RTL8191RU
User’s Manual
1. General Description
The Realtek RTL8191RU USB module is a highly integrated MIMO wireless LAN (WLAN) used for high
speed wireless local network access. The card is built with a MAC and 1T2R capable RF/baseband single
chip RTL8191RU.
The RTL8191RU USB module implements multiple input, multiple output (MIMO) orthogonal frequency
division multiplexing (OFDM) with 1 transmit and 2 receive paths and is compatible with 802.11n Draft
specification 2.0. Other features include two spatial streams transmission, Long guard interval (GI) of
800ns, spatial spreading, and transmission over 20 MHz and 40 MHz bandwidth. Moreover, RTL8191RU
provides one spatial stream space-time block code (STBC) 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 RTL8191RU USB module also supports explicit sounding packet feedback
that helps senders with beamforming capability.
For legacy compatibility, direct sequence spread spectrum (DSSS), complementary code keying (CCK)
and OFDM baseband processing are included to support all 802.11b, and 802.11g data rates. Differential
phase shift keying modulation schemes, DBPSK and DQPSK with data scrambling capability, are available
along with complementary code keying to provide the data rates of 1, 2, 5.5 and 11Mbps with long or short
preamble. The high speed FFT/IFFT paths, combined with BPSK, QPSK, 16QAM, and 64QAM
modulation of the individual subcarriers and rate compatible punctured convolutional coding with coding
rate of 1/2, 2/3, 3/4, and 5/6, provides the maximum data rate of 54 Mbps and 300 Mbps for IEEE 802.11g
and 802.11n MIMO OFDM respectively.
The RTL8191RU USB module supports 802.11e for multimedia applications, 802.11i for security, and
802.11n for enhanced MAC protocol efficiency. Using packet aggregation techniques such as A-MPDU
with BA and A-MSDU, protocol efficiency is significantly improved. Power saving mechanisms such as
U-APSD, APSD, and MIMO power saving reduces the power wasted during idle time, and compensates for
the extra power required to transmit MIMO OFDM. The RTL8191RU USB module provides simple legacy
and 20Mhz/40Mhz co-existence mechanisms to ensure backward and network compatibility.
4 Rev.1.0
