The present invention relates generally to telecommunication systems, and more particularly to telecommunication systems that receive and process location queries from mobile units or remote applications to determine the position of a particular mobile unit within a communications network.
The Global System for Mobile Communications (GSM) is a popular standard currently in use to provide wireless communications. This standard was developed primarily for voice communications, but is also frequently used to provide data services. The General Packet Radio Service (GPRS) is an extension of the GSM standard that provides data services to GSM mobile devices. Typical applications for GPRS include Internet browsing, wireless e-mail, and text messaging.
The GSM standard is capable of providing a variety of information services to subscribers. Location Services (LCS) is one example of an information service that GSM provides. LCS allows a subscriber or remote application to obtain or determine the location of a GSM mobile unit operating within the GSM network. The location may be determined by the network, based on measurements supplied by the mobile unit, or may be determined by the mobile unit itself and communicated to the network. Various approaches to position estimation may be used, including Uplink Time of Arrival (TOA), Enhanced Observed Time Difference (E-OTD), and assisted Global Positioning System (GPS).
In a standard architecture GSM system, a centralized server known as the Serving Mobile Location Center (SMLC) manages the overall coordination and scheduling of resources required to perform the tasks associated with positioning a mobile unit. It may also calculate the final location of the mobile unit and estimate the accuracy of the position measurement. In performing these functions, the SMLC exchanges information with other entities within the network, such as the mobile unit and/or a location measuring unit or application. The location information may be the position of the mobile unit, measurements from which the position of the mobile unit may be determined, or data otherwise useful in determining the position of the mobile unit.
In a conventional GSM system, the SMLC server communicates with a Gateway Mobile Location Center (GMLC), which is typically the first point at which an external LCS client application accesses a Public Land Mobile Network (PLMN) when providing location services. The GMLC communicates the queries received from the mobile unit to the SMLC so it may perform certain positioning functions as well as provide an initial rough estimate of the mobile unit's location (such as the particular cell site the mobile unit is in).
In the past, it was common for the functionality of the SMLC and the GMLC to be combined into the same physical node. With this configuration, the SMLC and GMLC applications would typically communicate directly with one another according to standard SS7 communication techniques. However, recently, as communication networks have become more distributed in nature, it is becoming more common for the SMLC and the GMLC to be physically remote from one another.
Accordingly what is needed is an efficient and effective way for an SMLC node to interface with a physically remote GMLC node and vice versa.
In view of the foregoing, it would therefore be desirable to provide systems and methods that effectively and efficiently provide a communications interface between remotely located GMLC and SMLC nodes.
It is therefore an object of the present invention to provide systems and methods that effectively and efficiently provide a communications interface between remotely located GMLC and SMLC nodes.
These and other objects of the invention are provided in accordance with the principles of the present invention by providing systems and methods that effectively and efficiently provide a communications interface between remotely located GMLC and SMLC nodes. A method according to a preferred embodiment of the invention may include receiving a location request and location data at a public land mobile network. The public land mobile network may include a servicing mobile location center and a gateway mobile location center. The method may also include arranging the location request and the location data into a predefined format that is useable by the servicing mobile location center; calculating a position of the mobile unit using the servicing mobile location center and/or the gateway mobile location center; arranging data indicative of the calculated position into a format recognizable by the mobile unit, the location application, and/or the location client; and sending the arranged data over the wireless network to the mobile unit, the location application, and/or the location client.
A system according to a preferred embodiment of the present invention may include means for receiving a location request and location data; means for arranging the location request and the location data into a predefined format that is useable by a servicing mobile location center; means for calculating a position of the mobile unit; means for arranging data indicative of the calculated position into a format recognizable by the mobile unit, a location application, and/or a location client; and means for sending the arranged data over a wireless network to the mobile unit, the location application, and/or the location client.
The above and other objects and advantages of the present invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference numbers refer to like parts throughout, and in which:
In operation, mobile unit 102, which may be any suitable mobile communications device such as a cellular telephone, a personal digital assistant (PDA), a handheld PC, a Blackberry™, etc. may issue a position or location request to wireless communication network 104. Network 104, which preferably includes GSM and GPRS communication capabilities, receives this request and communicates it to gateway 106 which may function as interface between wireless communication network 104 and the components typically found incertain portions of a Public Land Mobile Network (PLMN). In some embodiments, the PLMN may include GMLC 108, SMLC 110, location application 112 as well as other known telecommunications components (not shown).
