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Abstract Free space optical communication (FSO) has become a popular research direction due to its high bandwidth, easy deployment, and inherent security. Its channel state is unstable because of atmospheric environment, especially in long‐distance ground transmission system. Interleaving combined with forward error correction coding (FEC) have been utilised to improve the stability of system. However, there is little detailed experimental results of deep interleaving combined with FEC under different atmospheric turbulence intensity over long‐distance FSO system. A deep interleaving with FEC method was designed and implemented on a 7 km long online experiment. The performance of different depth interleaving is analysed under weak and strong atmospheric turbulence state. The experiment results show that deep interleaving performs better under weak turbulence for the larger correlation factor of the channel and the outage probability of the system with deep interleaving can be greatly reduced.

In channel coding, reducing power consumption and improving energy efficiency are major challenges in sliding window decoding (SWD) architectures for spatially coupled low-density parity-check (SC-LDPC) codes. In contrast to the well-elaborated literature on energy-efficient decoder implementations of classical LDPC block codes (LDPC-BCs), there is little research on the aforementioned challenges for SC-LDPC codes. Thus, in this paper, we investigate a novel approach for energy-efficient implementation of very high-throughput SWD for SC-LDPC codes. First, our approach proposes an analogy to state-ofthe- art iteration control techniques for LDPC-BC decoders, by dynamically adapting the window size for the decoding of SC-LDPC codes. For this purpose, we derive new algorithms that sequentially activate and/or deactivate the processors inside the window, without loss in error correction performance. Second, we propose an architecture for very high-throughput decoder implementations. Furthermore, to meet the high throughput requirements and improve energy efficiency, we revisit the window-size adaption criteria and slightly relax the derived algorithms in terms of error correction capability. Implementation results of the new revisited full-adaptive decoder in a 12 nm technology show that, at a negligible loss in error correction performance, the proposed adaptive SWD approach improves the energy efficiency by a factor of 1.4 to 3.4 compared to the state-of-the-art in the 4 dB to 7 dB signal-to-noise-ratio (SNR) range. This improvement is further increased up to a factor of 6.5 at higher SNRs.

We consider in this paper the practical implementation of a siftingless quantum key distribution protocol. The protocol is considered siftingless since it combines sifting and error correction in a single step for basis and information reconciliation, respectively. The protocol can be efficiently implemented even assuming the existence of errors in the communication. In this case, the correlations between the legitimate parties can be modeled by a binary symmetric channel with erasures. Specific codes for this channel are included and simulated for intermediate block lengths. Simulation results show that a key reconciliation step carrying simultaneously both basis and information reconciliation can be efficiently implemented.

Low Power Wide Area Network (LPWAN) technologies have been exponentially growing because of the tremendous growth of the Internet of Things (IoT) devices across the globe. Several LPWAN technologies have been utilized by the researchers to address certain issues like increased number of collisions, retransmissions, delay, and energy consumption. However, Long Range Wide Area Network (LoRaWAN) is the most suitable and attractive technology in terms of delay optimization, low cost and efficient energy consumption. The main issue which arises in LoRaWAN is because of its high packet drop rate due to collision. The reason behind this packet drop rate is the MAC scheme known as Pure Aloha used by LoRaWAN for the transmission of the frames. Long Range (LoRa) End Devices (EDs) initiate communication with Pure Aloha that leads to a high number of retransmissions. These retransmissions further enhance the delay in LoRa networks. This paper aims to optimize the delay in LoRaWAN by using an Adaptive Scheduling Algorithm (ASA) with an unsupervised probabilistic approach called Gaussian Mixture Model (GMM). By using ASA with GMM, the retransmissions are reduced which optimizes the delay in LoRaWAN. The results show that in our approach, Packet Collision Rate (PCR) is reduced by 39% as compared to conventional LoRaWAN. In addition, the Packet Success Ratio (PSR) is also increased by 39% as compared to the conventional LoRaWAN and Dynamic Priority Scheduling Technique (PST). Further, the delay is optimized by 91% and 79%. This research could be effective for the environments where the critical data of patients need to be sent with optimised retransmissions and minimum delay towards gateways.

