(A) study on low power transceiver for bluetooth low energy 4.2/5.0 dual mode applications

Lee, Dongsoo Sungkyunkwan university 2018 국내박사

This dissertation presents a low power GFSK transceiver with high efficiency power management unit and integrated SPDT switch for Bluetooth low energy application. It is implemented with the RF front-end with an inductor-less LNTA and 25% duty-cycle current-driven passive mixers, and low IF baseband analog with complex BPF to reduce power consumption and area, and improve image rejection ratio, respectively. In the analog PLL, low power VCO is designed using Automatic Bandwidth Calibration (ABC) is proposed to optimize bandwidth, settling time, and phase noise by adjusting the charge pump current, VCO gain, and resistor and capacitor values of the loop filter. Current consumption of the ADC is reduced by adopting straightforward architecture. To ensure the proposed low power transceiver can operate at the data rate of 1Mbps and 2 Mbps for support BLE 4.2 and 5.0, GFSK modulation is implemented using an Analog PLL with ABC. The DC-DC buck converter improves overall efficiency by automatically selecting optimum mode among triple modes, PWM, PFM, and retention, depending on load current. Low noise LDO is designed to improve receiver sensitivity and phase noise of VCO. The transceiver is implemented using 1P6M 55-nm CMOS technology and the die area is 1.79 mm2. Power consumption of the receiver and transmitter are 5 mW and 6 mW from the supply voltage of 3 V, respectively. Noise Figure of the receiver is up to 6.5 dB with respect to channel frequencies. Measured sensitivity is -95 dBm at 2.44 GHz. The measured phase noise of the PLL is -87.1 and -112.2 dBc/Hz at 100 kHz and 1 MHz offset from 2.44 GHz in the receiver mode, respectively. Efficiency of the DC-DC Buck converter is over 89% when the load current is higher than 2.5 mA in the PWM mode. Quiescent current consumption of the transceiver is 400 nA from supply voltage of 3 V in the retention mode.

(A) study on frequency synthesizer with two point modulation for bluetooth low energy application

박종진 성균관대학교 일반대학원 2021 국내석사

본 논문에서는 Bluetooth Low Energy 4.2 / 5.0 어플리케이션을 위해 설계된 저전력 주파수 합성기의 설계 이슈와 절차에 대한 연구 내용이다. 주파수 합성기는 Phase Locked Loop 기반으로 설계 되었으며, 1 Point Modulation 과 2 Point Modulation 을 선택적으로 사용할 수 있도록 설계되었다. 2 장에서 PLL, VCO, 2 Point Modulation 의 기본 이론에 대해 설명하고, 3 장에서 PLL Sub Block 과 2 Point Modulation 의 주요 설계 이슈와 과정, 그리고 핵심 아이디어에 대해 설명한다. PLL 은 저전력 설계를 기본으로 하여 CP 의 전류, VCO 의 Gain 및 Loop Parameter 를 조절하여 Bandwidth, Lock Time, Phase Noise 를 최적화하였다. 또한 2 Point Modulation 의 정확한 동작을 위한 Calibration 을 하는데, 이를 디지털로 동작하도록 설계하였다. 제안하는 주파수 합성기는 TSMC 55 nm CMOS 공정으로 설계 되었다. This paper present design issues and procedures for low-power frequency synthesizers designed for Bluetooth Low Energy 4.2/ 5.0 applications. The frequency synthesizer is designed based on Phase Locked Loop and is designed to selectively use 1 Point Modulation and 2 Point Modulation. Chapter 2 discusses the basic theory of PLL, VCO, and 2 Point Modulation, and Chapter 3 describes the main design issues and processes of PLL Sub Block and 2 Point Modulation, as well as key ideas. Based on the low-power design, PLL optimizes Bandwidth, Lock Time, and Phase Noise by adjusting the current, VCO's Gain, and Loop Parameters. It also performs calibration for accurate operation of 2 Point Modulation, which is designed to work digitally. The proposed frequency synthesizer is designed using TSMC 55 nm CMOS process.

