Method and apparatus for controlling cell reselection

Patent metadata

Field	Value
Publication number	US-9253690-B2
Application number	US-201314103825-A
Country	US
Kind code	B2
Filing date	Dec 11, 2013
Priority date	Feb 24, 2012
Publication date	Feb 2, 2016
Grant date	Feb 2, 2016

Abstract

Embodiments of the present application provide a method and an apparatus for controlling cell reselection, which relate to the field of communication terminal technologies. The method includes: when the signal strength of a current serving cell of a terminal is lower than a set value and the duration of which exceeds a first time period, acquiring signal strengths of the current serving cell and a neighboring cell within a second time period; determining signal stability of the current serving cell according to the signal strength of the current serving cell, and determining signal stability of the neighboring cell according to a signal strength of the neighboring cell; and keep the current serving cell when the signal stability of the neighboring cell is not better than the signal stability of the current serving cell. The embodiments of the present application are mainly applied to a cell reselection process.

First claim

What is claimed is:

1. A method for controlling cell reselection in a cellular communication network, comprising:
monitoring, by a communication device, signal strength of a current serving cell;
when the signal strength of the current serving cell has been lower than a threshold value for longer than a first time period, successively acquiring, by the communication device, signal strengths of the current serving cell and at least one neighboring cell within a second time period for a predetermined number of times;
determining, by the communication device, signal stability of the current serving cell according to the signal strength of the current serving cell, and signal stability of the neighboring cell according to the signal strength of the neighboring cell; and
when the signal stability of the neighboring cell is better than the signal stability of the current serving cell, reselecting, by the communication device, the neighboring cell as a serving cell;
wherein the signal stability is represented by a signal stability value, the signal strength is represented by a signal strength value, and the signal stability value is a variance value of the signal strength value, and wherein the signal stability of the current serving cell is represented by the signal stability value of the current serving cell, and the signal stability value of the current serving cell is calculated according to:

Q
var
′

=

∑

n
=
1

N

⁢

⁢



q
n

-

Q
avg



N

wherein Q′ var is the signal stability value of the current serving cell, q n is a signal strength value of the current serving cell that is acquired at the n th time point within the second time period, Q avg is an average value of the signal strength values of the current serving cell that are acquired at N time points within the second time period, N is the number of times when the signal strength of the current serving cell is acquired within the second time period, and N is greater than or equal to 2.

2. The method according to claim 1 , wherein the signal stability of the neighboring cell is represented by the signal stability value of the neighboring cell, and the signal stability value of the neighboring cell is calculated according to:

Q
r

=

∑

n
=
1

N

⁢

⁢



w
n

-

Q
a



N

wherein Q r is the signal stability value of the neighboring cell, w n is a signal strength value of the neighboring cell that is acquired at the n th time point within the second time period, Q a is an average value of the signal strength values of the neighboring cell that are acquired at N time points within the second time period, and N is the number of times when the signal strength of the neighboring cell is acquired within the second time period, and N is greater than or equal to 2.

3. The method according to claim 1 , wherein if the signal stability of the neighboring cell is not better than the signal stability of the current serving cell, the communication device remains to be served by the current serving cell.

4. The method according to claim 3 , wherein after the communication device reselects the neighboring cell as the serving cell or after the communication device remains to be served by the current serving cell, the method further comprises:
successively acquiring, by the communication device, signal strengths of the current serving cell for a predetermined number of times in a third time period;
calculating signal stability of the current serving cell according to the signal strengths obtained in the third time period;
if the signal stability of the current serving cell is not better than a preset threshold, acquiring signal strengths of the current serving cell and the neighboring cell within a fourth time period; or
if the signal stability of the current serving cell is better than the preset threshold, acquiring, at a next time point, a signal strength of the current serving cell and calculating the signal stability of the current serving cell according to signal strengths obtained at the predetermined number of times and the next time point, except the signal strength obtained at the first time point.

5. The method according to claim 4 , wherein after acquiring the signal strengths of the current serving cell and the neighboring cell within the fourth time period when the signal stability of the current serving cell is not better than the preset threshold, the method further comprises:
determining signal stability of the current serving cell according to the signal strength of the current serving cell, and determining signal stability of the neighboring cell according to the signal strength of the neighboring cell; and
staying on the current serving cell when the signal stability of the neighboring cell is not better than the signal stability of the current serving cell, or reselecting the serving cell to be the neighboring cell when the signal stability of the neighboring cell is better than the signal stability of the current serving cell.

6. The method according to claim 4 , wherein there are two or more neighboring cells of which the signal strengths are acquired and the signal stabilities are determined by the communication device, wherein after acquiring the signal strengths of the current serving cell and the two or more neighboring cells within the fourth time period when the signal stability of the current serving cell is not better than the preset threshold, the method further comprises:
determining signal stability of the current serving cell according to the signal strength of the current serving cell, and determining signal stabilities of the neighboring cells according to signal strengths of the neighboring cells; and
staying on the current serving cell when the best signal stability among signal stabilities of the neighboring cells is not better than the signal stability of the current serving cell; or reselecting the serving cell to be a neighboring cell corresponding to the best stability when at least one signal stability among

Assignees

• Huawei Device Co Ltd
• Huawei Device Co Ltd

Inventors

• Wan Jiang
• Wei Konggang

Classifications

• H04W48/20

  Selecting an access point · CPC title

• H04W36/0061 Primary

  of neighbour cell information · CPC title

• H04W36/0083

  Determination of parameters used for hand-off, e.g. generation or modification of neighbour cell lists · CPC title

• H04W36/0085

  Hand-off measurements · CPC title