Generally speaking, wireless network 104 includes the resources required to support GPRS functions. Moreover, in some embodiments, network 104 may provide network access control, which is the means by which a user of mobile unit 102 connects to a telecommunications network in order to use the services of that network.
Gateway 106 may include software and/or hardware that allows it to function as a Wireless Application Gateway (WAP) and may also include similar resources or otherwise be configured to allow it to provide Push Proxy Gateway (PPG) functions. However, it will be understood that any other suitable methods, communication or data transfer standards, or other protocols may be used, if desired, by gateway 106 to communicate with wireless network 104.
Location application 112 may be any commercial or proprietary application or system suitable for assisting in determining the position of mobile unit 102. For example, location application 112 may include or communicate with certain location systems that employ Global Positioning System (GPS) measurements or other observation or measurement-based techniques such as Uplink Time of Arrival (TOA), Enhanced Observed Time Difference (E-OTD), suitable for providing information to SMLC 110 or any other system in order to assist in locating mobile unit 102.
Location client 114 may be any suitable external client process requesting location information regarding mobile unit 102. For example, location client 114 may be a software tracking application that informs users of the location of a particular mobile unit 102.
As shown in system 100 of
In the embodiment of
In other embodiments, location application 112 and/or location client 114 may be external application requesting the location information from mobile unit 102. In this case, the request may be processed generally as described above with GMLC 108 and SMLC 110 performing the location calculations (with or without information/data from mobile device 102) with the results being provided to application 112 and/or client 114.
Some of the positioning and control messages that may be used for GMLC 108 to communicate with a remotely located SMLC 110 (and vice versa) in accordance with the principles of a preferred embodiment of the present invention include the following:
RSP Positioning Messages:
In some embodiments, RSP positioning messages may have the following structure:
RSP Control Messages:
In some embodiments, RSP control messages may have the following structure:
The set of messages and the message structures listed above may be thought of as defining a new communication protocol that may sometimes be referred to as the Remote SMLC Protocol (RSP). Some or all of the above messages (and any results or computations associated therewith) may be transported back and forth between remotely located GMLC and SMLC nodes, thus providing an effective and efficient way for these platforms to communicate and cooperate with one another in providing location services to a mobile unit despite being physically separate from one another.
System 100 may be configured such that the messages and structures shown above may be native to both GMLC 108 and SMLC 110 or may require some intermediate processing to be understood by one or both of these processes. In the case where intermediate processing is required, e.g., such as when certain legacy systems are updated, either SMLC 110 or GMLC 108 may be reprogrammed to convert or accept the RSP messages above, or in some embodiments, may require the installation of translation or conversion hardware/software to convert these messages to a desired format (not shown).
In addition, in some embodiments of the present invention, standardized GPRS position and control messages may be converted into the RSP messages above by using the information contained within the messages themselves and rearranging information into the new format as shown in the illustrative examples below:
Additional illustrative message arrangements and formats may be as follows:
3.1.1.3 RSP Measure Position Request—Message coding is similar to the RRLP measure position request with additional parameters specifying the RSP Measure Position Request message type and the transaction ID.
3.1.1.4 RSP Measure Position Response—Message coding is similar to the RRLP measure position response with additional parameters specifying the RSP Measure Position Response message type and the transaction ID.
3.1.1.5 RSP Perform Location Abort/Reset Message
3.1.1.6 RSP PROTOCLO ERROR Message
3.1.1.7 RSP TERMINATION Message
3.1.2 RSP Control Messages
3.1.2.1 RSP APPLICATION CONTEXT Message
3.1.2.2 RSP APPLICATION CONTEXT RESPONSE Message
3.1.2.3 RSP CHECK ALIVE Message
3.1.2.4 RSP CHECK ALIVE ACK Message
3.1.3 Coding of New Message Type on RSP
3.1.4 Coding of Information Element on RSP
3.1.4.1 Element Identifier
3.1.4.2 Transaction_ID
Possible range of Transaction ID value:
00 00 00 00 00 00 to FF FF FF FF FF FF
3.1.4.3 Response Time
The Timer Value field is expressed in units of 500 ms.
