Bluetooth is also used for a variety of wireless devices on PCs, including printer adapters, keyboards, mice, headphones, DV camcorders, data projectors, and many others. 802.11n hardware uses chips from makers including Atheros, Broadcom, Cisco, Intel, Marvell, and Ralink.īluetooth is a low-speed, low-power standard originally designed to interconnect laptop computers, PDAs, cell phones, and pagers for data synchronization and user authentication in public areas such as airports, hotels, rental car pickups, and sporting events. As with previous Wi-Fi certifications, the Wi-Fi 802.11n certification requires that hardware from different makers interoperate properly with each other.
#RALINK WIRELESS LAN CARD UPLOAD SPEED DRIVER#
In some cases, driver or firmware updates might be necessary to insure ensure full compliance. The 802.11n standard was finally published in October 2009, and 802.11n Draft 2 or later products are considered to be compliant with the final 802.11n standard. The Wi-Fi Alliance first began certifying products that support 802.11n in its Draft 2 form in June 2007. Because there are no devices on the market that support four streams, the maximum throughput advertised by Wireless-N devices today is either 300 Mb/s (using two streams) or 450 Mb/s (using three streams), and those figures also assume both the use of 40 MHz wide channels (not normally recommended) and a short guard interval.
The following table compares the standard and optional speeds supported by 802.11n to those supported by 802.11b, 802.11a, and 802.11g.Īs you can see from the table, Wireless-N devices supporting four data streams will be able to support up to 600 Mb/s throughput, however the reality today is much less than this. As with other members of the 802.11 family of standards, 802.11n supports fallback rates when a connection cannot be made at the maximum data rate. Using the shorter 400 ns guard interval would increase this to up to 216.7 Mb/s. However, in the real world the shorter guard interval doesn’t normally cause problems, so it is enabled by the default configuration in most devices.Ĭombining the use of three data streams using standard 20 MHz channels and the standard 800 ns guard interval, the maximum throughput of a Wireless-N connection would be 195 Mb/s. Just as with channel bonding (40 MHz channel width), this can cause problems if there is excessive interference or low signal strength, resulting in decreased overall throughput due to signal errors and retries.
By decreasing the guard interval from the standard 800 ns to an optional 400 ns, the maximum bandwidth increases by about 10%. In the real world I’ve seen throughput decrease dramatically with 40 MHz channels, such that the use of 40 MHz channels is disabled by default on most devices.Īnother optional feature is using a shorter guard interval (GI), which is the amount of time (in nanoseconds) the system waits between transmitting OFDM (orthagonal frequency division multiplexing) symbols in a data stream. In addition, the wider channel takes up more of the band, causing more interference with other wireless networks in range. I say “in theory” because using the wider channels works well under very strong signal conditions, but can degrade rapidly under normal circumstances. By using channel bonding to increase the channel width to 40 MHz, more than double the bandwidth can be achieved in theory. The base configuration uses 20 MHz wide channels with an 800 ns guard interval between transmitted signals. The highest performance Wireless-N devices generally available on the market today use a 3 x 3:3 radio configuration, which supports three data streams for up to 450 Mb/s in bandwidth.Ĩ02.11n is significantly faster than 802.11g, but by how much? That depends mainly on how many data streams are supported, as well as whether a couple of other optional features are enabled or not. Those using more antennas than data streams allow for increased signal diversity and range. Other common configurations include 2 x 2:2, 2 x 3:2, and 3 x 3:2, which include radios with 2 or 3 antennas supporting up to two data streams for up to 300 Mb/s in bandwidth. Common configurations that are used in Wireless-N devices include 1 x 1:1, 1 x 2:1, and 2 x 2:1, which include radios with 1 or 2 antennas supporting only a single data stream for up to 150 Mb/s in bandwidth. The maximum performance configuration supported by the standard is 4 x 4:4, (4 transmit/receive antennas and 4 data streams), which would support bandwidths of up to 600 Mb/s, however no devices are currently on the market using that configuration.
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