Effects of Nakagami-Fading Parameters and Power Control Error on Performance of DS-CDMA Cellular Systems with Adaptive Beamforming

  • Authors:

  • Mohamad Dosaranian-Moghadam;Hamidreza Bakhshi;Gholamreza Dadashzadeh

  • Affiliations:

  • Department of Electrical Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran;Department of Electrical Engineering, University of Shahed, Tehran, Iran;Department of Electrical Engineering, University of Shahed, Tehran, Iran

  • Venue:
  • Wireless Personal Communications: An International Journal
  • Year:
  • 2013

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Abstract

It is well known that power control error (PCE) is a critical issue in CDMA cellular systems. In this paper, the bit error rate (BER) of a direct sequence-code division multiple access (DS-CDMA) receiver with imperfect power control, adaptive beamforming, and voice activity is derived in frequency-selective Nakagami fading channels. We discuss the effects of PCE, Nakagami-m fading parameter, and channel's multipath intensity profile as average signal strength and rate of average power decay and their effects on the BER performance of DS-CDMA cellular systems. In this paper, the RAKE receiver consists of three stages. In the first stage, with conjugate gradient adaptive beamforming algorithm, the desired users' signal in an arbitrary path is passed and the inter-path interference is canceled in other paths in each RAKE finger. Also in this stage, the multiple access interference (MAI) from other users is reduced. Thus, the matched filter (MF) can be used for the MAI reduction in each RAKE finger in the second stage. In the third stage, the output signals from the MFs are combined according to the conventional maximal ratio combining principle and then are fed into the decision circuit for the desired user. How the Nakagami fading parameters, power control imperfections, or the number of resolvable paths affect the reverse link capacity of the system is discussed in detail. Analytical and simulation results are also given for systems with different processing gains and number of BSs in the cell-selection process with various Nakagami fading parameters.