Recently, CRC-aided list decoding of convolutional codes has gained attention thanks to its remarkable performance in the short blocklength regime. This paper studies the convolutional and CRC codes of the Consultative Committee for Space Data System Telemetry recommendation used in space missions by all international space agencies. The distance spectrum of the concatenated CRC-convolutional code and an upper bound on its frame error rate are derived, showing the availability of a 3 dB coding gain when compared to the maximum likelihood decoding of the convolutional code alone. The analytic bounds are then compared with Monte Carlo simulations for frame error rates achieved by list Viterbi decoding of the concatenated codes, for various list sizes. A remarkable outcome is the possibility of approaching the 3 dB coding gain with nearly the same decoding complexity of the plain Viterbi decoding of the inner convolutional code, at the expense of slightly increasing the undetected frame error rates at medium-high signal-to-noise ratios. Comparisons with CCSDS turbo codes and low-density parity check codes highlight the effectiveness of the proposed solution for onboard utilization on small satellites and cubesats, due to the reduced encoder complexity and excellent error rate performance.

Reliable, fast, and deterministic communications are fundamental for future industrial wireless systems. This goal requires multiple cooperating technologies that pertain to different areas of the communication arena. The weight of the waveform and coding technique choices are critical to match industrial use cases' reliability and latency requirements. Specifically, this article contributes to the field of channel coding in wireless fieldbus links. Classical block coding schemes were designed to maximize information bit rates without stringent latency requirements. Their performance in applications that use short messages degrades significantly. Recently, sparse vector coding (SVC) has been proposed as a coding approach suitable for short-packet communications with moderate complexity and low processing latency. This article presents a comprehensive analysis of SVC and a reference communication framework for its implementation on a wireless system. A set of simulations is also designed to establish the cross correlation between the different parameters involved in the code design. As a result, the coding matrix has been identified as a critical parameter that can improve coding performance. In addition, this article includes two new procedures for determining the matrix that could lead to a gain of up to 2 dB with respect to the current state of the art.

In digital baseband processing, the forward error correction (FEC) unit belongs to the most demanding components in terms of computational complexity and power consumption. Hence, efficient implementation of FEC decoders is crucial for next-generation mobile broadband standards and an ongoing research topic. Quantization has a significant impact on the decoder area, power consumption and throughput. Thus, lower bit widths are preferred for efficient implementations but degrade the error correction capability. To address this issue, a non-uniform quantization based on the Information Bottleneck (IB) method is proposed that enables a low bit width while maintaining the essential information. Many investigations on the use of the IB method for Low-density parity-check code) LDPC decoders exist and have shown its advantages from an implementation perspective. However, for polar code decoder implementations, there exists only one publication that is not based on the state-of-the-art Fast Simplified Successive-Cancellation (Fast-SSC) decoding algorithm, and only synthesis implementation results without energy estimation are shown. In contrast, our paper presents several optimized Fast-SSC polar code decoder implementations using IB-based quantization with placement and routing results using advanced 12 nm FinFET technology. Gains of up to 16% in area and 13% in energy efficiency are achieved with IB-based quantization at a Frame Error Rate (FER) of 10−7 and a polar code of N=1024,R=0.5 compared to state-of-the-art decoders.

Within the past decade, the aerospace engineering industry has evolved beyond the constraints of using single, large, custom satellites. Due to the increased reliability and robustness of commercial, off-the-shelf printed circuit board components, missions have instead transitioned towards deploying swarms of smaller satellites. Such an approach significantly decreases the mission cost by reducing custom engineering and deployment expenses. Nanosatellites can be quickly developed with a more modular design at lower risk. The Alpha mission at the Cornell University Space Systems Studio is fabricated in this manner. However, for the purpose of development, the initial proof of concept included a two-satellite system. The manuscript will discuss system engineering approaches used to model and mature the design of the pilot satellite. The two systems that will be primarily focused on are the attitude control system of the carrier nanosatellite and the radio frequency communications on the excreted femto-satellites. Milestones achieved include ChipSat to ChipSat communication, ChipSat to ground station communication, packet creation, error correction, appending a preamble, and filtering the signal. Other achievements include controller traceability/verification and validation, software rigidity tests, hardware endurance testing, Kane damper, and inertial measurement unit tuning. These developments matured the technological readiness level (TRL) of systems in preparation for satellite deployment.

