What is the meaning to achieve full diversity?

[yelvis]

meaning of diversity

Hi all,

I am sorry for my simple question. however I guess some professionals can know my asking easily.

While reading paper, I wonder that what is full diversity?

Related to that, Is it good thing that degree of freedom is large?

 

[umery2k75]

full diversity

Full diversity in sense for what?

 

[yelvis]

diversity meaning

Full diversity in sense for what?

Hi.

Thanks for attention.

I am interested in getting "diversity gain" in wireless system. In there, I heard the received signal can be interpreted by "degree of freedom"-I guess it is the number of dimension for orthogonal set- and good system should achieve full diversity.

In the sense of geometry, I think small degree of freedom is better since we can analyse a vector with small number of dimensions. Is it right?
and, full diversity would mean that combined signal have full diversity factors...right?

 

[umery2k75]

what is the meaning of diversity

If we use multiple independent channels on which same information is transmitted at a same time, then we creating additional spatial degree of freedom that improves the signal strength and will have good coverage,etc. With diversity we improve the reliablity of the signal.

A single word gain cannot simply be used to describe the improvement of the system either in the sense of full diversity or full degree of freedom, there are so many other parameter. There can be a tradeoff between two sets of variable. One could have a good coverage, but might have low bandwidth of signal. Other could have a low coverage, but might have high bandwidth of signal.There is a tradeoff between error probability and transmission rate.Signal to Noise Ratio(SNR) always come into play with wireless systems.Diversity and Multiplexing gain are inversly proportional to each other. With increase of diversity there are is decrease in multiplexing gain. So again, we have a tradeoff. It depends what sets of parameter suits the best in a system. It's like you are keeping one value at extreme that is achieving full diversity. So multiplexing gain is going to be at the least possible value.

 

[yelvis]

meaning of diversity

Thanks a lot!!

I understand what you mean. However, I wanna know the exact concept of "full" diversity and "degree of freedom for diversity".

degree of freedom for diversity = full diversity?

Degree of freedom is used frequently in signal analysis. I think, for example, In BPSK modulation, the degree of freedom of BPSK signal is 1. Then, if we use two tx antenna, the degree of freedom of BPSK signal would be increased?
If yes, the increasing of the dimension of the signal is good thing?

If we use multiple independent channels on which same information is transmitted at a same time, then we creating additional spatial degree of freedom that improves the signal strength and will have good coverage,etc. With diversity we improve the reliablity of the signal.

A single word gain cannot simply be used to describe the improvement of the system either in the sense of full diversity or full degree of freedom, there are so many other parameter. There can be a tradeoff between two sets of variable. One could have a good coverage, but might have low bandwidth of signal. Other could have a low coverage, but might have high bandwidth of signal.There is a tradeoff between error probability and transmission rate.Signal to Noise Ratio(SNR) always come into play with wireless systems.Diversity and Multiplexing gain are inversly proportional to each other. With increase of diversity there are is decrease in multiplexing gain. So again, we have a tradeoff. It depends what sets of parameter suits the best in a system. It's like you are keeping one value at extreme that is achieving full diversity. So multiplexing gain is going to be at the least possible value.

 

[Etsh]

what is the meaning of achieve in simple

full diversity means that when u use Mt transmitter antenna and Mr receiver antenna the probability of error increase exponential to Mr or Mt or both depends on schemes

so if it depend on Mt*Mr so the technique provide full diversity this is optimal case of course in MIMo system

and i think that degree if freedom is Mt*Mr in case MIMO systems

 

[itengineer79]

achieve meaning and value

Hello Friends..
I was think that full diversity its mean:
That every antenna should transmit all symbols in the block ..
i.e
If we have two Tx and Two Rx , and 4 symbols to transmit s1 s2 s3 s4 ..
we said the system is full diversity when
Tx1 transmit s1 s2 s3 s4 and same for Tx2 with different times....
As I think ......
Please reright if its wrong.

Regards