发表机构
Amirkabir University of Technology (Tehran Polytechnic); University of British Columbia (UBC)（阿米尔卡比尔理工大学; 不列颠哥伦比亚大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对V2X广播中时变衰落、擦除和窃听问题，提出结合无速率Raptor格码、嵌套格物理层安全与区块链信任管理的协作中继框架，显著降低中断概率并有效抵御窃听。
AI 中文摘要
车联万物（V2X）侧链路和上行链路广播必须在快速时变衰落、间歇性数据包擦除以及被动窃听者暴露的条件下，可靠地传输安全关键型和应用层数据。固定速率物理层编码难以匹配这些条件，因为链路质量和成功接收的符号数量在不同车辆之间以及随时间变化。本文提出了一种统一的车辆通信框架，该框架结合了无速率Construction-D' Raptor格码、带直接序列扩频（DSSS）的嵌套格物理层安全（PLS）以及用于解码转发（DF）协作中继的区块链辅助信任管理。在物理层，Raptor码为不可靠的V2X链路提供增量冗余；多级格解码实现功率高效的联合编码和调制；嵌套成形和扩频限制窃听者对细格的恢复；分布式账本记录中继处的解码成功情况，以支持基于信誉的中继选择。我们将车辆空中接口建模为具有加性高斯噪声和随机符号擦除的块瑞利衰落信道，这代表了城市V2X侧链路的行为。所提出的码在Construction-D'内将Luby变换（LT）码与准循环低密度奇偶校验（QC-LDPC）预编码级联，并在Tanner图上消除四环。AWGN基准测试表明，与匹配长度的LDPC和LDLC格码相比，所提码具有有竞争力的符号错误率（SER）和更优的帧错误率（FER）。在带擦除的块瑞利衰落信道下，对于n=995，平均VNR为1.5 dB，擦除概率为0.15，无速率Raptor接收实现了0.3%的中断概率，平均约需2.3个数据包，在相同信道下优于LDLC和LDPC，而具有8 dB组合信噪比和扩频损耗的窃听者在62%的会话中解码失败。
英文摘要
Vehicle-to-everything (V2X) sidelink and uplink broadcast must deliver safety-critical and application-layer data reliably under fast time-varying fading, intermittent packet erasures, and exposure to passive eavesdroppers. Fixed-rate physical-layer codes are poorly matched to these conditions because link quality and the number of successfully received symbols vary across vehicles and over time. This paper proposes a unified vehicular communication framework that combines rateless Construction-D' Raptor lattices, nested-lattice physical-layer security (PLS) with direct-sequence spread spectrum (DSSS), and blockchain-assisted trust management for decode-and-forward (DF) cooperative relaying. At the physical layer, Raptor codes provide incremental redundancy over unreliable V2X links; multilevel lattice decoding enables power-efficient joint coding and modulation; nested shaping and spread spectrum limit fine-lattice recovery by eavesdroppers; and a distributed ledger records decoding success at relays to support reputation-aware relay selection. We model the vehicular air interface as a block-Rayleigh fading channel with additive Gaussian noise and random symbol erasures, representative of urban V2X sidelink behavior. The proposed code concatenates Luby-transform (LT) codes with quasi-cyclic low-density parity-check (QC-LDPC) precodes within Construction-D', with girth-4 cycle removal on the Tanner graph. AWGN benchmarks show competitive symbol error rate (SER) and improved frame error rate (FER) versus matched-length LDPC and LDLC lattices. Under block-Rayleigh fading with erasures, for n=995 at average VNR of 1.5 dB and erasure probability 0.15, rateless Raptor reception achieves 0.3% outage with about 2.3 packets on average, outperforming LDLC and LDPC under identical channels, while an eavesdropper with 8 dB combined SNR and spreading loss fails in 62% of sessions.
Comments15 pages, 9 figures, Some of the findings from this paper have been presented in IEEE CCECE 2025
