Broadcast Transmission Research Articles

Empowering Learners: Online Radio Broadcasts to Enhance the Students’ Speaking Skills

The speaking skill is one of the most challenging skills to develop in the Content and Language Integrated Learning Classroom (CLIL) since it requires the student to have enough confidence and language proficiency to communicate their ideas and opinions about a topic effectively. Noticeably, students lack opportunities to talk in the classroom and use the language. As a result, the student doesn’t experience the language nor improve their oral skills. Therefore, it is imperative that schools take into consideration the use of ITC resources, such as online radio sources, because they might be useful tools wherein students can participate actively and enhance their speaking skills vastly. A quasi-experimental study was carried out in an Ecuadorian High school. The objective of this study was to measure the influence of critical thinking interviews during an online radio broadcast transmission on the students’ oral skills. 10 th graders studying Social Studies were assigned to this study. From this group, 10 students were part of the treatment group and 10 in the control group. Treatment participants were interviewed in pairs four (4) hours per week for two months on questions related to the social studies topics such as culture, gender, human rights, ethnicity, and others during the radio broadcast transmission in the English language. Data was collected by means of a speaking pre-test and post-test based on a rubric measuring four parameters: Grammar, Vocabulary, Pronunciation, and Fluency. Results were processed through SPSS software and analyzed based on the literature review. Findings demonstrated that there was a significant and positive impact on the treatment participants’ speaking skills. Keywords: online radio broadcast, communicative skills, critical thinking interview, learning autonomy, English speaking context. DOI: 10.7176/JEP/12-32-01 Publication date: November 30 th 2021

Effect of Membership Functions and Data Size on the Performance of ANFIS-Based Model for Predicting Path Losses in the VHF and UHF Bands

This paper investigates the effect of number and shape of membership function (MF), and training data size on the performance of ANFIS model for predicting path losses in the VHF and UHF bands in built-up environments. Path loss propagation measurements were conducted in four cities of Nigeria over the cellular and broadcasting frequencies. A total of 17 broadcast transmission and cellular base stations were utilized for this study. From the results obtained, it can be concluded for the broadcasting bands that the generalized bell MF shows better performance with an average RMSE of 3.00 dB across all the routes, followed by gaussian, Pi, trapezoid and triangular MFs in that other with average RMSE values of 3.09 dB, 3.11 dB, 3.16 dB and 3.23 dB respectively. For the cellular systems, Triangular MF outperformed other MFs with the lowest average RMSE. The generalized bell MF was found to be suited for WCDMA band while triangular MF is most suited for GSM band. Furthermore, it can also be concluded that the higher the number of membership functions, the lower the RMSE, whereas, a decrease in the data size leads to a reduction in the RMSE values. The findings of this study would help researchers and network planners to make a more informed decision on choosing appropriate system parameters when modeling ANFIS models for path loss prediction.

Quantifying unlinkability in multi-hop wireless networks

Consider a multi-hop wireless network in which devices act as anonymizing routers. Even if devices anonymize their link transmissions, an adversary may still be able to infer key information by observing the traffic patterns in the network. In this work, we quantify how well an adversary can infer unlinkability, that is, the probability that different pairs of devices are communicating, from anonymized link transmissions. We first propose a metric to compute unlinkability using a Kalman-filter based adversary. Using this metric, we then evaluate how different network characteristics impact unlinkability. We assume that devices do not reorder packets to mix traffic and thereby increase unlinkability. Instead, we show that traffic mixing is still possible due to the use of multi-hop routing and broadcast transmissions, with the amount of mixing dependent on the network characteristics. In simulation, we find that (i) for unicast links, as network connectivity increases unlinkability decreases, while for broadcast links, as connectivity increases unlinkability increases, (ii) link dynamics tend to increase unlinkability with unicast links but decrease unlinkability with broadcast links, (iii) well-connected topologies, particularly with broadcast links, achieve the same level of unlinkability with fewer transmissions per packet delivered, (iv) a lattice topology has consistently good unlinkability in different scenarios, and (v) heterogeneous network traffic gives higher unlinkability and better anonymization efficiency than uniform traffic, even when the average rate of traffic is the same.

