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abuantenna
Joined: 14 Nov 2005
Posts: 185
Helped: 1
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 21 Mar 2006 1:57 link budget 5.8ghz |
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Hi,
Is there any good site give good summary of designing indoor wireless communication link for 2.45 adn 5.8 GHz bands?
I've read many things about Eb/No and noise figure. I can calculate required power transmitter if some variables are availbale.
I'd like to connect between many ideas. There is one link give something called alpha= bit rate* noise figure*(Eb/No)/(Pr/No)
I couldn't understand this equation!!!
Also, in many IEEE standards, there is nothing about antennas gain. There is something about power sensitivity. Is this the minimum received power ??
Also, how much Eb/No for QPSK? and how they calculated already ??
Regards
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21 Mar 2006 1:57 Ads |
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vfone
Joined: 10 Oct 2001
Posts: 2327
Helped: 326
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21 Mar 2006 16:13 link calculation+wlan |
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I think that is a mistake in your equation:
…..(Eb/No)/(Pr/No) is equal with Eb/Pr….that means No is disappeared
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abuantenna
Joined: 14 Nov 2005
Posts: 185
Helped: 1
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22 Mar 2006 10:55 wlan link budget calculation |
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Hello,
In factm it is not my equation. It is from one presentation from Berkeley university!!
I agree with you. There is something I can't understand.
Regards
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vfone
Joined: 10 Oct 2001
Posts: 2327
Helped: 326
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22 Mar 2006 11:21 Re: Link budget calculations for WLAN ?? |
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| The guys from Berkeley are humans also…two hands, two legs and one brain…they can make mistakes as anyone else.
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abuantenna
Joined: 14 Nov 2005
Posts: 185
Helped: 1
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22 Mar 2006 11:39 Re: Link budget calculations for WLAN ?? |
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Hello,
Yes, you are absolutely right. I agree. But, still the problem where is the correct equation? What is the real equation for parameter alpha, which means loss factor, as I understand?
Regards
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vfone
Joined: 10 Oct 2001
Posts: 2327
Helped: 326
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22 Mar 2006 17:22 Re: Link budget calculations for WLAN ?? |
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WLAN link budget is dictated by the radiated throughput and range where SNR will fall off, increasing the Packet Error Rate.
Sensitivity in the 802.11 standard is defined as the minimum input level of the received signal at which the certain Packet Error Rate occurs.
For WLAN is no antenna specifications as we have in cellular radios. Sometimes you can find some recommendations for antenna gain and pattern, to maintain the range.
Here you can find sensitivity values and some relations between BER/PER and Eb/No:
http://www.analogzone.com/hft_0505.pdf
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abuantenna
Joined: 14 Nov 2005
Posts: 185
Helped: 1
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22 Mar 2006 21:59 Re: Link budget calculations for WLAN ?? |
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Hi,
I fully understand you. In fact, I did calculations for requirments for 2.4 GHz and 5.8 GHz bands.
I used standard specifications as in http://www.comsoc.org/livepubs/ci1/DLPREVIEW/hirt.pdf
I discovered that we don't need an antenna (or antenna with 0dBm will be enough) for the case of 5.75 GHz band!!!
That was a real surprise for me. So, I decided to search more about the matter.
Regards
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vfone
Joined: 10 Oct 2001
Posts: 2327
Helped: 326
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22 Mar 2006 23:47 Re: Link budget calculations for WLAN ?? |
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| There is no type of wireless mobile network that requires more than 0dBd (-2.14dBi) antenna gain, on the mobile side. So, your calculation is ok.
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abuantenna
Joined: 14 Nov 2005
Posts: 185
Helped: 1
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23 Mar 2006 0:06 Re: Link budget calculations for WLAN ?? |
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Hi,
Oh, that's great. Is it standard for mobile netowrks? I mean: is it kind of policy for any WLAN ??
Regards
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