What type of load balancing you are looking ? Are you looking for SGW load balancing ? PUSCH and PDSCH physical channels being used for data plane in uplink and downlink respectively. EnodeB MAC downlink scheduler is responsible to schedule data for set of users per millisecond level of granularity in downlink and EnodeB MAC uplink scheduler is responsible to allocated resources in uplink. At the eNodeB, UE's can be categorized into two groups if eNodeB is running in hybrid mode.
Downlink/Uplink scheduler might use priority of bearer's to schedule UE's data. It is upto eNodeB vendor how they want to implement. I know "Round Robin" and "PFS algorithm" being used by eNodeB scheduler.