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Muriel Medard - Network Coding in Satellites - Global SIP 2018
- 1. Private and Confidentialcodeontechnologies.com Network Coding in Satellites Muriel Medard
- 2. Private and Confidential Presentationby Muriel Medard @ 27 November, Anaheim, California 2018 IEEE Global Conference on Signal and Information Processing 2
- 3. Private and Confidential Satellitein 5G Not just point to point 3
- 4. Private and Confidential RLNCBackground Coding Landscape 4 Block Codes Convolutional Codes Rateless Codes Raptor and related codes • Rate-less (refinement to free E2E) • Still E2E, still static Network Codes • RLNC enables network coding • Deterministic construction for special cases • Index Coding • CATWOMAN (Linux 3.10) Point-to-Point (PtP) Point-to-Multi-Point (PtMP) Network Code 1960s 1950s 1998 2003 Modern Codes • LDPCs • Turbo Codes • Polar Codes 1990 to 2010
- 5. Private and Confidential RLNCbasics Beyond point to point 5
- 6. Private and Confidential Whereto code Different possibilities 6
- 7. Private and Confidential Satellitepoint-to-point Improving throughput 7
- 8. Private and Confidential RLNCfor throughput Allow more errors At the PHY Error-rate performance (AWGN channel) for RS codes (255, 239, 17) and (255, 223, 33) in red, along with PHY and Effective RLNC Error Rates with {0.5, 1, 1.5, 2, 2.5, 3}. Note that the cost of extra redundancy is taken into account through a shift in Eb/No level, whereas throughput is kept constant. “RLNC as a Network-Layer Code A study of RLNC as a complement to physical-layer coding” CodeOn White Paper Feb 2018 8
- 9. Private and Confidential RLNCat transport Integrating with TCP J. K. Sundararajan, Shah, D., Médard, M., Jakubczak, S., Mitzenmacher, M. and Barros, J., “Network Coding Meets TCP: Theory and Implementation”, invited paper, Proceedings of the IEEE, March 2011, pp. 490 – 512 9
- 10. Private and Confidential Slidingwindow Structure would be prohibitive 10
- 11. Private and Confidential TCPwithout coding Window ceases to progress TCPsender window p1 p2 p3 p4 p1 p2 p3 ACK(p1) ACK(p1) p2 p3 p4 p5 p5 ACK(p1) p2 p3 p4 ACK(p1) receiver M. Kim, Cloud, J., ParandehGheibi, A., Urbina, L., Fouli, K., Leith, D., and Médard, M., “Congestion Control for Coded Transport Layers”, IEEE ICC Communication QoS, Reliability and Modeling Symposium 2014 11
- 12. Private and Confidential TCPwith coding Window continues to progress Prevents random losses being interpreted as congestion Coded TCPsender window p1 p2 p3 p4 Σp SEEN(1) SEEN(2) p4 p5 p6 p7 SEEN(4) SEEN(5) SEEN(6) Σp Σp Σp Σp Σp Σp SEEN(3) p7 p8 p9 p10 p11 SEEN(7) Σp p8 p9 p10 p11 p12 receiver 12
- 13. Private and Confidential Thefour phases of queue oscillation 1. Sat gate queue not full. TCP senders receive ACKs, increase congestion window. Queue builds up. 2. Sat gate queue full. New packets arriving are dropped. Senders still receive ACKs and send more data in the direction of the queue. Queue continues to overflow: burst losses 3. ACKs from dropped packets become overdue. Senders throttle back. Packet arrival at queue slows to a trickle. Queue drains. 4. Queue clears completely. Link sits idle for part of the time, link not fully utilized Note: Queue oscillation explains the packet loss phenomena on all sat links we studied U. Speidel, L. Qian, ’E. Cocker, P. Vingelmann, J. Heide, M. Médard, “Can Network Coding Mitigate TCP-induced Queue Oscillation on Narrowband Satellite Links?”, International Conference on Wireless and Satellite Systems, 301–314, Springer International Publishing, July 2015 13
- 14. Private and Confidential Transportneeds to be adapted to high RTT Simple modification 0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0 1 2 3 4 5 6 7 x 10 6 PER Goodput(bps) CTCPv1 CTCPv2 HTCP Cubic Hybla Reno Veno Westwood Rate = 10 Mbps, RTT = 500 ms J. Cloud, Leith, D, and Médard, M. “Network Coded TCP (TCP) Performance over Satellite Networks”, SPACOMM 2014 14
