Techniques for reference signal patterns
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive a first indication of a set of reference signal instances within a set of resources. The UE may receive a second indication of a resource element format of a reference signal instance of the set of reference signal instances, the resource element format including one or more null resource elements and one or more reference signal resource elements. The UE may additionally receive, from a base station, a reference signal for estimating carrier frequency offset (CFO) based on the first indication of the set of reference signal instances and the second indication of the resource element format of the reference signal instance. The UE may then communicate with the base station based on receiving the reference signal.
1. A user equipment (UE), comprising:
a transceiver,
at least one processor,
one or more memories coupled with the at least one processor; and
instructions stored in the one or more memories and operable, when executed by the at least one processor, to cause the UE to:
receive, via the transceiver, a first indication of a set of reference signal instances within a set of resources, wherein:
each reference signal instance of the set of reference signal instances is associated with an anchor resource element, and the first indication comprises a time density indicator associated with the set of reference signal instances, a frequency density indicator associated with the set of reference signal instances, a resource element offset indicator associated with the set of reference signal instances, a symbol offset indicator associated with the set of reference signal instances, or any combination thereof;
receive, via the transceiver, a first control message indicating a plurality of resource element formats, each resource element format of the plurality of resource element formats comprising one or more reference signal resource elements and one or more null resource elements that separate the one or more reference signal resource elements from other subcarriers in a frequency domain;
receive, via the transceiver, a second control message comprising a second indication of a resource element format of the plurality of resource element formats indicated by the first control message, the resource element format associated with a reference signal instance of the set of reference signal instances, the resource element format comprising the one or more null resource elements and the one or more reference signal resource elements;
receive, via the transceiver, a reference signal after receiving the first indication and the second indication, wherein a position of each reference signal instance within the set of resources is based at least in part on the anchor resource element associated with each reference signal instance, the time density indicator, the frequency density indicator, the resource element offset indicator, the symbol offset indicator, or any combination thereof;
perform one or more measurements associated with the received reference signal;
estimate a carrier frequency offset associated with the reference signal based at least in part on the one or more measurements; and
communicate, via the transceiver, with a network entity after receiving the reference signal, said communication being based at least in part on the estimated carrier frequency offset.
2. The UE of claim 1 , wherein the at least one processor is further configured to cause the UE to:
receive, via the transceiver, a control message comprising the first indication of the set of reference signal instances, the second indication of the resource element format of the reference signal instance, or both.
3. The UE of claim 1 , wherein the at least one processor is further configured to cause the UE to:
transmit, via the transceiver, a request for a pattern of a configuration for reference signals associated with estimating the carrier frequency offset, wherein receiving the first indication of the set of reference signal instances, the second indication of the resource element format of the reference signal instance, or both, occurs after transmitting the request.
4. The UE of claim 3 , wherein the at least one processor is further configured to cause the UE to:
communicate, via the transceiver, with the network entity in accordance with one or more parameters.
5. The UE of claim 4 , wherein the one or more parameters comprise a modulation and coding scheme, an expected carrier frequency offset, a block error rate, a frequency density associated with the set of resources, a time density associated with the set of resources, an allowable overhead of the set of resources which may be used for the set of reference signal instances, or any combination thereof.
6. The UE of claim 1 , wherein:
the time density indicator indicates a quantity of reference signal instances per symbol within the set of resources,
the frequency density indicator indicates a quantity of reference signal instances per resource block within the set of resources, and
the resource element offset indicator indicates a first offset in the frequency domain of the set of reference signal instances relative to a first boundary of the set of resources, or the symbol offset indicator indicates a second offset in a time domain of the set of reference signal instances relative to a second boundary of the set of resources.
7. The UE of claim 1 , wherein:
the reference signal instance comprises one or more reference signal resources elements and two or more null resource elements; and
a null resource element of the two or more null resource elements is positioned between the one or more reference signal resource elements and a resource element used for other information in the frequency domain.
8. The UE of claim 1 , wherein a first resource element format for resource elements within a first reference signal instance of the set of reference signal instances is different from a second resource element format for resource elements within a second reference signal instance of the set of reference signal instances.
9. The UE of claim 1 , wherein each reference signal instance is symmetrical in the frequency domain.
10. The UE of claim 1 , wherein:
the reference signal instance spans one resource element in a time domain and spans three or more resource elements in the frequency domain; and
the three or more resource elements in the frequency domain comprise three or more contiguous resource elements in the frequency domain.
