In one aspect, the FTM procedure includes exchanging one or more FTM messages between the STA 120 and the AP 11 OA to obtain the first FTM-based RTT measurement. Similarly, STA 120 and AP HOB may exchange one or more FTM messages to obtain a second FTM-based RTT measurement. For example, the exchanging of FTM messages may include the STA 120 transmitting an FTM request message to the AP 11 OA, receiving an FTM response message from the AP 1 1 OA, transmitting an FTM acknowledgement message to the AP 11 OA, and then receiving timing information from the AP 11 OA. The timing information may indicate a time of departure of the FTM response message from the AP 11 OA, as well as a time of arrival of the FTM acknowledgement message at the AP 1 1 OA. In one example, the timing information is sent as timestamps from the AP 110A to the STA 120. The STA 120 may then compute the first FTM-based RTT measurement using the timing information received from the AP 1 10A as well as timing information (e.g., timestamps) generated at the STA 120, itself. Further details regarding the FTM procedure will be described below with reference to FIG. 3.
[0033] Next, in process block 220, the STA 120 performs a non-FTM procedure with each of one or more non-FTM-enabled APs 112A and 112B to obtain a respective one or more non-FTM-based RTT measurements between the STA 120 and the APs 1 12A and 1 12B. In one example, the non-FTM procedure includes transmitting a non- FTM message from the STA 120 to the AP 1 12A, receiving a non-FTM response message from the AP 1 12A in response to the non-FTM message, and calculating a non-FTM-based RTT measurement based on a difference between a time of arrival of the non-FTM response message and a time of departure of the non-FTM message. By way of example, the non-FTM message may be a request-to-send (RTS) message and the non-FTM response message may be a clear-to-send (CTS) message. Thus, in one implementation, the STA 120 is configured to generate a timestamp corresponding to the time of departure when the RTS message is transmitted and to generate another timestamp corresponding to the time of arrival when the CTS message is received at the STA 120. The STA 120 may calculate the non-FTM-based RTT measurement by subtracting the time of departure of the RTS message from the time of arrival of the CTS message.
[0034] In one example, the STA 120 calculates the second RTT without compensating for any delays that may be imposed by the APs 112A and 112B in the processing of the non-FTM messages. Thus, any delays between when the APs 1 12A and 112B receive the non-FTM message and when the APs 1 12A and 112B transmit their non-FTM response messages are included in the non-FTM-based RTT measurements, such that the non-FTM-based RTT measurements may be referred to as uncompensated RTT measurements.
[0035] Next, in process block 230, the STA 120 calculates a position of the STA 120 based on both the one of more FTM-based RTT measurements and the one or more non-FTM-based RTT measurements. In one example, the STA 120 calculates the position of the STA 120 using both the FTM-based RTT measurements and the non- FTM-based RTT measurements directly, without an intervening determination of the position of the STA 120. That is, rather than combining a position determination based on the FTM-based RTT measurements with a position determination based on the non- FTM-based RTT measurements, aspects of the present disclosure may include the STA 120 performing a single position determination using both the FTM-based and non- FTM-based RTT measurements.
[0036] Although FIG. 2 illustrates process 200 as performing the FTM procedure and then the non-FTM procedure, other examples may include performing the procedures in a reverse order, or even simultaneously. That is, STA 120 may perform the non-FTM procedure first and then perform the FTM procedure in accordance with the teachings herein, or the STA 120 may perform at least some of the non-FTM procedures with some of the non-FTM-enabled APs during the same time period that the STA 120 performs at least some of the FTM procedures with the FTM-enabled APs.
[0037] FIG. 3 is a call flow procedure illustrating process 300 of determining a position of a wireless station (e.g., STA 120) using both an FTM and a non-FTM procedure. Process 300 is one possible implementation of process 200 of FIG. 2.
[0038] As shown in FIG. 3, process 300 includes an optional step of a STA 306 receiving position assistance data 307 from a server 302 (e.g., corresponding to server 140 of FIG. 1). In one example, the position assistance data 307 includes a position of one or more non-FTM-enabled APs 304 and/or the position of one or more FTM- enabled APs 305.
[0039] FIG. 3 further illustrates an FTM procedure 301 that includes exchanging FTM messages 308-314 between STA 306 and FTM-enabled APs 305. In particular, at time Tl, STA 306 transmits an FTM request message 308, which is received at an FTM-enabled AP of the FTM-enabled APs 305 at time T2. In response to the FTM request message 308, the FTM-enabled AP 305 transmits an FTM response message 310 at time T3. The FTM response message 310 is received at the STA 306 at time T4. The STA 306 then transmits an acknowledgement message 312 at time T5. Furthermore, the STA 306 may generate a first timestamp corresponding to time T4 and a second timestamp corresponding to time T5. At time T6, the FTM-enabled AP 305 receives the acknowledgement message 312 and in response thereto, generates a timing information message 314 which is sent back to the STA 306 at time T7. The timing information message 314 includes the time of departure of the FTM response message 310 (i.e., time T3) as well as the time of arrival of the acknowledgement message 312 (i.e., time T6). In one example, the time of departure corresponding to time T3 and the time of arrival corresponding to time T6 are included in the timing information message 314 as timestamps generated by the FTM-enabled AP 305. Upon receipt of the timing information message 314 at time T8, the STA 306 may then calculate a first FTM-based RTT measurement. In one aspect, the first FTM-based RTT measurement is calculated based on the times T3, T4, T5, and T6. For example, STA 306 may calculate the first FTM-based RTT measurement as (T6 - T3) - (T5 - T4).
[0040] Next, STA 306 may perform a non-FTM procedure 303 that includes exchanging non-FTM messages 316 and 318 between the STA 306 and one or more non-FTM-enabled APs 304. At time T9, the STA 306 transmits a non-FTM message 316 to a non-FTM-enabled AP of the non-FTM-enabled APs 304. In one example, the non-FTM message 316 is a request-to-send (RTS) message, but could alternatively be a data message. Also, at time T9, STA 306 generates a timestamp corresponding to a time of departure of the non-FTM message 316 (i.e., time T9). The non-FTM message 316 is received at the non-FTM-enabled AP 304 at time T10, which then transmits a non-FTM response message 318 to the STA 306 at time Ti l . In one aspect, the non- FTM response message 318 is a clear-to-send (CTS) message, but alternatively could be an acknowledgement message.
[0041] The STA 306 then receives the non-FTM response message 318 at time T12 and generates a timestamp corresponding to a time of arrival of the non-FTM response message 318 (i.e., time T12). The STA 306 may then calculate the non-FTM-based RTT measurement based on the times T9 and T12 (e.g., T12 - T9). As shown in FIG. 3, the non-FTM-enabled APs 304 may encounter one or more delays between the receipt of the non-FTM message 316 at time T10 and the transmitting of the non-FTM response message 318 at time Ti l . Thus, the non-FTM-based RTT measurement calculated by the STA 306 is an uncompensated RTT measurement that includes one or more delays incurred at the non-FTM-enabled APs 304 (e.g., delay = Tl 1 - T10).
[0042] As will be discussed below, the STA 306 may calculate a TCF estimate of the non-FTM-enabled APs 304 in addition to calculating a position of the STA 306. In one example, the TCF estimate is an estimate of the delay encountered at the non-FTM- enabled APs 304 from time T10 to time Ti l.