On Calculating the Minimum Rate for the Cooperative Data Exchange Problem Over Fully Connected Networks

We study the cooperative data exchange problem for fully connected networks. In this problem, nodes make broadcast transmissions to recover a file consisting of K independent packets. Each node initially only possesses a subset of the packets. We propose (d, K)-Basis Searching, a deterministic polynomial-time minimization approach, to calculate the minimum rate for this problem. (d, K)-Basis Searching has strictly reduced complexity compared with the state-of-the-art algorithms, which are based on submodular function minimization. We extend our algorithm to a generalized problem: the so-called successive local omniscience problem.

Multi‐antenna diversity gain in terrestrial broadcasting receivers on vehicles: A coverage probability perspective

This paper theoretically and empirically explores the reliability gain that can be obtained by installing multiple antennas in on-vehicle broadcasting receivers. Analytical derivations reveal that maximal-ratio-combining-based diversity allows a multi-antenna receiver (MR) to achieve significantly better coverage probability than a single-antenna receiver (SR). In particular, the notable MR gains for low-power reception and high-throughput services are highlighted. We also discuss various aspects of mobile MRs, including geometric coverage, volume of the users served, and impact of receiver velocity. To examine the feasibility of MRs in the real world, extensive field experiments were conducted, particularly with on-air ATSC 3.0 broadcast transmissions. Relying on the celebrated erroneous second ratio criterion, MRs with two and four antennas were verified to achieve notable reliability gains over SRs in practice. Furthermore, our results also prove that layered-division multiplexing can cope better with receiver mobility than traditional time-division multiplexing when multiple services are intended in the same radio frequency channel.

A Selective reliable communication to reduce broadcasting for cluster based VANET

Vehicular Ad hoc Network (VANET) is one of the subset of Mobile Ad hoc Network (MANET) and it is a self-organised system with a group of vehicles, which are capable of short-range communication using On Board Unit (OBU). This unit is comprised with the vehicles that are possible to communicate with the nearby vehicles. VANETs rely on heavy broadcast transmission due to sharing data (messages) between the nearby vehicles about the traffic, collision and so on. This redundant information spoils the nature of VANET that affects the inter-vehicular communication, rebroadcasting and information on collision. This message transmission increases largely as the number of vehicles increases. This problem is typically named as broadcast storm and it is relatively reduced through the proposed Selective Reliable Communication (SRC) Protocol. Through a reliable communication, packets are retransmitted to reduce a number of transmission in the network within the acceptable level of QoS. The proposed SRC protocol automatically detect the vehicle clusters as “Zone of Interest”. Generally, the proposed protocol forwards the packets to the cluster-heads and the cluster-head forwards the packets to the cluster-members. The proposed protocol outperforms than the existing protocols in terms of Throughput, Packet Delivery Ratio (PDR) and Average delay.

PERCEPTIONS OF TEACHERS AND LEARNERS ON THE IMPACT OF COVID-19 PANDEMIC LOCKDOWN ON RURAL SECONDARY SCHOOL FEMALE LEARNERS IN MATOBO DISTRICT, ZIMBABWE

The purpose of the study was to examine the perceptions of teachers and learners on the impact of COVID-19 pandemic lockdown on rural secondary school female learners in Matobo District. The study was qualitative in nature, entrenched on interpretivist paradigm and adopted a case study design. Data was collected using open-ended questionnaire and online focus group discussions from six teachers and eighteen learners who formed three focus group discussions. The participants were purposively sampled from three schools. The study found that a few teachers were able to conduct online lessons using WhatsApp platform during COVID-19 pandemic lockdown in the selected schools though there was no consistence as teaching was not programmed and participation of female learners was low. The findings revealed that most of the parents could not afford to provide online learning resources for their children because of economic hardships. The study further established that rural female learners were at risk during COVID-19 pandemic lockdown as some of them were exposed to sexual abuse when they try to have access to smartphones and data bundles from some male adults. It was found that female learners have lost much of their learning time whilst on lockdown and many cases of pregnancy have emerged leading to dropping out of school. The study concluded that most of the rural secondary school female learners were excluded from education during lockdown due to poverty, unavailability of network or poor network coverage, lack of broadcast transmission services to enable them to access online lessons through the radio, lack of electricity, poor attendance due to lack of smartphones and data bundles, performance of all household chores including herding of cattle and lack of cooperation from some parents. The study recommended that the Ministry of Primary and Secondary Education should collaborate with stakeholders to provide necessary resources to enable all learners to access online learning despite geographical location.
 