11. The UE of claim 1 , wherein the one or more null resource elements of the reference signal instance comprise one or more empty subcarriers.
12. The UE of claim 1 , wherein the reference signal instance comprises a first reference signal resource element, a second reference signal resource element, and the one or more null resource elements positioned between the first reference signal resource element and the second reference signal resource element in the frequency domain.
13. The UE of claim 1 , wherein the reference signal instance comprises a first reference signal resource element and a second reference signal resource element adjacent to the first reference signal resource element in the frequency domain.
14. The UE of claim 1 , wherein the reference signal instance is positioned at a boundary of the set of resources and the one or more null resource elements of the reference signal instance are omitted from the reference signal instance.
15. The UE of claim 1 , wherein estimating the carrier frequency offset is based at least in part on the position of each reference signal instance within the set of resources.
16. The UE of claim 1 , wherein a power of the one or more reference signal resource elements within the set of reference signal instances is greater than a power of data elements within the set of resources, and wherein the reference signal for estimating the carrier frequency offset comprises a phase tracking reference signal.
17. A network entity, comprising:
a transceiver,
at least one processor,
one or more memories coupled with the at least one processor; and
instructions stored in the one or more memories and operable, when executed by the at least one processor, to cause the network entity to:
transmit, via the transceiver, a first indication of a set of reference signal instances within a set of resources, wherein:
each reference signal instance of the set of reference signal instances is associated with an anchor resource element, and the first indication comprises a time density indicator associated with the set of reference signal instances, a frequency density indicator associated with the set of reference signal instances, a resource element offset indicator associated with the set of reference signal instances, a symbol offset indicator associated with the set of reference signal instances, or any combination thereof;
transmit, via the transceiver, a first control message indicating a plurality of resource element formats, each resource element format of the plurality of resource element formats comprising one or more reference signal resource elements and one or more null resource elements that separate the one or more reference signal resource elements from other subcarriers in a frequency domain;
transmit, via the transceiver, a second control message comprising a second indication of a resource element format of the plurality of resource element formats indicated by the first control message, the resource element format associated with a reference signal instance of the set of reference signal instances, the resource element format comprising the one or more null resource elements and the one or more reference signal resource elements;
transmit, via the transceiver, a reference signal after receiving the first indication and the second indication, wherein a position of each reference signal instance within the set of resources is based at least in part on the anchor resource element associated with each reference signal instance, the time density indicator, the frequency density indicator, the resource element offset indicator, the symbol offset indicator, or any combination thereof; and
communicate with a user equipment (UE) based at least in part on transmitting the reference signal.
18. The network entity of claim 17 , wherein the at least one processor is further configured to cause the network entity to:
transmit, via the transceiver, a control message comprising the first indication of the set of reference signal instances, the second indication of the resource element format of the reference signal instance, or both.
19. The network entity of claim 17 , wherein the at least one processor is further configured to cause the network entity to:
receive, via the transceiver, a request for a pattern of a configuration for reference signals associated with estimating carrier frequency offset, wherein transmitting the first indication of the set of reference signal instances, the second indication of the resource element format of the reference signal instance, or both, occurs after receiving the request.
20. The network entity of claim 17 , wherein the first indication of the set of reference signal instances, the second indication of the resource element format, or both, is transmitted based at least in part on one or more parameters associated with communications between the UE and the network entity, wherein the one or more parameters comprise a modulation and coding scheme, an expected carrier frequency offset, a block error rate, a frequency density associated with the set of resources, a time density associated with the set of resources, an allowable overhead of the set of resources which may be used for the set of reference signal instances, or any combination thereof.
21. The network entity of claim 17 , wherein:
the time density indicator indicates a quantity of reference signal instances per symbol within the set of resources,
the frequency density indicator indicates a quantity of reference signal instances per resource block within the set of resources,
the resource element offset indicator indicates a first offset in the frequency domain of the set of reference signal instances relative to a first boundary of the set of resources, or
the symbol offset indicator indicates a second offset in a time domain of the set of reference signal instances relative to a second boundary of the set of resources.
22. The network entity of claim 17 , wherein:
the reference signal instance comprises one or more reference signal resources elements and two or more null resource elements; and
a null resource element of the two or more null resource elements positioned between the one or more reference signal resource elements and a resource element used for other information in the frequency domain.
