Wireless LAN USB 2.0 Network Interface Controller
The Realtek RTL8187B is a low-profile highly integrated cost-effective Wireless LAN USB 2.0 network interface controller that integrates a USB 2.0 PHY, SIE (Serial Interface Engine), 8051 MCU, a Wireless LAN MAC, and a Direct Sequence Spread Spectrum/OFDM baseband processor onto one chip. It provides USB high speed (480Mbps), and full speed (12Mbps), and supports 9 endpoints for transfer pipes. To reduce protocol overhead, the RTL8187B supports Short InterFrame Space (SIFS) burst mode to send packets back-to-back. A protection mechanism prevents collisions among 802.11b nodes. The RTL8187B fully complies with IEEE 802.11a/b/g, WMM, 802.11e, and CCX specifications.
To reduce protocol overhead, the RTL8187B supports Short InterFrame Space (SIFS) burst mode to send packets back-to-back. A protection mechanism prevents collisions among 802.11b nodes.
Direct Sequence Spread Spectrum (DSSS), Complementary Code Keying (CCK), and Orthogonal Frequency Division Multiplexing (OFDM) baseband processing are implemented to support all IEEE 802.11a, 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 data rates of 1, 2, 5.5, and 11Mbps, with long or short preamble. A high-speed Fast Fourier Transform (FFT)/Inverse Fast Fourier Transform (IFFT), combined with BPSK, QPSK, 16QAM and 64QAM modulation of the individual sub-carriers, provides data rates of 6, 9, 12, 18, 24, 36, 48 and 54Mbps, with rate-compatible punctured convolutional coding with a coding rate of 1/2, 2/3, and 3/4.
An enhanced signal detector, an adaptive frequency domain equalizer, and a soft-decision Viterbi decoder are built-in to alleviate severe multipath effects. Efficient IQ-imbalance calibration, DC offset, phase noise, frequency offset, and timing offset compensation reduce radio frequency front-end impairments. Selectable digital transmit and receiver FIR filters are provided to meet the requirements of transmit spectrum masks, and to reject adjacent channel interference, respectively. Both in the transmitter and receiver, programmable scaling in the digital domain trades the quantization noise against the increased probability of clipping. Robust signal detection, symbol boundary detection, and channel estimation perform well at the minimum sensitivity.
The RTL8187B supports fast receiver Automatic Gain Control (AGC) and antenna diversity functions, and an adaptive transmit power control function to obtain better performance in the analog portions of the transceiver. It also has on-chip digital-to-analog converters and analog-to-digital converters for analog I and Q inputs and outputs, transmit TSSI and receiver RSSI inputs, and transmit and receiver AGC outputs.
The RTL8187B keeps network maintenance costs low and eliminates usage barriers. The RTL8187B is highly integrated and requires no ‘glue’ logic or external memory.