7,076 research outputs found
A Survey on Wireless Security: Technical Challenges, Recent Advances and Future Trends
This paper examines the security vulnerabilities and threats imposed by the
inherent open nature of wireless communications and to devise efficient defense
mechanisms for improving the wireless network security. We first summarize the
security requirements of wireless networks, including their authenticity,
confidentiality, integrity and availability issues. Next, a comprehensive
overview of security attacks encountered in wireless networks is presented in
view of the network protocol architecture, where the potential security threats
are discussed at each protocol layer. We also provide a survey of the existing
security protocols and algorithms that are adopted in the existing wireless
network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term
evolution (LTE) systems. Then, we discuss the state-of-the-art in
physical-layer security, which is an emerging technique of securing the open
communications environment against eavesdropping attacks at the physical layer.
We also introduce the family of various jamming attacks and their
counter-measures, including the constant jammer, intermittent jammer, reactive
jammer, adaptive jammer and intelligent jammer. Additionally, we discuss the
integration of physical-layer security into existing authentication and
cryptography mechanisms for further securing wireless networks. Finally, some
technical challenges which remain unresolved at the time of writing are
summarized and the future trends in wireless security are discussed.Comment: 36 pages. Accepted to Appear in Proceedings of the IEEE, 201
Survey of Spectrum Sharing for Inter-Technology Coexistence
Increasing capacity demands in emerging wireless technologies are expected to
be met by network densification and spectrum bands open to multiple
technologies. These will, in turn, increase the level of interference and also
result in more complex inter-technology interactions, which will need to be
managed through spectrum sharing mechanisms. Consequently, novel spectrum
sharing mechanisms should be designed to allow spectrum access for multiple
technologies, while efficiently utilizing the spectrum resources overall.
Importantly, it is not trivial to design such efficient mechanisms, not only
due to technical aspects, but also due to regulatory and business model
constraints. In this survey we address spectrum sharing mechanisms for wireless
inter-technology coexistence by means of a technology circle that incorporates
in a unified, system-level view the technical and non-technical aspects. We
thus systematically explore the spectrum sharing design space consisting of
parameters at different layers. Using this framework, we present a literature
review on inter-technology coexistence with a focus on wireless technologies
with equal spectrum access rights, i.e. (i) primary/primary, (ii)
secondary/secondary, and (iii) technologies operating in a spectrum commons.
Moreover, we reflect on our literature review to identify possible spectrum
sharing design solutions and performance evaluation approaches useful for
future coexistence cases. Finally, we discuss spectrum sharing design
challenges and suggest future research directions
JamLab: Augmenting Sensornet Testbeds with Realistic and Controlled Interference Generation
Radio interference drastically affects the performance of sensor-net communications, leading to packet loss and reduced energy-efficiency. As an increasing number of wireless devices operates on the same ISM frequencies, there is a strong need for understanding and debugging the performance of existing sensornet protocols under interference. Doing so requires a low-cost flexible testbed infrastructure that allows the repeatable generation of a wide range of interference patterns. Unfortunately, to date, existing sensornet testbeds lack such capabilities, and do not permit to study easily the coexistence problems between devices sharing the same frequencies. This paper addresses the current lack of such an infrastructure by using off-the-shelf sensor motes to record and playback interference patterns as well as to generate customizable and repeat-able interference in real-time. We propose and develop JamLab: a low-cost infrastructure to augment existing sensornet testbeds with accurate interference generation while limiting the overhead to a simple upload of the appropriate software. We explain how we tackle the hardware limitations and get an accurate measurement and regeneration of interference, and we experimentally evaluate the accuracy of JamLab with respect to time, space, and intensity. We further use JamLab to characterize the impact of interference on sensornet MAC protocols
Energy-Delay Tradeoff and Dynamic Sleep Switching for Bluetooth-Like Body-Area Sensor Networks
Wireless technology enables novel approaches to healthcare, in particular the
remote monitoring of vital signs and other parameters indicative of people's
health. This paper considers a system scenario relevant to such applications,
where a smart-phone acts as a data-collecting hub, gathering data from a number
of wireless-capable body sensors, and relaying them to a healthcare provider
host through standard existing cellular networks. Delay of critical data and
sensors' energy efficiency are both relevant and conflicting issues. Therefore,
it is important to operate the wireless body-area sensor network at some
desired point close to the optimal energy-delay tradeoff curve. This tradeoff
curve is a function of the employed physical-layer protocol: in particular, it
depends on the multiple-access scheme and on the coding and modulation schemes
available. In this work, we consider a protocol closely inspired by the
widely-used Bluetooth standard. First, we consider the calculation of the
minimum energy function, i.e., the minimum sum energy per symbol that
guarantees the stability of all transmission queues in the network. Then, we
apply the general theory developed by Neely to develop a dynamic scheduling
policy that approaches the optimal energy-delay tradeoff for the network at
hand. Finally, we examine the queue dynamics and propose a novel policy that
adaptively switches between connected and disconnected (sleeping) modes. We
demonstrate that the proposed policy can achieve significant gains in the
realistic case where the control "NULL" packets necessary to maintain the
connection alive, have a non-zero energy cost, and the data arrival statistics
corresponding to the sensed physical process are bursty.Comment: Extended version (with proofs details in the Appendix) of a paper
accepted for publication on the IEEE Transactions on Communication
Goodbye, ALOHA!
