WO2008089688A1 - A method, device and system for measuring a round-trip delay - Google Patents

Abstract

A method, device and system for measuring a round-trip delay are provided. The method includes that a terminal receives the second message from a service basic station, and a position indication information or a measuring basic station number information is carried in the second message; the terminal choices one or more than one basic stations which can realize the position to act as the measuring basic stations based on the position indication information, or the terminal choices correspondence number basic stations to act as the measuring basic stations based on the measuring basic station number information; the terminal and the choice measuring basic station implement a ranging process, and gain a value of round trip delay RTD between the terminal and the measuring basic station. In the provided method method, device and system for measuring the RTD, by designating that the scan is based on position in the scanning process clearly, the terminal can choice correspondence number basic stations to implement the ranging process based on a position requirement, and because it is not have to report the RTD measuring result after implementing the distance measuring processes with all of the consecutive basic stations, it raises the position rate observably.

Description

 Method, device and system for measuring round trip delay

 The present invention relates to the field of wireless communications, and in particular, to a method, a device, and a wireless access system for measuring a Round Trip Delay (RTD) in a wireless system. Background technique

 In a wireless communication system, in order to maintain the quality of a wireless communication link between a terminal and a network, a mechanism is needed to adjust parameters such as relative time, transmission power, and frequency offset of the terminal and the network. This process is called ranging. ( Ranging ). In the Orthogonal Frequency Division Multi Access (OFDMA) system, there are three types of Ranging: 1) initial Ranging based on competition;

 2) periodic Ranging;

 3) Ranging during the switch.

 The basic difference between the three Ranging methods is that the CDMA codes used come from different sets.

 When the initial Ranging is applied to the initial access of the network, the terminal has synchronized the downlink data of the network, and obtains some configuration parameters of the uplink, but needs to randomly select the access slot and the CDMA codeword;

 The purpose of periodic Ranging is to detect the change of the status of the wireless link. Once the status of the wireless link changes, the corresponding parameter adjustment needs to be made;

 The Ranging in the handover process is similar to the initial Ranging, but it is possible that the target base station (BS) has pre-allocated the relevant Ranging resources to the terminal.

In the current WiMax system, the initial Ranging based on contention is described as follows: 1. The terminal synchronizes the downlink data of the BS, parses the uplink transmission parameters of the BS broadcast, and then A Ranging slot and a CDMA codeword are randomly selected and sent to the BS.

 2. After receiving the CDMA codeword, the BS cannot determine which terminal is transmitting the CDMA codeword, and only broadcasts one RNG-RSP (Ranging Response) message. The RNG-RSP message includes the CDMA codeword and the Ranging slot in which the CDMA codeword is received. In this way, the terminal can use this information to determine whether the RNG-RSP is for itself. The RNG-RSP message also includes some adjustment information on time, power, and frequency offset, and status information of Ranging.

 3. If the RNG-RSP message indicates that the status information of Ranging is continue, the terminal needs to adjust according to the adjustment information in the RNG-RSP message, and then continue to transmit the CDMA codeword.

 4. If the RNG-RSP message indicates that the status information of the Ranging is successful, the BS also carries the CDMA-Allocation-IE (CDMA Allocation Information Element) in the transmitted UL-MAP (Uplink Resource Correspondence Table) message. The role of the CDMA-Allocation-IE is to indicate a physical resource that the terminal can use to send RNG-REQ (Ranging Request) messages.

 5. After receiving the RNG-REQ message, the BS responds with RNG-RSP, this time.

The RNG-RSP message contains a basic connection identifier (CID) assigned to the terminal. The initial Ranging is over.

6. The terminal maintains a clock, and the terminal must receive the RNG-RSP before the clock expires. The Ranging process contains measurements of the RTD. RTD measurements are important in network access, handover, and LoCation Services (LCS) positioning. When the network is connected and switched, if the RTD is not measured, the uplink data cannot be transmitted. Since there may be more than 4 terminals in a BS, and the distance between each terminal and the BS is different, the time at which each terminal signal arrives at the BS is different. Therefore, both the terminal and the BS are required to know the current RTD between the terminal and the BS, so that the time axes at both ends can be freely converted. RTD is a very important parameter when positioning LCS. It defines the distance from the terminal to the BS. Observed Time Difference Of Arrival (OTDOA) In the method, the RTD is measured to obtain the distance difference between the terminal and the two BSs, thereby calculating the current position of the terminal. In the Cell-ID / Relative Time Difference (RTD) positioning mode, after determining the cell where the terminal is located, if the RTD is known, the positioning area can be reduced from one cell to one to the BS. On the ring, the effect of increasing the positioning accuracy is achieved.

