Abstract
A new scheme of concatenating the block turbo code (BTC) with the space-time block code (STBC) for an OFDM system in dispersive fading channels is investigated in this paper. The good error correcting capability of BTC and the large diversity gain characteristics of STBC can be achieved simultaneously. The resulting receiver outperforms the iterative convolutional Turbo receiver with maximuma posteriori probability expectation-maximization (MAP-EM) algorithm. Because of its ability to perform the encoding and decoding processes in parallel, the proposed system is easy to implement in real time.
Highlights
In wireless communications, frequency-selective fading in unknown dispersive channels is a dominant problem in high data rate transmission
Most of the work on turbo codes has essentially been focused on convolutional turbo codes (CTC), while much less effort has been spent on block turbo codes (BTC)
The results for the iterative turbo receiver with maximum a posteriori probability expectation-maximization (MAP-EM) algorithm in the space-time block coding (STBC)-Orthogonal frequency division multiplexing (OFDM) system are given for different models and different Doppler frequencies in Figures 6, 7, 8 and 9 where the performance of the concatenated STBC-BTC system in an AWGN channel after four iterations [15] is shown as a reference
Summary
Frequency-selective fading in unknown dispersive channels is a dominant problem in high data rate transmission. The discussion in [6] points out that such BTC codes have instituted the trellis structure, which can lead to a high complexity because the number of states in the trellis of a block code increases exponentially with the number of redundant bits. If one more check bit is padded to each elementary block code, the minimum distance is increased to 16 for the BTC at the cost of a slightly lower code rate Another attractive feature of this BTC is that the decoding speed can be increased by employing a bank of parallel elementary decoders for the rows and columns of the product code since they are independent but with the same structure. We propose here to investigate by means of simulations the receiver performance of an STBC-OFDM system in a dispersive fading channel where b(t) BTC encoder d(t) BTC decoder.
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