ยฉ2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.The vision of the Internet of Things (IoT) to interconnect and Internet-connect everyday people, objects, and machines poses new challenges in the design of wireless communication networks. The design of medium access control (MAC) protocols has been traditionally an intense area of research due to their high impact on the overall performance of wireless communications. The majority of research activities in this field deal with different variations of protocols somehow based on ALOHA, either with or without listen before talk, i.e., carrier sensing multiple access. These protocols operate well under low traffic loads and low number of simultaneous devices. However, they suffer from congestion as the traffic load and the number of devices increase. For this reason, unless revisited, the MAC layer can become a bottleneck for the success of the IoT. In this paper, we provide an overview of the existing MAC solutions for the IoT, describing current limitations and envisioned challenges for the near future. Motivated by those, we identify a family of simple algorithms based on distributed queueing (DQ), which can operate for an infinite number of devices generating any traffic load and pattern. A description of the DQ mechanism is provided and most relevant existing studies of DQ applied in different scenarios are described in this paper. In addition, we provide a novel performance evaluation of DQ when applied for the IoT. Finally, a description of the very first demo of DQ for its use in the IoT is also included in this paper.Peer ReviewedPostprint (author's final draft
์ด๊ธฐ์ข IoT ๊ธฐ๊ธฐ๊ฐ ํ๋ ฅ์ ํตํ ๋คํธ์ํฌ ์ฑ๋ฅ ํฅ์
ํ์๋
ผ๋ฌธ(๋ฐ์ฌ) -- ์์ธ๋ํ๊ต๋ํ์ : ๊ณต๊ณผ๋ํ ์ ๊ธฐยท์ ๋ณด๊ณตํ๋ถ, 2022. 8. ๋ฐ์ธ์
.The Internet of Things (IoT) has become a daily life by pioneering applications in various fields. In this dissertation, we consider increasing transmission data rate with energy efficiency, extending transmission coverage with low power, and improving reliability in congested frequency bands as three challenges to expanding IoT applications. We address two issues to overcome these challenges.
First, we design a layered network system with a new structure that combines Bluetooth Low Energy (BLE) and Wi-Fi networks in a multi-hop network. Based on the system, we propose methods to increase data rate with energy efficiency and extend transmission coverage in a low-power situation. We implement the proposed system in the Linux kernel and evaluate the performance through an indoor testbed. As a result, we confirmed that the proposed system supports high data traffic and reduces average power consumption in the testbed compared to the existing single BLE/Wi-Fi ad-hoc network in a multi-hop situation.
Second, we tackle the adaptive frequency hopping (AFH) problem of BLE through cross-technology communication (CTC) and channel weighting. We design the AFH scheme that weights the channels used by BLE devices with improving reliability in the congested bands of both Wi-Fi and BLE devices. We evaluate the proposed scheme through prototype experiments and simulations, confirming that the proposed scheme increases the packet reception rate of BLE in the congested ISM band compared to the existing AFH algorithm.์ฌ๋ฌผ์ธํฐ๋ท์ ํ์ฌ ๋ค์ํ ์์ญ์์ application์ ๊ฐ์ฒํ์ฌ ์ํํ๋์ด ์๋ค. ์ด ํ์ ๋
ผ๋ฌธ์์๋ ์ฌ๋ฌผ์ธํฐ๋ท์ ์์ฉ ์ฌ๋ก ํ์ฅ์ ์ํด ์๋์ง ํจ์จ์ ์ธ ์ ์ก ์๋ ํฅ์, ์ ์ ๋ ฅ ์ํฉ์์์ ์ ์ก ๋ฒ์ ํ์ฅ, ํผ์กํ ๋์ญ์์์ ์ ๋ขฐ์ฑ ํฅ์์ ์๋ก์ด ๋์ ๊ณผ์ ๋ก ์ผ๊ณ , ์ด๋ฌํ ๋์ ๊ณผ์ ๋ฅผ ๊ทน๋ณตํ ๋ ๊ฐ์ง ์ฃผ์ ๋ฅผ ๋ค๋ฃฌ๋ค.