 In the prior art, positioning between the terminal and the measurement base station can be performed by scanning. However, in the prior art, it is impossible to distinguish whether the scanning is performed by the access scanning or the positioning scanning. After the scanning is started, the terminal and the neighboring base stations are required to perform the Ranging process, and the corresponding RTD is obtained and reported to the network side, and the network side according to the terminal. The RTD value reported between the reported neighboring base stations locates the terminal, so the positioning speed is slow. Moreover, when the purpose of the scanning is only to locate, it is not necessary to measure the base station to allocate resources for the terminal, but because the measurement base station in the prior art cannot distinguish whether the purpose of the current scanning is a positioning scan, the measurement base station is The terminal allocates unnecessary related resources, which causes waste of resource allocation. Summary of the invention

 Embodiments of the present invention provide methods, devices, and systems for measuring RTDs that improve positioning speed by indicating positioning scans.

 An embodiment of the present invention provides a method for measuring a round trip delay, including:

 The terminal receives the second message sent by the serving base station, where the second message carries the positioning indication information or carries the measured base station quantity information;

 The terminal selects one or more base stations that implement positioning according to the positioning indication information as the measurement base station, or the terminal selects a corresponding number of base stations as the measurement base station according to the measured base station quantity information;

 The terminal performs a ranging process with the selected measurement base station to obtain a round-trip delay RTD value between the terminal and the measurement base station.

An embodiment of the present invention provides a wireless access system, including a base station and a wireless terminal, where the base The station sends a second message to the wireless terminal, where the second message carries the location indication information or carries the measured base station quantity information;

 The terminal selects one or more base stations that implement positioning as the measurement base station according to the positioning indication information; or selects a corresponding number of base stations as the measurement base station according to the measurement base station quantity information, and performs a ranging process with the selected measurement base station. And obtaining a round-trip delay RTD value between the terminal and the measurement base station.

 An embodiment of the present invention provides a base station, including:

 a first instruction unit, configured to send a second message to the terminal, and carry the positioning indication information or the measurement base station quantity information;

 The first ranging unit is configured to perform a ranging process with the terminal.

 The embodiment of the invention provides a wireless terminal, including:

 a second instruction unit, configured to receive a second message that is sent by the base station to carry the positioning indication information or measure the quantity information of the base station;

 a second ranging unit, configured to select one or more base stations that implement positioning according to the positioning indication information as a measurement base station; or select a corresponding number of base stations as measurement base stations according to the measured base station quantity information, and select the measured base station The ranging process is performed to obtain a round-trip delay RTD value with the measurement base station.

 The method, the device and the system for measuring the RTD provided by the embodiment of the present invention clearly indicate that the scanning is based on the positioning during the scanning process, and the terminal may select a corresponding number of base stations to perform the ranging process according to the positioning requirement, and therefore does not have to be associated with all neighboring base stations. After performing the ranging process, the RTD measurement results are reported to achieve a significant increase in positioning speed. DRAWINGS

 1 is a schematic diagram of a signaling flow for performing RTD measurement by using a scanning process according to an embodiment of the present invention; FIG. 2 is a schematic structural diagram of a base station according to an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of a wireless terminal according to an embodiment of the present invention. detailed description

 The method for measuring an RTD provided by the embodiment of the present invention includes:

 The serving base station sends a scan response (MOB-SCN-RSP) message to the terminal, and carries the positioning indication information or carries the measurement base station quantity information in the MOB-SCN-RSP message;

 The terminal selects one or more base stations that perform positioning according to the positioning indication information carried in the received MOB-SCN-RSP message as the measurement base station, or the terminal selects a corresponding number of base stations as the measurement base station according to the carried measurement base station quantity information; The selected measurement base station performs a ranging process to obtain a round-trip delay RTD value between the terminal and the measurement base station.

 The method for measuring RTD provided by the embodiment of the present invention is described in detail below with reference to the accompanying drawings.

 Embodiment 1: The first message is sent by the terminal to the serving base station, and the positioning scan measurement RTD is started. The specific signaling process is shown in Figure 1, including:

 The terminal sends a first message to the serving base station. For example, the first message may be a scan request (MOB-SCN-REQ) message, and the location request information is carried in the MOB-SCN-REQ message, indicating that the scan is out. For the purpose of positioning.

