KR20020057954A - Method and network for providing to a positioning data - Google Patents

Abstract

The present invention relates to a method for providing arrival time (TOA) positioning data in a wireless communication network 10 that minimizes the use of traffic channels in the network. The method comprises the steps of assigning signaling channel 62 to an idle mobile station 12 in network 10, allowing mobile station 12 to handover directly from signaling channel 62 to traffic channel 66; Causing the mobile station 12 to generate an access burst during handover 68 and using the access burst to provide TOA positioning data to the mobile station 12.

Description

METHOD AND NETWORK FOR PROVIDING TO A POSITIONING DATA}

As the demand for wireless (or cellular) communication increases, communication systems have been developed that can provide high quality services to many users. Such systems include analog systems such as advanced mobile phone systems (AMPS) and digital systems such as global mobile communication systems (GSM) and digital AMPS (D-AMPS). To implement such a system, a cellular based communication device operates in an interference-limited environment in accordance with a frequency reuse plan to maximize capacity and quality. To this end, protocols such as frequency division multiple access (FDMA) in analog systems and time division multiple access (TDMA) in digital systems are used.

Because bandwidth is a limited resource (in terms of physical and regulated), it is often used to divide the available network resources among as many subscribers as possible. One way to most efficiently allocate bandwidth relates to combined TDMA and FDMA (TDMA / FDMA). For example, the 25 MHZ bandwidth can be divided into 124 carrier frequencies individually spaced 200 kHZ, one or more of which are assigned to each base station in the network. Each carrier frequency may in turn be divided in time using the TDMA scheme to define a logical channel. The channel may be divided into dedicated subchannels which are in turn assigned to mobile stations.

Traffic channels, commonly referred to as communication or transport channels, are used to carry voice and data (typically non-command) signals over a network. Traffic channels are defined in GSM using multi-frames, or groups of 26 individual TDMA frames. For 26 frames, typically 24 frames are used for voice or data, one frame is used as the control channel and one frame will not be used.

The control channel, referred to as signaling or common channel, can be accessed by both idle and dedicated mode mobile stations. The common channel is used by the idle mode mobile station to exchange signaling information needed to change to dedicated mode. The mobile system in dedicated mode monitors wireless transmission for handover or other information from the serving base station transceiver. The common channel is defined within a 51-frame multi-frame so that a dedicated mobile station using a 26-frame multi-frame traffic channel (TCH) structure also monitors the control channel.

In other systems, such as code division multiple access (CDMA) or FDMA, other methods are used. In addition to dividing the bandwidth among the subscribers, a traffic channel is assigned to the incoming call. Several methods and protocols are used to increase channel efficiency, connection quality, and the number of potential channels available for subscribers in the area in which the base station operates. The transport channel of the system facilitates communication in the system.

As the use of wireless networks increases, determining the location of a user within the network, i.e., "location" becomes increasingly important. Positioning algorithms and systems are being developed and used to calculate and present the positional coordinates of a user. At the same time, positioning is defined by a government agency (ie FCC) as a standard to be implemented in early 2001.

The arrival time (TOA) positioning mechanism is based on collecting the arrival time (TOA) measurements calculated from the access bursts generated by the mobile station. Access bursts are generated during inter-cell or intra-cell handover and are received and measured by both serving base station transceivers and adjacent base station transceivers (BTSs). Using an access burst to locate a mobile station requires additional hardware at the receiving BTS to accurately measure the TOA of the burst.

In the current TOA positioning method, a mobile station (MS), referred to as a mobile radio, mobile device, or mobile handset in idle mode, is first assigned a signaling channel before paging, authentication and encryption are completed. At this point, the serving mobile location center SMLC then commands the base station controller BSC via the mobile switching center MSC to allocate the first traffic channel. This process is often referred to as positioning call setup. The SMLC then hands the array to an array of location management units (LMUs) that instruct the BSC to perform a location handover (ie, fake handover) to another traffic channel to perform the TOA positioning of the MS from the MS. Send an over access burst.

This use of the transport channel to locate in this way is inefficient and wastes valuable network resources. Using a traffic channel to locate a mobile station in idle mode places more load on the network. As such, means for reducing the use of traffic channels during positioning will provide various advantages.

FIELD OF THE INVENTION The present invention relates generally to cellular communication and applications, and more particularly to a method for providing time-of-arrival positioning data that minimizes the use of traffic channels within a wireless network.

