User equipments, base stations and methods

A base station apparatus comprising:

• transmitting circuitry configured to transmit a radio resource control (RRC) message including first information used for indicating an index of a downlink bandwidth part (DL BWP) in a primary cell,
• the transmitting circuitry configured to transmit another RRC message comprising second information used for indicating an index of an uplink bandwidth part (UL BWP) in the primary cell, and
• receiving circuitry configured to perform the random access procedure, wherein
• in a case that physical random access channel (PRACH) resources are not configured for an active UL BWP in the primary cell, the random access procedure is performed on a DL BWP being defined as index “0” in the primary cell and a UL BWP in the primary cell, and the random access procedure is not performed on the UL BWP unless the UL BWP is defined as index “0” and has a configured PRACH resource, and
• in a case that PRACH resources are configured for an active UL BWP in the primary cell, the random access procedure is performed on a DL BWP in the primary cell and the active UL BWP in the primary cell, the DL BWP being linked with the active UL BWP based on the index of the DL BWP indicated by using the first information and the index of the UL BWP indicated by using the second information.

A communication method of a user equipment comprising:

• receiving a radio resource control (RRC) message including first information used for indicating an index of a downlink bandwidth part (DL BWP) in a primary cell,
• receiving another RRC message comprising second information used for indicating an index of an uplink bandwidth part (UL BWP) in the primary cell, and
• performing, based on an initiation of a random access procedure, the random access procedure, wherein
• in a case that physical random access channel (PRACH) resources are not configured for an active UL BWP in the primary cell, the random access procedure is performed on a DL BWP being defined as index “0” in the primary cell and a UL BWP in the primary cell, and the random access procedure is not performed on the UL BWP unless the UL BWP is defined as index “0” and has a configured PRACH resource, and
• in a case that PRACH resources are configured for an active UL BWP in the primary cell, the random access procedure is performed on a DL BWP in the primary cell and the active UL BWP in the primary cell, the DL BWP being linked with the active UL BWP based on the index of the DL BWP indicated by using the first information and the index of the UL BWP indicated by using the second information.

A communication method of a base station apparatus comprising:

• transmitting a radio resource control (RRC) message including first information used for indicating an index of a downlink bandwidth part (DL BWP) in a primary cell,
• transmitting another RRC message comprising second information used for indicating an index of an uplink bandwidth part (UL BWP) in the primary cell, and
• performing the random access procedure, wherein
• in a case that physical random access channel (PRACH) resources are not configured for an active UL BWP in the primary cell, the random access procedure is performed on a DL BWP being defined as index “0” in the primary cell and a UL BWP in the primary cell, and the random access procedure is not performed on the UL BWP unless the UL BWP is defined as index “0” and has a configured PRACH resource, and
• in a case that PRACH resources are configured for an active UL BWP in the primary cell, the random access procedure is performed on a DL BWP in the primary cell and the active UL BWP in the primary cell, the DL BWP being linked with the active UL BWP based on the index of the DL BWP indicated by using the first information and the indicated index of the UL BWP indicated by using the second information.