Symmetric block-wise concatenated Bose-Chaudhuri-Hocquenghem (SBC-BCH) codes are known to provide strong error-correcting performance with an iterative hard-decision decoding (IHDD). This work shows that some properties of SBC-BCH codes allow one to readily increase the error-correcting capability of constituent BCH codes by one, i.e., from t to$t + 1$, which greatly improves the error-rate performance of SBC-BCH codes. To this end, we propose a new decoding algorithm that utilizes structural features of SBC-BCH codes in conjunction with an extension of the Berlekamp-Massey (BM) algorithm, namely the one-step-ahead (OSA) BM algorithm. This combination enables us to reduce the computational complexity and combat the inherent decoding ambiguity associated with the OSA-BM algorithm. Furthermore, we develop an analytical framework to evaluate the average number of candidate codewords returned by the OSA-BM algorithm and derive an upper bound on the probability of ambiguity. Then, we propose a decoding algorithm, called OSA-aided IHDD and conduct extensive performance evaluations and comparisons for error-correcting systems employing SBC-BCH codes with the proposed decoding algorithm. The performance evaluations show that the proposed OSA-aided IHDD considerably improves the error-rate performance in both the waterfall and error-floor regions.

Congestion in the network is a persistent issue that is becoming more challenging with the advent of technologies such as metaverse and immersive AR/VR applications. Therefore, we propose Enhanced ECN (EECN), a novel network-assisted congestion feedback protocol that redesigns the legacy ECN. EECN notifies two congestion levels encoded in the existing two ECN bits, unlike ECN which delivers only Boolean information about the congestion. Additionally, we propose a congestion control algorithm that leverages this multilevel congestion feedback from the network using EECN. Our proposed EECN feedback mechanism can coexist with the legacy ECN and requires minimal changes in the end hosts. Moreover, the proposed congestion control mechanism reduces packet drops by 74% compared to ECN with TCP New Reno and 96% compared to TCP New Reno without ECN. The marked packets are reduced by 30% compared to ECN. Furthermore, the proposed approach enhances the flow completion time of short-lived network flows.

Blockchain is an effective technology that enables secure data sharing and trusted energy trading in smart grids (SGs). The consensus algorithm plays a key role in the blockchain’s security and consistency. However, due to nonconcurrency, long consensus time, low throughput, and high transaction fees, current consensus algorithms are not suitable for SGs, where there is a large-scale distributed wireless field area network (FAN) with limited resources and frequent small transactions. In this article, we propose a performance analysis model and a new consensus algorithm for the tangle in the FAN. First, we propose an analytical analysis model for the consensus time and probability of a successful parasitic chain attack on the FAN by comprehensively considering the number of data transmission hops, communication protocols, computing resources, and checked tips. Furthermore, based on the analysis, a new consensus algorithm is proposed by clustering nodes cooperating with each other to complete the Proof of Work (PoW). Finally, we show the accuracy of the analysis results by comparing them with the simulation results. Additionally, we show that the proposed consensus algorithm can reduce the required consensus time by approximately 50%.

A different approach for constructing protograph-based spatially coupled low-density parity-check (SC-LDPC) codes is proposed. Instead of lifting multiple copies of an identical SC-LDPC protograph at the lifting stage of code construction, we divide the copies into fractions$\alpha \in [{0,1}]$SC-LDPC protographs and$\beta =1-\alpha $uncoupled sequence of block LDPC protographs. The permutations in the edge bundles formed by two different protograph structures follow the multi-edge-type framework. The rate loss associated with SC-LDPC codes is reduced, and we obtain code ensembles with flexible rates, by varying$\beta $. We call these codes partial spatially coupled (PSC) LDPC codes, and through density evolution, we show that for data transmission over the binary erasure channel, the gap between channel capacity and thresholds of these codes is smaller as compared to SC-LDPC codes. The main bottleneck in the practical implementation of SC-LDPC codes is the rate loss. Conventionally, the rate loss can be reduced by taking large coupling length$L$, which however increases the decoding complexity. The proposed PSC-LDPC codes mitigate this tradeoff. Furthermore, these codes can also be decoded by the windowed decoder (WD), and through Monte Carlo simulations, we show that the WD performance of PSC-LDPC codes is better than that of SC-LDPC codes.

Sharing is undoubtedly one of the most important features of 6G networks, and blockchain can provide an extended trust-as-a-service (TAAS) distributed sharing solution for 6G networks. However, as a special distributed technology system, blockchain naturally needs to face the “impossible triangle” problem: in the case of ensuring security and decentralization, scalability will inevitably become the Achilles heel of the blockchain system. This article will design a high-throughput blockchain system for 6G networks to achieve trusted sharing and efficient scheduling of network infrastructure, assist future networks in integrating an open Internet architecture, and realize the combination of openness and distributed control. We adopt a shard blockchain design and incorporate digital twins and federated learning; formulate an optimization model for maximizing the throughput of the blockchain network by getting the optimal number of shards, also analyzing other factors affecting the throughput such as service distribution; propose a security performance analysis model for the blockchain network to describe the measures taken against the Byzantine attacks on the network. Analysis and simulation results show that the transaction throughput of the proposed method can reach more than 30 times larger than that of a nonsharding scheme. They also show that when one-third of the nodes in the system are attacked, the consensus of the system is hardly affected; even if the number of nodes being attacked at the same time reaches half of the total number of nodes, the probability of the occurrence of failed shards is still less than$10^{-4}$, and the system still has good survivability.