Intercell interference mitigation
Methods and apparatus are described for mitigating intercell interference in wireless communication systems utilizing substantially the same operating frequency band across multiple neighboring coverage areas. The operating frequency band may be shared across multiple neighboring or otherwise adjacent cells, such as in a frequency reuse one configuration. The wireless communication system can synchronize one or more resource allocation regions or zones across the multiple base stations, and can coordinate a permutation type within each resource allocation zone. The base stations can coordinate a pilot configuration in each of a plurality of coordinated resource allocation regions. Subscriber stations can be assigned resources in a coordinated resource allocation region based on interference levels. A subscriber station can determine a channel estimate for each of multiple base stations in the coordinated resource allocation region to mitigate interference.
1. A method of receiving, at a subscriber station, downlink (DL) data in a wireless communication system, the method comprising:
transmitting, by the subscriber station to a base station, channel quality information, wherein the channel quality information comprises information indicative of received signal strength of a transmission received from the base station at the subscriber station, and wherein the channel quality information is indicative of a need of reduced interference levels at the subscriber station;
receiving, at the subscriber station from the base station in response to the channel quality information being indicative of the need of reduced interference levels at the subscriber station, an allocation of a first frequency and time resource for a coordinated time period, wherein the first frequency and time resource is included in downlink frequency and time resources comprised in a coordinated DL transmission zone and wherein the first frequency and time resource is available and useable by the base station for the coordinated time period; and
receiving, at the subscriber station from the base station, data according to the first frequency and time resource during the coordinated time period, wherein the subscriber station performs, in response to the first frequency and time resource being included in downlink frequency and time resources comprised in the coordinated DL transmission zone, interference mitigation of at least one signal from at least one other base station to improve the quality of the received data.
2. The method of claim 1 , wherein the downlink frequency and time resources include a portion of a downlink frequency band.
3. The method of claim 1 , wherein the channel quality information is a channel quality indicator (CQI).
4. The method of claim 1 , wherein the channel quality information includes at least one of: signal to interference ratio (SIR), interference to noise ratio (INR), carrier to interference ratio (CIR), or carrier to interference and noise ratio (CINR), frame error rate (FER), symbol error rate (SER), a packet error rate (PER), a bit error rate (BER).
5. The method of claim 1 , wherein the downlink frequency and time resources include a plurality of Orthogonal Frequency Multiple Access (OFDM) resources.
6. The method of claim 5 , wherein each of the plurality of OFDM resources is associated with a plurality of subcarriers.
7. The method of claim 1 , further comprising:
receiving, at the subscriber station from the base station on a condition that the subscriber station supports a more robust modulation coding scheme, an updated modulation coding scheme, wherein the data is received according to the updated modulation coding scheme.
8. The method of claim 1 , wherein the first frequency and time resource includes open subchannels within the coordinated DL zone.
9. A subscriber station comprising:
a transceiver; and
a processor, wherein
the transceiver and the processor are configured to:
transmit, to a base station, channel quality information, wherein the channel quality information comprises information indicative of received signal strength of a transmission received from the base station at the subscriber station, and wherein the channel quality information is indicative of a need of reduced interference levels at the subscriber station;
receive, from the base station in response to the channel quality information being indicative of the need of reduced interference levels at the subscriber station, an allocation of a first frequency and time resource for a coordinated time period, wherein the first frequency and time resource is included in downlink frequency and time resources comprised in a coordinated DL transmission zone and wherein the first frequency and time resource is available and useable by the base station for the coordinated time period; and
receive, from the base station, data according to the first frequency and time resource during the coordinated time period, wherein the subscriber station performs, in response to the first frequency and time resource being included in downlink frequency and time resources comprised in the coordinated DL transmission zone, interference mitigation of at least one signal from at least one other base station to improve the quality of the received data.
10. The subscriber station of claim 9 , wherein the downlink frequency and time resources include a portion of a downlink frequency band.
11. The subscriber station of claim 9 , wherein the channel quality information is a channel quality indicator (CQI).
12. The subscriber station of claim 9 , wherein the channel quality information includes at least one of: signal to interference ratio (SIR), interference to noise ratio (INR), carrier to interference ratio (CIR), or carrier to interference and noise ratio (CINR), frame error rate (FER), symbol error rate (SER), a packet error rate (PER), a bit error rate (BER).
13. The subscriber station of claim 9 , wherein the downlink frequency and time resources include a plurality of Orthogonal Frequency Multiple Access (OFDM) resources.
14. The subscriber station of claim 13 , wherein each of the plurality of OFDM resources is associated with a plurality of subcarriers.
15. The subscriber station of claim 9 , wherein the transceiver and the processor are further configured to:
receive, from the base station on a condition that the subscriber station supports a more robust modulation coding scheme, an updated modulation coding scheme, wherein the data is received according to the updated modulation coding scheme.
16. The subscriber station of claim 9 , wherein the first frequency and time resource includes open subchannels within the coordinated DL zone.