Current geolocation technique is not reliable and accurate in all geo location condition. It will be very accurate and reliable in open environment like highway but it won’t perform as accurately in the street of NYC. So under such circumstances this geo location technique is not reliable so this limitation inspired for the development of geo location technique based on 4G wireless technologies such as LTE. This article is an overview on LTE architecture which will play major role in developing new geo location technique which will overcome on limitation of current geo location technique based on 3G.
APPROACHES FOR LBS
Depending upon how the location information is delivered over the wireless networks, two approaches for LBS are defined.
CONTROL PLANE APPROACH
Control plane location architectures exploit the capabilities of the circuit-switched network and the signaling layer to extract location from inside and through the wireless intelligent network
These architectures are well designed for taking 'geographic snapshots' of many mobile resources carrying several different lightweight devices .With this type of architecture, network-based location queries can be initiated without any device intervention. The devices can be located regardless of their in-use or available state. Control plane architecture offer advantages like smart-client operating system independence and little-to-no device battery power consumption.
Control plane location access methods fit particularly well within larger enterprise IT applications such as field service automation, fleet management/dispatch and sales force automation. These applications typically depend on several other integrated IT systems including call center systems, corporate email servers, CRM systems, etc., and use these systems in conjunction with wireless location and geospatial servers to enhance larger capabilities of the application in support of automated business information flows and real-time communications.
In this context, location is used as a feature to enhance communications by triggering inbound or outbound notifications based on business conditions or observations defined by geographic zones
USER PLANE APPROACH
User plane networks take the location intelligence out of the carrier's mobile network elements and allow handsets to connect directly to location servers through IP, where the servers can be inside or outside the wireless service provider's network. The wireless network is therefore transparent to location applications, eliminating the need for carriers to build location performance directly in 4G networks. User plane location architectures are designed to enable rapid-fix location updates. In user plane location architectures, application intelligence usually resides within the mobile client rather than server-side. Distinct advantages of this approach include the ability to quickly update location locally on the device with minimal network costs, ability to use location locally within a smart client application, and inexpensively push location to servers for processing - all possible through secure IP connections independent of the circuit-switched network. User plane location access methods fit particularly well within user-initiated device centric applications such as navigation, gaming, high-frequency location polling for tracking, photomarking, geocaching and other applications that make use of user-generated content.
LTE CONTROL PLANE LOCATION ARCHITECTURE
The most important technology behind LBS is obviously the location information, which can be gathered by using a network based location detection method. The diagram above shows the control plane location architecture for LTE.
The Gateway Mobile Location Centre (GMLC) contains functionality required to support LBS. In one PLMN (Public Land Mobile Network), there may be more than one GMLC. The GMLC is the first node an external LCS client accesses in a GSM , UMTS or LTE network. The GMLC may request routing information from the HLR (Home Location register) or HSS (Home Subscriber Server). After performing registration authorization, it sends positioning requests to either the VMSC (Visited Mobile Switching Centre), SGSN (Serving GPRS Support Node) or MSC (Mobile Switching Centre) Server and receives final location estimates from the corresponding entity.
Location Registers (LR) are database functions storing information typically used in the routing of signaling information.The CSCF provides session control for subscribers accessing services within the IM (IP Multimedia) CN. In essence the CSCF is a SIP Server. It has responsibility for interacting with network databases such as the HSS for mobility and AAA (Access, Authorization and Accounting) Servers for security.
The P-CSCF is the initial interface (SIP Server) between the mobile and the IMS. The address of the P-CSCF is discovered either as part of the SM (Session Management) procedures involved with establishing IP connectivity. That is, the address of the P-CSCF may be provided during the PDP Context Activation process.
The diagram shows flow of information when a user (UE) requests a location based service for example Public Safety Answering Point (PSAP). As UE is talking to PSAP, the latter collects the location based information for the UE from GMLC by exchanging signaling messages through some intermediate entities. Thus the call is served by fetching the location based information from the network itself rather than relying on the UE to provide the same.
LTE SECURE USER PLANE LOCATION ARCHITECTURE:
System and Subsystem Descriptions
1) SUPL Location Platform:
In the above figure we can see that the SUPL Location Platform (SLP) consists of an SUPL Location Center (SLC) and SUPL Positioning Center (SPC). The SLC and SPC may be integrated into a single system. The Lup interface is used to deliver messages for SUPL Service Management and SUPL Positioning Determination. It may also be possible to separate the SLC and SPC functionality into separate systems within the SLP.
There are two different communication modes between SET and SLP:
- Proxy Mode: The SPC system will not have direct communication with the SET. In this environment the SLC system will act as a proxy between the SET and the SPC.
