WSN低功耗射频接收关键技术研究与芯片设计

发布时间：2018-04-28 23:27

  本文选题：无线传感网 + 低功耗　； 参考：《东南大学》2017年博士论文

【摘要】：近年来,随着无线通信系统迅速发展,各种无线通信技术己广泛应用于人们的日常生活当中。无线传感网(WSN,Wireless Sensor Network)是当前信息领域的一个研究热点,它以数据为中心,其网络结构具有自组织性并可以动态调整,具有非常高的可靠性,应用前景广阔。低功耗是无线通信系统发展的重要趋势,而低功耗射频收发技术则是实现低功耗无线通信系统的关键所在。正是在这样的应用背景下,低功耗射频收发技术被人们提出并且吸引了众多研究者的目光。研究低功耗射频收发技术对于推动无线通信系统尤其是无线传感网的发展具有重要理论意义和应用价值。本文在国家自然科学基金项目《低功耗射频收发技术研究》的支持下,主要致力于低功耗射频接收关键技术的相关研究。本文首先从系统的层面对无线传感网IEEE 802.15.4协议进行了分析,给出了低功耗射频收发机系统结构设计、整体指标计算、模块划分和链路预算的具体步骤和方法,为电路模块的研究与设计做好了铺垫。本文对低噪声放大器(LNA,Low Noise Amplifier)、下变频混频器(Down-conversion Mixer)、复数带通滤波器(CBPF,Complex Band Pass Filter)、限幅放大器(Limiter)和压控振荡器(VCO,Voltage Control Oscillator)等关键电路模块进行了研究与设计,取得的主要研究成果如下:详细分析了宽带LNA的电路结构和设计方法,提出了一种采用双电容交叉耦合技术的共栅(CG,Common Gate)LNA。论文分析了在含有交叉耦合结构的差分LNA中使用半边等效电路计算噪声系数会带来误差的原因,并采用直接法对双电容交叉耦合CG-LNA的噪声系数进行了求解。理论推导表明该结构的噪声系数明显优于传统的电容交叉耦合CG-LNA,且功耗只有传统结构的一半。最后设计并实现了一个宽带LNA,芯片测试结果表明:在1.8V电源电压下,该LNA的工作电流为1.0mA,3dB带宽为0.5～0.95GHz,电压增益为20.7dB,最小噪声系数为2.8dB。对窄带LNA进行了详细的调研,在分析了源极电感负反馈共源LNA等窄带LNA电路结构在应用中存在不足的基础上,本文提出了一种工作在1.0V低电压下采用多重跨导提升技术的2.4GHz窄带LNA电路结构,并给出了 LNA输入阻抗和电压增益的具体表达式。论文着重推导了 LNA的噪声系数公式,分析了 LNA的噪声优化过程,在此基础上设计了一个窄带LNA。在1.0V电源电压下,该LNA的工作电流为0.9mA,其3dB带宽为2.32～2.58GHz,电压增益为22.2dB,最小噪声系数为4.35dB。将双电容交叉耦合CG-LNA和采用电流注入技术的Mixer级联,设计并实现了一种低功耗0.5～1GHz宽带射频接收前端芯片,可以覆盖无线传感网IEEE 802.15.4协议中的sub-GHz频段;将采用多重跨导提升技术的CG-LNA和基于电流复用技术的Mixer级联,设计并实现了一种低电压低功耗2.4GHz窄带射频接收前端芯片。本文同时提出了一种基于LNA和Mixer电流复用的低电压低功耗0.7～2.4GHz宽带射频接收前端电路结构,其带宽可以同时覆盖无线传感网IEEE 802.15.4协议中的sub-GHz和2.4GHz频段。针对该射频前端电路,本文提出了一种图解法,可以对其各项性能参数进行分析、优化和折中。该设计方法简单直观,并且取得了良好的效果。芯片测试结果表明:在1.0V电源电压下,整个射频接收前端电路的工作电流为0.83mA,sub-GHz频段的电压增益为25.0dB,噪声系数小于6.9dB,2.4GHz频段的电压增益为18.2dB,噪声系数小于10.2dB。与已有文献报道中的设计相比较,该设计具有更优的综合性能。对射频接收链路中的复数带通滤波器进行了深入的研究,分析了已有的电路结构和设计优化方法。为了进一步简化电路结构,降低功耗,本文提出了一种基于极点构造的复数带通滤波器设计方法。采用该方法设计完成的四阶复数带通滤波器总共含有8个差分跨导单元,和基于二阶滤波单元的有源Gm-C结构相比,跨导单元数量降低了一半,整体功耗得以进一步降低。本文基于低电压低功耗0.7～2.4GHz宽带射频接收前端、四阶复数带通滤波器和限幅放大器完成了整个低电压低功耗无线传感网射频接收链路的设计,着重分析了模块级联、隔离、保护环连接等设计考虑,给出了可以减小芯片键合线影响的一系列措施。测试结果表明该接收链路的性能可以满足WSN系统指标要求。此外,本文根据无线传感网IEEE 802.15.4协议物理层的相关规定对频率综合器的整体指标进行了研究与分析,给出了可以覆盖sub-GHz和2.4GHz多个频段的小数分频频率综合器的系统结构;对环路参数的设计和优化方法进行了研究,并通过行为级仿真对频率综合器的系统功能进行了验证;通过理论分析和推导验证了基于频率综合器的两点注入数字直接调制产生O-QPSK信号的方案可行性,并给出了具体电路实现方法;最后对压控振荡器的设计理论进行了相关研究,给出了低电压低功耗压控振荡器详细的设计和优化方法,并通过流片测试进行了验证。综上所述,本文从系统和模块两个层面对应用于无线传感网的低功耗射频接收关键技术进行了深入的研究,提出了多种低功耗设计和优化方法。虽然本文中研究与分析的芯片都是针对无线传感网IEEE 802.15.4协议进行设计的,但是低功耗射频接收关键技术的研究分析方法和结论同样适用于其它无线通信系统,例如IEEE 802.11、RFID、GPS等等。
[Abstract]:In recent years, with the rapid development of wireless communication systems, all kinds of wireless communication technologies have been widely used in people's daily life. WSN (Wireless Sensor Network) is a research hotspot in the field of information. It is based on data, its network structure is self-organizing and can be dynamically adjusted, and it has very high level. Low power is an important trend in the development of wireless communication systems. Low power RF transceiver is the key to the realization of low power wireless communication systems. Under such application background, low power RF transceiver technology has been proposed and attracted many researchers' attention. Radio frequency transceiver technology is of great theoretical and practical value for promoting the development of wireless communication