1. Low-Density Parity-Check Codes (LDPC Codes)
Speaker : 施 信 毓 (Genius)
Advisor : Prof. Andy Wu
Date : 2008/01/22

2. Outline Digital Communication System Low-Density Parity-Check Codes
Our Outstanding Achievements
Learning Target & Schedule
Needed Background
Conclusion

3. Digital Communication SystemTx
BPSK, QPSK,
16-QAM, 64-QAM
JPEG, MPEG
LDPC codes
Information
Source
Channel
Modulator
Source
Encoder
Encoder
Noise
Channel
Channel Rx
Source
Channel
Data Sink
Demodulator
Decoder
Decoder

4. Why Do We Need the Channel Coding?!
Interference/Noise
Channel
Z z Z

5. Low-Density Parity-Check Codes
Parity check matrix : sparse matrix
Bipartite graph B1 B2 B3 B4 B5 B6 B7 B8 B9 C1 C2 C3 C4 C5 C6
Bit nodes
(columns) B1 B2 B3 B4 B5 B6 B7 B8 B9
Check nodes
(rows) C1 C2 C3 C4 C5 C6

6. Error Correction Ability
LDPC
Encoder
LDPC
Decoder
Channel (AWGN)
Iterative process

7. Pros and Cons Pros : Cons : Applications : (IEEE std)
Best error correction ability in the coding world
Highly parallel decoding scheme
Cons :
Higher area cost
(Routing complexity)
Higher power consumption
Applications : (IEEE std)
Mobile WiMAX (802.16e)
Wi-Fi (802.11n)
10G over Copper (802.3an)
BER
Eb/N0

8. Our Outstanding Achievements
Paper Lists :
2007 IEEE Symposium on VLSI Circuits (SOVC) –
“A 19-mode 8.29mm2 52-mW LDPC Decoder Chip for IEEE e System” .
IEEE Journal of Solid-State Circuits (JSSC) –
“An 8.29mm2 52mW Multi-mode LDPC Decoder Design for Mobile WiMAX System in 0.13um CMOS Process” .
Awards :
94學年度台大電子所最佳碩士論文獎
2007台大電子所學生傑出研究獎
2007國家系統晶片設計中心(CIC)優良晶片設計獎
2007第七屆旺宏金矽獎--設計組優勝獎
2007第二屆鳳凰盃IC設計競賽--數位IC設計組優等獎

9. Learning Target & Schedule
Time
week
Simple introduction of communication system
Design concept of channel coding
Encoding algorithm of LDPC codes
Decoding algorithm of LDPC codes
Paper reading (2~3 papers)
Floating-point simulation of SPA & MSA (C/C++)
Fixed-point simulation of SPA & MSA (C/C++)
Future work : (Maybe in next semester)
(1) Hardware architecture / (2) Decoding algorithm

10. Needed Background Conclusion Enthusiastic Hard-working attitude
Software coding skill
Professional background (optional)
Conclusion
Learning the most powerful channel coding in the communication system
Develop your software coding skill (C/C++)
No pains, no gains