Uplink multi-user multiple-input-multiple-output (MU-MIMO) configurations
An apparatus for a base station configured for operation in a C-RAN includes processing circuitry coupled to a memory. To configure the base station for multi-user multiple input multiple output (MU-MIMO) signal processing, the processing circuitry is to decode a plurality of sounding reference signals received from a corresponding plurality of UEs via a corresponding plurality of channels. The plurality of channels are estimated based on the plurality of sounding reference signals. A beamforming matrix is determined based on a channel matrix corresponding to the plurality of channels. Beamforming is performed on a plurality of uplink (UL) data streams received from the plurality of UEs, to generate a plurality of beamformed streams. The beamforming is based on the beamforming matrix. Interference suppression is performed on the plurality of beamformed streams to generate a plurality of output data streams. The interference suppression is based on non-orthogonal DMRSs received from the UEs.
1. An apparatus for a base station configured for operation in a centralized radio access network (C-RAN), the apparatus comprising:
processing circuitry, wherein to configure the base station for multiple user, multiple-input-multiple-output (MU-MIMO) signal processing in the C-RAN, the processing circuitry is to:
determine at a baseband unit (BBU) function of the base station, a beamforming matrix based on a plurality of sounding reference signals, the plurality of sounding reference signals received from a corresponding plurality of user equipments (UEs) via a corresponding plurality of channels;
perform at a remote radio unit (RRU) function of the base station, beamforming on a plurality of uplink (UL) data streams received from the plurality of UEs, to generate a plurality of beamformed streams, the beamforming based on the beamforming matrix;
perform at the RRU function of the base station, interference suppression on the plurality of beamformed streams to generate a plurality of output data streams, the interference suppression based on non-orthogonal demodulation reference signals (DMRSs) received from the plurality of UEs; and
decode UL data using the plurality of output data streams; and
a memory coupled to the processing circuitry and configured to store the plurality of sounding reference signals.
2. The apparatus of claim 1 , wherein to determine the beamforming matrix, the processing circuitry is to:
determine a first received signal vector based on a first set of the plurality of channels associated with a first set of UEs of the plurality of UEs, the first set of UEs configured with a first scrambling identity number (nSCID); and
determine a second received signal vector based on a second set of the plurality of channels associated with a second set of UEs of the plurality of UEs, the second set of UEs configured with a second nSCID;
wherein the first nSCID is different from the second nSCID.
3. The apparatus of claim 2 , wherein to determine the beamforming matrix, the processing circuitry is to:
determine orthogonal projection matrices based on the first received signal vector and the second received signal vector.
4. The apparatus of claim 3 , wherein the beamforming matrix is a block diagonalization beamforming matrix based on the orthogonal projection matrices.
5. The apparatus of claim 3 , wherein the beamforming matrix is a zero-forcing beamforming matrix based on a zero-forcing operation on a channel matrix of the plurality of channels.
6. The apparatus of claim 1 , wherein to perform the interference suppression, the processing circuitry is to:
determine channel state information based on the non-orthogonal DMRSs received from the plurality of UEs.
7. The apparatus of claim 6 , wherein to perform the interference suppression, the processing circuitry is to:
perform minimum mean square error interference rejection (MMSE-IRC) on the plurality of beamformed streams based on the channel state information.
8. An apparatus for a base station configured for operation in a centralized radio access network (C-RAN), the apparatus comprising:
processing circuitry, wherein to configure the base station for multi-user multiple-input-multiple-output (MU-MIMO) signal processing in the C-RAN, the processing circuitry is to:
decode a plurality of sounding reference signals received from a corresponding plurality of user equipments (UEs) via a corresponding plurality of channels;
estimate the plurality of channels based on the plurality of sounding reference signals;
determine a beamforming matrix based on a signal vector corresponding to the plurality of channels;
perform beamforming on a plurality of uplink (UL) data streams received from the plurality of UEs, to generate a plurality of beamformed streams, the beamforming based on the beamforming matrix,
perform interference suppression on the plurality of beamformed streams to generate a plurality of output data streams, the interference suppression based on non-orthogonal demodulation reference signals (DMRSs) received from the plurality of UEs; and
decode UL data using the plurality of output data streams, and
a memory coupled to the processing circuitry and configured to store the plurality of sounding reference signals.
