P k S denotes the transmit power of source SU allocated to the k th relaying link.
The transmit power of source and relay are represented by ( P_{mathcal {S}} ) and ( P_{mathcal {R}} ), respectively.
For simplicity, we assume the AWGN has unit variance and the transmit power of source and relays is the same.
Following [29], the optimal transmit power at source is given by begin{array}{*{20}l} P_{s}^{star} &=frac{1}{2, alpha}left -beta + sqrt{betalpha}left -beta, kappa} right), end{array} (43).
It is confirmed that by employing dual antennas at relay for energy harvesting is beneficial, and the throughput gain is significant when transmit power at source and the received power at relay are carefully calculated.
Cooperative communication plays a promising role to expand the coverage of wireless networks, save uplink transmit power of source due to highly constrained wireless resources [1 3], and increase the spatial diversity without increasing the number of antennas [4].
Next, we formulate the optimization problem to minimize expected value of WMSE m under a limited available transmit power at source nodes as presented in Problem 1: min F 1, F 2, G E E { WMSE m } subject to Tr ( F 1 F 1 H ) + Tr ( F 2 F 2 H ) ≤ P T (19).
Fig. 7 The instantaneous transmission rate versus different values of transmit power of source node with L S =L R =3. Figure 8 considers time allocation in the case of energy harvesting and information processing under non-CCI and CCI cases.
where h i,i ∈ {1,2} denotes the complex channel gain with zero mean and unit variance between S i and R; ω i = 2 π f d i T, T is the symbol interval and f d i is the Doppler shift introduced between S i and R. nr(k) stands for a zero mean complex Gaussian random variable with variance σ n 2, and P i denotes the transmit power at source S i.
P T denotes the transmit power of sources and relays.
