CDM8 based CSI-RS designs for MIMO
A network node, wireless device, base station, user equipment and corresponding methods are provided. The network node includes processing circuitry configured to: select a first set and second set of reference signal resources in a subframe and aggregate the first set and second set of reference signal resources in the subframe to form a code division multiplexing, CDM, aggregation configuration. The first set and second set of reference signal resources in the subframe satisfy a temporal criterion such that any two resource elements in the first set and second set of reference signal resources have up to a maximum time separation of six OFDM symbols. The first set and second set of reference signal resources in the subframe satisfy a frequency criterion such that any two resource elements in the first set and second set of reference signal resources have up to a maximum frequency separation of six subcarriers.
1. A base station, comprising:
processing circuitry configured to:
signal a code division multiplexing (CDM) configuration for a CDM-8 design for at least twenty four Channel System Information-Reference Signal (CSI-RS) antenna ports, the CDM configuration corresponding to an aggregated first set and second set of reference signal resources in a subframe;
the aggregated first set and second set of reference signal resources in the subframe satisfying a temporal criterion such that each resource element in the first set has up to a maximum time separation of six orthogonal frequency division multiplexing (OFDM) symbols with each resource element in the second set of reference signal resources; and
the aggregated first set and second set of reference signal resources in the subframe satisfying a frequency criterion such that each resource element in the first set has up to a maximum frequency separation of six subcarriers with each resource element in the second set of reference signal resources.
2. The base station of claim 1 , wherein the first set of reference signal resources corresponds to a first portion of a first reference signal configuration; and
the second set of reference signal resources corresponds to a second portion of a second reference signal configuration.
3. The base station of claim 2 , wherein the first set of reference signal resources is at least a first channel state information-reference signal, CSI-RS, configuration; and
the second set of reference signal resources is at least a second CSI-RS configuration different from the at least first CSI-RS configuration.
4. The base station of claim 1 , wherein the first set of reference signal resources in the subframe includes a subset of resources from an eight port CSI-RS resource configuration;
the second set of reference signal resources in the subframe includes a subset of resources in a different eight port CSI-RS resource configuration different from the eight port CSI-RS resource configuration corresponding to the first set of reference signal resources; and
the CDM configuration having an orthogonal cover code of length eight.
5. The base station of claim 1 , wherein the processing circuitry is further configured to communicate the CDM configuration to a user equipment.
6. The base station of claim 1 , wherein the CDM configuration is an aggregation of two CDM-4 groups.
7. A method for a base station, the method comprising:
signaling a code division multiplexing (CDM) configuration for a CDM-8 design for at least twenty four Channel System Information-Reference Signal (CSI-RS) antenna ports, the CDM configuration corresponding to an aggregated first set and second set of reference signal resources in a subframe;
the aggregated first set and second set of reference signal resources in the subframe satisfying a temporal criterion such that each resource element in the first set has up to a maximum time separation of six orthogonal frequency division multiplexing (OFDM) symbols with each resource element in the second set of reference signal resources; and
the aggregated first set and second set of reference signal resources in the subframe satisfying a frequency criterion such that each resource element in the first set has up to a maximum frequency separation of six subcarriers with each resource element in the second set of reference signal resources.
8. The method of claim 7 , wherein the first set of reference signal resources corresponds to a first portion of a first reference signal configuration; and
the second set of reference signal resources corresponds to a second portion of a second reference signal configuration.
9. The method of claim 8 , wherein the first set of reference signal resources is at least a first channel state information-reference signal, CSI-RS, configuration; and
the second set of reference signal resources is at least a second CSI-RS configuration different from the at least first CSI-RS configuration.
10. The method of claim 7 , wherein the first set of reference signal resources in the subframe includes a subset of resources from an eight port CSI-RS resource configuration;
the second set of reference signal resources in the subframe includes a subset of resources in a different eight port CSI-RS resource configuration different from the eight port CSI-RS resource configuration corresponding to the first set of reference signal resources; and
the CDM configuration having an orthogonal cover code of length eight.
11. The method of claim 7 , further comprising communicating the CDM configuration to a user equipment.
12. The method of claim 7 , wherein the CDM configuration is an aggregation of two CDM-4 groups.
13. A user equipment, comprising:
processing circuitry configured to:
receive a code division multiplexing (CDM) configuration for a CDM-8 design for at least twenty four Channel System Information-Reference Signal (CSI-RS) antenna ports, the CDM configuration corresponding to an aggregated first set and second set of reference signal resources in a subframe;
perform channel measurements based on the CDM configuration;
the aggregated first set and second set of reference signal resources in the subframe satisfying a temporal criterion such that each resource element in the first set has up to a maximum time separation of six orthogonal frequency division multiplexing (OFDM) symbols with each resource element in the second set of reference signal resources; and
the aggregated first set and second set of reference signal resources in the subframe satisfying a frequency criterion such that each resource element in the first set has up to a maximum frequency separation of six subcarriers with each resource element in the second set of reference signal resources.
14. The user equipment of claim 13 , wherein the first set of reference signal resources corresponds to a first portion of a first reference signal configuration; and
the second set of reference signal resources corresponds to a second portion of a second reference signal configuration.
15. The user equipment of claim 14 , wherein the first set of reference signal resources is at least a first channel state information-reference signal, CSI-RS, configuration; and
the second set of reference signal resources is at least a second CSI-RS configuration different from the at least first CSI-RS configuration.
16. The user equipment of claim 13 , wherein the first set of reference signal resources in the subframe includes a subset of resources from an eight port CSI-RS resource configuration;
the second set of reference signal resources in the subframe includes a subset of resources in a different eight port CSI-RS resource configuration different from the eight port CSI-RS resource configuration corresponding to the first set of reference signal resources; and
the CDM configuration having an orthogonal cover code of length eight.
17. The user equipment of claim 13 , wherein the processing circuitry is further configured to map the aggregated first set and second set of reference signal resources in the subframe to a plurality of antenna ports.
18. The user equipment of claim 13 , wherein the CDM configuration is an aggregation of two CDM-4 groups.