Change transmission range of IEEE 802.15.4 in HC(S)08 microcontroller

[magic]

Hi all...

I'm using Freescale/Zigbee 802.15.4 on HC(S)08 microcontroller. I would like to know how to change the transmission range. Does anyone knows the command or any documents that could assist me with this? Is there a way to set the transmission range to an exact value or close to it? For eg. 1 metre?

[Shankman · Accepted solution]

Hi im not sure if this helps but you, as im only a uni student

But to my understanding transmission range is effected by power,dB of fade margin, sensitivity and frequency etc.

Path Loss = 20* log(4*π*r/λ) dB (Eq. 1), where
r = distance between transmitter and receiver
λ = wavelength

Path Loss = P(t) + G(t) + G(r) - R(s) - F(s) dB (Eq. 2), where
P(t) = transmitted power
G(t) = gain of transmit antenna
G(r) = gain of receive antenna
R(s) = sensitivity of receiver
F(s) = fading margin, (experimentally determined to be 22dBm)

Equating these two equations can give you a rough estimate of transmission range in "ideal" conditions

or more simply do the maths with this

P R = [P T G T G R ? 2 ] / [F S (4pr) 2 ]

P R = received power
P T = transmitted power
G T = gain of transmit antenna
G R = gain of receive antenna
F S = losses due to multipath, obstacles, etc.
? = wavelength
p = pi
r = distance between transmitter and receiver

But you can reduce transmission power of HS(s)08 in my case i use the MC9S08GT60 an in the "accelerometer demo" the code to reduce transmission power is in there first "c file" but its a bit of stuffing around through the header files to see the guts of the function.

Regards

Kris

PS i attached the source code