The above features and advantages of the present invention will be more clearly understood in view of the following detailed description in conjunction with the accompanying drawings.

1 illustrates a GSM network in which the present invention may be used.

FIG. 2 illustrates a near structure for a TOA positioning method according to an embodiment. FIG.

3A illustrates channeling while the mobile station is in idle mode.

3B illustrates channeling while the mobile station is in a dedicated mode.

4 illustrates signaling during TOA call setup.

5 illustrates the invention in accordance with one embodiment.

6 is a signaling diagram illustrating the step of positioning a mobile station using a positioning method based on time of arrival (TOA).

Although not shown, corresponding parts are indicated with corresponding reference numerals and symbols in the detailed description.

The present invention provides a method in a wireless communication network that provides time of arrival (TOA) location data that minimizes the use of traffic channels within the network. The present invention provides a new solution for TOA positioning, where an idle MS is first assigned a signaling channel and then handed over directly to the traffic channel. The serving mobile location center (SMLC) instructs the base station controller (BSC) through the mobile service center (MSC) to direct location handover (ie, fake handover) from the signaling channel to the reserved traffic channel for positioning handover. Do it. One advantage provided by the present invention is that the load on the network is reduced without connecting unnecessary network resources.

A method for providing time of arrival (TOA) location data that minimizes the use of traffic channels within a wireless communication network is described in one embodiment. The method includes assigning a signaling channel to an idle MS in the network and allowing the mobile station to handover directly from the signaling channel to the traffic channel. The SMLC in communication with the BSC commands the BSC to perform a handover. That is, the SMLC transmits a positioning handover command to the BSC through the MSC. Then, the BSC serving the MS performs handover from the signaling channel to the traffic channel.

The method may further comprise causing the MS to generate an access burst during handover. The step is performed by sending a handover access burst from the MS to a set of location management units (LMUs) used in one embodiment, the access burst being used to provide TOA location data to the MS.

Also described is a method of providing time of arrival (TOA) location data to an MS, wherein the wireless communications network is adapted to communicate via a mobile station controller (MSC) to a base station controller (BSC) serving the MS and is communicatively coupled service. Has a mobile location center (SMLC). The method includes causing a location service (LCS) information request (TOA) to be sent from the SMLC to the MSC. Next, a position information command (TOA) is generated and transmitted from the MSC to the BSC. This step can be performed by reporting the location information (TOA) to the MSC. The reporting step precedes the sending of the LCS Information Report (TOA) from the MSC to the SMLC.

The method may further comprise causing the LCS information request to be sent from the MSC to a plurality of location management units (LMUs) adapted to measure the TOA access bursts generated by the MS. The LMU then relays the LCS Information Response to the MSC. Once the response has been sent, the SMLC performs a location check, which is then sent to the MSC.

The method also includes allocating a Standalone Dedicated Control Channel (SDCCH) to the MS, sending a handover command to the MS, performing a handover of the MS from the SDCCH to the traffic channel, and the handover step of the MS. Generating an access burst while the multiple LMUs measure the TOA of the access burst for positioning of the MS. This step is accomplished by assigning a timer to generate an access burst during handover. If the time allotted to the timer expires before the handover is successful, a handover failure signal is sent from the MS to the BTS to communicate with the BSC for further command.

The technical advantage of the present invention is the use of fewer traffic channels during positioning handover. Therefore, the load on the network is reduced.

Another technical advantage is that in-cell handover can be performed in less time and less complex for each TOA positioning request from the mobile station in idle mode.

Although making and using various embodiments of the invention has been described in detail below, it should be understood that the invention provides many available inventive concepts that can be implemented in a wide variety of specific situations. The specific embodiments described herein are merely specific ways to make and use the invention, and are not intended to limit the scope of the invention.

In order to better understand the present invention, reference is made to FIG. 1, which shows a GSM network 10 in which the present invention may be used. Mobile station 12 includes mobile equipment 22, including a terminal such as a cellular telephone, and a subscriber identity module (SIM) 24, wherein SIM 24 is an international mobile device that identifies subscribers of the GSM network 10. Subscriber identity (IMSI), authentication secret key, and other information. Mobile equipment 22 is specifically identified by International Mobile Equipment Identity (IMEI). IMEI and IMSI are independent, thereby allowing the mobility of the user's personality.