[0043] After the STA 306 has calculated the TCF estimate of the non-FTM-enabled APs 304, the STA 306 may send TCF estimates to server 302. The message 320 may include a single TCF estimate for each of the non-FTM-enabled APs 304 calculated by the STA 306 or it may include an average of multiple TCF estimates calculated by the STA 306 corresponding to FTM and non-FTM procedures performed with the non- FTM-enabled APs 304. In one example, the server 302 may store one or more of the TCF estimates received by way of message 320. The server 302 may then provide the TCF estimates to other wireless stations that may not be FTM-enabled. In another example, the STA 306 may store the one or more TCF estimates locally at the STA 306, itself. The locally stored TCF estimates may then be utilized by the STA 306 in future position determinations where there are an insufficient number of FTM-enabled APs to determine a position of the STA 306.
[0044] In some examples, STA 120/306 is configured to calculate various parameters (e.g., STA 120/306 position, non-FTM-enabled AP position, FTM-enabled AP position, TCF estimates, etc.) related to position determinations depending on the amount of information and/or the number of FTM-enabled and non-FTM enabled APs available to the STA 120/306. A number of example use cases are described below with reference to FIGS. 4A-4C.
[0045] FIG. 4A is a flowchart illustrating a process 400a for the joint calculation of a position of the wireless station (e.g., STA 120/306) and a turnaround calibration factor (TCF) of non-FTM-enabled access points (APs). In process block 410, the wireless station obtains the position of one or more of the non-FTM-enabled APs 304 and a position of the one or more FTM-enabled APs 305. As mentioned above, the wireless station may obtain the position of the non-FTM-enabled APs and/or FTM-enabled APs by way of the position assistance data 307 received from server 302.
[0046] In process block 420, the wireless station determines whether a number of available FTM-enabled APs is greater than a first threshold. That is, the first threshold relates to a number of FTM-enabled APs that would allow the wireless station to jointly calculate the position of the wireless device and a TCF for at least one of the non-FTM- enabled APs 304. If the number of FTM-enabled APs is greater than the first threshold, then process block 430 includes the wireless device performing the joint calculation of the position of the wireless device and the TCF for one or more of the non-FTM enabled APs 304. In one example, the joint calculation of the position of the wireless device and the TCF includes calculating both the position of the wireless device and the TCF, without an intervening determination of the position of the wireless device. That is, rather than first determining a position of the wireless device and then determining a TCF of the non-FTM-enabled APs, aspects of the present disclosure may include the wireless performing a single procedure that determines both the position of the wireless device and the TCF of the non-FTM-enabled APs.
[0047] FIG. 4B is a flowchart illustrating a process 400b for the joint calculation of a position of the wireless station, a position of non-FTM-enabled APs, and a turnaround calibration factor (TCF) of the non-FTM-enabled APs. In process 400b, the position of one or more of the non-FTM-enabled APs is unknown to the wireless station. Thus, in process block 440, the wireless station determines whether a number of available FTM- enabled APs is greater than a second threshold. That is, the second threshold relates to a number of FTM-enabled APs that would allow the wireless station to jointly calculate the position of the wireless device, a position of one or more of the non-FTM-enabled APs 304, and a TCF for at least one of the non-FTM-enabled APs 304. In one example, the second threshold is variable and relates to the number of unknowns to be determined by the wireless station. That is, the more TCF estimates that are unknown and/or the more non-FTM-enabled AP positions that are to be determined, means that a greater number of FTM-enabled APs are needed for the joint calculation of wireless station position, non-FTM-enabled AP positions, and TCF estimates of the non-FTM-enabled APs. In one aspect, the second threshold is met if the number of available FTM-enabled APs exceeds the number of unknowns, which include the number of TCF estimates and non-FTM-enabled AP positions that are to be determined.
[0048] If the number of FTM-enabled APs is greater than the second threshold, then process block 450 includes the wireless device performing the joint calculation of the position of the wireless device, a position of one or more of the non-FTM-enabled APs 304, and the TCF for the one or more non-FTM enabled APs 304. In one example, the joint calculation of the position of the wireless device, the position of the non-FTM enabled APs 304, and the TCF includes calculating the position of the wireless device, the position of the non-FTM-enabled APs 304, and the TCF, without an intervening determination of the position of the wireless device. That is, rather than first determining a position of the wireless device and then determining the position of the non-FTM-enabled AP 304 and/or a TCF of the non-FTM-enabled APs, aspects of the present disclosure may include the wireless performing a single procedure that determines the position of the wireless device, the position of the non-FTM-enabled APs, and the TCF of the non-FTM-enabled APs.
[0049] FIG. 4C is a flowchart illustrating a process 400c for the calculation of a turnaround calibration factor (TCF) of non-FTM-enabled APs. In process 400c, the position of one or more of the non-FTM-enabled APs is known to the wireless station. Thus, in process block 460, the wireless station determines whether a number of available FTM-enabled APs is greater than a third threshold. That is, the third threshold relates to a number of FTM-enabled APs that would allow the wireless station to calculate the position of the wireless device, and then subsequently calculate a TCF for one or more of the non-FTM-enabled APs whose position is known to the wireless station.
[0050] If the number of FTM-enabled APs is greater than the third threshold, then process block 470 includes the wireless device performing the calculation of the position of the wireless device. In one example, the calculation of the position of the wireless device is determined by the wireless station based on the FTM-based RTT measurements obtained by way of the FTM procedure 301 performed with the FTM- enabled APs 305. Next, in process block 470, the wireless device calculates a TCF of at least one of the non-FTM-enabled APs 304 based on the calculated position of the wireless device (i.e., process block 470) and based on both the FTM-based RTT measurements (i.e., via FTM procedure 301) and the non-FTM-based RTT measurements (i.e., via non-FTM procedure 303).
[0051] FIG. 5 illustrates several sample components (represented by corresponding blocks) that may be incorporated into an apparatus 502, an apparatus 504, and an apparatus 506 (corresponding to, for example, a wireless station (STA), a base station, and a server, respectively) to support the position determination of a wireless station, as taught herein. It will be appreciated that these components may be implemented in different types of apparatuses in different implementations (e.g., in an ASIC, in an SoC, etc.). The illustrated components may also be incorporated into other apparatuses in a communication system. For example, other apparatuses in a system may include components similar to those described to provide similar functionality. Also, a given apparatus may contain one or more of components. For example, an apparatus may include multiple transceiver components that enable the apparatus to operate on multiple carriers and/or communicate via different technologies.
[0052] The apparatus 502 and the apparatus 504 each include at least one wireless communication device (represented by communication devices 508 and 514 (and communication device 520 if the apparatus 504 is a relay)) for communicating with other nodes via at least one designated radio access technology (RAT). Each communication device 508 includes at least one transmitter (represented by transmitter 510) for transmitting and encoding signals (e.g., messages, indications, information, and so on) and at least one receiver (represented by receiver 512) for receiving and decoding signals (e.g., messages, indications, information, pilots, and so on). Similarly, each communication device 514 includes at least one transmitter (represented by transmitter 516) for transmitting signals (e.g., messages, indications, information, pilots, and so on) and at least one receiver (represented by receiver 518) for receiving signals (e.g., messages, indications, information, and so on). If the apparatus 504 is a relay station, each communication device 520 may include at least one transmitter (represented by transmitter 522) for transmitting signals (e.g., messages, indications, information, pilots, and so on) and at least one receiver (represented by receiver 524) for receiving signals (e.g., messages, indications, information, and so on).
