Among the physical layers, .11, .11b, .11a, .11g and Draft n offer progressive speeds over the course of development, which are as follows
Standard | Year | Modulation | Peak Rate | Peak Throughput |
.11 | 1999 | DSSS | 2 Mbps | 1 Mbps |
.11b | 1999 | CCK | 11 Mbps | 6 Mbps |
.11a | 1999 | OFDM | 54 Mbps | 25 Mbps |
.11g | 2003 | OFDM | 54 Mbps | 22 Mbps |
Draft n | 2006 | MIMO OFDM | 300 Mbps | 180 Mbps |
Also available are security features vital to wireless protection; QoS support that improves the service quality when service compromise becomes inevitable; radar detection that avoids interference with airport or weather Radar operations.
Users should evaluate application needs carefully and tailor the product appropriately. A sample of video application requirements are listed as follows:
Application | Throughput |
SDTV | 5 Mbps |
Cable Modem | 6 Mbps |
DVD | 9.8 Mbps |
HDTV | 12.9 Mbps |
ADSL2+ | 20 Mbps |
FTTH | 30 Mbps |
HD DVD | 36 Mbps |
Blue-ray DVD | 48 Mbps |
VDSL | 50 Mbps |
Video streaming is very demanding in frame errors, e.g., FER < 10-4 or tighter, so the peak throughput of a specific WLAN device is recommended to scale down to one-third of its original value for budgetary purposes. For example, a peak throughput of 15 Mbps is necessary for satisfactory SDTV streaming at 5 Mbps in general.
Ralink offers a full array of WLAN products including the latest Draft-n chipset. Peak throughput exceeds 180 Mbps in lab tests, which meets all of the above video application requirements with ease.
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