System and method for uplink inter cell interference coordination in a wireless access system

1. A method for scheduling time-frequency resources for a base station that supports multi-user multiple-input-multiple-output (MU-MIMO) uplink communication, the method comprising:

pairing a first cell edge user (CEU) and a first cell center user (CCU) to be served by the base station; and

assigning a first one of the time-frequency resources to both of the first CEU and the first CCU, thereby scheduling the first time-frequency resource for MU-MIMO transmission,

wherein the first time-frequency resource is associated with one or more normal power levels assigned for single user transmission, and

wherein the one or more normal power levels of the first time-frequency resource remain unadjusted after the assigning step.

2. The method of claim 1 , wherein the first time-frequency resource exists in a frequency band associated with CEU uplink transmission in the cell.

3. The method of claim 1 , wherein the one or more normal power levels of the first time-frequency resource are not adjusted as a result of the first time-frequency resource being scheduled for MU-MIMO transmission.

4. The method of claim 1 , wherein the one or more normal power levels comprise a first normal power level computed for single-user CEU transmissions and a second normal power level computed for single-user CCU transmissions, and wherein the first normal power level and the second normal power level remain unadjusted after the assigning step.

5. The method of claim 4 , wherein neither the first normal power level nor the second normal power level are adjusted as a result of the first time-frequency resource being scheduled for MU-MIMO transmission.

6. The method of claim 4 , wherein the first normal power level is projected to cause a threshold level of inter-cell-interference to be observed by one or more neighboring base stations when used to perform a single-CEU uplink transmission in the first time-frequency resource.

7. The method of claim 6 further comprising:

receiving a first uplink transmission and a second uplink transmission via the first time-frequency resource, wherein the first uplink transmission is transmitted by the first CEU at the first normal power level and the second uplink transmission is transmitted by the first CCU at the second normal power level, and

wherein an effective amount of inter-cell-interference observed by the one or more neighboring base stations does not substantially exceed the threshold level of inter-cell-interference that was projected to be caused by the single-CEU uplink transmission performed at the first normal power level.

8. The method of claim 7 , wherein the effective amount of inter-cell-interference observed by a neighboring base station is dominated by inter-cell-interference attributable to the first uplink transmission such that inter-cell-interference attributable to the second uplink transmission is masked by the inter-cell-interference attributable to the first uplink transmission.

9. An apparatus for scheduling time-frequency resources of a base station supporting multi-user multiple-input-multiple-output (MU-MIMO) uplink communication, the apparatus comprising:

a processor; and

a computer readable storage medium storing programming for execution by the processor, the programming including instructions to:

pair two users to be served by the base station;

schedule a MU-MIMO uplink transmission by allocating a common time-frequency resource to the two users, the common time-frequency resource being associated with a set of normal power levels for single-user uplink transmissions;

adjust the normal power settings when the common time-frequency resource is allocated to a pair of cell-edge-users (CEUs); and

maintain the normal power settings when the common time-frequency resource is allocated to a first CEU and a first cell-center-user (CCU).

10. The apparatus of claim 9 , wherein the first time-frequency resource corresponds with a frequency band designated for CEU uplink transmission.

11. The apparatus of claim 9 , wherein the normal power settings include a first normal power level for single-CEU transmissions, the first normal power level projected to produce a threshold level of inter-cell-interference in a neighboring cell when used to perform a single-CEU uplink transmission in the common time-frequency resource.

12. The apparatus of claim 11 , wherein the instructions to adjust the normal power settings when the common time-frequency resource is allocated to a pair of CEUs include instructions to:

communicate a reduced first power level to the pair of CEUs, thereby triggering the pair of CEUs to perform their respective uplink transmissions at the reduced power level.

13. The apparatus of claim 12 , wherein the reduced power level is equal to the first normal power level reduced by three decibels (3 dBs).

14. The apparatus of claim 12 , wherein the reduced power level is projected to produce a level of inter-cell-interference that does not substantially exceed the threshold level of inter-cell-interference (ICI) in the neighboring cell when used to perform multi-CEU uplink transmissions in the common time-frequency resource.

15. The apparatus of claim 11 , wherein the normal power settings further includes a second normal power level for single-CCU transmissions, and

wherein the instructions to maintain the normal power settings when the common time-frequency resource is allocated to the first CEU and the first CCU include instructions to

communicate the first normal power level to the first CEU, thereby triggering the first CEU to perform a first uplink transmission at the first normal power level in the first time-frequency resource; and

communicate the second normal power level to the first CCU, thereby triggering the first CCU to perform a first uplink transmission at the first normal power level in the first time-frequency resource.