SYSTEMS AND METHODS FOR SMALL CELL UPLINK INTERFERENCE MITIGATION

• US 20170223594A1
• Filed: 04/11/2017
• Published: 08/03/2017
• Est. Priority Date: 09/30/2011
• Status: Active Grant

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: COMSTOCK, David
• Granted Patent: US 11,452,018 B2
• Time in Patent Office: Days
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 16/32 Hierarchical cell structures
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/20 for optimising the interference level
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 36/326 by proximity to another entity
• CPC Class Codes: H04W 88/02 Terminal devices
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 92/20 between access points

Abstract

Systems and methods for facilitating the mitigation of interference in the uplink of a small cell caused by macrocell user equipment in the case where the macrocell cannot identify the interfering macrocell user equipment because the user equipment cannot detect and report the small cell'"'"'s downlink due to the small cell'"'"'s uplink/downlink coverage imbalance. In an embodiment, the small cell provides the macrocell with a notification of the interference, the configuration information about its Physical Random Access Channel (PRACH), and a plurality of unique preambles and transmission times for non-contention-based transmissions on the small cell'"'"'s PRACH. The macrocell orders each of one or a plurality of macrocell user equipment to transmit one of the unique preambles on the small cell'"'"'s PRACH. The small cell reports to the macrocell the detected preamble transmissions, which allows the macrocell to identify interfering user equipment and perform corrective actions.

Claims

1. A method comprising:

transmitting, from a first base station to a user terminal, first information, the first information indicating a timing advance to be used, by a user terminal, for adjusting a timing to transmit an uplink signal to a second base station;

receiving, at the user terminal, the first information from the first base station; and

transmitting, from the user terminal to the second base station, the uplink signal by using the information.

2. The method according to claim 1, further comprising:

performing a handover of the user terminal from the first base station to the second base station.

3. The method according to claim 1, wherein the first base station transmits information, as the first information, indicating a timing advance used between the first base station and the user terminal.

4. The method according to claim 1, wherein the first information indicates that the timing advance is zero.

5. The method according to claim 1, further comprising:

receiving, at the first base station, second information from the second base station, the second information indicating radio resources used by the second base station; and

transmitting, from the first base station to the user terminal, the second information; and

wherein the user terminal transmits the uplink signal to the second base station by using the first information and the second information.

6. A user terminal comprising:

a processor; and

a transceiver configured to receive first information from a first base station, the first information indicating a timing advance used, by the user terminal, for adjusting a timing to transmit an uplink signal to a second base station, wherein the transceiver is further configured to transmit the uplink signal to the second base station by using the first information.

7. A base station comprising:

a processor; and

a transceiver configured to transmit first information to a user terminal, the first information indicating a timing advance used, by the user terminal, for adjusting a timing to transmit an uplink signal to a second base station.

8. A method for determining a timing advance not based on a preamble transmitted from a user terminal, the method comprising:

determining that the timing advance is zero, wherein the timing advance is information for determining a timing to transmit an uplink signal from the user terminal to the base station.

9. The method according to claim 8, wherein the determining is performed in case that the user terminal is closer to the first base station than the second base station.

10. A method for determining a first timing advance not based on a preamble transmitted from a user terminal, the method comprising:

determining the first timing advance to be same as a second timing advance determined by a second base station;

wherein the first timing advance is information for determining, by the user terminal, timing to transmit an uplink signal to the first base station, and the second timing advance is information for determining, by the user terminal, timing to transmit an uplink signal to the second base station.

11. The method according to claim 10, wherein the determining is performed in case that a distance between the user terminal and the first base station is same as a distance between the user terminal and the second base station.