cdma tutorial

CDMA Tutorial April 29, 2006Michael SouryalApril 29, 2006 Common Components Encoding, modulation, spreading Common Features/Functionality Power control, diversity, soft handoff System Particulars cdmaOne (IS-95) cdma2000Sources:1. V. Vanghi, A. Damnjanovic, and B. Vojcic, The cdma2000 System for Mobile Communications (Prentice Hall PTR, 2004).2. V. K. Garg, IS-95 CDMA and cdma2000 (Prentice Hall PTR, 2000).2M. Souryal 1CDMA Tutorial April 29, 2006 A way for multiple users to share the channelTime Division Frequency Division Code Division Multiple Access Multiple Access Multiple Access3 InputData FEC Interleaver Modulator SpreaderEncoderChannelOutputDataFECDeinterleaver Demodulator DespreaderDecoder4M. Souryal 2CDMA Tutorial April 29, 2006 Standard component of most digital communications systems Especially important in fading and interference channels FEC encoder adds coded redundancy to the information data stream Decoder uses the redundancy to correct errors caused by channel impairments (FEC a.k.a. “channel coding”) Benefits Ability to operate at a lower bit error rate (BER), for a given signal-to-noise-and-interference ratio (SNIR) Ability to operate at a lower SNIR for a given BER (“coding gain”) Ability to tolerate more users in a multiuser system5 Costs ...