Method and apparatus to enable CSI reporting in wireless communication systems
A user equipment (UE) in a wireless communication system receives, from a base station (BS), CSI feedback configuration information; and deriving, based on the CSI feedback configuration information, the CSI feedback including a precoding matrix indicator (PMI), transmitting, to the BS via an uplink channel, the CSI feedback including the PMI, wherein, for each layer l=1, 2, . . . , v, the PMI indicates K NZ,l non-zero (NZ) coefficients out of a total of 2LM v coefficients, each of which is represented as c l,i,m =p l,i,m (1) p l,i,m (2) ϕ l,i,m , the K NZ,l NZ coefficients are partitioned into two groups (G 0 and G 1 ), and for each group G r , r∈{0,1}, one p l,i,m (1) value is indicated, where v is a rank value, p l,i,m (1) is a first amplitude coefficient, p l,i,m (2) is a second amplitude coefficient, and ϕ l,i,m is a phase coefficient.
1. A method performed by a terminal in a communication system, the method comprising;
receiving, from a base station, codebook configuration information for reporting of information associated with a precoding matrix indicator (PMI);
identifying first amplitude coefficients p l (1) and second amplitude coefficients p l,i,m (2) based on the codebook configuration information; and
transmitting, to the base station, the information associated with the PMI for indicating the first amplitude coefficients p l (1) and second amplitude coefficients p l,i,m (2) ,
wherein, for each layer l=1, 2, . . . , v, each of two first amplitude coefficients p l (1) corresponds to each of a first group of coefficients and a second group of coefficients, and
wherein the first group of coefficients includes a first subset of the second amplitude coefficients p l,i,m (2) with an index i=0, 1, . . . , L−1, and the second group of coefficients includes a second subset of the second amplitude coefficients p l,i,m (2) with an index i=L, L+1, . . . , 2L−1.
2. The method of claim 1 , wherein, for each layer l=1, 2, . . . , v, one of the two first amplitude coefficients p l (1) corresponding to a group including a strongest coefficient among the second amplitude coefficients p l,i,m (2) equals to 1 and is not reported.
3. The method of claim 2 , wherein, for each layer l=1, 2, . . . , v,
a remaining first amplitude coefficient p l (1) is reported using an indicator with 4 bits, and
K NZ −1 second amplitude coefficients p l,i,m (2) are reported using indicators each with 3 bits, where K NZ is a number of non-zero second amplitude coefficients.
4. The method of claim 3 , wherein,
the indicator with 4 bits indicates one of
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where R denotes a reserved state, and
the indicators each with 3 bits indicate one of
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5. The method of claim 1 , wherein the information associated with the PMI further indicates phase coefficients ϕ l,i,m , and
wherein the first group of coefficients further includes a first subset of the phase coefficients ϕ l,i,m with an index i=0, 1, . . . , L−1, and the second group of coefficients further includes a second subset of the phase coefficients ϕ l,i,m with an index i=L, L+1, . . . , 2L−1.
6. A method performed by a base station in a communication system, the method comprising:
transmitting, to a terminal, codebook configuration information for reporting of information associated with a precoding matrix indicator (PMI); and
receiving, from the terminal, the information associated with the PMI for indicating a first amplitude coefficients p l (1) and second amplitude coefficients p l,i,m (2) identified based on the codebook configuration information,
wherein, for each layer l=1, 2, . . . , v, each of two first amplitude coefficients p l (1) corresponds to each of a first group of coefficients and a second group of coefficients, and
wherein a first group of coefficients includes a first subset of the second amplitude coefficients p l,i,m (2) with an index i=0, 1, . . . , L−1, and a second group of coefficients includes a second subset of the second amplitude coefficients p l,i,m (2) with an index i=L, L+1, . . . , 2L−1.
7. The method of claim 6 , wherein, for each layer l=1, 2, . . . , v, one of the two first amplitude coefficients p l (1) corresponding to a group including a strongest coefficient among the second amplitude coefficients p l,i,m (2) equals to 1 and is not reported.
8. The method of claim 7 , wherein, for each layer l=1, 2, . . . , v,
a remaining first amplitude coefficient p l (1) is reported using an indicator with 4 bits, and
K NZ −1 second amplitude coefficients are reported using indicators each with 3 bits, where K NZ is a number of non-zero second amplitude coefficients.
9. The method of claim 8 , wherein,
the indicator with 4 bits indicates one of
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where R denotes a reserved state, and
the indicators each with 3 bits indicate one of
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10. The method of claim 6 , wherein the information associated with the PMI further indicates phase coefficients ϕ l,i,m , and
wherein the first group of coefficients further includes a first subset of the phase coefficients ϕ l,i,m with an index i=0, 1, . . . , L−1, and the second group of coefficients further includes a second subset of the phase coefficients ϕ l,i,m with an index i=L, L+1, . . . , 2L−1.
11. A terminal in a communication system, the terminal comprising:
a transceiver; and
a controller configured to:
receive, from a base station, codebook configuration information for reporting of information associated with a precoding matrix indicator (PMI),
identify first amplitude coefficients p l (1) and second amplitude coefficients p l,i,m (2) based on the codebook configuration information,
transmit, to the base station, the information associated with the PMI for indicating) the first amplitude coefficients p l (1) and second amplitude coefficients p l,i,m (2) ,
wherein, for each layer l=1, 2, . . . , v, each of two first amplitude coefficients p l (1) corresponds to each of a first group of coefficients and a second group of coefficients, and
wherein the first group of coefficients includes a first subset of the second amplitude coefficients p l,i,m (2) with an index i=0, 1, . . . , L−1, and the second group of coefficients includes a second subset of the second amplitude coefficients p l,i,m (2) with an index i=L, L+1, . . . , 2L−1.
12. The terminal of claim 11 , wherein, for each layer l=1, 2, . . . , v, one of the two first amplitude coefficients p l (1) corresponding to a group including a strongest coefficient among the second amplitude coefficients p l,i,m (2) equals to 1 and is not reported.
13. The terminal of claim 12 , wherein, for each layer l=1, 2, . . . , v,
a remaining first amplitude coefficient p l (1) is reported using an indicator with 4 bits, and
K NZ −1 second amplitude coefficients p l,i,m (2) are reported using indicators each with 3 bits, where K NZ is a number of non-zero second amplitude coefficients.
14. The terminal of claim 13 , wherein,
the indicator with 4 bits indicates one of
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1
2
1
4
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1
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,
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,
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1
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,
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1
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)
1
4
,
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1
2
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1
4
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1
}
,
where R denotes a reserved state, and
the indicators each with 3 bits indicate one of
{
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1
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8
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1
6
4
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15. A base station in a communication system, the base station comprising:
a transceiver; and
a controller configured to:
transmit, to a terminal, codebook configuration information for reporting of information associated with a precoding matrix indicator (PMI),
receive, from the terminal, the information associated with the PMI for indicating a first amplitude coefficients p l (1) and second amplitude coefficients p l,i,m (2) identified based on the codebook configuration information,
wherein, for each layer l=1, 2, . . . , v, each of two first amplitude coefficients p l (1) corresponds to each of a first group of coefficients and a second group of coefficients, and
wherein a first group of coefficients includes a first subset of the second amplitude coefficients p l,i,m (2) with an index i=0, 1, . . . , L−1, and a second group of coefficients includes a second subset of the second amplitude coefficients p l,i,m (2) with an index i=L, L+1, . . . , 2L−1.