RLS channel estimation with adaptive forgetting factor for DS-CDMA frequency-domain equalization

Yohei Kojima, Hiromichi Tomeba, Kazuaki Takeda, Fumiyuki Adachi

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Frequency-domain equalization (FDE) based on the minimum mean square error (MMSE) criterion can increase the downlink bit error rate (BER) performance of DS-CDMA beyond that possible with conventional rake combining in a frequency-selective fading channel. FDE requires accurate channel estimation. Recently, we proposed a pilot-assisted channel estimation (CE) based on the MMSE criterion. Using MSE-CE, the channel estimation accuracy is almost insensitive to the pilot chip sequence, and a good BER performance is achieved. In this paper, we propose a channel estimation scheme using one-tap recursive least square (RLS) algorithm, where the forgetting factor is adapted to the changing channel condition by the least mean square (LMS) algorithm, for DS-CDMA with FDE. We evaluate the BER performance using RLS-CE with adaptive forgetting factor in a frequency-selective fast Rayleigh fading channel by computer simulation.

Original languageEnglish
Pages (from-to)1457-1465
Number of pages9
JournalIEICE Transactions on Communications
Issue number5
Publication statusPublished - 2009 May


  • Channel estimation
  • Frequency-domain equalization
  • RLS algorithm

ASJC Scopus subject areas

  • Software
  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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