The error message you got indicates that you computer had ran out of memory. If you can not switch to a computer with a larger memory, I would recommand the trying the following steps:
1. Change the parfor loop to a for loop
2. If you want to compare MRT and ZF but are not interested in the interference caused by the two BSs, I would recommand splitting the scenario into two scenarios. You would first simulate a scenria with one BS and 10 UE using the ZF multi-user MIMO mode and in the second scenario you change the transmission mode to MRT.
3. You can try reducing the total number of symbols per frame nSymbolsTotal.
4. If you are using FDD mode, you could deactivate the uplink and only simulate the downlink .
There are many ways in which you can reduce your scenario. You need to find out what you are interested in and then reduce your scenario according to that.