3.1.4.4 Application ID
Coding of Application ID (bits 8-3):
000001 A-GPS Application
The Version field (bits 2-1) shall be coded as 00 if not used. If used, it shall be populated with the value assigned by the PDE.
3.1.4.5 Context Status
Coding of Status (bits 8-1):
3.1.4.6 Transaction Error Cause
Coding of Cause (bits 8-1):
3.1.4.7 User Information IE
3.1.4.8 Cause IE
The cause field is coded as follows:
All unassigned codes are spare.
3.1.4.9 Termination Cause IE
The cause field is coded as follows:
All unassigned codes are spare.
3.1.4.10 Generic Information IE
4.0 Abbreviations
The following references are hereby incorporated by reference in their entirety.
Returning now to
GMLC 108 may also include some of the functionality required to support location services. In some embodiments, GMLC 108 is the first node at which location application 112 and/or location client 114 accesses wireless network 104. GMLC 108 may perform certain managerial functions associated with signal routing such as request process signal routing information from a home location register to determine how to route response to locations queries and may assist in calculating the final location of mobile unit 102.
In one embodiment of the present invention, GMLC 108 and SMLC-llO may communicate with one another using a TCP/IP or Ethernet connection that may be initiated by GMLC 108 acting as a client and SLMC 110 acting as a server. When the communication session is established, an application level handshake may be required to ensure that both platforms are communicating with the correct application. A successful handshake may create an RPS interface link in which a mobile unit location related transaction can proceed.
One TCP/IP session may constitute one RPS interface link. In some embodiments, GMLC 108 may establish more than one communication session to create multiple RPS interface links. In this case, each link may be created by successful application level handshaking. A communications session may terminate if either GMLC 108 or SMLC 110 does not receive a status communication from the other within a predetermined period of time (e.g., 30 seconds).
In one embodiment of the present invention, RSP messages relating to the same positioning transaction may be sent and received over the same RSP interface link if multiple such links are active. This may be done to prevent information from these RSP messages from being intermixed in the TCP/IP byte stream.
Information processed by SMLC 110 and GMLC 108 in accordance with the RPS standard disclosed herein may be converted back into standard GPRS format at GMLC 108 or gateway 106 for transmission of requested information back to mobile unit 102 via wireless network 104. This alleviates the need to update mobile units 102 or other portions of the wireless network 104 to recognize RSP messages. Moreover, GMLC 108, SMLC 110, and mobile unit 102 may include or communicate with or include a mapping application program such as Mapquest™ to further process the position information requested into a map type or other format for ease of comprehension by the user.
Flow chart 200 in
At step 206 SMLC 110 may send a location request to mobile unit 102 such as GPS or other positioning system information. In response to receiving such information, mobile unit 102 may send information/data generally indicative of its position (such as psuedo-range information) back to SMLC 110 at step 208. Next, SMLC 110 may process this information, possibly along with other positioning information received from an external source, to determine the location of mobile unit 102 at step 210. At step 212, this location information may be sent to external application and/or clients such as, for example, mobile unit 102, location application 112, and/or location client 114. Next, at step 214, before final transmission to its destination, the location information/data may be converted or mapped from and internal SMLC/GMLC communication format such as the format disclosed herein to standard GPRS, GSM CDMA or other communication format for processing by that application/client.
Thus, systems and methods for locating and communicating location information to a mobile unit are provided. It will be understood that the foregoing is only illustrative of the principles of the invention and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention. Accordingly, such embodiments will be recognized as within the scope of the present invention.
Persons skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which are presented for purposes of illustration rather than of limitation and that the present invention is limited only by the claims that follow.
This application claims the benefit of United States Provisional Patent Application entitled “Method and Apparatus for Location Services Routing Between GMLC and SMLC” filed Nov. 14, 2003, Ser. No. 60/520,023 which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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60520023 | Nov 2003 | US |