Fountain Codes Research Articles

Development and prospect of fountain codes in optical wireless communication

The optical wireless communication channel is complex and changeable. Fountain codes as an emerging rateless coding can achieve adaptive transmission in different channel environments without a priori information of the channel. Compared with traditional coding, it can improve the quality of wireless transmission. In this paper, we first summarize the advantages of fountain codes applied to optical wireless communication and the domestic and foreign researches on the development status of fountain codes. Then we deeply study the design of two kinds of fountain codes coding schemes, as well as the degree distribution function which has significant influence on the performance of fountain code. Soon we put forward one kind of fountain codes, namely Luby transform (LT) codes, and introduce the optimization schemes in recent years. Meanwhile, the key difficulties that need to be solved in the fountain codes design are pointed out. Finally, the necessary technologies and explorations direction of fountain codes for wireless optical communication are proposed.

Finite Block-Length Analog Fountain Codes for Ultra-Reliable Low Latency Communications

In this paper, a theoretical framework for the design and evaluation of finite block-length analog fountain codes (AFC) towards ultra-reliable low latency communications (URLLC) is proposed. First, based on the achievable rate analysis and extrinsic information transfer (EXIT) analysis for AFC, we propose a weight adaptive (WA) AFC transmission scheme by introducing a limited feedback link, which can realize the lowest complexity AFC over a wide range SNRs. Further, by combining the conventional EXIT analysis and the dispersion perspective of mutual information, we propose a modified weight selection scheme for short block length WA-AFC (SWA-AFC) scheme. Simulation results show that our SWA-AFC scheme can achieve a superior performance than the existing AFC schemes, and approaching to the Polyansky-Poor-Verdu (PPV) bound.

An Efficient Secure and Flexible Data Sharing in Cloud Computing using Asymmetric Algorithm

Cloud Security is a technique of safeguarding applications, infrastructures and data involved in cloud computing. Cloud security uses a set of technologies, policies and controls to protect data and application from unauthorized access. RSA encryption and decryption algorithm is presented here for cloud security. The cloud can access the data only after receiving the user’s encrypted message using RSA algorithm. However, while transmitting the encrypted message more bandwidth is consumed as the message is transmitted over wireless channel. To minimize the bandwidth, the encrypted message is transmitted into a number of encoded bits and the cloud service provider can append the bits and recover the original message. The performance results for RSA algorithm and the RSA algorithm using Fountain Code are simulated. The results show that the energy, end-to-delay are minimized while using Fountain Code RSA algorithm. In addition, the packet loss ratio decrease and the packet delivery ratio increase.

Underwater Acoustic Sensor Networks With Cost Efficiency for Internet of Underwater Things

Despite the potential benefits of Internet of Underwater Things, a number of issues hinder its realization, including the need for communication reliability and cost-effectiveness. This article aims to optimize network design to implement cost-effective underwater acoustic sensor networks (UASNs) with 3D topology while supporting diverse communication quality of service (QoS) requirements. First, we present an analytical framework based on a queueing system that evaluates communication performances of UASNs, wherein each underwater sensor distributed within a 3D space under the sea surface performs fountain code (FC)-based automatic repeat request (ARQ) transmissions under the slotted-Aloha medium access control protocol. Under the proposed framework, we evaluate communication performances given in terms of successful FC-based ARQ transmission probability and the average queueing delay of an underwater sensor. When evaluating the performances, we formulate the service time of each underwater sensor as a function of network parameters, i.e., the density of data sink and amount of redundancy for FC-based ARQ transmission, before solving a function for accurate service time, such that each sensor can be represented by an M/G/1 queue. Further, our analysis can formulate an optimization problem that aims at minimizing total cost incurred to install and operate 3D UASNs, without compromising two communication QoS requirements. To solve this problem, we propose a recursive algorithm to approach an optimal solution in reasonable time. Numerical evaluations demonstrate the validity of the proposed algorithm.

