Turbo codes achieve performance near the Shannon limit. Standard sequential VLSI implementation of turbo decoding requires many iterations and incurs a long latency, which cannot be tolerated in some applications. A novel parallel VLSI architecture for turbo decoding is described, comprising multiple SISO elements, operating jointly on one turbo coded block, and a new parallel interleaver. Late...

The performance and design of turbo codes using coherent BPSK signaling on the Rayleigh fading channel is considered. In low signal-to-noise regions, performance analysis uses simulations of typical turbo coding systems. For higher signalto-noise regions beyond simulation capabilities, an average upper bound is used in which the average is over all possible interleaving schemes. Fully interleav...

Peter C. Massey and Daniel J. Costello, Jr. Dept. of Ele . Engr. University of Notre Dame Notre Dame, IN 46556 Phone: 219-631-5483, Fax: 219-631-4393 E-mail: pmassey nd.edu ostello.2 nd.edu Abstra t: Several new lasses of asymmetri turbo odes are introdu ed whi h o er improved performan e ompared to the original turbo ode over the entire range of signal-to-noise ratios. The new turbo odes make ...

| We study the performance of turbo codes for magnetic recording channels using realistic channel models. Our main objective is to provide a benchmark for the future studies on the subject. We examine a variety of schemes including the use of parallel concatenated turbo codes with and without turbo equalization and convolutional codes with an interleaver (can be regarded as a serial concatenati...

Instead of a random interleaver, an algebraic interleaver interconnecting two simple convolutional codes with feedback encoders forms an algebraic quasi-cyclic code. An (nC , k) convolutional code in tailbiting form becomes a quasi-cyclic (QC) linear code of length LnC for some L = Mn. Interleavers with a period M connect two such codes to produce a QC turbo code. The QC turbo codes check equat...

Turbo decoding is based on the concept of maximum likelihood decision on blocks of data. The decision on a bit affects the decoding of subsequent bits. Fading is a type of corruption whose effect can be extended over a period of multiple bits, resulting in significant performance degradation for turbo code. In this paper, a Markov process is utilized to model a fading channel, and bit error rat...

In this study, turbo codes were investigated in a slow frequency-hopped binary frequency shift keying spread spectrum (FH/BFSK-SS) system with partial band jamming and full-band thermal noise. A soft decision decoding metric which includes automatic gain control (AGC) is proposed for turbo code decoding with a non-coherent square law receiver of FH/BFSK. The study focused on the performance com...

—This letter is concerned with a family of modified turbo-type codes, referred to as turbo-SPC (single parity check) codes. A technique based on the SPC code is introduced to replace puncturing for rate adjustment. A noticeable feature of the proposed scheme is the significantly reduced decoding complexity compared with the standard punctured turbo code. The cost reduction factor becomes more n...

Despite the considerable research effort towards the analysis and understanding of the nature of turbo decoding, a clear identification of the underlying optimization problem the turbo decoder attempts to solve is still missing. In this paper, we link the turbo decoding algorithm to maximum likelihood (ML) sequence detection by demonstrating how the turbo decoder can be systematically derived s...

We study the use of turbo-coded modulation for wireless communication systems with multiple transmit and receive antennas over block Rayleigh fading channels. We describe an effective way of applying turbo-coded modulation as an alternative to the current space–time codes with appropriate interleaving. We study the performance with the standard iterative turbo decoding algorithm, as well as the...