Firing the genie: Two-phase short-blocklength convolutional coding with feedback

Williamson, Adam R.; Chen, Tsung‐Yi; Wesel, Richard D.

doi:10.1109/ita.2013.6502986

Cited by 4 publications

(5 citation statements)

References 16 publications

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“…This is in contrast to informationfeedback VLF codes, which allow the transmitter to adapt its transmission based on information about the previously received symbols. See, e.g., [9]- [11], for recent investigations of information feedback at short blocklengths. Our work is the first to specifically address the question of how closely existing coding techniques using feedback (as opposed to theoretical constructs such as random coding) can approach capacity as a function of the average blocklength, without a special noiseless transmission or a genie informing the receiver when it has correctly decoded.…”

Section: Introductionmentioning

confidence: 99%

Variable-Length Convolutional Coding for Short Blocklengths With Decision Feedback

Williamson

Chen

Wesel

2015

IEEE Trans. Commun.

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Abstract-This paper presents a variable-length decisionfeedback coding scheme that achieves high rates at short blocklengths. This scheme uses the Reliability-Output Viterbi Algorithm (ROVA) to determine when the receiver's decoding estimate satisfies a given error constraint. We evaluate the performance of both terminated and tail-biting convolutional codes at average blocklengths less than 300 symbols, using the ROVA and tailbiting ROVA, respectively. Comparing with recent results from finite-blocklength information theory, simulations for both the BSC and the AWGN channel show that the reliability-based decision-feedback scheme can surpass the random-coding lower bound on throughput for feedback codes at some blocklengths less than 100 symbols. This is true both when decoding after every symbol is permitted, and when decoding is limited to a small number of increments. Finally, the performance of the reliability-based stopping rule with the ROVA is compared to retransmission decisions based on CRCs. For short blocklengths where the latency overhead of the CRC bits is severe, the ROVAbased approach delivers superior rates.

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Section: Introductionmentioning

confidence: 99%

Variable-Length Convolutional Coding for Short Blocklengths With Decision Feedback

Williamson

Chen

Wesel

2015

IEEE Trans. Commun.

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“…Now we consider the two-phase VLF model in which the transmitter (source) uses the primary communication channel to confirm whether the receiver (destination) has decoded to the correct codeword. As in [37], the two-phase incremental redundancy scheme has a communication phase followed by a confirmation phase. Fig.…”

Section: Two-phase Vlfmentioning

confidence: 99%

Optimizing Transmission Lengths for Limited Feedback With Nonbinary LDPC Examples

Vakilinia

Ranganathan

Wesel

2016

IEEE Trans. Commun.

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This paper presents a general approach for optimizing the number of symbols in increments (packets of incremental redundancy) in a feedback communication system with a limited number of increments. This approach is based on a tight normal approximation on the rate for successful decoding. Applying this approach to a variety of feedback systems using non-binary (NB) low-density parity-check (LDPC) codes shows that greater than 90% of capacity can be achieved with average blocklengths fewer than 500 transmitted bits. One result is that the performance with ten increments closely approaches the performance with an infinite number of increments. The paper focuses on binaryinput additive-white Gaussian noise (BI-AWGN) channels but also demonstrates that the normal approximation works well on examples of fading channels as well as high-SNR AWGN channels that require larger QAM constellations. The paper explores both variable-length feedback codes with termination (VLFT) and the more practical variable length feedback (VLF) codes without termination that require no assumption of noiseless transmitter confirmation. For VLF we consider both a two-phase scheme and CRC-based scheme.

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“…As shown by the VLFT converse, R RCSP , and even the convolutional VLFT simulation, NTC allows rates higher than the original channel capacity when the average blocklength is very small. As discussed in [6], [12], the benefit of NTC (and the overhead associated with replacing NTC with regular channel uses that reliably inform the receiver of successful decoding) becomes smaller for larger blocklengths. This is the primary motivation to consider blocklengths that are several hundred bits, which is still short enough that feedback provides a significant throughput advantage over the no-feedback curve but long enough that a system without NTC can be implemented without too much overhead for the transmitter confirmation.…”

Section: Normalized Frequencymentioning

confidence: 99%

Short-blocklength non-binary LDPC codes with feedback-dependent incremental transmissions

Vakilinia

Chen

Ranganathan

et al. 2014

2014 IEEE International Symposium on Information Theory

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Abstract-The main advantage of feedback in a point-to-point memoryless channel is the reduction of the average blocklength required to approach capacity. This paper presents a communication system with feedback that uses carefully designed nonbinary LDPC (NB-LDPC) codes and incremental transmissions to achieve 92−94% of the idealized throughput of rate-compatible sphere-packing with maximum-likelihood decoding (RCSP-ML) for average blocklengths of 150-450 bits. The system uses active feedback by carefully selecting each bit of additional incremental information to improve the reliability of the least reliable variable node. The system uses post processing in the decoder to further improve performance. The average blocklengths of 150-450 bits are small enough that feedback provides a throughput advantage but also large enough that overhead that might be associated with transmitter confirmation is more easily tolerated.

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Firing the genie: Two-phase short-blocklength convolutional coding with feedback

Cited by 4 publications

References 16 publications

Variable-Length Convolutional Coding for Short Blocklengths With Decision Feedback

Variable-Length Convolutional Coding for Short Blocklengths With Decision Feedback

Optimizing Transmission Lengths for Limited Feedback With Nonbinary LDPC Examples

Short-blocklength non-binary LDPC codes with feedback-dependent incremental transmissions

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