Method for transmitting and receiving synchronization signal block and apparatus therefor
Disclosed is a method for a terminal to receive a synchronization signal block (SSB) in a wireless communication system. In particular, the method comprises receiving, on a first half frame or a second half frame included in a wireless frame, at least one SSB mapped to a plurality of symbols, wherein the at least one SSB is any one of a first SSB received on the first half frame and a second SSB received on the second half frame, and a signal of the same type is mapped to a first symbol included in a plurality of symbols to which the first SSB is mapped and a second symbol included in a plurality of symbols to which the second SSB is mapped, but a phase of the first symbol and a phase of the second symbol are different.
1. A method of receiving a synchronization signal block (SSB) by a user equipment (UE) in a wireless communication system, the method comprising:
receiving at least one SSB in a first half-frame or a second half-frame,
wherein the first half-frame and the second half-frame are included in a radio frame,
wherein the at least one SSB is one of a first SSB including a first Physical Broadcast Channel (PBCH) received in the first half-frame or a second SSB including a second PBCH received in the second half-frame,
wherein the first PBCH is mapped to a first symbol included in first symbols to which the first SSB is mapped and a second symbol included in second symbols to which the second SSB is mapped,
wherein phases of the first symbol and the second symbol are different,
wherein a first demodulation reference signal (DMRS) is mapped to the first symbol and a second DMRS is mapped to the second symbol,
wherein, based on the UE receiving the at least one SSB in a first frequency band equal to or lower than 6 GHz, a first transmission power of the first DMRS and the second DMRS is higher than a second transmission power of the first PBCH and the second PBCH, and
wherein, based on the UE receiving the at least one SSB in a second frequency band higher than 6 Ghz, the first transmission power and the second transmission power are identical.
2. The method of claim 1 ,
wherein the phases of the first symbol and the second symbol have a difference of 180 degrees.
3. The method of claim 1 ,
wherein the first PBCH and the second PBCH include an indicator for distinguishing between the first half-frame and the second half-frame, and
the indicator is used for generating a scrambling sequence of the PBCH.
4. The method of claim 3 ,
wherein sequences of the first DMRS and the second DMRS are generated based on (i) a number of SSB indexes obtainable through the first DMRS and the second DMRS and (ii) the indicator.
5. The method of claim 4 ,
wherein the sequences are generated based on multiplication of the number of the SSB indexes and a value indicated by the indicator.
6. The method of claim 1 ,
wherein, based on detection of the first SSB, the UE performs detection of the second SSB in a specific time duration after a predetermined time from a timing at which the first SSB is detected.
7. The method of claim 1 , wherein a first sequence of the first DMRS is different from a second sequence of the second DMRS.
8. The method of claim 1 , wherein a first frequency position to which the first DMRS is different from a second frequency position to which the second DMRS.
9. The method of claim 1 ,
wherein, based on initial access performed by the UE, the at least one SSB is repeatedly transmitted at a first time periodicity, and
based on radio resource control (RRC) connection state of the UE, the at least one SSB is repeatedly transmitted at a second time periodicity longer than the first time periodicity.
10. The method of claim 1 ,
wherein, based on assumption that signals transmitted from a serving cell and a neighbor cell of the UE are received within a predetermined error range, time information obtained through an SSB received from the serving cell is equally applied to an SSB received from the neighbor cell.
11. A user equipment (UE) for receiving a synchronization signal block (SSB) in a wireless communication system, the UE comprising:
a transceiver configured to transmit and receive a signal to and from a base station (BS); and
a processor connected to the transceiver and configured to control the transceiver to receive at least one SSB in a first half-frame or a second half-frame,
wherein the first half-frame and the second half-frame are included in a radio frame,
wherein the at least one SSB is one of a first SSB including a first Physical Broadcast Channel (PBCH) received in the first half-frame or a second SSB including a second PBCH received in the second half-frame,
wherein the first PBCH is mapped to a first symbol included in first symbols to which the first SSB is mapped and a second symbol included in second symbols to which the second SSB is mapped,
wherein phases of the first symbol and the second symbol are different,
wherein a first demodulation reference signal (DMRS) is mapped to the first symbol and a second DMRS is mapped to the second symbol,
wherein, based on the UE receiving the at least one SSB in a first frequency band equal to or lower than 6 GHz, a first transmission power of the first DMRS and the second DMRS is higher than a second transmission power of the first PBCH and the second PBCH, and
wherein, based on the UE receiving the at least one SSB in a second frequency band higher than 6 Ghz, the first transmission power and the second transmission power are identical.
12. A method of transmitting a synchronization signal block (SSB) by a base station (BS) in a wireless communication system, the method comprising:
transmitting at least one SSB in a first half-frame or a second half-frame,
wherein the first half-frame and the second half-frame are included in a radio frame,
wherein the at least one SSB is one of a first SSB including a first Physical Broadcast Channel (PBCH) transmitted in the first half-frame or a second SSB including a second PBCH transmitted in the second half-frame,
wherein the first PBCH is mapped to a first symbol included in first symbols to which the first SSB is mapped and a second symbol included in second symbols to which the second SSB is mapped,
wherein phases of the first symbol and the second symbol are differently mapped,
wherein a first demodulation reference signal (DMRS) is mapped to the first symbol and a second DMRS is mapped to the second symbol,
wherein, based on the UE receiving the at least one SSB in a first frequency band equal to or lower than 6 GHz, a first transmission power of the first DMRS and the second DMRS is higher than a second transmission power of the first PBCH and the second PBCH, and
wherein, based on the UE receiving the at least one SSB in a second frequency band higher than 6 Ghz, the first transmission power and the second transmission power are identical.
13. A base station (BS) for transmitting a synchronization signal block (SSB) in a wireless communication system, the BS comprising:
a transceiver configured to transmit and receive a radio signal to and from a user equipment (UE); and
a processor connected to the transceiver and configured to transmit the at least one SSB in a first half-frame or a second half-frame,
wherein the first half-frame and the second half-frame are included in a radio frame,
wherein the at least one SSB is one of a first SSB including a first Physical Broadcast Channel (PBCH) transmitted in the first half-frame or a second SSB including a second PBCH transmitted in the second half-frame,
wherein the first PBCH is mapped to a first symbol included in first symbols to which the first SSB is mapped and a second symbol included in second symbols to which the second SSB is mapped,
wherein phases of the first symbol and the second symbol are differently mapped,
wherein a first demodulation reference signal (DMRS) is mapped to the first symbol and a second DMRS is mapped to the second symbol,
wherein, based on the UE receiving the at least one SSB in a first frequency band equal to or lower than 6 GHz, a first transmission power of the first DMRS and the second DMRS is higher than a second transmission power of the first PBCH and the second PBCH, and
wherein, based on the UE receiving the at least one SSB in a second frequency band higher than 6 Ghz, the first transmission power and the second transmission power are identical.