Error for Predefined user position for txmode 3 and 4

Good afternoon
I’m trying to do several simulations with different groups of users in pre-defined positions. I am using MIMO 2X2 or MIMO 4X4 antenna configuration, in all the simulations
So I run simulations where I group different numbers of users per cell, for example:

  • First simulation: 1 user (position x1, y1, z1)
  • Second simulation: 2 users per cell (positions x1,y1,z1 and x2,y2,z2)
  • Third simulation: 4 users per cell (positions x1,y1,z1 - x2,y2, z2 - x3, y3,z3 and x4,y4,z4)

I am doing simulations where I add users to the cell, but the previous ones remain in the same position.I have seen that the best way to achieve it is with the predefined users option, where I can indicate the position of each one by using a matrix, in fact, the SLS detects the number of users from the position vector or matrix (predefinedUsers.positions).

For the two MIMO configurations, I have tested transmission modes 3 and 4 (Close Loop and Open Loop). When I try to simulate the Open Loop one, for two users or more, I get an error, which is attached below.
I have seen that this function always enters once more than the number of users selected, getting the error there, since it does not create the linkQualitymodel struct.

On the other hand, for the simulations with Close Loop, if I put three users or more, the results file only shows me the results of 3 users. I can share the .mat where you can find the number of users (8) and the results provided (3). I can even share the scenario file that I am using … (I can not attach these two files)

Do you know any more effective method than predefined user? In fact, for the poisson and gauss methods, the positions are different for each simulation. Is there any way using these two method to indicate the positions ?

Hi Alvaro,

As mentioned in our e-mail correspondence, you are currently using v1.2. Can you check whether the same issue occurs when you use the latest version (v1.3) in your setup?

Also, I assume that the problem only occurs when you set predefined positions for the users (and not when using other user placement schemes likes Poisson). Is this correct?


Hi Charmae.
Yes it was v1.2, could you provide me (by email) the link with the v1.3??
Regarding other user placement schemes, such as Poisson, Gaussian, there are no problems when simulating with different number of users…

Hi Álvaro,

Open Loop Spatial Multiplexing is not supported by the 5G System Level Simulator.

For the disappearing user issue, your region of interest is too small and your additional users are considered as interfering users and therefore do not show up in your results. If you want only positive x and y-values, you need to set the origin2D parameter to [500, 500] for a 1000 m span.


Hi all,
This week for me is complicated to check all of this in the new version (1.3), let me next week in order to set all the simulations in the new version (i will come back with the results).

Regarding Open loop transmission mode, what values could be set in the txmode.index parameter? and what is the meaning of each ?. I understand that txmode.index = 1 is SISO…
I didn’t find any explanation in the user manual neither in the feature list about the transmission modes, and i took the 2018 version of this simulator (v2.0 Q3), which included the OLSM mode. In fact, the list of features of the v2.0 Q3 was this one:
Transmission mode

  1. Single antenna
  2. Transmission Diversity (TxD)
  3. Open Loop Spatial Multiplexing (OLSM), Spatial Multiplexing with Cyclic Delay Diversity (CDD)
  4. Closed Loop Spatial Multiplexing (CLSM)
  5. Multiuser-MIMO
  6. Rank-1 CLSM
  7. Beamforming
  8. Eight Layer Spatial Multiplexing.

Dear Alvaro,

Version 1.3 of the 5G SLS supports Tx mode 1 (SISO) and 4 (MIMO CLSM). It does not support OLSM.

If I’m not mistaken, the Tx mode list that you specified is for the LTE-A downlink SLS, which is a different simulator (not a previous version of 5G SLS).


Ok, then, When I selected the tx mode 3 in my simulations in the 1.2 version (no SISO neither Close Loop), what tx mode is ???. And, is there any plan to include the support of the Open Loop transmission mode in the next version?

As an example of what I said about the problem regarding the simulations of CLSM for more than 3 users in pre-defined positions (SLS just simulates 3 users). In this picture, the simulation is configured for 5 users in a pre-defined position and the SLS just simulates the user number 1,3 and 5.

SEE IndexUserRoi
In the other hand, if i configure the simulation for 5 users with a gaussian distribution, the SLS simulates all users…
I can share the scenarios files, if needed