In real-time video streaming, data packets are transported over the network from a transmitter to a receiver. The quality of the received video fluctuates as the network conditions change, and it can degrade substantially when there is considerable packet loss. Forward error correction (FEC) techniques can be used to recover lost packets by incorporating redundant data. Conventional FEC schemes do not work well when scalable video coding (SVC) is adopted. In this paper, we propose a novel FEC scheme that overcomes the drawbacks of these schemes by considering the reference picture structure of SVC and weighting the reference pictures more when FEC redundancy is applied. The experimental results show that the proposed FEC scheme outperforms conventional FEC schemes.

Multicast communication over wireless networks has many potential applications, such as real-time audiovisual content distribution or digital signage systems with multiple remote terminals. However, today’s common 802.11 networks cannot fully support such applications at the link layer due to the technical challenges in achieving both high transmission rate and high reliability for multicast data transfers. Those challenges primarily emerge from the inapplicability of immediate acknowledgment mechanisms of unicast transmissions to the multicast case and the need for finding a common transmission rate for all receivers with diverse channel conditions. The research literature in this domain mainly addresses the problem at the higher layers of the protocol stack. In this article, we present a novel approach that combines wireless link rate selection with an adaptive packet-level Forward Error Correction (FEC) mechanism in order to achieve high-rate and highly reliable multicast in 802.11 wireless networks. The integration of FEC into the 802.11 MAC layer allows direct interaction between the transmission rate and the coding scheme. As a result, potential packet losses caused by higher link rates can be compensated by the adjustable redundancy provided by FEC. In combination with an aggregated receiver feedback mechanism, this yields improved transmission efficiency and reliability for wireless multicast. We investigate this approach in a simulation environment under a realistic wireless channel model in various application scenarios with up to 50 receivers. The results represent significant performance improvements, in terms of throughput, channel utilization, and packet loss, over the state-of-the-art methods for reliable wireless multicast.

In this paper, we evaluate the selective combination of algorithms for fiber nonlinearity compensation, transceiver impairments mitigation and variable-rate coding in unrepeatered optical transmission. A post-emphasis filter and a two-stage 4×4 multiple-input and multiple-output equalizer compensate the impact of bandwidth limitations and in-phase and quadrature skew. Nonlinear compensation is accomplished by a fast-converging adaptive digital back-propagation algorithm and maximum likelihood sequence estimation. Forward error correction is provided by a variable-rate spatially-coupled low-density parity-check code. The performance and complexity of the proposed digital subsystems are experimentally evaluated by the unrepeatered wavelength division multiplexing transmission of 17×200-Gb/s (DP-16QAM 32-GBd) channels over 350-km of large effective area and low-loss single-mode fibers. The experimental results for different combinations of algorithms elucidate the trade-off of complexity and performance in unrepeatered optical transmission.

ABSTRACT Numerical investigation was done for the response of two semiconductor optical amplifiers (SOA) to direct modulation using three of the most commonly employed intensity modulation formats: non‐return‐to‐zero (NRZ), duobinary (DB) and quaternary pulse amplitude modulation (PAM‐4). It was shown that an optimized SOA not only delivers an average optical power of 18 dBm, but can also be modulated at 25.4, 28.0 and 29.3 Gb/s with the aforementioned formats, respectively. No optical or electronic assistance is considered. The use of spectral‐efficient PAM‐4 thus leads to an improvement of almost 4 Gb/s with respect to NRZ. Slightly faster modulation is reached by operating the SOA deeper into saturation. These figures fall to 12.8, 15.0 and 16.3 Gb/s after 20 km conventional single‐mode fibre propagation in C‐band. Calculation of 10 Gb/s back‐to‐back sensitivities at the low‐density parity‐check forward error correction bit‐error ratio (BER) threshold of 1×10−2 resulted in −24.5, −20.5 and −20.0 dBm for NRZ, DB and PAM‐4 modulations, with a 50 km transmission penalty lower than 3 dB for PAM‐4. This enables the use of directly modulated SOAs as transmitter alternative in high‐loss access networks, such as super‐passive optical networks, provided that further technical improvements can be performed to meet its challenging loss budget.

Fiber-wireless-Fiber links require alignment between the transmitter and receiver to a high degree of precision (typically ~ 0.01° for a link of a few meters), and channel coding can be used for mitigating the link margin reduction caused by the limited precision of the beam-steering and tracking system. This paper reports results from an experimental study of the misalignment tolerance attained by channel coding. Explicitly, the received power penalties imposed by misalignment are characterized, and then forward error correction techniques are adopted for mitigating the performance degradation inflicted, which is quantified experimentally. Our results characterize trade-offs between coding rate, decoding complexity and the degree of misalignment. Overall, an improvement of the tolerance to misalignment up to ~50% was attained for coded links compared with the uncoded counterpart.

