The radio range of Wireless devices is generally in meters. If the scenario which you have created has a grid that spans in Kilometers and if the distance between the wireless nodes is too much (beyond the radio range) it would not be possible for any communication to happen.
The wireless medium characteristics are modeled under channel characteristics using parameters such as path loss, fading, and shadowing. If there is no path loss then it would mean there is no restriction (infinite range) in terms of radio range of the devices. However, if path loss is set then the distance between the source and destination should be within the radio range. Else one would notice zero throughputs for the applications.
Note:
The factors which affect the range are:
a. Transmitter power (More Tx power implies higher range)
b. Path loss (Higher path loss exponent leads to a lower range)
c. Receiver sensitivity (Lower Rx sensitivity leads to a higher range. Rx sensitivity is in negative dB, hence lower means more negative).
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