For the power controlled DS-CDMA reverse link, two important issues must be addressed when using a Rake combiner with a limited path diversity order (defined as the number of resolved paths used for combining): the decrease in link capacity and the increase in peak transmit power. The peak transmit power is an important design parameter of transmit power amplifiers. In this paper, expressions for the achievable capacity and required peak transmit power under an multi-cell environment are developed. Based on the developed expressions, the relative capacity and required peak transmit power are evaluated theoretically and by Monte Carlo simulations under multipath Rayleigh fading environments with uniform and exponential power delay profiles. The effects of Rake based on maximal ratio combining (MRC) and selection combining (SC) are compared. The influence of the power delay profile shapes is also discussed.

This paper considers the evaluation of the acquisition performance for an access channel preamble based on the random access procedure of direct sequence code division multiple access (DS/CDMA) reverse link. The parallel acquisition technique that employs the single-dwell and multiple-dwell (double-dwell) detection schemes is investigated. The acquisition performance for two detection schemes is compared in terms of the acquisition probablity and the mean acquisition time. The parallel acquisition is done by a bank of N parallel I/Q noncoherent correlators. Expressions on the detection, false alarm, and miss probabilities of the single-dwell and multiple-dwell (double-dwell) detection schemes are derived for the multiple H1 cells and multipath Rayleigh fading channel. Comparing the single-dwell detection scheme with the multiple-dwell (double-dwell) detection scheme in the case of employing the parallel acquisition technique in the reverse link, the numerical results show that the single-dwell detection scheme provides a better performance.

The effect of intersymbol interference resulting from non-matched receiver filtering on the bit error rate (BER) performance of π/4-DQPSK systems recently adopted in the North American and Japanese digital cellular standards, is analyzed in Rayleigh fading. With a Gaussian or a Butterworth (of order N, 2N10) receiver filter, the BER performance is found to degrade by only a small fraction of a decibel from the performance with ideally matched receiver filters. A 4th-order Butterworth receiver filter leads to BER curves which almost coincide with those of the ideally matched filtering condition.