1. 10018H -TGh Proposal for Transmitter Power Control (TPC)
Month 2000
doc.: IEEE /001
January 2001
10018H -TGh Proposal for Transmitter Power Control (TPC)
Christopher J. Hansen, Matthew Fischer, Rajugopal Gubbi, Joonsuk Kim
Broadcom Corporation
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation
C. Hansen, Broadcom Corporation

2. Outline Background 802.11a PHY Modifications 802.11 MAC Modifications
Month 2000
doc.: IEEE /001
January 2001
Outline
Background
802.11a PHY Modifications
MAC Modifications
TPC Operation
Summary
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation
C. Hansen, Broadcom Corporation

3. January 2001
Background
TPC is a requirement for operation on the 5 GHz band in Europe
TPC will also improve network performance by reducing interference.
Small additions to the a PHY and MAC standards will allow interoperable networks to meet both goals.
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

4. January 2001
Background
We define only the PHY and MAC changes necessary to implement TPC algorithms that will meet the ERC requirements.
Actual algorithms are implementation dependent.
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

5. 802.11a PHY Modifications Will changes to the PHY help TPC? Yes!
January 2001
802.11a PHY Modifications
Will changes to the PHY help TPC? Yes!
Standardize power settings for TPC
minimize interference and maintain interoperability
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

6. 802.11a PHY Modifications Absolute TX Power Settings for all STAs
January 2001
802.11a PHY Modifications
Absolute TX Power Settings for all STAs
-15 dBm to +30 dBm, 3 dB steps
16 settings; 4 bit representation
Closely follows ETSI Hiperlan/2 AP_Tx_Level
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

7. January 2001
MAC Modifications
TPC information is exchanged with Probe request and Probe response frames
Probe Request frame format
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

8. 802.11 MAC Modifications Corresponding Probe response frame
January 2001
MAC Modifications
Corresponding Probe response frame
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

9. January 2001
MAC Modifications
Probe response fixed fields repeat previously received values from AP/PC
Copy fields from last received beacon
We define new element for TPC
TPC power setting request/response
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

10. 802.11 MAC Modifications TPC power setting request element
January 2001
MAC Modifications
TPC power setting request element
Command flag bit: 0 for tell me your power level; 1 for set your power to the level setting
TX power level setting (see PHY Section)
Element ID
Length
Flag
TX Power Level
Octets: 1
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

11. 802.11 MAC Modifications TPC power setting response element
January 2001
MAC Modifications
TPC power setting response element
TX power setting
Element ID
Length
TX Power Level
Octets: 1
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

12. January 2001
MAC Modifications
Global TPC status information is conveyed in the Beacon Frame
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

13. 802.11 MAC Modifications Global TPC Status element defines:
January 2001
MAC Modifications
Global TPC Status element defines:
Maximum TX power in the BSS
Element ID
Length
Max TX Power Setting
Octets: 1 1 1
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

14. January 2001
TPC Operation
Power levels can be controlled in both a centralized and a distributed fashion
AP can use global TX power limit within BSS
STAs can request power level changes from other STAs
AP (and STAs) can individually set power level for each destination STA
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

15. January 2001
TPC Operation
Standardized power settings allow consistency of operation in a network with different STA implementations
AP can guarantee ERC Requirements are met
TPC can be made fair
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation

16. Summary We propose that TGh consist of the following:
January 2001
Summary
We propose that TGh consist of the following:
802.11a TX power level standardization
MAC Probe request/response elements for TPC
Each STA being able to send probe request/response frames to another STA in the BSS
Hansen, Fischer, Gubbi, and Kim, Broadcom Corporation