[0053] A transmitter and a receiver may comprise an integrated device (e.g., embodied as a transmitter circuit and a receiver circuit of a single communication device) in some implementations, may comprise a separate transmitter device and a separate receiver device in some implementations, or may be embodied in other ways in other implementations. A wireless communication device (e.g., one of multiple wireless communication devices) of the apparatus 504 may also comprise a Network Listen Module (NLM) or the like for performing various measurements.
[0054] The apparatus 506 (and the apparatus 504 if it is not a relay station) includes at least one communication device (represented by communication device 526 and, optionally, communication device 520) for communicating with other nodes. For example, the communication device 526 may comprise a network interface that is configured to communicate with one or more network entities via a wire-based or wireless backhaul. In some aspects, the communication device 526 may be implemented as a transceiver configured to support wire-based or wireless signal communication. This communication may involve, for example, sending and receiving: messages, parameters, or other types of information. Accordingly, in the example of FIG. 5, the communication device 526 is shown as comprising a transmitter 528 and a receiver 530. Similarly, if the apparatus 504 is not a relay station, the communication device 520 may comprise a network interface that is configured to communicate with one or more network entities via a wire-based or wireless backhaul. As with the communication device 526, the communication device 520 is shown as comprising a transmitter 522 and a receiver 524.
[0055] The apparatuses 502, 504, and 506 also include other components that may be used in conjunction with the position determination of a wireless station as taught herein. The apparatus 502 includes a processing system 532 for providing functionality relating to, for example, the performing of an FTM procedure, the performing of a non- FTM procedure, and the calculating a position of the wireless station, as taught herein, and for providing other processing functionality. The apparatus 504 includes a processing system 534 for providing functionality relating to, for example, exchanging FTM and/or non-FTM messages, as taught herein, and for providing other processing functionality. The apparatus 506 includes a processing system 536 for providing functionality relating to, for example, providing position assistance data, and for providing other processing functionality. The apparatuses 502, 504, and 506 include memory components 538, 540, and 542 (e.g., each including a memory device), respectively, for maintaining information (e.g., information indicative of reserved resources, thresholds, parameters, and so on). In addition, the apparatuses 502, 504, and 506 include user interface devices 544, 546, and 548, respectively, for providing indications (e.g., audible and/or visual indications) to a user and/or for receiving user input (e.g., upon user actuation of a sensing device such a keypad, a touch screen, a microphone, and so on).
[0056] For convenience, the apparatuses 502, 504, and/or 506 are shown in FIG. 5 as including various components that may be configured according to the various examples described herein. It will be appreciated, however, that the illustrated blocks may have different functionality in different designs.
[0057] The components of FIG. 5 may be implemented in various ways. In some implementations, the components of FIG. 5 may be implemented in one or more circuits such as, for example, one or more processors and/or one or more ASICs (which may include one or more processors). Here, each circuit may use and/or incorporate at least one memory component for storing information or executable code used by the circuit to provide this functionality. For example, some or all of the functionality represented by blocks 508, 532, 538, and 544 may be implemented by processor and memory component(s) of the apparatus 502 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Similarly, some or all of the functionality represented by blocks 514, 520, 534, 540, and 546 may be implemented by processor and memory component(s) of the apparatus 504 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components). Also, some or all of the functionality represented by blocks 526, 536, 542, and 548 may be implemented by processor and memory component(s) of the apparatus 506 (e.g., by execution of appropriate code and/or by appropriate configuration of processor components).
[0058] FIG. 6 illustrates an example wireless station (STA) 600 represented as a series of interrelated functional modules. STA 600 is one possible implementation of STA 120 and/or apparatus 502. A module 602 for performing an FTM procedure with each of one or more FTM-enabled APs to obtain a respective one or more FTM-based RTT measurements may correspond at least in some aspects to, for example, a communication device 508, as discussed herein. A module 604 for performing a non- FTM procedure with each of one or more non-FTM-enabled APs to obtain a respective one or more non-FTM-based RTT measurements may correspond at least in some aspects to, for example, a communication device 508, as discussed herein. A module 606 for calculating a position of the wireless station based on both the one or more FTM-based RTT measurements and the one or more non-FTM-based RTT measurements may correspond, at least in some aspects to, for example, processing system 532 and/or memory component 538.
[0059] The functionality of the modules of FIG. 6 may be implemented in various ways consistent with the teachings herein. In some designs, the functionality of these modules may be implemented as one or more electrical components. In some designs, the functionality of these modules may be implemented as a processing system including one or more processor components. In some designs, the functionality of these modules may be implemented using, for example, at least a portion of one or more integrated circuits (e.g., an ASIC). As discussed herein, an integrated circuit may include a processor, software, other related components, or some combination thereof. Thus, the functionality of different modules may be implemented, for example, as different subsets of an integrated circuit, as different subsets of a set of software modules, or a combination thereof. Also, it will be appreciated that a given subset (e.g., of an integrated circuit and/or of a set of software modules) may provide at least a portion of the functionality for more than one module.
[0060] In addition, the components and functions represented by FIG. 6, as well as other components and functions described herein, may be implemented using any suitable means. Such means also may be implemented, at least in part, using corresponding structure as taught herein. For example, the components described above in conjunction with the "module for" components of FIG. 6 also may correspond to similarly designated "means for" functionality. Thus, in some aspects one or more of such means may be implemented using one or more of processor components, integrated circuits, or other suitable structure as taught herein.
[0061] It should be understood that any reference to an element herein using a designation such as "first," "second," and so forth does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements may be employed there or that the first element must precede the second element in some manner. Also, unless stated otherwise a set of elements may comprise one or more elements. In addition, terminology of the form "at least one of A, B, or C" or "one or more of A, B, or C" or "at least one of the group consisting of A, B, and C" used in the description or the claims means "A or B or C or any combination of these elements." For example, this terminology may include A, or B, or C, or A and B, or A and C, or A and B and C, or 2A, or 2B, or 2C, and so on.
[0062] In view of the descriptions and explanations above, those of skill in the art will appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the aspects disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present disclosure.
[0063] Accordingly, it will be appreciated, for example, that an apparatus or any component of an apparatus may be configured to (or made operable to or adapted to) provide functionality as taught herein. This may be achieved, for example: by manufacturing (e.g., fabricating) the apparatus or component so that it will provide the functionality; by programming the apparatus or component so that it will provide the functionality; or through the use of some other suitable implementation technique. As one example, an integrated circuit may be fabricated to provide the requisite functionality. As another example, an integrated circuit may be fabricated to support the requisite functionality and then configured (e.g., via programming) to provide the requisite functionality. As yet another example, a processor circuit may execute code to provide the requisite functionality.
[0064] Moreover, the methods, sequences, and/or algorithms described in connection with the aspects disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor (e.g., cache memory).
[0065] Accordingly, it will also be appreciated, for example, that certain aspects of the disclosure can include a computer-readable medium embodying a method as discussed above with reference to FIGS. 2-4C.
[0066] While the foregoing disclosure shows various illustrative aspects, it should be noted that various changes and modifications may be made to the illustrated examples without departing from the scope defined by the appended claims. The present disclosure is not intended to be limited to the specifically illustrated examples alone. For example, unless otherwise noted, the functions, steps, and/or actions of the method claims in accordance with the aspects of the disclosure described herein need not be performed in any particular order. Furthermore, although certain aspects may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.

