Turbo codes for incoherent M-ary orthogonal signaling

Chayat, N.

doi:10.1109/eeis.1996.567018

Cited by 7 publications

(3 citation statements)

References 4 publications

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“…Typically the outer and modulation encoders are separated by an interleaver. Most modulation encoders use differential encoding (DE) or orthogonal waveforms [13] that assist non-coherent detection. Such modulations tend to decrease the code performance relative to Binary Phase Shift Keying (BPSK) for the same bandwidth expansion.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Introductionmentioning

confidence: 99%

“…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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“…Thus, the detail study of the performance of this system is important to provide some insight on the design of combined turbo-code and orthogonal modulation and its applicability to CDMA wireless communication systems. In [6], a system consisting of a rate l/n turbo-code combined with a 2n-ary orthogonal signaling has been introduced. In this paper, we examine a system employing a rate 1/3 turbocode combined with M-ary orthogonal signaling in general.…”

Section: Introductionmentioning

confidence: 99%

Combined turbo-code and modulation for CDMA wireless communications

Mohammadi

Zhuang²

VTC '98. 48th IEEE Vehicular Technology Conference. Pathway to Global Wireless Revolution (Cat. No.98CH36151)

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This paper investigates a system of combined turbo-code and M-ary orthogonal signaling for CDMA wireless communications. The performance of the system is studied over AWGN channel with coherent and noncoherent detection for short frame lengths, with emphasis on the effect of noise correlation between the coded bits. It is shown that eliminating this correlation is important in improving the transmission performance of the system. When a 6CHadamard signaling is employed, the performance of the system is improved by approximately 0.8 dB at a signal-to-noise ratio (SNR) per information bit of 4 dB, and the improvement increases as the SNR increases. It is also shown that for the bit error rate (BER) of interest in voice communication systems, 8-Hadamard mapping performs almost as well as 64-Hadamard mapping, with less complexity and delay.

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The capacity of orthogonal and bi-orthogonal codes on the Gaussian channel

MacMullan

Collins

1998

IEEE Trans. Inform. Theory

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This correspondence analyzes the performance of concatenated coding systems and modulation schemes operating over the additive white Gaussian noise (AWGN) channel by examining the loss of capacity resulting from each of the processing steps. The techniques described in this correspondence allow the separate evaluation of codes and decoders and thus the identification of where loss of capacity occurs. Knowledge of this capacity loss is very useful for the overall design of a communications system, e.g., for evaluating the benefits of inner decoders that produce information beyond the maximum-likelihood (ML) estimate. The first two sections of this correspondence provide a general technique for calculating the composite capacity of an orthogonal or a bi-orthogonal code and the AWGN channel in isolation. The later sections examine the composite capacities of an orthogonal or a bi-orthogonal code, the AWGN channel, and various inner decoders including the decoder estimating the bit-by-bit probability of a one, as is used in turbo-codes. The calculations in these examples show that the ML decoder introduces a large loss in capacity. Much of this capacity loss can be regained by using only slightly more complex inner decoders, e.g., a detector for M-ary frequency-shift keying (MFSK) that puts out the two most likely frequencies and the probability the ML estimate is correct produces significantly less degradation than one that puts out only the most likely frequency.

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Turbo codes for incoherent M-ary orthogonal signaling

Cited by 7 publications

References 4 publications

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

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

Combined turbo-code and modulation for CDMA wireless communications

The capacity of orthogonal and bi-orthogonal codes on the Gaussian channel

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