Blind Adaptive Equalizer Based on CMA and LMS Algorithm

• OKELLO James

  Faculty of Computers and Electronics Engineering, Kyushu Institute of Technology

• UEDA Kenji

  Faculty of Computers and Electronics Engineering, Kyushu Institute of Technology

• OCHI Hiroshi

  Faculty of Computers and Electronics Engineering, Kyushu Institute of Technology

Abstract

In this letter we verify that a blind adaptive algorithm operating at a low intermediate frequency (Low-IF) can be applied to a system where carrier phase synchronization has not been achieved. We consider a quadrature amplitude shift keyed (QPSK) signal as the transmitted signal, and assume that the orthogonal low intermediate sinusoidal frequency used to generate the transmitted signal is well known. The proposed algorithm combines two algorithms: Namely, the least mean square (LMS) algorithm which has a cost function with unique minimum, and the constant modulus algorithm (CMA), which was first proposed by Godard. By doing this and operating the equalizer at a rate greater than the symbol rate, we take advantage of the variable amplitude of the sub-carriers and the fast convergence of LMS algorithm, so as to achieve a faster convergence speed. When the computer simulation results of the proposed algorithm are compared with the constant modulus algorithm (CMA) and the modified CMA (MCMA), we observed that the proposed algorithm exhibited a faster convergence speed.

Journal

• IEICE transactions on communications

  IEICE transactions on communications 87 (4), 1012-1015, 2004-04-01

  The Institute of Electronics, Information and Communication Engineers

Keywords

• equalizer
• blind algorithm
• CMA
• LMS

Details

• CRID: 1570291227388129024
• NII Article ID: 110003222318
• NII Book ID: AA10826261
• ISSN: 09168516
• Text Lang: en
• Data Source:
  • CiNii Articles