The BSS 14 includes two parts, a base station transceiver (BTS) 26 and a base station controller (BS) 28. The BTS 26 communicates with the BSC 28 across the standardized Abyss interface to operate between the elements. The BTS 26 houses a radio transceiver defining a cell to process the radio-link protocol to the mobile station 12. In the metropolitan area, a considerable number of BTSs 26 can be deployed. The BSC 28 manages radio resources for one or more BTSs 26, and there may be several BSCs 28 within the BSS 14. BSC 28 handles radio-channel setup, frequency hopping, and handover. The BSC 28 provides a connection between the mobile station 12 and the MSC 30 of the network subsystem 16.

The central element of the network subsystem 16 is the mobile switching center 30, which acts like a typical switching node of a public switched telephone network (PSTN), and registers, authenticates, updates location, handovers, and moves to subscribers. It provides all the features needed to handle mobile subscribers such as call routing. These services are provided in connection with several functional entities formed with the network subsystem 16.

MSC 30 provides a connection to fixed network 32, which may include, for example, a PSTN or Integrated Services Digital Network (ISDN). Home location register (HLR) 34 and visitor location register (VLR) 36 along with MSC 30 provide mobility capability and call routing for the GSM network. In particular, the HLR 34 includes management information of subscribers registered in the corresponding GSM network 10 according to the current position of the mobile station 12. Similarly, VLR 36 now includes selected management information from HLR 34 needed to provide subscriber service and control calls to each mobile station located within its geographical area controlled by itself 36.

The present invention provides a method for positioning a mobile station 12 within the coverage area of a GSM network 10 or other public land mobile network (PLMN), which is more efficient than the prior art positioning method. A TOA positioning system according to one embodiment of the present invention is generally shown and indicated at 40 in FIG. 2. The system 40 may deliver time of arrival (TOA) location data for the requesting agent 54 that is operated and maintained at one or more external locations. The request agent 54 sends a request for positioning via a gateway mobile location center (GMLC) 52 that provides an interface for the system 54 to the system 40. GMLC 52 also includes the functionality needed to provide location services (LCS) functionality to interact with other entities within system 40 to determine the location of MS 12.

Therefore, GMLC 52 provides an entry node to an external LCS client for use in accessing PLMN 46. GMLC 52 may request routing information from home location register (HLR) 36. After registration authentication, GMLC 52 sends a location request to VMSC 30 to receive position data from VMSC 30. Once the location request has been processed by the VMSC 30, the VMSC 30 communicates with the BSC 28 and the serving mobile location center (SMLC) 50. SMLC 50 includes algorithms, methods, and systems needed to support LCS. The SMLC 50 manages the overall coordination and scheduling of resources needed to perform the positioning of the MS 12. It also calculates the final position estimate within a certain level of accuracy.

Moreover, SMLC 50 controls the number of LMUs 48 to make air interface measurements to assist in locating or placing MS 12 in an area serviced by system 40. The SLMC 50 is managed with the type and capability of the measurements generated by each of its LMUs 48. Although only one LMU 48 is shown in the system 40, three or more such LMUs are used to position the MS 12 after measuring the TOA by trigonometry. As such, LMU 48 is representative of a number of LMUs typically used for TOA measurements. Signaling between the SMLC 50 and the LMU 48 is carried through the MSC 30 serving the LMU 48. The measurements returned by the LMU 48 to the SMLC 50 have a general state that can be used for one or more positioning methods.

Alternatively, the functionality of SMLC 50 and GMLC 52 may be combined at the same physical node, combined at an existing physical node, or present at several nodes of system 40. SMLC 50 and GMLC 52 are not interconnected, but communication is provided through VMSC 30. When the VMSC 30 and GMLC 52 are in different PLMNs 46, they are interconnected via an air interface.

Referring to FIG. 3A, a location handover, generally indicated as 60, in accordance with the prior art changes from a signaling channel (eg, a standalone dedicated channel (SDCCH)) 62 to a first traffic channel (TCH) 64; It is then shown to include a change to the second traffic channel 66. During idle mode, mobile station 12 is assigned SDCCH 62 within network 10. Then, handover of the mobile station 12 is performed from the signaling channel to the reserved traffic channel 64. Positioning handover may also occur when the mobile station is in dedicated mode, as shown in FIG. 3B. In dedicated mode, traffic channel 64 is already allocated so that assignment to second channel 66 is done directly during handover. Therefore, a second traffic channel 66 is reserved and allocated for positioning handover by the system 40. An access burst 68 generated by the MS 12 during handover is used to provide the TOA location data to the MS 12.