 <p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/edu_01/0721/a.php" alt="Hit counter" /></p>

Performance Analysis of Feedback-Based Network-Coded Systems for Broadcast

In a broadcast transmission over an erasure network, feedback with network coding is both capacity-achieving and loss-immune. In this article, we carry out performance analyses of the feedback-based online network coding technique, drop when seen (DWS), and its recently proposed randomized variant (rDWS). An absorbing discrete time Markov chain (DTMC) model is constructed to find the probability of dropping a packet from the sender queue (even before decoding) in a generation-based DWS broadcast. The dropping probability is computed efficiently in homogeneous as well as in heterogeneous erasure scenario by a tensor-algebraic formulation on top of the DTMC model. Further, the notion of first time drop leads to obtain a dropping distribution. A similar inspection for rDWS is not straight-forward because of receivers’ Markov-state dependency. So, the analysis is carried out with respect to Independent Markov-state Model (IMM), and the model is shown to be accurate in most of the cases except the situations where erasure probabilities, number of receivers, field size, target time slot all are very low. Another characterization of the dropping phenomenon helps in establishing the fact, average dropping time strictly decreases with generation size for DWS , and we conjecture, the same holds for rDWS. Using the fundamental matrix concept, we calculate the mean decoding time of a generation for a receiver. Extending the idea of first time dropping to decoding, statistics of different decoding options are analyzed. Finally, some analytical and simulation plots yield, the light-weight rDWS exhibits a very close performance to DWS for a sufficiently large finite field.

A dynamic network coding MAC protocol for power line communication

Recently, power line communication (PLC) is receiving attention from academic and industry researchers worldwide. In particular, PLC systems have been largely investigated as a medium for transmitting control signals, diagnostic information, or data measured by sensors in Smart Grid. However, PLC systems face several challenges, such as multipath effects and impulsive noise, which may degrade data communication performance. To surpass such issues we propose CodePLC, a dynamic network coding MAC protocol for PLC. CodePLC relies on a single, yet dynamically chosen, relay node. This node stores and forwards linear combinations of PLC frames, which are then combined on their final destinations. We have evaluated the performance of CodePLC through simulations in a PLC system based on a time division multiple access orthogonal frequency-division multiplexing scheme. Simulation results indicate that, in broadcast transmissions, CodePLC enhances system performance. When compared to a PLC system that does not consider the use of CodePLC, based on a stop&wait MAC layer protocol, our new protocol presents an average of 115% of goodput increase. Moreover, CodePLC reduces the average network buffers occupancy by 112%. Finally, our protocol is capable of reducing the mean end-to-end latency by 400%.

Optimal Multicasting Strategies in Underwater Acoustic Networks

Recent advances in underwater networking exploit the large propagation delays in underwater channels to schedule transmissions which increase the performance of underwater acoustic sensor networks (UASNs). The underwater channel is broadcast in nature so it supports broadcast and multicast transmissions. In this paper, we discuss novel scheduling strategies, based on TDMA (Time Division Multiple Access), for UASNs where packets may be bound for multiple destinations. The main contributions are to establish an upper bound on the throughput of multicast networks, in which each packet has the same number of intended destinations, by exploiting large propagation delays, and explore network topologies that can achieve this bound. As an example, we study the throughput of unicast and multicast ring networks, including the properties of optimal, valid, perfect and fair transmission schedules. Further, several algorithms to find fair and optimal schedules for unicast and multicast ring networks are presented. Finally, we perform extensive simulations for uniform ring networks, as well as more general ring networks, in both noiseless and noisy underwater channels. Simulation results verify that the proposed algorithms can effectively determine the optimal schedules for ring networks, which achieve the maximum possible throughput and asymptotically approach the upper bound on the throughput of multicasting UASNs.

Multiple Relay Nodes Selection Scheme using Exit Time Variation for Efficient Data Dissemination in VANET

Efficient Data dissemination in VANET is still the challenge because of variable speed of vehicles, road conditions, frequent fragmentation etc. In this article a selective forwarding data dissemination scheme using exit time differences in vehicles for highway lanes scenario is proposed that focuses on the solution of broadcast storm, less coverage, transmission delay and reliable data delivery. Our approach is selecting multiple forwarding nodes to increase coverage in less delay. In this article road lanes concept is used to identify the moving node direction. Redundant regions and zones technique in proposed approach is reducing the processing of parameters at significant extents. Simulation of proposed approach is done using NS2 and SUMO. Output of implementation is compared with unidirectional flooding, KB_Selective, and LT_Selective techniques. Result analysis shown that the proposed technique is much efficient and it increases the rate of coverage up to 23%. Also it reduces the delay up to 18% in data delivery ratio. This methodology also improves the performance of system by increasing the throughput and reducing the collision rate in comparison with other methods.

