认知中继网络中基于虚拟MIMO的鲁棒波束赋形设计

his paper jointly employs cogntive radio and cooperative communication to improve the system spectrum efficiency and reduce the energy consumption. Specially, virtual MIMO-based robust beamformer design problem is investigated in the cognitive relay network (CRN) with the consideration of imperfect channel information state at transmitter (CSIT), where multiple relay nodes make up a virtual antenna array to forwad the signal transmission of multiple seconday users. The problem is formulated with the aim of minimzing the total consumped power while guaranteeing the maximal transmit power constraint for each relay node, the minimal received signal to interference plus noise ratio (SINR) constraint for each secondary user and the maximal received interference constraint for each primary user. To solve the problem, the closed-form expressions for the worst-case received SINR of secondary users and the worst-case received interference of primary users are derived by taking advantage of the Lagrangian dual method. Thereafter, the semi-definite relaxation (SDR) method is presented to solve the beamformer design problem efficiently. Simulation results show that compared with the existing schemes which no not consider the CSIT error, the proposed scheme can guarantee the minimal received SINR of secodary users and the maixmal receieved interference of primary users well, achieving efficient and legitimate spectrum sharing in CRNs.