Method and systems for conveying scheduling information of overlapping co-scheduled users in an OFDMA-MU-MIMO system
View Patent ↗Methods and systems for conveying or transmitting to any given user in an OFDMA-MU-MIMO system scheduling information of other co-scheduled users to permit the user to perform error-correction on received data and/or interference reduction on its received signals. The scheduling information can include resource block assignment, modulation constellations employed, coding rates employed, power levels utilized and precoder matrix indices used. Further, the scheduling information can be conveyed in part through dedicated reference symbol layers or pilot streams. Moreover, a base station may transmit a preliminary estimate of the total number of users the base station expects to schedule, or an upper-bound on the total number of users, to the MU-MIMO users to permit the MU-MIMO users to determine preferred precoder matrix indices and indications of channel quality indices.
1. A method implemented in a base station for conveying scheduling information in an orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system, the method comprising:
transmitting to a first user equipment (UE) the scheduling information including first scheduling information of the first UE and at least a portion of second scheduling information of at least one second UE,
wherein the scheduling information includes at least one of a resource block (RB) assigned to the first UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the first UE,
wherein the indication of one or more dedicated RS layers comprises an allocated pilot stream index (PSI),
wherein at least part of the scheduling information is conveyed by a four-bit index that identifies the number of said streams and the PSI,
wherein said four-bit index further identifies a modulation constellation assigned to the second UE in case the number of streams is 2, and
wherein a part of the scheduling information is conveyed according to a table comprising:
Modulation
Four-bit
Number of
constellation of the
index
streams
Allocated PSI
second UE
0b0000
2 streams
stream1
QPSK
0b0001
2 streams
stream1
16QAM
0b0010
2 streams
stream1
64QAM
0b0011
2 streams
stream1
Unknown or
not available
0b0100
2 streams
stream2
QPSK
0b0101
2 streams
stream2
16QAM
0b0110
2 streams
stream2
64QAM
0b0111
2 streams
stream2
Unknown or
not available
0b1000
3 streams
stream1
—
0b1001
3 streams
stream2
—
0b1010
3 streams
stream3
—
0b1011
4 streams
stream1
—
0b1100
4 streams
stream2
—
0b1101
4 streams
stream3
—
0b1110
4 streams
stream4
—
0b1111
Unknown or not
Unknown or
Unknown or
available
not available
not available
where QPSK stands for quadrature phase-shift keying and QAM stands for quadrature amplitude modulation.
2. The method of claim 1 ,
wherein the second UE is an overlapping UE that is assigned at least one RB that overlaps with at least one RB assigned to the first UE,
wherein an RB is a set of subcarriers and orthogonal frequency-division multiplexing (OFDM) symbols.
3. The method of claim 1 ,
wherein the scheduling information further includes at least one of modulation constellation of the first UE, a coding rate of the first UE, a precoder matrix index (PMI) of the first UE, and a transmit power value of the first UE.
4. The method of claim 3 ,
wherein at least one of the PMI and the transmit power value is transmitted to the first UE using dedicated reference symbol (RS) layers,
wherein each of the dedicated RS layers is precoded with a precoder and is transmitted on a portion of an RB.
5. A base station for conveying scheduling information in an orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system, comprising:
a transmission unit to transmit to a first user equipment (UE) the scheduling information including first scheduling information of the first UE and at least a portion of second scheduling information of at least one second UE,
wherein the scheduling information includes at least one of resource block (RB) assigned to the first UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the first UE,
wherein the indication of one or more dedicated RS layers comprises an allocated pilot stream index (PSI),
wherein at least part of the scheduling information is conveyed by a four-bit index that identifies the number of said streams and the PSI,
wherein said four-bit index further identifies a modulation constellation assigned to the second UE in case the number of streams is 2, and
wherein a part of the scheduling information is conveyed according to a table comprising:
Modulation
Four-bit
Number of
Allocated
constellation of
index
streams
PSI
the second UE
0b0000
2 streams
stream1
QPSK
0b0001
2 streams
stream1
16 QAM
0b0010
2 streams
stream1
64 QAM
0b0011
2 streams
stream1
Unknown or
not available
0b0100
2 streams
stream2
QPSK
0b0101
2 streams
stream2
16 QAM
0b0110
2 streams
stream2
64 QAM
0b0111
2 streams
stream2
Unknown or
not available
0b1000
3 streams
stream1
—
0b1001
3 streams
stream2
—
0b1010
3 streams
stream3
—
0b1011
4 streams
stream1
—
0b1100
4 streams
stream2
—
0b1101
4 streams
stream3
—
0b1110
4 streams
stream4
—
0b1111
Unknown or
Unknown or
Unknown or
not available
not available
not available
where QPSK stands for quadrature phase-shift keying and QAM stands for quadrature amplitude modulation.