Data security over wireless transmission for enterprise multimedia security with fountain codes

With the explosive growth of multimedia data, Enterprise Multimedia Security (EMS) is a serious matter to maintain enterprise information security. As the rise of social media applications triggers higher bandwidth demand and shorter end-to-end delay requirements, edge computing has emerged as a promising technique to reduce delay. Edge servers are often deployed around mobile devices via a one-hop wireless network connection. However, migrating multimedia data over wireless networks to edge servers for edge computing is vulnerable to eavesdroppers. Ensuring the security of enterprise multimedia data in the edge computing is a top priority. To cater for the data security over wireless transmisson for edge computing, window-based fountain codes, is treated as a feasible technology to compensate this gap. Based on the characteristics of the fountain codes, data security over wireless transmisson is implemented only when the target receiver accumulates enough coding packets in advance of the eavesdropper. In the general wireless transmission, the eavesdropper receives data packets or not depends on whether the wireless channel lose packets. To ensure data security, we introduce the constellation-rotation technique and interfering noise into wireless signal which can disturb the eavesdropper’s signal quality and increase the packet loss in the eavesdropper. Specifically, we study how to partition the video streaming into windows, which takes the end-to-end delay into consideration while guaranteeing lower intercept probability which indicates the probability video data is leaked to the eavesdropper.

Energy Efficiency of Multi-Hop Underwater Acoustic Networks Using Fountain Codes

Ensuring low energy consumption is a crucial issue in underwater communications, since battery replacement may be difficult and expensive in these scenarios. We analyze in this paper the energy consumption of a multi-hop underwater acoustic network (UWAN) employing fountain codes. Moreover, in order to reduce this energy consumption we optimize the modulation order assuming differential phase-shift keying ( $M$ -DPSK), as well as the number of hops. We investigate the required number of fountain-encoded packets for different modulation orders. Our results show that, by optimizing the modulation order, the number of hops and the number of fountain packets, we can obtain important energy savings, especially for long distances. In addition, with the proposed scheme the energy consumption decreases significantly compared to the case without fountain codes, reaching up to 40% of savings.

Novel fountain data estimation scheme by exploiting Bayesian model classification in wireless sensor networks

The crucial goal of fountain codes is to reduce the use of a feedback channel. Their roll-out is limited by multi-hops transmission. With the multi-hops transmission, fountain codes raise the problem of overflow engendering a waste of energy. The number of encoded packets generated is significantly reduced and the residual energy can be preserved with a clustered architecture and classification technique. In this paper, we consider a distributed estimation scheme comprising a sensor member and a fusion centre. To reduce the number of useless encoded packets and the number of transmissions, we determine the number of encoded packets to recover data. We adopt fountain codes for data encoding. Then, packets are assembled at the Cluster Head (CH). Each CH provides a final estimation using a classification. We prove the power of fountain codes and training machine learning models to exactly calculate the estimate and to preserve residual energy.

Novel fountain data estimation scheme by exploiting Bayesian model classification in wireless sensor networks

The crucial goal of fountain codes is to reduce the use of a feedback channel. Their roll-out is limited by multi-hops transmission. With the multi-hops transmission, fountain codes raise the problem of overflow engendering a waste of energy. The number of encoded packets generated is significantly reduced and the residual energy can be preserved with a clustered architecture and classification technique. In this paper, we consider a distributed estimation scheme comprising a sensor member and a fusion centre. To reduce the number of useless encoded packets and the number of transmissions, we determine the number of encoded packets to recover data. We adopt fountain codes for data encoding. Then, packets are assembled at the Cluster Head (CH). Each CH provides a final estimation using a classification. We prove the power of fountain codes and training machine learning models to exactly calculate the estimate and to preserve residual energy.

