Mutualistic Backscatter NOMA Method for Coordinated Direct and Relay Transmission System
-
摘要: 针对现有基于非正交多址接入的直传与中继协同传输(NOMA-CDRT)难以支持海量蜂窝物联网数据融合通信的问题,该文提出一种基于反向散射的互惠NOMA-CDRT方法。首先,借助反向散射调制与功率域叠加编码,构建信息传输和辅助一体化双向通信策略,实现蜂窝用户与物联网设备的频谱共享与互惠共生。其次,在理想和非理想串行干扰消除条件下,推导所提方法遍历和速率(ESR)的闭合表达式,以精确表征其系统性能。在此基础上,进一步设计基于改进粒子群优化算法的功率分配方案,以最大化ESR。仿真结果验证了理论分析及优化方案的有效性,并显示所提方法在ESR性能上显著优于传统NOMA-CDRT与正交多址接入方法。Abstract:
Objective The exponential growth in data traffic necessitates that cellular Internet of Things (IoT) systems achieve both ultra-high spectral efficiency and wide-area coverage to meet the stringent service requirements of vertical applications such as industrial automation and smart cities. Non-Orthogonal Multiple Access-based Coordinated Direct and Relay Transmission (NOMA-CDRT) method can enhance both spectral efficiency and coverage by leveraging power-domain multiplexing and cooperative relaying, making it a promising approach to address these challenges. However, existing NOMA-CDRT frameworks are primarily designed for cellular communications and do not effectively support spectrum sharing or the deep integration of cellular and IoT transmissions. To overcome these limitations, this study proposes a Mutualistic Backscatter NOMA-CDRT (MB-NOMA-CDRT) method. This approach facilitates spectrum sharing and mutualistic coexistence between cellular users and IoT devices, while improving the system’s Ergodic Sum Rate (ESR). Methods The proposed MB-NOMA-CDRT method integrates backscatter modulation and power-domain superposition coding to develop a bidirectional communication strategy that unifies information transmission and cooperative assistance, enabling spectrum sharing and mutualistic coexistence between cellular users and IoT devices. Specifically, the base station uses downlink NOMA to serve the cellular center user directly and the cellular edge user via a relaying user. Simultaneously, IoT devices utilize cellular radio frequency signals and backscatter modulation to transmit their data to the base station, thereby achieving spectrum sharing. The backscattered IoT signals act as multipath gains, contributing to improved cellular communication quality. To rigorously characterize the system performance, the squared generalized-K distribution and Meijer-G functions are adopted to derive closed-form expressions for the ESR under both perfect and imperfect Successive Interference Cancellation (SIC). Building on this analytical foundation, a power allocation optimization scheme is developed using an enhanced Particle Swarm Optimization (PSO) algorithm to maximize system ESR. Finally, extensive Monte Carlo simulations are conducted to verify the ESR gains of the proposed method, confirm the theoretical analysis, and demonstrate the efficacy of the optimization scheme. Results and Discussions The performance advantage of the proposed MB-NOMA-CDRT method is demonstrated through comparisons of ESR with conventional NOMA-CDRT and Orthogonal Multiple Access (OMA) schemes ( Fig. 2 andFig. 