CNN based watermarking technique for authentication of valid subscribers

The use of Watermarking has become very important technique for security and authentication and also many more as we are that plays a important role in providing very good security and authentication for image transmission and also in the reception, In the case of broadcasting and general transmission of confidential secret information. The deep learning techniques with multiple layers having multiple waits. The deep learning techniques are adding Intelligence (AI) to the existing models, In the recent past it has presented great success proficiencies for number of tasks, like visual investigation, speech detection, natural language processing and etc. In this process there have come up many usable models. Building up a creation level profound learning structure is a non-insignificant assignment, which requisites a lot of preparing information, amazing processing assets, and human algorithmic. Therefore, it is a very importance which can actually harm human exploration. Ill-conceived recreating, conveyance, and the induction of exclusive profound learning models can prompt copyright encroachment and it is financial mischief to demonstrate makers. Hence, it is vital for devises method to ensure the licensed innovation of profound learning model.

The Radio Hobby, Private Associations, and the Challenge of Modernity in Germany by Bruce B. Campbell

Reviewed by: The Radio Hobby, Private Associations, and the Challenge of Modernity in Germany by Bruce B. Campbell Christian Henrich-Franke (bio) The Radio Hobby, Private Associations, and the Challenge of Modernity in Germany By Bruce B. Campbell. London: Palgrave Macmillan, 2019. Pp. 370. The Radio Hobby, Private Associations, and the Challenge of Modernity in Germany By Bruce B. Campbell. London: Palgrave Macmillan, 2019. Pp. 370. In the technical modernity of the twentieth and twenty-first century, we are used to mass media, which in our private and professional lives enables us to experience events and people around the globe directly and in real-time. Technologies to communicate electronically and individually are an unquestioned part of human life. Yet at the turn of the twentieth century, such a connectivity was unimaginable. Guglielmo Marconi had just presented the possibilities of wireless communications to the public without fully understanding the physical and technical characteristics of his transmissions. In The Radio Hobby, Private Associations, and the Challenge of Modernity in Germany, Bruce B. Campbell invites us on a journey to the early history of radio communication, or "radio telegraphy," as it was called by contemporaries in the beginning. Campbell zooms in on radio (not broadcasting) as a hobby, along with private associations for it, like the Deutsche Funktechnische Verband founded in 1925. He tells the story of the often-neglected social structures that grew around mass media like radio, television, and the home computer, and which helped people use and understand new technologies. In contrast to other works on radio hobbyists—or radio amateurs as they are officially called—which are mostly interested in technical development or institutional aspects, Campbell places German hobbyists within the broader picture of societal change. Campbell emphasizes three factors in describing the challenge of technical modernity. First, he zooms in on Germany and German radio associations between the 1920s and the 1950s. The German case is particularly interesting because of the strong German tradition of associations and the very different political and social regimes that shaped the ways people were able to use, understand, and develop radio technology. Of course, he references other countries and places as well because radio hobbyists were (and still are) an international community. Second, radio was the first transnational mass medium that directly, in real-time and without a state operator, connected the private household with places far away. Third, hobbyists, who were a comparatively small community, played a key role as inventors and scientists for the development and adoption of other media technologies. The book is structured strictly chronologically. It starts with the beginning of radio at the turn of the twentieth century and the German radio before the start of regular broadcast transmissions in the early 1920s. Next, [End Page 648] Campbell describes the history of the "Radio Hobby" in Germany against the background of a changing political and social history of Germany, from the Republic of Weimar, over the national socialist times, to the Cold War and the coming into being of the Federal Republic of Germany up to the 1950s, when radio was reborn as a hobby. Campbell's book fills a gap in the history of science and technology, as it emphasizes the crucial role of hobbyists for technical progress, instead of focusing solely on the well-researched companies, standard-setting committees, engineers, or the military. In the case of radio, this applies to aspects like receiver equipment, field strength measurement, or propagation characteristics. Representatives of the hobbyists' international association, the International Amateur Radio Union (IARU), participated in conferences of global standard-setting bodies like the International Telecommunication Union throughout the twentieth century. It reminds us of shifting our attention to non-professional driving forces behind industrialized countries' transition to technical modernity. Amateur radio is an outstanding and rewarding example, as the private associations offer a broad range of journals and archives, useful in uncovering the social dynamics of (semi-)private associations. In this book, Campbell demonstrates in a very convincing way how people in Germany integrated new technologies in their daily lives and thus came to terms with a technical modernity between the 1920s and the 1950s. Radio hobbyists founded numerous and complex organizations, subdivided into national...

