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4G Wireless Location Services will Drive Powerful, Content-Rich Applications by Dr. Martin Feuerstein, CTO       9/11/2008 While recent media attention has focused on the deployment of 3G networks in the U.S., the rest of the world is fast at work on the development of the next step in wireless communication—4G wireless networks. Already, both LTE and WiMAX networks—two competing 4G standards—are in development today, promising to be truly broadband networks capable of supporting a new world of advanced voice and data applications. These more powerful, more resilient and more flexible next-generation 4G carrier networks will drive the proliferation of high-bandwidth, low-latency multimedia applications including mixed data, voice, video and location-based services. 4G will leverage Internet Protocol (IP) throughout the network from the radio link through the core network infrastructure, eventually bringing speeds of 20 Mb/sec and higher to wireless devices.  The proliferation of 4G networks also promises to create a convergence in wireless technologies and services on a worldwide scale, creating a single, unified global wireless infrastructure for content-rich applications where location awareness is ubiquitous and transparent. Location-based services will work seamlessly across continents and oceans, driving the wide-scale development and deployment of powerful applications that thrive on frequent and accurate location updates on a mass scale and in real-time. Location awareness will become an integral element—weaved throughout a range of new services and applications. Location-based services are already available on today's 3G networks—most notably on the Apple iPhone 3G—however, these applications are primarily centered on basic turn-by-turn navigation tools. More pervasive and interactive mobile social networks, multiplayer gaming, geo-fencing based coupon advertising promotions and asset tracking will drive the need for high-accuracy, high-yield and low-latency location-based services on 4G networks. And it is the all-IP 4G networks that will act as an enabling platform for these "beyond navigation" applications.  Location-Based Services and 4G Networks   While the iPhone 3G relies on GPS technology to pinpoint the handset's location, most industry experts agree that a GPS-exclusive wireless location solution does not provide the accuracy or reliability needed to drive 4G applications. GPS works great in open-sky environments but is severely limited in dense urban and indoor environments—the concrete and steel canyons of large cities acting as barriers to satellite signal reception. Even Apple has recognized the problems with GPS-only solutions, coupling satellite technology with WiFi on the iPhone 3G. While there are still concerns about a solution that relies on GPS and unmanaged WiFi networks, it is generally accepted that only a hybrid approach using multiple wireless location technologies will provide the accuracy, latency, reliability and yield needed for 4G networks. Figure 1: A 4G Network based on LTE  Existing solutions use a variety of independent location technologies including Assisted GPS (A-GPS), Enhanced Cell-ID (ECID), Uplink Time Difference of Arrival (UTDOA) and unique pattern matching location technologies like Wireless Location Signatures (WLS), but these are essentially standalone technologies, incapable alone of providing the necessary consistency of location performance across all environments. However, pooled together, these technologies can dramatically improve accuracy, leveraging each technology's advantages while mitigating the other technologies' weaknesses. Pattern matching location technologies use the principle that every location has a unique radio frequency signature. Like a fingerprint's pattern of lines and swirls, a location can be identified by a unique set of values including measurements of neighboring cell signal strengths, time delays and other network parameters. A product architecture that leverages existing wireless location technologies to mine network measurement information can determine accurate locations to better than 50 meters in urban areas. As the technologies on devices continue to expand (e.g. 2G, 3G, 4G, WiFi and Bluetooth), the handset signatures are becoming richer, further enhancing accuracy—perhaps one day even providing vertical coordinates, resulting in highly-reliable handset location virtually anywhere. The work done by standards groups such as the Open Mobile Alliance (OMA)—a broad group of wireless carriers, software developers, device and network suppliers and content and service providers with a vested interest in mobility applications—will only help wireless location services vendors leverage this wide net of technologies throughout a global network. In addition to consumer applications, there is a huge opportunity to develop powerful enterprise applications that rely on accurate, reliable and real-time location. Companies can leverage this technology to track inventory and assets around the world, supervise employees as they travel around a service area or target potential customers as they approach storefronts, making location-based services pervasive in the realm of mission-critical business applications. However, it is generally accepted that for the type of applications that 4G promises, the solutions need to be accurate to within tens of meters, make a Time to First Fix (TTFF) in under five seconds and work seamlessly across urban, suburban, rural, indoor and outdoor environments. While we're not there yet, a reliable, robust product architecture that pools information from different location technologies and air interfaces could eventually leverage the power of these rich signatures to achieve greater accuracy, yield and low latency on a global scale. If engineered correctly, this wireless location architecture would help drive the rapid and cost-efficient roll out of the high-bandwidth, low-latency enterprise applications that consumers are going to expect from 4G networks. Figure 2: A New York field trial shows that A-GPS can not provide the accuracy needed in dense urban environments, but a hybrid solution made up of A-GPS and WLS provides much greater accuracy. (SOURCE: Polaris Wireless) Evolving Standards Much of the debate has been centered on whether to embrace the 3GPP Long Term Evolution (LTE) standard or the IEEE Worldwide Interoperability for Microwave Access (WiMAX) standard, both proponents claiming that each one is better suited to meet the demands and challenges presented by 4G carrier networks. LTE is the evolutionary next step up from GSM and UMTS, and has the backing of most wireless carriers—AT&T, Verizon, Vodafone and DoCoMo—who are looking to protect their 2G and 3G investments. Mobile WiMAX, on the other hand, got a head start in time to market and is being deployed by Clearwire in partnership with Sprint. Converge! One Minute Videos The reality, however, is that most vendors are prepared to support either standard—or most likely—both standards. Because both technologies are based on Orthogonal Frequency Division Multiplexing (OFDM) they are more like step-brothers rather than rivals, and should theoretically be able to co-exist and interoperate. The thinking is that LTE networks would be able to support handsets enabled with WiMAX, and WiMAX networks would be able to support LTE handsets. Likewise, 4G applications and location-based services should be seamless, perhaps through OMA standards, engineered to support both wireless protocols on a global scale. The User Plane Approach While many standards developed for 2G (GSM) and 3G (UMTS) are based on a control plane approach to delivering location information over wireless networks, the OMA is focusing on the user plane—a more simple, cost-efficient and, ultimately, a more powerful 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, instead relying on outside providers for application serving—something that they already do very well.  