The overall positioning process as shown in Figures 3A and 3B illustrates the current TOA positioning method. The existing TOA positioning method allows the MS 12 in idle mode to be first assigned a signaling channel before paging, authentication and encryption are completed. The SMLC 50 instructs the BSC 28 serving the MS 12 via the MSC 30 to establish a traffic channel 64 (or set up a location call). The SLMC 50 then instructs the BSC 28 to perform a location handover (or fake handover) to another traffic channel to handover to the LMU used to measure the TOA of the access burst from the MS 12. Transmit an access burst 68. This method of performing location handover is inefficient because it uses the resources of two traffic channels 64 and 66.

As described above, the current TOA positioning is provided to establish a positioning call before sending a TOA positioning LSC information command message to the MS 12 in idle mode. Referring to FIG. 4, during TOA positioning call setup, the signaling sequence for the TOA positioning method of the present invention is shown and generally indicated at 70. Call setup 70 begins at step 72, where SMLC 50 is adapted to assign traffic channel 64 to be communicated to MSC 30 later. The allocation of traffic channel 64 is then changed while a message is sent from the MSC 30 to BSC 28 (step 74).

At traffic channel assignment (step 74), channel activation (step 76) is performed by the BSC 28 serving the MS 12 and sent to the BTS 26. The BTS 26 is then adapted to send a channel activation confirmation to the BSC 28 (step 78). An assignment command is then sent from the BSC 28 to the MS 12 (step 80). Then, a setting indication is performed and sent from the BTS 26 to the BSC 28 (step 82). After the setting indication (step 82), the completion of the assignment is performed by the MS 12. The assigned traffic channel confirmation is then sent from the MSC 30 to the SMLC 50.

5, a simplified process diagram of the present invention is shown and generally indicated at 90. In essence, a method is described for providing time of arrival (TOA) location data that minimizes the use of traffic channels within a network. The signaling channel 62 is assigned to an idle mobile station 12 in the network. Then, handover of the MS 12 is performed directly from the signaling channel 62 to the traffic channel 66. Then, the MS 12 is adapted to generate an access burst during the handover 68, while the access burst is used to provide TOA positioning data to the MS 12.

The method of the present invention allows to reduce the allocation of the second traffic channel during positioning handover 68, thus reducing the use of traffic channels in the network. Moreover, inner-cell handover to the same channel or from the signaling channel to the traffic channel is achieved without requiring additional allocation of the second traffic channel. This makes the TOA positioning method less complicated, less time for each TOA positioning request from the MS in the active mode, and less signal for the TOA positioning method.

6 is a signaling diagram illustrating the steps of positioning the MS 12 using a positioning method based on arrival time (TOA), according to one embodiment of the invention. Upon receiving a location request from a location service (LCS), the serving mobile location center (SMLC) 50 sends an LCS information request (TOA) to the mobile station controller (MSC) 30 (step 105). As such, SMLC 50 is responsible for fulfilling the location request. It should be appreciated that one or more SMLCs 50 may be located within each PLMN 46 of the network. Once the MSC 30 has received the LCS information request for TOA positioning, the MSC 30 sends a location information command for the TOA positioning to a base station controller (BSC) 28 serving the mobile station (110). . The BSC 28 then sends a location information report for the TOA positioning to the MS 12 controller 30 (step 115). The location information report for TOA positioning is then sent from the mobile station controller 30 to the SMLC 50 (step 50).

Once SMLC 50 has received the LCS Information Report for TOA positioning, the LCS Information Request is sent from SMLC 50 to MSC 30 (step 125). The LCS information request is then sent from the MSC 30 to the plurality of location management units 48 (step 130). The LMUS 48 is responsible for providing these measurements to the SMLC 50 by making positioning measurements for use in calculating the position of the MS 12. All communications to and from the LMUS 48 are transmitted over the air interface. Therefore, each LMU 48 is in wireless communication with an associated base station controller (BTS) 26. The SMLC 50 is responsible for selecting which LMUS 48 should make positioning measurements. As such, SMLC 50 sends an LCS Information Request message to each such selected LMUS 48 (130).

