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11n standard uses OFDM modulation and is therefore perfectly legal to operate these facilities under the general authority as 11a/b/g.
The speed at which the devices communicate determine the so-called modulation schemes and code MSC. These are defined total 31st
MSC 0-7 uses one antenna to transmit and receive (so-called single stream) It is possible to have a standard width of 20 MHz channel, but for higher speed is selected to be 40 MHz. MSC7 theoretical maximum speed of 150 Mbps and is used only one antenna. Real rates are above 70 Mbps, but we'll see how it will be in our other tests.
MSC 8-15 adds MIMO (Multile Input Multiple Output), it is the use of multiple antennas on both sides. These schemes specifically 2 antennas (known as MIMO 2x2). Not so that one antenna transmits and one receives, but always send and receive both antennas. Is used here to increase the speed of phase shifts (very simply say). These schemes used innovations products such as MIMO Junior, MIMO Station, Wodasign 11N router and a theoretical maximum speed is 300 Mbps. The measurements we showed that it is preferable to using separate antennas use different pairs of polarization antennas. The new MIMO antenna BOX, DUPLEX JIROSU or AirMAX from UBNT already own 2 antennas have, so just connect using the equipment. Indicates the maximum real rate of about 150 Mbps. We measured a short distance where the max speed of just under 100 Mbps. Detailed we measured the links at around 200 to 600 meters and the speed is always around 75 Mbps full duplex. Detailed measurements on links 2 to 4 km you can see on http://www.cpx.cz/dls/wp543-MIMO%20series/2-2.5Km%20COMPEX%2-
0MIMO%20Test%20Results.xls
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