Radio Transmission Systems
2.1 Direct Sequence Code Division Multiple Access (DS-CDMA)
2.1.1 Principles of DS-CDMA DS-CDMA is a radio-access technology that enables multiple access based on a spread spectrum system. Figure 2.1a shows how DS-CDMA works [1–3]. The transmitted data sequence is spread across the spectrum after being encoded by spreading codes, each of which is assigned uniquely to each user at a higher rate than the symbol rate of the information data. [Wideband Code Division Multiple Access (W-CDMA) spreads the information data over a 5 MHz band per carrier.] The spread high-speed data sequence is referred to as chip and...