This study presents a simple technique, which is used to estimate both channel state and carrier frequency offset (CFO) in decode‐and‐forward relay systems, where coded orthogonal frequency division multiplexing is employed without cyclic prefix. On the basis of the least‐square criterion, we derive the estimate of CFO and channel with the aids of consecutive blocks of pilot symbols. The initially proposed estimation technique achieves a distinguished performance by using a two‐dimensional complete search approach; however, the computation becomes more and more intensive when the search granularity becomes finer and finer. For this reason, we further present an iterative approach as an alternative solution, which provides a performance comparable with that of the complete search method, while greatly reducing the implementation complexity. Besides, we also derive a closed‐form expression of the CFO estimate for the considered system, which allows us to avoid the exhaustive search during the estimation processing. Computer simulations have been conducted to verify the efficiency of the proposed schemes.

This paper presents an intelligent filter design method with a fixed-point digital signal processor (DSP) and illustrates its performance on the application of active noise cancellation (ANC) system. The proposed designing method uses magnitude and phase compensation techniques to eliminate the errors associated with the nonlinear distortion of analog devices in the application, and hence, to improve the ANC performance. The quantization and rounding errors associated with the fixed-point DSP are also compensated for. Several experiments verify the enhancement.

This paper proposes a simple diversity scheme that makes use of nonlinear block coding, symbol interleaving, and differential phase modulation. The resultant signaling mechanism merits intrinsic time diversity within each codeword, which is resistant to correlated fading. The maximum-likelihood noncoherent receiver which operates over correlated Rayleigh fading is developed. Exact and approximate upper bounds are derived to assess the codeword-error probability characteristics of the proposed system.

This paper proposes a simple diversity scheme which operates on the frequency-nonselective correlated Rayleigh fading channel. The proposed transmitter consists of a nonlinear block encoder, a symbol interleaver and a differential phase modulator. The resultant signaling mechanism merits intrinsic time diversity within each codeword, which is resistant, to rapid channel fading. The maximum-likelihood noncoherent receiver is developed to detect the received diversity signal codeword by codeword. A union-bound expression is derived to assess the codeword error probability characteristics of the proposed diversity scheme and particularly used as the code merit figure for searching for good codes. It is analytically shown that the diversity systems employing the searched short-blocklength codes can offer remarkable gains in error performance on the correlated Rayleigh channel.