3 ). The theoretical ESR results closely match the simulation data, confirming the validity of the analytical derivations. Under both perfect and imperfect SIC, the proposed method consistently achieves the highest ESR. This improvement arises from spectrum sharing between cellular users and IoT devices, where the IoT link contributes multipath gain to the cellular link, thereby enhancing overall system performance. To investigate the influence of power allocation, simulation results illustrate the three-dimensional relationship between ESR and power allocation coefficients (Fig. 4 ). A maximum ESR is observed under specific coefficient combinations, indicating that optimized power allocation can significantly improve system throughput. Furthermore, the proposed optimization scheme demonstrates rapid convergence, with ESR values stabilizing within a few iterations (Fig. 5 ), supporting its computational efficiency. Finally, ESR performance is compared among the proposed optimization scheme, exhaustive search, and fixed power allocation strategies (Fig. 6 ). The proposed scheme consistently yields higher ESR across both perfect and imperfect SIC scenarios, demonstrating its superiority in enhancing spectral efficiency while maintaining low computational complexity.Conclusions This study proposes a MB-NOMA-CDRT method that enables spectrum sharing between IoT devices and cellular users while improving cellular communication quality through the backscatter-assisted reflection link. To evaluate system performance, closed-form expressions for the ESR are derived under both perfect and imperfect SIC. Building on this analytical foundation, a power allocation optimization scheme based on PSO is developed to maximize the system ESR. Simulation results demonstrate that the proposed method consistently outperforms conventional NOMA-CDRT and OMA schemes in terms of ESR, under both perfect and imperfect SIC conditions. The optimization scheme also exhibits favorable convergence behavior and effectively improves system performance. Given its advantages in spectral efficiency and computational efficiency, the proposed MB-NOMA-CDRT method is well suited to cellular IoT scenarios. Future work will focus on exploring the mathematical conditions necessary to fully characterize and exploit the mutualistic transmission mechanism. -
1 基于改进PSO算法的功率分配方案
初始化:最大迭代次数M,粒子数Np,惯性参数$ \omega = 0.7 $,学习因子$ {\lambda _1} = 2 $, $ {\lambda _2} = 3 $,第n个粒子初始位置$ {{\mathbf{l}}_n}(0) = [{x_n}(0),{y_n}(0)] $, 初始速度$ {{\mathbf{v}}_n}(0) = [{v_{{x_n}}}(0),{v_{{y_n}}}(0)] $,且$ {x_n}(0) $和$ {y_n}(0) $分别为$ {a_{\text{c}}} $和$ {a_{\text{r}}} $规定范围内的随机数,初始个体最佳位置$ {{\mathbf{l}}_{n,{\text{p}}}}(0) = {{\mathbf{l}}_n}(0) $,全局最佳
位置$ {{\mathbf{l}}_{\text{g}}}(0) = \mathop {\arg \max }\limits_{n \in \{ 1,2, \cdots ,{N_p}\} } ({C_{\text{S}}}({{\mathbf{l}}_n}(0))) $;(1) while $ 1 \le m \le M $do (2) for $ 1 \le n \le {N_{\text{p}}} $do (3) 更新速度$ {{\mathbf{v}}_n}(m) = \omega {{\mathbf{v}}_n}(m - 1) + {\lambda _1}\zeta _{{v_n}}^1({{\mathbf{l}}_{\text{g}}}(m - 1) - {{\mathbf{l}}_n}(m - 1)) + {\lambda _2}\zeta _{{v_n}}^2({{\mathbf{l}}_{n,{\text{p}}}}(m - 1) - {{\mathbf{l}}_n}(m - 1)) $,其中$ \zeta _{{v_n}}^1 $和$ \zeta _{{v_n}}^2 $为[0,1]的
