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branch metric of MLSE equalizer for GSM

Started by richard_zhang July 14, 2008
Hi All,

I am reading an article about GSM MLSE equalizer. The article link is
here.

http://www.freescale.com/files/dsp/doc/app_note/AN2943.pdf?fpsp=1&WT_TYPE=Application%20Notes&WT_VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation

This article is quite brief, and I have two questions here

1) is the Equation 6 in the article correct?
2) How can I get Equation 6 from Equation 5? Can anybody give some idea or
good detailed reference?

Thank you.


Richard
>Hi All, > >I am reading an article about GSM MLSE equalizer. The article link is >here. > >http://www.freescale.com/files/dsp/doc/app_note/AN2943.pdf?fpsp=1&WT_TYPE=Application%20Notes&WT_VENDOR=FREESCALE&WT_FILE_FORMAT=pdf&WT_ASSET=Documentation > >This article is quite brief, and I have two questions here > >1) is the Equation 6 in the article correct? >2) How can I get Equation 6 from Equation 5? Can anybody give some idea
or
>good detailed reference? > >Thank you. > > >Richard >
%%%% Hi To understand MLSE equaliser properly, try to read Digital Communications by John G Proakis, 4th edition. Read section 10.1.2 to 10.1.3, i.e. from page 601 to 607. he has also given one example. chintan
On Jul 14, 3:34 am, "richard_zhang" <hardhear...@yahoo.com.cn> wrote:
> Hi All, > > I am reading an article about GSM MLSE equalizer. The article link is > here. > > http://www.freescale.com/files/dsp/doc/app_note/AN2943.pdf?fpsp=1&WT_... > > This article is quite brief, and I have two questions here > > 1) is the Equation 6 in the article correct? > 2) How can I get Equation 6 from Equation 5? Can anybody give some idea or > good detailed reference? > > Thank you. > > Richard
Richard, I haven't analysed it completely but what you'll want to do to prove the result is to express the equation in vector form So, the metric to be maximized can be written as the norm of an L- sized vector: M^\tilde[k] = || x - A*h ||^2 where x and h are L*1 vectors and A is an L*L matrix containing the symbols to be decoded. Then, use vector algebra to simplify, some of the terms will get removed because each element of A has magnitude=1 and you should get the form in equation 6. Thanks, Dilip.