Single Input Single Output (SISO) systems: Transmitter and receiver both having single antenna.

Single Input Multiple Output (SIMO) systems: It is a case of receive diversity where transmitter is equipped with one antenna and receiver has multiple antennas. It is used in Uplink transmission. In this systems,

various combining schemes like Maximum Ratio Combing (MRC) and Equal Gain Combing (EGC) are used.

Multiple Input Single Output (MISO) systems: It is a case of transmit diversity where transmitter has multiple antennas and receiver has a single antenna . It is used in downlink transmission. In this systems, two

transmission schemes are used like transmit beamforming and space time coding.

Multiple Input Multiple Output (MIMO) systems: It is a combined case of

transmit-receive diversity, where multiple antennas are there at both the ends

• Single–input-single-output (SISO):

SISO techniques have a single input signal and a single output signal.

• Single–input-multiple-output (SIMO):

SIMO techniques have a single input signal (the transmitter has a single antenna) and more than one output signal.

• Multiple –input- single -output (MISO):

MISO techniques have multiple input signals and a single output signal (the receiver has a single antenna).

• Multiple-input-multiple-output (MIMO):

MIMO techniques have multiple input and output signals, and form the most general of the four classes. They have dual capability of combining the SIMO and MISO technologies.

Just completing what was already said, it is important to remember about cooperative-MIMO schemes, in which it is not the case the the transmitter/receiver necessarily have multiple antennas, but a group of transmitters/receivers (with just one antenna each) form a cluster and they act as a MIMO system. All the variations are possible, i.e. SISO (trivial case), SIMO (a cluster of transmitting nodes sending to a single one), MISO (one single node sending to a cluster of nodes) or MIMO (a cluster of several nodes sending to another cluster of several nodes). An example of the usage of cooperative-MIMO is in wireless sensor networks (WSN). Due to the cooperative way these networks perform their activities, the usage of cooperative-MIMO is quite natural, improving communication range and helping in diminishing the overall network energy consumption.

Hi,

You can see The RF antenna diagram explanations here:

http://en.wikipedia.org/wiki/Single-input_single-output_system

SISO - 'Single Input, Single Output', the model more intuitive. As the name says, we have only one entry in the radio channel, and only one output;

MISO - 'Multiple Input, Single Output'. It is when the system has multiple inputs and a single output. In practice we have more than one antenna.

SIMO - 'Single Input, Multiple Output'. Works almost opposite to MISO.

MIMO - 'Multiple Input, Multiple Output': In practice we have multiple antennas at the transmitter and multiple antennas at the receiver.

Make it like this: Serial Input to Serial Output port, Serial Input to Parallel Output port, Parallel Input to Serial Output port and Parallel Input to Parallel Output port.

I hope the others had been answered here is 2 questions you asked about

SISO single input single output refers to a wireless communications system in which one antenna is used at the source transmitter, SIMO single input, and multiple output 2 antennas at the receiver

Let's discuss a single comm link, When you have multiple antennas at a terminal, you can use them in a variety of ways to improve performance: beamforming, spatial diversity, space-time coding, or spatial multiplexing. Spatial multiplexing is the breakthrough "trick" that greatly increases the spectral efficiency -- the number of bits/sec in a given bandwidth. If you have 4 Tx antennas, then you can send 4 independent data transmissions, and the channel capacity is roughly 4 times greater with MIMO spatial multiplexing than a SISO (one antenna) link with the same Tx power. You get this gain only when the radio channel is "rich scattering"-- meaning the signal bounces off many objects are arrives from many angles. Spatial multiplexing generally does not work in line-of-sight channels, like ground to air.

MIMO channels are modeled via an "H" matrix that gives the fading between all antenna pairs. The simplest way to model this matrix is with independent complex-Gaussian (unit variance) entries in the matrix. H= 1/sqrt(2) *(randn(N,M) + j* randn(N,M)).

SISO-single input single output

SIMO-single input multiple outputs

MISO-multiple inputs single output

MIMO-multiple inputs multiple outputs channels

for detail you can see the U-tube- http://www.youtube.com/watch?v=ZNfzBwIDcZY

hello,

See here advanced MIMO Dual RHCP LHCP animated Asynchronous transmission

http://www.hypercable.fr/index.php?option=com_content&view=article&id=51&Itemid=28&lang=fr

You have a limits the number the antennas you can use, four antenna perhaps is optimal , ,if we used channels coding you can improve your gain and if you used an Equaliser the gain you can get is limits

Sorry I forgott TX and RX explanations in connection with the MIMO antennas, you can see the full diagram in this 3 power point page PPT:

http://www.hypercable.fr/images/stories/wirake/MIMO_Rake__Antenna_concept_2.ppt

MIMO has inherent advantage of increased capacity as compared to SIMO and MISO counterpart. This is the case that MIMO is steadily becoming ubiquitous in all the forthcoming wireless communication systems in the form of Cooperative MIMO, Massive MIMO etc.

MIMO is better only when you have full rank channel matrix.

Choosing multiple antennas in any node will give advantage only when they are sufficiently apart. 

Pls go through a text book titled large MIMO systems or the famous text book by Dr Paulraj himself for clarity.

MIMO comes first in terms of better number of antennas, throughput and energy efficiency. It follows by MISO, then SIMO and lastly SISO