Efficient MAC CE indication of spatial relation for semi-persistent SRS
Systems and methods for Semi-Persistent Sounding Reference Signal (SP SRS) resource activation or deactivation are disclosed. In some embodiments, a method of operation of a wireless device in a cellular communications network comprises receiving, from a network node, a Medium Access Control (MAC) Control Element (CE). The MAC CE comprises an indication of a SP SRS resource set to be activated or deactivated and information that indicates a spatial relation for the SP SRS resource set to be activated or deactivated. In this manner, a MAC CE for SP SRS resource set activation or deactivation is provided in a manner that gives spatial relation information in an efficient and flexible manner.
1. A method of operation of a wireless device in a cellular communications network, comprising:
receiving, from a network node, a Medium Access Control, MAC, Control Element, CE, comprising:
an indication of a semi-persistent sounding reference signal resource set to be activated or deactivated; and
information that indicates a spatial relation for the semi-persistent sounding reference signal resource set to be activated or deactivated;
wherein the MAC CE comprises:
a first octet that comprises the indication of the semi-persistent sounding reference signal resource set to be activated or deactivated;
a second octet that comprises an indication of a type of reference signal for which the spatial relation is provided and an identifier of a reference signal resource set for the type of reference signal for which the spatial relation is provided;
when the indication of the type of reference signal is set to “1”, the identifier of the reference signal resource set comprises a Channel State Information Reference Signal, CSI-RS, resource index; and
when the indication of the type of reference signal is set to “0”, the identifier of the reference signal resource set comprises one or more of: Synchronization Signal Block, SSB, index; and Sounding Reference Signal, SRS, resource index.
2. The method of claim 1 wherein the indication of the type of reference signal comprises two bits that indicate the type of reference signal, wherein:
a first state of the two bits indicates that the type of reference signal is a first type of reference signal;
a second state of the two bits indicates that the type of reference signal is a second type of reference signal; and
a third state of the two bits indicates that the type of reference signal is a third type of reference signal.
3. The method of claim 2 wherein the first type of reference signal is a CSI-RS the second type of reference signal is a SSB and the third type of reference signal is a SRS.
4. The method of claim 1 wherein:
if a first bit in the second octet is set to a first state:
the first bit serves as the indication of the type of reference signal for which the spatial relation is provided and the type of reference signal for which the spatial relation is provided is a CSI-RS; and
remaining bits in the second octet serve as the identifier of the reference signal resource set for the CSI-RS; and
if the first bit in the second octet is set to a second state:
if a second bit in the second octet is set to the first state:
the first bit and the second bit serve as the indication of the type of reference signal for which the spatial relation is provided and the type of reference signal for which the spatial relation is provided is a SSB; and
remaining bits in the second octet serve as the identifier of the reference signal resource set for the SSB; and
if the second bit in the second octet is set to the second state:
the first bit and the second bit serve as the indication of the type of reference signal for which the spatial relation is provided and the type of reference signal for which the spatial relation is provided is a SRS; and
all but one of the remaining bits in the second octet serve as the identifier of the reference signal resource set for the SRS.
5. The method of claim 1 wherein:
a first bit in the second octet is set to a first state such that the first bit serves as the indication of the type of reference signal for which the spatial relation is provided and the type of reference signal for which the spatial relation is provided is a CSI-RS; and
remaining bits in the second octet serve as the identifier of the reference signal resource set for the CSI-RS.
6. The method of claim 1 wherein:
a first bit in the second octet is set to a second state;
a second bit in the second octet is set to a first state such that the first bit and the second bit serve as the indication of the type of reference signal for which the spatial relation is provided and the type of reference signal for which the spatial relation is provided is a SSB; and
remaining bits in the second octet serve as the identifier of the reference signal resource set for the SSB.
7. The method of claim 1 wherein:
a first bit in the second octet is set to a second state;
a second bit in the second octet is set to the second state such that the first bit and the second bit serve as the indication of the type of reference signal for which the spatial relation is provided and the type of reference signal for which the spatial relation is provided is a SRS; and
all but one of the remaining bits in the second octet serve as the identifier of the reference signal resource set for the SRS.