Context-and-Social-Aware Online Beam Selection for mmWave Vehicular Communications

Millimeter-wave (mmWave) bands are expected to be an important choice for future vehicular communication to support Gbps links for reliable data transfer in high-rate applications. The recent online learning technologies addressed the problem of fast beam tracking by exploiting user location information and mining received data in mmWave vehicular systems to adapt to the vehicle's environmental situation. However, the fairness and efficiency over mmWave beams are difficult to maintain on the move, especially for high-density traffic, since the number of available beams is quite limited by hardware and cost for current antenna arrays. Fortunately, the social structure of preferences between the neighboring smart cars and their passengers can be leveraged to improve the beam coverage efficiency by performing the broadcast transmission via a single beam. In this article, we propose a double-layer online learning algorithm, namely, context- and social-aware machine learning (CSML), that is based on the context and social preference information of vehicles and passengers, to realize fast beam access with broadcast coverage in mmWave communication systems. Based on the multiarmed bandit model, CSML embodies the selection of appropriate beams in the first layer and steers the broadcast angle along these beams in the second layer by aggregating the received data. Furthermore, CSML needs to adjust the timing of exploration and exploitation based on the social information, i.e., the probability of vehicles meeting with each other that have the same preference. Finally, we perform an extensive evaluation using realistic traffic patterns and show that CSML increases the efficiency of mmWave base stations by using social data and can achieve near-optimal system performance.

Hybrid Analog-Digital Precoder Design for Securing Cognitive Millimeter Wave Networks

Millimeter wave (mmWave) communications and cognitive radio technologies constitute key technologies of improving the spectral efficiency of communications. Hence, we conceive a hybrid secure precoder for enhancing the physical layer security of a cognitive mmWave wiretap channel, where a secondary transmitter broadcasts confidential information signals to multiple secondary users under the interference temperature constraint of the primary user (PU). The optimization problem is formulated as jointly optimizing the analog and digital precoder for maximizing the minimum secrecy rate of all the secondary users under practical constraints. In particular, our design satisfies the constraint on the maximum interference power received by multiple PUs, as well as the secondary users’ minimum quality-of-service (Qos), and the unit-modulus constraint on the analog precoder. Due to the non-convexity of the resultant objective function and owing to the coupling between the analog and digital precoder, the optimization problem formulated is nonconvex and nonlinear, hence it is very challenging to solve directly. Hence, we first transform it into a tractable form, and develop a penalty dual decomposition (PDD) based iterative algorithm to locate its Karush-Kuhn-Tucker (KKT) solution. Finally, we generalize the proposed PDD algorithm to a secure hybrid precoder design relying on practical finite-resolution phase shifters and show that the proposed PDD algorithm can be straightforwardly adapted to handle the scenario, where each PU is equipped with multiple antennas and the CSI of multiple eavesdroppers (Eves) is imperfectly known. Our simulation results validate the efficiency of the proposed iterative algorithm.

DVB-T-Based Passive Forward Scatter Radar: Inherent Limitations and Enabling Solutions

This article investigates the target detection capability of a passive forward scatter radar (PFSR) exploiting a digital video broadcasting - terrestrial (DVB-T) transmitter as illuminator of opportunity. By means of theoretical and simulated analyses, it is shown that conventional processing schemes might suffer from significant performance degradation when exploiting orthogonal frequency division multiplexing (OFDM) waveforms of opportunity compared to other broadcast transmissions (e.g., frequency modulation radio broadcast). Specifically, the direct application of conventional processing approaches to the case of a DVB-T PFSR is demonstrated to yield: 1) a nonnegligible increase of the competing background level and 2) a steeper fading of the target response due to the intrinsic characteristics of the exploited waveforms of opportunity, above all the modulation scheme and the signal spectral characteristics. Therefore, appropriate signal processing techniques are proposed to avoid these effects which jeopardize the target detection capability. The conceived processing scheme exploits the digital nature of the employed waveforms and a subband approach for improving both the interference cancellation stage and the target signature extraction. The benefits of the proposed approach are illustrated by means of theoretical and simulated analyses. The application of the resulting processing scheme against experimental data proves its effectiveness in practical scenarios.

