Optimal Transmission Schemes for DF Relaying Networks Using SWIPT

Energy Efficiency Maximization for SWIPT Enabled Two-Way DF Relaying

“…That is, if both functions f 1 (P i , x i ) = log 2 1 + |hi| 2 (Pi−xi) W σ 2 and f 2 (t, x A , x B ) = tlog 2 1 + Kī t a j x A |h A | 2 + a k x B |h B | 2 + K 1 , (i,ī = A or B), are concave, then P 5 is convex. Taking the secondorder derivative of f 1 (P i , x i ), the Hessian matrix is given by As for f 2 (t, x A , x B ), the Hessian matrix is given by (6) at the top of this page, where cī A = Kīa j |h A | 2 , cī B = Kīa k |h B | 2 and cī 1 = KīK 1 ,ī ∈ {A, B}. Since the second and third order leading principle minors are 0, ∂ 2 f2(t,xA,xB) ∂(t,xA,xB) 2 is negative semidefinite and f 2 (t, x A , x B ) is concave.…”

“…Inspired by this, SWIPT enabled wireless relaying was proposed and devoted to solving this problem [6], [7]. For the SWIPT enabled one-way relay network, the authors in [6] proposed an optimal transmission scheme of joint time allocation and PS to maximize the system capacity under the decode-and-forward (DF) protocol. In [7], the authors studied the optimal PS/TS ratio for the one-way amplify-and-forward (AF) relay network with a non-linear EH model.…”

On the Outage Performance of SWIPT-Based Three-Step Two-Way DF Relay Networks

“…Let x i be the decoded signal for x i . If both x A and x B are successfully decoded during the first two slots, then at the third time slot (1−2β)T the relay R broadcasts the normalized signal x R = θ A x A + θ B x B to both terminal nodes using the 2 The assumption will not cause any loss of generality to our analysis. This is because the average signal-to-noise-ratios (SNRs) of all channels are essential for the analysis of system outage performance, and the average SNRs depend on the transmit power at terminals and all the fading channels.…”

“…Since it is difficult to find the closed-form expression for P i 1 due to the integral s2 s1 exp(z 1 x + z2 x )dx for any value of z 1 and z 2 = 0, we employ Gaussian-Chebyshev quadrature [2], [14] to obtain an approximation for P i 1 , as follows 5) where N is a parameter that determines the tradeoff between complexity and accuracy for the Gaussian-Chebyshev quadrature based approximation; ν n = cos 2n−1 2N π, and χ (01) n = Ωi 2 ν n + Ωi 2 . Note that an acceptable accuracy can be achieved for a small value of N , which is verified in our simulations.…”

“…S IMULTANEOUS wireless information and power transfer (SWIPT) has been recognized as a promising technology to alleviate the energy constraint in relay networks while maintaining reliable communications through a power-splitting (PS) or time-switching (TS) scheme [1], [2]. In a bidirectional transmission network, two-way relaying operates in two steps or three steps instead of four steps as required in one-way relaying, thus achieving a higher capacity [3].…”