- 15. Private and Confidential RLNCfor Satellite in the Pacific 15 • O3b satellite connection • Typical peak time link utilization around 50% • TCP/NC encoders/decoders in Avarua and Auckland • g=30, overhead variable based on feedback • TCP/NC running alongside standard TCP • Would probably need less overhead if all connections were coded Rarotonga U. Speidel, Cocker, ‘E., Vingelmann, P., Heide, J., and Médard, M., “Can Network Coding Bridge the Digital Divide in the Pacific?”, Netcod 2015 U. Speidel, Cocker, ‘E., Médard, M., Heide, J., amd Vingelmann, P., “Topologies for the Provision of Network-Coded Services via Shared Satellite Channels”, SPACOMM 2017 (Winner Best Paper Award)
- 16. Private and Confidential RLNCfor Satellite in the Pacific Funafuti, Tuvalu 16 • GEO downlink (16 Mbps) • TCP supported by SilverPeak accelerator • Very low link utilization below 25% TCP/NC maintains steady goodput with 1-10% packet loss TCP/NC can complete some downloads even with >10% packet loss U. Spiedel, Cocker, ‘E., Vingelmann, P., Heide, J., and Médard, M., “Can Network Coding Bridge the Digital Divide in the Pacific?”, Netcod 2015 P. Vingelmann, J. Heide, M. Médard, “Can Network Coding Mitigate TCP- induced Queue Oscillation on Narrowband Satellite Links?, International Conference on Wireless and Satellite Systems, 2015 U. Speidel, Cocker, ‘E., Médard, M., Heide, J., amd Vingelmann, P., “Topologies for the Provision of Network-Coded Services via Shared Satellite Channels”, SPACOMM 2017 TCP/NC experiments Graphic: own measurement
- 17. Private and Confidential Whichlayer? Can do both 17
- 18. Private and Confidential Codingand delay Packet reception time 18 J. Cloud, D. Leith, and M. Médard, “A Coded Generalization of Selective Repeat ARQ”, INFOCOM 2015 M. Karzand, Leith, D., Cloud, J., and Médard, M., “Design of FEC for Low Delay in 5G”, IEEE Journal of Selected Areas in Communication, Vol. 35, No. 8, Aug. 2017, pp. 1783- 1793
- 19. Private and Confidential Codingand delay Packet reception time 19 J. Cloud, D. Leith, and M. Médard, “A Coded Generalization of Selective Repeat ARQ”, INFOCOM 2015 (RLNC)
- 20. Private and Confidential Inorder decoded delay Gains and tuning 20
- 21. Private and Confidential Broadcast Transmissionto multiple end users 21
- 22. Private and Confidential Satellitebroadcast with feedback TDD dofs to decode: dofs to decode: dofs to decode:Rx 1 Rx 2 Rx N Tx M packets M M M dofs = degrees of freedom D. Lucani, Médard, M., and Stojanovic, M., “On Coding for Delay - Network Coding for Time Division Duplexing”, IEEE Transactions on Information Theory, vol. 58, no. 4, April 2012, pp. 2330 - 2348 22
- 23. Private and Confidential Satellitebroadcast with feedback TDD 23 10 -3 10 -2 10 -1 0.3 0.4 0.5 0.6 MeanCompletionTime(s) (a) 10 -3 10 -2 10 -1 10 0 10 1 10 2 Packet Erasure Probability NumberofCodedPackets (b) Broadcast TDD Optimal Broadcast TDD Worst Link Channel Broadcast TDD Combined Erasure Effect Broadcast TDD Optimal Broadcast TDD Worst Link Channel Broadcast TDD Combined Erasure Effect N1 N5
- 24. Private and Confidential Satellitebroadcast with feedback TDD 2424 Full Duplex Broadcast using Round Robin: Tx Rxi 1 …2 3 1M ACK 2 3 i-th Channel 1 3 M 3 TDD Broadcast using Round Robin: Tx Rxi 1 2 3 ACK i-th Channel 9 M
- 25. Private and Confidential Satellitebroadcast with feedback TDD 2525 10 -3 10 -2 10 -1 10 0 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Packet Erasure Probability MeanCompletionTime(s) Optimal Broadcast with Network Coding TDD Broadcast Round-Robin (RR) TDD Broadcast RR Full Duplex (Upper Bound) Broadcast RR Full Duplex (Lower Bound) •Outperforms TDD constrained Round Robin broadcast scheme (optimal, no coding) •For high erasure probability: Outperforms full duplex Round Robin broadcast
