Pilot frequency scheduling method based on cross contamination in distributed MIMO system

Abstract

The invention discloses a pilot frequency scheduling method based on a cross contamination in distributed MIMO system. The method comprises the following steps: 1, computing the cross contamination index among user antennas according to large-scale fading, marking a user antenna set accomplishing the pilot frequency distribution as U, marking the antenna user set not accomplishing the pilot frequency distribution as a formula as shown in description, and marking the pilot frequency distribution condition as {sk}, wherein sk represents a pilot frequency sequence used by the k-th antenna; 2, selecting the antenna with the maximum cross contamination index among all user antennas from the formula as shown in description, and marking as k0, distributing an orthogonal pilot frequency sequence to the k0, updating the set {sk}, U and formula as shown in description until accomplishing the distribution of all orthogonal pilot frequency sequences; 3, continuously selecting the antenna with themaximum cross contamination index among all user antennas from the formula as shown in description, and marking as k0, computing the cross contamination index between the antennal sets using the samepilot frequency in the k0 and the U, multiplexing the pilot frequency sequence of the antenna set with the minimum cross contamination index, updating the set {sk}, U and formula as shown in description; and 4, checking whether the formula as shown in description is an empty set, representing that all antennas has accomplished the pilot frequency scheduling if the formula as shown in description is the empty set, or returning to step 3.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and relates to a pilot resource scheduling method in a wireless communication system, in particular to a pilot scheduling method based on a mutual pollution index in a distributed MIMO system. Background technique [0002] Distributed multiple input multiple output (Multiple Input Multiple Output, MIMO) system, as an antenna deployment method of massive MIMO system, is one of the key technologies to realize the fifth generation communication system (5G), which aims to achieve wider coverage of the system, More stable link and higher spectral efficiency and energy efficiency. As the name implies, the distributed MIMO system is to distribute the antennas of the original base station in the cell, that is, in the distributed MIMO system, the antenna units equipped with one or more antennas are scattered in the cell, and are received by optical fibers or dedicated radio frequency links....

AI Technical Summary

Problems solved by technology

Using the traversal algorithm to select the optimal scheme among all possible pilot allocation schemes can minimize the pilot pollution, but with the increase of the number of antennas, the complexity of the algorithm increases sharply, which does not have practical application value

Using the greedy algorithm, for each orthogonal pilot sequence, the antenna with better spatial dispersion is selected to reuse the pilot. The possibility of selecting an antenna with better spatial dispersion among the antennas will continue to decrease, that is, the user antenna allocated later will have a larger channel estimation error, and the performance is not ideal

Random allocation algorithm, that is, randomly select a certain number of user antennas to multiplex the same orthogonal pilot, its complexity is very low, but its performance is also extremely poor

Considering the complexity and performance comprehensively, there is an algorithm that tries to use different orthogonal pilot sequences for each antenna one by one, and selects the pilot with the smallest channel estimation error. The performance of this algorithm is better than the greedy algorithm and the random allocation algorithm. However, with The increase in the number of antennas, the computational complexity is still not very ideal

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