Should SINR formula include Pr, Noise and Interference in dB or linear

Hi all,

In a system with a,b,c,d,e as the communication nodes with 'a' being a receiver and 'b' being the transmitter. Then Pr(b->a) is the intended signal (unit mWatt). I have calculated interference in mWatt as: I(mWatt) = Pr(c->a) + Pr(d->a) + Pr(e->a)

If noise is -174dBm

In the formula SINR = Pr(b->a)/(I + N), I and N should be in Linear (mWatt) scale or log-scale (dBm)