1. Representation of Transmitter Characteristics
Month Year
doc.: IEEE yy/xxxxr0
December 2011
Representation of Transmitter Characteristics
Date:
Authors:
Steve Shellhammer, Qualcomm Inc.
John Doe, Some Company

2. Month Year
doc.: IEEE yy/xxxxr0
December 2011
Abstract
In some regulatory domains it may be required to transmit to the database some of the transmitter characteristics of the AP and STAs. These transmitter characteristics may include the spectral mask and the maximum antenna gain. This presentation proposes a information element (IE) that can be used to transmit these transmitter characteristics from the STAs to the AP, so that the AP can provide them to the database
Submission addresses the following CIDs: 1183 and 1184
Steve Shellhammer, Qualcomm Inc.
John Doe, Some Company

3. December 2011
Motivation
Some regulatory domains (e.g. Ofcom) will provide different channel availability and maximum transmit power depending on the STA TX characteristics
TX characteristics include spectral mask and maximum antenna gain
Both the antenna gain and the spectral mask may be carrier frequency dependent
IEEE af is including a representation of the TX characteristics
Our goal is to design an accurate and compact representation
Steve Shellhammer, Qualcomm Inc.

4. Proposal – Information Element
December 2011
Proposal – Information Element …
Element ID
Length
Control
TX Characteristics 1
TX Characteristics 2
TX Characteristics N IE
Octets 1 1 1
Control Field
Meaning
Current TX Characteristics Format
1-255
Reserved
The IE contains multiple fields (“TX Characteristics n”)
Each field covers a set of channels, to support carrier frequency dependency in the TX characteristics
Steve Shellhammer, Qualcomm Inc.

5. Proposal –TX Characteristics Field
December 2011
Proposal –TX Characteristics Field
The TX Characteristics Field consists of a number of fields
Len
Start
Stop
AGain
Spectral Mask
Octets 1 2 2 2 4N
Field
Meaning
Format
Len
Length of TX Characteristics Field
Unsigned 8-bit Integer
Start
Start WLAN Channel Number
Unsigned 16-bit Integer
Stop
Stop WLAN Channel Number
AGain
Maximum antenna gain (with 0.01 dB resolution) in dBi
Signed 16-bit Integer
The maximum antenna gain and spectral mask apply for all WLAN channels between the Start and Stop channels
Steve Shellhammer, Qualcomm Inc.

6. Proposal – Spectral Mask Representation
December 2011
Proposal – Spectral Mask Representation
The Spectral Mask is represented by a piecewise linear curve with the x-axis on a linear scale and the y-axis on a dB scale
The spectral mask field consist of a set of points
Each point consists of two fields
X dimension – Frequency in kHz (unsigned16-bit integer)
Y dimension – Spectral mask in 0.01 dB resolution (signed 16-bit integer) F1 M1 F2
Octets 2
Spectral Mask
Points M2 FN MN …
Spectral Mask Points
Meaning
Format Fn
Frequency value in kHz
16-bit unsigned integer Mn
Mask in 0.01 dB
16-bit signed integer
Steve Shellhammer, Qualcomm Inc.

7. December 2011
Illustration
(0,0)
(2500,0)
(2650,-20)
(3000,-35) P0 P1 P2 P3
Spectral Mask
Points
2500
2650
-2000
3000
-3500
In this example the spectral mask is normalized, but that is not required
Steve Shellhammer, Qualcomm Inc.

8. December 2011
Example
Steve Shellhammer, Qualcomm Inc.

9. Alternative Spectral Mask Representation
December 2011
Alternative Spectral Mask Representation
In the original spectral mask representation each point is represented by two numbers: frequency and mask. Both of those numbers are 16-bit signed integers
One method of requiring fewer bits is to use only an 8-bit number for the mask
Reducing to an 8-bit representation for the mask is accomplished by the following,
Scale the spectral mask so the maximum value is 0 dB
Reduce the mask resolution to 1 dB (versus the much higher 0.01 dB)
Represent the mask using an unsigned 8-bit number, which represents the negative of the mask
This new spectral mask representation requires only 3 octets for each point, versus 4 octets in the original spectral mask representation
Steve Shellhammer, Qualcomm Inc.

10. Proposal – Spectral Mask Representation
December 2011
Proposal – Spectral Mask Representation
The Spectral Mask is represented by a piecewise linear curve
The spectral mask field consist of a set of points
Each point consists of two fields
X dimension – Frequency in kHz (unsigned16-bit integer)
Y dimension – Spectral mask in 1 dB resolution (unsigned 8-bit integer) F1 M1 F2
Octets 2 1
Spectral Mask
Points M2 FN MN …
Spectral Mask Points
Meaning
Format Fn
Frequency value in kHz
16-bit unsigned integer Mn
Negative of Mask in dB
8-bit unsigned integer
Steve Shellhammer, Qualcomm Inc.

11. Illustration – Alternative Representation
December 2011
Illustration – Alternative Representation
(0,0)
(2500,0)
(2650,-20)
(3000,-35) P0 P1 P2 P3
Spectral Mask
Points
2500
2650 20
3000 35
Steve Shellhammer, Qualcomm Inc.

12. December 2011
Conclusions
Support for representation of both maximum antenna gain and spectral mask
Support for dependency on carrier frequency of both maximum antenna gain and spectral mask
Steve Shellhammer, Qualcomm Inc.

13. December 2011
References
Peter Ecclesine, “Spectrum Mask Descriptor Examples,” IEEE /1349r1, September 2011
Chen Sun, Zhou Lan, Yohannes Alemseged and Hiroshi Harada, “Network channel control with spectrum mask,” IEEE /1232r8, September 2011
Chen Sun, Zhou Lan, Yohannes Alemseged, Hiroshi Harada and Jens Tingleff, “Spectrum Mask Descriptor in TLV Format,” IEEE /1292r0, September 2011
Steve Shellhammer, Qualcomm Inc.