Low complexity design of space-time convolutional codes with high spectral efficiencies

ABSTRACT

Space time convolutional codes (STCCs) are an effective way to combine transmit diversity with coding. The computational complexity of designing STCCs generally increases exponentially with the constellation size of the transmitted symbols. In this paper, we first present an innovative approach to design STCCs with high spectral efficiencies by utilizing QPSK STCCs as component codes and consequently. Unlike existing techniques, the search space does not grow exponentially with the constellation size. Then, we present two approaches to reduce the computational complexity of our proposed scheme. This scheme is applicable to cases with any number of transmit antennas without any requirement to change the encoder design. Simulation results evaluate the performance of our approach for the case of two transmit antennas and several different number of receive antennas, a spectral efficiency of 4 bits/s/Hz, and slow Rayleigh fading channels.

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INDEX TERMS

Primary Classification:
  B. Hardware
  B.4 INPUT/OUTPUT AND DATA COMMUNICATIONS
      B.4.1 Data Communications Devices

General Terms:
Algorithms, Design

Keywords:
MIMO systems, space-time codes