Secure degrees of freedom for general MIMO interference channel under rank-deficiency

As a more trackable performance metric for secrecy capacity,the secure degrees of freedom(SDoF)are widely studied for most multiuser networks in the high signal to noise ratio(SNR)region.However,the SDoF for these networks under rank-deficiency and arbitrary antenna configurations have not yet been determined.In this paper,the SDoF of two-user general multiple-input multiple-output(MIMO)interference channel with confidential messages(ICCM)under rank-deficiency are derived.For the two-user rank-deficient MIMO ICCM,the model is generalized to fully asymmetric settings,where the transmitters and receivers are equipped with arbitrary antennas.The outer bound of SDoF is the union of three outer bounds that are based on the Fano’s inequality and the secrecy constraints,the secrecy penalty lemma and the role of a helper lemma,and the transmitters cooperation,respectively.The SDoF region is subdivided into five regions according to the number of transceivers antennas,and each region has an achievability scheme with designed null space transmission and alignment techniques.Numerical results indicate that the SDoF increase at first and then decrease as the rank of the channel matrix decreases.The SDoF improve by increasing the transmitting antenna or reducing receiving antenna,but the effect of the transmitting antenna is greater.

Lattice-Basis Reduction Precoding Based on Successive Interference Cancellation Design for Multiuser MIMO Downlink System

Two kinds of lattice-basis reduction precoding schemes based on successive interference cancellation are proposed.The successive interference cancellation(SIC) structure can be obtained by either orthogonal and a right triangular matrix(QR) decomposition,or the Vertical Bell Labs Layered Space Time(VBLAST) algorithm which provides optimal user ordering.Moreover,the extended channel approach is applied to the proposed SIC-based schemes.Simulation results show that the proposed schemes can achieve comparable BER performance to vector precoding(VP).