BLE connectivity and its multi-hop extension for IoT applications

이태섭 서울대학교 2017 국내박사

Bluetooth Low Energy (BLE) is one of the representative low-power communication protocols that are being used to provide wireless connectivity for resource constrained devices as part of Internet of Things (IoT). Despite its commercial adoption, BLE's current use is limited to short-range applications due to the lack of research about its coverage extension. In this dissertation, we investigate two issues that need to be addressed for BLE's network coverage extension and also consider a new application scenario using a BLE-based multi-hop network. First, we tackle the BLE connection maintenance and energy consumption problems by adaptively controlling one of BLE's link layer parameters (TCI ) under dynamic channel condition. We formulate an optimization problem to find an optimal TCI and design a connection interval adaptation mechanism for BLE to achieve high energy efficiency while maintaining robust connectivity. We evaluate our proposed solutions through testbed experiments and simulation which shows that it reduces energy consumption of BLE in dynamic channel environments. Secondly, we consider a protocol architecture that aims to run IPv6 routing protocol for low power and lossy networks (RPL) over BLE to construct BLE-based multi-hop networks. We design an adaptation layer between BLE and RPL which tightly couples RPL and BLE operation. We implement the adaptation layer in a Linux kernel to realize RPL over BLE. Through extensive experiments in an indoor testbed, we evaluate the performance of RPL over BLE and compare the performance results with that of RPL over IEEE 802.15.4 which shows signicant improvement. Lastly, we consider a new application scenario of BLE using the coverage extension of BLE based on multi-hop networking. We propose a novel layered architecture of Wi-Fi and BLE that constructs an energy efficient and high data rate supportable ad-hoc network for disaster communication. We implement the proposed architecture in Linux kernel and evaluate the performance through our indoor testbed. The result shows that our proposed solution reduces the average power consumption of nodes in the testbed compared to a conventional Wi-Fi ad-hoc network.