- 26. Private and Confidential Multiplepaths Difficulty without coding 26
- 27. Private and Confidential Multiplepaths Keeping track of packets IP flow 1 IP flow 2 Application layer IP flow 1 IP flow 2 Application layer Server Client Lte NIC WiFi NIC Block i Block i Divide & Schedule Combine Media player p1p2p3 … pw p1p2p3 … pw p1p2p3 … pw Block 1 Block 2 Block 3 … … Request block i Media file: p1 p3 p5 p2 p4 p6 J. Cloud, du Pin Calmon, F., Zeng, W., Pau, G., Zeger, L., and Médard, M., “Multi-Path TCP with Network Coding for Mobile Devices in Heterogeneous Networks”, VTC 2013 27
- 28. Private and Confidential Multiplepaths Keeping track of packets IP flow 1 IP flow 2 Application layer IP flow 1 IP flow 2 Application layer Server Client Lte NIC WiFi NIC Block i Block i Divide & Schedule Combine Media player p1p2p3 … pw p1p2p3 … pw p1p2p3 … pw Block 1 Block 2 Block 3 … … Request block i Media file: p1+p4 p2+p3 p1+p5 p2+p4 p3+p6 p4+p5 28
- 29. Private and Confidential MTP/NC Codingover multiple paths All packets within the MPTCP/NC coding window are coded together and pushed to different sub- flows Application MPTCP/NC TCP TCP Fast- TCP/NC Fast- TCP/NC IP IP NETWORK Network Interface Network Interface Application MPTCP/NC TCP TCP Fast- TCP/NC Fast- TCP/NC IP IP Network Interface Network Interface Network Coding and Reliable Communications Group 29
- 30. Private and Confidential MTP/NC Codingover multiple paths All received packets are ACK’ed All packets within the MPTCP/NC coding window are coded together and pushed to different sub- flows Each packet from TCP generates R linearly independent coded packets where each packet is generated from the set of packets within the TCP window Application MPTCP/NC TCP TCP Fast- TCP/NC Fast- TCP/NC IP IP NETWORK Network Interface Network Interface Application MPTCP/NC TCP TCP Fast- TCP/NC Fast- TCP/NC IP IP Network Interface Network Interface Each received packet is immediately forwarded to the TCP layer Network Coding and Reliable Communications Group 30
- 31. Private and Confidential MTP/NC Codingover multiple paths All received packets are ACK’ed All packets within the MPTCP/NC coding window are coded together and pushed to different sub- flows Each packet from TCP generates R linearly independent coded packets where each packet is generated from the set of packets within the TCP window Application MPTCP/NC TCP TCP Fast- TCP/NC Fast- TCP/NC IP IP NETWORK Network Interface Network Interface Application MPTCP/NC TCP TCP Fast- TCP/NC Fast- TCP/NC IP IP Network Interface Network Interface MPTCP/NC layer ACKs all new degrees of freedom received Decoding only occurs at the MPTCP/NC layer Each received packet is immediately forwarded to the TCP layer Network Coding and Reliable Communications Group 31
- 32. Private and Confidential MTP/NC Differentdelays log 10 (File Size) Averagecompletiontime(ms) Link 1: RTT =1500ms p = 10−3 Link 2: RTT =80ms p = 10−2 3 4 5 6 10 2 10 3 10 4 10 5 10 6 10 7 10 8 Uncoded Coded, R=(1−p)−1 Coded, R=1.05(1−p)−1 log(File Size) AverageRate(packet/s) Link 1: RTT =1500ms p = 10−3 Link 2: RTT =80ms p = 10−2 3 4 5 6 0 200 400 600 800 1000 1200 1400 Uncoded Coded, R=(1−p)−1 Coded, R=1.05(1−p)−1 Time (s) Jointwindowwize(packets) Link 1: RTT=1500ms, p = 10−2 Link 2: RTT=80ms, p = 10−1 0 10 20 30 40 50 60 70 0 50 100 150 200 250 Coded, R=(1−p)−1 Coded, R=1.05(1−p)−1 Uncoded X X Network Coding and Reliable Communications Group 32
