Performance of the turbo hybrid automatic repeat request system type II

In many applications it is necessary to maintain an error-free transmission of data. For low-quality time varying channels, channel coding alone often cannot ensure this and the employment of automatic repeat requests (ARQ) is unavoidable. For achieving high efficiency, a combination of both channel coding and ARQ, also referred to as hybrid ARQ (HARQ), is preferable. Using turbo codes (TC)-the most powerful of known error-correcting codes-in HARQ transmission schemes results in very efficient transmission systems, which maintain a high throughput over additive white Gaussian noise (AWGN) channels even for signal-to-noise ratios (SNR) as low as E/sub s//N/sub 0/=-2 dB. The aim of this article is to construct a turbo hybrid ARQ (THAQ) system of type II, which guarantees a high throughput at extremely low SNRs, where other known THARQ systems suffer from rapid throughput degradation.