8. The method of claim 1 wherein:
if a first bit of an octet of the MAC CE is set to a first state, remaining bits in the octet comprise a first set of fields;
if the first bit of the octet is set to a second state and a second bit of the octet is set to the first state, remaining bits in the octet comprise a second set of fields; and
if the first bit of the octet is set to the second state and the second bit of the octet is set to the second state, remaining bits in the octet comprise a third set of fields.
9. The method of claim 8 wherein the first set of fields comprises a field comprising bits providing an identifier of a CSI-RS resource set for which the spatial relation is indicated.
10. The method of claim 8 wherein the second set of fields comprises a field comprising bits providing an identifier of a SSB resource set for which the spatial relation is indicated.
11. The method of claim 8 wherein the third set of fields comprises a field comprising bits providing an identifier of a SRS resource set for which the spatial relation is indicated.
12. The method of claim 1 wherein the indication is an indication to activate the semi-persistent sounding reference signal resource set, and the method further comprises transmitting a sounding reference signal on the activated semi-persistent sounding reference signal resource set.
13. A wireless device for a cellular communications network, the wireless device comprising:
an interface comprising radio front end circuitry; and
processing circuitry associated with the interface, the processing circuitry configured to cause the wireless device to:
receive, from a network node via the interface, a Medium Access Control, MAC, Control Element, CE, comprising:
an indication of a semi-persistent sounding reference signal resource set to be activated or deactivated; and
information that indicates a spatial relation for the semi-persistent sounding reference signal resource set to be activated or deactivated;
wherein the MAC CE comprises:
a first octet that comprises the indication of the semi-persistent sounding reference signal resource set to be activated or deactivated; and
a second octet that comprises an indication of a type of reference signal for which the spatial relation is provided and an identifier of a reference signal resource set for the type of reference signal for which the spatial relation is provided;
when the indication of the type of reference signal is set to “1”, the identifier of the reference signal resource set comprises a Channel State Information Reference Signal, CSI-RS, resource index; and
when the indication of the type of reference signal is set to “0”, the identifier of the reference signal resource set comprises one or more of: Synchronization Signal Block, SSB, index; and Sounding Reference Signal, SRS, resource index.
14. A method of operation of a network node in a cellular communications network, comprising:
transmitting, to a wireless device, a Medium Access Control, MAC, Control Element, CE, comprising:
an indication of a semi-persistent sounding reference signal resource set to be activated or deactivated; and
information that indicates a spatial relation for the semi-persistent sounding reference signal resource set to be activated or deactivated;
wherein the MAC CE comprises:
a first octet that comprises the indication of the semi-persistent sounding reference signal resource set to be activated or deactivated; and
a second octet that comprises an indication of a type of reference signal for which the spatial relation is provided and an identifier of a reference signal resource set for the type of reference signal for which the spatial relation is provided;
when the indication of the type of reference signal is set to “1”, the identifier of the reference signal resource set comprises a Channel State Information Reference Signal, CSI-RS, resource index; and
when the indication of the type of reference signal is set to “0”, the identifier of the reference signal resource set comprises one or more of: Synchronization Signal Block, SSB, index; and Sounding Reference Signal, SRS, resource index.
15. The method of claim 14 wherein:
if a first bit in the second octet is set to a first state:
the first bit serves as the indication of the type of reference signal for which the spatial relation is provided and the type of reference signal for which the spatial relation is provided is a CSI-RS; and
remaining bits in the second octet serve as the identifier of the reference signal resource set for the CSI-RS; and
if the first bit in the second octet is set to a second state:
if a second bit in the second octet is set to the first state:
the first bit and the second bit serve as the indication of the type of reference signal for which the spatial relation is provided and the type of reference signal for which the spatial relation is provided is a SSB; and
remaining bits in the second octet serve as the identifier of the reference signal resource set for the SSB; and
if the second bit in the second octet is set to the second state:
the first bit and the second bit serve as the indication of the type of reference signal for which the spatial relation is provided and the type of reference signal for which the spatial relation is provided is a SRS; and
all but one of the remaining bits in the second octet serve as the identifier of the reference signal resource set for the SRS.