Interference mitigation in a wireless communication system
View Patent ↗The present invention provides a method of interference mitigation in a wireless communication system. The method that may include reducing transmission power associated with at least one first channel provided by at least one first base station associated with at least one corresponding first coverage area adjacent a second coverage area associated with a second base station concurrently with maintaining at least one transmission power associated with the second base station(s). The method may also include increasing the transmission power associated with the first channel(s) provided by the first base station(s) concurrently with reducing at least one transmission power associated with at least one first channel provided by the second base station(s).
1. A method of coordinating operation of a plurality of base stations, comprising:
transmitting, from a first base station during a first time interval, signals at a first transmission power concurrently with a second base station transmitting signals at a second transmission power, wherein the first and second base stations serve adjacent coverage areas over a first channel, and wherein the first transmission power is greater than the second transmission power; and
reducing transmission power of the first base station to the second transmission power during a second time interval subsequent to the first time interval and concurrently increasing transmission power of the second base station to the first transmission power, wherein the first and second time intervals and the corresponding transmission powers of the first and second base stations repeat according to a predetermined repeating pattern.
2. The method of claim 1 , wherein reducing the transmission power of the first base station comprises reducing the transmission power associated with a shared first channel provided by the first base station.
3. The method of claim 2 , wherein reducing the transmission power associated with the shared first channel provided by the first base station comprises reducing the transmission power associated with a shared high-speed downlink packet access channel provided by the first base station.
4. The method of claim 1 , wherein reducing the transmission power associated with the first base station comprises reducing the transmission power associated with the first channel concurrently with maintaining at least one transmission power associated with at least one second channel provided by the first base station.
5. The method of claim 4 , wherein maintaining said at least one transmission power of associated with said at least one second channel provided by the first base station comprises maintaining at least one transmission power of at least one of a dedicated channel and a common control channel provided by the first base station.
6. The method of claim 1 , wherein reducing the transmission power associated with the first channel provided by the second base station comprises reducing the transmission power associated with a shared first channel provided by the second base station.
7. The method of claim 6 , wherein reducing the transmission power associated with the shared first channel provided by the second base station comprises reducing the transmission power associated with a shared high-speed downlink packet access channel provided by the second base station.
8. The method of claim 1 , wherein reducing the transmission power associated with the first channel provided by the second base station comprises reducing the transmission power associated with the first channel concurrently with maintaining at least one transmission power associated with at least one second channel provided by the second base station.
9. The method of claim 8 , wherein maintaining said at least one transmission power associated with said at least one second channel provided by the second base station comprises maintaining at least one transmission power of at least one of a dedicated channel and a common control channel provided by the second base station.
10. The method of claim 1 , comprising scheduling at least one mobile unit to the first channel provided by the first base station based on channel quality feedback received from said at least one mobile unit.
11. The method of claim 10 , wherein scheduling said at least one mobile unit comprises determining a signal-to-interference ratio associated with said at least one mobile unit based on the channel quality feedback.
12. The method of claim 11 , wherein determining the signal-to-interference ratio comprises determining the signal-to-interference ratio based on the transmission power associated with the first channel provided by the first base station.
13. The method of claim 11 , wherein determining the signal-to-interference ratio comprises determining the signal-to-interference ratio based on channel quality indication feedback from a previous time interval.
14. The method of claim 11 , wherein determining the signal-to-interference ratio comprises determining the signal-to-interference ratio based on acknowledgement feedback associated with a present time interval or a previous time interval provided by a hybrid automatic repeat request (HARQ) process.
15. The method of claim 11 , wherein determining the signal-to-interference ratio comprises determining the signal-to-interference ratio based on an estimated Doppler frequency.
16. The method of claim 11 , wherein determining the signal-to-interference ratio comprises determining the signal-to-interference ratio based on feedback of an estimated interference level.
17. A method of coordinating operation of a plurality of base stations, comprising:
reducing, during at least one first time interval, transmission power associated with at least one first channel provided by at least one first base station associated with at least one corresponding first coverage area adjacent at least one second coverage area associated with at least one second base station concurrently with maintaining at least one transmission power associated with said at least one second base station; and
increasing, during at least one second time interval subsequent to said at least one first time interval, the transmission power associated with said at least one first channel provided by said at least one first base station concurrently with reducing at least one transmission power associated with at least one first channel provided by said at least one second base station, wherein said at least one first time interval and said at least one second time interval are predetermined according to a repeating pattern, wherein a beginning and an end of said at least one first and second time intervals are determined independently by said at least one first base station and said at least one second base station according to free running clocks in said at least one first base station and said at least one second base station, and wherein the free running clocks are not synchronized.
18. The method of claim 17 , wherein said at least one first base station preferentially schedules edge users during said at least one first time interval and said at least one second base station preferentially schedules edge users during said at least one second time interval.
19. The method of claim 18 , comprising determining the first and second time intervals to reduce an overlap interval during which said at least one first and second base stations are both scheduling edge users or to reduce a time interval during which neither said at least one first nor second base stations are scheduling edge users.
20. The method of claim 19 , wherein determining the first and second time intervals comprises determining the first and second time intervals based on a feedback delay associated with retransmission of at least one packet over said at least one first channel provided by the first base station.