随机数;(4) 更新位置$ {{\mathbf{l}}_n}(m) = {{\mathbf{l}}_n}(m - 1) + {{\mathbf{v}}_n}(m) $; (5) 判断$ {x_n}(m) $和$ {y_n}(m) $是否在限制范围内,若超出边界值,则将其设置为该边界值; (6) 计算$ {C_{\text{S}}}({{\mathbf{l}}_{n,{\text{p}}}}(m - 1)) $,$ {C_{\text{S}}}({{\mathbf{l}}_{\text{g}}}(m - 1)) $,$ {C_{\text{S}}}({{\mathbf{l}}_n}(m)) $; (7) 更新$ {{\mathbf{l}}_{n,{\text{p}}}}(m) = \arg \max ({C_{\text{S}}}({{\mathbf{l}}_n}(m)),{C_{\text{S}}}({{\mathbf{l}}_{n,{\text{p}}}}(m - 1))) $, $ {{\mathbf{l}}_{\text{g}}}(m) = \arg \max ({C_{\text{S}}}({{\mathbf{l}}_n}(m)),{C_{\text{S}}}({{\mathbf{l}}_{\text{g}}}(m - 1))) $; (8) end for (9) 迭代次数$ m = m + 1 $; (10) end while (11) 根据$ {{\mathbf{l}}_{\text{g}}}(M) $,输出功率分配系数$ {a_{\text{c}}} $, $ {a_{\text{r}}} $和$ {a_{\text{e}}} $的最优组合。 -
[1] VAEZI M, AZARI A, KHOSRAVIRAD S R, et al. Cellular, wide-area, and non-terrestrial IoT: A survey on 5G advances and the road toward 6G[J]. IEEE Communications Surveys & Tutorials, 2022, 24(2): 1117–1174. doi: 10.1109/COMST.2022.3151028. [2] XU Yao, CHENG Julian, WANG Gang, et al. Adaptive coordinated direct and relay transmission for NOMA networks: A joint downlink-uplink scheme[J]. IEEE Transactions on Wireless Communications, 2021, 20(7): 4328–4346. doi: 10.1109/TWC.2021.3058122. [3] 李俊霞, 王欣, 黄高见, 等. 无源定位技术发展及其展望[J]. 无线电工程, 2024, 54(8): 1825–1846. doi: 10.3969/j.issn.1003-3106.2024.08.001.LI Junxia, WANG Xin, HUANG Gaojian, et al. Development and prospects of passive positioning technology[J]. Radio Engineering, 2024, 54(8): 1825–1846. doi: 10.3969/j.issn.1003-3106.2024.08.001. [4] YU Xianhua and LI Dong. Attention mechanism aided signal detection in backscatter communications with insufficient training data[J]. IEEE Transactions on Vehicular Technology, 2024, 73(5): 7395–7399. doi: 10.1109/TVT.2023.3346198. [5] JIA Shaobo, WANG Rong, LOU Yi, et al. Secrecy performance analysis of UAV-assisted ambient backscatter communications with jamming[J]. IEEE Transactions on Wireless Communications, 2024, 23(12): 18111–18125. doi: 10.1109/TWC.2024.3461800. [6] LI Dong. Two birds with one stone: Exploiting decode-and-forward relaying for opportunistic ambient backscattering[J]. IEEE Transactions on Communications, 2020, 68(3): 1405–1416. doi: 10.1109/TCOMM.2019.2957490. [7] CHEN Weiyu, DING Haiyang, WANG Shilian, et al. Backscatter cooperation in NOMA communications systems[J]. IEEE Transactions on Wireless Communications, 2021, 20(6): 3458–3474. doi: 10.1109/TWC.2021.3050600. [8] XU Yao, JIA Shaobo, ZHANG Di, et al. Spectral efficiency of D2D-enabled cellular CDRT systems leveraging backscatter NOMA[C]. 2023 IEEE Globecom Workshops (GC Wkshps), Kuala Lumpur, Malaysia, 2023: 274–279. doi: 10.1109/GCWkshps58843.2023.10464851. [9] LI Xingwang, ZHAO Mengle, ZENG Ming, et al. Hardware impaired ambient backscatter NOMA systems: Reliability and security[J]. IEEE Transactions on Communications, 2021, 69(4): 2723–2736. doi: 10.1109/TCOMM.2021.3050503. [10] LI Xingwang, WANG Qunshu, ZENG Ming, et al. Physical-layer authentication for ambient backscatter-aided NOMA symbiotic systems[J]. IEEE Transactions on Communications, 2023, 71(4): 2288–2303. doi: 10.1109/TCOMM.2023.3245659. [11] YANG Gang, XU Yinyue, and LIANG Yingchang. Resource allocation in NOMA-enhanced backscatter communication networks for wireless powered IoT[J]. IEEE Wireless Communications Letters, 2020, 9(1): 117–120. doi: 10.1109/LWC.2019.2944369. [12] 徐勇军, 姜思巧, 王公仆, 等. 基于不完美CSI的认知反向散射通信吞吐量最大化算法[J]. 