This paper presents the design of a compact protocol for fixed-latency, high-speed, reliable, serial transmission between simple field-programmable gate arrays (FPGA) devices. Implementation of the project aims to delineate word boundaries, provide randomness to the electromagnetic interference (EMI) generated by the electrical transitions, allow for clock recovery and maintain direct current (DC) balance. An orthogonal concatenated coding scheme is used for correcting transmission errors using modified Bose–Chaudhuri–Hocquenghem (BCH) code capable of correcting all single bit errors and most of the double-adjacent errors. As a result all burst errors of a length up to 31 bits, and some of the longer group errors, are corrected within 256 bits long packet. The efficiency of the proposed solution equals 46.48%, as 119 out of 256 bits are fully available to the user. The design has been implemented and tested on Xilinx Kintex UltraScale+ KCU116 Evaluation Kit with a data rate of 28.2 Gbps. Sample latency analysis has also been performed so that user could easily carry out calculations for different transmission speed. The main advancement of the work is the use of modified BCH(15, 11) code that leads to high error correction capabilities for burst errors and user friendly packet length.

Visible light communication (VLC) offers wireless communication within short-range based on wavelength converters and light-emitting diode (LED). In the VLC system, conventional forward error correction (FEC) codes are not guaranteed to provide flicker mitigation and dimming support. Consequently, modified coding schemes are introduced for reliable VLC. These methods require complicated coding structures, use of lookup tables, and the addition of large redundancy, resulting to increased computational complexity and low transmission efficiency. In this article, we propose a coding scheme that is flicker-free and enhances the transmission efficiency for VLC systems. The proposed scheme is based on polar codes (PC) and Knuth balancing code with enhanced prefix coding technique. The results show that the proposed algorithm exhibits improved transmission efficiency compared to the PC without and with run-length limited code, for dimming values 75% (or 25%) and 87.5% (or 12.5%). Also, the proposed scheme presents a significant bit error rate (BER) performance gain compared to the schemes in literature. The proposed scheme is flicker-free, provides a simple encoding structure, does not utilize lookup tables, generates minimal number of redundancies for energy efficiency. Thus, the approach is flexible, and it is more suitable for real-time VLC systems.

According to the features of short-to-medium reach optical fiber communication systems,three high performance adaptive modulation and coding schemes were investigated.In the first one,a new dimension,forward error correction (FEC),was introduced to the traditional bit and power loading (BPL) scheme,and the three-dimensional adaptive modulation and coding were achieved.The modulation format and FEC code were allocated based on look-up table (LUT).The proposed algorithm has lower complexity and higher data rate compared to the BPL scheme.The second one was also based on LUT method where one similar data rate with the BPL scheme was achieved using partitioned precoding,but peak-to-average power ratio was reduced up to two dB,and the power efficiency was improved.In the last scheme,probabilistic shaping QAM was adopted as the modulation format,and shaping gain and almost indefinitely fine modulation granularity were achieved at the expense of certain complexity.With adaptive partitioned precoding,without decreasing data rate the number of PS-QAM was limited to reduce the complexity.The experimental results demonstrate that the proposed scheme outperforms the BPL scheme in terms of data rate and receiver sensitivity.

According to the features of short-to-medium reach optical fiber communication systems,three high performance adaptive modulation and coding schemes were investigated.In the first one,a new dimension,forward error correction (FEC),was introduced to the traditional bit and power loading (BPL) scheme,and the three-dimensional adaptive modulation and coding were achieved.The modulation format and FEC code were allocated based on look-up table (LUT).The proposed algorithm has lower complexity and higher data rate compared to the BPL scheme.The second one was also based on LUT method where one similar data rate with the BPL scheme was achieved using partitioned precoding,but peak-to-average power ratio was reduced up to two dB,and the power efficiency was improved.In the last scheme,probabilistic shaping QAM was adopted as the modulation format,and shaping gain and almost indefinitely fine modulation granularity were achieved at the expense of certain complexity.With adaptive partitioned precoding,without decreasing data rate the number of PS-QAM was limited to reduce the complexity.The experimental results demonstrate that the proposed scheme outperforms the BPL scheme in terms of data rate and receiver sensitivity.

