Multi-user power control methods and procedures
Methods and systems for operation in a WLAN are provided. Methods and systems for a transmit power control (TPC) scheme are disclosed. In an embodiment, an access point (AP) may send a trigger frame to one or more stations (STAs) for synchronizing and scheduling uplink (UL) multi-user (MU) transmissions. The trigger frame may contain an open-loop power control index 1 and a power adjustment index 2. The one or more STAs may estimate pathloss using an indicated AP transmit power and received power to set a baseline transmit power. The one or more STAs may adjust their transmit power in the UL transmission period to be the indicated target receive power at the AP.
1. A method for use in a station (STA), the method comprising:
receiving a trigger frame that is broadcast to a plurality of STAs as a single transmission, the trigger frame comprising an indication that one or more resources in an upcoming uplink (UL) multi-user (MU) transmission opportunity are available to one or more STAs of the plurality of STAs for data transmissions, an indicated transmit power that an access point (AP) used to transmit the trigger frame, a first indicated target receive signal power at the AP associated with the STA, and at least a second indicated target receive signal power at the AP associated with a second STA of the plurality of STAs, wherein the first indicated target receive signal power and the second indicated target receive signal power are different;
measuring a received power of the trigger frame;
calculating a downlink pathloss of the trigger frame based on the indicated transmit power of the trigger frame and the measured received power of the trigger frame;
determining a STA transmit power based on the downlink pathloss and the first indicated target receive signal power at the AP; and
sending a data transmission in the one or more resources using the STA transmit power.
2. The method of claim 1 , further comprising:
adjusting the STA transmit power based on the target receive signal power at the AP.
3. The method of claim 1 , wherein the trigger frame further comprises a summation of transmit power and receiver sensitivity.
4. The method of claim 1 , wherein the trigger frame further comprises a targeted link margin at the AP, wherein the targeted link margin is defined as a difference between an expected received transmission power at the AP and an AP receiver sensitivity.
5. A station (STA) comprising:
an antenna; and
a processor operative coupled to the antenna;
the processor and the antenna configured to receive a trigger frame that is broadcast to a plurality of STAs as a single transmission, the trigger frame comprising an indication that one or more resources in an upcoming uplink (UL) multi-user (MU) transmission opportunity are available to one or more STAs in the plurality of STAs for data transmissions, an indicated transmit power that an access point (AP) used to transmit the trigger frame, a first indicated target receive signal power at the AP associated with the STA, and at least a second indicated target receive signal power at the AP associated with a second STA of the plurality of STAs, wherein the first indicated target receive signal power and the second indicated target receive signal power are different;
the processor and the antenna further configured to measure a received power of the trigger frame;
the processor configured to calculate a downlink pathloss of the trigger frame based on the indicated transmit power of the trigger frame and the measured received power of the trigger frame;
the processor further configured to determine a STA transmit power based on the downlink pathloss and the first indicated target receive signal power at the AP; and
the processor and the antenna further configured to send a data transmission in the one or more resources using the STA transmit power.
6. The STA of claim 5 , further comprising:
the processor and the antenna further configured to adjust the STA transmit power based on the target receive signal power at the AP.
7. The STA of claim 5 , wherein the information trigger frame further comprises a summation of transmit power and receiver sensitivity.
8. The STA of claim 5 , wherein the trigger frame further comprises a targeted link margin at the AP, wherein the targeted link margin is defined as a difference between an expected received transmission power at the AP and an AP receiver sensitivity.