Research of LT Code Based on Key Information Feedback in Deep Space Communication

CCSDS LDPC code cannot effectively solve the problems of communication interruptions and high communication error rates in deep space communication. An application scheme of digital fountain code for deep space communication is thoroughly studied in this paper. First, an improved joint coding and decoding algorithm for LT code is proposed by adjusting the probability of the source symbol selection to achieve a nonuniform selection coding algorithm and by introducing the idea of real-time decoding on the basis of combining the BP and GE decoding algorithms to disperse the decoding complexity. Second, to ensure that the LT code can be reliably transmitted under different channel conditions, a feedback information extraction method and a retransmission coding method are designed, and an LT code transmission scheme based on key information feedback is proposed. Finally, the concatenation of the LDPC code with the LT code based on key information feedback is proposed. The LDPC code processing can be equivalently run on deep-space channels as erasure channels so that the advantage of the LT code being rateless can still be exploited in deep-space communication. Through simulation experiments, the performance of the cascade codes is analyzed from the two aspects of decoding efficiency and decoding overhead, and the performance of the cascade codes and CCSDS LDPC codes are compared from the perspective of the bit error rate. Simulation results show that the decoding efficiency of the cascade code increases, the decoding overhead decreases, and the communication bit error rate is lower in deep space communication compared with the CCSDS LDPC code. Therefore, the cascade code can improve the reliability of deep space communication.

Chase++: Fountain-Enabled Fast Flooding in Asynchronous Duty Cycle Networks

Due to limited energy supply on many Internet of Things (IoT) devices, asynchronous duty cycle radio management is widely adopted to save energy. Flooding is a critical way to disseminate messages through the whole network. Capture effect enabled concurrent broadcast is appealing to accelerate network flooding in asynchronous duty cycle networks. However, when the flooding payload's size is large, the concurrent broadcast performance is far from efficient due to the frequently unsatisfied capture effect. Intuitively, senders can send a short packet containing partial flooding payload to keep concurrent broadcast efficiency. In practice, we still face two challenges. Considering packet loss, a receiver needs an effective way to recover the entire flooding payload from several received packets as soon as possible. Moreover, considering different channel states of different senders, how a sender chooses the optimal packet length to guarantee high channel utilization is not easy. In this paper, we propose Chase++ a Fountain-code based concurrent broadcast control layer to enable fast flooding in asynchronous duty cycle networks. Chase++ uses Fountain code to alleviate the negative influence of a certain part of the flooding payload's continuous loss. Moreover, Chase++ adaptively selects packet length with the local estimation of channel utilization. Specifically, Chase++ partitions long payload into several short payload blocks, further encoded into many encoded payload blocks by Fountain-code. Then, with temporal and spatial features of the sampled RSS (received signal strength) sequence, a sender estimates the number of concurrent senders. Finally, according to the estimated number of concurrent senders, the sender determines the optimal number of encoded payload blocks in a packet and assembles the encoded payload blocks as lots of packets. Then, the concurrent broadcast layer continuously transmits these packets. Receivers can recover the original flooding payload after several independent encoded payload blocks are collected. We implement Chase++ in TinyOS with TelosB nodes. We further evaluate Chase++ on Local testbed with 50 nodes and Indriya testbed with 95 nodes. The improvement of network flooding speed can reach 23.6% and 13.4%, respectively.

A Study on the Application of Rateless Coding in Non-Cellular MIMO Systems for Machine-Type Communication

For industrial applications, communication requirements are considerably different than in most other domains. Whereas in office environments and the consumer market networks are designed towards the maximum throughput, in Industry 4.0 scenarios, traffic inficts realtime requirements, demands particular high reliability and low latency. Industrial applications of the past as well as in most current production facilities are interconnected via cable. Wireless communication in this surrounding is still a big challenge, due to the mentioned communication demands. The high demands on reliability and latency require adaptations both to the MAC layer and to the baseband signal processing of the radio system being used. Of particular importance here is the error protection coding of the radio system, the investigation of which is the subject of the given work. This needs to achieve particularly high reliability but also must not consume too much computation time, while introducing only a reasonable amount of redundancy. In order to strive for this goal, this paper examines the utilization of Fountain codes (which belong to the family of rateless codes) with very short packets (in the order of less than 100 bytes). Investigated is the impact in terms of packet error rate. It is numerically shown that the joint erasure- and error-correction coding outperforms the sole usage of either one coding scheme. Interestingly, this is true in the presence of a Rayleigh channel but also in the presence of an AWGN channel. Finally, the performance of such a method is compared to that of space time block coding.