์ฒซ์งธ, ๋ค์ค ํ ๋คํธ์ํฌ ์ํฉ์์์ ๋ธ๋ฃจํฌ์ค ์ ์ ๋ ฅ๊ณผ Wi-Fi ๋คํธ์ํฌ๋ฅผ ๊ฒฐํฉ ํ ์๋ก์ด ๊ตฌ์กฐ์ ๊ณ์ธต์ ๋คํธ์ํฌ ์์คํ
์ ์ค๊ณํ๊ณ ์ด์ ๊ธฐ๋ฐํ ์๋์ง ํจ์จ์ ์ธ ์ ์ก ์๋ ํฅ์ ๋ฐ ์ ์ ๋ ฅ ์ํฉ์์์ ์ ์ก ๋ฒ์ํ์ฅ์ ์ ์ํ๋ค. ์ ์๋ ์์คํ
์ Linux ์ปค๋์ ๊ตฌํํ์ฌ ์ค๋ด ํ
์คํธ๋ฒ ๋๋ฅผ ํตํด ์ฑ๋ฅ์ ํ๊ฐํ๋ค. ๊ฒฐ๊ณผ์ ์ผ๋ก ์ ์ ํ ๊ธฐ๋ฒ์ด ๋ค์ค ํ ์ํฉ์์ ๊ธฐ์กด ๋ธ๋ฃจํฌ์ค ์ ์ ๋ ฅ/Wi-Fi ๋จ์ผ ad-hoc ๋คํธ์ํฌ์ ๋น๊ตํ์ฌ ๋์ ๋ฐ์ดํฐ ํธ๋ํฝ์ ์ง์ํ๋ฉฐ, ํ
์คํธ๋ฒ ๋์์์ ํ๊ท ์ ๋ ฅ ์๋น๋ฅผ ์ค ์ด๋ ๊ฒ์ ํ์ธํ๋ค.
๋์งธ, Cross-technology Communication (CTC)๊ณผ ์ฑ๋ ๊ฐ์ค์น๋ฅผ ํตํ ๋ธ๋ฃจํฌ์ค ์ ์ ๋ ฅ์ Adaptive Frequency Hopping (AFH) ๋ฌธ์ ๋ฅผ ํด๊ฒฐํ๋ค. ์ต์ข
์ ์ผ๋ก ๋ธ๋ฃจํฌ์ค ์ ์ ๋ ฅ ๊ธฐ๊ธฐ๊ฐ ์ฌ์ฉํ๋ ์ฑ๋์ ๊ฐ์ค์น๋ฅผ ๋๋ AFH ๊ธฐ๋ฒ์ ์ค๊ณํ์ฌ Wi-Fi ์ ๋ธ๋ฃจํฌ์ค ์ ์ ๋ ฅ ๊ธฐ๊ธฐ๊ฐ ๋ชจ๋ ํผ์กํ ๋์ญ์์์ ์ ๋ขฐ์ฑ์ ํฅ์ํ๋ค. ํ๋กํ ํ์
์คํ๊ณผ ์๋ฎฌ๋ ์ด์
์ ํตํด ์ ์ํ ๊ธฐ๋ฒ์ด ๊ธฐ์กด์ AFH ๊ธฐ๋ฒ๊ณผ ๋น๊ตํ์ฌ ํผ์กํ ISM ๋์ญ์์ ๋ธ๋ฃจํฌ์ค ์ ์ ๋ ฅ์ ํจํท ์์ ์จ์ ์ฆ๊ฐ์ํค๋ ๊ฒ์ ํ์ธํ๋ค.1 Introduction 1
1.1 Motivation 1
1.2 Contributions and Outline 2
2 Wi-BLE: On Cooperative Operation of Wi-Fi and Bluetooth Low Energy under IPv6 4
2.1 Introduction 4
2.2 Related Work 7
2.2.1 Multihop Connectivity for Wi-Fi or BLE 7
2.2.2 Multi-radio Operation 11
2.3 System Overview 13
2.3.1 Control Plane 13
2.3.2 Data Plane 16
2.3.3 Overall Procedure 16
2.4 MABLE: AODV Routing over BLE 17
2.4.1 BLE Channel Utilization 17
2.4.2 Joint Establishment of Route and Connection 20
2.4.3 Link Quality Metric for BLE Data Channels 22
2.4.4 Bi-directional Route Error Propagation 25
2.5 Wi-BLE: Wi-Fi Ad-hoc over BLE 27
2.5.1 Radio Selection 27
2.5.2 Routing and Radio Wake-up for Wi-Fi 30
2.6 Evaluation 32
2.6.1 BLE Routing 33
2.6.2 Wi-Fi Routing over BLE 35
2.6.3 Radio Selection 38
2.7 Summary 40
3 WBC-AFH: Direct Wi-Fi to BLE Communication based AFH 41
3.1 Introduction 41
3.2 Background 45
3.2.1 Frequency hopping in BLE 45
3.2.2 Cross Technology Communication 47
3.3 Proposed AFH 49
3.3.1 CTC based informing 50
3.3.2 Weighted channel select 51
3.3.3 Hopping set size optimization 52
3.3.4 WBC-AFH 54
3.4 Evaluation 57
3.4.1 Setup 57
3.4.2 Robustness 60
3.4.3 Reliability 61
3.5 Future Work 65
3.6 Summary 66
4 Conclusion 67๋ฐ
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