A complete impulse radio-ultra wide band (IR-UWB) system is proposed to mitigate the impairments concerning on-body to off-body Wireless Body Area Networks (WBAN). The proposed system maintains the practical communication link between on-body sensors to the fusion center or the monitoring device held by the medical representative. Also, these sensors are assigned a recently proposed pulse shaping to mitigate the noise that existed in the IR-UWB WBAN channel. Furthermore, virtual multiple-input multiple-output (VMIMO) is proposed to perform spatial multiplexing between various sensors transmitted data. Moreover, low complex low density parity check (LDPC) encoding/decoding algorithms, including a new low complex hybrid LDPC decoding algorithm, are proposed to reduce the complexity and to enhance the bit error rate of the on-body sensors. Interestingly, low energy consumption at every sensor participating in the on-body to off-body WBAN was achieved by adopting the combination between LDPC decoders and VMIMO technique. According to simulation results, the new system enhanced the BER performance and reduced the complexity of the on-body to off-body IR-UWB communication system effectively.

Mobile multimedia communication requires considerable resources such as bandwidth and efficiency to support Quality-of-Service (QoS) and user Quality-of-Experience (QoE). To increase the available bandwidth, 5G network designers have incorporated Cognitive Radio (CR), which can adjust communication parameters according to the needs of an application. The transmission errors occur in wireless networks, which, without remedial action, will result in degraded video quality. Secure transmission is also a challenge for such channels. Therefore, this paper’s innovative scheme “VQProtect” focuses on the visual quality protection of compressed videos by detecting and correcting channel errors while at the same time maintaining video end-to-end confidentiality so that the content remains unwatchable. For the purpose, a two-round secure process is implemented on selected syntax elements of the compressed H.264/AVC bitstreams. To uphold the visual quality of data affected by channel errors, a computationally efficient Forward Error Correction (FEC) method using Random Linear Block coding (with complexity of O(k(n−1)) is implemented to correct the erroneous data bits, effectively eliminating the need for retransmission. Errors affecting an average of 7–10% of the video data bits were simulated with the Gilbert–Elliot model when experimental results demonstrated that 90% of the resulting channel errors were observed to be recoverable by correctly inferring the values of erroneous bits. The proposed solution’s effectiveness over selectively encrypted and error-prone video has been validated through a range of Video Quality Assessment (VQA) metrics.

Wireless body area network (WBAN) is a promising network aiming at enhancing the communication in medical applications. It is adopted by medical organizations due to its flexibility in remotely monitoring patient health status. WBANs suffer from many limitations due to excessive channel impairments. Low density parity check (LDPC) codes are proposed to mitigate WBAN's impairments concerning the bit error rate, complexity, and dissipated energy. In this paper, a comprehensive performance analysis of various LDPC decoding algorithms is used to improve communication and reduce complexity in implant to implant WBAN channel. Moreover, a novel low complex LDPC decoding algorithm, which has a performance close to soft decision and a decoding time close to hard decision algorithms is proposed to minimize the dissipated energy. The proposed algorithm can be classified as a hybrid decision algorithm. The results demonstrate extensive analysis and comparisons between hard, soft, and hybrid decision algorithms.

To address key challenges for beyond 5G wireless technologies in a simultaneous manner, we propose an orbital angular momentum (OAM)-based, secure, energy-efficient multidimensional coded modulation. The key idea is to employ all available degrees of freedom (DOFs) to convey the information over the wireless links, including amplitude, phase, polarization state, and spatial-domain DOFs. In particular, the OAM is associated with the azimuthal phase dependence of the wavefront, and represents an underutilized DOF. Given that OAM eigenstates are orthogonal, an arbitrary number of bits per symbol can be transmitted. Here, we propose utilizing OAM DOF not only to improve spectral and energy efficiencies, but also to significantly improve the physical-layer security of future wireless networks. To implement the OAM multiplexer and demultiplexer in the RF domain, we propose using properly designed antenna arrays. We also propose employing the Slepian sequences as either basis functions in baseband or impulse responses of antenna arrays in passband to further increase the dimensionality of the wireless system and enable beyond 1-Tb/s wireless transmission. Monte Carlo simulations demonstrate high tolerance to fading effects of LDPC-coded multidimensional signaling schemes compared with the conventional LDPC-coded QAM.

