Signal Processing for Communication Systems
IS-95 uses three families of sequences at once: a long code for scrambling, a short code for cell identity and quadrature spreading, and a set of Walsh–Hadamard codes for the forward channels under one base station. Long code The long code is an m-sequence from a 42-stage LFSR, clocked at the chip rate 1.2288 Mc/s. … Read more
Spread spectrum system, originally developed for military applications, is extremely resistant to unauthorized detection, jamming, interference and noise. It converts a narrowband signal to wideband signal by the means of spreading. The original 802.11 and 802.11b used direct-sequence spreading. From 802.11a onward, Wi-Fi is OFDM. Bluetooth Classic hops; Bluetooth Low Energy hops as well, on … Read more