systems, especially wireless sensor networks. This paper, supported by the National Natural Science Foundation of China, under the support of low power RF transceiver technology research, mainly focuses on the key techniques of low power radio frequency receiving. The IEEE 802.15.4 protocol of wireless sensor network is analyzed, and the structure design of the low power RF transceiver system, the calculation of the overall index, the steps and methods of the module division and link budget are given. The paper makes a paving for the research and design of the circuit module. In this paper, the low noise amplifier (LNA, Low Noise Amplifier), down conversion mixer (Down-conversion Mixer), complex number bandpass filter (CBPF, Complex Band Pass Filter), limiting amplifier (Limiter) and voltage controlled oscillator (VCO, Voltage Control Oscillator) and other key circuit modules have been studied and designed. The CG, Common Gate LNA. paper using the double capacitance cross coupling technique is used to analyze the cause of the error in calculating the noise coefficient in the differential LNA with a cross coupling structure using a half edge equivalent circuit. The direct method is used to solve the noise coefficient of the double capacitance cross coupling CG-LNA. The theoretical derivation shows that the structure is used. The noise coefficient is obviously better than the traditional capacitance cross coupling CG-LNA, and the power consumption is only half of the traditional structure. Finally, a broadband LNA is designed and implemented. The test results of the chip show that the working current of the LNA is 1.0mA, the 3dB bandwidth is 0.5 to 0.95GHz, the electric voltage gain is 20.7dB, and the minimum noise coefficient is 2.8dB. pairs of LN. A has carried out a detailed investigation. On the basis of analyzing the shortcomings of the narrow band LNA circuit such as the source inductance negative feedback common source LNA and other narrow band LNA circuits, this paper presents a 2.4GHz narrow band LNA circuit with multiple transconductance technology at low 1.0V voltage, and gives the specific expression of the input impedance and voltage gain of LNA. The paper emphatically derives the noise coefficient formula of LNA, analyzes the noise optimization process of LNA, and designs a narrow band LNA. under 1.0V power supply voltage, the LNA working current is 0.9mA, its 3dB bandwidth is 2.32 ~ 2.58GHz, the voltage gain is 22.2dB, and the minimum noise coefficient is 4.35dB. with the double capacitance cross coupling CG-LNA and the use of electricity. The Mixer cascade of flow injection technology is designed and implemented. A low power 0.5 to 1GHz wideband RF receiver front end chip is designed to cover the sub-GHz band of the wireless sensor network IEEE 802.15.4 protocol. A low voltage and low power consumption 2.4 is designed and implemented by using the CG-LNA of multiple transconductance lifting technology and the Mixer cascade based on current multiplexing technology. GHz narrow band RF receiver front-end chip. This paper also presents a low voltage and low power 0.7 to 2.4GHz wideband RF receiver front-end circuit based on LNA and Mixer current reuse, and its bandwidth can cover both sub-GHz and 2.4GHz frequency