I am currently customizing a Lenovo Thinkpad.
Under the section “
Integrated WiFi wireless LAN adapters” there are two options.Default: ThinkPad 1x1 b/g/nUpgraded: ThinkPad 2x2 a/b/g/n (+$10 AUD)What does the 1×1 and 2×2 mean?
For reference, here is the link. 5th option from the bottom.Customize Lenovo Thinkpad
Solution:
That’s a no-brainer. Pay the +$10 AUD and get the 2×2 a/b/g/n. It can move data at up to twice the speed of the “1×1 b/g/n” solution, and it supports the much larger, less congested 5GHz frequency band, making it less likely to interfere with (or receive interference from) all the other uses of the 2.4GHz band.
1×1 and 2×2 refer to the number of transmit and receive radio chains built into the Wi-Fi card. 2×2 means it has two transmit and two receive radio chains, and usually implies that it supports 2 “spacial streams”, which is a key way that 802.11n is faster than the previous generation of Wi-Fi technologies. 802.11n is the first standard in the 802.11 family to support MIMO (pronounced “MY-moh”), which stands for “Multiple Inputs, Multiple Outputs”, which is basically a way of ganging together multiple radios to get faster data rates than you can get with a single radio on each end of the connection. Because it’s possible to create a wireless card with 2 transmit and 2 receive radio chains but still not do real 2 spacial stream MIMO, some people in the industry now use the notation TxR:S, where T is the number of Transmit radio chains, R is the number of Receive radio chains, and S is the number of supported “spacial streams”.
Because MIMO was the raison d’être for 802.11n, when the first N gear hit the market in 2007, it was all 2×2:2, which means it can support up to 300 megabit per second data rates when used with 40MHz-wide channels.
Unfortunately, within the last year or so, some companies have been being cheap, and, in my opinion, a bit deceptive, and selling 1×1:1 radios as 802.11n. Technically they do support a few of the slowest 802.11n-style modulation schemes, but since they only have a single transmit and receive radio, they aren’t MIMO, and 802.11n without MIMO is like a BLT without bacon.
The maximum data rate a 1×1:1 radio can get is 150 megabits per second, and that’s when using a 40MHz-wide channel (sometimes called simply a “wide channel”, because before 802.11n, all standard 802.11 channels were never wider than about 20 or 22MHz). Wide channels are fine in the 5GHz band which is a much larger band with a lot more channels and a lot less congestion than the old 2.4GHz band. But in the 2.4GHz band, using wide channels can cause problems because it takes up like two-thirds of the entire band, leaving very little room for things like Bluetooth and neighboring 802.11 networks. Unfortunately, that 1×1 solution is only b/g/n and doesn’t say “a”, which implies it ONLY supports the small, congested 2.4GHz band.
The 2×2 solution says it supports “a” (802.11a), which only worked in the 5GHz band, which means that radio is 5GHz capable. Since it also lists b and g, you know it’s 2.4GHz capable. Also, because it’s almost certainly a 2×2:2, it can almost certainly use signaling rates up to 300 megabits per second.