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multiple antenna system

To achieve higher received field strengths and data rates in radio systems, spatial diversity is a technique that uses multipath propagation of radio signals, spatial multiplexing or diversity methods, or antenna arrays on the transmitting and receiving sides, multiple antenna systems or smart antennas.

In general, radio transmission between a transmitter and a receiver takes the form of the transmitter radiating the RF signal from an antenna and the receiver having an antenna for reception. For such systems there is the acronymSISO, which stands for Single Input Single Output.

Multi-antenna systems

Multi-antenna systems

An increase in the received field strength can already be achieved by two or more receiving antennas. This is known as Single Input Multiple Output( SIMO). If several antennas are used to radiate the RF signal instead of one transmitting antenna, the antenna systems are called Multiple Input Single Output( MISO), and if several antennas are used for both the transmitting side and the receiving side, this is called Multiple Input Multiple Output( MIMO).

Transmitting and receiving with multiple antenna systems

Transmitting and receiving with multiple antenna systems

In multi-antenna systems, all transmitters send signals to all receivers. Thus, in a three-antenna system, the first receiving antenna receives the sum of signal components h11, h12, and h13, the second receives h21, h22, and h23, and the third receiving antenna receives components of h31, h32, and h33. If the matrices are known, then the transmit signals can be calculated from them. The matrix elements are regularly measured and optimized by a pilot tone. This is necessary because the transmission on the radio link and thus the reception conditions may have changed.

With these multi-antenna systems, the bandwidth can be used more efficiently and the data rate can be increased to 20 bit/ Hz to 40 bit/Hz.

Informations:
Englisch: multiple antenna system
Updated at: 03.12.2012
#Words: 288
Links: field, data, diversity, multipath propagation, spatial multiplexing (SM)
Translations: DE
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