- This topic has 6 replies, 1 voice, and was last updated 13 years, 2 months ago by pix.
10th March 2010 at 20:28 #61391Fresh OptGuest
I want to calculate percentage of coverage in the whole country. Which threshold in dBm should I take for calculation? -95 dBm? -105 dBm? Anyone did the same?
I appreciate if someone can give me an answer.
Fresh Opt11th March 2010 at 07:04 #61392PixGuest
It depends mostly if you want to provide indoor, incar or outdoot coverage.
for outdoor coverage, a threshold of -85dBm is the minimum (safer to take -80dBm)
indoor, you use -70dBm or more.
pix14th March 2010 at 18:55 #61393Fresh OptGuest
Thank you Pix.
My manager wants to know how many percents is covered our country, territorially and for population area. I can do that from RNP but I didn’t know which threshold to take. I have seen some operators, they used threshold -106 dBm. What you think about that.
Fresh Opt.15th March 2010 at 12:55 #61394PixGuest
Ok, i gave you “design” values 🙂 To have a rough idea of your operator coverage, you can use any value you want… even though -106dBm seems to low. A MS shall be sensitive down to -102dBm. Not less than this.
So the minimal threshold you can use is -102dBm. But if anyone goes out and check the validity of your study, you’ll be in trouble 🙂 Also, in your RNP, did you set your tool to take into account body margin, fast fading and lognormal margin ?
For me, a “safe” threshold (for your purpose) would be -92dBm, for outdoor coverage.
A little aggressive would be -95dBm. And if noone is never going to check it, or if you want to compare your network with another operator that is using a certain threshold, then -of course- use their threshold !
If they already use -106dBm, then use -106dBm. Otherwise your network will look bad.15th March 2010 at 15:44 #61395Fresh OptGuest
Thanks Pix for valuable informations.
Regards,15th March 2010 at 15:57 #61396paraHOGuest
The thresholds used do vary from country to country. One operator in the UK uses BTS 1 (-105dBm) as the back-stop for the lowest received signal strength at the BTS receiver.
For the MS receiver see TBR:
20.6 RX Measurement
20.6.1 Signal Strength
1) To verify that the RMS received signal level at the receiver input is reported by the MS to the BTS over the full range of -110dBm to -48 dBm with a relative accuracy of +/- 1dB within any 20dB portion of the total measurement range.
2) To verify that the RMS received signal level at the receiver input is reported by the MS to the BTS over the full range of -110dBm to -48 dBm with an absolute accuracy of +/- 4dB from -110 dBm to -70dBm under normal conditions and +/- 6dB over the full range under both normal and extreme conditions.
3) To verify that if the received signal level falls below the reference sensitivity level for the class of MS and if the MS reports this signal then the MS shall report a level between the
reference sensitivity level and the actual received level.15th March 2010 at 17:53 #61397pixGuest
but measurements are not the same as “being able to make a call”… MS are supposed to be able to make a call at -102dBm (minimum performance defined by 3GPP).
however, due to fading, body margin, interference… this value is very difficult to achieve. That’s why a 10dB security margin is the least any radio planner would take to cover his … “arse” 🙂 (that’s how they say in UK, right ?)
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