1. PBCC-22 Chris Heegard, Ph.D.,
Sean Coffey, Ph.D., Anuj Batra, Ph.D., Srikanth Gummadi and Matthew Shoemake, Ph.D. Home and Wireless Networking
Texas Instruments
141 Stony Circle, Suite 130
Santa Rosa California
(707) ,
PBCC-22

2. Outline History Discovery of a New Code
PBCC-22 Properties and Performance
Conclusion
PBCC-22

3. Short History of PBCC Alantro Communications incorporated, August 1997
Blending the Theory of Information with the Art of Silicon
PBCC-11 introduced in IEEE
64 State Binary Convolutional Code + Signal Scrambler
Introduced in March 1998 meeting
Adapted as “High Performance” option
Although it provided a more robust solution, +3dB C.G., it was deemed “too complex”
Time to market was a major factor in selection of CCK
Harris semiconductor had a working MBOK chip
PBCC-22

4. Movitation for Higher Performance
PBCC-22

5. History (cont) PBCC-22 developed beginning in summer of 1998
Constraints
Interoperability with IEEE b networks
Translate coding gain advantage to “double the data rate”
22 Mbps
Compatibility with IEEE b radios
8-PSK, 11 MHz symbol rate, short preamble
Operate in the same environment as CCK-11
64 state code --->> 256 state code
A good engineering solution: cost versus performance
Satisfy FCC Requirements
PBCC-22

6. Discovery of a New Code Problem: Find optimal
(k=2, n = 3) 256 state code matched to 8PSK
Solution discovered in January 1999
The new code has many interesting features
Optimal Distance Spectrum for 8-PSK
Optimal Free Distance in many scenarios
8-PSK, Digital-8PSK
Hamming distance (Binary coding)
Underboeck 8-way partition (Trellis Coded QAM)
PBCC-22

7. Packet Binary Convolutional Coding
Combines Binary Convolutional Coding with Codeword Scrambling
PBCC-22Rate k=2, n=3 encoder
256 state
Digital-8PSK modulation
Dfree^2/Es = 704/98 = 8.6 dB
Reference: 16QAM+Interleaved (k=1,n=2) 64 state BCC
Dfree^2/Es = 40/10 = 6.0 dB (-2.6 dB)
PBCC-22

8. PBCC Components
PBCC-22

9. BCC Encoder for 22Mbps
PBCC-22:
PBCC-22

10. The “s” Sequence
A length 256 sequence generated from a length 16 sequence
[c0,c1,…,c15] = [ ]
Periodically extended for >256
PBCC-22

11. Digital 8-PSK
PBCC-22

12. Distance Bound 350 360 370 380 390 400 10 20 30 40 50 Distance10 20 30 40 50
Distance
Average Number
Cumulative Distribution with Upper Bound
Number of States: 256 G:
450
500
100
200
300
600
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13. Average Distance Spectrum
350
360
370
380
390
400 1 2 3 4 5 6 7 8
Distance
Average Number
Distance Spectrum with Cumulative Distribution
Number of States: 256 G:
PBCC-22

14. AWGN Performance
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15. PBCC-22

16. PBCC-22

17. Conclusions PBCC is an innovative new code that solves a real problem
Backward compatible with IEEE b standard
Backward compatible with radio and regulatory requirements
“Doubles the Data Rate” in the same environment
Patent pending
PBCC-22