Design of Novel Automatic Gain Control for Multi-service Low-bit Rate Digital Radio-over-Fibre System
-
摘要: 带通采样和数字信号处理技术使得数字光载射频(DRoF)通信系统在射频信号传输中具有显著优势,而且系统通过进一步采用数据压缩技术可实现多服务信号的低比特率传输。然而,系统进行数据压缩的同时会极大降低输入动态范围。基于对数据压缩参数的理论分析,该文提出一种新型快速两级自动增益控制(FST-AGC)算法。该算法采用周期内多阈值判定机制来调整链路增益,具有高稳定、准确和快速响应等特性。通过在数字域和模拟(RF)域进行两级自动增益控制,系统的输入动态范围大大提高。该算法被成功应用到能够同时支持3家移动运营商(MONs)所有服务的多服务低速率DRoF系统中。理论计算、软件仿真和系统测试结果都验证了该算法具有显著优势和良好性能。该算法可应用在其他各种新型网络通信系统中,如物联网(IoT)、射频识别(RFID)和未来的5G通信系统。
-
关键词:
- 数字光载射频通信系统 /
- 自动增益控制 /
- 数据压缩 /
- 快速响应
Abstract: Taking the advantage of the parallel development of electronic sampling systems and signal processing, Digital Radio-over-Fiber (DRoF) is studied extensively as a way of providing multi-service transmission at low-bit rate through data compression. However, the dynamic range is greatly lowered after data compression in the system. Based on the theoretical analysis of the compression parameters, a novel Fast-Settling Two-stage Automatic Gain Control (FST-AGC) algorithm is proposed, in which gain adjustment settling is carried out by multi-threshold decision mechanism with a fast-settling times, high stability and great accuracy. By introducing a novel gain control mechanism which simultaneously adjusts the gain in digital domain and Radio Frequency (RF) domain, the dynamic range of the system increases significantly. This algorithm has been applied to a DRoF system which supports the low-bit rate transmission of all services of 3 China Mobile Network Operators (MONs) successfully. The theoretical analysis, the simulation results and the experimental data all prove the validity of the proposed algorithm. Its promising properties and excellent performance enable its potential application to emerging networks, such as Internet of Things (IoT), Radio Frequency Intification (RFID) and the incoming 5G network. -
表 1 主AGC环路中输出功率值及增益控制对应表
序号 信号功率估计值范围 增益控制字 7 > (103)×upa ATT_31~ATT_35 6 (102.5) ×upa~(103) ×upa ATT_26~ATT_30 5 (102) ×upa~(102.5) ×upa ATT_21~ATT_25 4 (101.5) ×upa~(102) ×upa ATT_16~ATT_20 3 (101) ×upa~(101.5) ×upa a ATT_11~ATT_15 2 (100.5) ×upa~(101) ×upa ATT_6~ATT_10 1 upa~(100.5) ×upa ATT_1~ATT_5 0 lowa~upa Gain_0 –1 (10–0.5)×lowa~lowa Gain_1~Gain_5 –2 (10–1) ×lowa~(10–0.5) ×lowa Gain_6~Gain_10 –3 (10–1.5) ×lowa~(10–1) ×lowa Gain_11~Gain_15 –4 (10–2) ×lowa~(10–1.5) ×lowa Gain_16~Gain_20 –5 (10–2.5) ×lowa~(10–2) ×lowa Gain_21~Gain_25 –6 (10–3) ×lowa~(10–2.5) ×lowa Gain_26~Gain_30 –7 < (10–3) ×lowa Gain_31~Gain_35 表 2 从AGC环路中输出功率值及增益控制字对应表
序号 信号功率估计值范围 增益控制字 1 大于upb RF_ATT_1 0 lowb~upb RF_Gain_0 –1 (10–1.05)×lowb~lowb RF_Gain_1 –2 小于(10–1.05)×lowb RF_Gain_2 表 3 射频前端主要器件参数
器件 型号 增益 (dB) P1dB(dBm) IP3(dBm) NF(dB) LNA TQP3M9028 14.5 20.7 40.0 1.80 ATT PE4302 –31.5~0 34.0 52.0 1.50 PGA MGA-684P8 17.6 22.0 32.4 0.56 表 4 FST-AGC参数取值
参数 含义 取值 fs 系统时钟 153.6 MHz K 加权系数 13107 TD 控制周期 50 α 判定因子 36 Vmax 饱和门限 5000 ref 参考值 160 μ 自定义系数 1 σ LSB值 8 B ADC采样位数 16 υ MSB值 0 lowa 主AGC下门限 14 upa 主AGC上门限 1000 lowb 从AGC下门限 4 upb 从AGC上门限 1000 -
NOWEIR M, ZHOU Qiang, KWAN A, et al. Digitally linearized radio-over fiber transmitter architecture for cloud radio access network’s downlink[J]. IEEE Transactions on Microwave Theory and Techniques, 2018, 66(7): 3564–3574. doi: 10.1109/TMTT.2018.2819665 AISSAOUI K, MHATLI S, and ATTIA R. High data rate multiband GFDM over long-haul standard single mode fiber communication[C]. 2019 15th International Wireless Communications & Mobile Computing Conference (IWCMC), Tangier, Morocco, 2019: 1764–1766. doi: 10.1109/IWCMC.2019.8766716. NOWEIR M, HELAOUI M, TITTEL W, et al. Carrier aggregated radio-over-fiber downlink for achieving 2Gbps for 5G applications[J]. IEEE Access, 2019, 7: 3136–3142. doi: 10.1109/ACCESS.2018.2888820 LI Tongyun, PENTY R V, and WHITE I H. Novel digital radio over fibre for 4G-LTE[C]. 