Terminal apparatus, base station apparatus, and communication method
A terminal apparatus includes: a receiver configured to receive an SS/PBCH block in an SS/PBCH block candidate; and a transmitter configured to transmit one random access preamble selected in a PRACH occasion. The terminal apparatus determines the PRACH occasion, based on a relationship between q SSB and the PRACH occasion. The q SSB is given by one of a remainder obtained by dividing t SSB by Q SSB or a remainder obtained by dividing d SSB by Q SSB . The t SSB is a timing index of the SS/PBCH block candidate. The d SSB indicates an index of a DMRS for a PBCH in the SS/PBCH block. The Q SSB indicates a number included in an MIB in the PBCH.
1. A terminal apparatus comprising:
reception circuitry configured to receive a first Synchronization Signal (SS)/Physical Broadcast Channel (PBCH) block corresponding to an index q SSB and receive a Radio Resource Control (RRC) message including a parameter Q SSB ; and
transmission circuitry configured to transmit a random access preamble in a Physical Random Access CHannel (PRACH) occasion, wherein
the transmission circuitry determines a relationship between the index q SSB and the PRACH occasion;
the index q SSB is equal to a remainder of an index d SSB divided by the parameter Q SSB ;
the index d SSB is an index of a Demodulation Reference Signal (DMRS) related to the PBCH included in the first SS/PBCH block;
the reception circuitry receives bitmap information of N SSB bits, n-th bit of the bitmap information indicates whether or not a second SS/PBCH block is transmitted in one or more SS/PBCH block candidates corresponding to the index q SSB =n−1; and
the relationship between the index q SSB and the PRACH occasion is determined based on the bitmap information.
2. The terminal apparatus according to claim 1 , wherein
of the bitmap information, bits from the parameter Q SSB +1 to N SSB is set to a prescribed value.
3. The terminal apparatus according to claim 1 , wherein
the parameter Q SSB is included in a Master Information Block (MIB), the bitmap information is included in System Information Block (SIB) 1.
4. A base station apparatus comprising:
transmission circuitry configured to transmit a first Synchronization Signal (SS)/Physical Broadcast Channel (PBCH) block corresponding to an index q SSB and transmit a Radio Resource Control (RRC) message Including a parameter Q SSB ; and
reception circuitry configured to receive a random access preamble in a Physical Random Access CHannel (PRACH) occasion, wherein
a relationship between the index q SSB and the PRACH occasion is determined, the index q SSB is equal to a remainder of an index d SSB divided by the parameter Q SSB ;
the index d SSB is an index of a Demodulation Reference Signal (DMRS) related to the PBCH included in the first SS/PBCH block;
the transmission circuitry transmits bitmap information of N SSB bits, n-th bit of the bitmap information indicates whether or not a second SS/PBCH block is transmitted in one or more SS/PBCH block candidates corresponding to the index q SSB =n−1; and
the relationship between the index q SSB and the PRACH occasion is determined based on the bitmap information.
5. The base station apparatus according to claim 4 , wherein
of the bitmat information, bits from the parameter Q SSB +1 to N SSB is set to a prescribed value.
6. The base station apparatus according to claim 4 , wherein
the parameter Q SSB is included in a Master Information Block (MIB), the bitmap information is included in System Information Block (SIB) 1.
7. A communication method used for a terminal apparatus, the communication method comprising:
receiving a first Synchronization Signal (SS)/Physical Broadcast Channel (PBCH) block corresponding to a index q SSB and receive a Radio Resource Control (RRC) message including a parameter Q SSB ;
transmitting a random access preamble in a Physical Random Access CHannel (PRACH) occasion; and
determining a relationship between the index q SSB and the PRACH occasion;
the index q SSB is equal to a remainder of an index d SSB divided by the parameter Q SSB ;
the index d SSB is an index of a Demodulation Reference Signal (DMRS) related to the PBCH included in the first SS/PBCH block;
the communication method further comprises receiving bitmap information of N SSB bits;
n-th bit of the bitmap information indicates whether or not a second SS/PBCH block is transmitted in one or more SS/PBCH block candidates corresponding to the index q SSB =n−1; and
the relationship between the index q SSB and the PRACH occasion is determined based on the bitmap information.