One of the major weakness of Wireless Sensor Networks is the energy consumption because of limited battery resource and battery replacement or recharging difficulty. The research presented in this paper aims to reduce the energy consumption in the physical layer because most the energy consumption occurred in this layer. This reduction will be achieved via the use of ZigBee transceiver standard at the physical layer under 2.4GHz frequency band with the reduced complexity and lower power consumption than other techniques used in Wireless Sensor Network. Furthermore, such use will also enhance energy efficiency, bit error rate, and throughput of the wireless sensor network. In this paper, three different systems have been proposed according to the type of transceiver technique used in wireless sensor network. System1 uses ZigBee transceiver standard over the wireless sensor network without any additional technique whereas system2 uses ZigBee transceiver with Convolutional Coding over the WSNs model. On the other hand, system3 uses the ZigBee transceiver with both diversity techniquesVirtual Multi-Input Multi-Output and with Convolutional Coding over the wireless sensor network model. The simulation of matlab results show that system3 achieves the best energy efficiency performance compared with the other two systems at lower quality of channel. System2 achieves the best energy efficiency performance at medium quality of channel, and system1 achieves better energy efficiency at high quality of channel.

In solar-powered wireless sensor networks (SP-WSNs), the best use of harvested energy is more important than minimizing energy consumption since energy can be supplied periodically. Meanwhile, as is well known, the reliability of the communication between sensor nodes is very limited due to the resource constraints of sensor nodes. In this paper, we propose an efficient forward error correction (FEC) scheme which can give solar-powered wireless sensor networks more reliable communication. First, the proposed scheme provides energy-adaptive operation for the best use of solar energy. It calculates the amount of surplus energy which can be used for extra operations and then determines the number of additional parity bits for FEC according to this amount of surplus energy. At the same time, it also provides a link quality model that is used to calculate the appropriate number of parity bits for error recovery required for the current data communication environment. Finally, by considering these two parity sizes, it is possible to determine the number of parity bits that can maximize the data reliability without affecting the blacking out of nodes. The evaluation of the performance of the approach was performed by comparing the amount of data collected at the sink node and the number of blackout nodes with other schemes.

In this paper, we propose an optical forward-error-correction (FEC) coding scheme with convolutional code using four-wave mixing (FWM) in a highly nonlinear fiber (HNLF) to realize an adaptive coding scheme corresponding to the signal-to-noise ratio (SNR) between nodes in photonic networks. The performance of the proposed scheme was numerically investigated for 211-1 pseudorandom bit sequence (PRBS) differential phase-shift keying (DPSK) modulated return-to-zero (RZ) format signals at 10 Gb/s. The optimized condition of optical XOR operations, which are the main components of the target coding scheme, is obtained for fiber length, signal wavelengths, and signal powers. Based on the optimized condition, the power penalties of the FEC coding scheme achieved are approximately 0.5 and -0.8 dB at BER 1/4 10-9 in the cases of twoand three-input optical XOR operations, respectively, indicating that the proposed scheme obtains a net coding gain. The high-quality coded signals, which keep 5-dB degradation of the Q-factor from its maximum value of 40, are achieved with the 6.1and 6.2-dB input power tolerances for coded signals 1 and 2, respectively.

Acoustic underwater communication is a challenging task. For a reliable transmission, not only good channel estimation and equalization, but also strong error correcting codes are needed. In this paper, we present the results of the coding competition “Wanted: Best channel codes for short underwater messages” as well as our own findings on the influence of the modulation alphabet size in the example of non-binary polar codes. Furthermore, the proposals of the competition are compared to other commonly used channel codes.

Video streaming in Wireless Sensor Networks (WSNs) is a promising and challenging application for enabling high-value services. In such a context, the reduced amount ofavailable bandwidth, as well as the low-computational power available for acquiring and processing video frames, imposes the transmission of low resolution images at a low frame rate. Considering the aforementioned limitations, the amount of information carried by each video frame must be considered of utmost importance and preserved, as much as possible, against network losses that could introduce possible artifacts in the reconstructed dynamics of the scene.In this paper we first evaluate the impact of the bit error rate on the quality of the received video stream in a real scenario, then we propose a forward error correction technique based on the use of BCH codes with the aim of preserving the video quality. The proposed technique, against already proposed techniques in the WSN research field, has been specially designed to maintain a full back-compatibility with the IEEE802.15.4 standard in order to create a suitable solution aiming at accomplishing the Internet of Things (IoT) vision. Performance results evaluated in terms of Peak Signal-to-Noise Ratio (PSNR) show that the proposed solution reaches a PSNR improvement of 4.16 dB with respect to an unprotected transmission, while requiring an additional overhead equal to 22.51% in number of transmitted bits, and minimal impact on frame rate reduction and energy consumption. When higher protection levels have been imposed, bigger PSNR values have been experienced at the cost of an increased additional overhead, lower frame rates, and bigger energy consumption values.

