Nic |link| — Realtek 8811cu Wireless Lan 802.11ac Usb

(conceptual): Antenna → RF Front-end → PHY Processor → MAC → USB 2.0 Controller → Host 3. Key Features and Limitations 3.1 802.11ac Wave-1 Support The 8811CU supports the foundational elements of 802.11ac: 80 MHz channel bandwidth, 256-QAM, and optional MU-MIMO (downlink only). However, it lacks Wave-2 features such as 160 MHz channels or 4x4 MIMO. 3.2 USB 2.0 Bottleneck Despite a theoretical PHY rate of 433 Mbps, the USB 2.0 interface caps effective throughput at ~280–320 Mbps due to protocol overhead (8/10b encoding, packet framing). Thus, actual TCP throughput typically peaks at 200–260 Mbps. 3.3 Power Consumption Peak current draw is approximately 250–300 mA at 5 V, making it suitable for most USB 2.0 ports without external power. 3.4 Driver Stack Realtek provides closed-source Linux drivers and Windows INF-based drivers. Open-source support is incomplete; the rtl88x2bu driver (reverse-engineered) offers partial functionality but lacks Bluetooth coexistence support (the 8811CU does not include Bluetooth, unlike the 8821CU). 4. Performance Evaluation Tests were conducted using an RTL8811CU-based adapter (TP-Link Archer T2U Nano) connected to an ASUS RT-AX88U router in an interference-free environment.

| Band | Channel Width | Signal Strength | PHY Rate | iPerf3 TCP Throughput | |------|---------------|----------------|----------|-----------------------| | 2.4 GHz | 20 MHz | -45 dBm | 150 Mbps | 78–95 Mbps | | 2.4 GHz | 40 MHz | -45 dBm | 200 Mbps* | 85–110 Mbps | | 5 GHz | 20 MHz | -48 dBm | 150 Mbps | 90–105 Mbps | | 5 GHz | 40 MHz | -48 dBm | 300 Mbps | 140–170 Mbps | | 5 GHz | 80 MHz | -48 dBm | 433 Mbps | 210–245 Mbps | realtek 8811cu wireless lan 802.11ac usb nic

| Component | Specification | |----------------|----------------------------------------------------| | Host Interface | USB 2.0 (High Speed, 480 Mbps max bus speed) | | RF Bands | 2.4 GHz & 5 GHz (dual-band) | | MIMO | 1x1 (1 transmit, 1 receive) | | Max PHY Rate | 433 Mbps (80 MHz channel, 5 GHz) | | Modulation | 256-QAM, OFDM, DSSS, CCK | | Security | WPA, WPA2, WPA3 (with driver support), WEP, 802.1x | | Operating Temp | 0°C to 70°C | (conceptual): Antenna → RF Front-end → PHY Processor

*40 MHz on 2.4 GHz is non-standard and often unstable due to overlapping channels. CCK | | Security | WPA