Allen Telecom Offers Geometrix Network-Based Location System

The Grayson Wireless division Allen Telecom Inc. (Herndon, VA) is throwing its location solution into the E-911 pot. Its Geometrix network-based customer-location solution meets or exceeds FCC E-911 Phase II accuracy and capacity requirements. It is available as a turnkey solution or as a service bureau offering, and to ease integration with existing E-911 operations, the solution interfaces seamlessly with industry-standard E-911 Phase I technology.

Geometrix is an independent overlay in wireless network base stations and mobile switching centers (MSCs), and it is installed without interruptions or delays in service. The system operates transparently to wireless carriers and their customers.

The system uses Time Difference of Arrival (TDOA) or a combination of TDOA and Angle of Arrival (AOA) techniques to provide the location of wireless E-911 calls in urban, suburban, and rural environments.

Features

• Supports a wide variety of cellular and PCS frequencies and air interfaces, including AMPS, TDMA (IS-136), CDMA (IS-95), and iDEN systems.

• Ability to support multiple frequency bands and air interfaces simultaneously without duplicated equipment at cell sites. This provides substantial savings for dual-mode wireless carriers and allows multiple service providers to share a common system to meet the FCC's Phase II requirement.

• Scalable and upgradeable technology, allowing carriers to expand coverage areas, capacity, and air interfaces over time with simple additions to existing equipment.

• Ability to support and enhance value-added wireless location services.

The solution's centerpiece is the Geolocation Control System. Located at an MSC, it manages the entire system, obtains data from Geometrix wireless location sensors at base stations, performs location determination calculations, and reports location coordinates to mobile positioning centers used by public safety answering points (PSAPs).

The system also includes planning tools that can predict the needs of wireless carriers' E-911 location networks by using a combination of propagation models, terrain and morphology data, and location algorithms. The system provides a gateway for maintenance networks using industry standard protocols, which provide 24-hour, 7-day total system monitoring, transparent software upgrades, system backup, configuration modifications, and an interface for remote troubleshooting and repair.

Privacy Issues
The system requires no changes in service, including no modification or replacement of handsets, no new handset functions, and no additional user instructions. To safeguard subscriber privacy, the system determines a wireless user's position only when it is specifically tasked to identify the location of a caller. It also has no knowledge of the caller except that the caller is temporarily using a particular channel through a specific cell site. Geometrix does not initiate position calculations without receiving an explicit instruction, for example, in response to an E-911 call.

The system has demonstrated it meets and surpasses the FCC requirements through extensive data gathering under real-world conditions. It has been field-tested and is available for demonstration in an operating network located in northern Virginia. The network includes deployment of Geometrix equipment at multiple commercial wireless sites, covering an area of approximately 50 square kilometers.

Edited by Ellen Jensen