ITU-T G.9959 PHY shall employ frequency shift keying (FSK) for RF modulation at data rates R1 and R2. The PHY shall employ Gaussian frequency shift keying (GFSK) for RF modulation at data rate R3. Manchester code shall be used for data symbol encoding at data rate R1 and non-return-to-zero (NRZ) shall be used for data symbol encoding at data rates R2 and R3.
The modulation and the coding format are summarized in table below.
|
Data Rate |
Modulation |
Coding |
Frequency Offset |
Separation |
Symbols |
|---|---|---|---|---|---|
|
R1 |
FSK |
Manchester |
20 kHz |
40 kHz ±20% |
Binary |
|
R2 |
FSK |
NRZ |
0 kHz |
40 kHz ±20% |
Binary |
|
R3 |
GFSK, BT = 0.6 |
NRZ |
0 kHz |
58 kHz ±20% |
Binary |
The general PPDU frame structure is outlined in figure below. The frame format is depicted in the order in which it is transmitted by the PHY, from left to right, where the leftmost bit is transmitted first in time. The preamble field shall be composed of a sequence of bytes containing the binary pattern "01010101". The SOF field is configurable in the software and default value is 0xF0.
The PHY payload part, PSDU consists of fields that are configurable with the software. The following figure shows these fields.
The MHR (MAC Header) field uses a dialog box in the software to figure its values. Use the MAC Header (hex) check box to either turn the header on or off. The fields are only configurable with the header on (check box checked).
