1 / 18

THE PERSPECTIVES OF MULTITHRESHOLD DECODERS APPLICATION IN HIGH SPEED COMMUNICATION SYSTEMS

THE PERSPECTIVES OF MULTITHRESHOLD DECODERS APPLICATION IN HIGH SPEED COMMUNICATION SYSTEMS. Zolotarev V.V., Ovechkin G.V . Space Research Institute RAS, Russia The Ryazan state radio engineering academy Conference « Networks and communication system - 200 5 ».

colorado-whitley
Download Presentation

THE PERSPECTIVES OF MULTITHRESHOLD DECODERS APPLICATION IN HIGH SPEED COMMUNICATION SYSTEMS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. THE PERSPECTIVES OF MULTITHRESHOLD DECODERS APPLICATION IN HIGH SPEED COMMUNICATION SYSTEMS Zolotarev V.V., Ovechkin G.V. Space Research Institute RAS, Russia The Ryazan state radio engineering academy Conference «Networks and communication system - 2005»

  2. A coding is consist in the introducing of redundancyinto a transmitted message A using of error-correction codes is one of major methods for decreasing of bit error probability in the communication systems r –parity bits k – information bits + n = k + r – code length R=k / n– code rate (the part of information bits in transmitted message) Zolotarev, Ovechkin

  3. THE MAIN ADVANTEGES OF USING ERROR-CORRECTING CODES The using of error-correcting codes allows to get a coding gain, each decibel of which is estimated in millions dollars. The coding gain is used for: • decreasing transmitter power; • increasing speed of data transfer; • decreasing size of antennas; • increasing range of communication; • decreasing used bandwidth; • work over more noisy channels. Zolotarev, Ovechkin

  4. WHAT KIND OF CODES IS NEED TO BE USED? Codes is need be • long; • accepted to low cost and effective decoding. Zolotarev, Ovechkin

  5. THE BIT ERROR RATE FOR OPTIMAL DECODING BLOCK CODES VERSUS CHANNEL BIT ERROR RATE OVER A BINARY SYMMETRIC CHANNEL Zolotarev, Ovechkin

  6. THE MOST EFFECTIVE CODES AND DECODING METHODS IS • Viterby decoder; • Reed-Solomon code and short convolutional code decoding with the Viterby decoder; • turbo convolutional codes; • turbo product codes; • low-density parity-check codes; • repeat-accumulate codes; • product-accumulate codes; • multithreshold decoders. Zolotarev, Ovechkin

  7. THRESHOLD DECODER Diagram of encoder for convolutional code withR=1/2 andd=5. Diagram of threshold decoder for convolutional code withR=1/2 andd=5. Threshold decoder is very simple scheme for error correction, but it’s efficiency is too low. Zolotarev, Ovechkin

  8. THRESHOLD DECODER Zolotarev, Ovechkin

  9. MULTITHRESHOLD DECODER Multithreshold decoder (MTD) is the development of an ordinary threshold decoder. In MTD for the first time effective iterative decoding method is used, which later applied for turbo codes decoding. MTD during decoding can many times change of received information bits and so can attain an optimal decoder decision with linear complexity. Zolotarev, Ovechkin

  10. MULTITHRESHOLD DECODER Diagram of multithreshold decoder with two decoding iterations for convolutional code withR=1/2 andd=5 The main property of MTD– with each change of an information bit the decision of MTD is approach to an optimal decoder decision Zolotarev, Ovechkin

  11. MULTITHRESHOLD DECODER PERFORMANCE OVER AN AWGN CHANNEL Zolotarev, Ovechkin

  12. PERFORMANCE OF CONCATENATED SCHEME BASED ON MULTITHRESHOLD DECODER OVER AN AWGN CHANNEL Zolotarev, Ovechkin

  13. SOFTWARE IMPLEMENTATION OF MULTITHRESHOLD DECODER 1. The complexity of software implementation: NMTD=(I+1)(d+2) additive equivalent operations on an information bit,whereIisiterations number and discode distance. 2. MTD is applicable for codes withd<20 and needs about 10-20 decoding iterations. 3. It’s possible to low operations number to about NМПД=4d+3I operations.It is much less than turbo codes decoder complexity! Zolotarev, Ovechkin

  14. SOFTWARE COPMLEXITY COMPARISON Number of operations on an information bit areneeded for achieving bit error rate of 10-5 MTD is in 10 or more times less complex than other methods for error correcting with comparable efficiency Zolotarev, Ovechkin

  15. HARDWARE IMPLEMENTATION OF MULTITHRESHOLD DECODER 1. MTD consists of memory elements or shift registers. They are the fastest elements in PLIS or BIS.The part of other elements in MTD is less than 1%. 2. MTD consists of 3 - 40 work in parallel shift registers and single-cycle threshold elements. That’s why the complexity of MTD implemented on PLIS is in 100 and more times faster than, for example, turbo codes decoder. 3. Characteristics of MTD codec implemented on PLIS:- information speedisabout 160 - 480 Mbpsand more, - coding gainisabout 6,5 - 8,5 dB. Zolotarev, Ovechkin

  16. PHOTO OF MULTITHRESHOLD DECODER IMPLEMENTED ON PLIS XILINX Zolotarev, Ovechkin

  17. PERFORMANCE OF MULTITHRESHOLD DECODER IMPLEMENTED ON PLIS XILINX Zolotarev, Ovechkin

  18. CONTACT INFORMATION Zolotarev Valery Vla18dimirovich Phone: (095) 333-23-56, (095) 261-54-44 Mobile: +7-916-518-86-28 e-mail: zolotasd@yandex.ru Ovechkin Gennady Vladimirovich Phone: (0912) 92-00-56 Mobile: +7-910-644-51-46 e-mail: g_ovechkin@mail.ru web-site: www.mtdbest.iki.rssi.ru Zolotarev, Ovechkin

More Related