# Why are the following two packet reception probabilities different?

In 3 page of this paper, the packet reception probability without interference is $$e^{-\theta N Ad^2/ P}$$. $$\theta$$ is sinr threshold. $$N$$ is a white noise. $$P$$ is power. $$d$$ is tx-rx distance and $$A$$ is path loss constant.

And I tried the following matlab simulation.

https://kr.mathworks.com/help/wlan/examples/802-11p-packet-error-rate-simulation-for-a-vehicular-channel.html

And by using the packet error rate table, I set packet reception probability (1 - packet error rate) according to tx-rx distance.

The friis path loss model is used, and the white noise is used in the snr calculation.

But packet reception probability in this simulation table, and above packet reception probability are different.

In the following graph, the probability of matlab simulation is much more than that of the paper analysis.

I don't know why.

• Can you say what exactly is the purpose of comparing these two? It seems like they are different models and you expect them to behave the same? – Engineer Dec 18 '19 at 14:24
• I want to know that the anlaysis model is suitable for the other simulation models. I think, excepting delay spread, the same rayleigh fading, path loss models were used. The mcs level is 2, and sinr threshold is 8 dB in the level. If there are any other communication obstacles in matlab simulation, the value of matlab will lower than the analysis model. But it is not. – jack han Dec 18 '19 at 15:58