Hi Galini,
The LTE System Toolbox uses a MATLAB multi-dimensional array to represent a subframe resource grid across a set of antenna ports.
The mwltelibrary mex function is often used to create the resource element indices associated with a given LTE physical channel or signal but it doesn't create the subframe grid itself. This is done using MATLAB code which assigns the physical channel/signal symbols into the grid locations associated with that particular channel, i.e.
subframegrid(channelindices) = channelsymbols
In the toolbox, the entire subframe grid is built up by successive calls to map the transmission symbols to the grid locations associated with all the various channels/signals (shared,control,sync,RS etc).
There is more information about the grid indexing mechanism in the Getting Started with LTE System Toolbox section of the toolbox examples.
The same pattern is used in the MATLAB code in the toolbox link waveform generators, lteRMCDLTool and lteRMCULTool.
If you want to create a variant of an LTE subframe grid, then, if using the same pattern, you will need to create new index generators which follow your required layout. You could start by modifying the above example.
Graham