Forward Error Correction has been implemented with Automatic Repeat reQuest to overcome packet losses and avoid network congestion in various wireless network conditions. The number of FEC packets is needed to be generated adaptively due to various network states and burst error condition. There are a number of proposed Adaptive FEC mechanisms that can generate FEC packets adaptively for wireless network. However, this current Adaptive FEC, namely Mend FEC mechanism has major drawbacks including injecting excessive number of FEC packets into the network and consequently reducing recovery performance. This paper proposed an enhancement on Mend FEC mechanism, which is called Enhanced Adaptive FEC (EnAFEC) mechanism. The enhancement is aimed to improve recovery performance of the Mend FEC mechanism by generating FEC packets dynamically based on varying wireless network conditions. The proposed enhancement was implemented in simulation environment using the NS2 network simulation. The results show that EnAFEC mechanism outperformed the other Adaptive FEC mechanism in terms of recovery efficiency. This paper also highlights that even minimal amount of FEC packets can recover high packet losses and achieve good video quality at the receiver.

As an emerging type of Internet of Things (IoT), multimedia IoT (MIoT) has been widely used in the domains of healthcare, smart buildings/homes, transportation and surveillance. In the mobile surveillance system for vehicle tracking, multiple mobile camera nodes capture and upload videos to a cloud server to track the target. Due to the random distribution and mobility of camera nodes, wireless networks are chosen for video transmission. However, the tracking precision can be decreased because of degradation of video quality caused by limited wireless transmission resources and transmission errors. In this paper, we propose a joint source and channel rate allocation scheme to optimize the performance of vehicle tracking in cloud servers. The proposed scheme considers the video content features that impact tracking precision for optimal rate allocation. To improve the reliability of data transmission and the real-time video communication, forward error correction is adopted in the application layer. Extensive experiments are conducted on videos from the Object Tracking Benchmark using the H.264/AVC standard and a kernelized correlation filter tracking scheme. The results show that the proposed scheme can allocate rates efficiently and provide high quality tracking service under the total transmission rate constraints.

In a wireless sensor network (WSN) environment with frequent errors, forward error correction (FEC) is usually employed at the link layer to achieve reliable transmission. In the FEC scheme, the error correction rate varies depending on the length of parity used for the recovery of broken data. The longer the parity length, the higher the possible error correction rate. However, this also means that the energy consumption increases. Meanwhile, in a solar-powered WSN, the energy of each node can be periodically collected, but the amount of collected energy varies drastically depending on the harvesting environment, including factors such as the weather, season and time of day. Therefore, each node must control energy consumption according to the energy harvesting rate. The scheme proposed in this study executes this control by adaptively adjusting the parity length of FEC according to the given energy budget of a node for the next period. This means that the error recovery rate can be increased as much as possible without adversely affecting the blackout time. Simulation results show that the proposed scheme improves the amount of data collected from the entire network for each environment compared with previous schemes.

In this paper, we propose a nonuniform coded-modulation format based on iterative polar quantization (IPQ) as a scheme to enable achieving channel capacity in ultrahigh-speed optical communication systems. The proposed modulation format is coded with structured low-density parity-check (LDPC) codes optimized for Gaussian channels and, in combination with polarization-multiplexing, can achieve 800 Gb/s per wavelength aggregate rate and beyond utilizing the currently available components operating at 50 GS/s. Using coded IPQ, we show that we can achieve capacity for signal-to-noise ratios (SNRs) of up to 25 dB and increase the total propagation distance over optical transmission systems by 275 km over coded star-quadrature amplitude modulation (QAM).

According to the NALU of H.264 and the characteristic of real-time video communication,a method of data interleaving for H.264 video communication was presented.Using forward erasure correction,this method could provide the unequal protection mechanism to the H.264 video stream.The more important the H.264 video stream,the stronger protection it could provide.Furthermore,a novel format of RTP payload and encapsulation was also proposed.Simulation results show that the quality of the reconstructed video can be greatly increased with similar bit rates by using the presented method.

