Method for coordinating inter-cell interference in heterogeneous network and heterogeneous network

Patent metadata

Field	Value
Publication number	US-9307423-B2
Application number	US-201214131370-A
Country	US
Kind code	B2
Filing date	Jul 9, 2012
Priority date	Jul 13, 2011
Publication date	Apr 5, 2016
Grant date	Apr 5, 2016

Abstract

Provided are a method for coordinating inter-cell interference in a heterogeneous network (HetNet) and the heterogeneous network. The method includes: forming M normal base stations and low-power nodes within coverage of the respective normal base stations in the heterogeneous network into a coordinated group; combining mute/non-mute states of bandwidths of the M normal base stations to obtain a plurality of states of the coordinated group; a user of each of the normal base stations feeding at least one first CQI back to the normal base station; a user of each of the low-power nodes feeding one or more second CQIs back to the low-power node; using the first CQI and the second CQIs as a basis to make capacity estimation of the coordinated group; and setting the mute/non-mute states of the bandwidths of the M normal base stations in accordance with a state of the coordinated group corresponding to an optimal system capacity so as to perform data transmission. In the method for coordinating interference provided by the present invention, M transmission points each including one or more normal base stations and low-power nodes covered by the respective normal base stations can be formed into a coordinated group, thereby extending processing for the normal base stations up to all the transmission points in the coordinated group.

First claim

The invention claimed is:

1. A method for coordinating inter-cell interference in a heterogeneous network (HetNet), comprising:
a step A of forming M macro base stations (M is greater than 1) and low-power nodes within coverage of the respective macro base stations in the heterogeneous network into a coordinated group;
a step B of combining mute/non-mute states of bandwidths of the M macro base stations to obtain a plurality of states of the coordinated group;
a step C of a user equipment of each of the macro base stations in the coordinated group, feeding at least one first channel quality indicator (CQI) corresponding to the states of the coordinated group back to the macro base station;
a step D of a user equipment of each of the low-power nodes covered by the macro base stations in the coordinated group, feeding one or more second CQIs corresponding to the states of the coordinated group back to the low-power node;
a step E of using the at least one first CQI and the one or more second CQIs as a basis to make capacity estimation of the coordinated group and obtaining a plurality of system capacities corresponding to the respective states of the coordinated group; and
a step F of setting the mute/non-mute states of the bandwidths of the M macro base stations in accordance with a state of the coordinated group corresponding to an optimal system capacity so as to perform data transmission, wherein
the plurality of states of the coordinated group in the step B include a state where the M macro base stations are all non-mute and a state where the M macro base stations are all mute.

2. The method of claim 1 , wherein
in the step C, the user equipment of the macro base station feeds back the first CQI of the state where the M macro base stations are all non-mute,
in the step D, the user equipment of the low-power node feeds back two second CQIs of the state where the M macro base stations are all non-mute and the state where the M macro base stations are all mute, and
the first CQI and the second CQIs are all related to interference strength outside the coordinated group.

3. The method of claim 1 , wherein
the states of the coordinated group in the step B include any combinations of the mute/non-mute states of the M macro base stations,
in the step C, the user equipment of each of the macro base stations decides M first CQIs, the first CQIs being related to signal strength of j-th (j=1, 2, . . . , M) macro base stations and interference strength outside the coordinated group, and
in the step D, the user equipment of each of the low-power nodes decides M+1 second CQIs, the second CQIs being related to signal strength of the low-power node, signal strength of the respective macro base stations in the coordinated group and the interference strength outside the coordinated group.

4. The method of claim 3 , wherein the step E comprises:
each of the macro base stations in the coordinated group updating the M first CQIs fed back from the user equipment of each of the macro base stations to be CQIs in one-to-one correspondence with the mute/non-mute sates of any combinations of the mute/non-mute states of other macro base stations in the coordinated group;
each of the low-power nodes updating the M+1 second CQIs fed back from the user equipment of each of the low-power nodes to be CQIs in one-to-one correspondence with the states of the coordinated group; and
estimating the system capacities of the coordinated group in the respective states based on the updated CQIs.