电子与信息学报, 2023, 45(7): 2325–2333. doi: 10.11999/JEIT221483.XU Yongjun, JIANG Siqiao, WANG Gongpu, et al. Throughput maximization algorithm for cognitive backscatter communication with imperfect CSI[J]. Journal of Electronics & Information Technology, 2023, 45(7): 2325–2333. doi: 10.11999/JEIT221483. [13] 张倩倩, 王俊, 梁应敞. 面向6G的共生散射通信技术: 原理、方法与应用[J]. 中国科学: 信息科学, 2022, 52(8): 1393–1416. doi: 10.1360/SSI-2022-0153.ZHANG Qianqian, WANG Jun, and LIANG Yingchang. Symbiotic backscatter communications for 6G: Principles, approaches, and applications[J]. Scientia Sinica Informationis, 2022, 52(8): 1393–1416. doi: 10.1360/SSI-2022-0153. [14] LIU Yingting, ZHOU Zhiyang, YE Yinghui, et al. Outage performance analysis for mutualistic symbiotic backscatter communication systems[J]. IEEE Transactions on Vehicular Technology, 2025, 74(2): 3457–3462. doi: 10.1109/TVT.2024.3472042. [15] LONG Ruizhe, LIANG Yingchang, GUO Huayan, et al. Symbiotic radio: A new communication paradigm for passive internet of things[J]. IEEE Internet of Things Journal, 2020, 7(2): 1350–1363. doi: 10.1109/JIOT.2019.2954678. [16] XU Yao, JIA Shaobo, LI Xingwang, et al. Mutualistic relaying NOMA transmission for green cellular IoT with backscatter sensors[J]. IEEE Sensors Journal, 2024, 24(19): 31228–31244. doi: 10.1109/JSEN.2024.3441327. [17] WANG Jun, DING Xiangyu, ZHANG Qianqian, et al. Multiple access design for symbiotic radios: Facilitating massive IoT connections with cellular networks[J]. IEEE Transactions on Wireless Communications, 2024, 23(1): 201–216. doi: 10.1109/TWC.2023.3276887. [18] YE Yinghui, TIAN Yujia, CHU Xiaoli, et al. Outage performance of relay-assisted mutualistic backscatter communications under energy-causality constraint[J]. IEEE Transactions on Communications, 2025, 73(7): 4616–4629. doi: 10.1109/TCOMM.2024.3511712. [19] 李兴旺, 王新莹, 田心记, 等. 基于非理想条件可重构智能超表面辅助无线携能通信-非正交多址接入系统通感性能研究[J]. 电子与信息学报, 2024, 46(6): 2434–2442. doi: 10.11999/JEIT231395.LI Xingwang, WANG Xinying, TIAN Xinji, et al. Communication and sensing performance analysis of RIS-assisted SWIPT-NOMA system under non-ideal conditions[J]. Journal of Electronics & Information Technology, 2024, 46(6): 2434–2442. doi: 10.11999/JEIT231395. [20] 李兴旺, 田志发, 张建华, 等. IRS辅助NOMA网络下隐蔽通信性能研究[J]. 中国科学: 信息科学, 2024, 54(6): 1502–1515. doi: 10.1360/SSI-2023-0174.LI Xingwang, TIAN Zhifa, ZHANG Jianhua, et al. Performance analysis of covert communication in IRS-assisted NOMA networks[J]. Scientia Sinica Informationis, 2024, 54(6): 1502–1515. doi: 10.1360/SSI-2023-0174. [21] CHATZIDIAMANTIS N D and KARAGIANNIDIS G K. On the distribution of the sum of gamma-gamma variates and applications in RF and optical wireless communications[J]. IEEE Transactions on Communications, 2011, 59(5): 1298–1308. doi: 10.1109/TCOMM.2011.020811.090205. [22] GRADSHTEYN I S and RYZHIK I M. Table of Integrals, Series, and Products[M]. 7th ed. Amsterdam: Elsevier, 2007. (查阅网上资料, 未找到本条文献页码信息, 请补充). [23] ADAMCHIK V S and MARICHEV O I. The algorithm for calculating integrals of hypergeometric type functions and its realization in reduce system[C]. Proceedings of the International Symposium on Symbolic and Algebraic Computation, Tokyo, Japan, 1990: 212–224. doi: 10.1145/96877.96930. -