In this paper we investigate performance of turbo codes with Max-Log-MAP decoding on slow, flat Rayleigh fading channels. In order to simplify decoding algorithm implementation for a fading channel, the Gaussian distribution is applied to a channel metric. By means of computer simulations, we estimate BER of turbo codes on fully-interleaved and correlated channels with ideal CSI and without CSI...

Wireless communication at near-capacity transmission throughputs is facilitated by employing sophisticated Error Correction Codes (ECCs), such as turbo codes. However, real time communication at high transmission throughputs is only possible if the challenge of implementing turbo decoders having equally high processing throughputs can be overcome. This motivates the implementation of turbo deco...

—It is known that one of the essential building blocks of distributed turbo codes is the interleaver and its design uses random, semi-random (S-Random) and deterministic permutations. In this paper, a new modified matched S-random interleaver for turbo code is proposed. Then we extend the effect of this new interleaver to the relay channel to evaluate the interleaving gain in two different dis...

We construct new families of error-correcting codes based on Gallager’s low-density parity-check codes, which we call irregular codes. When decoded using belief propagation, our codes can correct more errors than previously known low-density parity-check codes. For example, for rate 1/4 codes on 16,000 bits over a binary symmetric channel, previous low-density parity-check codes can correct up ...

In this paper, we propose the space-time turbo codes designed over integer ring for BPSK and QPSK modulation. The proposed spacetime turbo codes addeve the full spatial diversity and can be decoded using the iterative binary soft-input sofl-output (SISO) algorithm. The BPSK/QPSK binary rank criterion is used to find the interleavers which guarantee the full spatial diversity. It is shown that t...

The Gaussian approximation has been used to study iterative decoding algorithms of graph-based codes like turbo codes [7, 8] and low-density parity check (LDPC) codes [6]. In this work, the Gaussian approximation is used to describe the turbo decoding algorithm (TDA) as an elegant discrete dynamical system and explicit iterative equations for the evolution of the BER with the decoder phases of ...

List decoding of turbo codes is analyzed under the assumption of a maximum-likelihood (ML) list decoder. It is shown that large asymptotic gains can be achieved on both the additive white Gaussian noise (AWGN) and fully interleaved flat Rayleigh-fading channels. It is also shown that the relative asymptotic gains for turbo codes are larger than those for convolutional codes. Finally, a practica...

Turbo-codes provide communications near capacity when very large interleavers (and thus codeword lengths) are used. However, many military communication systems require packet lengths that are too short to exploit the full capability of these codes. We have previously shown that a rectangular parity-check code can be used as an outer code with a turbo code as an inner code in a serial concatena...

The problem of performing iterative detection (ID)—a technique originally introduced for the decoding of turbo codes—for systems having parametric uncertainty has received relatively little attention in the open literature. In this paper, the problem of adaptive ID (AID) for serial and parallel concatenated convolutional codes (SCCC’s and PCCC’s or turbo codes) in the presence of carrier-phase ...

In this paper, we study the convergence properties of low-complexity (2and 4-state) multiple turbo codes on an AWGN channel. An analytical approach to determine the extrinsic information transfer characteristics of 2-state codes is presented. This is then used to compute the convergence thresholds of several rate 1/2, 2-state multiple turbo codes. The convergence thresholds predicted by the ana...