Details

Autor(en) / Beteiligte

• Ki Jun Kim
• Soon Yil Kwon
• Seung Hoon Hwang
• Chae Ha Pak
• Keum Chan Whang

Titel

Comparison of coherent and noncoherent CDMA system in time varying fading channel

Ist Teil von

• Proceedings of Vehicular Technology Conference - VTC, 1996, Vol.2, p.884-888 vol.2

Ort / Verlag

IEEE

Erscheinungsjahr

1996

Quelle

IEEE Xplore

Beschreibungen/Notizen

• The direct-sequence code-division multiple access (DS-CDMA) system has received much attention for digital mobile cellular telephone and personal communication network (PCN) applications. The performance of a coherent CDMA system is compared with that of a noncoherent CDMA system according to the extent of the channel variation and offset frequency. A pilot signal is used for coherent detection. Using a RAKE receiver, we evaluate the BER of the uncoded system analytically considering the estimation error of the carrier phase. Also the power ratio of the pilot signal to the data signal and the integration length of the channel estimator of the coherent BPSK system is optimized according to the fading bandwidth and offset frequency. The required SIR of the BPSK system is compared with that of a DPSK system. Additionally we determine the extent of performance improvement which can be achieved by convolutional coding. The results show that the optimum performance of BPSK is at least 1 dB better in terms of the required SIR than that of DPSK in practical ranges.