According to the NALU of H.264 and the characteristic of real-time video communication,a method of data interleaving for H.264 video communication was presented.Using forward erasure correction,this method could provide the unequal protection mechanism to the H.264 video stream.The more important the H.264 video stream,the stronger protection it could provide.Furthermore,a novel format of RTP payload and encapsulation was also proposed.Simulation results show that the quality of the reconstructed video can be greatly increased with similar bit rates by using the presented method.

The paper deals with the component analysis of DTV (Digital Television) and DVB (Digital Video Broadcasting) baseband channel coding. Used FEC (Forward Error Correction) error-protection codes principles are shortly outlined and the simulation model applied in Matlab is presented. Results of achieved bit and symbol error rates and corresponding picture quality evaluation analysis are presented, including the evaluation of influence of the channel coding on transmitted RGB images and their noise rates related to MOS (Mean Opinion Score). Conclusion of the paper contains comparison of DVB channel codes efficiency.

This study presents research that supplements and extends the previous works on design of space-time fully systematic unpunctured (FSU) serial concatenation of quadratic interleaved codes (SCQICs). The requirements for efficient design of the forward error correction (FEC) codecs motivated potential information-theoretic studies for enjoying the development of low-complex system components within the FEC encoder/decoder for securing the transmission reliability. Inspired by this motivation, this study not only provides design guidelines to achieve better bit error rate performance in terms of the major design factors of FSU-SCQICs, that is, component code constraint length and trellis structure, and FEC rate, but also estimates the gain gaps of different quadratic permutation (QP) structures in two crucial untouched aspects: (i) signal-to-noise ratio-region comparison on the optimality and (ii) investigation on the structural parameters of QPs, that is, cyclic shift and primitive factor.

This paper describes a three-screen television system using a block recovery rate (BRR)-based unequal error protection (UEP). The proposed in-home wireless network uses scalable video coding (SVC) and UEP with forward error correction (FEC) for maximizing the quality of service (QoS) over error-prone wireless networks. For efficient FEC packet assignment, this paper proposes a simple and efficient performance metric, a BRR which is defined as a recovery rate of temporal and quality layer from FEC assignment by analyzing the hierarchical prediction structure including the current packet loss. It also explains the SVC layer switching scheme according to network conditions such as packet loss rate (PLR) and available bandwidth (ABW). In the experiments conducted, gains in video quality with the proposed UEP scheme vary from 1 to 3 dB in Y-peak signal-to-noise ratio (PSNR) with corresponding subjective video quality improvements.

This research focuses on investigating the FEC mechanism as an error recovery over a wireless network. The existing adaptive FEC mechanism faces a major drawback, which is the reduction of recovery performance by injecting too many excessive FEC packets into the network. Thus, this paper proposes the implementation of an enhanced adaptive FEC (EnAFEC) mechanism for video transmission together with its validation process. There are two propositions in the EnAFEC enhancement, which include block length adaptation and implementation, and suitable smoothing factor value determination. The EnAFEC adjusts the FEC packets based on the wireless network condition so that excessive FEC packets can be reduced. The proposed enhancement is implemented in a simulation environment using the NS-2 network simulation. The simulation results show that EnAFEC generates less FEC packets than the other types of adaptive FEC (EAFEC and Mend FEC). In addition, a validation phase is also conducted to verify that the proposed enhancement is functioning correctly, and represents a real network situation. In the validation phase, the results obtained from the simulation are compared to the outputs of the other adaptive FEC mechanisms. The validation results show that the mechanism is successfully implemented in NS2 since the number of packet loss falls under the overlapping confidence intervals.

To make people at different places participate in the same conference, speak and discuss freely, the interactive remote video conferencing system is designed and realized based on multi-Agent collaboration. FEC (forward error correction) and tree P2P technology are firstly used to build a live conference structure to transfer audio and video data; then the branch conference port can participate to speak and discuss through the application of becoming a interactive focus; the introduction of multi-Agent collaboration technology improve the system robustness. The experiments showed that, under normal network conditions, the system can support 350 branch conference node simultaneously to make live broadcasting. The audio and video quality is smooth. It can carry out large-scale remote video conference.