2015 IEEE International Conference on Communication Workshop (ICCW), London, UK, 2015: 312–317. doi: 10.1109/ICCW.2015.7247197. LIU Jun, LUO Zhongqiang, and XIONG Xingzhong. Low-resolution ADCs for wireless communication: A comprehensive survey[J]. IEEE Access, 2019, 7: 91291–91324. doi: 10.1109/ACCESS.2019.2927891 SHEN Yuyao, WANG Yongqing, SHENG Dewei, et al. Digital AGC based on coherent adjustment cycle for DSSS receiver[J]. China Communications, 2015, 12(2): 95–106. doi: 10.1109/CC.2015.7084405 徐化, 姚远, 石寅, 等. 一种新型的5 GHz自适应偏置及可变增益低噪声放大器[J]. 电子与信息学报, 2006, 28(8): 1521–1525.XU Hua, YAO Yuan, SHI Yin, et al. A new 5 GHz adaptively-biased and variable gain low noise amplifier[J]. Journal of Electronics &Information Technology, 2006, 28(8): 1521–1525. WU Hao and LI Jun. Analysis and mitigation of ICI due to gain adjustment in OFDM systems[J]. IEEE Access, 2019, 7: 21807–21815. doi: 10.1109/ACCESS.2019.2898457 NALLATHAMBI G and PRINCIPE J. Time based gain control for the analog to pulse converter[C]. 2017 IEEE Global Conference on Signal and Information Processing (GlobalSIP), Montreal, Canada, 2017: 216–219. doi: 10.1109/GlobalSIP.2017.8308635. HSIEH Y K, WU Yaru, KU P C, et al. An analog on-line gain calibration loop for RF amplifiers[J]. IEEE Transactions on Circuits and Systems I: Regular Papers, 2015, 62(8): 2003–2012. doi: 10.1109/TCSI.2015.2440736 PRASOLOV A. Modeling of digital AGC with multi-signal impact and adaptation of the reference level[C]. 2018 Moscow Workshop on Electronic and Networking Technologies (MWENT), Moscow, Russia, 2018: 1–4. doi: 10.1109/MWENT.2018.8337173. ZHANG Hongsheng, WANG Guoyu, and LU Mingying. Analysis and implementation of digital automatic gain control for DAB baseband decoder[J]. IEEE Transactions on Consumer Electronics, 2011, 57(2): 327–334. doi: 10.1109/TCE.2011.5955163 GUO Yongxin, PHAM V H, YEE M L, et al. Improved radio-over-fiber transponder with multistage automatic gain control[J]. IEEE Transactions on Microwave Theory and Techniques, 2009, 57(11): 2816–2823. doi: 10.1109/TMTT.2009.2032478 陈家旭, 管恩义, 李文, 等. 数字通信系统中新型自动增益控制方法设计[J]. 导航与控制, 2016, 15(6): 57–61. doi: 10.3969/j.issn.1674-5558.2016.06.010CHEN Jiaxu, GUAN Enyi, LI Wen, et al. Design of a novel automatic gain control method for digital communication system[J]. Navigation and Control, 2016, 15(6): 57–61. doi: 10.3969/j.issn.1674-5558.2016.06.010 TISSERAND E and BERVILLE Y. Design and implementation of a new digital automatic gain control[J]. Electronics Letters, 2016, 52(22): 1847–1849. doi: 10.1049/el.2016.1398 ZHANG Naikang, WEN Zhiping, HOU Xunping, et al. Digital automatic gain control design with large dynamic range in wireless communication receivers[C]. 2017 IEEE 17th International Conference on Communication Technology (ICCT), Chengdu, China, 2017: 1402–1406. doi: 10.1109/ICCT.2017.8359863. 刘冰凡, 陈伯孝. 基于OFDM-LFM信号的MIMO雷达通信一体化信号共享设计研究[J]. 电子与信息学报, 2019, 41(4): 801–808. doi: 10.11999/JEIT180547LIU Bingfan and CHEN Baixiao. Integration of MIMO radar and communication with OFDM-LFM signals[J]. Journal of Electronics &Information Technology, 2019, 41(4): 801–808. doi: 10.11999/JEIT180547 吕晓德, 张汉良, 杨璟茂, 等. 基于LTE信号的外辐射源雷达副峰特性及抑制方法研究[J]. 电子与信息学报, 2018, 40(10): 2498–2505. doi: 10.11999/JEIT180904LÜ Xiaode, ZHANG Hanliang, YANG Jingmao, et al. Research on characteristics and suppression methods of side peaks of passive radar based on LTE signal[J]. Journal of Electronics &Information Technology, 2018, 40(10): 2498–2505. doi: 10.11999/JEIT180904 程佩青. 数字信号处理教程[M]. 2版. 北京: 清华大学出版社, 2001.CHENG Peiqing. Discrese Signal Processing[M]. 2nd ed. Beijing: Tsinghua University Press, 2001.