RF Triangulator: Indoor/Outdoor Location Finding 18-525 Architecture Proposal Giovanni Fonseca David Fu Amir Ghiti Stephen Roos Design Manager: Myron Kwai

1
RF Triangulator Indoor/Outdoor Location
Finding 18-525 Architecture Proposal Giovanni
FonsecaDavid FuAmir GhitiStephen RoosDesign
Manager Myron Kwai

• Project Objective
• Design a Radio-Frequency indoor/outdoor
  navigation system, utilizing the existing
  wireless infrastructure.

2
Project Description

• Using existing 802.11 wireless signals it is
  possible to calculate ones location without the
  use of GPS.
• The RF Triangulator will use current
  infrastructures to act as an indoor/outdoor local
  positioning system
• By acquiring signal data from 3 or more wireless
  access points it will be possible to determine
  ones coordinates to within 1 meter.

3
RF Triangulator Applications

• Our chip can be integrated into handheld
  computers, watches, or shopping carts for
  locations ranging from large theme parks to
  office buildings.
• It will be able to quickly provide your current
  location as well as provide a distance and
  heading to a future location for path-finding
  purposes.

4
Triangulation Process

• Our chip will solve for the simultaneous solution
  of 3 circle equations.

5
Major Functional Components

• Top 3 / Queue module
• Gives priority to the top 3 signals based on
  their
• Signal-to-Noise Ratios
• Lookup Table Module
• Hard coded data of MAC addresses, X and Y
  coordinates.
• Calc Module
• Given the coordinates of 3 Access Points and
  their distance, it will calculate the current
  position.

6
Hardware Priority Queuing

• Our chip dynamically sorts the three strongest
  signals in the Top 3 and maintains a queue of
  four more recently used signals.
• Each signal information is the average of the
  last four received signals from that access point
  to prevent random noise to interfere with a
  correct triangulation calculation.

7
Programmable Memory

• An SRAM lookup table stores individual access
  point data including MAC address, X and Y
  coordinates.
• Map information can be loaded into memory
  (off-chip) and as required the chip can load the
  on-chip SRAM with smaller chunks of map
  information.

8
Calc A Custom Datapath

• The calculation requires 1 12-bit FP
  Multiply/Divider, 2 12-bit FP Adders, 1 12-bit
  Comparator, 1 Log Shifter.
• Entire calculation requires 32 cycles, with up to
  four mathematical computations per cycle
  (including data forwarding to save cycles and
  square root approximation).

9
The Computation
10
Design Process

• Original specifications for the chip included
  16-bit floating point calculations and a waypoint
  finder that would calculate distance and
  direction to your desired location.
• Size and complexity constraints reduced floating
  point numbers to 12-bits and eliminated waypoint
  calculation.

11
Floorplan Original Proposal
12
Floorplan Evolution
13
Floorplan Evolution
14
Floorplan Evolution
15
Floorplan Evolution
16
Road to Verification

• Verify Behavior (done)
• Verify Logic (done)
• Verify Schematic (done)
• Verify Layout (in progress)
• Verify Timing (in progress)

17
Specifications

• Total 52,072 transistors
• Top Three 29,322 trans.
• 3 x FPU Add/Sub Units 4500 trans.
• Registers 16104 trans.
• Muxes Computation 8718 trans.
• Calc 19,976 trans.
• 2 x FPU Add/Sub Unit 3000 trans.
• 1 x FPU Mult/Div Unit 5000 trans.
• 1 x Shifter 206 trans.
• 1 x Comparator 800 transistors.
• FSM Logic 1106 transistors
• 25 x 12-bit Registers 6600 trans. total
• 8-1,6-1,4-1,2-1 Mux Sets 3264 trans. total
• Lookup 2,774 trans.
• Control Registers Muxes 2000 trans.
• Control Logic 163 trans.
• Computation 611 trans.
• SRAM 12k trans.
• count not including SRAM, with SRAM 64k

18
Conclusions

• Our project turned out to be much bigger than any
  of us imagined.
• Lots of work to dovery little time.