中文:
[0001]本发明的各方面大体上涉及无线通信,且更具体地说,涉及无线局域网(WLAN)接入点(AP)定位和导航系统。
[0002]无线通信系统经广泛部署以提供各种类型的通信内容,例如,语音、数据等等。典型的无线通信系统是多址接入系统,所述多址接入系统能够通过共享可供使用的系统资源(例如,带宽、发射功率等)来支持与多个用户的通信。一类这种多址接入系统一般被称为无线局域网(WLAN),例如,“Wi-Fi”,并且包含电气电子工程师学会(IEEE)802.11无线协议族的不同构成部分。通常,Wi-Fi通信系统可以同时支持多个无线装置(例如,无线站(STA))的通信。每个STA经由下行链路和上行链路上的传输与一或多个接入点(AP)通信。下行链路(DL)是指从AP到STA的通信链路,并且上行链路(UL)是指从STA到AP的通信链路。
[0003]现代的导航系统通常使用基于卫星的全球定位系统(GPS)用于位置确定。然而,近来WLAN(例如,Wi-Fi)接入点的增加已使得导航系统使用这些接入点来进行位置确定成为可能,尤其是在通常集中存在大量WLAN接入点的城市区域中。由于GPS信号覆盖范围的局限性,WLAN导航系统可以比GPS导航系统更有利。举例来说,虽然GPS信号在购物中心内可能并不是容易地可供使用的,但是在购物中心内通过WLAN接入点产生的无线信号会更容易被STA检测到。
[0004]更确切地说,对于WLAN导航系统,WLAN接入点的位置被用作参考点,从所述参考点众所周知的三边测量技术可以确定无线装置(例如,启用Wi-Fi的手机、膝上型计算机或平板计算机)的位置(例如,绝对位置和/或相对位置)。无线装置可以使用发射到接入点和从接入点发射的信号的往返时间(RTT)来计算无线装置与接入点之间的距离。一旦计算出这些距离,就可以使用三边测量技术来估计无线装置的位置。
[0005]用于确定RTT的一个过程俘获通过STA到AP的单播包(例如,数据包或请求发送(RTS))的发射与适当的响应包(其可以是确认(ACK)或清除发送(CTS))的接收之间的时间量,如通过STA所测量。RTT通常是以纳秒测量的。
[0006]一些芯片设计可允许使用时间戳的从STA的出发时间(TOD)以及在STA处的到达时间(TOA)的记录。时间戳准许RTT的测量。此方法可被称为基于RTS/CTS的RTT过程(在本文中也被称为非精细定时测量(FTM)过程)。
[0007]然而,在测量RTT中存在在AP或接收节点处涉及的可变数量的周转时间延迟,在RTT可以用于测距计算之前需要考量所述周转时间延迟。使用RTT的这些测距计算是通过提取STA与AP之间的飞行时间进行的,这需要了解周转校准因数(TCF)。TCF可以是实施方案特定的并且可以取决于短帧间间隔(SIFS)、到达时间不确定性和在AP处的其它延迟。TCF取决于供AP使用的芯片组而变化。
[0008]用于确定节点之间的距离的另一方法通常被称为精细定时测量(FTM)协议。基于FTM,STA与AP交换FTM消息,并且随后从AP接收定时信息(例如,对应于在AP处的FTM消息的到达和出发时间的时间戳)。STA随后基于定时信息计算其到AP的距离。
[0009]本发明的方面包含用于基于基于精细定时测量(FTM)的往返时间(RTT)测量值和非基于FTM的RTT测量值两者辅助或者执行位置确定的方法、无线站和计算机可读媒体。
[0010]举例来说,在一个方面中,一种方法包含通过无线站用一或多个启用精细定时测量(FTM)的接入点(AP)中的每一个执行FTM过程以获得在无线站与一或多个启用FTM的AP中的每一个之间的相应的一或多个基于FTM的往返时间(RTT)测量值。FTM过程可以包含:(i)与一或多个启用FTM的AP的启用FTM的AP交换至少一个FTM消息;以及(ii)基于至少一个FTM消息的交换计算一或多个基于FTM的RTT测量值的基于FTM的RTT测量值。所述方法还包含用一或多个非启用FTM的AP中的每一个执行非FTM过程以获得相应的一或多个非基于FTM的RTT测量值,其中非FTM过程包含:(i)将非FTM消息从第一无线站发射到一或多个非启用FTM的AP的非启用FTM的AP;(ii)响应于非FTM消息从一或多个非启用FTM的AP的非启用FTM的AP接收非FTM响应消息;以及(iii)基于非FTM响应消息的到达时间与非FTM消息的出发时间之间的差异计算一或多个非基于FTM的RTT测量值的非基于FTM的RTT测量值。无线站可随后基于一或多个基于FTM的RTT测量值和一或多个非基于FTM的RTT测量值两者计算无线装置的位置。
[0011]在另一方面中,无线站包含收发器、至少一个处理器;以及耦合到所述至少一个处理器的至少一个存储器。至少一个处理器和至少一个存储器经配置以引导无线站用一或多个启用精细定时测量(FTM)的接入点(AP)中的每一个执行FTM过程以获得在无线站与一或多个启用FTM的AP中的每一个之间的相应的一或多个基于FTM的往返时间(RTT)测量值。FTM过程可以包含:(i)与一或多个启用FTM的AP的启用FTM的AP交换至少一个FTM消息;以及(ii)基于至少一个FTM消息的交换计算一或多个基于FTM的RTT测量值的基于FTM的RTT测量值。至少一个处理器和至少一个存储器还经配置以引导无线站用一或多个非启用FTM的AP中的每一个执行非FTM过程以获得相应的一或多个非基于FTM的RTT测量值,其中非FTM过程包含:(i)将非FTM消息从第一无线站发射到一或多个非启用FTM的AP的非启用FTM的AP;(ii)响应于非FTM消息从一或多个非启用FTM的AP的非启用FTM的AP接收非FTM响应消息;以及(iii)基于非FTM响应消息的到达时间与非FTM消息的出发时间之间的差异计算一或多个非基于FTM的RTT测量值的非基于FTM的RTT测量值。至少一个处理器和至少一个存储器可随后引导无线站基于一或多个基于FTM的RTT测量值和一或多个非基于FTM的RTT测量值两者计算无线装置的位置。
[0012]在又一方面中,无线站包含用于用一或多个启用精细定时测量(FTM)的接入点(AP)中的每一个执行FTM过程以获得在无线站与一或多个启用FTM的AP中的每一个之间的相应的一或多个基于FTM的往返时间(RTT)测量值的装置。用于执行FTM过程的装置可以包含:(i)用于与一或多个启用FTM的AP的启用FTM的AP交换至少一个FTM消息的装置;以及(ii)用于基于至少一个FTM消息的交换计算一或多个基于FTM的RTT测量值的基于FTM的RTT测量值的装置。无线站还包含用于用一或多个非启用FTM的AP中的每一个执行非FTM过程以获得相应的一或多个非基于FTM的RTT测量值的装置,其中用于执行非FTM过程的装置包含:(i)用于将非FTM消息从第一无线站发射到一或多个非启用FTM的AP的非启用FTM的AP的装置;(ii)用于响应于非FTM消息从一或多个非启用FTM的AP的非启用FTM的AP接收非FTM响应消息的装置;以及(iii)用于基于非FTM响应消息的到达时间与非FTM消息的出发时间之间的差异计算一或多个非基于FTM的RTT测量值的非基于FTM的RTT测量值的装置。无线站还包含用于基于一或多个基于FTM的RTT测量值和一或多个非基于FTM的RTT测量值两者计算无线装置的位置的装置。
