BCM4319 Preliminary Data Sheet
PHY Features
The PHY has been designed to work with interference, radio nonlinearity, and impairments. It incorporates
efficient implementations of the filters, fast fourier transform (FFT), and Viterbi-decoder algorithms. Efficient
algorithms have been designed to achieve maximum throughput and reliability, including algorithms for carrier
sense/rejection, frequency/phase/timing acquisition and tracking, and channel estimation and tracking. The
PHY receiver also contains a robust 11b demodulator. The PHY carrier sense has been tuned to provide high
throughput for 802.11g/11b hybrid networks with Bluetooth coexistence. It has also been designed for shared
single antenna systems between WLAN and BT to support simultaneous Rx-Rx. In dual antenna designs, the
digital PHY has been designed for Maximal Ratio Combining (MRC) in RF.
Figure 15: WLAN PHY Block Diagram
CCK/DSSS
Demodulate
Filters and
Radio
Comp
Frequency
and Timing
Synch
Descramble
and Deframe
OFDM
Viterbi
Decoder
Demodulate
Carrier Sense,
AGC, and Rx
FSM
Radio
Control
Block
Buffers
FFT/IFFT
MAC
Interface
AFE
and
Radio
Tx FSM
Modulation
and Coding
Common Logic
Block
Frame and
Scramble
Filters and
Radio Comp
Modulate/
Spread
PA Comp
COEX
The PHY is capable of fully calibrating the RF front end to extract the highest performance. On power-up, PHY
calibrations correct for IQ mismatch and local oscillator leakage. PHY periodic calibrations compensate for
temperature related drift to yield high performance over time. A closed-loop transmit control algorithm maintains
the output power to a fixed level with the capability to control Tx power on a per packet basis.
The PHY can receive two spatial streams. The STBC scheme can obtain diversity gains by using multiple
transmit antennas at the access point (AP) in a fading channel environment, without increasing the complexity
at the station (STA). Details of STBC reception are shown in Figure 16 on page 41.
Broadcom®
Single-Chip IEEE 802.11™ a/b/g/n MAC/Baseband/Radio
Page 40
April 2, 2014 • 4319-DS05-R
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