无蜂窝大规模MIMO系统中下行短包传输的叠加导频功率分配

沈璐瑶; 周星光; 许子乐; 王一航; 夏文超; 朱洪波

doi:10.11999/JEIT250655

无蜂窝大规模MIMO系统中下行短包传输的叠加导频功率分配

doi: 10.11999/JEIT250655 cstr: 32379.14.JEIT250655

1.
南京邮电大学江苏省无线通信与物联网省高校重点实验室南京 210003
2.
网络通信与安全紫金山实验室南京 211111
3.
中国移动通信集团广西有限公司南宁 530000

基金项目: 江苏省科技重大专项计划项目(BG2025038)，国家自然科学基金青年基金项目(62201285)，青年人才托举工程(2022QNRC001)

详细信息

作者简介:
沈璐瑶：女，硕士生，研究方向为短包传输、叠加导频

周星光：男，博士，研究方向为超可靠低时延通信、短包传输、大规模MIMO、信道估计理论

许子乐：女，研究方向为智能反射面，短包通信等

王一航：男，研究方向为无蜂窝网络

夏文超：男，博士，副教授，研究方向为边缘智能无线通信、通感一体化、大规模MIMO等

朱洪波：男，博士，教授，研究方向为无线通信与物联网、下一代网络、无线通信与电磁兼容

通讯作者:
夏文超　xiawenchao@njupt.edu.cn

中图分类号: TN929.5
计量
- 文章访问数: 75
- HTML全文浏览量: 29
- PDF下载量: 14
- 被引次数: 0
出版历程
- 收稿日期: 2025-07-11
- 修回日期: 2025-11-03
- 录用日期: 2025-11-03
- 网络出版日期: 2025-11-12

Power Allocation for Downlink Short Packet Transmission with Superimposed Pilots in Cell-free Massive MIMO

1.
Jiangsu Key Laboratory of Wireless Communications, Nanjing University of Posts and Telecommunications, Nanjing 210003, China
2.
Network Communication and Security of Purple Mountain Laboratories, Nanjing 211111, China
3.
China Mobile Communications Group Guangxi Co., Ltd., Nanning 530000, China

Funds: The National Science and Technology Major Project of the Ministry of Science and Technology of Jiangsu Province(BG2025038), The National Natural Science Foundation for Young Scientists of China(62201285), The Young Elite Scientists Sponsorship Program(2022QNRC001)

摘要

摘要: 无蜂窝大规模多输入多输出(CF-mMIMO)系统需要支持大量用户接入，这使得信道估计变得更加复杂。基于常规导频配置的信道估计方法占用较大开销，使得数据传输可用符号大大减少，导致传输速率下降，该问题在短包传输场景中尤为明显。对此，该文研究了CF-mMIMO系统中基于叠加导频(SP)的下行短包传输方案。首先，基于最大比传输预编码方案，在非完美信道状态信息下推导了下行可达速率的闭式表达式。为了减小SP配置下导频与数据之间的干扰，进一步提出基于几何规划和连续凸近似的迭代优化算法，以优化导频和数据间的功率分配。最后，仿真结果验证了下行可达速率闭式表达式的正确性，并表明所提SP功率优化算法能够显著提高短包传输性能。
- 无蜂窝大规模MIMO /
- 叠加导频 /
- 短包传输 /
- 功率分配
Abstract: Objective With the advancement of 5th Generation mobile communication, the volume of communication service interactions increases rapidly. To meet this growth in demand, Cell-Free Massive Multiple-Input Multiple-Output (CF-mMIMO) is regarded as a key technology. Multi-user access in CF-mMIMO systems creates complexity in channel estimation. Conventional methods based on Regular Pilots (RP) generate high overhead, which reduces the number of symbols available for data transmission. This reduction lowers the transmission rate, and the effect is stronger in short packet transmission. This study examines a downlink short packet transmission scheme based on Superimposed Pilots (SP) in CF-mMIMO systems to improve short packet transmission performance. Methods This study examines an SP-based downlink short packet transmission scenario in CF-mMIMO systems and proposes a power allocation algorithm. Considering energy consumption and resource constraints in practical settings, a User-Centric (UC) approach is used. Based on the Maximum Ratio Transmission (MRT) precoding scheme, a closed-form expression for the downlink achievable rate is derived under imperfect Channel State Information (CSI). Because pilot signals and data signals create cross-interference, an iterative optimization algorithm based on Geometric Programming (GP) and Successive Convex Approximation (SCA) is developed. The objective is to optimize the power allocation between pilot signals and data signals under the minimum data rate requirement and uplink and downlink power constraints. Using logarithmic function approximation and SCA, the non-convex optimization problem is converted into a GP problem, then an iterative algorithm is designed to obtain the solution. This study also compares the SP scheme with the RP scheme to show the superiority of the SP scheme and the proposed algorithm. Results and Discussions Simulation results confirm the accuracy of the closed-form expressions for the downlink sum rate under both SP and RP schemes (Fig. 2). To assess the effectiveness of the proposed algorithm, a comparative analysis of weighted sum rate is conducted. The comparison considers the proposed power allocation algorithm under both the SP ansd RP schemes, as well as fixed power allocation under the SP scheme. The number of antennas of APs (Fig. 3), the number of UEs (Fig. 4), block length (Fig. 5), and decoding error probability (Fig. 6) are treated as variables. The results show that the weighted sum rate achieved with the proposed power allocation algorithm under the SP scheme is higher than that achieved with the RP scheme and the fixed power allocation scheme. Conclusions This paper investigates the downlink power allocation problem under the SP scheme in CF-mMIMO systems for short packet transmission. The UC scheme is adopted to derive a closed-form expression for the lower bound of the downlink transmission rate under imperfect CSI and MRT precoding. The downlink weighted sum-rate maximization problem for the SP scheme is then formulated, and the non-convex problem is converted into a solvable GP problem through the SCA method. An iterative algorithm is employed to obtain the solution. Simulation results confirm the correctness of the closed-form expression for the transmission rate and show the superiority of the proposed power allocation algorithm.
- Cell-Free Massive Multiple-Input Multiple-Output (CF-mMIMO) /
- Superimposed Pilots (SP) /
- Short packet transmission /
- Power allocation

HTML全文

图 1 以用户为中心的CF-mMIMO 系统

下载: 全尺寸图片幻灯片

图 2 和速率模拟式与解析式的比较

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图 3 和速率与AP天线数的关系

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图 4 和速率与UE数的关系

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图 5 和速率与块长的关系

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图 6 和速率与解码错误概率的关系

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表 1 仿真参数

参数设置	数值	参数设置	数值
载波频率$f$	2.1 GHz	噪声功率谱密度	–174 dBm/Hz
信道带宽$B$	20 MHz	解码错误概率$ \epsilon $	10^–9
$ h_{\mathrm{UE}} $	1.5 m	上行链路功率限制$ P\mathrm{^{ul}} $	50 mW
$ h\mathrm{_{AP}} $	15m	下行链路功率限制$ P\mathrm{^{dl}} $	500 mW
${d_0}$	10 m	上行链路块长$ \tau\mathrm{_{ul}} $	100
${d_1}$	50 m	下行链路块长$ \tau\mathrm{_{dl}} $	100
最小速率限制$ R\mathrm{^{req}} $	1 bit/s/Hz	RP导频长度${\tau _p}$	10
AP选择系数$\lambda $	0.99	AP数M	5
每个AP的天线数N	100	UE数K	10

下载: 导出CSV

参考文献(21)

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