12 Designing for Next Gen Wi-Fi Applications
QPF4230 Wi-Fi Front End
Modules (FEMs)
QPF4230EVB-01 Evaluation Board
• 2412MHz to 2484MHz operating
frequency range
• Optimized for 3.3V operation
• 15dB Rx gain and 6dB bypass loss
• Designed to evaluate the QPF4230 Wi-Fi FEM
• 2412MHz to 2484MHz operating frequency
range
• For use in wireless routers, access points
and IoT applications
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Figure 1 OFDM vs OFDMA resource allocation
Wi-Fi 6 or 802.11ax Standard
802.11ax is the sixth generation of Wi-Fi, built on the
strengths of 802.11ac, which provides more wireless
capacity and reliability. 802.11ax achieves these benefits
by using denser modulation (1024QAM), (OFDMA), reduced
subcarrier spacing (78.125kHz) and using scheduled-based
resource allocation.
Unlike 802.11ac, 802.11ax is a dual-band 2.4GHz and
5GHz technology. 802.11ax was designed for maximum
compatibility, coexisting efficiently with 802.11a/g/n/ac
clients. 802.11ax uses OFDMA, which allows resource units
(RUs) that divide the bandwidth according to the needs
of the clients and provides multiple individuals with the
same user experience at faster speeds. With 802.11ac,
the Wi-Fi channel was broken down into a collection of
smaller OFDM sub-channels. For OFDM, at any given point,
the individual subcarriers are all part of one protocol data
unit (PPDU). However, with OFDMA (802.11ax), individual
groups of subcarriers are individually allocated to clients
as resource units on a per-PPDU basis (Figure 1). However,
with OFDMA (802.11ax), individual groups of subcarriers
are individually allocated to clients as resource units on a
per-PPDU basis (Figure 1).
Earlier 802.11 standards used CSMA/CA method. This
method allowed the wireless clients to first sense the
channel to avoid collisions, thereby only transmitting when
the channel is idle. Although this clear assessment and
collision avoidance serves well, its efficiency decreases
when the number of clients grows very large.
This method allowed the
wireless clients to first sense
the channel to avoid collisions,
thereby only transmitting when
the channel is idle.
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