Inter-cell interference mitigation
AssigneeParallel Wireless, Inc.
InventorsPrashanth Rao, Yang Cao, Kaitki Agarwal
Life of this patent
Estimating the term…
Abstract
To address the problem of inter-cell interference in a heterogeneous network, several methods and systems are disclosed for determining interference caused by an aggressor mobile node, and transmitting at appropriate times and with transmit power that does not cause interference. Methods disclosed include using X2 communications, such as HII and RNTP messages, switching to an alternative radio access technology, sniffing at the eNodeB to obtain information, coordinating with a cloud coordination server, and using CFI information to avoid interfering with communications on the PDCCH.
Claims11
A method for reducing downlink interference at a first base station, the first base station being a micro cell, comprising:
- obtaining, at a cloud coordination server from the first base station, neighboring radio power information for a second base station via a measurement report message from a mobile device attached to the first base station, the second base station being a macro cell;
- sending a message from the cloud coordination server to assign, at the first base station, a transmit power for the mobile device based on the neighboring radio power information;
- obtaining, at the cloud coordination server from the first base station, a format indicator of a neighboring control channel used by the second base station;
- sending a second message from the cloud coordination to assign the first base station, at least one control channel parameter, the control channel parameter comprising a control channel symbol location, a control channel modulation code scheme, or a control channel aggregation level, for a user channel at the mobile device and based on the neighboring control channel format indicator;
- sending the assigned transmit power and assigning the at least one control channel parameter to the mobile device;
- assigning the control channel symbol location for the downlink channel to avoid symbol locations indicated as being in use in the neighboring control channel;
- and
- sniffing a Control Format Indicator (CFI) of the macro cell to avoid interfering with a Physical Control Format Indicator Channel (PCFICH).
A method for reducing downlink interference at a second base station, comprising:
- obtaining, at a cloud coordination server from a first base station, radio power information of the second base station received from a mobile device via a measurement report message;
- sending a message from the cloud coordination server to assign, at the first base station, a transmit power for a mobile device based on the radio power information of the second base station;
- obtaining, at the cloud coordination server from the first base station, a format indicator of a neighboring control channel used by the second base station;
- sending a second message from the cloud coordination server as a base station control plane signaling message to assign, at the first base station, at least one control channel parameter, the control channel parameter comprising a control channel symbol location, a control channel modulation code scheme, or a control channel aggregation level, for a user data channel at the mobile device and based on the neighboring control channel format indicator;
- assigning the control channel symbol location for the downlink channel to avoid symbol locations indicated as being in use in the neighboring control channel;
- sniffing a Control Format Indicator (CFI) of the macro cell to avoid interfering with a Physical Control Format Indicator Channel (PCFICH);
- and
- reducing the transmit power for the mobile device at the first base station, wherein the first base station is a micro cell and the second base station is a macro cell.
Dependencies are inferred from the claim text.