In this work various channel estimation algorithms of the Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MIMO-OFDM) are studied. The result of Linear Minimum Mean Square Error (LMMSE) channel estimation algorithm was compared with the Least Squares (LS) and Minimum Mean Square Error (MMSE) for both OFDM and MIMO-O...

This paper investigates an adaptive space-time equalisation (STE) assisted multiuser detection scheme for multiple-antenna aided multiuser systems. A minimum bit error rate (MBER) design is compared with the standard minimum mean square error (MMSE) design. It is shown that the MBER design provides significant performance enhancement, in terms of achievable system bit error rate, over the MMSE ...

Novel coherent detectors for DQPSK and-DQPSK on Rayleigh fading channels are presented. The detectors are based on decision feedback and minimum mean square error (MMSE) channel estimation. The proposed detectors may be used in both single carrier and multicarrier systems. Analytical results in form of expressions for channel estimation error variance and bit error probability, both with and wi...

This paper proposes low-complexity preand postfrequency domain equalization and frequency diversity combining methods for block transmission schemes with cyclic prefix. In the proposed methods, the equalization and diversity combining are performed simultaneously in discrete frequency domain. The weights for the proposed equalizer and combiner are derived based on zero-forcing and minimummean-s...

In an amplify-and-forward cooperative network, a closed-form expression of the a priori distribution of the complex-valued gain of the global relay channel is intractable, so that a priori information is often not exploited for estimating this gain. Here, we present two iterative channel gain and noise variance estimation algorithms that make use of a priori channel information and exploit the ...

The minimum mean-square error (MMSE) and minimum error entropy (MEE) are two important criteria in the estimation related problems. The MMSE can be viewed as a robust MEE criterion in the minimax sense, as its minimization is equivalent to minimizing an upper bound (the maximum value) of the error entropy. This note gives a new and more meaningful interpretation on the robustness of MMSE for pr...

This study mainly focuses on multiuser detection in tracking and data relay satellite (TDRS) system forward link. Minimum mean square error (MMSE) is a low complexity multiuser detection method, but MMSE detector cannot achieve satisfactory bit error ratio and near-far resistance, whereas artificial fish swarm algorithm (AFSA) is expert in optimization and it can realize the global convergence ...

This paper focuses on the equalization of block transmissions with zero pad (ZP). If the channel impulse response length does not exceed the ZP length, it is possible to construct zero-forcing equalizers (ZFEs). Improved performance may be achieved using a minimummean squared error (MMSE) equalizer. However, these equalizers are computationally intensive when a time-domain implementation is use...

The adaptive algorithm has been widely used in the digital signal processing like channel estimation, channel equalization, echo cancellation, and so on. One of the most important adaptive algorithms is the RLS algorithm. We present in this paper n multiple objective optimization approach to fast blind channel equalization. By investigating first the performance (mean-square error) of the stand...

Integrating the strengths of multicarrier (MC) modulation and code division multiple access (CDMA), MC-CDMA systems are of great interest for future broadband transmissions. This paper considers the problem of channel identification and signal combining/detection schemes for MC-CDMA systems equipped with multiple transmit antennas and space-time (ST) coding. In particular, a subspace-based blin...