# US 11,445,504 B2 · Method for distributing pilot frequency in massive antenna system

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- Number: US 11,445,504 B2
- Document ID: US11445504B2
- Status: Granted
- Kind: B2
- Application number: 16/960,074
- Filed: 2019-03-29
- Published: 2021-04-01
- Granted: 2022-09-13
- Earliest claimed: 2018-06-11
- Assignees: Sunwave Communications Co., Ltd.; Bti Wireless Limited; Bravo Tech Inc
- Applicants: Sunwave Communications Co., Ltd.
- Inventors: Fangmin Xu; Junrong Yan; Rulong Chu; Xingbao Ou
- Web page: https://patentgrep.com/patent/US11445504B2

## CPC

- H04W 72/0453: Resources in frequency domain, e.g. a carrier in FDMA
- H04L 5/0048: {Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091)}
- Y02D 30/70: in wireless communication networks
- H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- Y02D: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE

## Abstract

The disclosure discloses a method for distributing pilot frequency in a massive antenna system, including: dividing a pilot frequency set into three sub sets that are intersecting with each other, and then dividing the users of each cell into a cell central user and a cell edge user. The cell central users use an intersection set of three pilot frequency sub sets. The cell edge users of all cells use a difference set, an intersection set and a union set of three pilot frequency sub sets according to a certain rule. When it is designing to implement the pilot resource distribution plan of the massive antenna system, three cells that are adjacent with each other in the system are used as a cluster, and a pilot frequency use plan of any one cluster may be designed according to the method proposed by the disclosure, and then the same design plan is applied to other clusters in the system, and then is adjusted according to the user distribution of each cluster and the business distribution circumstance thereof.

## Claims

### Claim 1

A method for distributing pilot frequency in a massive antenna system, comprising the following steps:
pilot frequency set in the system are divided into three pilot frequency sets Φ1, Φ2 and Φ3, which are intersecting in pairs;
the pilot frequencies of all users in the system are planned by taking three cells as one cluster, Φ1, Φ2 and Φ3 are the pilot frequency sets that may be used by a cell 1, a cell 2 and a cell 3, wherein the cell 1, the cell 2 and the cell 3 are three cells that are adjacent with each other; a base station 1, a base station 2 and a base station 3 are the base stations of the cell 1, the cell 2 and the cell 3 respectively;
according to a distance between the users and the base stations, the users of every cell are divided into two types: cell central users and cell edge users;
the cell central users of all cells multiplex the completely same pilot frequency sets Φ1∩Φ2∩Φ3;
in terms of the cell edge users of the cell 1, the cell 2 and the cell 3, the pilot frequency distribution circumstances are as follows: (a) for the cell edge users in the cell 1, when the distance between a cell edge user and the base station 2 is smaller than a certain threshold value T1, a distributed pilot frequency set is: Φ1\Φ2; when the distance between the cell edge user and the base station 3 is smaller than T1, a distributed pilot frequency set is: Φ1\Φ3; when both the distances between the cell edge user and the adjacent two base stations are smaller than T1, the distributed pilot frequency set is: Φ1\(Φ2∪Φ3); (b) for the cell edge users in the cell 2, when the distance between the cell edge user and the base station 1 is smaller than a certain threshold value T2, the distributed pilot frequency set is: Φ2\Φ1; when the distance between the user and the base station 3 is smaller than T2, the distributed pilot frequency set is: Φ2\Φ3; when both the distances between the cell edge user and the adjacent two base stations are smaller than T2, a distributed pilot frequency set is: Φ2\(Φ1∪Φ3); and (c) for the cell edge users in the cell 3, when the distance between the user and the base station 1 is smaller than a certain threshold value T3, the distributed pilot frequency set is: Φ3\Φ1; when the distance between the cell edge user and the base station 2 is smaller than T3, the distributed pilot frequency set is: Φ3\Φ2; when both the distances between the cell edge user and the adjacent two base stations are smaller than T3, a distributed pilot frequency set is: Φ3\(Φ1∪Φ2).

### Claim 2 (depends on 1)

The method for distributing pilot frequency in a massive antenna system as claimed in claim 1, wherein the method for dividing the cell edge users is: measuring, by a user of every cell, intensity of a pilot frequency signal of a serving cell that is currently received, when the intensity of the pilot frequency signal is lower than a certain threshold value, the user is determined to be a cell edge user, or else the user are determined to be the cell central user.

### Claim 3 (depends on 1)

The method for distributing pilot frequency in a massive antenna system as claimed in claim 1, the threshold values T1, T2 and T3 are determined according to a practical demand of the system, the threshold values of all cells are the same.

### Claim 4 (depends on 1)

The method for distributing pilot frequency in a massive antenna system as claimed in claim 1, the threshold values T1, T2 and T3 are determined according to a practical demand of the system, the threshold values of all cells are different.

### Claim 5

A method for distributing pilot frequency in a massive antenna system, comprising the following steps:
pilot frequency sets in the system are divided into three pilot frequency sets Φ1, Φ2 and Φ3, which are intersecting in pairs;
the pilot frequencies of all users in the system are planned by taking three cells as one cluster, Φ1, Φ2 and Φ3 are the pilot frequency sets that are used by a cell 1, a cell 2 and a cell 3, wherein the cell 1, the cell 2 and the cell 3 are three cells that are adjacent with each other;
according to intensity of a pilot frequency signal between the users and the base stations, the users of every cell are divided into two types: a cell central user and a cell edge user, wherein, when the intensity of the pilot frequency signal is lower than a certain threshold value, the user is judged to be the cell edge user, or it is the cell central user;
wherein the cell central users of all cells multiplex an intersection of Φ1, Φ2 and Φ3; a target set is distributed to the cell edge users of all cells, the target set is determined according to at least one of a difference set, an intersection set and a union set, the difference set, the intersection set and the union set are determined according to at least two of three pilot frequency sub sets.