The green communication for 5th generation Internet of Things base on the energy collecting and security issues is studied in this paper. The transceiver and power splitting factor are optimized aiming at minimizing the transmitting power at the source node subject to the security performance and energy collection. Since the optimization problem is a nonconvex function, an iteration optimization algorithm is proposed to divide the objective optimization function into two subproblems, namely, a

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... oint transmitter and PS factor optimization subproblem and a minimum mean-square error-based receiving filter optimization subproblem. Furthermore, since the transmitter and PS combining optimization subproblem is still a nonconvex function, the semidefinite relaxation technique is used to transform it into a convex function. The feasibility of the optimization problem and the convergency of the iteration algorithm are proved in theory, and the simulation results show the availability of the proposed scheme. The 5G IoT communication systems provide users with high data transmission, wide network coverage, multiple devices access, and low data delay, which bring more severe challenges to the secure transmission [3] . A large number of sensitive and confidential information, such as medical records, financial data, military information, and so on, is transmitted on wireless channels. Once the security of these sensitive information is destroyed, it will bring a huge threat to people's privacy, social economy, and even national security. How to ensure the secure transmission of information is an important prerequisite for future wireless network applications. As it was shown in information theory and cryptography, the secure transmission in wireless communications system can be guaranteed by applying the physical layer security (PLS) technologies instead of public key cryptography. In contrast to the traditional cryptographic systems, PLS technologies take advantage of the difference between the main channel capacity and the eavesdroppers channel capacity to ensure the security transmission of the data [4] [5] [6] . Cooperative communication and beamforming are common effective methods to improve secure performance. Cooperative diversity against channel fading can be provided by relaying. Beamforming is a signal pre-processing technique based on the antenna array. By designing the coefficients of the antenna array, an appropriate precoding matrix can be achieved to improve the receiving quality of the legal receiver [7] . Authors in [8] studied the PLS techniques in a multiuser IoT with untrusted relay. Three different scheduling schemes were proposed to reduce the complexity of scheduling algorithm. The secure relay communications in IoT with unknown number and locations eavesdroppers were investigated in [9] . Both single-antenna and multiple antennas scenarios were considered for improving the secrecy outage probability by designing the optimal power allocation and codeword rate. A secure transmission in IoT relay system with multiple eavesdroppers was considered in [10] . The authors assumed that the multiple eavesdroppers can cooperate to form joint receiving beamforming, a secure transmission scheme based on nonorthogonal multiple access is proposed. Mean-square error (MSE)-based transceiver optimization schemes have been studied a lot in different application scenarios to improve the performance of the systems [11] [12] [13] . The optimal design for transceiver in amplify-and-forward (AF) multiple-input multiple-output (MIMO) relay communication system was studied in [14] . The aim was to minimize the MSEs at the receivers subject to transmitting power constraints. An iterative transceiver design was proposed by exploiting the optimal structure of the transmitter, relay, and receiver matrices. Authors in [15] studied the transceiver design of a MIMO relay system based on the MSE. They studied the transceiver design in nonregenerative MIMO relay systems and developed an iterative scheme to jointly design the matrices of transceiver and relay node to minimize the maximal MSE of the signal estimation. Authors in [16] provided a minimum mean-square error (MMSE)based transceiver design with low calculating complexity for MIMO AF relaying system. The authors in [17] investigated the minimization of the total transmitting power of the base station and the relay station problem under both signal-to-interferenceplus-noise ratio and energy collecting constraints in a SWIPT multiuser multiple-input single-output relay system. They proposed an iterative algorithm based on alternating optimization and with guaranteed convergence to optimize the transceiver coefficients.