SS-CDMA Flexible Wireless Network: Implementation of Approximately Synchronized CDMA Modem for Uplink

概要

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We have proposed an intracell uplink of a spread-spectrum code-division multiple-access (SS-CDMA) flexible wireless network based on approximately synchronized (AS) CDMA. Since the AS-CDMA has no co-channel interference, complicated transmission power control (TPC) is not required. A modem of the AS-CDMA has been designed and implemented for the Japanese 2.4GHz industrial, scientific and medical (ISM) band. Using the implemented modem, the degradation of E_b/N_0 from the theoretical limit is 1.0dB at a bit error rate (BER) of 10^<-3>. Under 2-user environment, the degradation of carrier-to-noise ratio (CNR) is 0.5 dB at a BER of 10^<-3> when the desired-to-undesired signal ratio (DUR) is -20.3dB. We have evaluated BER performances in cases of varying carrier frequency offset and median DUR with computer simulation. Under 8-user environment, at the carrier frequency offset of 0.3 ppm, the BER with the DUR of -16dB is found to be 10^<-3>. Using the AS-CDMA with a 4-step open-loop TPC technique, the design of intracell uplink is available.
社団法人電子情報通信学会の論文
2002-03-01