Optimisation design of systematic fountain codes on fading channels

The asymptotic performance and optimisation of systematic fountain codes are investigated on Rayleigh fading and Nakagami fading channels. Firstly, the closed-form bit error rates (BER) of systematic LT (SLT) codes and systematic Raptor (SR) codes are derived based on Gaussian approximation method, the results of which are close to that obtained by discretised density evolution. Secondly, a novel optimisation model combining linear programming and theoretical error probability is proposed to design the degree distributions of SLT/SR codes on fading channels. The simulation results show that the optimised codes provide better BER performance than the codes originally designed for binary erasure channel and additive white Gaussian noise channel. Moreover, the proposed method is easily extended to Rician fading channel and unfading channel.

Fast Serial Iterative Decoding Algorithm for Zigzag Decodable Fountain Codes by Efficient Scheduling

Fast Serial Iterative Decoding Algorithm for Zigzag Decodable Fountain Codes by Efficient Scheduling

A digital fountain retrospective

We introduced the concept of a digital fountain as a scalable approach to reliable multicast, realized with fast and practical erasure codes, in a paper published in ACM SIGCOMM '98. This invited editorial, on the occasion of the 50th anniversary of the SIG, reflects on the trajectory of work leading up to our approach, and the numerous developments in the field in the subsequent 21 years. We discuss advances in rateless codes, efficient implementations, applications of digital fountains in distributed storage systems, and connections to invertible Bloom lookup tables.

Quantum key distribution based on total angular momentum and fountain codes

In this paper, we propose a quantum key distribution protocol based on the protocol of Simon et al (2014 New J. Phys. 16 063052) which utilized the total angular momentum (TAM) and the orbital angular momentum for key generation. In our protocol, we simplify the experimental setup to generate the key with TAM and spin angular momentum, and propose a new implementation of d-dimensional Bennett and Brassard 1984 (BB84) protocol. In our protocol, we also present a feasible implementation for privacy amplification by using the idea of fountain codes. According to the eavesdropping detection results and the channel conditions, the legal users, Alice and Bob can dynamically adjust the parameters to reach a balance between the encoding efficiency and the security. For instance, when the interception efficiency Eint of the adversary Eve is less than , Alice and Bob can set the minimum degree of fountain codes to 8, Eve’s key rate is only of Alice and Bob’s, it’s secure enough in many cases. When Eint is less than , it is also secure enough as before even Alice and Bob switch the minimum degree to only 2, therefore, many channels and computation resources are saved.

Performance Comparison between Fountain Codes-Based Secure MIMO Protocols with and without Using Non-Orthogonal Multiple Access

In this paper, we propose and evaluate the performance of fountain codes (FCs) based secure transmission protocols in multiple-input-multiple-output (MIMO) wireless systems, in presence of a passive eavesdropper. In the proposed protocols, a source selects its best antenna to transmit fountain encoded packets to a destination that employs selection combining (SC) or maximal ratio combing (MRC) to enhance reliability of the decoding. The transmission is terminated when the destination has a required number of the encoded packets to reconstruct the original data of the source. Similarly, the eavesdropper also has the ability to recover the source data if it can intercept a sufficient number of the encoded packets. To reduce the number of time slots used, the source can employ non-orthogonal multiple access (NOMA) to send two encoded packets to the destination at each time slot. For performance analysis, exact formulas of average number of time slots (TS) and intercept probability (IP) over Rayleigh fading channel are derived and then verified by Monte-Carlo simulations. The results presented that the protocol using NOMA not only reduces TS but also obtains lower IP at medium and high transmit signal-to-noise ratios (SNRs), as compared with the corresponding protocol without using NOMA.