Once the LMUS 48 receives the LCS information request (step 130), the BSC 28 attempts to begin the location handover 68 process. The location handover sends a handover (HO) command message instructing the MS 12 to perform a handoff to a BTS 26 that the BSC 28 serves or a target BTS (not shown) on a particular channel. Is generated when (at 135). The handover command message also indicates the TDMA frame number at which the MS 12 must begin sending an access burst. When the MS 12 begins sending an access burst in a handover access message (step 145), the LMU 48 makes a time of arrival (TOA) measurement of the access burst. Since the handover is a location handover and not a radio related handover, the BTS 26 will not respond to the handover access message, and the MS 12 will expire when the timer in itself 12 expires (step 150), It will stop sending access bursts. Thereafter, MS 12 returns to the old channel to which it was assigned and sends a handover failure message to BSC 28 (step 155).

TOA measurements are sent from the LMUS 48 to the SMLC 50 via the LCS information response to be used to assist in the calculation of the geographic location of the MS 12. After SMLC 50 calculates the location of MS 12, this location is sent to the LCS client requesting location. The requesting client may be located within MS 12, within MSC 30, or at an external node 54, such as an intelligent location (IN) node. Once the LCS has received the requested information, positioning capabilities are sent from the SMLC 50 to the MSC 30 (step 170).

Although the invention has been described in connection with typical embodiments, such description is not intended to limit the invention. It will be apparent to those skilled in the art that, in connection with the above description, as well as other embodiments of the present invention, the above-described exemplary embodiments can be variously modified and combined. Therefore, the appended claims should cover any such modifications and embodiments.

Claims (13)

A method for providing arrival time (TOA) positioning data in a wireless communication network that minimizes the use of traffic channels within the network. Assigning a signaling channel to an idle mobile station in the network; Direct handover of the mobile station from the signaling channel to a traffic channel; Causing the mobile station to generate an access burst during the handover; Using the access burst to provide TOA location data to the mobile station. The method of claim 1, And the allocating step is performed by causing a base station controller (BSC) serving the mobile station to perform a handover from the signaling channel to the traffic channel. The method of claim 2, And the allocating step is performed by causing a serving mobile location center (SMLC) in communication with the BSC to instruct the BSC serving the mobile station to perform a handover after a specific period of time. Way. The method of claim 3, wherein And the allocating step is performed by transmitting a positioning handover command to the BSC through the MSC. The method of claim 1, And the step of causing the mobile station to generate an access burst is performed by sending a handover access burst from the mobile station to a location management unit (LMU) configured for TOA measurement. In a wireless communication network, a method of providing time-of-arrival (TAO) positioning data to a mobile station (MS), the network adapted to communicate via a mobile station controller (MSC) to a base station controller (BSC) serving the MS. A method of providing time-of-arrival location data having an associated mobile location center (SMLC), Causing a location service (LCS) information request (TOA) to be sent from the SMLC to the MSC; Generating a location information command (TOA) to be transmitted from the MSC to the BSC; Causing an LCS information request to be sent from the MSC to a plurality of location management units (LMUs) adapted to measure the TOA access bursts generated by the MS; Allocating a standalone dedicated control channel (SDCCH) to the MS; Transmitting a handover command to the MS; Performing handover of the MS from the SDCCH to a traffic channel; Causing the MS to generate an access burst during the handover phase so that the plurality of LMUs measure the TOA of the access burst to locate the MS. The method of claim 6, Wherein the step of generating the location information command (TOA) to be transmitted from the MSC to the BSC further comprises reporting the location information (TOA) to the MSC. The method of claim 7, wherein And the reporting step precedes the step of transmitting an LCS information report (TOA) from the MSC to the SMLC. The method of claim 6, And wherein the method further comprises requesting LCS information from the MSC. The method of claim 10, And wherein said transmitting step precedes the relaying of an LCS information response from said plurality of LMUs to said MSC. The method of claim 11, And wherein the relaying step precedes the step of performing positioning performed by the SMLC. The method of claim 6, And wherein said transmitting step involves assigning a timer to said handover for use in TOA positioning. The method of claim 14, And allocating the timer prior to causing a handover signal to be sent to the plurality of LMUs upon expiration of the timer.