Comparison of optimum and sub-optimum turbo decoding schemes in 3rd generation cdma2000 mobile system

Luukkanen, P.; Zhang, Ping

doi:10.1109/wcnc.1999.797863

Cited by 3 publications

(3 citation statements)

References 4 publications

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“…In order to have a robust design for all channel situations and to transform this signal with wide dynamic range to a finite precision data, the output of the RAKE receiver must be scaled. Different studies have been conducted on fixed point realization, signal quantization and scaling and numerical issues of turbo codes [5][6][7][8]. In this section, we compare performance and complexity of different scaling schemes for the 3GPP system.…”

Section: Signal Scaling and Quantizationmentioning

confidence: 99%

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Implementation Issues in Turbo Decoding for 3GPP FDD Receiver

Hagh

Salehi

Sharma

et al. 2006

Wireless Pers Commun

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In the Frequency Division Duplex (FDD) mode of the Third Generation Partnership Project (3GPP) standard, implementation of the turbo decoder, especially for the mobile equipments, faces design decisions related to computational complexity, power efficiency, and memory requirements. In this paper we compare different approaches of low complexity implementation of the turbo decoder, with emphasis on the issues of signal scaling and quantization, the sliding window operation for memory size reduction and the iteration stopping algorithms.The demodulated signal at the output of the RAKE receiver may have a wide dynamic range and it may require many bits of precision. In order to overcome the numerical precision problem and to prevent Log Likelihood ratio (LLR) metric overflow, a scaling algorithm must be used. Our simulation results indicate that the Average Absolute (AA) algorithm using dynamic scaling outperforms other scaling schemes and it is less sensitive to the channel conditions.One of the major challenges in the implementation of a practical turbo decoder is optimization of memory requirements. In this paper we evaluate the performance of the sliding window algorithm using different main and guard window sizes. We show that the bit and block error rate performance of the sliding window scheme mainly depend on the guard window size rather than the main window size. The simulation results indicate that small guard window sizes can significantly decrease the iteration gain for large frames in fast fading channels.Iteration stopping algorithms reduce the power consumption and the latency of the decoder and help to dedicate more resources to other functions of the receiver. The block error distribution in the fading channels makes it even more essential to use an iteration stopping rule. Our simulations conclude that a rule called the minimum absolute value appears to be a very effective, low complexity and robust algorithm.

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Section: Signal Scaling and Quantizationmentioning

confidence: 99%

“…In 3GPP, the entire transport block is used to calculate the CRC parity bits for each transport block. The parity bits are generated by the following cyclic generator polynomials: g CRC16 (D) = D 16 + D 12 + D 5 + 1 (8) and the encoding is performed in a systematic form, which means that in GF(2), the polynomial:…”

Section: Crc Algorithmmentioning

confidence: 99%

Implementation Issues in Turbo Decoding for 3GPP FDD Receiver

Hagh

Salehi

Sharma

et al. 2006

Wireless Pers Commun

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“…Compared to Max-Log-MAP, SOVA also deals with only two paths: one is the ML path, but the other is not necessarily the same as that considered in Max-Log-MAP, the best competing path. Thus, SOVA will lose approximately another 0.5 dB in performance compared with Max-Log-MAP, but with a much lower complexity [17]. Again, it is shown in [12] that some modifications can be made on SOVA to make it equivalent to Max-Log-MAP.…”

Section: Turbo Decoding For Coded Dmt Systemmentioning

confidence: 99%

Turbo multiuser detection for coded DMT VDSL systems

Dai

Poor

2002

IEEE J. Select. Areas Commun.

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In recent years, iterative processing techniques with soft-in/soft-out (SISO) components have received considerable attention. Such techniques, based on the so-called turbo principle, are exemplified through turbo decoding, turbo equalization and turbo multiuser detection. In this paper, turbo multiuser detection is applied to a discrete multitone (DMT) very-high-rate digital subscriber line (VDSL) system to combat crosstalk signals and to obtain substantial coding gain. The proposed iterative DMT receiver is shown to achieve an overall 7.0 dB gain over the uncoded optimum receiver at a bit error rate of 7 10 − for a channel with severe intersymbol interference and additive white Gaussian noise and with one dominant crosstalk signal. Impulse noise is detrimental to the proposed scheme but can be overcome through erasure decoding techniques, as is shown by example.

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Analysis of an efficient real-time generation of E/sub S//N/sub 0/ estimates for M-PSK signals

Linn

CCECE 2003 - Canadian Conference on Electrical and Computer Engineering. Toward a Caring and Humane Technology (Cat. No.03CH374

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Comparison of optimum and sub-optimum turbo decoding schemes in 3rd generation cdma2000 mobile system

Cited by 3 publications

References 4 publications

Implementation Issues in Turbo Decoding for 3GPP FDD Receiver

Implementation Issues in Turbo Decoding for 3GPP FDD Receiver

Turbo multiuser detection for coded DMT VDSL systems

Analysis of an efficient real-time generation of E/sub S//N/sub 0/ estimates for M-PSK signals

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