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SECURE SATELLITE COMMUNICATIONS IN NETWORK CENTRIC OPERATIONS

SECURE SATELLITE COMMUNICATIONS IN NETWORK CENTRIC OPERATIONS. Sorin Adrian Barbulescu University of South Australia Nghia H. Ngo Somnomedical Pty Ltd Oana Cristina Barbulescu PricewaterhouseCoopers CIS2010, Los Angeles, USA. Turbo Encoding Turbo Decoding Examples.

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SECURE SATELLITE COMMUNICATIONS IN NETWORK CENTRIC OPERATIONS

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  1. SECURE SATELLITE COMMUNICATIONS • IN NETWORK CENTRIC OPERATIONS Sorin Adrian Barbulescu University of South Australia • Nghia H. Ngo • Somnomedical Pty Ltd • Oana Cristina Barbulescu • PricewaterhouseCoopers • CIS2010, Los Angeles, USA

  2. Turbo EncodingTurbo Decoding Examples Source Encoder – eliminates redundancy Encryption function – increases uncertainty ENC function – “Efficient Node Coding” Encoder – optimizes redundancy ENC solution – Turbo Codes Channel Encoder – adds redundancy

  3. Turbo EncodingTurbo Decoding Examples The encoder is made of shift registers and memory: very fast, very low complexity, very low power!

  4. Turbo EncodingTurbo Decoding Examples Turbo Codes achieve Shannon capacity ! IPN Progress Report 42-151

  5. Turbo EncodingTurbo Decoding Examples The interleavercan be any size and can be changed at any time! Switch! For an interleaver of size 106 bits there are 10300 combinations... Designed and controlled by the user! Non-linear Interleaver Generator

  6. Turbo EncodingTurbo Decoding Examples • 16QAM equiprobable modulation Q (cos) +3 The ordinary way +1 I (sin) -3 -1 +1 +3 -1 -3

  7. Turbo EncodingTurbo Decoding Examples 16QAM non-equiprobable constellation The smarter way

  8. Turbo EncodingTurbo Decoding Examples 256QAM non-equiprobable constellation for a non-linear satellite channel Ideal Channel Real Channel

  9. Turbo Encoding Turbo Decoding Examples The decoder doesn’t work if the interleaving and mapping functions aren’t known ! There is no ciphertext for the cryptanalyst to work on!

  10. Turbo Encoding Turbo Decoding Examples If the interleaver is not known, the received data is useless! The interleavercan be changed in a pseudo random way!

  11. Turbo Encoding Turbo Decoding Examples Multi-User Detection (MUD) technology Targeted new markets: remote sensor networks with tens or hundreds of simultaneous transmitters

  12. Turbo Encoding Turbo Decoding Examples Shannon’s Separation Principle: independent source and channel coding is optimum! • Assumption: • the information sequence length goes to infinity which in turns implies: • infinite delay and • infinite complexity. Not valid assumptions in the real world!

  13. JPEG/MPEG Encoder Turbo Encoder Modulator Wireless Channel JPEG/MPEG Decoder Turbo Decoder Demodulator iterative decoding Turbo Encoding Turbo Decoding Examples In the case of separate source and channel coding, residual channel errors lead to error propagation in the decryptor block or the source decoder. Reversible Variable Length Code Solution: use joint source channel codec!

  14. Turbo Encoding Turbo Decoding Examples Secure Satellite Communications • no extra cost • no extra delay • no extra resources • traffic optimization • works with PEPs

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