Description meanings

[jdhurst]

Hello

What does 2x2 or 3x3 mean in 12.1" WXGA (1280x800) LED Panel, 2x2 ? 2x2 includes Camera, 3x3 does not.

Similarly what does 2x2 mean in Intel Centrino Advanced-N 6200 (2x2 AGN) or 3x3 in Intel Centrino Ultimate-N 6300 (3x3 AGN)

Also, my experince with Vista (this T61p I have) was that the Thinkpad wireless was very bad, whereas my current Intel card (Vista or Windows 7) is excellent. This is the reverse of my experience with the Thinkpad card on my T41 XP machine (excellent) and older Intel (bad).

I now prefer Intel. On an X201, is there any reason to choose Thinkpad over Intel? And on an X120, there is no Intel option.

Thanks, .... JDH

[EOMtp]

MIMO systems employ multiple antennas at the transmitter (tx) and receiver (rx), which significantly increases data rates, range, and reliability without the need for adding bands or transmit power. These benefits are achieved via the spatial dimension associated with the multiple antennas. Specifically, multiple antennas at both the transmitter and the receiver can create multiple independent channels for sending multiple data streams.

The number of independent data streams that can be supported over a MIMO channel is determined by the number of antennas at the transmitter and the receiver. A 2x2 system can support two streams, and a 3x3 system can support three streams. There is also a 4x4 system which can support four streams.

Furthermore, dynamic digital beam-forming and MIMO receiver processing can combine independent streams in order to increase reliability and range.

Returning to nomenclature:
-- 2x2 means 2 antennas, using 2tx and 2rx
-- 3x3 means 3 antennas, using 3tx and 3rx ..or.. 2tx and 3rx (vendor-specific)
Therefore, maximum 3 antennas for 3x3, and maximum 2 antennas for 2x2.

Here is how the above applies to 802.11a/b/g/n data rates:
http://www.intel.com/support/wireless/w ... 025321.htm

[jdhurst]

Thank you for this.

It appears that a 3x3 lid without camera can support a 3x3 wireless card. But then it would also appear that a 2x2 lid with camera cannot support a 3x3 wireless card.

I am a while away from buying a new machine, so I will keep track of this.

Best regards. .... JDH

[erik]

a 2x2 lid can "support" a 3x3 card but will only have two antennas connected as a result.   a 3x3 card will run perfectly fine with only two antennas -- it simply won't reach full speed (300 Mbps vs. 450 Mbps).

the CTO system didn't used to allow 3x3 cards configured with 2x2 lids but that has since changed.

personally, i would take an intel 6300 over a 62xx regardless of the lid configuration.   the 6300 arguably works better all around.