Transcript Document

Wireless IC Node with
Compression Heuristics
(W.I.N.C.H.)
Final Design Review
Steve Jocke, Kyle Ringgenberg, Stuart Wooters
<scj4s, kringg, wooters>@virginia.edu
System Data Flow Overview
E cycle
avg

PIC Overview
• PIC16C5X.UVa Stats
– 4 Interrupts / 3 Input ports / 5 output ports /
32 Instruction
– Operating voltage of 300mV
– Input clock frequency of 800KHz
• Clock divided down to 200Khz for PIC internal cycles
• Approximately 200 Instructions (I-cycles) between ADC Samples
• System overhead requires approximately 30 I-cycles
– Required to track input values for gain adjustment to ADC
– Leaves ~ 170 I-Cycles free for compression, second core
not required
Run Length Encoding
• Replace Repetition with Occurrence Counts
– Lossless: Only Identical Values Replaced
• 0 0 0 1 3 5 5 6  [3]0 1 3 [2]5 6
– Lossey: Values with a Tolerance Replaced
• 0 0 0 1 3 5 5 6  [4]0 3 [3]5
– Variable Parameters
• Codeword Size – Max Repetition Length
• Block Size – Insert Repetition Code Every Block
– CODE x BLOCK = WORD
• Tolerance – “Stray-ability”
Run Length Encoding
Run Length Encoding
Run Length Encoding
• All Variants Require Additional Repetition
Blocks
• Compression Ratio
– Lossless
• Poor – Worst Case is Worse than Raw
– Lossey
• Excellent – Saturates to Best Compression Ratio
• Executable in O(n)
– 36 Clock Cycles
– 7 Registers
Delta Encoding
• Replace Values with Changes in Values
– Lossless Global: Greatest Δ Dictates Remapping
• 0 0 0 1 3 5 5 6  8x 3-bit “Words”  24 bits
• 0 0 1 2 2 2 1  7x 2-bit “Words”  14 bits
– Lossless Local: Each Δ Treated Independently
• 0 0 1 2 2 2 1  4x 1-bit, 3x 2-bit “Word”  10 bits
• Additional Data for “Word” Lengths
– Lossey Global: Mean Δ Dictates Remapping
• 0 0 1 2 2 2 1  8x 1-bit  8 bits
• Decoded as: 0 0 0 1 2 3 4 5
Delta Encoding
Tightly Clustered
Long Tail
Delta Encoding
Longer Tail, but no Bit Change!
Delta Encoding
3
2.5
2
Raw
deltaG
deltaG'
deltaL
1.5
1
0.5
0
ecg1
ecg2
ecg3
Delta Encoding
• All Variants Require Additional Sign Bit
• Compression Ratio
– Lossless
• Mediocre – Significant Degree of Overhead Bits
– Lossey
• Mediocre – Fidelity is Data Dependent
• Execution in O(n)
– 37 Clock Cycles
– 6 Registers
Compression Conclusions
14
12
10
8
10x
Raw
Lossless
Lossey
6
4
2
0
ecg1
ecg2
ecg3
Mixer Design
Vdd 1.2V
• Active Power:
– 50GHz LO
– 100Mbs
– 9.23mW
• Active Power:
– 1.5 GHz LO
– 100Mbps
– 716.67uW
15GHz Local Oscillator
• Startup Delay:
– 101.626ps
• Startup Power:
– 4.471mW
• Run Power:
– 6.050mW
• Off Power:
– 69.3914μW
LO – 3 Stage Inverter and
Buffer 1.5 GHz
• Startup Time:
– 2.3ns
• Startup Energy:
– 6.92pJ
• Startup Power:
– 3mW
• Avg Power:
– 3.502mW
• Off Power:
– 1.804μW
High Speed Power Examples
•
•
•
•
•
VCO Core: 1mW1 51GHz
Mixer:97mW2 9-50GHz Gilbert Cell
Amplifier 54mW3 60GHz
1.52nJ/bit (100Mbps)
3.04μJ/2Kbit (100Mbps)
1. Tiebout, M.; Wohlmuth, H.-D.; Simburger, W., "A 1V 51GHz fully-integrated VCO in 0.12/spl mu/m CMOS," Solid-State Circuits Conference
, 2002. Digest of Technical Papers. ISSCC. 2002 IEEE International , vol.2, no., pp.238-239, 2002
2. Lin, C.-S.; Wu, P.-S.; Chang, H.-Y.; Wang, H., "A 9-50-GHz Gilbert-cell down-conversion mixer in 0.13-/spl mu/m CMOS technology," Microwave
and Wireless Components Letters, IEEE , vol.16, no.5, pp. 293-295, May 2006
3. Doan, C.H.; Emami, S.; Niknejad, A.M.; Brodersen, R.W., "Millimeter-wave CMOS design," Solid-State Circuits, IEEE Journal of , vol.40, no.1,
pp. 144-155, Jan. 2005
Power Consumption of PIC
(No Compression)
Time μ sec
Power Consumption of PIC
(cont’d)
•
Measurements
–
•
PIC Power Summary
–
–
–
•
Ultrasim Simulator used to measure current
• Set in MS (Mixed Signal / Analog Mode)
Without compression
• 1.) NOP Inst Power 318.1nW (Averaged over 4 NOP’s)
• 2.) AVG Inst Power 322.95nW (All runtime - 2mS)
With compression
• 3.) AVG Inst Power 336.78nW (Over Compression Algorithm)
• 4.) AVG Inst Power 324.46nW (all runtime – 2mS)
Final Stats
• Overall Inst Power 323.7nW
• Delta Power Modes 1.51nW
Conclusion
–
Power Consumption is about the same no matter what operation
• Using free I-cycles recovers wasted power
• Also could throttle back clock frequency
Energy Totals for
Communication Channel
• 15GHz
– On Energy (Mixer + LO):
• 152.8pJ/bit
• 305.6nJ/2Kbit
– Off Power (LO):
• 69.39μW
• 1.5GHz
– On Energy (Mixer + LO):
• 35.06pJ/bit
• 70.1nJ/2Kbit
– Off Power (LO):
• 1.804μW
4. Roving Networks RN-41 V1.5 11/14/07 Documentation
• Bluetooth4
– On Energy:
• 297.5pJ/bit – 165nJ/bit
– Sleep Power
• 825μW
– Idle Power
• 8.25mW
Summary
• Base Case
(Bluetooth)
• Compression (10/1)
– .324nJ/Sample (PIC)
– 2.38nJ/byte (Bluetooth)
– 827nJ/Sample
• No Compression
– .324nJ/Sample (PIC)
– 2.38nJ/byte (Bluetooth)
– 842.4nJ/Sample
• Wireless
• Compression (10/1)
– .324nJ/Sample (PIC)
– 1.224nJ/byte (LO)
– 74.5nJ/Sample
• No Compression
– .324nJ/Sample (PIC)
– 1.224nJ/byte (LO)
– 68.8μJ/Sample