A study for the construction of large-scale, low-power wireless sensor networks

방재석 서울대학교 대학원 2023 국내박사

The arrival of the Internet of Things (IoT) era has opened a new way of living by connecting the physical and the virtual domains as a single domain. Wireless sensor networks (WSNs) may play a key role for combining the two domains in a very efficient manner. A number of technologies have been developed for the deployment of WSNs, in consideration of IoT services in various operation environments. The primary concern on WSN operation is the provision of connectivity that can provide reliable and seamless communications among devices. ZigBee and Bluetooth Low Energy (BLE), low-power connectivity technologies, have widely been applied to IoT services. However, they may not provide desired performance when applied to large-scale IoT service environments. It is of great concern to develop wireless connectivity technologies that can provide desired performance in commercial IoT service environments. In this dissertation, we consider low-power connectivity technologies in large-scale IoT service environments. We first investigate the connectivity problem of legacy ZigBee in a multi-hop tree-structured networking configuration that may not provide full connectivity in large-scale environments. We may improve the connectivity problem by focusing on device selection and resource allocation for routers. We make devices join the network as an end device in the first stage. Then, parent devices convert some of their child end devices to their child router devices in consideration of geographical network expansion. The resource is allocated to routers in consideration of data traffic and addressing parameters, improving the throughput and latency performance, while preserving the network scalability. We also investigate the connectivity of BLE with adaptive frequency hopping in the presence of co-channel interference (CCI). We consider the reduction of time for the detection of CCI by means of channel grouping, where devices operate using a single channel group in the normal operation. Upon the detection of severe CCI, the devices may operate using multiple channel groups to find a channel group least affected by CCI. By fast detecting severe CCI and fast investigating the frequency band, the proposed scheme may maintain connectivity even in presence of rapidly time-varying CCI. Finally, we verify the proposed schemes by means of extensive computer simulation and hardware implementation. The proposed schemes can significantly enhance the connectivity of ZigBee and BLE, improving the scalability, latency, memory footprint and power consumption. 사물인터넷 (IoT)의 도래로, 물리적인 영역과 가상적인 영역을 하나로 연결하는 새로운 패러다임을 이끌어내고 있다. 무선 센서 네트워크(WSN)는 이 두 가지 영역을 매우 효율적으로 결합하는 데 중요한 역할을 할 수 있다. 이러한 역할 때문에, WSN은 다양한 IoT 서비스 운용 환경에서 연결성, 즉, 기기 간 안정적이고 원활한 통신을 제공할 수 있어야 한다. ZigBee와 Bluetooth Low Energy (BLE) 같은 저전력 연결 기술들이 널리 IoT 서비스에 적용되어 왔지만, 대규모 IoT 서비스 환경에서 상용화 가능한 수준의 연결성을 제공하지 못하고 있다. 본 논문은 대규모, 저전력 무선 센서 네트워크에서의 원활한 연결성을 제공하는 네트워킹 기술을 다룬다. 우선, 대규모 네트워크에서 완전한 연결성을 제공하기 어려운, 기존 ZigBee의 다중 홉 트리 구조의 네트워킹 기술을 자녀 선택과 라우터에 대한 자원 할당에 초점을 맞추어 개선한다. 제안 기술은 우선적으로 기기들을 종단 기기로 네트워크에 가입시킨 후, 네트워크를 확장하기에 적합한 일부의 기기를 선택하여 라우터로 전환한다. 또한 데이터 트래픽과 주소 파라미터를 고려하여 라우터에 자원을 할당함으로써 쓰루풋(throughput)과 전송 지연 성능을 개선하는 한편, 네트워크의 확장성은 유지한다. 본 논문은 동일 채널 간섭이 존재하는 환경에서 적응적 주파수 도약(adaptive frequency hopping)을 사용한 BLE의 연결성 문제도 고려한다. 제안 기술은 채널 그룹화를 통해 간섭 신호 감지 시간을 단축시킨다. 기기들은 일반 운용(normal operation) 시 하나의 채널 그룹만 사용하여 동작하고, 심한 간섭 신호가 검출되면, 여러 개의 채널 그룹을 사용함으로써 간섭 신호가 더 적은 채널 그룹을 찾을 수 있다. 간섭 신호를 빠르게 검출하고 검출 즉시 전 주파수 대역을 조사함으로써, 제안 기술은 빠르게 시변(時變)하는 간섭 신호가 존재하는 환경에서도 연결성을 유지할 수 있다. 본 논문은 컴퓨터 시뮬레이션과 하드웨어 구현을 통해 제안 기술을 검증한다. 제안 기술은 메모리 사용량 및 전력 소비를 철저히 고려하여 실제 구현이 가능하게끔 설계되었으며, ZigBee와 BLE의 연결성을 현저하게 향상시킬 수 있다.

쿼드러처 저잡음 증폭기를 사용한 저전력 2.4GHz BLE 수신기의 설계

박범유 강원대학교 대학원 2021 국내석사

블루투스 용 저전력 ADPLL을 위한 시간-디지털 변환기의 설계

김우섭 성균관대학교 일반대학원 2017 국내석사

최근 Wearable Device, Internet of Things (IoT) 등의 분야에 대한 관심과 기대가 지속적으로 증가하고 있으며 그 중 Bluetooth는 IoT분야의 다양한 곳에 응용 가능한 단거리 무선통신 기술이다. 현재는 기존의 Bluetooth에서 소모전력의 단점을 개선한 Bluetooth Low Energy (BLE) 기술이 주목 받고 있으며, 이에 따라 송수신 회로 내에서 중요한 역할을 하는 Phase Locked Loop (PLL)의 중요성 또한 주목 받고 있다. BLE의 주요 특성은 저전력으로 이를 향상시키기 위하여 Sub-micron 공정에서 기존 Analog로 설계되던 PLL을 Digital로 구현하려는 연구가 많이 진행되어 왔다. 이러한 All Digital Phase Locked Loop (ADPLL)에서 In-band의 Phase Noise를 결정하는데 중요한 역할을 하는 것이 Time to Digital Converter(TDC)이다. 따라서 본 논문에서는 Bluetooth Low Energy (BLE) Application에 사용 가능한 ADPLL에서 중요 Block 중 하나인 TDC와 TDC의 Cover range를 결정하게 되는 Retimer를 제안한다. 본 논문에서는 BLE용 저전력 ADPLL을 위한 TDC는 55nm CMOS 공정으로 설계 되었다.

