Blind estimation of space?time coded systems using the finite alphabet?constant modulus algorithm

Space-time coding introduces spatial and temporal correlations into signals transmitted from multiple antennas in order to provide diversity and coding gain at the receiver. In the field of blindly estimating space-time coded signals impinging on an antenna array, an effective scheme for jointly exploring the constant modulus (CM) and the finite alphabet (FA) constraints is presented. The CM constraints are explored algebraically, whereas the FA constraints are explored via an iterative algorithm considering the constraints imposed by the space-time coded signals. This leads to our novel FACM algorithm that offers a wide range of trade-offs between performance and complexity while it lends itself to an amenable (step-by-step) algorithmic implementation as well as an amenable algorithmic complexity     

Hybrid channel coding scheme for blind space-time coded MIMO systems

This letter proposes a hybrid use of channel codes in wireless systems employing multiple transmit/multiple receive antennas. We concatenate space-time codes (STCs) serially with low-density parity check (LDPC) codes and turbo codes. We show that by using these powerful coding schemes effectively, substantial performance improvements can be achieved. This is motivated by the need for a scheme that gives promising performance even when no training is available. The proposed scheme results in a desirable trade-off between performance and complexity.     

Regularised analytical constant modulus algorithm for space–time coded systems

Space–time coding is an effective approach to increase the data rate and capacity of a wireless communication system that employs multiple transmit and multiple receive antennas. It involves coding techniques that are designed for multiple transmit antennas. We apply the analytical constant modulus algorithm (ACMA) for blind channel estimation (no use of training sequences) of space–time coded systems and explore the constant modulus (CM) constraints of the transmitted space–time codes (STCs). A regularised scheme that gives good performance in Gaussian and non-Gaussian noise environments is proposed. Computer simulation results in both single-user and multiuser cases show the improvement in error performance.