CSI report with time domain channel information
Aspects of the disclosure relate to transmission of a single CSI report that includes time domain channel information obtained from a plurality of CSI-RSs received by a UE over time. For example, each of the CSI-RSs may be associated with a different respective time resource (e.g., each CSI-RS is received at a different respective time). The UE may obtain a plurality of CSI values based on the plurality of CSI-RSs and generate the time domain channel information from the plurality of CSI values. In some examples, the time domain channel information includes the plurality of CSI values. In other examples, the time domain channel information includes compressed channel information based on the plurality of CSI values. A base station may then utilize the time domain channel information included in the CSI report for scheduling downlink data transmissions to the UE.
1 . A user equipment (UE) configured for wireless communication, comprising:
a transceiver;
a memory; and
a processor coupled to the transceiver and the memory, wherein the processor and the memory are configured to:
receive a plurality of reference signals, each associated with a different time resource of a plurality of time resources;
transmit a channel state information (CSI) report comprising time domain channel information based on a plurality of CSI values obtained based on the plurality of reference signals, wherein the time domain channel information comprises compressed channel information based on the plurality of CSI values;
determine a long-term amplitude parameter from a number of CSI values including the plurality of CSI values and additional CSI values obtained prior to the plurality of CSI values, wherein the long-term amplitude parameter includes an average of the amplitudes of the number of CSI values, wherein the time domain channel information further comprises the at least one long-term amplitude parameter;
apply a time domain transform to the plurality of CSI values to produce a plurality of transform values;
select a plurality of taps from the plurality of transform values to produce a plurality of coefficients, wherein the plurality of coefficients comprises a main phase coefficient and a plurality of differential phase coefficients with respect to the main phase coefficient; and
quantize the main phase coefficient using a first quantization type to produce a main quantized phase coefficient and quantize the plurality of differential phase coefficients using a second quantization type to produce a plurality of quantized differential phase coefficients, wherein the compressed channel information comprises the main quantized phase coefficient and the quantized differential phase coefficients, wherein the first quantization type is different from the second quantization type and wherein the compressed channel information comprises respective indices of each of the plurality of taps.
2 . The UE of claim 1 , wherein the time domain channel information comprises the plurality of CSI values.
3 . The UE of claim 1 , wherein the processor and the memory are further configured to:
apply at least one of a spatial domain transform or a frequency domain transform to the plurality of quantized time domain coefficients to produce additional quantized coefficients, wherein the compressed channel information further comprises the additional quantized coefficients.
4 . The UE of claim 1 , wherein the processor and the memory are further configured to:
apply at least one of a spatial domain transform or a frequency domain transform prior to the time domain transform to produce additional quantized coefficients, wherein the compressed channel information further comprises the additional quantized coefficients.
5 . The UE of claim 1 , wherein the plurality of CSI values comprise a respective set of CSI values for each sub-band of a plurality of sub-bands, and wherein the processor and the memory are further configured to:
apply the time domain transform to each of the respective sets of CSI values.
6 . The UE of claim 5 , wherein the processor and the memory are further configured to:
apply a different time domain transform to at least two of the respective sets of CSI values.
7 . The UE of claim 1 , wherein the plurality of CSI values comprise a respective set of CSI values for each of a plurality of CSI types including a channel state information reference signal (CSI-RS) resource indicator (CRI), a rank indicator (RI), a layer indicator (LI), a precoding matrix indicator (PMI), and a channel quality indicator (CQI), and wherein the time domain channel information is arranged in the CSI report in an order corresponding to the CRI, the RI, the LI, zero padding, the PMI, and the CQI.
8 . The UE of claim 7 , wherein the time domain channel information comprises a respective first entry for each of the plurality of CSI types and respective differential entries with respect to the respective first entry for each of the plurality of CSI types.
9 . A base station configured for wireless communication, comprising:
a transceiver;
a memory; and
a processor coupled to the transceiver and the memory, wherein the processor and the memory are configured to:
transmit a plurality of reference signals to a user equipment (UE), each of the plurality of reference signals being associated with a different time resource of a plurality of time resources;
receive a channel state information (CSI) report from the UE, the CSI report comprising time domain channel information based on a plurality of CSI values obtained based on the plurality of reference signals, wherein the time domain channel information comprises compressed channel information based on the plurality of CSI values, and wherein the compressed channel information comprises a main quantized phase coefficient, quantized differential phase coefficients, and at least one long-term amplitude parameter based on a number of CSI values including the plurality of CSI values and additional CSI values obtained prior to the plurality of CSI values, wherein the long-term amplitude parameter includes an average of the amplitudes of the number of CSI values; and
reconstruct the plurality of CSI values based on the compressed channel information.