[0013]在另一方面中,一种非暂时性计算机可读媒体包含存储于其上的程序代码。程序代码包含指令以引导无线站用一或多个启用精细定时测量(FTM)的接入点(AP)中的每一个执行FTM过程以获得在无线站与一或多个启用FTM的AP中的每一个之间的相应的一或多个基于FTM的往返时间(RTT)测量值。FTM过程可以包含:(i)与一或多个启用FTM的AP的启用FTM的AP交换至少一个FTM消息;以及(ii)基于至少一个FTM消息的交换计算一或多个基于FTM的RTT测量值的基于FTM的RTT测量值。程序代码还包含指令以引导无线站用一或多个非启用FTM的AP中的每一个执行非FTM过程以获得相应的一或多个非基于FTM的RTT测量值,其中非FTM过程包含:(i)将非FTM消息从第一无线站发射到一或多个非启用FTM的AP的非启用FTM的AP;(ii)响应于非FTM消息从一或多个非启用FTM的AP的非启用FTM的AP接收非FTM响应消息;以及(iii)基于非FTM响应消息的到达时间与非FTM消息的出发时间之间的差异计算一或多个非基于FTM的RTT测量值的非基于FTM的RTT测量值。程序代码可进一步包含指令以引导无线站基于一或多个基于FTM的RTT测量值和一或多个非基于FTM的RTT测量值两者计算无线装置的位置。
[0015]图1说明采用Wi-Fi协议的实例无线网络。
[0016]图2是说明使用精细定时测量(FTM)过程和非FTM过程两者确定无线站的位置的过程的流程图。
[0017]图3是说明使用FTM过程和非FTM过程两者确定无线站的位置的过程的调用流程。
[0018]图4A是说明用于无线站的位置和非启用FTM的接入点(AP)的周转校准因数(TCF)的联合计算的过程的流程图。
[0019]图4B是说明用于无线站的位置、非启用FTM的AP的位置和非启用FTM的AP的周转校准因数(TCF)的联合计算的过程的流程图。
[0020]图4C是说明用于非启用FTM的AP的周转校准因数(TCF)的计算的过程的流程图。
[0021]图5是如本文中所教示的可以在设备中采用且经配置以支持通信的组件的若干样本方面的简化的方块图。
[0022]图6是如本文中所教示的经配置以支持通信的设备的若干样本方面的简化的方块图。
[0023]在以下出于说明的目的提供的涉及各种实例的描述和相关图式中提供本发明的更具体方面。可在不脱离本发明的范围的情况下设计出替代性方面。另外,可能不详细地描述本发明的众所周知的方面或可将其省略以免混淆更多相关细节。
[0024]所属领域的技术人员将了解可以使用多种不同科技和技术中的任一者来表示下文描述的信息和信号。举例来说,可在以下整个描述中参考的数据、指令、命令、信息、信号、位、符号和芯片可部分地取决于特定应用、部分地取决于所期望的设计、部分地取决于对应的技术等由电压、电流、电磁波、磁场或磁粒子、光场或光学粒子或其任何组合表示。
[0025]另外,就将由(例如)计算装置的元件执行的动作的顺序而言描述许多方面。将认识到,本文中所描述的各种动作可由特定电路(例如,专用集成电路(ASIC)),由正由一或多个处理器执行的程序指令或由两者的组合来执行。另外,对于本文中所描述的方面中的每一个,任何此类方面的对应的形式可实施为例如“经配置以”执行所描述的动作的“逻辑”。
[0026]图1说明实例无线网络100。如图所示,在本文中也可以被称为基本服务集(BSS)的无线网络100是从若干无线节点形成的,包含一或多个接入点(AP)110A、110B、112A和112B以及至少一个无线站(STA)120。每个无线节点一般能够进行接收和/或发射。无线网络100可以支持分布在整个地理区中的任何数目的AP 110A、110B、112A和112B以提供对STA 120的覆盖。为了简单起见,在图1中仅示出了四个AP 110A、110B、112A和112B,提供STA 120和其它STA(未示出)之中的协作和控制,以及经由回程连接130接入其它AP、服务器140或网络150(例如,因特网)。然而,在其它实例中,无线网络100可以包含许多(超过四个)AP,包含在相同WLAN信道上操作的若干AP以及在不同WLAN信道上操作的若干其它AP。
[0027]AP 110A、110B、112A和112B一般是在STA 120的地理覆盖区中为其提供回程服务的固定实体。然而,在一些应用中(例如,移动装置充当其它装置的无线热点),AP 110A、110B、112A和112B可以是移动的。STA 120可以是固定的或移动的。STA 120的实例包含电话(例如,蜂窝电话)、膝上型计算机、桌上型计算机、个人数字助理(PDA)、数字音频播放器(例如,MP3播放器)、相机、游戏控制台、显示装置或任何其它合适的无线节点。无线网络100可以被称为无线局域网(WLAN),并且可以采用多种广泛使用的网络协议来互连附近装置。一般来说,这些网络协议可以被称为“Wi-Fi”,包含电气电子工程师学会(IEEE)802.11无线协议族的任何构成部分。
[0028]在一个实例中,802.11mc是向接入点提供通过STA 120执行精细定时测量(FTM)的能力的一个协议。随着802.11mc AP开始部署,将存在具有混合的AP的场所(即,场所内的一些AP将是启用FTM的AP,而场所内的其它AP将是非启用FTM的AP的传统AP)。使用非启用FTM的AP用于位置确定将需要使用非FTM过程,例如,基于RTS/CTS的方法。然而,如上文所提及,基于RTS/CTS的RTT方法需要AP TCF的知识(即,AP周转校准因数)。
[0029]举例来说,图1的STA 120可经配置以使用精细定时测量(FTM)过程和/或经由非FTM过程执行测距操作。AP 110A和110B是启用FTM的AP,使得STA 120可以通过AP 110A和110B执行FTM过程用于RTT测量。然而,AP 112A和112B可以是非启用FTM的AP,使得STA 120并不能够通过AP 112A和112B执行FTM过程。替代地,STA120可能需要执行非FTM过程(例如,基于RTS/CTS的RTT方法)以通过AP 112A和112B执行RTT测量。在一个实例中,AP 112A和112B是并不包含使用FTM过程执行RTT测量的能力的传统装置。在另一实例中,AP 112A和112B具有执行FTM过程的能力,但是该特征被停用或者丧失能力。如上文所提及,基于RTS/CTS的RTT过程需要一或多个延迟的知识,例如,在AP 112A和112B处的周转校准因数(TCF)。
[0030]相应地,STA 120可以根据本文中的教示不同地配置以基于在无线网络100中通过AP 110A和110B中的一或多个执行的FTM过程和通过AP 112A和112B中的一或多个执行的非FTM过程两者提供或者支持STA 120的位置确定。因此,如图1所示,STA 120可以包含用于基于FTM过程和非FTM过程两者确定STA 120的位置的位置确定块122。这些和其它方面将在下文更详细地描述。
[0031]图2是说明使用FTM过程和非FTM过程两者确定无线站的位置的过程200的流程图(例如,STA 120在位置确定块122的方向下方)。
