SatSig topic:

number of slots for remotes

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Dec 27^th, 2008 at 8:00pm

Hi

How can I determine the number of slots available for the remotes to transmit based on the factors like Bandwidth, Modulation, Symbol rate, FEC, Frame length etc .

Could you please explain me with a formula/calculation for this to get an approximate !!

Thanks in advance

smlt

Dec 28^th, 2008 at 1:20pm

Use the iNPT tool to make the calculations. It can be found on the TAC website.

Dec 28^th, 2008 at 1:45pm

Also, read the iNPT handbook with an explanation of the terminology.
See here: iDirect network planning tool (680k pdf file)
I suggest you print it out for study.

Best regards, Eric.

Dec 28^th, 2008 at 5:09pm

Thanks for the info . I have that tool already . but instaed if you have any other calculation to determine , pls let me know . atleast to get an approximate . i am bit confused with this tool somewhere .

Dec 28^th, 2008 at 8:08pm

For an approximation, examine the case study in the iNPT handbook.

350 remote sites need an 11.4 Mbit/s outlink. Note this gives 32kbit/s per site. Each PC needs a minimum of 10kbit/s so there are no more than an average of 3.2 PCs per site.

8 return links each at 690 kbit/s with 38 remotes per return link
3 return links each at 1.2 Mbit/s with 17 remotes per return link

Note that if you have sites with different traffic needs (and thus different tariffs) you can group them separately (as above for the two types of return links).

Total 21.3 MHz on the satellite for 350 remote sites. Note 21.3 x $6000 / 350 = $365 per month per site.

You can input your ideas of traffic needed by each remote and work out your own conclusions.

Do the calculation at the end to work out the satellite cost of providing the service per remote site. The price will vary over a wide range depending how much traffic capacity you assign and your actual satellite cost. $6000 per month per MHz is my example.

It is most important is that you don't raise user expectations above what they are paying you to provide.

Best regards, Eric.