Resolving colliding signals
Systems and methods are disclosed herein that relate to transmitting and receiving a transmission when there is a collision between the transmission and reserved resource elements. In some embodiments, a radio access node for a cellular communications network is disclosed, wherein the radio access node comprises a transceiver, a processor, and memory storing instructions executable by the processor whereby the radio access node is operable to transmit, via the transceiver, a downlink transmission to a wireless device using one or more Physical Resource Blocks (PRBs) that comprise reserved Resource Elements (REs) by puncturing the downlink transmission at positions of the reserved REs. In some embodiments, the downlink transmission is an Enhanced Physical Downlink Control Channel (EPDCCH) transmission or a Physical Downlink Shared Channel (PDSCH) transmission. Further, in some embodiments, the reserved REs are REs utilized for one or more CSI-RSs.
1. A user equipment operable in a cellular communications network, the user equipment comprising:
a transceiver;
a processor in communication with the transceiver; and
memory storing instructions executable by the processor to cause the user equipment is operable to:
receive a physical downlink transmission from a base station on one or more Physical Resource Blocks (PRBs) assuming by the user equipment that the physical downlink transmission is first mapped to Resource Elements (REs) in one or more PRBs and then reference symbols are mapped to a subset of the REs in the one or more PRBs that are reserved REs such that the downlink transmission is punctured by the reference symbols at positions of the reserved REs.
2. The user equipment of claim 1 , wherein the user equipment is further operable to increase the number of aggregated enhanced Control Channel Elements (eCCEs).
3. The user equipment of claim 1 , wherein receiving the physical downlink transmission comprises receiving the physical downlink transmission at a reduced code rate when the physical downlink transmission is punctured by the reference symbols at positions of the reserved REs.
4. The user equipment of claim 1 , wherein the physical downlink channel transmission is a Physical Downlink Shared Channel (PDSCH) transmission.
5. The user equipment of claim 4 , wherein the reference symbols are Channel State Information Reference Signal (CSI-RS) reference symbols.
6. The user equipment of claim 1 , wherein the physical downlink channel transmission is an Enhanced Physical Downlink Control Channel (EPDCCH) transmission.
7. The user equipment of claim 6 , wherein the reference symbols are Channel State Information Reference Signal (CSI-RS) reference symbols.
8. A user equipment operable in a cellular communications network, the wireless
device comprising:
a transceiver;
a processor in communication with the transceiver; and
memory storing instructions executable by the processor to cause the user equipment to:
receive a message with an indicator of reserved Resource Elements (REs) presence in a subframe in which a physical downlink channel transmission is transmitted from a base station to the user equipment;
determine reserved REs presence in the subframe based on the indicator;
upon determining that reserved REs are present in the subframe, attempt reception of the physical downlink channel transmission based on an assumption that reserved REs are present in the subframe; and
upon determining that reserved REs are not present in the subframe, attempt reception of the physical downlink channel transmission based on an assumption that reserved REs are not present in the subframe.
9. The user equipment of claim 8 , wherein the indicator comprises time-domain information regarding the presence of reserved REs.
10. The user equipment of claim 8 , wherein the indicator comprises information that indicates which REs are reserved REs.
11. The user equipment of claim 8 , wherein the physical downlink channel transmission is an Enhanced Physical Downlink Control Channel (EPDCCH) transmission.
12. The user equipment of claim 8 , wherein the reserved REs are REs utilized for one or more Channel State Information Reference Signals (CSI-RSs).
13. The user equipment of claim 8 , wherein the physical downlink channel transmission is a Physical Downlink Shared Channel (PDSCH) transmission.
14. The user equipment of claim 13 , wherein the reserved REs are REs utilized for one or more Channel State Information Reference Signals (CSI-RSs).
15. A base station operable in a cellular communications network, the base station comprising:
a transceiver;
a processor in communication with the transceiver; and
memory storing instructions executable by the processor to cause the base station to perform operations comprising:
transmitting a physical downlink transmission to a user equipment using one or more Physical Resource Blocks (PRBs) that comprise reserved Resource Elements (REs) by first mapping the physical downlink transmission to REs in the one or more PRBs and then mapping reference symbols to a subset of the REs in the one or more PRBs that are the reserved REs such that the physical downlink transmission is punctured by the reference symbols at positions of the reserved REs.
16. The base station of claim 15 , wherein transmitting the downlink transmission comprises transmitting the downlink transmission at a reduced code rate when the downlink transmission is punctured by the reference symbols at positions of the reserved REs.
17. The base station of claim 15 , wherein the physical downlink channel transmission is a Physical Downlink Shared Channel (PDSCH) transmission.
18. The base station of claim 17 , wherein the reference symbols are Channel State Information Reference Signal (CSI-RS) reference symbols.
19. The base station of claim 15 , wherein the physical downlink channel transmission is an Enhanced Physical Downlink Control Channel (EPDCCH) transmission.