Energy-efficient interference alignment method for multi-cell MIMO (multiple-input and multiple-output) system

Abstract

The invention discloses an energy-efficient interference alignment method for a multi-cell MIMO (multiple-input and multiple-output) system and belongs to the technical field of wireless communications. The method includes: firstly, interferences on a receiving end from other cells are aligned to a same space and thoroughly eliminated by a central interference alignment algorithm, and analytical solutions to a transmitting and receiving beamforming matrix are obtained; secondly, one group is selected from the analytical solutions obtained at the previous step according to energy efficient norm, and the transmitting and receiving beamforming matrix with optimal system energy efficiency is obtained under the given requirements for various user data rates; thirdly, the optimal transmitting and receiving beamforming matrix is substituted into an energy efficient expression, and optimal power matching is obtained by binary search with the goal of maximum system energy efficiency while the requirements of users for data rates are met. The method has the advantages that implementation is easier while the performance is better than that of frequency division multiplexing and that of the power matching method using minimal total transmitting power as the goal, and the method is widely applicable.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and particularly relates to an interference alignment method with priority on energy efficiency in a multi-cell multi-antenna (MIMO) system. Background technique [0002] In a multi-cell MIMO system, inter-cell interference is a major factor that inhibits the improvement of system throughput. When each base station shares channel information and data information, inter-cell interference can be converted into useful signals; when only channel information is shared between base stations, cooperative beamforming is an effective method to suppress interference and improve spectral efficiency. [0003] If there are more than three cooperating base stations and each user is equipped with multiple antennas, the interference from other different cells can be aligned in the same space at the receiving end, thereby improving the multiplexing gain of the system. Existing interference alignme...

AI Technical Summary

Problems solved by technology

However, transmission strategies with high spectral efficiency may not necessarily bring high energy efficiency

[0005] Although the existing energy-efficient beamforming can improve the energy efficiency of the system in single-user scenarios and single-cell multi-user scenarios, in the scenario of multi-cell MIMO systems, the energy efficiency goal in the energy efficiency optimization model cannot be achieved due to the existence of inter-cell interference. Both function and data rate constraints are non-convex, making it difficult to optimize using traditional methods

Even if the existing interference alignment algorithm is used, although inter-cell interference can be completely eliminated, the energy efficiency objective function and data rate constraints in the optimization model can be transformed into quasi-concave and convex respectively, but the power allocation is not optimal (in the sense of energy efficiency), so such an approach still results in a loss of power

[0006] The existing interference alignment algorithm improves the multiplexing gain of the multi-cell MIMO system to achieve high spectral efficiency, but its energy efficiency is not necessarily optimal

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