6. An orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system for conveying scheduling information, comprising:
a first user equipment (UE);
a second UE;
a base station configured to transmit to the first UE the scheduling information including first scheduling information of the first UE and at least a portion of second scheduling information of the second UE,
wherein the scheduling information includes at least one of resource block (RB) assigned to the first UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the first UE,
wherein the indication of one or more dedicated RS layers comprises an allocated pilot stream index (PSI),
wherein at least part of the scheduling information is conveyed by a four-bit index that identifies the number of said streams and the PSI,
wherein said four-bit index further identifies a modulation constellation assigned to the second UE in case the number of streams is 2, and
wherein a part of the scheduling information is conveyed according to a table comprising:
Modulation
Four-bit
Number of
Allocated
constellation of
index
streams
PSI
the second UE
0b0000
2 streams
stream1
QPSK
0b0001
2 streams
stream1
16 QAM
0b0010
2 streams
stream1
64 QAM
0b0011
2 streams
stream1
Unknown or
not available
0b0100
2 streams
stream2
QPSK
0b0101
2 streams
stream2
16 QAM
0b0110
2 streams
stream2
64 QAM
0b0111
2 streams
stream2
Unknown or
not available
0b1000
3 streams
stream1
—
0b1001
3 streams
stream2
—
0b1010
3 streams
stream3
—
0b1011
4 streams
stream1
—
0b1100
4 streams
stream2
—
0b1101
4 streams
stream3
—
0b1110
4 streams
stream4
—
0b1111
Unknown or
Unknown or
Unknown or
not available
not available
not available
where QPSK stands for quadrature phase-shift keying and QAM stands for quadrature amplitude modulation.
7. A user equipment (UE) used in an orthogonal frequency division multiple access (OFDMA) multi-user (MU)-multiple input multiple output (MIMO) system conveying scheduling information from a base station, comprising:
a receiving unit to receive the scheduling information including first scheduling information of the UE and at least a portion of second scheduling information of at least one second UE,
wherein the scheduling information includes at least one of resource block (RB) assigned to the UE, the number of streams, and an indication of one or more dedicated reference symbol (RS) layers assigned to the UE,
wherein the indication of one or more dedicated RS layers comprises an allocated pilot stream index (PSI),
wherein at least part of the scheduling information is conveyed by a four-bit index that identifies the number of said streams and the PSI,
wherein said four-bit index further identifies a modulation constellation assigned to the second UE in case the number of streams is 2, and
wherein a part of the scheduling information is conveyed according to a table comprising:
Modulation
Four-bit
Number of
Allocated
constellation of
index
streams
PSI
the second UE
0b0000
2 streams
stream1
QPSK
0b0001
2 streams
stream1
16 QAM
0b0010
2 streams
stream1
64 QAM
0b0011
2 streams
stream1
Unknown or
not available
0b0100
2 streams
stream2
QPSK
0b0101
2 streams
stream2
16 QAM
0b0110
2 streams
stream2
64 QAM
0b0111
2 streams
stream2
Unknown or
not available
0b1000
3 streams
stream1
—
0b1001
3 streams
stream2
—
0b1010
3 streams
stream3
—
0b1011
4 streams
stream1
—
0b1100
4 streams
stream2
—
0b1101
4 streams
stream3
—
0b1110
4 streams
stream4
—
0b1111
Unknown or
Unknown or
Unknown or
not available
not available
not available
where QPSK stands for quadrature phase-shift keying and QAM stands for quadrature amplitude modulation.