Development of the encryption algorithm for prevention hacking of Beacon

김재형 성균관대학교 일반대학원 2015 국내석사

ICT technology is the communication environment that is already generalized in the current smart media environment of using smart device. The appearance of IoT(Internet of Things) is leading to being formed the communication environment that connects humans, things and spaces in the more organic form. Especially, the advent of bluetooth 4.0 LE method led to allowing the next-generation IoT technology called beacon to be paid attention by industry. It is available for enjoying in the device that is applied BLE(Bluetooth Low Energy). However, the development in information technology caused a lot of damage such as privacy invasion and information leakage. Bluetooth, which is used in many devices, is a representative example out of IoT technology. It is found hacking cases using hacking tools such as BlueSnarf, BlueBug, and BlueJack. The damage of using this is being diversely shown such as communication disruption and data delete including simple pop-up message transfer. The purpose of this study is to design encryption algorithm in order to intensify a security element of utilizing beacon service using bluetooth. The authentication between server and user was allowed to be analyzed by implementing service and producing application through the connection between beacon and server. Also, to remove time error between server and beacon device, it designed in order to be available for the initialization in the inside of application. Performance was identified by generating algorithm of utilizing MD5 hash function, personal identification code(password), current time and by developing prototype for analyzing this.

저전력 블루투스에서 안전 응용을 위한 CSMA 성능 향상 기법

박형철 경북대학교 대학원 2018 국내석사

Recently, the number of accidents between pedestrian and personal mobility is increasing year after year as the use of personal mobility is increasing. Due to the technological advancement, personal mobility with high speed is being invented even with a small labor. Furthermore, electric personal mobility using battery and electric motors has appeared. Nowadays, use of personal mobility is becoming a trend. There are electric wheel, electric bicycle and electric scooter. In the case of electric wheel, the movement speed can be up to 30 km/h. In the case of electric bicycle, the speed can be up to 35 km/h. Due to this reason accidents between pedestrians and personal mobility are very dangerous. In recent years, research of communication-based safety application has been actively pursued to prevent such accidents. Previously I have proposed Bluetooth Low Energy (BLE) based safety application. In that proposed scheme three channels are used for the communication in BLE, and as it is asynchronous communication the reliability of safety application decreases. There can be high packet collision when there are multiple senders existing nearby. This also makes the reliability of safety application to be decreased. Moreover, as BLE devices send packets based on pure ALOHA there is a high possibility of packet collision. Therefore, in this paper, enhanced CSMA (Carrier Sense Multiple Access) is proposed to improve the reliability of communication-based safety application using BLE. Furthermore, I also analyze the performance of existing scheme in BLE, existing CSMA and proposed enhanced CSMA through experiments using NS-3 (Network Simulator 3).

Extending Bluetooth LE for Mutual Discovery in Massive IoT Environments

Sangrok Han 고려대학교 대학원 2020 국내박사

Bluetooth Low Energy (BLE) is probably the best technological tool that we can harness today for studies on close human interactions. It has a wide deployment base (i.e., on smartphones), has peer discovery as an inherent protocol feature, does not require infrastructure (e.g. satellites or base stations) to operate, and sparingly uses energy that is good for extended monitoring. In this dissertation, we show that we can use the BLE peer discovery capability on smartphones to detect and monitor massive and dynamic encounters, which would provide valuable insights into many epidemiological or sociological phenomena. However, being designed for more leisurely interactions, BLE needs some stretching in order to be used in large-scale operations. Specifically, the protocol design is not optimal to rapidly discover hundreds of devices in the communication range, whereas dense crowds and mass gatherings are not unrealistic in city life. Moreover, if the crowd is dynamic, discovery becomes even more time-pressed because encounters should be recorded before churn. In this dissertation, we push the BLE technology with the requirements to discover hundreds of devices before co-presence expires, and to work continually over a typical smartphone charge cycle. Specifically, we investigate how we should modify the BLE protocol and how we should set its protocol parameters for this purpose. We show that with the proposed changes and configurations, we can accelerate the speed of discovery for massive and dynamic crowds by more than an order of magnitude compared to the case that we naively follow the guidance of the current BLE standard.

