videos for project demonstration are also available upon request.

1. Indoor Wireless Localization
Name: Ali Reda Salim
In Collaboration with: Mohmamad Assaad, Daylight Katengwe
Supervisor: Zihuai Lin

2. Presentation Outline
•What is Indoor Wireless Localization and its
applications
•Previous research & bottlenecks
•Our system design & approach
•Analysis & Results
•Demonstration Video
•Conclusion & Future Work

3. Indoor Wireless localization
•GPS is a hug success and generated billions of
dollars in revenues.
•Worked seamlessly within line of sight (outdoor)
•GPS signals can’t penetrate walls and solid concrete
•The evolution of low cost wireless sensors permitted
solutions for indoor positioning.
• low cost 802.15.4 Zigbee compliant nodes to
implement our proposed design.

4. Indoor Wireless localization
Applications
•Tracking local assets
•Medical applications
•Internet of things
•Emergency rescue operations
•Commercial & business uses
•Location based services

5. Indoor Wireless localization
•Previous papers used RSSI claim an accuracy of 1-
1.5m
•Other researchers relied on TOF & TDOA and claim
an accuracy of almost 2m.
•Above algorithms rely on RSSI, time stamps and
node synchronization
•Most papers used Zigbee compliant stacks and
extracted the required metrics from network and
application layers

6. TIMAC Protocol Stack
• OSAL & HAL layers to access
lower layers
• HAL layer provides a broad
range services
Z-Stack Protocol Stack
• Z-Stack provides access to
upper layers
• ZMAC Interface to access
MAC layer
Approach

7. 802.15.4 MAC API
• Initialization
• Data
• Management
• Call-back
Approach
HAL API
• Provides functions to access
the hardware services like
timers, UART, and ADC.
• Separates the hardware from
the software specific
LCD Service
HALLCDINIT() Initiate LCD screen on-board
HALLCDWRITESTRING() Write strings to the screen
HALLCDWRITESTRINGVA
LUE()
Write strings and values to the
screen
KEY Service
HALKEYINIT() Initiate Key & Joystick on-board
HALKEYCONFIG() Configure Keys operation
Timer Service
HalTimerInit () Initiate timer services on-board
HalTimerConfig() Configure and pre-scale timers
halTimerIntEnable();
UART Service
HALUARTINIT () Initiate Serial port on-board
HALUARTOPEN () Open a serial port
HALUARTWRITE () Write strings and values to
serial port
Function/Event Description Prototype
MAC_CbackEvent
( )
Call back function sends
MAC events to the
application layer
void
MAC_CbackEvent(macCbac
kEvent_t *pData)
MAC_MCPS_DAT
A_IND
An event called by the call
back function and sends data
to app
macDataInd_t *pDataInd
MAC_MCPS_DAT
A_CNF
An event that sends data to
app each time the
MAC_McpsDataReq function
is called
macMcpsDataCnf_t
*pDataCnf

8. System Design
• TI CC2530 development kit
• 802.15.4, HAL & OSAL API’s
• TIMAC Sample Application
• Modification of TIMAC protocol
stack to support timer services
• Integrating few Z-stack
functions into MAC Sample
application

9. System Design
• Hardware timestamp stored in 40-bit register
upon transmit/receive of frames
• Average signal strength measured by reading
the 8 symbols after the SFD domain
• RSSI and Correlation values
• Data output to I/O devices

10. Analysis & Results
• Point to point network
• Frame transmission Interval set to 5 seconds
• Transmit and received frames sent to serial port
• Clock drifts calculated between transmission
and receive time of various frames

11. 175
180
185
190
195
200
205
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49
RSSI Readings
(Line of Sight vs Non Line of Sight)
C23 D22
150
155
160
165
170
175
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47
RSSI Mid Range
(Non line of Sight)
Series1 Series2 Series3
0
50
100
150
200
250
300
1 5 9 13 17 21 25 29 33 37 41 45 49 53 57 61 65 69 73 77 81 85 89 93
Sci-Tech Libary Readings
(Mobile Node)
RSSI Corr
Analysis & Results

12. Analysis & Results
• 3 static node & 1 mobile
node
• RSSI values collected
from each node & sent to
serial port
• MATLAB simulations
triggered by the serial
input
• Estimated mobile node
location within an
accuracy of 1-1.5m

13. Video Demonstration

14. Conclusion
•Integration of Z-Stack & TIMAC software protocols.
•A new approach to provide reliable & accurate
metrics to any localization algorithm
•Access of lower layers
•Low Local clock speeds
•Synchronization problems
•Reliable RSSI & Correlation readings
•Accuracy of almost 1m using just signal strength and
correlation values

15. Future Work
•Implement smoothing techniques on local clock to
minimize the effect of clock drift
• Linear smoothing using linear regression to align local
clock readings between 2 different nodes
•Use external high speed clocks or nodes with higher local
clocks
•Synchronization of nodes wirelessly
•Use antenna diversity to have more accurate RSSI
readings
•Ultra-wide band can be used instead of narrow band
signals like Zigbee (5Mhz)

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