9. The apparatus of claim 8 , wherein to determine the beamforming matrix, the processing circuitry is to:
determine a first channel matrix based on a first set of the plurality of channels associated with a first set of UEs of the plurality of UEs, the first set of UEs configured with a first scrambling identity number (nSCID); and
determine a second channel matrix based on a second set of the plurality of channels associated with a second set of UEs of the plurality of UEs, the second set of UEs configured with a second nSCID;
wherein the first nSCID is different from the second nSCID.
10. The apparatus of claim 9 , wherein to determine the beamforming matrix, the processing circuitry is to:
determine orthogonal projection matrices based on the first channel matrix and the second channel matrix.
11. The apparatus of claim 10 , wherein the beamforming matrix is a block diagonalization beamforming matrix based on the orthogonal projection matrices.
12. The apparatus of claim 10 , wherein the beamforming matrix is a zero-forcing beamforming matrix based on a zero-forcing operation on a channel matrix of the plurality of channels.
13. The apparatus of claim 8 , wherein to perform the interference suppression, the processing circuitry is to:
determine channel state information based on the non-orthogonal DMRSs received from the plurality of UEs.
14. The apparatus of claim 13 , wherein to perform the interference suppression, the processing circuitry is to:
perform minimum mean square error interference rejection combining (MMSE-IRC) on the plurality of beamformed streams based on the channel state information.
15. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of a base station in a centralized radio access network (C-RAN), the instructions to configure the base station for multi-user multiple-input-multiple-output (MU-MIMO) signal processing in the C-RAN and to cause the base station to perform operations comprising:
decoding a plurality of sounding reference signals received from a corresponding plurality of user equipments (UEs) via a corresponding plurality of channels;
estimating the plurality of channels based on the plurality of sounding reference signals;
determining a beamforming matrix based on a channel matrix corresponding to the plurality of channels;
performing beamforming on a plurality of uplink (UL) data streams received from the plurality of UEs, to generate a plurality of beamformed streams, the beamforming based on the beamforming matrix;
performing interference suppression on the plurality of beamformed streams to generate a plurality of output data streams, the interference suppression based on non-orthogonal demodulation reference signals (DMRSs) received from the plurality of UEs; and
decoding UL data using the plurality of output data streams.
16. The non-transitory computer-readable storage medium of claim 15 , the operations further comprising:
determining a first channel matrix based on a first set of the plurality of channels associated with a first set of UEs of the plurality of UEs, the first set of UEs configured with a first scrambling identity number (nSCID); and
determining a second channel matrix based on a second set of the plurality of channels associated with a second set of UEs of the plurality of UEs, the second set of UEs configured with a second nSCID;
wherein the first nSCID is different from the second nSCID.
17. The non-transitory computer-readable storage medium of claim 16 , the operations further comprising:
determining orthogonal projection matrices based on the first channel matrix and the second channel matrix.
18. The non-transitory computer-readable storage medium of claim 17 , wherein the beamforming matrix is a block diagonalization beamforming matrix based on the orthogonal projection matrices.
19. The non-transitory computer-readable storage medium of claim 17 , wherein the beamforming matrix is a zero-forcing beamforming matrix based on a zero-forcing operation on a channel matrix of the plurality of channels.
20. The non-transitory computer-readable storage medium of claim 15 , the operations further comprising:
determining channel state information based on the non-orthogonal DMRSs received from the plurality of UEs; and
performing minimum mean square error interference rejection combining (MMSE-IRC) on the plurality of beamformed streams based on the channel state information.