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MIMO naming convention

Started by Sharan123 7 years ago3 replieslatest reply 7 years ago230 views

The MIMO naming convention seems confusing to me.

  1. SISO – Single Input Single Output system – 1 1 Tx antenna , 1 1   Rx antenna
  2. SIMO – Single Input Multiple Output system – 1 1   Tx antenna, N R  NR Rx antennas (N R >1 NR>1 )
  3. MISO – Multiple Input Single Output system – N T  NT Tx antennas, 1 1   Rx antenna   (N T >1 NT>1 )
  4. MIMO – Multiple Input Multiple Output system – N T  NT Tx antennas, N R  NR Rx antennas (N T ,N R >1 NT,NR>1 )

In the above MIMO type 2 (SIMO), the name is single input and multiple output. So, I basically, assumed from a perspective of a given system, he has 1 RX antenna and N transmit antenna. That is, transmit by the given system counterpart. E.g. if a given system is an UE then counterpart would be a base station.

But the above definition says SIMO as 1 TX antenna and N rx antenna. So, what is the meaning of input and output in these defnitions?

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Reply by SlartibartfastFebruary 16, 2017

Actually that's backwards.   The terminology is from the perspective of the channel, so Single Input Multiple Output means that there is a single transmit antenna and multiple receive antennas in a particular link.   An example would be a single antenna transmitter sending a signal to a receiver with diversity reception.

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Reply by Sharan123February 16, 2017

Thanks a lot ... this really helps

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Reply by jithinrjFebruary 16, 2017

When you say system, it includes both UE and Base station. I feel it is wrong to isolate one of them and call it a system. One of the main aspect of this system is that a UE or a BS can only perform a transmission or reception at a time - they cannot do both. One node will be output (transmitter) and another will be input (receiver). In this case, if you view from the perspective of a channel, a SIMO system gives single output from node and gives it to the channel (single input). The channel multiplies it into N channels and outputs it from the channel (multiple output). This is input to the N antennas. Hence, the MIMO system is coined from the point of view of channel. If the UE -> BS link is SIMO (1xN), the counterpart (BS -> UE) is MISO (Nx1).