LTE System Toolbox on Matlab is a very powerful tool that support many of 5G related technologies and allow you to develop your specific algorithms and techniques. moreover it allows you to integrate with SDR hardware peripherals such as USRPs.
There are also LABVIEW LTE Application Framework from NI and can be also integrated with USRPs. But LTE System Toolbox on Matlab is more powerfull.
You can also check for openairinterface: http://www.openairinterface.org/