Method and apparatus for indicating center frequency offset for narrowband UE in wireless communication system
A method and apparatus for receiving a downlink (DL) transmission in a wireless communication system is provided. A narrowband user equipment (NB UE) receives an offset between a center frequency of a system bandwidth and a center frequency of a narrowband from a network, and receives the DL transmission from the network based on the offset.
1. A method performed by a narrowband internet of things (NB-IoT) user equipment (UE) in a wireless communication system, the method comprising:
receiving, from a network, information on NB-IoT region, wherein the information on NB-IoT region includes an offset between a center frequency of a system bandwidth and a center frequency of a narrowband, and the information on NB-IoT region includes size of guard bands;
receiving, from the network, a notification notifying that data is transmitted on the guard bands;
upon receiving the notification, monitoring the guard bands; and
receiving a physical broadcast channel (PBCH) for the NB-IoT, a primary synchronization signal (PSS) for the NB-IoT and a secondary synchronization signal (SSS) for the NB-IoT from the network on only one of the guard bands based on the size of the guard bands,
wherein the guard bands are defined in both edges of the system bandwidth.
2. The method of claim 1 , wherein a location of at least one of the PBCH, PSS or SSS for the NB-IoT is not fixed for the center frequency of the system bandwidth.
3. The method of claim 1 , wherein the DL transmission is related to a physical downlink control channel (PDCCH) for the NB-IoT or a physical downlink shared channel (PDSCH) for the NB-IoT.
4. The method of claim 3 , wherein a legacy cell-specific reference signal (CRS) is used for the PDCCH for the NB-IoT or the PDSCH for the NB-IoT.
5. The method of claim 4 , wherein scrambling of the legacy CRS changes based on a location of the narrowband.
6. The method of claim 1 , wherein receiving the DL transmission comprises receiving a narrowband reference signal (NB-RS) in a subframe.
7. The method of claim 6 , wherein the subframe in which the NB-RS is received carries at least one of a narrowband physical broadcast channel (NB-PBCH), a narrowband system information block (NB-SIB), or a narrowband paging.
8. A narrowband internet of things (NB-IoT) user equipment (UE) in a wireless communication system, the NB UE comprising:
a memory;
a transceiver; and
a processor, coupled to the memory and the transceiver, that:
controls the transceiver to receive, from a network, information on NB-IoT region, wherein the information on NB-IoT region includes an offset between a center frequency of a system bandwidth and a center frequency of a narrowband, and the information on NB-IoT region includes size of guard bands,
controls the transceiver to receive, from the network, a notification notifying that data is transmitted on the guard bands,
upon receiving the notification, monitor the guard bands; and
controls the transceiver to receive a physical broadcast channel (PBCH) for the NB-IoT, a primary synchronization signal (PSS) for the NB-IoT and a secondary synchronization signal (SSS) for the NB-IoT from the network only on one of the guard bands based on the size of the guard bands,
wherein the guard bands are defined in both edges of the system bandwidth.
9. The UE of claim 8 , wherein a location of at least one of the PBCH, PSS or SSS for the NB-IoT is not fixed for the center frequency of the system bandwidth.
10. The UE of claim 8 , wherein the DL transmission is related to a physical downlink control channel (PDCCH) for the NB-IoT or a physical downlink shared channel (PDSCH) for the NB-IoT.
11. The UE of claim 10 , wherein a legacy cell-specific reference signal (CRS) is used for the PDCCH for the NB-IoT or the PDSCH for the NB-IoT.
12. The UE of claim 11 , wherein scrambling of the legacy CRS changes based on a location of the narrowband.