 2. After receiving the MOB-SCN-REQ message sent by the terminal and carrying the positioning request information, the serving base station may determine the range of the measuring base station according to the determination, and measure the number of the base stations, and obtain some parameter information for speeding up the positioning scanning for the terminal. For example, the serving base station returns a MOB-SCN-RSP message to the terminal, and carries the number of base station information for performing the ranging process. Optionally, the candidate measurement base station list may also be carried, and the candidate measurement base station information is indicated in the candidate measurement base station list;

3. The terminal selects a corresponding number of base stations as the measurement base station according to the number of base stations sent by the serving base station; if the serving base station further sends the candidate measurement base station list, the terminal may select the measurement base station from the list of candidate measurement base stations, or may further The base station is selected from the base station whose signal strength is greater than the set threshold, and the terminal and the selected measurement base station perform ranging. Cheng. Optionally, in the foregoing Embodiment 1, when the terminal determines that the current scan is for the purpose of positioning, the terminal and the measurement base station perform the ranging process, and carry the positioning indication information in the RMM-REQ message. After receiving the RNG-REQ with the positioning indication information, the measurement base station does not allocate resources to the terminal, for example: the uplink air interface resource and the basic connection identifier are not allocated to the terminal.

 Optionally, the terminal may also report the selected measurement base station to the serving base station; the serving base station separately notifies each measurement base station, and the ranging initiated by a certain terminal (which carries the terminal identifier in the notification message) is based on the positioning purpose. , the terminal does not need to be allocated resources allocated when accessing ranging.

 Optionally, in order to implement the differentiated location scanning and the access scanning, the existing CDMA codeword may also be divided into a part of the CDMA codeword for positioning scanning, and the positioning indication information may be used to locate the scanned CDMA codeword. The terminal transmits a CDMA codeword for positioning scanning to the measurement base station during the ranging process, and after receiving the CDMA codeword for the positioning scan, the measurement base station does not allocate the resource allocated for accessing the ranging. Or transmitting the CDMA codeword in the negotiated resource region for positioning, and measuring the CDMA codeword sent by the base station after receiving the resource region for positioning, the terminal is not allocated for the terminal when the access ranging is allocated. Resources.

 4. The terminal reports the RTD value obtained by the measurement base station in the ranging process to the serving base station through the scan report (MOB-SCN-REP) message; or reports the service base station to the network side gateway or the network side. A network entity dedicated to location calculations.

 In the foregoing Embodiment 1, the first information further carries the positioning interaction identifier information used to identify the positioning process.

Embodiment 2: The serving base station actively sends a second message to the terminal, indicating that the positioning scan is performed. The difference between the second embodiment and the first embodiment is that the serving base station actively sends a second message to the terminal, for example, the serving base station actively sends the MOB-SCN-RSP to the terminal, or sends the paging broadcast MOB-PAG-ADV message. The MOB-SCN-RSP message or the MOB-PAG-ADV carries the positioning indication information; the terminal selects one or more of the positioning indicators according to the positioning indication information. The base station acts as a measurement base station. The location indication information may only indicate that the purpose of the trigger scan is to locate, and may also specify the minimum number of base stations that need to be scanned.

 Preferably, the positioning indication information is a specific positioning method, for example, the serving base station is

The MOB-SCN-RSP message or the MOB-PAG-ADV message directly indicates the positioning method used for this positioning, such as the Cell-ID/RTD method or the OTDOA method. After obtaining the specific positioning method information, the terminal determines the number of base stations scanned according to the positioning method. If cell-ID/RTD positioning is indicated, scanning can be stopped after scanning one base station; if OTDOA positioning is used, the terminal will stop scanning at least after scanning 3 base stations.

 Preferably, the positioning indication information may also be positioning accuracy information, and the terminal determines the number of scanning base stations according to the positioning accuracy requirement sent by the serving base station.

 The mapping method and the correspondence between the positioning accuracy and the number of scanning base stations can be negotiated by the network side and the terminal during the terminal accessing the network. For example, in the registration (REG) or Subscriber basic capability (SBC) process, the terminal sends the mapping method configured by itself and the mapping between the positioning accuracy and the number of scanning base stations to the network side (if the terminal itself has This configuration information, this step is optional); the base station obtains the obtained (authentication process, or network configuration value) positioning method and the correspondence between the positioning accuracy and the number of scanning base stations and the information sent by the terminal (if the terminal configuration has been reported) ) to compare and determine a set of correspondences to send to the terminal.

