The basic advantage of MIMO(Multiple Input Multiple Output) technology is that in the MIMO technology different data streams are transmitted simultaneously on the same frequency and time.
https://mytechnew2019.blogspot.com/2019/01/benefits-of-mimo-technology.html
Rank Indicator(RI) is an indicator which tells how well the multiple antenna works in the MIMO, i.e. the number of layers transmitted simultaneously on the same frequency and time.
Calculation of maximum RI:- Maximum RI is very close to number of antennas in Transmitting and receiving side. Suppose we have 2*2 MIMO( 2 Antennas in both transmitting and Receiving) then the value of RI are 1 and 2.
Note: If we have different number of transmitting and receiving antennas then the maximum RI is equal to one of less antennas.
How RI works:- Lets take an example of 2*2 MIMO. The possibilities of RI are 1 and 2.
The UE reports RI 2 when there is No Correlation(Interference) between both antennas i.e different data streams are being send by each TX(enhanced capacity).
The UE reports RI 1 when there is some interference between both antennas, i.e all the TX are sending same data streams(enhance coverage).
The feedback of RI by UE is based on the SINR value. For a UE to be able to support 2 layers (RI2) means that it has to be in a good SNR. The second thing in multipath rich environment, UEs prefer RI2 as it has embedded copies of the data streams. The third thing is the vendor's implementation. Some vendors switch on the basis of SINR only while other vendors switch on the basis of SINR plus FER while there are vendors that switch on the basis of SINR plus HARQ-Outs.
https://mytechnew2019.blogspot.com/2019/01/benefits-of-mimo-technology.html
Rank Indicator(RI) is an indicator which tells how well the multiple antenna works in the MIMO, i.e. the number of layers transmitted simultaneously on the same frequency and time.
Calculation of maximum RI:- Maximum RI is very close to number of antennas in Transmitting and receiving side. Suppose we have 2*2 MIMO( 2 Antennas in both transmitting and Receiving) then the value of RI are 1 and 2.
Note: If we have different number of transmitting and receiving antennas then the maximum RI is equal to one of less antennas.
How RI works:- Lets take an example of 2*2 MIMO. The possibilities of RI are 1 and 2.
The UE reports RI 2 when there is No Correlation(Interference) between both antennas i.e different data streams are being send by each TX(enhanced capacity).
The UE reports RI 1 when there is some interference between both antennas, i.e all the TX are sending same data streams(enhance coverage).
The feedback of RI by UE is based on the SINR value. For a UE to be able to support 2 layers (RI2) means that it has to be in a good SNR. The second thing in multipath rich environment, UEs prefer RI2 as it has embedded copies of the data streams. The third thing is the vendor's implementation. Some vendors switch on the basis of SINR only while other vendors switch on the basis of SINR plus FER while there are vendors that switch on the basis of SINR plus HARQ-Outs.
