Terminal device, base station device, and communication method for performing random access procedure
A terminal apparatus performs a random access procedure; and receives a physical channel, in which the random access procedure includes a 2 step contention based random access procedure, a 4 step contention based random access procedure, and a non-contention based random access procedure, and the physical channel indicates an initiation of any of the 4 step contention based random access procedure and the non-contention based random access procedure.
1. A terminal device comprising:
reception circuitry configured to:
receive system information including random-access information and a Reference Signal Received Power (RSRP) threshold for a 2-step contention based random-access procedure, and
receive an indication for handover from a first cell; and
higher layer processing circuitry configured to initiate, based on information included in the indication for handover, one of the 2-step contention based random-access procedure, a 4-step contention based random-access procedure, and a non-contention based random-access procedure, wherein:
the non-contention based random-access procedure is initiated on a second cell based on an allocation of a random-access resource in a case that the indication for handover includes the allocation of the random-access resource;
the 4-step contention based random-access procedure is initiated on the second cell based on the random-access information included in the received system information in a case that the indication for handover does not include the allocation of the random-access resource and a cell-level RSRP of a downlink reference signal of the second cell is not above the RSRP threshold included in the received system information, the cell-level RSRP being measured by the terminal device; and
the 2-step contention based random-access procedure is initiated on the second cell based on the random-access information included in the received system information in a case that the indication for handover does not include the allocation of the random-access resource and the cell-level RSRP is above the RSRP threshold included in the received system information.
2. A base station device comprising:
transmission circuitry configured to transmit system information including random-access information and a Reference Signal Received Power (RSRP) threshold for a 2-step contention based random-access procedure, and
transmit an indication for handover via a first cell; and
higher layer processing circuitry configured to:
indicate, to a terminal device, to initiate a non-contention based random-access procedure on a second cell by including an allocation of a random-access resource in the indication for handover, and
indicate, to the terminal device, to initiate one of a 4-step contention based random-access procedure and the 2-step contention based random-access procedure by not including the allocation of the random-access resource in the indication for handover, wherein:
the 4-step contention based random-access procedure is initiated on the second cell based on the random-access information included in the transmitted system information in a case that the indication for handover does not include the allocation of the random-access resource and a cell-level RSRP of a downlink reference signal of the second cell is not above the RSRP threshold included in the transmitted system information, the cell-level RSRP being measured by the terminal device; and
the 2-step contention based random-access procedure is initiated on the second cell based on the random-access information included in the transmitted system information in a case that the indication for handover does not include the allocation of the random-access resource and the cell-level RSRP is above the RSRP threshold included in the transmitted system information.
3. A communication method performed by a terminal device, the communication method comprising:
receiving system information including random-access information and a Reference Signal Received Power (RSRP) threshold for a 2-step contention based random-access procedure;
receiving an indication for handover from a first cell; and
initiating, based on information included in the indication for handover, one of the 2-step contention based random-access procedure, a 4-step contention based random-access procedure, and a non-contention based random-access procedure, wherein:
the non-contention based random-access procedure is initiated on a second cell based on an allocation of a random-access resource in a case that the indication for handover includes the allocation of the random-access resource;
the 4-step contention based random-access procedure is initiated on the second cell based on the random-access information included in the received system information in a case that the indication for handover does not include the allocation of the random-access resource and a cell-level RSRP of a downlink reference signal of the second cell is not above the RSRP threshold included in the received system information, the cell-level RSRP being measured by the terminal device; and
the 2-step contention based random-access procedure is initiated on the second cell based on the random-access information included in the received system information in a case that the indication for handover does not include the allocation of the random-access resource and the cell-level RSRP is above the RSRP threshold included in the received system information.
4. A communication method performed by a base station device, the communication method comprising:
transmitting system information including random-access information and a Reference Signal Received Power (RSRP) threshold for a 2-step contention based random-access procedure;
transmitting an indication for handover via a first cell;
indicating, to a terminal device, to initiate a non-contention based random-access procedure on a second cell by including an allocation of a random-access resource in the indication for handover; and
indicating, to the terminal device, to initiate one of a 4-step contention based random-access procedure and the 2-step contention based random-access procedure by not including the allocation of the random-access resource in the indication for handover, wherein:
the 4-step contention based random-access procedure is initiated on the second cell based on the random-access information included in the transmitted system information in a case that the indication for handover does not include the allocation of the random-access resource and a cell-level RSRP of a downlink reference signal of the second cell is not above the RSRP threshold included in the transmitted system information, the cell-level RSRP being measured by the terminal device; and
the 2-step contention based random-access procedure is initiated on the second cell based on the random-access information included in the transmitted system information in a case that the indication for handover does not include the allocation of the random-access resource and the cell-level RSRP is above the RSRP threshold included in the transmitted system information.