频谱受限下容量优化的多标签并发反射通信系统

Enhanced Capacity for Multi-Tag Concurrent Backscatter Communication Systems under Spectrum Constraints

无源反射通信技术因其微瓦级别的功耗,使得物联网设备易于部署且免维护.多标签并发反射通信技术使反射标签无需实现冲突避免等复杂协议,从而在降低设备功耗的同时提升系统的吞吐量和规模.然而,反射标签可用的频谱资源有限,导致多标签并发面临相互干扰和频谱利用效率低的问题.为此,提出了CamScatter,一个容量优化的多标签并发反射通信系统,设计了针对有限频谱资源进行最优化信道划分和高效分配的策略,避免标签之间的干扰,显著提升系统的容量.在预处理阶段,提出了带宽最大化的信道划分算法,为系统通信提供频谱上互不干扰且带宽利用率高的信道划分方案.在初始化阶段,提出了高效信道分配和最优化速率分配方案,根据系统中所有标签的信噪比,为标签分配最合适的信道和速率,以解决标签能量差异造成的信号干扰,提升系统吞吐量.在运行阶段,系统利用边带聚合和匹配滤波技术增强待解调标签信号的强度,减轻其他标签的信号干扰.系统可以利用的带宽范围为142.4~773.5 kHz,由于谐波干扰限制,理论上最大频谱利用率为81.1%,避免干扰的情况下最大系统容量为2925 kbps.仿真实验表明,算法可以实现78.6%的频谱利用率,最大系统容量可达1914 kbps.实际部署实验验证,本系统最高支持305 kbps的系统吞吐量,最多可支持30个标签的并发通信,有效解决了标签之间的相互干扰问题.

Passive backscatter communication technology,due to its microwatt-level power consumption,makes IoT devices easy to be deployed and maintenance-free.The multi-tag concurrent communication technology enables tags to avoid complex protocols such as collision avoidance,thus reducing device power consumption while increasing the system throughput and scale.However,the limited spectrum resources available to backscatter tags lead to issues of mutual interference and low spectrum utilization in multi-tag concurrency.To this end,we propose CamScatter,a capacity-enhanced multi-tag parallel backscatter communication system.We design strategies for maximizing channel division and efficient allocation with limited spectrum resources,avoiding interference among tags,and significantly enhancing the system capacity.In the preprocessing phase,a bandwidth-maximized channel division algorithm is proposed,providing multiple interference-free channel division schemes for system communication.In the initialization phase,an optimized channel and rate allocation scheme is proposed,assigning the most suitable channels and rates to tags based on the signal-to-noise ratio(SNR)of all tags in the system,thereby mitigating signal interference caused by tag energy differences and improving system throughput.Additionally,during system working,it uses sideband aggregation and matched filtering techniques to enhance signals strength of the tags to be demodulated,reducing interference from other tags.The bandwidth range that this system utilizes is from 142.4 kHz to 773.5 kHz.Due to harmonic interference limitations,the theoretical maximum spectrum utilization rate is 81.1%,and the maximum system capacity without interference is 2925 kbps.Extensive simulation experiments indicate that the algorithm proposed in this paper can achieve a spectrum utilization rate of 78.6%,with a maximum system capacity of up to 1914 kbps.Actual deployment experiments verify that our system CamScatter supports a maximum throughput of 305 kbps and can handle concurrent communication with up to 30 tags,effectively resolving the issue of mutual interference between tags.