ABSTRACT

We start with a direct transmission link as depicted in Figure 2.1(a) and assume the channel model incorporating path-loss and Rayleigh fading. The received signal at the destination d is modeled as

yd[n] = as,dxs[n] + nd[n], (2.1)

where xs[n] is the signal transmitted by a source s, n ∈ [1, ..., N ] is the index of the transmitting packet, and nd[n] is additive white Gaussian noise, with variance σ2n, at the receiver. The channel gain as,d between the nodes s and d is modeled as as,d = hs,d/dα/2s,d , where ds,d is the distance between the nodes s and d, α is the path-loss exponent, and hs,d captures the channel fading characteristics. The channel fading parameter hs,d is assumed to be complex Gaussian with zero mean and unit variance, and independent and identically distributed (i.i.d.) across times slots, packets, and links.