* Chipmaker shares sample rates based on performance modeling
Draft 2.0 802.11n network performance is dependent on so many variables that it can be challenging to get your head around just what to expect with the next-generation Wi-Fi LAN systems. However, Wi-Fi chipmaker Atheros has shared some ballpark throughput numbers based on hypothetical modeling it has conducted in-house.
The table provides estimates of the downlink throughput likely to be realized in Atheros-based networks at various distances and depending on how many antennas and spatial streams are in play. The lion’s share of Wi-Fi systems use Atheros chipsets; many also use the Atheros reference design. Cisco is a notable exception.
802.11n: Approximate Performance and Coverage | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
* Number of antennas on transmitting device times number of antennas on receiving device **Not yet available in commercial product *** Downlink speeds; environment-dependent; based on hypothetical 802.11n modeling Source: Atheros | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
In addition to the core chips and system implementation, some other key contributors to actual throughput include the following:
* Architecture of the WLAN system.”MIMO, antennas and streams – oh, my!” and “What 802.11n tech specs mean”).
* The mix of clients in your environment and their degree of “stickiness.”
* The mix of mandatory and optional 802.11n features supported in the pre-standard 802.11n devices you use.
* How many antennas are used in the system and how many spatial streams are supported (see
* Whether you operate in 40MHz dual-channel mode or in 20MHz single-channel mode.
* Whether 11n APs are serving 802.11a, b or g clients as well as n clients.
And so on. In the coming months, we’ll take a look at each of these items a bit more under the microscope.
