Energy Efficient Robust Beamforming and Cooperative Jamming Design for IRS-Assisted MISO Networks

Energy Efficient Robust Beamforming and Cooperative Jamming Design for IRS-Assisted MISO Networks

Energy-efficient design and secure communications are of crucial importance in wireless communication networks. However, the energy efficiency achieved by using physical layer security can be limited by the channel conditions. In order to tackle this problem, an intelligent reflecting surface (IRS) assisted multiple input single output (MISO) network with independent cooperative jamming is studied. The energy efficiency is maximized by jointly designing the transmit and jamming beamforming and IRS phase-shift matrix under both the perfect channel state information (CSI) and the imperfect CSI. In order to tackle the challenging non-convex fractional problems, an algorithm based on semidefinite programming (SDP) relaxation is proposed for solving energy efficiency maximization problem under the perfect CSI case while an alternate optimization algorithm based on S-procedure is used for solving the problem under the imperfect CSI case. Simulation results demonstrate that the proposed design outperforms the benchmark schemes in term of energy efficiency. Moreover, the tradeoff between energy efficiency and the secrecy rate is found in the IRS-assisted MISO network. Furthermore, it is shown that IRS can help improve energy efficiency even with the uncertainty of the CSI.

节能设计和安全通信在无线通信网络中至关重要。然而，利用物理层安全所实现的能效会受到信道条件的限制。为了解决这一问题，研究了一种具有独立协作干扰的智能反射面（IRS）辅助多输入单输出（MISO）网络。通过在完美信道状态信息（CSI）和不完美CSI两种情况下联合设计发射和干扰波束成形以及IRS相移矩阵，使能效最大化。为了解决具有挑战性的非凸分式问题，针对完美CSI情况下的能效最大化问题提出了一种基于半定规划（SDP）松弛的算法，而针对不完美CSI情况下的问题则使用了一种基于S - 过程的交替优化算法。仿真结果表明，所提出的设计在能效方面优于基准方案。此外，在IRS辅助的MISO网络中发现了能效和保密率之间的权衡。进一步表明，即使存在CSI的不确定性，IRS也有助于提高能效。