- 33. Private and Confidential MTP/NC Differentdelays log(File Size) AverageRate(packet/s) Link 1: RTT =1500ms p = 10−3 Link 2: RTT =15ms p = 10−2 3 4 5 6 0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000 Uncoded Coded, R=(1−p)−1 Coded, R=1.05(1−p)−1 log10 (File Size) Averagecompletiontime(ms) Link 1: RTT =1500ms p = 10−3 Link 2: RTT =15ms p = 10−2 3 4 5 6 10 2 10 3 10 4 10 5 10 6 10 7 10 8 Uncoded Coded, R=(1−p)−1 Coded, R=1.05(1−p)−1 Time (s) Jointwindowwize(packets) Link 1: RTT=1500ms, p = 10−3 Link 2: RTT=15ms, p = 0.3 0 5 10 15 20 0 20 40 60 80 100 120 140 160 180 200 Coded, R=(1−p)−1 Coded, R=1.05(1−p)−1 Uncoded X X Network Coding and Reliable Communications Group 33
- 34. Private and Confidential Recoding Noneed to decode CODING THE NETWORK: NEXT GENERATION CODING FOR FLEXIBLE NETWORK OPERATION IEEE CTN Issue: July 2018 K. Fouli, M. Medard, K. Shroff 34
- 35. Private and Confidential Recoding Noability to decode Packet reception time 35
- 36. Private and Confidential SatelliteContext Multiple Relevant Topologies 36 Brunel.ac.uk Mobile Mesh F. Vieira et al., Satcom 2011 Multipath Multicast Multipath Heterogeneous Multi-hop Multi-hop kddi.com
- 37. Private and Confidential Recodingwith losses Different losses 1 2 4 sender From given data receiver Recoding at intermediate nodes, without decoding 37 3
- 38. Private and Confidential Recodingwith losses Different losses TCP End-to-end coding Re-encoding at node 3 only 0.0042 Mbps 0.1420 Mbps 0.2448 Mbps (assuming each link has a bandwidth of 1 Mbps in the absence of erasures) Time average throughput (over 641 seconds) 38
- 39. Private and Confidential Satellitein 5G Not just point to point 39
- 40. Private and Confidential Futureaspects • Recoding at satellite • Edge caching with coding • On-the-ground peer-assisted satellite content delivery • Coding for multi-beam • Multi-sourcing with satellite • Secure coding Coding throughout 40
- 41. Private and Confidential41 This document was created by Code On Network Coding LLC (“Code On”), a limited liability company based in Cambridge, MA, with registered offices at One Broadway, Floor 14, Cambridge, Massachusetts, 02142. All rights thereto are owned and reserved by Code On. This strictly private and confidential document was prepared exclusively for information purposes only and for discussion. This document is incomplete without reference to–and should be viewed solely in conjunction with–the oral presentation provided by Code On. While all reasonable care has been taken to ensure that the facts stated herein and in the accompanying oral presentation are accurate and that the opinions contained herein and in such presentation are fair and reasonable, the information provided is selective in nature and is intended to serve as an introduction and overview of, the content described herein. Any opinions expressed in this document and/or the accompanying presentation is subject to change without notice and neither Code On nor any other person is under any obligation to update or keep current such information. No representation, undertaking, promise or warranty, express or implied, is or will be made, or given as to, and no responsibility or liability is or will be accepted by Code On, its respective directors, officers, agents or employees in relation to the adequacy, accuracy, completeness or reasonableness of this document or any other information (whether written or oral), notice or document supplied or otherwise made available to any third or their respective advisers in connection with this document. This document and the information provided in the accompanying presentation is confidential and of a proprietary nature. This document may not be reproduced or redistributed outside the recipient's organisation or publicised in whole or in part for any purpose, including to the press or any media organization, without the express prior written consent of Code On. No right or entitlement to an implementation of the presentation or the concepts presented herein arises from this document and/or the presentation. Disclaimer