 In the same manner as the first embodiment, the terminal and the measurement base station may perform a ranging process, and may send a CDMA codeword dedicated to the positioning scan to the measurement base station; or send the CDMA codeword in the negotiated specific resource region for positioning; or The RNG-REQ message sent to the measurement base station carries the positioning indication information, etc., indicating that the current ranging process is used for positioning.

 In the foregoing Embodiment 2, the MOB-SCN-RSP message sent by the serving base station to the terminal or

The MOB-PAG-ADV message may also carry the candidate measurement base station list information; the terminal may select from the received candidate measurement base station list, or may further select the measurement base station to perform from the base station whose signal strength is greater than the set threshold value. Ranging process. In the foregoing embodiment 2, the second information further carries the positioning interaction identifier information used to identify the positioning process.

 In the foregoing Embodiment 1 and Embodiment 2, because the MOB-SCN-RSP message or the MOB-PAG-ADV message carries the positioning indication, indicating that the purpose of the scanning is positioning, the terminal may select a corresponding number of base stations to perform ranging according to the positioning requirement. The process does not have to report the RTD measurement result after performing the ranging process with all the neighboring base stations, so that the positioning speed can be improved.

 At the same time, in the methods described in Embodiments 1 and 2, since the measurement base station can clearly know that the purpose of the current scan is based on the location scan, the terminal is not allocated resources allocated when accessing the ranging. It not only saves unnecessary resource allocation process, but also improves the utilization of network resources.

 According to the method for measuring round-trip delay provided by the foregoing embodiment of the present invention, the present invention provides a wireless access system, including a base station and a wireless terminal. among them:

 The base station sends a second message to the wireless terminal, where the second message carries the positioning indication information or carries the measured base station quantity information, for example, the second message includes a MOB-SCN-RSP message or a MOB-PAG-ADV message;

 The terminal selects one or more base stations that implement positioning as the measurement base station according to the positioning indication information; or selects a corresponding number of base stations as the measurement base station according to the measured base station quantity information, and performs measurement with the selected measurement base station. From the process, the round-trip delay RTD value between the terminal and the measurement base station is obtained.

 The second message sent by the base station to the terminal may further carry the candidate measurement base station information; the terminal may select a measurement from the candidate measurement base station, or may further select a base station whose signal strength is greater than a set threshold. The base station performs a ranging process.

 A schematic diagram of a specific functional structure of the base station is shown in FIG. 2, including:

a first instruction unit, configured to send a second message to the terminal, carrying the positioning indication information or measuring the number of base station information, for example, the second message includes a MOB-SCN-RSP message or a MOB-PAG-ADV message; a first ranging unit, configured to perform a ranging process with the terminal;

 Optionally, it also includes:

 a first receiving unit, configured to receive a round-trip delay between the terminal reported by the terminal and the measurement base station

RTD value.

 The specific functional structure diagram of the wireless terminal is shown in FIG. 3, and includes:

 a second instruction unit, configured to receive a second message that is sent by the base station to carry the positioning indication information or the quantity of the base station, for example, the second message includes a MOB-SCN-RSP message or a MOB-PAG-ADV message;

 a second ranging unit, configured to select one or more base stations that implement positioning according to the positioning indication information as a measurement base station; or select a corresponding number of base stations as measurement base stations according to the measured base station quantity information, and select the Measuring a base station performing ranging process, and acquiring a round-trip delay RTD value between the base station and the measuring base station;

 Optionally, it also includes:

 a second reporting unit, configured to report an RTD value obtained by the measurement base station during ranging, for example, by using an RTD value obtained by each measurement base station in the ranging process on the MOB-SCN-REP message;

 Optionally, it also includes:

 And a second sending unit, configured to send, to the serving base station, a first message that carries the positioning request information, for example, the first message includes a MOB-SCN-REQ message.