5. The method of claim 1 , wherein
the states of the coordinated group in the step B are determined by a number of mute macro base stations and the number of mute macro base stations corresponding to an i-th state of the coordinated group is i (i=0, 1, . . . , M),
in the step C, the user equipment of each of the macro base stations decides M first CQIs and an i-th first CQI (i=0, 1, . . . , M−1) is related to signal strength of the macro base station to which the user equipment belongs, signal strength of another non-mute macro base station in the i-th state of the coordinated group and interference strength outside the coordinated group;
in the step D, the user equipment of each of the low-power nodes decides M+1 second CQIs and an i-th second CQI (i=0, 1, . . . , M) is related to signal strength of the low-power node, the signal strength of the non-mute macro base station in the i-th state of the coordinated group, and the interference strength outside the coordinated group.

6. The method of claim 5 , wherein
the i-th first CQI is a minimal CQI in the i-th state of the coordinated group measured by the user equipment of the macro base station, and
the i-th second CQI is a minimal CQI in the i-th state of the coordinated group measured by the user equipment of the low-power node.

7. The method of claim 1 , wherein
each of the states of the coordinated group in the step B corresponds to one of selections by, once a number N close of mute macro base stations is decided, selecting N close macro base stations arbitrarily from the M macro base stations and making the N close macro base stations mute, a value of N close being any of 1, . . . , M−1,
in the step C, the user equipment of each of the macro base stations decides M first CQIs, each of the first CQIs being related to signal strength of the macro base station to which the user equipment belongs, signal strength of another non-mute macro base station in the corresponding state of the coordinated group, and interference strength outside the coordinated group, and
in the step D, the user equipment of each of the low-power nodes decides M+1 second CQIs, the second CQIs being related to signal strength of the low-power node, signal strength of non-mute macro base stations in the corresponding state of the coordinated group, the interference strength outside the coordinated group.

8. The method of claim 3 , wherein
the step C further comprises the user equipment of each of the macro base stations feeding the determined M first CQIs back to the macro base station, and the step D further comprises the user equipment of each of the low-power nodes feeding the determined M+1 second CQIs back to the low-power node, or
the step C further comprises the user equipment of each of the macro base stations grouping and comparing the determined M first CQIs, selecting a minimal first CQI from each group and feeding the first CQI back to the macro base station, and the step D further comprises the user equipment of each of the low-power nodes grouping and comparing the determined M+1 second CQIs, selecting a minimal second CQI from each group and feeding the second CQI back to the low-power node.

9. The method of claim 2 , wherein the interference strength outside the coordinated group is actual interference strength measured with actual mute/non-mute states of macro base stations outside the coordinated group by a corresponding user equipment, or estimated interference strength measured by the corresponding user equipment assuming the macro base stations outside the coordinated group are all non-mute.

10. The method of claim 1 , wherein
the step C further comprises the user equipment of each of the macro base stations assuming a plurality of states of the coordinated group shiftable from a state of the coordinated group at a last transmission time as the states of the coordinated group at a current feedback time and feeding first CQIs corresponding to the states of the coordinated group at the current feedback time back to the macro base station, and
the step D further comprises the user equipment of each of the low-power nodes assuming a plurality of states of the coordinated group shiftable fro

Assignees

• Nagata Satoshi
• Wang Jing
• Jiang Yu
• She Xiaoming
• Chen Lan
• Suda Hirohito
• Ntt Docomo Inc

Inventors

• Nagata Satoshi
• Wang Jing
• Jiang Yu
• She Xiaoming
• Chen Lan
• Suda Hirohito

Classifications

• H04W72/27

  between access points · CPC title

• H04W72/541

  using the level of interference · CPC title

• H04W72/082

  Electricity · mapped topic

• H04W72/0426

  Electricity · mapped topic

• H04W24/02 Primary

  Arrangements for optimising operational condition · CPC title