With [q.sub.2] = 0 the TWAF relay network reduces to a conventional one-way relay network and no information can be acquired at [N.sub.1], this conflicts with the bidirectional transmission nature of two-way relay networks.
Since TWAF relay network carries two data streams of opposite directions concurrently, the system is in outage if either [N.sub.1] or [N.sub.2] is in outage.
Proposition 3: When two source nodes have non-identical traffic requirements, the overall OP of a TWAF relay network with VG policy can be lower bounded by
(18, 22, 33)) which deals with TWAF relay network with VG policy under homogenous Rayleigh/Rayleigh fading channels, of course in our analysis the Rician channel introduces a new definition for [[omega].sub.1].
Lemma 1: the OPA that minimize the asymptotic overall OP (15) of TWAF relay network with VG policy operating over mixed Rician and Rayleigh fading channels, under the total power constraint of [q.sub.1] + [q.sub.2] + [q.sub.3] = 1, [q.sub.i] > 0, i = 1, 2, 3, is given by
Lemma 2: The OESP that minimize the asymptotic system overall OP (15) of TWAF relay network with VG policy operating over mixed Rician and Rayleigh fading channels, where two source nodes are loaded with equal transmission power, is given by
4 we plot the overall OP performance of different PA schemes in TWAF relay network with FG and VG policies when source nodes have non-identical traffic requirements.
In this section, we study the channel capacity of TWAF relay networks, with FG and VG policies, respectively.
The lower bounds and high SNR approximations for the channel capacity of the end-to-end links in TWAF relay network operating over mixed Rician and Rayleigh fading channels, with both FG and VG polices, are given in Table 4 with [F.sub.1](x) = ln(1 + [e.sup.x])/2ln2, [F.sub.2](x) = x/2ln2, [c.sub.1] = 1 + [rho][q.sub.1][[OMEGA].sub.1] + [rho][q.sub.2][[OMEGA].sub.2], [??] = [rho][q.sub.1][[OMEGA].sub.1] + [rho][q.sub.2][[OMEGA].sub.2].
7, we plot the system sum capacity of TWAF relay network against SNR and relay location, respectively.