+ Post New Thread
Results 1 to 13 of 13
  1. #1
    Junior Member level 3
    Points: 1,171, Level: 7

    Join Date
    Jul 2008
    Posts
    29
    Helped
    1 / 1
    Points
    1,171
    Level
    7

    What exactly is precoding and what does it do?

    What is precoding? Can anyone explain me or give me a link to provide a fundamental knowledge on precoding please.
    Thank you.

    •   AltAdvertisment

        
       

  2. #2
    Full Member level 1
    Points: 1,810, Level: 9
    senaydud's Avatar
    Join Date
    Jun 2008
    Posts
    112
    Helped
    32 / 32
    Points
    1,810
    Level
    9

    what is precoder

    I have checked the wikipedia "http://en.wikipedia.org/wiki/Precoding", it says that it is related to Beamforming & MIMO. does everyone think so?



  3. #3
    Member level 1
    Points: 1,770, Level: 9
    gaffar's Avatar
    Join Date
    Jul 2006
    Location
    Turkey
    Posts
    32
    Helped
    19 / 19
    Points
    1,770
    Level
    9

    channel precoder

    Precoding is a technique which exploits transmit diversity by weighting information stream, i.e. the transmitter send the coded information to the receiver in order to the pre-knowledge of the channel. The receiver is a simple detector, such as matched filter, and does not have to know the channel side information. This technique will reduce the corrupted effect of communication channel.

    For example you are sending information, s
    and it will pass through the channel, h
    and Gaussian noise, n
    The received signal at receiver front-end will be, r=sh+n;

    The receiver will have to know the information about h and n. It will supress the effect of n by increasing SNR but what about h? It need information about the channel, h and this will increase the complexity. The receiver, mobile units, have to be simple for many reasons like cost, size of mobile unit. So, the transmitter, base station, will do the hard work and predicts the channel.

    Let call the predicted channel, h_est
    and for a system with precoder the information will be coded, s/h_est
    and the received signal will be, r=(h/h_est)s+n

    if your prediction is perfect, h_est=h, and r=s+n, and it turns out to be the detection problem in Gaussian channels which is simple.



  4. #4
    Full Member level 1
    Points: 1,810, Level: 9
    senaydud's Avatar
    Join Date
    Jun 2008
    Posts
    112
    Helped
    32 / 32
    Points
    1,810
    Level
    9

    need of precoding

    So why do they call it "coding"? what you explain sounds much like "equalization at the transmitter".



  5. #5
    Member level 1
    Points: 1,770, Level: 9
    gaffar's Avatar
    Join Date
    Jul 2006
    Location
    Turkey
    Posts
    32
    Helped
    19 / 19
    Points
    1,770
    Level
    9

    precoding fundamental

    It is a preprocessing technique that performs transmit diversity and it is similar to equalization but the main difference is you have to optimize precoder with a decoder. Channel equalization aims to minimize channel errors, but precoder aims to minimize the error in the receiver output.



  6. #6
    Member level 5
    Points: 1,330, Level: 8

    Join Date
    Jun 2008
    Posts
    80
    Helped
    9 / 9
    Points
    1,330
    Level
    8

    precoder wikipedia

    usually transmitter does not know about channel, if there is a feedback than transmitter will get a information about the channel by adaptive filter.

    The adaptive coading at the transimitter will be done in this way. This is called precoading of the signal at the transmitter



    •   AltAdvertisment

        
       

  7. #7
    Member level 1
    Points: 1,770, Level: 9
    gaffar's Avatar
    Join Date
    Jul 2006
    Location
    Turkey
    Posts
    32
    Helped
    19 / 19
    Points
    1,770
    Level
    9

    common precoder

    By using pilot-assisted techniques, transmitter will have ability to predict the channel without feedback. It is called forward error control, and precoding is a technique of forward error control.


    1 members found this post helpful.

  8. #8
    Newbie level 4
    Points: 1,113, Level: 7

    Join Date
    Dec 2006
    Posts
    6
    Helped
    2 / 2
    Points
    1,113
    Level
    7

    precoding book

    Quote Originally Posted by ks1267
    What is precoding? Can anyone explain me or give me a link to provide a fundamental knowledge on precoding please.
    Thank you.
    I have some works about precoding over MIMO channels. If you need tell me.


    1 members found this post helpful.

  9. #9
    Junior Member level 3
    Points: 1,171, Level: 7

    Join Date
    Jul 2008
    Posts
    29
    Helped
    1 / 1
    Points
    1,171
    Level
    7

    common precoder

    Quote Originally Posted by ahmad_1024
    Quote Originally Posted by ks1267
    What is precoding? Can anyone explain me or give me a link to provide a fundamental knowledge on precoding please.
    Thank you.
    I have some works about precoding over MIMO channels. If you need tell me.

    Hello ahmad

    Please please please give me your work. I really need it. I sent you PM. please check. Thank you



  10. #10
    Junior Member level 3
    Points: 1,171, Level: 7

    Join Date
    Jul 2008
    Posts
    29
    Helped
    1 / 1
    Points
    1,171
    Level
    7

    what is common precoder

    Anymore information?



    •   AltAdvertisment

        
       

  11. #11
    Member level 4
    Points: 2,461, Level: 11
    silawi's Avatar
    Join Date
    Nov 2005
    Location
    Jordan
    Posts
    72
    Helped
    8 / 8
    Points
    2,461
    Level
    11

    what is pre-coding

    could u post a link for this book (precoding) please?



  12. #12
    Newbie level 3
    Points: 952, Level: 7

    Join Date
    Aug 2008
    Posts
    4
    Helped
    0 / 0
    Points
    952
    Level
    7

    what is pre coding

    could u post a link for this book (precoding) please?
    u can search it by google



  13. #13
    Newbie level 4
    Points: 708, Level: 5

    Join Date
    Mar 2009
    Posts
    7
    Helped
    0 / 0
    Points
    708
    Level
    5

    beamforming, precoding, difference

    Hi, I am a third year undergraduate student of electrical engineering. I have been assigned a summer project to to design,simulate and analyze a multi-antenna precoder for broadcasting data from a satellite to many ground terminals.
    I am supposed to do some background reading on this topic before joining the team. However, I have no knowledge of precoding as such...can you help me as to how should I go about reading on this subject? I mean right from scratch?



--[[ ]]--