23. A method for wireless communication at a user equipment (UE), the method comprising:
receiving a first indication of a set of reference signal instances within a set of resources, wherein:
each reference signal instance of the set of reference signal instances is associated with an anchor resource element, and the first indication comprises a time density indicator associated with the set of reference signal instances, a frequency density indicator associated with the set of reference signal instances, a resource element offset indicator associated with the set of reference signal instances, a symbol offset indicator associated with the set of reference signal instances, or any combination thereof;
receiving a first control message indicating a plurality of resource element formats, each resource element format of the plurality of resource element formats comprising one or more reference signal resource elements and one or more null resource elements that separate the one or more reference signal resource elements from other subcarriers in a frequency domain;
receiving a second control message comprising a second indication of a resource element format of the plurality of resource element formats indicated by the first control message, the resource element format associated with a reference signal instance of the set of reference signal instances, the resource element format comprising the one or more null resource elements and the one or more reference signal resource elements;
receiving a reference signal after receiving the first indication of the set of reference signal instances and the second indication of the resource element format of the reference signal instance, wherein a position of each reference signal instance within the set of resources is based at least in part on the anchor resource element associated with each reference signal instance, the time density indicator, the frequency density indicator, the resource element offset indicator, the symbol offset indicator, or any combination thereof;
performing one or more measurements associated with the received reference signal; and
estimating a carrier frequency offset associated with the reference signal based at least in part on the one or more measurements; and communicating with a network entity after receiving the reference signal, said communication being based at least in part on the estimated carrier frequency offset.
24. The method of claim 23 , further comprising:
transmitting a request for a pattern of a configuration for reference signals associated with estimating the carrier frequency offset, wherein receiving the first indication of the set of reference signal instances, the second indication of the resource element format of the reference signal instance, or both, is based at least in part on transmitting the request.
25. The method of claim 24 , further comprising:
communicating with the network entity in accordance with one or more parameters.
26. The method of claim 25 , wherein the one or more parameters comprise a modulation and coding scheme, an expected carrier frequency offset, a block error rate, a frequency density associated with the set of resources, a time density associated with the set of resources, an allowable overhead of the set of resources which may be used for the set of reference signal instances, or any combination thereof.
27. A method for wireless communication at a network entity, the method comprising:
transmitting a first indication of a set of reference signal instances within a set of resources, wherein:
each reference signal instance of the set of reference signal instances is associated with an anchor resource element, and the first indication comprises a time density indicator associated with the set of reference signal instances, a frequency density indicator associated with the set of reference signal instances, a resource element offset indicator associated with the set of reference signal instances, a symbol offset indicator associated with the set of reference signal instances, or any combination thereof;
transmitting a first control message indicating a plurality of resource element formats, each resource element format of the plurality of resource element formats comprising one or more reference signal resource elements and one or more null resource elements that separate the one or more reference signal resource elements from other subcarriers in a frequency domain;
transmitting a second control message comprising a second indication of a resource element format of the plurality of resource element formats indicated by the first control message, the resource element format associated with a reference signal instance of the set of reference signal instances, the resource element format comprising the one or more null resource elements and the one or more reference signal resource elements;
transmitting a reference signal after receiving the first indication of the set of reference signal instances and the second indication of the resource element format of the reference signal instance, wherein a position of each reference signal instance within the set of resources is based at least in part on the anchor resource element associated with each reference signal instance, the time density indicator, the frequency density indicator, the resource element offset indicator, the symbol offset indicator, or any combination thereof; and
communicating with a UE based at least in part on transmitting the reference signal.
28. The method of claim 27 , further comprising:
transmitting a control message comprising the first indication of the set of reference signal instances, the second indication of the resource element format of the reference signal instance, or both.
29. The method of claim 27 , further comprising:
receiving a request for a pattern of a configuration for reference signals associated with estimating carrier frequency offset, wherein transmitting the first indication of the set of reference signal instances, the second indication of the resource element format of the reference signal instance, or both, occurs after receiving the request.
30. The method of claim 27 , wherein the first indication of the set of reference signal instances, the second indication of the resource element format, or both, is transmitted based at least in part on one or more parameters associated with communications between the UE and the network entity, wherein the one or more parameters comprise a modulation and coding scheme, an expected carrier frequency offset, a block error rate, a frequency density associated with the set of resources, a time density associated with the set of resources, an allowable overhead of the set of resources which may be used for the set of reference signal instances, or any combination thereof.