Performance Of Convolutional Codes Research Articles

SP-DSTS-MIMO Scheme-Aided H.266 for Reliable High Data Rate Mobile Video Communication

With the ever growth of Internet users, video applications, and massive data traffic across the network, there is a higher need for reliable bandwidth-efficient multimedia communication. Versatile Video Coding (VVC/H.266) is finalized in September 2020 providing significantly greater compression efficiency compared to Highest Efficient Video Coding (HEVC) while providing versatile effective use for Ultra-High Definition (HD) videos. This article analyzes the quality performance of convolutional codes, turbo codes and self-concatenated convolutional (SCC) codes based on performance metrics for reliable future video communication. The advent of turbo codes was a significant achievement ever in the era of wireless communication approaching nearly the Shannon limit. Turbo codes are operated by the deployment of an interleaver between two Recursive Systematic Convolutional (RSC) encoders in a parallel fashion. Constituent RSC encoders may be operating on the same or different architectures and code rates. The proposed work utilizes the latest source compression standards H.266 and H.265 encoded standards and Sphere Packing modulation aided differential Space Time Spreading (SP-DSTS) for video transmission in order to provide bandwidth-efficient wireless video communication. Moreover, simulation results show that turbo codes defeat convolutional codes with an averaged Eb/N0 gain of 1.5 dB while convolutional codes outperform compared to SCC codes with an Eb/N0 gain of 3.5 dB at Bit Error Rate (BER) of . The Peak Signal to Noise Ratio (PSNR) results of convolutional codes with the latest source coding standard of H.266 is plotted against convolutional codes with H.265 and it was concluded H.266 outperform with about 6 dB PSNR gain at Eb/N0 value of 4.5 dB.

Deployment of Polar Codes for Mission-Critical Machine-Type Communication Over Wireless Networks

Mission critical Machine-type Communication, also referred to as Ultra-reliable Low Latency Communication is primarily characterized by communication that provides ultra-high reliability and very low latency to concurrently transmit short commands to a massive number of connected devices. While the reduction in PHY layer overhead and improvement in channel coding techniques are pivotal in reducing latency and improving reliability, the current wireless standards dedicated to support mcMTC rely heavily on adopting the bottom layers of general-purpose wireless standards and customizing only the upper layers. The mcMTC has a significant technical impact on the design of all layers of the communication protocol stack. In this paper, an innovative bottom-up approach has been proposed for mcMTC applications through PHY layer targeted at improving the transmission reliability by implementing ultra-reliable channel coding scheme in the PHY layer of IEEE 802.11a bearing in mind short packet transmission system. To achieve this aim, we analyzed and compared the channel coding performance of convolutional codes, LDPC codes, and polar codes in wireless network on the condition of short data packet transmission. The Viterbi decoding algorithm, logarithmic belief propagation algorithm, and cyclic redundancy check - successive cancellation list decoding algorithm were adopted to CC, LDPC codes, and polar codes, respectively. Consequently, a new PHY layer for mcMTC has been proposed. The reliability of the proposed approach has been validated by simulation in terms of Bit error rate vs. SNR. The simulation results demonstrate that the reliability of IEEE 802.11a standard has been significantly improved to be at PER less 10e-5 with the implementation of polar codes. The results also show that the general-purpose wireless networks are prominent in providing short packet mcMTC with the modification needed.

The “Nontriviality” of the Union Bound for Decoding of Convolutional Codes

Transmission of an infinite binary information sequence over a stationary memoryless channel is considered using a time-invariant non-catastrophic convolutional encoder and the Viterbi decoder. The conventional proofs of the “union upper bound” (and other upper bounds) for decoding performance of convolutional codes involve some mathematical inaccuracies. These proofs implicitly assume that all information symbols are necessarily decoded at some time and, moreover, that the decoded path on the trellis diagram “meets” the true path sooner or later. Although these facts look natural (at least, for a binary symmetric channel), they must be proved. The goal of this note is to substantiate these facts for a binary symmetric channel and a general stationary memoryless channel.

Evaluation of STBC and Convolutional Code Performance for Wireless Communication System

Evaluation of STBC and Convolutional Code Performance for Wireless Communication System

Rate-Distortion Performance of Convolutional Codes for Binary Symmetric Source

Rate-Distortion Performance of Convolutional Codes for Binary Symmetric Source

Research on the UHF RFID Channel Coding Technology based on Simulink

In this letter, we propose a new UHF RFID channel coding method, which improves the reliability of the system by using the excellent error correcting performance of the convolutional code. We introduce the coding principle of convolutional code, and compare with the cyclic codes used in the past. Finally, we analyze the error correcting performance of convolutional codes. The analysis results show that the results show that the transmission rate of the system is guaranteed, and the bit error rate can be reduced by 2.561%.