bands in the IEEE 802.15.4 protocol of wireless sensor networks. The results of the design show that the working current of the whole RF receiver is 0.83mA, the voltage gain of the sub-GHz frequency section is 25.0dB, the noise coefficient is less than 6.9dB, 2.4GHz is less than 6.9dB, 2.4GHz. The voltage gain of the frequency band is 18.2dB, and the noise coefficient is less than 10.2dB.. Compared with the previous design, the design has better comprehensive performance. The complex band pass filter in the radio frequency receiving link is studied deeply, the existing circuit structure and the design optimization method are analyzed. Low power consumption, a design method of complex band pass filter based on pole structure is proposed in this paper. The four order plural bandpass filter designed by this method contains 8 differential transconductance units. Compared with the active Gm-C structure based on the two order filter unit, the number of transconductance units is reduced by half and the overall power consumption is further reduced. Based on the low voltage and low power 0.7 ~ 2.4GHz broadband radio frequency receiver front end, the four order plural bandpass filter and the limiting amplifier, the design of the radio frequency receiving link of the whole low voltage and low power wireless sensor network is completed. The design considerations of the module cascade, isolation and protection ring connection are emphatically analyzed, and the influence of the chip bonding line can be reduced. A series of measures. The test results show that the performance of the receiving link can meet the requirements of the WSN system. In addition, this paper studies and analyzes the overall index of the frequency synthesizer according to the relevant regulations of the physical layer of the IEEE 802.15.4 protocol of the wireless sensor network, and gives the frequency division frequency that can cover the multiple bands of sub-GHz and 2.4GHz. The system structure of the synthesizer, the design and optimization method of the loop parameters are studied, and the system function of the frequency synthesizer is verified by the behavior level simulation. The scheme feasibility of the O-QPSK signal based on the two point injection digital direct modulation based on the frequency synthesizer is verified. In the end, the design theory of voltage controlled oscillator is studied, and the detailed design and optimization methods of low voltage and low power voltage controlled oscillator are given and verified by flow sheet test. In summary, the key technology of low power radio frequency receiving for wireless sensor network is corresponded from two aspects of system and module. A variety of low power design and optimization methods are proposed. Although the research and analysis chips in this paper are designed for the wireless sensor network IEEE 802.15.4 protocol, the research and analysis methods and conclusions of the key technologies of low power radio frequency receiving are also applicable to other wireless communication systems, such as IEEE 802.. 11, RFID, GPS and so on.

【学位授予单位】：东南大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TP212.9;TN929.5
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本文编号：1817393