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Figure 2.8 LinkSys Wireless-N USB Network Adapter
Figure 2.9 Wireless Communications Using the WUSB-N Wireless Adapter
2.2.3 Wireless Router
Another configuration for our wireless testing is to communicate between the RSE and OBE
though a private network. A LinkSys WRT310N wireless router as shown in Figure 2.10 was used as
a gateway to test the data communication between the embedded target computers. According to the
product specification from LinkSys (http://www.linksys.com/), the access point built into the
WRT310N router uses the Wireless-N (draft 802.11n) wireless networking technology. The IEEE
802.11n builds on previous 802.11 standards by adding multiple-input multiple-output (MIMO) and
40 MHz operation to the physical (PHY) layer. MIMO uses multiple transmitter and receiver
antennas to improve the system performance. The 40 MHz operation uses wider bands, compared to
20 MHz bands in previous 802.11 operations, to support higher data rates. Wider bandwidth channels
are cost effective and easily accomplished with moderate increases in digital signal processing.
By overlaying the signals of multiple radios, WRT310N router's MIMO technology multiplies the
effective data rate. Unlike ordinary wireless networking technologies that are confused by signal
reflections, MIMO actually uses these reflections to increase the range and reduce "dead spots" in the
wireless coverage area. The robust signal travels farther, maintaining wireless connections much
farther than standard Wireless-G. The Wireless-N USB adapters were used to evaluate the
performance of the wireless router in the outdoor environment. The RSE and OBE were each
connected to the wireless-N adapters and established communications to each other through the
WRT310N access point as illustrated in Figure 2.11.
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