802.11n is the new generation WLAN technology promising significant improvement in throughput and useful range over legacy 802.11a,b,g equipment. In the home, 802.11n is expected to provide triple play coverage including video distribution through a typical house to multiple TV sets. In the enterprise/office environment, 802.11n is expected to support mission-critical applications with throughput, QoS and security rivaling 100Base-T.
The IEEE 802.11n standardization process is stable as the draft 2.0 has only minor changes from draft 1.0. The standard is scheduled to be ratified in 2H08 and compliance to the standard is expected to be achievable via software upgrade of existing silicon. The WLAN industry has embraced the 2.0 draft with the Wi-Fi Alliance beginning draft 2.0 product certification by mid-2007.
Draft 802.11n chipsets and equipment now available off-the-shelf show significant improvement over legacy 802.11a,b,g technology in terms of throughput and range (Figure 1).
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Figure 1 Representative throughput vs. range plots showing draft 802.11n's throughput improvement over legacy 802.11g technology.
This test focused on verifying the throughput and video performance vs. range of draft 802.11n equipment. The tests were performed in both office and home environments. The equipment was enabled with the most current software available from the vendors at the time of the tests. The eight AP/client pairs tested are listed in Table 1.
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Figure 2: Equipment used.
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Table 1: Equipment used.
The main objectives of the test were as follows:
- Measure and compare the throughput of the AP/client pairs in the home and office environments
- Measure and compare video prioritization performance of the AP/routers
- Measure throughput performance of the Gigabit Ethernet AP/routers between the WAN and the LAN ports.
- Analyze the competitive performance of the products from different vendors.
- Analyze differences in performance among the 2x2, 2x3 and 3x3 MIMO configurations.
An overview of the draft can be found in the following article: "Testing IEEE 802.11n," Test & Measurement World, April 2007, http://www.tmworld.com/article/CA6428547.html
In the last row and last column of Table 1, the third antenna in this case provides diversity; the chip only has 2 transmitters and 2 receivers. In contrast, the Atheros 3x3 device incorporates 3 transmitters and 3 receivers.