 In summary, the method, device, and system for measuring an RTD provided by the embodiments of the present invention clearly indicate that the scanning is based on positioning during the scanning process, and the terminal may select a corresponding number of base stations to perform a ranging process according to the positioning requirement, since it is not necessary to All neighboring base stations report the RTD measurement result after performing the ranging process, thereby significantly improving the positioning speed. The spirit and scope of the Ming. Thus, it is intended that the present invention cover the modifications and variations of the inventions

Claims

Claim  A method for measuring a round trip delay, characterized in that it comprises:  The terminal receives the second message sent by the serving base station, where the second message carries the positioning indication information or carries the measured base station quantity information;  The terminal selects one or more base stations that implement positioning according to the positioning indication information as the measurement base station, or the terminal selects a corresponding number of base stations as the measurement base station according to the measured base station quantity information;  The terminal performs a ranging process with the selected measurement base station to obtain a round-trip delay RTD value between the terminal and the measurement base station.  2. The method according to claim 1, wherein the second message is a scan response MOB-SCN-RSP message, or  The second message is a paging broadcast MOB-PAG-ADV message.  3. The method of claim 1, further comprising:  The terminal reports the RTD value obtained during the ranging process to the network side.  The method according to claim 1, wherein the positioning indication information comprises a specific positioning method or positioning accuracy information;  The terminal determines the number of measurement base stations according to the positioning method or the positioning accuracy information, and selects a corresponding number of measurement base stations to perform a ranging process.  The method according to claim 4, wherein the number of measurement base stations corresponding to the positioning method or the positioning accuracy is determined by the network side and the terminal.  6. The method according to any one of claims 1-5, wherein the second message further carries candidate measurement base station information;  The terminal selects the measurement base station from the candidate measurement base station or further from a base station whose signal strength is greater than a set threshold value. The method according to claim 1, wherein the terminal sends a first message carrying the positioning request information to the serving base station before receiving the second message sent by the serving base station. The method according to claim 7, wherein the first message sent by the terminal is a scan request MOB-SCN-REQ message, and the positioning request information is carried in the MOB-SCN-REQ message;  The terminal receives the MOB-SCN-RSP message returned from the serving base station, and the MOB-SCN-RSP message carries the determined number of measured base stations, or carries the candidate measurement base station information.  The method according to claim 1, wherein the terminal and the measurement base station perform a ranging process, and send a CDMA codeword for positioning scanning to the measurement base station, where the positioning indication information can be used to locate the scanned CDMA codeword. Form of existence; or  Sending a C D M A codeword in the negotiated resource area for positioning;  Or the RNG-REQ message carries the positioning indication information by using the ranging request sent to the measurement base station;  The positioning indication information indicates that the current ranging process is for positioning.  The method according to any one of claims 7-9, wherein the second information further carries positioning interaction identification information used to identify the positioning process.  The method according to any one of claims 7-9, wherein the first message further carries positioning interaction identification information used to identify the positioning process.  A wireless access system, comprising a base station and a wireless terminal, wherein the base station sends a second message to the wireless terminal, where the second message carries the positioning indication information or carries the measurement base station quantity information;  The terminal selects one or more base stations that implement positioning as the measurement base station according to the positioning indication information; or selects a corresponding number of base stations as the measurement base station according to the measurement base station quantity information, and performs a ranging process with the selected measurement base station. And obtaining a round-trip delay RTD value between the terminal and the measurement base station. The radio access system according to claim 12, wherein the second message sent by the base station to the terminal is an MOB-SCN-RSP message, and the MOB-SCN-RSP message is The candidate measurement base station information is also carried in the middle;  The terminal selects, from the candidate measurement base station, or further from a base station whose signal strength is greater than a set threshold, the measurement base station to perform a ranging process.  A base station, comprising:  a first instruction unit, configured to send a second message to the terminal, and carry the positioning indication information or the measurement base station quantity information;  The first ranging unit is configured to perform a ranging process with the terminal.  The base station according to claim 14, further comprising:  The first receiving unit is configured to receive a round-trip delay RTD value between the terminal reported by the terminal and the measurement base station.  16. A wireless terminal, comprising:  a second instruction unit, configured to receive a second message that is sent by the base station to carry the positioning indication information or measure the quantity information of the base station;  a second ranging unit, configured to select one or more base stations that implement positioning according to the positioning indication information as a measurement base station; or select a corresponding number of base stations as measurement base stations according to the measured base station quantity information, and select the measured base station The ranging process is performed to obtain a round-trip delay RTD value with the measurement base station.  The wireless terminal according to claim 16, further comprising: a second reporting unit, configured to report an RTD value obtained during the ranging process with each measurement base station. The wireless terminal according to claim 16 or 17, further comprising: a second sending unit, configured to send a first message carrying the positioning request information to the serving base station.