"Turbo DPSK": iterative differential PSK demodulation and channel decoding

The principle of coding in the signal space follows directly from Shannon's analysis of waveform Gaussian channels subject to an input constraint. The early design of communication systems focused separately on modulation, namely signal design and detection, and error correcting codes, which deal with errors introduced at the demodulator of the underlying waveform channel. The correct perspective of signal-space coding, although never out of sight of information theorists, was brought back into the focus of coding theorists and system designers by Imai's and Ungerböck's pioneering works on coded modulation. More recently, powerful families of binary codes with a good tradeoff between performance and decoding complexity have been (re-)discovered. Bit-Interleaved Coded Modulation (BICM) is a pragmatic approach combining the best out of both worlds: it takes advantage of the signal-space coding perspective, whilst allowing for the use of powerful families of binary codes with virtually any modulation format. BICM avoids the need for the complicated and somewhat less flexible design typical of coded modulation. As a matter of fact, most of today's systems that achieve high spectral efficiency such as DSL, Wireless LANs, WiMax and evolutions thereof, as well as systems based on low spectral efficiency orthogonal modulation, feature BICM, making BICM the de-facto general coding technique for waveform channels.The theoretical characterization of BICM is at the basis of efficient coding design techniques and also of improved BICM decoders, e.g., those based on the belief propagation iterative algorithm and approximations thereof. In this text, we review the theoretical foundations of BICM under the unified framework of error exponents for mismatched decoding. This framework allows an accurate analysis without any particular assumptions on the length of the interleaver or independence between the multiple bits in a symbol. We further consider the sensitivity of the BICM capacity with respect to the signal-to-noise ratio (SNR), and obtain a wideband regime (or low-SNR regime) characterization. We review efficient tools for the error probability analysis of BICM that go beyond the standard approach of considering infinite interleaving and take into consideration the dependency of the coded bit observations introduced by the modulation. We also present bounds that improve upon the union bound in the region beyond the cutoff rate, and are essential to characterize the performance of modern randomlike codes used in concatenation with BICM. Finally, we turn our attention to BICM with iterative decoding, we review extrinsic information transfer charts, the area theorem and code design via curve fitting. We conclude with an overview of some applications of BICM beyond the classical coherent Gaussian channel. List of Abbreviations, Acronyms, and SymbolsRatio between average bit energy and noise spectral densityReliability function at rate R E bicm 0 (ρ, s) BICM random coding exponent E cm 0 (ρ) CM random coding exponent ...

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“…Common choices for practical implementations in this case include differential PSK or block-differential PSK [53,88,89,90,91].…”

Section: Concluding Remarks and Related Workmentioning

confidence: 99%

Bit-Interleaved Coded Modulation

Fàbregas

Martinez

Caire

2007

FNT in Communications and Information Theory

186

165

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“…However, there are other methods of rendering the IR duration infinite. For example, in [12], it has been argued that turbo-detected digital phase-shift keying (PSK) has the potential of outperforming coherent PSK, although this requires a number of iterative detection steps. We will demonstrate that the precoder potentially provides a more flexible method of controlling the spread of the extrinsic information using different feedback polynomials and various precoder memory sizes with the aid of EXIT chart analysis [13].…”

Section: Introductionmentioning

confidence: 99%

Precoded Sphere-Packing-Aided Bit-Interleaved Differential Space-Time Coded Modulation Using Iterative Decoding

Alamri

et al. 2008

IEEE Trans. Veh. Technol.

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“…Some of the methods use an outer encoder (convolutional, LDPC or turbo code) followed by a modulation encoder, with iterative decoding between them on the receiver side [1], [5], [7], [8], [9], [12], [13]. Typically the outer and modulation encoders are separated by an interleaver.…”

Section: Introductionmentioning

confidence: 99%

Joint Carrier Phase Estimation and Turbo Decoding Using Bit Carrier Phase APP Decoder

Saroka

Raphaeli

2007

IEEE Trans. Commun.

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-In this paper we present an algorithm for joint carrier phase estimation and turbo decoding for the case of rapidly varying carrier phase during the transmitted block. The proposed algorithm shows improved performance over previously proposed communication schemes, both coherent and non-coherent, for channels with Additive White Gaussian Noise (AWGN) and high carrier phase noise. The novel algorithm utilizes a modified "two dimensional" Bit-Carrierphase A Posteriori Probability (BCAPP) decoder containing additional states representing the received carrier phase. The BCAPP decoder calculates two extrinsic metrics; one representing the bit soft value and the other representing the received carrier phase Probability Density Function (PDF) approximation. A modified structure of the turbo code iterations is suggested, implementing separate propagation of the two metrics between the BCAPP decoders. Most known methods to combat very high phase noise in the channel at low signal to noise ratio are based on non-coherent demodulation. Such reception schemes are designed for the worst-case phase noise and suffer high degradation for any level of phase noise. In our scheme, together with improved performance in high phase noise, the degradation decreases with the actual channel phase noise level. We show the robustness against phase noise model mismatch.

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"Turbo DPSK": iterative differential PSK demodulation and channel decoding

Cited by 196 publications

References 35 publications

Bit-Interleaved Coded Modulation

Bit-Interleaved Coded Modulation

Precoded Sphere-Packing-Aided Bit-Interleaved Differential Space-Time Coded Modulation Using Iterative Decoding

Joint Carrier Phase Estimation and Turbo Decoding Using Bit Carrier Phase APP Decoder

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