Location:Technical Trends in Wireless Location Services

The worldwide wireless location services technical landscape has developed largely according to geographic region. Asian wireless network operators, specifically Japan and Korea, paved the way for value-added wireless location services, focusing on GPS and A-GPS solutions. Europe also started early, using Cell-ID technology for their first commercial wireless services and specialized Personal Navigation Devices (PNDs) for general consumer GPS services.

In North America, the major wireless network operators began investing in wireless location technologies in the late 1990s to meet regulatory guidelines for handling emergency services 911 calls. At that time, network operators debated the advantages of two location technologies: Network-based solutions that could deliver ubiquitous location to all subscribers in the 125-meter accuracy range and; Handset solutions that could provide sub-fiftymeter accuracy for A-GPS equipped mobile devices.

The regulatory agencies left network operators to choose their technical location solutions independently. GSM operators AT&T and T-Mobile chose network solutions. CDMA operators Sprint, Verizon, and Alltel chose A-GPS handset-based solutions, based on Qualcomm's gpsOne Control Plane technology. Nextel, the packet data iDEN operator, deployed a standards-based GSM network location capability along with GPS-capable handsets.

These operator choices define the current technical landscape for commercial locationbased services in North America. This technical landscape has led to a robust location services ecosystem that is poised for the longawaited commercial value-added services success. These technical trends are somewhat unique to North America, but may be used as guidelines for other regions as new services and capabilities are added.

COMMERCIAL SERVICES EVOLUTION
Once the emergency services infrastructure was deployed, wireless network operators reviewed their location assets. They determined that core capabilities were in place, but expected capabilities, like support for data oriented services, were not covered in their standards- based deployments. Privacy management, which is not a component of E911, had not been developed, and map content and Originally built on E-911 the North American wireless location services marketplace today offers a number of successful consumer and enterprise applications. The paper discusses technical roadmap and landscape for commercial location services in North America data were confined to emergency call service boundaries.

Nextel led the way by opening J2ME A-GPS capabilities on Motorola handsets, which enabled developers and enterprises to access MS-based or autonomous GPS location data. A World Wide Reference Network delivered almanac data to help the handset calculate its position. The application services community delivered navigation, enterprise tracking, and other services. Nextel branded a mobile resource management service called Mobile Locator. These GPS-based services, along with their unique push-totalk capabilities, allowed Nextel to command the highest ARPU in the region. Sprint used their Control Plane AGPS capabilities deployed for E911 to support commercial applications for their enterprise customers. They exposed ParlayX terminal location APIs through a gateway that also provided presence, messaging, and geofencing. Sprint added a User Plane capability to support Personal Navigation services. Then in 2005, Sprint acquired Nextel, adding a third location network infrastructure. These have been rationalized into a single location network spanning all access technologies, now giving Sprint a powerful platform to support a wide variety of location business models. Verizon utilized their E911 location technology vendor to add a separate commercial-based User Plane network.

They mandated a unified privacy management infrastructure and offered a common geospatial server for map display, geocoding, and points of interest (POIs). Because Verizon's BREW development community had already been successful before location, BREW was chosen as the user interface technology for the handset and services distribution model. Verizon deployed two key consumer-branded offers, the flagship VZW Navigator and the Verizon Chaperone Family Minder service. Verizon created specific BREW APIs for location, privacy management and geospatial access. As a result of Verizon's technical capabilities and a well-thoughtout certification process for application developers, key 3rd Party-consumer offerings are now coming to market using their core network location capabilities. Verizon has succeeded in providing a unified technical framework for location services.

AT&T(before their merge with Cingular) launched Cell-ID-based services utilizing their standards-based GSM infrastructure. As part of a branded offer, they provided portal-based services for Yellow Pages and a Friend Finder. Although it was a fine effort, the portfolio never gained wide user acceptance. In 2006, AT&T and Cingular merged to form AT&T Mobility. The new AT&T Mobility has launched autonomous GPS mobile phones with a personal navigation service and an enterprise tracking service. The iPhone, launched with Google Maps, uses an alternative location technology that takes advantage of WiFi and other available data to position the user.

TECHNICAL TRENDS
The North American wireless network operators chose specific technical paths to move from E911 to commercial services. As observed across the various network operators, this can be encapsulated in five dominant technical trends.

Trend One - User Plane A-GPS Is the Technical Backbone

All successful commercial location services are based on User Plane A-GPS technology. Cell-ID and other location determination technologies can be used as a fallback, but consumers have an expectation of high location accuracy, now that GPS has become mainstream. Personal navigation, a core service, requires GPS-equipped mobile devices. A-GPS is superior to autonomous-only GPS technology, since assisted GPS data improves timeto- first-fix and increases accuracy indoors and in other satellite-challenged environments.

Although Control Plane technology has the potential to address a larger handset base, many legacy North American handsets are not "certified" for services beyond 911. This can significantly reduce the addressable legacy handset population. GSM operators who deploy standards-based SUPL with GMLC/SMLC elements will increase their addressable markets beyond the A-GPS base with Cell-ID. Cell-ID technology can adequately support certain services.

We can now add the availability of alternative location sources, including WiFi hotspots. Google Maps on the iPhone uses this and even though it has deficiencies in accuracy, and can't be used for personal navigation, it does provide orientation with a nice user interface.

Although addressable market size for Cell-ID and WiFi could be a current advantage over A-GPS, most of the marketing programs that drive service adoption are centered around the new devices.

Trend Two - Operators Centralize Privacy Management

Privacy management was not a part of the E911 infrastructure. Although Nextel helped contribute to a vibrant location services ecosystem by launching commercial services without a consolidated privacy infrastructure, this was not a trend followed by other operators. Most North American network operators have taken or are taking the 'high road' position in providing user control over location information. They have installed or are deploying centralized privacy management infrastructure beyond standards-based GMLC or MPC capabilities. This trend appears to be independent of regulatory or mandated guidelines and is viewed as good technical and business practice. For tracking-type location-based applications, mobile-initiated location push agents may be used to support what would be a normal network-initiated service. This can circumvent traditional privacy norms for locate or tracking services, because the handset can access and push location which is then made available to Locators. The privacy "contract" in these cases is then left exclusively to the application provider and their relationship with the user. Current standards-based privacy management does not address day and time filters, such as, "Do not locate me between 5 p.m. and 7 a.m. or on weekends." Consequently, mobile operators are now relying on the middleware vendor community to provide common or centralized privacy management, focused on Network Initiated service flow to support locate & track services.