Overlapped LT codes over the binary erasure channel: analysis and design

Fountain codes are promising forward error correction codes suitable for broadcast and multicast applications where many users with different capabilities are involved in the system. Fixed-rate codes need a priori information about each channel to decide the best code rate and the code rate is usually chosen according to the worst channel to avoid an outage. Fountain codes are agnostic to the channel conditions and rateless. The rate is realised based on the channel conditions for users separately. Overlapped fountain codes were previously invented over the binary erasure channel to provide more degrees of freedom and better trade-offs for the rateless-coded system parameters. In this study, the authors show via analysis and simulations that overlapped fountain codes need fewer decoding steps in comparison with the conventional fountain codes. For example, overlapped fountain codes reduce the number of decoding steps/iterations of belief propagation decoder by 29 % even at a source length k = 256 . They optimise the overlap selection probability of the overlapped fountain codes to maximise the code rate and/or minimise the complexity. At source length, k = 256 , the proposed analytical and simulation studies show that the highest code rate and lowest average complexity are achieved at an overlap selection probability p = 0.6 .

Caching in heterogeneous satellite networks with fountain codes

SummaryIn this paper, we investigate the performance of caching schemes based on fountain codes in a heterogeneous satellite network. We consider multiple cache‐aided hubs, which are connected to a geostationary satellite through backhaul links. With the aim of reducing the average number of transmissions over the satellite backhaul link, we propose the use of a caching scheme based on fountain codes. We derive a simple analytical expression of the average backhaul transmission rate and provide a tight upper bound on it. Furthermore, we show how the performance of the fountain code‐based caching scheme is similar to that of a caching scheme based on maximum distance separable codes.

Delay-aware fountain codes for video streaming with optimal sampling strategy

The explosive demand of on-line video from smart mobile devices poses unprecedented challenges to delivering high quality of experience (QoE) over wireless networks. Streaming high-definition video with low delay is difficult mainly due to (i) the stochastic nature of wireless channels and (ii) the fluctuating videos bit rate. To address this, we propose a novel delay-aware fountain coding (DAF) technique that integrates channel coding and video coding. In this paper, we reveal that the fluctuation of video bit rate can also be exploited to further improve fountain codes for wireless video streaming. Specifically, we develop two coding techniques: the time-based sliding window and the optimal window-wise sampling strategy. By adaptively selecting the window length and optimally adjusting the sampling pattern according to the ongoing video bit rate, the proposed schemes deliver significantly higher video quality than existing schemes, with low delay and constant data rate. To validate our design, we implement the protocols of DAF, DAF-L (a low-complexity version) and the existing delay-aware video streaming schemes by streaming H.264/AVC standard videos over an 802.11b network on CORE emulation platform. The results show that the decoding ratio of our scheme is 15% to 100% higher than the state of the art techniques.

Maximization of Underwater Sensor Networks Lifetime via Fountain Codes

The severe nature of underwater channel poses a great challenge for prolonging underwater acoustic sensor networks (UASNs) lifetime and achieving a reliable communication performance. Traditional approaches to improve the reliability such as automatic repeat request (ARQ) negatively affect the network lifetime (NL) due to energy dissipation caused by ARQ retransmission. A forward error correction (FEC) technique called fountain codes (FCs) can solve the energy efficiency problem of ARQ by transmitting both the original packet and some redundant packets to ensure a targeted reliability with few or no retransmissions. In this paper, we investigate performances of both traditional ARQ- and FC-based FEC methods in terms of NL, end-to-end delay, energy consumption, and frame error rate (FER) for UASNs. In this context, we abstract energy dissipation characteristics of conventional ARQ- and FC-based FEC method at the link-layer. We propose an integer linear programming (ILP) framework that maximizes the NL, which is operated on top of developed link-layer energy consumption models. Our results reveal that FC-based FEC methods can prolong the NL at a minimum of 16% while end-to-end delay, energy consumption, and FER can be reduced at least by 11%, 14%, and 9% as compared to classical ARQ, respectively.