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Copy of Overview of Current Indoor Positioning Systems

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manali Shah

on 25 April 2014

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Transcript of Copy of Overview of Current Indoor Positioning Systems

GPS is also referred as Outdoor Positioning.
Pinpoints an individual within approximately 20 meters.
Applications :
1.Road Navigation
2.Photo tagging
3.Location based Searches
4.In defense systems, for tracking missiles and enemy

GPS fails indoors.
GPS requires an unobstructed view to orbiting satellites in order to compute position. (LOS)
Signals sent by GPS satellites are relatively weak and can't penetrate through buildings.
What is
Indoor Positioning?
Indoor Positioning
System which attempts to provide an accurate position inside a covered structure, such as an Airport, a Subway, or a Mall.
This is done using Triangulation where location will be calculated mathematically by approximating signal propagation and finding distance from anchors.
Uses - preventing theft of expensive devices, guiding the users in museums, finding books in large libraries based on their location and the location of products in a supermarket, location detection of firemen etc.
WiFi Triangulation
Wireless networks have become more popular in recent years and are set up in universities, shopping malls, hospitals etc.
Using this existing wireless network infrastructure we can keep track of expensive devices or persons by using received signal strength values.
How it works :
> WPS uses the signal of WLAN access point to determine the position of mobile user.
> The signal strength values from the reference station (access points) are measured by the positioning device.
> In 802.11 signal environment, the signal strength will be location sensitive, which means that the changes between mobile devices and access point base stations, the signal strength change accordingly.
Existing Systems
Cisco MSE (Mobile Services Engine):
It can determine the location of any wireless device in the building.
The access points themselves listen for the Wi-Fi signals created by your phone, and then estimate its position via triangulation.
This solution has been deployed successfully at a few locations, including at the American Museum of Natural History.
Euclid Zero :
It gives retailers, malls, and other venues customer insights and answers from their existing Wi-Fi access points.
Retailers can access actionable insights for improving shopper engagement, loyalty, and revenue, all through Euclid's easy-to-use web-based dashboard.

Issues In Existing Systems
Signal strength depends on environment, furniture, temperature, total number of people etc.
Secondly, sensor positioning needs to be determined so that the client is always in vicinity of 3 or more sensors and within acceptable distance so that we can perform triangulation.
There will be sensors which fail regularly and will end up receiving data from less than 3 sensors.
Also most of the existing system are not secure and they are vulnerable to most of the malicious attacks.
Proposed System
Two types of communication :
1. Node to Base Station
2. Base Station to Database Server
Since these communications take place in an open environment malicious packet injection is easy in these networks.
It is essential to have a robust authentication protocol that keeps the system secure against attacks like Man-in-the-Middle, Replay, Cloning and Dos attacks.
Wi-Fi triangulation, Positioning and Authentication
Manali D. Shah
Shrenik N. Gala
Project Guide: Dr. Narendra M. Shekokar
Proposed Protocol
When communication takes place in this system either from Node to Base Station or from Base Station to Database Server it must be sure that data is only from the claimed node and not from any attacker.
Having these considerations, the proposed protocol proposes a method of combining congruence based technique with Fermat number theory for authenticating both types of communication and usage of Fermat number theory with the circular convolution product of sequences for authenticating communication.

Today usage
Shopping Malls
Firefighters localization
Encryption Algorithm
Minimum Computation
No Key Exchange ALgorithm
Maintains Secrecy
Security Attacks
The proposed authentication protocol can withstand several security attacks on the system:
1. Man-in-the-Middle attack

The proposed protocol explains why man-in-the-middle attack is not successful, because the exclusive secret key is unidentified by the attacker. Hence, it will be unable to generate the hash using the random number. Thus no vital information can be extracted from a packet capture.
2. Replay Attack
In our proposed protocol, a nonce is generated each time and is attached to the message. The nonce is in the form of timestamp which will make each message unique and data freshness is maintained. The intruder will not be able to request with some old message because it can't match with the previous timestamp which is maintained at each node. Hence, the replay attack is impossible.
3. Denial of Service (Dos)
According to the proposed protocol after receiving instant request, authentication is done and since buffer is not needed and possibility of fake messages is nil, DoS attacks are impossible.
4. Cloning attack
In our protocol, a cloned node will not be able to generate fake requests since a node capture does not reveal any useful information. This is due to the use of CRT that stores the secret key exclusively in the Base Station.
Authentication at Sensor Nodes
Notations Explanation
DBpi, Npi Relative prime numbers in DB Server and Nodes
DBri , Nri Relative residues in DB Server and Nodes
E Encryption Function
D Decryption Function
X,H Two k-bit random numbers
X[n],H[n] Two sequences of length N generated from X,H
Ft Fermat Number
FNT Fermat Number Transform
IFNT Inverse Fermat Number Transform

Base Station
Efficiency Analysis
Congruence equaltion is constructed combining secret key and Mac M.
So single congruence equation will have a single solution.
Hence, a node capture will immediately expose the secret key.
Proposed Protocol :
One prime value and residue is stored, resulting in multiple solutions, making it impossible to compute one correct solution.

Light Wieght
Instant Authentication
Minimum memory utilization
Protection against attacks
Maintains data integrity and confidentiality
Thank You!
Nri mod Npi,
Dri mod Dpi

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