Low Latency Coding: Convolutional Codes vs. LDPC Codes

This paper compares the performance of convolutional codes to that of LDPC block codes with identical decoding latencies. The decoding algorithms considered are the Viterbi algorithm and stack sequential decoding for convolutional codes and iterative message passing for LDPC codes. It is shown that, at very low latencies, convolutional codes with Viterbi decoding offer the best performance, whereas for high LDPC codes dominate - and sequential decoding of convolutional codes offers the best performance over a range of intermediate latency values. The crossover latencies - i.e., the latency values at which the best code/decoding selection changes - are identified for a variety of code rates (1/2, 2/3, 3/4, and 5/6) and target bit/frame error rates. For sequential decoding, both blockwise and continuous resynchronization procedures are used to allow the decoder to recover the correct path. The results indicate that sequential decoding substantially extends (beyond what is possible with Viterbi decoding) the range of latency values over which convolutional codes prove advantageous compared to LDPC block codes.

Performance of Convolutional Codes in A-CDMA Systems over Time-Varying Rician Fading Channels

In this letter, the analytical and simulated performance of punctured convolutional codes in an Asynchronous Code Division Multiple Access (A-CDMA) system under imperfect phase tracking conditions are discussed. A time-varying Rician fading channel is assumed. Analytical results show the variation of the Bit Error Rate (BER) with nominal loop Signal-to-Noise Ratio (SNR) and the ratio of the loop bandwidth to the local oscillator bandwidth, $${\dfrac{B_o}{B_{Lo}}}$$ , in a phase locked loop. Simulated results are found to agree well with the analytical results.

Performance of convolutional codes in asynchronous CDMA communications under imperfect phase-tracking conditions

In this paper, the performance of short constraint length convolutional codes in imperfect phase tracking conditions is discussed. Convolutional codes are used to provide error protection to a particular user in an Asynchronous CDMA (A- CDMA) system undergoing slow Rician fading. Maximum likelihood decoding with a Viterbi algorithm recovers the information symbols. A Phase Locked Loop (PLL) depicting the variations in the phase error for abrupt phase changes in the input signal is considered. Analytical bounds, which are useful in predicting the performance of the A-CDMA system are derived and plotted for the cases of infinite and finite channel memory. The upper bounds on the unconditional Bit Error Rate (BER) with Viterbi decoding are derived and plotted for the various convolutional codes considered. The simulated BERs are found to agree well with their upper bounds.

Bit-Interleaving in Fast FH/SSMA Systems with M-FSK Modulation

The effects of bit-interleaving on the performance of convolutional codes and turbo codes in fast frequency- hop/spread-spectrum multiple-access systems with M-FSK modulation are investigated. It is observed that bit-interleaving induces two counter-acting forces on decoder performance. On the one hand, bit-interleaving disperses consecutive error bits caused by a noisy M-ary signal and makes the errors more correctable. On the other hand, the same measure makes it difficult for the decoder to make use of the bit dependency information. Both theoretical upper bounds and simulation results show that bit- interleaving degrades the performance of soft-decision decoded convolutional codes and turbo codes.

Performance of convolutional codes with finite-depth interleaving and noisy channel estimates

In this paper, we derive the Chernoff bound of the pairwise error probability (PEP) and the exact PEP of convolutional codes in a time-varying Rician fading channel. With the assumptions that the channel estimator is a finite impulse response filter and the interleaving depth is finite, we are able to investigate the estimation-diversity tradeoff resulting from the effects of the Doppler spread on the system performance via the channel-estimation accuracy and the channel diversity. In addition, we verify that, in the special case when the pilot signal-to-noise ratio is infinitely large and the channel estimator is well-designed, our analysis leads to the same result as the existing perfect channel-state information analysis. Finally, the analytical results are compared with results from Monte Carlo simulation, and the comparison shows that the analytical results match well with the simulation results

Variability study for 3G and beyond mobile communications

Convolutional codes have been widely used in DS-CDMA systems for good performance and relatively low decoding complexity. In this article we, starting from the theoretical point, study the performance of convolutional codes in an environment where E/sub b//N/sub 0/ changes sinusoidally. We study four cases of this scenario. For each case we obtain some conclusions and give their analysis. In this article a very important characteristic, named additivity, is acquired.

Convolutional coded pulse-position modulation on wireless infrared link

The performance of convolutional codes based on pulse-position modulation (PPM) for wireless infrared communication is reported. It is assumed that the receiver uses maximum-likelihood sequence detection (MLSD) to mitigate the effects of channel dispersion, which are modelled using a first-order low-pass filter. The upper bounds are derived for the minimum distance of convolutional coded PPM and compared with the Simplex bound. The performance of convolutional coded PPM is compared with the cutoff rate.