[0032]在过程块210中,STA 120通过一或多个启用FTM的AP 110A和110B中的每一个执行FTM过程以获得在STA 120与AP 110A和110B之间的相应的一或多个基于FTM的往返时间(RTT)测量值。在一个方面中,FTM过程包含在STA 120与AP 110A之间交换一或多个FTM消息以获得基于第一FTM的RTT测量值。类似地,STA 120和AP 110B可以交换一或多个FTM消息以获得基于第二FTM的RTT测量值。举例来说,FTM消息的交换可以包含STA 120将FTM请求消息发射到AP 110A、从AP 110A接收FTM响应消息、将FTM确认消息发射到AP 110A,并且随后从AP 110A接收定时信息。定时信息可以指示来自AP 110A的FTM响应消息的出发时间,以及在AP 110A处的FTM确认消息的到达时间。在一个实例中,定时信息作为时间戳从AP 110A发送到STA 120。STA 120可随后使用从AP 110A接收的定时信息以及在STA 120自身处产生的定时信息(例如,时间戳)计算基于第一FTM的RTT测量值。将在下文中参考图3描述关于FTM过程的其它细节。
[0033]接下来,在过程块220中,STA 120通过一或多个非启用FTM的AP 112A和112B中的每一个执行非FTM过程以在STA 120与AP 112A和112B之间获得相应的一或多个非基于FTM的RTT测量值。在一个实例中,非FTM过程包含将非FTM消息从STA 120发射到AP 112A、响应于非FTM消息从AP 112A接收非FTM响应消息,以及基于非FTM响应消息的到达时间与非FTM消息的出发时间之间的差异计算非基于FTM的RTT测量值。借助于实例,非FTM消息可以是请求发送(RTS)消息并且非FTM响应消息可以是清除发送(CTS)消息。因此,在一个实施方案中,STA 120经配置以产生对应于当RTS消息被发射时的出发时间的时间戳并且产生对应于当CTS消息在STA 120处被接收时的到达时间的另一时间戳。STA 120可以通过从CTS消息的到达时间减去RTS消息的出发时间来计算非基于FTM的RTT测量值。
[0034]在一个实例中,STA 120计算第二RTT而无需补偿可能通过在非FTM消息的处理中的AP 112A和112B赋予的任何延迟。因此,在AP 112A和112B接收非FTM消息时与在AP 112A和112B发射它们的非FTM响应消息时之间的任何延迟包含于非基于FTM的RTT测量值中,使得非基于FTM的RTT测量值可被称为未经补偿的RTT测量值。
[0035]接下来,在过程块230中,STA 120基于一或多个基于FTM的RTT测量值与一或多个非基于FTM的RTT测量值两者计算STA 120的位置。在一个实例中,STA 120使用基于FTM的RTT测量值和非基于FTM的RTT测量值两者直接地计算STA 120的位置,而无需STA 120的位置的介入确定。也就是说,并非组合基于所述基于FTM的RTT测量值的位置确定与基于所述非基于FTM的RTT测量值的位置确定,本发明的方面可以包含使用基于FTM和非基于FTM的RTT测量值两者执行单个位置确定的STA 120。
[0036]虽然图2将过程200说明为执行FTM过程并且随后非FTM过程,但是其它实例可以包含以相反次序或甚至同时执行所述过程。也就是说,根据本文中的教示STA 120可以首先执行非FTM过程并且随后执行FTM过程,或者STA 120可以通过非启用FTM的AP中的一些执行至少一些非FTM过程,在相同时间周期期间STA 120通过启用FTM的AP执行至少一些FTM过程。
[0037]图3是说明使用FTM和非FTM过程两者确定无线站(例如,STA 120)的位置的过程300的调用流程。过程300是图2的过程200的一个可能的实施方案。
[0038]如图3中所示,过程300包含STA 306从服务器302(例如,对应于图1的服务器140)接收位置辅助数据307的任选步骤。在一个实例中,位置辅助数据307包含一或多个非启用FTM的AP 304的位置和/或一或多个启用FTM的AP 305的位置。
[0039]图3进一步说明包含在STA 306与启用FTM的AP 305之间交换FTM消息308-314的FTM过程301。具体地说,在时间T1,STA 306发射FTM请求消息308,所述消息是在时间T2在启用FTM的AP 305的启用FTM的AP处接收到的。响应于FTM请求消息308,启用FTM的AP 305在时间T3发射FTM响应消息310。FTM响应消息310是在时间T4在STA 306处接收到的。STA 306随后在时间T5发射确认消息312。此外,STA 306可以产生对应于时间T4的第一时间戳和对应于时间T5的第二时戳。在时间T6,启用FTM的AP 305接收确认消息312并且响应于此,产生定时信息消息314,所述定时信息消息在时间T7被发送回到STA 306。定时信息消息314包含FTM响应消息310的出发时间(即,时间T3)以及确认消息312的到达时间(即,时间T6)。在一个实例中,对应于时间T3的出发时间和对应于时间T6的到达时间包含于定时信息消息314中作为由启用FTM的AP 305产生的时间戳。在时间T8接收定时信息消息314之后,STA 306可随后计算第一基于FTM的RTT测量值。在一个方面中,第一基于FTM的RTT测量值是基于时间T3、T4、T5和T6计算的。举例来说,STA 306可以将第一基于FTM的RTT测量值计算为(T6-T3)-(T5-T4)。
[0040]接下来,STA 306可以执行包含在STA 306与一或多个非启用FTM的AP 304之间交换非FTM消息316和318的非FTM过程303。在时间T9,STA 306将非FTM消息316发射到非启用FTM的AP 304的非启用FTM的AP。在一个实例中,非FTM消息316是请求发送(RTS)消息,但是可替代地是数据消息。并且,在时间T9,STA 306产生对应于非FTM消息316的出发时间(即,时间T9)的时间戳。非FTM消息316是在时间T10在非启用FTM的AP 304处接收的,其随后在时间T11将非FTM响应消息318发射到STA 306。在一个方面中,非FTM响应消息318是清除发送(CTS)消息,但是可替代地可以是确认消息。
[0041]STA 306随后在时间T12接收非FTM响应消息318并且产生对应于非FTM响应消息318的到达时间(即,时间T12)的时间戳。STA 306可随后基于时间T9和T12(例如,T12-T9)计算非基于FTM的RTT测量值。如图3中所示,非启用FTM的AP 304可以碰到在时间T10非FTM消息316的接收与在时间T11非FTM响应消息318的发射之间的一或多个延迟。因此,通过STA306计算的非基于FTM的RTT测量值是包含在非启用FTM的AP 304处引发的一或多个延迟(例如,延迟=T11-T10)的未经补偿的RTT测量值。
[0042]如下文将论述,除计算STA 306的位置之外,STA 306可以计算非启用FTM的AP 304的TCF估计值。在一个实例中,TCF估计值是从时间T10到时间T11在非启用FTM的AP 304处遇到的延迟的估计值。
[0043]在STA 306已经计算非启用FTM的AP 304的TCF估计值之后,STA 306可以将TCF估计值发送到服务器302。消息320可以包含用于通过STA 306计算的非启用FTM的AP 304中的每一个的单个TCF估计值或者它可以包含通过对应于通过非启用FTM的AP 304执行的FTM和非FTM过程的STA 306计算的多个TCF估计值的平均值。在一个实例中,服务器302可以存储借助于消息320接收的TCF估计值中的一或多个。服务器302可随后将TCF估计值提供到可能并不是启用FTM的其它无线站。在另一实例中,STA 306可以本地地在STA 306自身处存储一或多个TCF估计值。本地地存储的TCF估计值可随后在未来位置确定中由STA 306利用,其中存在不充足的数目的启用FTM的AP以确定STA 306的位置。
