1. Current Projects Network Coding File System – first NC-based data storage prototype – hold the First Workshop on NC and Data Storage in HK (Jul 21-22, 2011) Physical-Layer Network Coding – first realization on software radio (USRP) Wireless Network Coding Applications – a demo of NC protocol on iPhones BATched Sparse Code (BATS Code) – generalization of fountain code – used in conjunction with network coding – Can out perform fountain code in a multihop network

2. 2 Network Coding File System NCFS: Network-coding-based distributed file system – Use network coding to speed up repair while preserving fault tolerance of storage – No intelligence required on storage nodes – Data is transparently striped across nodes. Clients only see a mount drive NCFS proxy client storage nodes /mnt/ncfs Network

3. 3 Network Coding File System Apply network coding in proxy to improve repair throughput NCFS proxy storage nodes C failed node new node A B C=A+B A B

4. NCDS 2011 First Workshop on Network Coding and Data Storage Hosted by INC Hong Kong, July 21-22, 2011 Free registration http://www.ncds2011.inc.cuhk.edu.hk/

5. Nov 2010Soung Liew, CUHK 5 Traditional Multi-hopping 1 32 S1S1 S1S1 S2S2 S2S2 Time slot 1 Time slot 3 Time slot 2 Time slot 4 Transmissions non-overlapping in time

6. Nov 2010Soung Liew, CUHK 6 Symbol-Level Network Coding 1 32 S1S1 S2S2 Time slot 1 Time slot 3 Time slot 2 Node 3 uses one time slot to broadcast Transmissions by nodes 1 and 2 still non-overlapping

7. Nov 2010Soung Liew, CUHK 7 Physical-Layer Network Coding 1 32 S1S1 S2S2 Time slot 1 Time slot 2 Transmissions by nodes 1 and 2 are simultaneous!

8. Wireless Network Coding Applications

9. Relay Network with Packet Loss

10. BATS Code Network coding at relay (Avalanche) can achieve network capacity asymptotically. Network coding at relay destroys the structure of the fountain code, i.e., fast decoding not possible. BATS code, a generalization of fountain code, provides a solution. Advantages of BATS code: – achieve network capacity asymptotically – no delay at relay – fast encoding and decoding, like fountain code