On the weight distribution of terminated convolutional codes

In this correspondence, the low-weight terms of the weight distribution of the block code obtained by terminating a convolutional code after x information blocks are expressed as a function of x. It is shown that this function is linear in x for codes with noncatastrophic encoders, but quadratic in x for codes with catastrophic encoders. These results are useful to explain the poor performance of convolutional codes with a catastrophic encoder at low-to-medium signal-to-noise ratios.

Evaluating the performance of convolutional codes over block fading channels

This correspondence considers union upper bound techniques for error control codes with limited interleaving over block fading Rician channels. A modified bounding technique is presented that relies on limiting the conditional union bound before averaging over the fading process. This technique, although analytically not very attractive, provides tight and hence useful numerical results.

Interpolation by convolutional codes, overload distortion, and the erasure channel

This paper investigates how closely randomly generated binary source sequences can be matched by convolutional code codewords. What distinguishes it from prior work is that a randomly chosen subsequence with density /spl lambda/ is to be matched as closely as possible. The so-called marked bits of the subsequence could indicate overload quantization points for a source sample generated from the tails of a probability distribution. They might also indicate bits where the initial estimate is considered reliable, as might happen in iterated decoding. The capacity of a convolutional code to interpolate the marked subsequence might be viewed as a measure of its ability to handle overload distortion. We analyze this capacity using a Markov chain whose states are sets of subsets of trellis vertices of the convolutional code. We investigate the effect of memory on the probability of perfect interpolation and calculate the residual rate on the unmarked bits of the binary source sequence. We relate our interpolation methodology to sequence-based methods of quantization and use it to analyze the performance of convolutional codes on the pure erasure channel.

Frame error rates for convolutional codes on fading channels and the concept of effective E/sub b//N/sub 0/

Estimation of Viterbi decoder performance over channels with time-varying received signal levels is the subject of this paper. This work is motivated by a desire to obtain good estimates of the frame error rate (FER) for convolutional codes with bit-level interleaving over fading channels subject to practical power control algorithms. The convolutional code performance is quantified through the FER and effective E/sub b//N/sub 0/. where the latter is defined as the E/sub b//N/sub 0/ on an additive white Gaussian noise (AWGN) channel that results in the same FER. Given a received vector of (time-varying) E/sub b//N/sub 0/ values, we compute analytic estimates for the probability of frame error and the effective E/sub b//N/sub 0/ for a Viterbi decoder and interleaver combination. In particular, we validate our analysis using the R=1/3 convolutional code and interleaver used on the IS-95 CDMA reverse channel. Comparisons with simulations show that even for E/sub b//N/sub 0/ vectors with very large variations, our proposed estimates are good to within 0.2 dB for the effective E/sub b//N/sub 0/, giving FER estimates within a factor of two-five of the simulations.

Improved upper bound on bit error rate for truncated convolutional codes

The author presents the performance of convolutional codes truncated by input information of finite length. In a convolutional code, the error rates of each bit are different. The upper bound on the error rate for each bit within a convolutional code is derived and analysed.

The performance of convolutional codes on the block erasure channel using various finite interleaving techniques

Consider the transmission of a finitely interleaved rate 1/n convolutionally encoded message over a channel with memory having two internal states /spl Xi//sub 0/ and /spl Xi//sub 1/ where when in state /spl Xi//sub 0/, the channel resembles a noiseless binary symmetric channel (BSC), whereas when in state /spl Xi//sub 1/, the channel is totally blocked and is well approximated by a binary-input single-output channel. Assume that the channel's internal state is drawn at random once every h channel uses, and then remains constant for the following h channel uses. Further assume that the message is short in comparison to h, and that due to delay constraints, the message must be decoded within Nh channel uses, where N need not be large in comparison to the code's constraint length. Such a model is appropriate for describing a convolutionally coded slow frequency hopping system with non-ideal interleaving, in which every frequency is either totally erased or else noiseless. The probability of a message error, the normalized expected number of bits in error, and the bit error rate (BER) are analytically computed for the periodic N/spl times/h bit and word interleavers, where a bit refers to a binary code symbol, and a word refers to a n-tuple of consecutive bits. An analytic expression for the BER is also given for pseudo-random word and bit interleavers and for the corresponding limiting cases of infinite interleaving, i.e., N/spl rarr//spl infin/. As an example for the use of our methods, we analyze the performance of the GSM system with various interleaving depths and methods. We introduce the notion of "matched" code and interleaver pairs, and argue that this is a desirable property. Several exhaustive searches are carried out for matched codes and interleavers.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Performance of convolutional codes with multipulse signaling in optical channels

AbstractMultipulse signaling has recently become an attractive alternative format to single pulse position modulation (PPM) utilized in optical communication systems [1]. In Ref. 2, the author analyzed the performance of short constraint length convolutional codes (CC) with the standard PPM model. In this article, CC are extended to multipulse signaling applied to both self‐noise limited, and degraded optical channels. Using this scheme, it is seen that gains in bandwidth expansion and peak‐to‐average power ratios are attainable.