- Non-Proxy Mode: The SPC system will have direct communication with the SET
A) SUPL Location Center (SLC):
The SLC system coordinates the operations of SUPL in the network and performs the following functions as it interacts with the SUPL Enabled Terminal (SET) over User Plane bearer:
1. SUPL Privacy Function (SPF): The SUPL Privacy Function is the function of ensuring the privacy of a SET User is honored. The following must be considered:
1. Adhere to the target SET User privacy setting regardless of Network Initiated or SET Initiated services
2. Adhere to notification and verification settings of the target SET User
3. Allow for future emergency and lawful override regulations that may apply to the target SET User
2. SUPL Initiation Function (SIF): The SUPL Initiation function provides a mechanism for a SUPL network to start a transaction with a SET. The initiation function is of special importance in enabling SUPL Network Initiated Services
1. The SIF starts its transaction by using one of the following methods:
2. WAP Push Access Protocol (PAP)
3. SMS directly in an MNO environment
3. SUPL Security Function (SSF): The SUPL Security function enables the SUPL network to authenticate and authorize the SET and enables the SET to authenticate and authorize the SUPL network. This is important in safely enabling both Network Initiated and SET Initiated SUPL Service. The SUPL Security function also provides confidentiality and data integrity
4. SUPL Roaming Support Function (SRSF): SUPL roaming occurs when a SET leaves the service area of its H-SLP. The service area of an H-SLP includes the area within which the H-SLP can provide a position estimate for a SET or relevant assistance data to a SET without contacting other SLPs. It should be noted that an H-SLP service area is not necessarily associated with the service area(s) of the underlying wireless network(s).
5. SUPL Charging Function (SCF): The SUPL Charging Function (SCF) is responsible for charging activities within the SLP. This includes charging of MLS Application, SUPL Agents and SET Users. The main task for SCF is to collect appropriate charging related data and data for accounting between SUPL providers. Additionally, SCF may authorize activities in SLP based on assessment of available charging data.
6. SUPL Service Management Function (SSMF): SUPL Service Management Function is the function of managing locations of SETs. This function stores, extracts, and modifies the location information of a target SET. During the execution of this function, the integration with charging, privacy, security, QoP functions SHALL be considered.
7. SUPL Positioning Calculation Function (SPCF): The position calculation function performs the function of calculating the position of a SET.
B) SUPL Positioning Center (SPC):
The SPC supports the following functions:
1. SUPL Security Function (SSF): The SUPL Security function enables the SUPL network to authenticate and authorize the SET and enables the SET to authenticate and authorize the SUPL network. This is important in safely enabling both Network Initiated and SET Initiated SUPL Service. The SUPL Security function also provides confidentiality and data integrity
2. SUPL Assistance Delivery Function (SADF): The assistance data delivery function generates and delivers available assistance data, which is used for the measurement or the calculation of a SET position.
3. SUPL Reference Retrieval Function (SRRF): The reference data retrieval function is the function of retrieving GPS reference data from a GPS reference network. Reference data is needed to generate assistance data.
4. SUPL Positioning Calculation Function (SPCF): The position calculation function performs the function of calculating the position of a SET.
2) SUPL Enabled Terminal (SET):
The SET supports the procedures defined in SUPL as it interacts with the network over the User Plane bearer. The SET may support one or more of the following functions depending on its capabilities and the SUPL Provider’s business rules:
1. SUPL Privacy Function (SPF): The SUPL Privacy Function is the function of ensuring the privacy of a SET User is honored. The following must be considered
1. Adhere to the target SET User privacy setting regardless of Network Initiated or SET Initiated services
2. Adhere to notification and verification settings of the target SET User
3. Allow for future emergency and lawful override regulations that may apply to the target SET User
2. SUPL Security Function (SSF): The SUPL Security function enables the SUPL network to authenticate and authorize the SET and enables the SET to authenticate and authorize the SUPL network. This is important in safely enabling both Network Initiated and SET Initiated SUPL Service. The SUPL Security function also provides confidentiality and data integrity
3. SUPL SET Provisioning Function (SSPF): SUPL SET Provisioning Function is the function that manages the provisioning for the SET. The SET SHALL be provisioned with the address of the Home SLP.
Key features of SUPL:
1) In this user plane there is no need to load the carrier with the information regarding the location as it is already present in the SUPL server that is the carrier will not need to upgrade its wireless infrastructure which is a cost and time consuming process. The network doesn’t matter whether LTE or Wi MAX as the network is completely transparent to location based services. Because of these reasons the SUPL environment provides cheaper and faster deployment of wireless location solution.
2) SUPL environment can run directly off the open internet. Private closed network are more secure which provide protection, security and privacy of data and allow only authorized user and application to access the location information. Closed network can also be designed to be faster and secure to support mission- critical application than the open internet due to which enterprise prefer to use these systems.
3) SUPL environment has accurate location specific information. Because if this many business application and technologies can introduce valuable location information to existing mission critical solutions. Eg: companies could track the delivery trucks in real time and could be able to find out shortest path. In this way there are endless possibilities.
4) SUPL enabled pattern matching location technologies include a location engine which is in the SUPL server which processes the location requests by comparing the radio parameter values which are present in its database because of which it gives the most accurate information. These pattern matching location technologies work well in dense urban and indoor environment as they actually take an advantage of complex clutters caused by tall building and other obstructions.
About the Author: Sheetal
I am Sheetal Thakur, earned MS in Telecommunication from New Jersey Institute Of Technology. Served as Technical Customer Support Assistant and Wireless Research Associate. My goal is to transit my enthusiasm, creativity & experience into a position, where I continue to provide the strategic and tactical leadership critical to retaining valued customers of an organization.
Article source: http://www.4gwirelessjobs.com/articles/article-detail.php?Potential Technologies for Wireless Geolocation in LTE&Arid=MTIx&Auid=MTA5
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