Narrowband Interference Suppression in Spread Spectrum Cdma Channel Data Noisy Data Pn Sequence Pn Sequence Figure 1: Spreading/despreading Procedure

Narrowband Interference Suppression in Spread Spectrum CDMA H. Vincent Poor, Leslie A. Rusch Code-division multiple-access (CDMA) implemented with direct-sequence spread spectrum signaling is among the most promising multiplexing technologies for cellular telecommunications services, such as personal communications, mobile telephony, and indoor wireless networks [1, 2, 3, 4, 5]. The advantages of direct-sequence spread spectrum for these services include superior operation in multipath environments, exibility in the allocation of channels, the ability to operate asynchronously, privacy, and increased capacity in bursty or fading channels. Also among the attractive features of spread spectrum CDMA is the ability of spread spectrum systems to share bandwidth with narrowband communication systems without undue degradation of either system's performance. In particular, the ability of spread spectrum to provide reliable performance in severe signal-to-noise (SNR) environments and its low energy pro le make the sharing of frequency bands by multiple and disparate users a real possibility. This ability provides a means by which to alleviate overcrowding in the radio frequency spectrum, as well as to allow more user exibility in the choice of modulation format.