(A) study on low power BLE advertising transmitter for tag IC applications

Kim, Donggyu Sungkyunkwan University 2024 국내박사

This paper proposes a low-power Gaussian frequency-shift keying (GFSK) transmitter for Bluetooth low energy (BLE) advertising. The proposed transmitter is composed of an analog phase-locked loop (PLL) that performs open-loop modulation and a power amplifier, which are optimized for the BLE advertising mode, where the transmitter turns on for a short period of time to transmit data and then turns off. The analog PLL that performs open-loop modulation first generates the target frequency output from a voltage-controlled oscillator (VCO) in a closed-loop mode with negative feedback. The control voltage of the VCO at this time is stored in a capacitor and input to the VCO through a buffer in the subsequent open-loop mode. The output frequency offset caused by the control voltage offset, which can be caused by the offset of the buffer, the clock feed-through of the switch, etc., is measured using a counter and compensated using the modulation capacitor bank of the VCO. No additional circuitry is used to detect and compensate for the frequency offset, so the area does not increase and the power consumption is reduced by the amount of power consumed by the divider, phase-frequency detector, and charge pump that operated for negative feedback. The proposed power amplifier is implemented to ensure distortion-free spectrum radiation mask performance by smoothly increasing the output power from the minimum power to the maximum power after it starts operating, so that there is no sudden change in the output power. The proposed analog PLL that performs open-loop modulation consumes 600 µA less current than closed-loop modulation, consumes 1.1 mW of power at a supply voltage of 0.8 V, and the power amplifier consumes 4.9 mW of power. The chip area is 1.17 mm² and the 55 nm CMOS process is used. The measurement results confirmed that the offset occurring in open-loop modulation is compensated. 본 논문은 태그 IC용 Bluetooth low energy (BLE) advertising을 위한 저전력 Gaussian frequency-shift keying (GFSK) 송신기를 제안한다. 제안하는 송신기는 일정한 시간마다 켜진 후 짧은 시간 동안 데이터를 송신하고 다시 꺼지는 BLE advertising 방식에 특화되어 전력 소모를 최소화할 수 있는 열린 루프 변조를 수행하는 아날로그 위상동기루프와 구동증폭기로 구성되어 있다. 열린 루프 변조를 수행하는 아날로그 위상동기루프는 먼저 부정 피드백을 사용하는 닫힌 루프 모드에서 전압 제어 발진기로 목표 주파수의 출력을 생성하고 이때의 전압 제어 발진기의 제어 전압은 커패시터에 저장되어 이어지는 열린 루프 모드에서 버퍼를 통해 전압 제어 발진기에 입력된다. 버퍼의 오프셋, 스위치의 clock feed-through 등으로 발생할 수 있는 제어 전압 오프셋으로 인한 출력 주파수 오프셋은 카운터를 사용하여 측정되고 전압 제어 발진기의 변조 커패시터 뱅크를 사용하여 보정된다. 주파수 오프셋을 감지하고 보상하기 위한 목적으로 추가적인 회로를 사용하지 않아 면적이 증가하지 않고 소모 전력은 부정 피드백을 위해 동작하였던 분주기, 위상-주파수 검출기, 차지펌프의 소모 전력만큼 줄어들게 된다. 제안하는 구동증폭기는 왜곡 없는 스펙트럼 방사 마스크 성능을 위해 동작이 시작된 뒤 최소 파워부터 최대 파워까지 출력 파워가 부드럽게 증가해 급격한 출력 파워 변화가 발생하지 않도록 구현되었다. 제안된 열린 루프 변조를 수행하는 아날로그 위상동기루프는 닫힌 루프 변조일 때보다 600 µA 더 적은 전류가 흐르며 0.8 V의 공급전압에서 1.1 mW의 전력을 소모하고 구동증폭기는 4.9 mw의 전력을 소모한다. 칩의 면적은 1.17 mm²이며 55 nm CMOS 공정을 사용하였다. 측정 결과 열린 루프 변조에서 발생하는 오프셋이 보정되는 것을 확인 하였다.