Figure 3: Putting location awareness on the user plane makes the network transparent and generic. (SOURCE: Polaris Wireless) OMA has developed a standard for user plane location called Secure User Plane Location (SUPL), providing a blueprint for how wireless location technology should work on 4G networks. SUPL-enabled handsets—or SUPL-enabled terminals (SET)—connect directly to SUPL servers through IP transport over packet data services, taking advantage of this more powerful, flexible protocol. The wireless data transport is transparent and generic, meaning that it can be LTE, WiMAX or any other data protocol including GPRS/EDGE, UMTS/HSPA, EV-DO or WiFi.  SUPL is a Key to Fast, Cost-Efficient 4G Deployments The benefit to this user plane approach is that there is no need to populate the carrier's network elements with location-specific intelligence since this function has been off-loaded to the SUPL server. Likewise, carriers will not need to upgrade their wireless network infrastructure—a costly, time-consuming process and a major inhibitor to location services deployments today. For this user plane approach, networks can be LTE, WiMAX or neither—it doesn't matter since the wireless network is completely transparent to location-based services and 4G applications. Because carriers will not have to invest in upgrading network hardware, SUPL environments will enable cheaper and faster deployments of wireless location solutions—which promise to be leading drivers of next-generation networks. SUPL environments can run directly off the open Internet—but why would any carrier want to? Private, closed networks are more secure, providing protection, security and privacy while leveraging powerful authentication solutions to make sure only authorized users and applications have access to location information. Closed networks can also be engineered to be faster and more reliable to support mission-critical applications than the open Internet depending on the infrastructure investments carriers or enterprise customers would be willing to make. SUPL environments could be a new revenue source for carriers without requiring a major capital expense. Having highly-accurate location-specific information not only opens the gate for any number of useful business applications, the technology can introduce valuable location information to existing mission-critical solutions. Companies could amend their asset tracking solutions to monitor delivery trucks in real-time and use the information to map out the most efficient routes based on geography, traffic and even weather information. In addition, roadside assistance companies could identify the closest tow truck to a customer needing help, speeding assistance or making sure specific expertise is sent where it is needed. The possibilities are endless. The SUPL-enabled pattern matching location technologies include a location engine residing on the SUPL server that processes location requests by comparing radio parameter values reported by the handset to those in a database of predicted values. A much more accurate approach than ECID—a technology that relies on cell tower information and timing mechanisms and is only accurate to within several hundred meters—pattern matching location technologies work very well in dense urban and indoor environments since they actually take advantage of the complex clutter caused by tall buildings and other obstructions.     Figure 4: The SUPL architecture sits outside the carrier network. (SOURCE: Polaris Wireless)   As aforementioned, a hybrid approach using powerful pattern matching location technology and A-GPS would provide an ever-increasing rich signature, by blending information from both systems that result in a highly-accurate, highly-reliable handset location virtually anywhere—compared to any stand-alone solution. The SUPL Standard Eventually, all handsets sold will be SETs, unlocking secure location-based services on a large scale. OMA started its SUPL standards work in 2003, and Version 1.0 devices are entering the market now. Version 2.0 with enhanced functionality was ratified in 2008 and will be entering the market soon. Improvements continue with Version 3.0 currently in discussions and planning with the goal of providing enhanced reliability and functionality.  These evolving SUPL standards will drive greater location accuracy, performance and network flexibility for 4G networks. The standards will also help drive efforts to further develop the ecosystem around 4G applications, providing guidelines as to how additional functionality and services will be built into the applications. For example, how will the environments be deployed, what will the architecture look like, how will services like billing and authentication be included or how will privacy policies be managed? These are important questions that OMA and its members are investigating today. Instead of debating between LTE and WiMAX, 3GPP and IEEE, 3G and 4G, the community needs to embrace this user plane approach as the next step to wireless location services. Coupled with innovative pattern matching technologies that rely on rich handset signatures to determine exact handset location, the telecommunications industry will soon be able to cost-efficiently create SUPL-enabled solutions that provide the high-accuracy, high-yield and low-latency needed to support and drive powerful 4G applications. About the Author Marty Feuerstein is chief technology officer for Polaris Wireless, where he leads research into position location products. He has more than 20 years of experience in telecom, including positions with manufacturers, service providers and academia. Prior to Polaris, Marty held management and engineering positions with companies including Nortel, Verizon, Lucent Bell Labs and Metawave Communications. He has many publications, more than a dozen patents in wireless telecom and is a frequent panel participant. About Polaris Wireless Polaris Wireless is committed to simplifying and improving the process of location of mobile phones for carriers around the globe by serving as the price/performance leader delivering accurate, reliable and flexible products to support a variety of applications. Since 2003 Polaris has been successfully deploying the only software-based location system that meets FCC E911 Phase II requirements. Polaris is backed by venture capital funds Draper Fisher Jurvetson, Draper Richards and Centre Palisades Ventures. For more information about Polaris Wireless please visit http://www.polariswireless.com . Polaris Wireless Location Signatures(tm) is a registered trademark of Polaris Wireless. Polaris WLS(tm) is a trademark of Polaris Wireless. Send us your response to this article. Learn How to Get Your Column Published on this Site