Performance Degradation in Pre-rake Frequency-division Duplex/ Direct Sequence-code Division Multiple Access Systems

  • C. Subhas Sree Vidyanikethan Engineering College, Tirupati
  • K. Rama Naidu JNTU College of Engineering, Anantapur
  • Y. Venkatarami Reddy Andhra Pradesh Public Service Commission, Hyderabad
Keywords: Direct sequence-code division multiple access, DS-CDMA, rake receiver, pre-rake, inter-symbol interference, frequency-division duplex, FDD, channel prediction

Abstract

The transmitter-based pre-rake diversity combining technique reduces the complexity, size and cost of the mobile unit (MU), while achieving the same inter symbol interference (ISI) mitigation effects of rake receiver for direct sequence-code division multiple access (DS-CDMA) systems. The technique is based on preprocessing of transmitted signal relying on knowledge of the channel state information (CSI) before transmission. In most of the previous works, this a priori information is either assumed or estimated for the uplink and the same is applied to the downlink in time division duplex (TDD) systems due to channel reciprocity. In this paper, a method for channel prediction to evaluate the pre-rake system using binary phaseshift keying (BPSK) modulation in frequency-division duplex (FDD) through analytical and computer simulations for DS-CDMA downlink has been proposed. The performance of the system was also evaluated under ideal and predicted channel conditions using different spreading codes. The findings will have widespread applications in defence communication equipment.

Defence Science Journal, 2010, 60(3), pp.282-289, DOI:http://dx.doi.org/10.14429/dsj.60.355

Author Biographies

C. Subhas, Sree Vidyanikethan Engineering College, Tirupati
Pursuing PhD in wireless communications at JNT University, Anantapur. His areas of research are wireless communications and signal processing.
K. Rama Naidu, JNTU College of Engineering, Anantapur
Head, Electronics and Communication Engineering Department, JNTU College of Engineering, Anantapur.
Y. Venkatarami Reddy, Andhra Pradesh Public Service Commission, Hyderabad
Chairman, Andhra Pradesh Public Service Commission, Hyderabad,
Published
2010-04-21
How to Cite
Subhas, C., Naidu, K., & Reddy, Y. (2010). Performance Degradation in Pre-rake Frequency-division Duplex/ Direct Sequence-code Division Multiple Access Systems. Defence Science Journal, 60(3), 282-289. https://doi.org/10.14429/dsj.60.355
Section
Review Papers