General Description - Realtek RTL8812AE User Manual

RTL8812AE
Half Mini-Card User Manual

1. General Description

The Realtek RTL8812AE is a highly integrated single-chip MIMO (Multiple In, Multiple Out) Wireless LAN
(WLAN) PCI Express network interface controller complying with the wireless very high throughput IEEE
802.11ac Draft 2.0 and high throughput 802.11n specification. The RTL8812AE provides a complete solution
for a high-performance wireless client and also supports WiFi Direct feature that can easily build a WiFi P2P
PAN network.
The RTL8812AE baseband implements Multiple Input, Multiple Output (MIMO) Orthogonal Frequency
Division Multiplexing (OFDM) with two transmit and two receive paths (2T2R). Features include two spatial
stream transmissions, short Guard Interval (GI) of 400ns, spatial spreading, and support for 20MHz, 40MHz
and 80MHz channel bandwidth. Moreover, RTL8812AE provides one spatial stream space-time block code
(STBC), Transmit Beamforming (TxBF) and Low Density Parity Check (LDPC) to extend the range of
transmission. At the receiver, extended range and good minimum sensitivity is achieved by having receiver
diversity up to 2 antennas. As the recipient, the RTL8812AE also supports explicit sounding packet feedback
that helps senders with beamforming capability. With 2 independent RF blocks, the RTL8812AE can perform
fast roaming without link interruption.
For legacy compatibility, Direct Sequence Spread Spectrum (DSSS), Complementary Code Keying (CCK) and
OFDM baseband processing are included to support all IEEE 802.11b, 802.11g and 802.11a data rates.
Differential phase shift keying modulation schemes, DBPSK and DQPSK with data scrambling capability are
available, and CCK provides support for legacy data rates, with long or short preamble. The high speed
FFT/IFFT paths, combined with BPSK, QPSK, 16QAM, 64QAM and 256QAM modulation of the individual
subcarriers, and rate compatible coding rate of 1/2, 2/3, 3/4, and 5/6, provide up to 866.7Mbps for IEEE
802.11ac MIMO OFDM.
The RTL8812AE builds in an enhanced signal detector, an adaptive frequency domain equalizer, and a
soft-decision Viterbi decoder to alleviate severe multi-path effects and mutual interference in the reception of
multiple streams. For better detection quality, receive diversity with Maximal-Ratio-Combine (MRC) applying
up to two receive paths is implemented. Robust interference detection and suppression are provided to protect
against Bluetooth, cordless phone, and microwave oven interference.
Receive vector diversity for multi-stream application is implemented for efficient utilization of the MIMO
channel. Efficient IQ-imbalance, DC offset, phase noise, frequency offset, and timing offset compensations are
provided for the radio frequency front-end. Selectable digital transmit and receive FIR filters are provided to
meet transmit spectrum mask requirements and to reject adjacent channel interference, respectively.
The RTL8812AE supports fast receiver Automatic Gain Control (AGC) with synchronous and asynchronous
control loops among antennas, antenna diversity functions, and adaptive transmit power control functions to
obtain better performance in the analog portions of the transceiver.
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