Analysis and minimization of loss of process gain with A/D conversion in DS-CDMA

Author

Yagyu, Mitsuhiko ; Kinjo, Shigenori ; Yamaguchi, Hirohisa

Author_Institution

Tsukuba R&D Center, Texas Instrum., Japan

Volume

5

fYear

1999

fDate

1999

Firstpage

2476

Abstract

This paper presents an analytical equation to estimate the process gain actually derived in the despreading process in DS-CDMA systems. The A/D converter (ADC) generates quantization and saturation noise, which reduces the process gain. The probability density function (PDF) of the ADC output is analytically expressed so that the PDF of the quantized and despread signal is shown. Then the SNR of the despread signal is obtained as the ratio of the expectation and the variance given by the PDF. Further by using the analytical equation, the optimum reference value of the AGC can be obtained without numerous computer simulations. In the wideband-CDMA system, the optimum reference value of the AGC is accurately estimated, which is confirmed in the computer simulation

Keywords

analogue-digital conversion; automatic gain control; code division multiple access; minimisation; mobile radio; parameter estimation; probability; quantisation (signal); spread spectrum communication; A/D conversion; ADC; AGC; DS-CDMA; PDF; SNR; computer simulation; despreading process; expectation/variance ratio; minimization; mobile radio; optimum reference value; probability density function; process gain estimation; quantization noise; saturation noise; wideband-CDMA system; Computer simulation; Equations; Gain; Multiaccess communication; Noise reduction; Power amplifiers; Quantization; Sampling methods; Signal analysis; Signal to noise ratio;

fLanguage

English

Publisher

ieee

Conference_Titel

Vehicular Technology Conference, 1999. VTC 1999 - Fall. IEEE VTS 50th

Conference_Location

Amsterdam

ISSN

1090-3038

Print_ISBN

0-7803-5435-4

Type

conf

DOI

10.1109/VETECF.1999.800127

Filename

800127