Project Objective:

1. RF Triangulator: Indoor/Outdoor Location Finding18-525 Architecture ProposalGiovanni 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 one’s 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 one’s 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 • Area: 750x680 square microns • Density: 0.102 trans/sq. micron

18. Conclusions • Our project turned out to be much bigger than any of us imagined. • Lots of work to do…very little time.