A user equipment (UE) monitors a Physical Downlink Control Channel (PDCCH) during a random access channel (PRACH) procedure. The UE receives a physical random access channel (PRACH) resource on a first sub-band of a component carrier (CC), wherein the CC is divided into a plurality of sub-bands and receives a Type1-PDCCH CSS (Physical Downlink Control Channel Common Search Space) set on a second sub-band of the CC, wherein the Type1-PDCCH CSS set corresponds to the PRACH resource.