10 . The base station of claim 9 , wherein the time domain channel information comprises the plurality of CSI values.
11 . The base station of claim 10 , wherein the plurality of CSI values comprise a respective set of CSI values for each of a plurality of CSI types, wherein the plurality of CSI types comprises a channel state information reference signal (CSI-RS) resource indicator (CRI), a rank indicator (RI), a layer indicator (LI), a precoding matrix indicator (PMI), and a channel quality indicator (CQI), and wherein the time domain channel information is arranged in the CSI report in an order corresponding to the CRI, the RI, the LI, zero padding, the PMI, and the CQI.
12 . The base station of claim 11 , wherein the time domain channel information comprises a respective first entry for each of the plurality of CSI types and respective differential entries with respect to the respective first entry for each of the plurality of CSI types.
13 . The base station of claim 9 , wherein the compressed channel information comprises a first quantized phase coefficient, quantized differential phase coefficients that are differential with respect to the first quantized phase coefficient, at least one long-term distribution parameter of a distribution function applied to a plurality of long-term amplitude coefficients obtained from a set of reference signals including the plurality of reference signals and additional reference signals transmitted prior to the plurality of reference signals, and a plurality of quantized short-term amplitude coefficients associated with the plurality of reference signals that are quantized based on the at least one long-term distribution parameter.
14 . The base station of claim 13 , wherein:
the compressed channel information further comprises at least one long-term differential distribution parameter of an additional distribution function applied to long-term differential amplitude coefficients obtained from the plurality of long-term amplitude coefficients, and
the plurality of quantized short-term amplitude coefficients comprise a first quantized short-term amplitude coefficient quantized based on the at least one long-term distribution parameter and a plurality of quantized differential coefficients that are differential with respect to the first quantized coefficient and quantized based on the at least one long-term differential distribution parameter.
15 . A method for wireless communication at a user equipment (UE), the method comprising:
receiving a plurality of reference signals, each associated with a different time resource of a plurality of time resources;
transmitting a channel state information (CSI) report comprising time domain channel information based on a plurality of CSI values obtained based on the plurality of reference signals, wherein the time domain channel information comprises compressed channel information based on the plurality of CSI values;
determining at least one long-term amplitude parameter from a number of CSI values including the plurality of CSI values and additional CSI values obtained prior to the plurality of CSI values, wherein the time domain channel information further comprises the at least one long-term amplitude parameter, wherein the long-term amplitude parameter includes an average of the amplitudes of the number of CSI values;
applying a time domain transform to the plurality of CSI values to produce a plurality of transform values;
selecting a plurality of taps from the plurality of transform values to produce a plurality of coefficients, wherein the plurality of coefficients comprises a main phase coefficient and a plurality of differential phase coefficients with respect to the main phase coefficient; and
quantizing the main phase coefficient using a first quantization type to produce a main quantized phase coefficient and quantize the plurality of differential phase coefficients using a second quantization type to produce a plurality of quantized differential phase coefficients, wherein the compressed channel information comprises the main quantized phase coefficient and the quantized differential phase coefficients, wherein the first quantization type is different from the second quantization type and wherein the compressed channel information comprises respective indices of each of the plurality of taps.
16 . The method of claim 15 , wherein the time domain channel information comprises the plurality of CSI values.
17 . A method for wireless communication at a base station, the method comprising:
transmitting a plurality of reference signals to a user equipment (UE), each of the plurality of reference signals being associated with a different time resource of a plurality of time resources;
receiving a channel state information (CSI) report from the UE, the CSI report comprising time domain channel information based on a plurality of CSI values obtained based on the plurality of reference signals, wherein the time domain channel information comprises compressed channel information based on the plurality of CSI values, and wherein the compressed channel information comprises a main quantized phase coefficient, quantized differential phase coefficients, and at least one long-term amplitude parameter based on a number of CSI values including the plurality of CSI values and additional CSI values obtained prior to the plurality of CSI values, wherein the long-term amplitude parameter includes an average of the amplitudes of the number of CSI values; and
reconstructing the plurality of CSI values based on the compressed channel information.