1

I am wondering if the theoretical maximum transmission range under Omnet++ (veins framework) is the same as the maximum interference distance.

I want to confirm some calculations done before by another person, Last one concludes that the transmission range is equal to :

  • 127m for Txpower = -80dbm & sensitivity = 10mW
  • 300m for Txpower = -80dbm & sensitivity = 15.5mW
  • 1000m for Txpower = -94dbm & sensitivity = 20mW

For all calculations: path loss coeffcient alpha = 2 & frequency = 5890Mhz

On my side, I get respectively 127m, 159m and 907m. I am not able to know why to much difference. I use the free space path loss formula.

Can someone confirm to me these result ?

vhu
  • 12,244
  • 11
  • 38
  • 48
HanniBaL90
  • 535
  • 6
  • 18

1 Answers1

7

You are correct: if a frame's receive power in Veins 3 is under the sensitivity threshold, the packet can never be decoded (independent of its received SINR).

The free space path loss formula used in Veins 3 is:

For a transmit power of 20 mW and a sensitivity threshold of -94 dBm (I am assuming that this is just a typo in your question), the distance where the received power drops under the sensitivity threshold can be calculated to be (roughly) 907 meters.

Since you specifically asked for the maximum interference range, though, please note that the transmit power can be selected for each frame and the sensitivity threshold can be configured for each radio. They are therefore not used for calculating the maximum interference range (the distance where a sender is deemed so far away that it will not even contribute interference). This distance is calculated independently by the global ConnectionManager module, whose job it is to deliver "ongoing radio transmission" events to all affected modules. It uses a completely separate (global) set of parameters to calculate this range.

Community
  • 1
  • 1
Christoph Sommer
  • 6,893
  • 1
  • 17
  • 35
  • Just another point to add, currently i am using Veins 2.0-rc1, i know that is old but i cannot move to another one for now. Anyway i guess that is the same. I check the config.xml file, i have noted that two models are used: The free space path loss + The two ray ground interference. This later model is complexe, but is it possible that it distorts ennough the results to get these differences ? – HanniBaL90 Jul 31 '15 at 21:45
  • 1
    The "Free Space" and the "Two Ray Interference" model both compute the attenuation of a signal for a given distance. For 800m to 1000m their output is similar, for other distances it is not. You can see a plot comparing their output on the [Veins website](http://veins.car2x.org/documentation/modules/#tworay). Note that you should not use both path loss models at the same time (just like you should not use the apply the same path loss model twice). – Christoph Sommer Aug 04 '15 at 07:54
  • Ok, thanks for the reply, but i'am using an already writed config.xml file, this last one contains 2 Analogue models : "TwoRayInterferenceModel" & "SimpleObstacleShadowing". So should i have a config.xml file like this ? How can i compute the theoric max transmission distance ? – HanniBaL90 Aug 04 '15 at 11:17
  • 1
    It seems like this is a separate issue. Let's not add a discussion on this topic (calculating maximum transmission range for Two Ray Interference) as an answer to another question (is maximum transmission range the same as maximum interference range in Veins). – Christoph Sommer Aug 04 '15 at 15:01