Direction-Finding for Second-Generation Mobile Cellular Radio / Personnel Communication Service

Period of Performance: 12/18/1998 - 06/18/1999


Phase 1 SBIR

Recipient Firm

Viasat, Inc.
2290 Cosmos Court
Carlsbad, CA 92009
Principal Investigator

Research Topics


Mobile Cellular Radio (MCR) or Personal Communications Service (PCS) handsets that utilizes second-generation digital access schemes present a significant challenge to DF systems. Handsets utilize either Time Division Multiple Access (TDMA) or Code Division Multiple Access (COMA) to communicate with the basestation. In both cases the networking complexity far exceeds that of first generation systems. Handset power control algorithms designed to extend battery life and minimize Co-Channel Interference (CCI) at the basestation result in low power transmissions and time varying handset output power. CCI is a significant challenge to overcome in successful DF exploitation of second generation MCR/PCS systems and is further exacerbated by multipath and dispersive channels that randomize the arrival times of CCI. A radical new approach to Direction Finding, applying Per Survivor Processing (PSP), offers the opportunity to achieve large performance improvements (e.g. interference rejection, rapid acquisition, multipath mitigation) over conventional techniques. PSP algorithms have been developed and simulated for MCR/PCS waveforms in dense urban environments. The focus of this proposed Phase I effort will be to develop an implementation capable of demonstrating the performance improvement of PSP applied to the mobile DF application. BENEFITS: The primary benefit of this multi-phased SBIR program is the implementation high-performance, robust and cost effective processing to determine the Angle-of-Bearing to MCR/PCS handsets. These capabilities have obvious extensions to other DoD services requiring low cost, high performance DF systems for digital signals. The benefits also extend to government and commercial entities that operate private communication networks and potentially to location applications for cellular 911 calls.