UL and DL cell based scheduler
The scheduling is performed on cell basis. The two main functions are to decide
which UE(s) shall be scheduled, the number of resources and the MCS to be applied. Furthermore the scheduler needs to be QoS aware. There is priority given to random access responses, control data, HARQ retransmissions.
The channel quality may be taken in consideration. In RL10 the DL exploits CQI reports to decide on frequency and time resources. In UL the scheduling decisions in RL10 are not based on quality but a random frequency allocation is deployed.
is carried out in steps.
First a determination of the free PRBs is done. PRBs needed for common channels like SIB, paging, and random access procedure have to be allocated.
Final allocation of UEs (bearers) onto PRB.
In a pre-scheduling step all UEs with data available for transmission based on the buffer fill levels are listed. Time domain scheduling: aparameter MAX-#_UE_DL decides how many UEs are allocated in the TTI being scheduled.
Frequency domain scheduling for candidate set 2 UEs: resource allocation in
frequency domain including number and location of allocated PRBs
Evaluation of the #PRBs that will be assigned to UEs. The max. # of UEs which can be scheduled per TTI time frame is restricted by an O&M parameter. RL T and RL10 limit the number to a max. of 10 UEs per TTI
A random function to assure equal distribution of PRBs over the available frequency range ( random frequency hopping) is used.