Pilot frequency dynamic allocation method of multi-cell large-scale MIMO system

Abstract

The invention provides a pilot frequency dynamic allocation method of a multi-cell large-scale MIMO system. In the TDD multi-cell large-scale MIMO system, users in a cell are divided into a cell margin user group and a cell non-margin user group by a base station according to a received user signal to noise ratio difference. As for cell margin users, a seamless pilot frequency dynamic allocation method is adopted, neighbor cells are divided into a plurality of cell groups, mutually orthogonal pilot frequency sequences are allocated to margin users of neighbor cells in the cell groups, and pilot frequency is reused by margin users of neighbor cells out of the cell groups; as for cell non-margin users, a combination optimal low-complexity pilot frequency allocation method is adopted, and the pilot frequency is reused by margin users between neighbor cells according to a maximization pilot frequency allocation utility function. The pilot frequency allocation flexibility and equality of the system are enhanced, the marginal network performance of the cells is improved, the pilot frequency pollution of the whole large-scale MIMO system is reduced, and the use ratio of the system is improved.

Description

Technical field [0001] The invention belongs to the technical field of mobile communication, and relates to a method for dynamic pilot allocation of a multi-cell massive MIMO system. Background technique [0002] Compared with traditional MIMO technology, massive MIMO technology has the advantages of serving more users on the same time-frequency resources, effectively suppressing inter-cell interference, higher data rates, and lower power consumption, which can make the system capacity and energy efficiency gain Greatly improved, the spectrum utilization rate reached an unprecedented level. Therefore, massive MIMO technology has received widespread attention from the academic community and is one of the core technologies of the 5th generation (5G) mobile communication system. [0003] In a TDD (Time-Division Duplex) multi-cell massive MIMO system, the existing pilot allocation method is to allocate orthogonal pilot sequences within a cell, and reuse the same pilot sequence between...

AI Technical Summary

Problems solved by technology

The inter-cell pilot multiplexing uses the same multiplexing criterion for all users, without fully considering the differences between cell edge users and cell non-edge users, because the user signal power received by the base station is not only related to the user's transmission Power is related to the relative position of the user and the base station. Usually, the signal-to-noise ratio received by the base station from the cell edge user is low, and the interference to the adjacent cell is relatively large. With the existing pilot allocation method, it is difficult for cell edge users to allocate pilot sequences with better orthogonality, so they will suffer from very serious pilot pollution

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