[0044]在一些实例中,STA 120/306经配置以取决于可用于STA 120/306的信息的数量和/或启用FTM和非启用FTM的AP的数目计算与位置确定相关的各种参数(例如,STA120/306位置、非启用FTM的AP位置、启用FTM的AP位置、TCF估计值等)。下文参考图4A到4C描述多个实例使用情况。
[0045]图4A是说明用于无线站(例如,STA 120/306)的位置和非启用FTM的接入点(AP)的周转校准因数(TCF)的联合计算的过程400a的流程图。在过程块410中,无线站获得非启用FTM的AP 304中的一或多个的位置和一或多个启用FTM的AP 305的位置。如上文所提及,无线站可以借助于从服务器302接收的位置辅助数据307获得非启用FTM的AP和/或启用FTM的AP的位置。
[0046]在过程块420中,无线站确定可供使用的启用FTM的AP的数目是否大于第一阈值。也就是说,第一阈值涉及将允许无线站联合地计算无线装置的位置和用于非启用FTM的AP304的至少一个的TCF的启用FTM的AP的数目。如果启用FTM的AP的数目大于第一阈值,那么过程块430包含执行无线装置的位置和用于非启用FTM的AP 304中的一或多个的TCF的联合计算的无线装置。在一个实例中,无线装置的位置和TCF的联合计算包含计算无线装置的位置和TCF两者而无需无线装置的位置的介入确定。也就是说,并非首先确定无线装置的位置并且随后确定非启用FTM的AP的TCF,本发明的方面可以包含执行确定无线装置的位置和非启用FTM的AP的TCF两者的单个过程的无线。
[0047]图4B是说明用于无线站的位置、非启用FTM的AP的位置和非启用FTM的AP的周转校准因数(TCF)的联合计算的过程400b的流程图。在过程400b中,非启用FTM的AP中的一或多个的位置是无线站未知的。因此,在过程块440中,无线站确定可供使用的启用FTM的AP的数目是否大于第二阈值。也就是说,第二阈值涉及将允许无线站联合地计算无线装置的位置、非启用FTM的AP 304中的一或多个的位置和用于非启用FTM的AP 304中的至少一个的TCF的启用FTM的AP的数目。在一个实例中,第二阈值是变量并且涉及待由无线站确定的未知数的数目。也就是说,越多的TCF估计值是未知的和/或越多的非启用FTM的AP位置是待确定的,则意味着需要更大数目的启用FTM的AP用于无线站位置、非启用FTM的AP位置和非启用FTM的AP的TCF估计值的联合计算。在一个方面中,如果可供使用的启用FTM的AP的数目超过未知数的数目,那么满足第二阈值,所述未知数的数目包含待确定的TCF估计值和非启用FTM的AP位置的数目。
[0048]如果启用FTM的AP的数目大于第二阈值,那么过程块450包含执行无线装置的位置、非启用FTM的AP 304中的一或多个的位置和用于一或多个非启用FTM的AP 304的TCF的联合计算的无线装置。在一个实例中,无线装置的位置、非启用FTM的AP 304的位置和TCF的联合计算包含计算无线装置的位置、非启用FTM的AP 304的位置和TCF,而无需无线装置的位置的介入确定。也就是说,并非首先确定无线装置的位置并且随后确定非启用FTM的AP304的位置和/或非启用FTM的AP的TCF,本发明的方面可以包含执行确定无线装置的位置、非启用FTM的AP的位置和非启用FTM的AP的TCF的单个过程的无线。
[0049]图4C是说明用于非启用FTM的AP的周转校准因数(TCF)的计算的过程400c的流程图。在过程400c中,非启用FTM的AP中的一或多个的位置是无线站已知的。因此,在过程块460中,无线站确定可供使用的启用FTM的AP的数目是否大于第三阈值。也就是说,第三阈值涉及将允许无线站计算无线装置的位置并且随后计算用于位置是无线站已知的非启用的AP中的一或多个的TCF的启用FTM的AP的数目。
[0050]如果启用FTM的AP的数目大于第三阈值,那么过程块470包含执行无线装置的位置的计算的无线装置。在一个实例中,无线装置的位置的计算是基于借助于通过启用FTM的AP305执行的FTM过程301获得的基于FTM的RTT测量值通过无线站确定的。接下来,在过程块470中,无线装置基于无线装置的计算出的位置(即,过程块470)并且基于所述基于FTM的RTT测量值(即,经由FTM过程301)和所述非基于FTM的RTT测量值(即,经由非FTM过程303)两者计算非启用FTM的AP 304中的至少一个的TCF。
[0051]图5说明可并入到设备502、设备504和设备506(例如,分别对应于无线站(STA)、基站和服务器)中的若干样本组件(由对应的块表示)以支持无线站的位置确定,如本文中所教示。将了解,这些组件可以在不同实施方案中在不同类型的设备中(例如,在ASIC中、在SoC中等)实施。所说明的组件也可以并入到通信系统中的其它设备中。举例来说,系统中的其它设备可包含类似于所描述的那些组件的组件以提供相似功能性。并且,给定设备可含有组件中的一或多个。举例来说,设备可包含多个收发器组件,其使得所述设备能够在多个载波上操作和/或经由不同技术通信。
[0052]设备502和设备504各自包含经由至少一种指定的无线电接入技术(RAT)与其它节点通信的至少一个无线通信装置(由通信装置508和514表示(在设备504是中继的情况下,为通信装置520))。每个通信装置508包含用于发射和编码信号(例如,消息、指示、信息等等)的至少一个发射器(由发射器510表示)以及用于接收和解码信号(例如,消息、指示、信息、导频等等)的至少一个接收器(由接收器512表示)。类似地,每个通信装置514包含用于发射信号(例如,消息、指示、信息、导频等等)的至少一个发射器(由发射器516表示)以及用于接收信号(例如,消息、指示、信息等等)的至少一个接收器(由接收器518表示)。如果设备504是中继站,那么每个通信装置520可以包含用于发射信号(例如,消息、指示、信息、导频等等)的至少一个发射器(由发射器522表示)和用于接收信号(例如,消息、指示、信息等等)的至少一个接收器(由接收器524表示)。
[0053]发射器和接收器在一些实施方案中可以包括集成装置(例如,实施为单个通信装置的发射器电路和接收器电路),在一些实施方案中可以包括单独的发射器装置和单独的接收器装置,或在其它实施方案中可以其它方式实施。设备504的无线通信装置(例如,多个无线通信装置中的一个)还可包括用于执行各种测量的网络监听模块(NLM)或类似物。
[0054]设备506(以及设备504(如果其不是中继站))包含用于与其它节点通信的至少一个通信装置(由通信装置526以及任选地通信装置520表示)。举例来说,通信装置526可包括经配置以经由基于有线或无线回程与一或多个网络实体通信的网络接口。在一些方面中,通信装置526可以被实施为经配置以支持基于有线或无线信号通信的收发器。此通信可涉及例如发送和接收消息、参数或其它类型的信息。相应地,在图5的实例中,通信装置526示出为包括发射器528和接收器530。类似地,如果设备504不是中继站,那么通信装置520可以包括经配置以经由基于有线或无线回程与一或多个网络实体通信的网络接口。与通信装置526一样,通信装置520示出为包括发射器522和接收器524。
