Broadband CDMA for Overlaid Cellular PCS

A demonstration of Broadband Code Division Multiple Access (CDMA) for PCS communications overlaid in the 800 MHz AMPS cellular band will be conducted. Broadband CDMA using direct sequence spread spectrum has significant military advantages of jamming immunity and low probability of intercept. It is also the most promising of the new concepts for high capacity commercial cellular radio because of its spectral efficiency and its lower mobile phone power needs. The laboratory demonstration accompanied by theoretical analysis and simulations, will build on previous work that successfully tested non-overlaid Broadband CDMA for non-military applicatons in the 1.9 GHz PCS band. The technical issues to be addressed are: CDMA resistance to jamming, CDMA probability of intercept, mutual interference between CDMA and the overlaid FDMA cellular, near/far CDMA signal strength effects , capacity of CDMA cellular telephone methods, and multipath effects. The quantitative effects of jamming and interference on bit error rate will be measured and simulated. The prototype CDMA transceivers used for the demonstration will utilize a state-of-the-art ASIC chip, the Unisys PA-100 Spread Spectrum Demodulator, providing DS spreading rates up tp 32 MHz. This device had been developed for wideband airborne RF data links, and is being evaluated for very promising applications for both battlefield communications as well as a marketable commercial product. Anticipated Military Benefits/Potential Commercial Applications of the Research or Development: The demonstration will show the antijam and covertness militry features of CDMA overlaid on existing cellular phone spectrum users, for tactical and special operations uses. The potential commercial applications are very significant because of the high cellular capacity of Broadband CDMA as well as reduced mobile phone power and longer battery life.