一种抵抗复杂干扰的工业物联网URLLC系统跨层设计方案

An industrial Internet-of-things URLLC system via cross-layer design for anti-jamming

现有蜂窝5G/B5G高可靠低时延通信(ultra-reliable and low latency communications,URLLC)标准3GPP Release 17-18采用经典正交频分复用(OFDM)多载波波形传输,因其工作在授权频带,较少考虑URLLCOFDM多载波传输抗干扰策略。未来工业物联网异构多服务质量(quality of service,QoS)业务大部分部署于非授权频带,其无线通信链路变得复杂,现有URLLC-OFDM波形无法完全为工业物联网信息传输提供高可靠性、低时延的苛刻要求。首先,基于子载波可配置的OFDMA,将鲁棒性更高的子载波跳频(subcarrier frequency hopping,Sub-FH)技术应用于OFDMA中(即Sub-FH/OFDMA),以提高信号传输可靠性。然后,设计将Sub-FH/OFDMA波形融合到以微时隙为基本单位的调度策略中。该调度策略采用Hamming编码+微时隙结合的混合自动重传请求(HARQ)机制,有效降低端到端传输的重传次数,旨在提升节点传输的实时性。并推导了信息误码(块)率与重传次数的折中理论关系。仿真结果表明,在面对外部电磁干扰和内部多用户干扰时,该方案能够保障物联网节点的稳定传输质量,并在目标误块率为10-5时实现毫秒级短数据包的传输时延。通过波形设计和MAC时隙调度的跨层级设计,为未来B5G/6G通信在复杂工业物联网场景中的实际应用提供了可行解决方案。

The classical OFDM multicarrier waveforms for transmission are adopted by the existing 5G/B5G URLLC standard(3GPP R17-18),and less attention is paid to the anti-interference strategy of URLLC-OFDM multicarrier transmission due to its operation in the licensed frequency band.In the future,unlicensed frequency bands will host most heterogeneous multi-QoS services for IIoT,resulting in complex wireless communication links.The stringent requirements of high reliability and low latency for IIoT information transmission can not be fully met by the existing URLLC-OFDM waveforms.Firstly,the more robust Sub-FH technique was applied to OFDMA based on subcarrier-configurable OFDMA(i.e.,Sub-FH/OFDMA)to improve the signal transmission reliability.Additionally,the Sub-FH/OFDMA waveforms were incorporated into a scheduling strategy with mini-slots as the basic unit.Hamming coding+mini-slot hopping HARQ were utilized by this scheduling strategy to effectively reduce the amount of retransmissions,which aim to enhance the real-time transmission among IIoT nodes.The theoretical relationship between BER/BLER and transmission delay was derived and compromises were made.Simulation results demonstrate that the scheme can ensure stable transmission quality of IIoT nodes despite external electromagnetic interference and internal multi-user interference,achieving a transmission delay of milliseconds when the target BLER is 10-5.A feasible solution for the future practical application of B5G/6G communication in complex IIoT scenarios is provided through the cross-layer design of waveform design and MAC slot scheduling in this paper.