[0055]设备502、504和506还包含可以与无线站的位置确定结合使用的其它组件,如本文中所教示。设备502包含用于提供与例如执行FTM过程、执行非FTM过程和计算无线站的位置相关的功能性(如本文中所教示)且用于提供其它处理功能性的处理系统532。设备504包含用于提供与例如交换FTM和/或非FTM消息相关的功能性(如本文中所教示)且用于提供其它处理功能性的处理系统534。设备506包含用于提供与例如提供位置辅助数据相关的功能性且用于提供其它处理功能性的处理系统536。设备502、504和506分别包含用于维持信息(例如,指示保留资源、阈值、参数等等的信息)的存储器组件538、540和542(例如,各自包含存储器装置)。另外,设备502、504和506分别包含用户接口装置544、546和548,以用于将指示(例如,听觉和/或视觉指示)提供到用户和/或以用于接收用户输入(例如,在例如小键盘、触摸屏、麦克风等等的感测装置的用户致动之后)。
[0056]为了方便起见,设备502、504和/或506在图5中示出为包含可以根据本文中所描述的各种实例配置的各种组件。然而将了解,所说明的块在不同设计中可具有不同功能性。
[0057]图5的组件可以各种方式实施。在一些实施方案中,图5的组件可在一或多个电路中实施,例如,一或多个处理器和/或一或多个ASIC(其可包含一或多个处理器)。此处,每个电路可使用和/或并入至少一个存储器组件以用于存储由所述电路使用以提供此功能性的信息或可执行代码。举例来说,由块508、532、538和544表示的功能性中的一些或全部可以通过设备502的处理器和存储器组件实施(例如,通过执行适当的代码和/或通过处理器组件的适当的配置)。类似地,由块514、520、534、540和546表示的功能性中的一些或全部可以通过设备504的处理器和存储器组件实施(例如,通过执行适当的代码和/或通过处理器组件的适当的配置)。并且,由块526、536、542和548表示的功能性中的一些或全部可以通过设备506的处理器和存储器组件实施(例如,通过执行适当的代码和/或通过处理器组件的适当的配置)。
[0058]图6说明表示为一系列相关功能模块的实例无线站(STA)600。STA 600是STA 120和/或设备502的一个可能实施方案。用于通过一或多个启用FTM的AP中的每一个执行FTM过程以获得相应的一或多个基于FTM的RTT测量值的模块602至少在一些方面中可以对应于例如通信装置508,如本文所论述。用于通过一或多个非启用FTM的AP中的每一个执行非FTM过程以获得相应的一或多个非基于FTM的RTT测量值的模块604至少在一些方面中可以对应于例如通信装置508,如本文所论述。用于基于一或多个基于FTM的RTT测量值和一或多个非基于FTM的RTT测量值两者计算无线站的位置的模块606至少在一些方面中可以对应于例如处理系统532和/或存储器组件538。
[0059]可以与本文中的教示一致的各种方式实施图6的模块的功能性。在一些设计中,这些模块的功能性可被实施为一或多个电气组件。在一些设计中,这些模块的功能性可被实施为包含一或多个处理器组件的处理系统。在一些设计中,这些模块的功能性可以是使用例如一或多个集成电路(例如,ASIC)的至少一部分实施的。如本文中所论述,集成电路可以包含处理器、软件、其它相关组件或其某一组合。因此,不同模块的功能性可例如实施为集成电路的不同子集、实施为软件模块的集合的不同子集,或其组合。并且,将了解(例如,集成电路的和/或软件模块的集合的)给定子集可以提供用于多于一个模块的功能性的至少一部分。
[0060]另外,可使用任何合适的装置来实施由图6表示的组件和功能以及本文中所描述的其它组件和功能。此类装置也可至少部分地使用如本文中教示的对应的结构来实施。举例来说,上文结合“用于图6的组件的模块”所描述的组件也可对应于类似地指定的“用于功能性的装置”。因此,在一些方面中,这些装置中的一或多个可使用如本文中教示的处理器组件、集成电路或其它合适的结构中的一或多个来实施。
[0061]应理解,对本文中使用例如“第一”、“第二”等等名称的元件的任何参考通常不限制那些元件的数量或次序。实际上,这些名称可在本文中用作区别两个或大于两个元件或元件的例子的方便方法。因此,对第一和第二元件的参考不意味着此处可采用仅两个元件或第一元件必须以某一方式在第二元件之前。并且,除非另外说明,否则元件的集合可包括一或多个元件。另外,在说明书或权利要求书中使用的术语形式“A、B或C中的至少一个”或“A、B或C中的一或多个”或“由A、B和C组成的群组中的至少一个”意味着“A或B或C或这些元素的任何组合”。举例来说,此术语可以包含A、或B、或C、或A和B、或A和C、或A和B和C、或2A、或2B、或2C等等。
[0062]鉴于以上描述和解释,所属领域的技术人员将了解,结合本文中所公开的方面描述的各种说明性逻辑块、模块、电路和算法步骤可以实施为电子硬件、计算机软件或这两者的组合。为了清晰地说明硬件与软件的此可互换性,上文已大体就其功能性描述了各种说明性组件、块、模块、电路和步骤。此类功能性是实施为硬件还是软件取决于特定应用及强加于整个系统的设计约束。所属领域的技术人员可以针对每一特定应用以不同方式实施所描述的功能性,但此类实施决策不应被解释为引起对本发明的范围的脱离。
[0063]相应地,将了解,例如一种设备或设备的任何组件可经配置以(或可操作以或适应于)提供本文中教示的功能性。这可以例如通过以下而实现:通过制造(例如,制作)所述设备或组件使得其将提供所述功能性;通过编程所述设备或组件使得其将提供所述功能性;或通过使用某一其它合适的实施技术。作为一个实例,集成电路可制作为提供必备的功能性。作为另一实例,集成电路可制作以支持必备的功能性并且随后经配置(例如,通过编程)以提供必备的功能性。作为又一实例,处理器电路可执行代码以提供必备的功能性。
[0064]此外,结合本文中所公开的方面描述的方法、序列和/或算法可以直接体现于硬件中、处理器执行的软件模块中,或这两个的组合中。软件模块可以驻留在RAM存储器、快闪存储器、ROM存储器、EPROM存储器、EEPROM存储器、寄存器、硬盘、可移动磁盘、CD-ROM,或所属领域中已知的任何其它形式的存储媒体中。示例性存储媒体耦合到处理器,使得处理器可从存储媒体读取信息且将信息写入到存储媒体。在替代方案中,存储媒体可与处理器(例如,高速缓冲存储器)成一体式。
[0065]相应地,还将理解,例如,本发明的某些方面可包含实施如上文参考图2到4C所论述的方法的计算机可读媒体。
[0066]尽管前述公开内容示出了各种说明性方面,但应注意,可在不脱离如由所附权利要求书所定义的范围的情况下作出对所说明的实例的各种改变和修改。本发明并不意图单独限于具体说明的实例。举例来说,除非另外指出,否则根据本文中所描述的本发明的方面的方法权利要求项的功能、步骤和/或动作无需以任何特定次序执行。此外,虽然可以单数形式描述或主张某些方面,但除非明确地陈述对单数形式的限制,否则涵盖复数形式。