Coherent times and preamble rates of different wireless standards

Hi,

I want to get actual values of the channel coherence time and preamble
percentage used in practical wireless standards (e.g. GSM, WCDMA, LTE...).

1). I have referred the GSM and LTE standards (some ETSI documentations).
But I couldn't find a definition or a value for channel coherence time.
There are frame times and slot times.

Can someone please advice to find the practical channel coherence times for
these standards?

2). I also need to find the preamble percentage (how often do the preambles
are transmitted) for different systems. In Standards, preamble / training
structure is presented but rate is not presented. 

I appreciate if someone can advice regarding how to find these values and
provide suitable references. 

Thanks,
Regards,
Dan.	 

_____________________________		
Posted through www.DSPRelated.com

On 9/1/2013 9:42 PM, Dan25 wrote:
> Hi,
>
> I want to get actual values of the channel coherence time and preamble
> percentage used in practical wireless standards (e.g. GSM, WCDMA, LTE...).

Coherence time: 1/4 wavelength divided by typical speed of a vehicle.
This is ~ milliseconds.

What is preamble persentage?

Vladimir Vassilevsky
DSP and Mixed Signal Designs
www.abvolt.com

On Sun, 01 Sep 2013 21:42:43 -0500, "Dan25" <98432@dsprelated> wrote:

>Hi,
>
>I want to get actual values of the channel coherence time and preamble
>percentage used in practical wireless standards (e.g. GSM, WCDMA, LTE...).
>
>1). I have referred the GSM and LTE standards (some ETSI documentations).
>But I couldn't find a definition or a value for channel coherence time.
>There are frame times and slot times.
>
>Can someone please advice to find the practical channel coherence times for
>these standards?

Channel coherence time is channel dependent, and varies widely
depending on the environmental assumptions.  The standards themselves
don't usually include this information, but many standards also have
associated documents describing the channel models used for
verification, and those documents will usually state or give enough
information to determine the channel coherence times for the various
models used.   

Note that for the standards you've mentioned there are multiple
channel models for different situations, e.g., urban, suburban, rural,
and often with varying degrees of mobility.   The coherence time will
vary across the different models as the mobility, terrain and other
environmental assumptions change.

>2). I also need to find the preamble percentage (how often do the preambles
>are transmitted) for different systems. In Standards, preamble / training
>structure is presented but rate is not presented. 

You can probably sort that out from the standards, but it will require
studying the various packet lengths and how the preambles are applied
to each.

>I appreciate if someone can advice regarding how to find these values and
>provide suitable references. 
>
>Thanks,
>Regards,
>Dan.	 
>
>_____________________________		
>Posted through www.DSPRelated.com

Eric Jacobsen
Anchor Hill Communications
http://www.anchorhill.com