MIMO in LTE

[forumuser-2008]

Hello,

I have two questions regarding to MIMO in LTE:

1. If I use 1T1R SISO system and TM3 is configured: can I see only Open Loop Transmit Diversity or is it possible to see Open Loop Spatial Multiplexing?

2. Could someone explain in easy way the difference between Logical Antenna Ports and Physical Antenna Ports?


Thanks in advance for your feedback

[T_ADD]

Hi TM3 is open loop with spatial multiplexing. No other. Google R&S beamforming and TM modes pdf.

[Nyquist]

@forumuser-2008, have a look at this.
Good reading.
Nyquist

[forumuser-2008]

Hi TM3 is open loop with spatial multiplexing. No other. Google R&S beamforming and TM modes pdf.


Thanks, I mentioned 1. If I use 1T1R SISO system and TM3 is configured: can I see only Open Loop Transmit Diversity or is it possible to see Open Loop Spatial Multiplexing?


Is it possible again???

[Nyquist]

@forumuser-2008. Regarding your question 2) I don't know too much but I think that physical antenna port, as its name indicates, is the physical connector of one antenna. Normally mobile systems have two physical ports to be configured each as TX, RX or TX/RX. One modern technology antenna could have internally more than 2 antennas, I would say 32, 64,..., and the use of a antenna port multiplexing should be required. I understand that each internal logical antenna has one logical antenna port. From my point of view, one modern antenna with 32 logical antennas has 32 logical antenna ports but only two physical port. May anyone confirm what I am trying to explain?
Regarding your question 1), TM3 requires 2 or 4 antennas. If you have 1TX1RX you only have one antenna, so these are not compatible. But if you mean that you have two antennas configured as 1TX1RX each one, you could configured any transmission mode requiring more than one antenna (all except TM1 and TM7, according table 3 from document I sent you above).
I am not expert on antenna systems and I have being waiting for some expert answer to your questions, and this is only my view.
Hope it helps.
Nyquist

[marcengo]

1) For TM3 you need 2x2 at least.

[jbada]

Hi

It is not possible to configure TM3 with 1T1R. In this case the solution is to use TM1.

[linhhy]

hope it help,

1. If I use 1T1R SISO system and TM3 is configured: can I see only Open Loop Transmit Diversity or is it possible to see Open Loop Spatial Multiplexing?

--> No way to get Open Loop Spatial Multiplexing with 1T1R. It's typical for old DAS system.

2. Could someone explain in easy way the difference between Logical Antenna Ports and Physical Antenna Ports?

--> Physical is physical :-). Logical port, can say it's agreement between UE and eNodeB. It consists a set of things (time, frequency, physical antenna) those UE and eNode know to recognize one configuration.


Hello,

I have two questions regarding to MIMO in LTE:

1. If I use 1T1R SISO system and TM3 is configured: can I see only Open Loop Transmit Diversity or is it possible to see Open Loop Spatial Multiplexing?


2. Could someone explain in easy way the difference between Logical Antenna Ports and Physical Antenna Ports?


Thanks in advance for your feedback

[forumuser-2008]

hope it help,

1. If I use 1T1R SISO system and TM3 is configured: can I see only Open Loop Transmit Diversity or is it possible to see Open Loop Spatial Multiplexing?

--> No way to get Open Loop Spatial Multiplexing with 1T1R. It's typical for old DAS system.

2. Could someone explain in easy way the difference between Logical Antenna Ports and Physical Antenna Ports?

--> Physical is physical :-). Logical port, can say it's agreement between UE and eNodeB. It consists a set of things (time, frequency, physical antenna) those UE and eNode know to recognize one configuration.

Thanks, a lot.

But 2nd explanation is not so clear :)

[linhhy]

Thanks, a lot.

But 2nd explanation is not so clear :)

An antenna port is defined by its associated Reference Signal. It indicates physical layer specification.
Antenna port 0,1,2,3 indicate actual physical antenna port. The other ports are logical port, i.e for some purposes. E.g port 4 for MBMS RS, port 5 for UE-specific RS,... These will be mapped on physical port, which both UE and eNode know.