Keysight WLAN Measurement Guide 97
Concepts
Digital Modulation Format Standards
Digital Modulation Format Standards
Introduction
This section introduces digital modulation formats supported by WLAN
standards.
The RF carrier(s) must be modulated. All the WLAN systems described in this
book use a form of phase-shift keying for the preamble. More complex
schemes, such as 64QAM (Quadrature Amplitude Modulation) give faster bit
rates for user data, but require better radio performance and less noise to work
to their full potential. BPSK (Phase Shift Keying), QPSK, and QAM are
described in standard RF texts. Often the modulation format changes during
the transmission. This is because the early part of the burst contains important
information about the burst, including analog characteristics such as
frequency, and digital information such as burst length. Simpler modulation
formats are less prone to bit errors, and thus are more suitable to use early in a
burst.
Modulation Formats and WLAN standards
Table below shows modulation formats supported in WLAN measurement
application, grouped by the IEEE standards.
Table 3-6
Families of Digital Modulation Formats
WLAN Standard
Carrier Type
Modulation Format
802.11a
OFDM
BPSK
QPSK
16 QAM
64 QAM
802.11b
DSSS
DSSS 1 Mbps
DSSS 2 Mbps
CCK 5.5 Mbps
CCK 11 Mbps
PBCC 5.5 Mbps
PBCC 11 Mbps