Cooperation Between LDM-Based Terrestrial Broadcast and Broadband Unicast: On Scalable Video Streaming Applications

This article investigates the reliability gain of broadcast (BC)/broadband (BB) cooperation for mobile scalable video streaming. A specific form of BC-BB cooperation is introduced, which is referred to as cooperative casting. The proposed system primarily utilizes a BC transmission for streaming, while BB backup transmissions are requested whenever the BC signal is not decodable. For BC deliveries in this system, a cross-layer collaboration between scalable video coding (SVC) and layered-division multiplexing is used to improve spectral efficiency by coupling their hierarchical structures. In this end, in tandem with designing the uplink requesting rules based on channel status, delivery performance of the cooperative casting is analytically evaluated in a probabilistic framework. The system design and analyses presented in this article focus on the service continuity in a mobile and time-varying channel, where the physical aspects, such as delayed unicast response and inter-carrier interference, are carefully taken into account. Compared to the standalone network transmissions, the cooperative casting is numerically verified to better prevent the delivery failures in high-speed mobile channels, especially when the SVC layer-combined (full-scale video) service is intended. Furthermore, it is also shown that relaxing the criteria for the BB stream requesting can reduce delivery failures substantially, while it increases transmission redundancy.

A Novel Method for Scheduling of Wireless Ad Hoc Networks in Polynomial Time

In this article, we address the scheduling problem in wireless ad hoc networks by exploiting the computational advantage that comes when scheduling problems can be represented by claw-free conflict graphs where we consider a wireless broadcast medium. It is possible to formulate a scheduling problem of broadcast transmissions as finding the maximum weighted independent set (MWIS) in the conflict graph of the network. Finding the MWIS of a general graph is NP-hard leading to an NP-hard complexity of scheduling. In a claw-free conflict graph, MWIS may be found in polynomial time leading to a throughput-optimal scheduling. We show that the conflict graphs of certain wireless ad hoc networks are claw-free. In order to obtain claw-free conflict graphs in general networks, we suggest introducing additional conflicts (edges) with the aim of keeping the decrease in MWIS size minimal. To this end, we introduce an iterative optimization problem to decide where to introduce edges and investigate its efficient implementation. We conclude that the claw breaking method by adding extra edges can perform very close to optimal scenario and better than the polynomial time maximal independent set scheduling benchmark under the necessary assumptions.

Capacity and Delay Scaling for Broadcast Transmission in Highly Mobile Wireless Networks

Futuristic communication network formed by autonomously operated, unmanned aerial vehicles, has piqued researchers interests in highly mobile wireless networks. Exchanging safety critical information, with low latency and high throughput, in such systems is of paramount importance. We study the broadcast capacity and minimum delay scaling laws for such highly mobile wireless networks, in which each node has to disseminate packets to all other nodes in the network. In particular, we consider a cell partitioned network under an IID mobility model, in which each node chooses a new position at random, every time slot. We derive scaling laws for broadcast capacity and minimum delay as a function of the network size. We propose a simple first-come-first-serve flooding scheme, which nearly achieve both capacity and minimum delay scaling. Thus, in contrast to what has been speculated in the literature, we show that there is nearly no tradeoff between capacity and delay. Our results also show that high mobility does not improve broadcast capacity. Our analysis makes use of the theory of Markov Evolving Graphs (MEGs), and develops two new bounds on flooding time in MEGs by relaxing the previously required expander property assumption. Simulation results verify our analysis, and throw up interesting open problems.

Distributed Error Correction Coding Scheme for Low Storage Blockchain Systems

This article presents a novel way to reduce blockchain nodes’ memory requirements using error correcting codes. In particular, LDPC codes are taken as examples to explicitly demonstrate the scheme. The proposed coding scheme encodes data across multiple blocks, respectively, block headers, in the blockchain. This leads to a significant reduction in required memory at each node. We then apply the proposed coding technique to blockchains organized in two different ways. Our first scheme has the same protocol for mining, broadcasting, and verification of blocks, as Bitcoin-type blockchains. Our scheme is different in that full nodes do not have to store all blocks. Instead they will need to store only one block of a group of $t$ blocks. In the second scheme, we consider a new block verification protocol and an account-based model under the assumption that transmission between any two nodes can be established, as well as the broadcast transmission. Our block verification protocol uses the Byzantine fault tolerance algorithm and requires sending a newly mined block to only a small number of verification nodes, instead of broadcasting it to the entire network, which leads to a reduction of the network load.