Hello Gupta,
I_REFERENCE_DATE is used for based on which time-dependent values will be assessed.
Check in your cube whether you have time dependent data.
Refer to the point 7 in the below link.
http://help.sap.com/saphelp_nw70/helpdata/EN/80/1a6791e07211d2acb80000e829fbfe/content.htm
Regards,
Thanga