1. Madan Mohan Malaviya University of Technology
Gorakhpur (U.P)
Shreya Tripathi (2021041173)
Bachelor of Technology – 3rd Year
Branch : Electronics and
Communication Engineering
Email: 2021041173@mmmut.ac.in
Fig.1 Broad IoT network
Image Source: https://w3c.social/@w3cdevs/111528162261542565
2. Madan Mohan Malaviya University of Technology Gorakhpur (U.P)
Contents
Introduction
Limitations of IoT devices
RIS assisted localization
Benefits of RIS
System model
Algorithms for RIS-assisted IoT
Conclusion
References
Image Source: https://inno.emsd.gov.hk/en/it-solutions/index_id_79.html
Fig.2 Indoor Localization
3. Madan Mohan Malaviya University of Technology Gorakhpur (U.P)
Introduction
• In various location-based Internet of Things
(IoT) services, it is required to localize a large
number of energy-limited devices
simultaneously and accurately.
• In order to achieve this goal, a
reconfigurable intelligent surface (RIS)-
assisted positioning method for multiple
IoT devices is proposed.
• Here the signals transmitted by the users
reach the base station (BS) along the direct
path and the reflection path via the RIS.
Image Source: https://image.slidesharecdn.com/securityinembeddedsystems-160307143556/75/security-in-embedded-systems-3-
Fig.3 Location-assisted communication in IoT
systems
4. Madan Mohan Malaviya University of Technology Gorakhpur (U.P)
o IoT devices are usually limited in energy yet are
expected to work for a long time after initialization,
which requires proper energy management
mechanisms.
o These devices are also limited in hardware
computation resources to reduce the size, weight,
and cost. Therefore, IoT devices rely on other
network nodes to obtain the location information.
o IoT systems are usually deployed with a massive
amount of low-power and lightweight devices. In
order to provide real-time and high-precision
localization service for the IoT devices, it is
important for the BS to be able to locate multiple
devices simultaneously.
Image Source: https://businessimpactinc.com/wp-content/uploads/2015/04/IoT_purple.jpg:
Limitations of IoT Devices
Fig.4 Applications of IoT
5. Madan Mohan Malaviya University of Technology Gorakhpur (U.P)
A RIS is a metasurface composed of integrated electronic circuits that can be
programmed to modify incoming signals.
RIS is able to redirect the signal propagation by adjusting the phase shifts of the signal-
reflecting elements without dedicated energy sources.
The concept of the reconfigurable intelligent surface (RIS) is of great interest due to its
high efficiency to deliver communication services.
RIS Assisted Localization
Fig.5 Reconfigurable intelligent surface
Image Source: https://w3c.social/@w3cdevs/111528565
6. Madan Mohan Malaviya University of Technology Gorakhpur (U.P)
o RISs can be used to create “smart” environments
capable of selectively blocking or allowing specific
frequencies of signals.
o These could enhance privacy and security by
preventing unauthorized access to wireless
networks.
o RIS could optimize energy consumption in IoT
devices.
o RIS can be configured to operate at any part of
radio spectrum, including frequencies below 6GHz.
o The use of RIS in IoT networks has the potential to
significantly improve energy efficiency.
Image Source: https://businessimpactinc.com/wp-content/uploads/2015/04/IoT_purple.jpg:
Benefits of RIS
Fig.6 Structure of RIS
7. Madan Mohan Malaviya University of Technology Gorakhpur (U.P)
System Model
BS together with its controlling RIS aims to
simultaneously determine the locations of
multiple UEs.
The BS is equipped with the uniform
rectangular array (URA) comprising N = NW
×NL antenna elements.
The RIS consists of M = MW ×ML passive
reflecting elements and is connected to the
BS via a controller.
In this system, the BS determines the
positions of UEs by the principle of
triangulation, where the triangles are formed
by the direct links between the BS and UEs as
well as the reflected links via the RIS.
Image Source: https://image.slidesharecdn.com/presentation-new-160727123330/75/introduction-to-embedded-system-security-11-
Fig.7 Multiuser localization with the aid of RISs
8. Madan Mohan Malaviya University of Technology Gorakhpur (U.P)
Delay Difference
Since the signal sent by each user reaches the BS via two paths with different temporal delays,
the user locations can be inferred by using the delay difference between the direct path and
the reflected path.
Received Signal Strength
Leveraging the signal strength measurements from IoT devices to estimate their positions.
Angle of Arrival
Using the direction of arrival of wireless signals to determine the location of IoT devices.
Time of Arrival
Calculating the time it takes for a signal to travel from the transmitter to the receiver to locate
IoT devices.
Algorithms for RIS-Assisted IoT
9. Madan Mohan Malaviya University of Technology Gorakhpur (U.P)
Conclusion
• Considering the limited power of massively deployed IoT devices, we proposed a RIS-assisted
multiuser positioning method, where a single BS simultaneously localizes the target IoT
devices.
• The variables is optimized including the phase shifts of the RIS elements and the combining
vectors of the BS.
• The total power required to achieve high-precision positioning can be significantly decreased
as the number of RIS elements increases.
10. Madan Mohan Malaviya University of Technology Gorakhpur (U.P)
References
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global navigation satellite systems,” IEEE Trans. Instrum. Meas., vol. 68, no. 12, pp. 4937–4944, Dec. 2019.
[4] Y. Shen, C. Jiang, T. Q. S. Quek, and Y. Ren, “Location-aware device communication design: Exploration and
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[5] J. Talvitie, T. Levanen, M. Koivisto, T. Ihalainen, K. Pajukoski, and M. Valkama, “Positioning and location-aware
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