How the Number of Antennas Affect Wireless Router Performance (MIMO)?

At the time when Wireless vendors introduced the wireless router in market, most of the devices had one antenna. That means the single antenna would send and receive wireless signals. However, now it is the time of Multiple Input Multiple Output technology. In MIMO (short form of Multiple Input Multiple Output), AP (Access Point) is able to send and receive wireless signals over multiple antennas. This feature improved the efficiency of the Wireless router compared to traditional single antenna routers.
How the Number of Antennas Improves Signal Quality
There are many factors which affect quality of the signal. Those factors include:
1. Wireless Range
2. Interference
3. Echo handling
4. Wireless Bandwidth
1. Range
Range is a very important factor. To improve the wireless range of an Access Point either we can use a powerful antenna or use multiple ordinary antennas. experiments say it is wise to use multiple antennas instead of using single powerful antenna. Here MIMO plays a big role in increasing the signal-range as MIMO lets the AP use multiple channels.
2. Avoid Interference
We are using many devices which emit wireless signals. So there is a chance of interference which can badly affect quality of AP. Using multiple channels we can reduce the chances of possible interference with other wireless devices.
3. Echo handling
Another important point we should consider while using wireless router is the possibility of echo. Echo can reduce the performance of the device and the quality of the network. Echo badly affect the signal we receive and its quality will be less than actually it meant for. AP needs at least three antennas to reduce the effect of echo.
4. Bandwidth
MIMO has a vital role in improving the bandwidth.
Which Wireless Standards support MIMO
Practically IEEE802.11n standard supports Multiple Input Multiple Output Standard. So we can see all the multiple antenna routers belongs to wireless n standard. In addition to 802.11n, MIMO is supported by 4G, WiMAX, HSPA+ etc. It shows future technologies cannot avoid the use of Multiple Input Multiple Output technology.
Predecessors of MIMO
MIMO is not a Standalone technology. It comes from a set of standards. They are:
1. SISO
2. SIMO
3. MISO
In SISO (Single Input Single Output) AP does not have multiple channels to receive and send signal. In SIMO (Single Input Multiple Output) device can transmit signal through single channel only. MISO (Multiple Input Single Output) is opposite to SIMO where device can transmit though multiple channels. So we can see MIMO is derived by combining the SISO, SIMO and MISO standards.