Joseph Garodnick

Impact on capacity to AMPS jamming CDMA/CDMA jamming AMPS in adjacent cells

The authors address the mutual interference caused by the coexistence of narrowband code division multiple access (N-CDMA) and narrowband cellular telephone technologies, i.e., advanced mobile phone system and time division multiple access (AMPS and TDMA). It is shown that when adjacent service areas are using AMPS or TDMA, a dead zone of up to two cells is required before N-CDMA can be deployed. The resulting capacity of the N-CDMA service area is lessened to an extent dependent upon the service area geometry. The dead zone can be extensive enough where the N-CDMA would yield only marginal capacity improvement over AMPS and TDMA.

Capacity limitations due to adjacent cell dissimilar technologies

A direct sequence spread spectrum code division multiple access (CDMA) communication system for cellular or PCN applications should be designed to use the entire bandwidth allocated. In this way the peak power spectral density is minimized. However, some CDMA systems have been designed to have a bandwidth which is much less than the allocated bandwidth. Such narrowband CDMA (N-CDMA) systems lack the LPI characteristics of spread spectrum. The authors address the mutual interference caused by the coexistence of N-CDMA and existing narrowband cellular telephone technologies (AMPS FDMA or TDMA). It is shown that when adjacent service areas are using AMPS or TDMA a dead zone of up to two cells is required before N-CDMA can be deployed. The resulting capacity of the N-CDMA service area is lessened to an extent dependent upon the service area geometry. The dead zone can be extensive enough where the N-CDMA would yield only marginal capacity improvement over AMPS and TDMA. Furthermore, significantly higher N-CDMA mobile transmit power would be required than would be true without adjacent cell interference.<<ETX>>

Broadband code division multiple access - An NDI technology: One phone on post and in battle

It is shown that B-CDMA (broadband code division multiple access) does not suffer from fading. As a result, the same technology can be used on post, for a secure WPBX, secure wireless access or secure cellular communication. Thus, secure, wireless, reliable voice and data (i.e., multimedia) communication can be achieved on post without wiring the post. The same system can be moved onto the battlefield to provide secure, wireless, cellular service to a moving base station. Mobility, in this case, also means flexibility since if a base station is destroyed, the mobile users can, within 1 bit, handoff to an alternate moving base station. The authors show that a commercially developed technology, B-CDMA, used for cellular telephony, wireless PBX and wireless access can, simply, by changing the PN code (TRANSEC) and adding encryption (COMSEC), be changed into a highly secure military system for use on-post and in the moving battlefield of the future. Thus, B-CDMA is the perfect NDI system for use by the DoD.<<ETX>>