Systems and methods for enhancing efficient uplink MIMO performance and implementation for O-RAN-based radio access networks
A system and method of operating an Open Radio Access Network (O-RAN, in which O-RAN the system includes: a baseband unit (BBU) having an O-RAN centralized unit (O-CU) and an O-RAN distributed unit (O-DU); an O-RAN radio unit (O-RU) remote from the BBU; and a fronthaul interface between the O-RU and the BBU. A functional split of O-RAN functions respectively assigned to O-RU and O-DU for the fronthaul interface between the BBU and the O-RU is different for downlink (DL) and uplink (UL) so that at least one of i) demodulation reference signal (DM-RS)-based channel estimation is performed by the O-DU in the DL and by the O-RU in the UL, ii) equalization is performed by the O-DU in the DL and by the O-RU in the UL, and iii) demodulation is performed by the O-DU in the DL and by the O-RU in the UL.
1 . An Open Radio Access Network (O-RAN) system, comprising:
a baseband unit (BBU) having an O-RAN centralized unit (O-CU) and an O-RAN distributed unit (O-DU);
an O-RAN radio unit (O-RU) remote from the BBU; and
a fronthaul interface between the O-RU and the BBU;
wherein a functional split of O-RAN functions respectively assigned to O-RU and O-DU for the fronthaul interface between the BBU and the O-RU is different for downlink (DL) and uplink (UL), and wherein the system is configured such that i) demodulation reference signal (DM-RS)-based channel estimation is performed by the O-DU in the DL and by the O-RU in the UL, and ii) equalization is performed by the O-DU in the DL and by the O-RU in the UL.
2 . The system according to claim 1 , wherein the system is configured such that the O-DU transfers DM-RS information to the O-RU, the DM-RS information including DM-RS configuration parameters of the scheduled or paired UEs/layers are received by the O-RU, and the O-RU generates a DM-RS sequence using the DM-RS configuration parameters received from O-DU.
3 . The system according to claim 2 , wherein the system is configured such that the O-RU estimates the UL channels of the UE(s) and/or layer(s) transmitted at a current slot n using the DM-RS information.
4 . The system according to claim 3 , wherein the system is configured such that the O-RU equalizes the UL channels of the one or more UEs, the one or more layers, or both transmitted at a current slot n.
5 . The system according to claim 4 , wherein the system is configured such that the O-RU calculates a supplementary demodulation information and transfers the supplementary demodulation information along with an equalized signal stream to the O-DU.
6 . The system according to claim 5 , wherein the system is configured such that the O-DU performs a demodulation on a signal of slot n transferred from the O-RU and a L1/L2 processing on the demodulated signal.
7 . The system according to claim 1 , wherein the system is configured such that iii) demodulation is performed by the O-DU in the DL and by the O-RU in the UL.
8 . The system according to claim 7 , wherein the system is configured such that the O-DU transfer DM-RS information to the O-RU, the DM-RS information including DM-RS configuration parameters of the scheduled or paired UEs/layers are received by the O-RU, and the O-RU generates a DM-RS sequence using the DM-RS configuration parameters received from O-DU.
9 . The system according to claim 8 , wherein the system is configured such that the O-RU estimates the UL channels of the UE(s) and/or layer(s) transmitted at a current slot n using the DM-RS information.
10 . The system according to claim 9 , wherein the system is configured such that the O-RU equalizes the UL channels of the one or more UEs, the one or more layers, or both, transmitted at a current slot n.
11 . The system according to claim 10 , wherein the system is configured such that, prior to a slot n, the DU transfers modulation information to the RU and the O-RU performs demodulation on an equalized signal.
12 . A method of operating an Open Radio Access Network (O-RAN) system, comprising:
providing a baseband unit (BBU) having an O-RAN centralized unit (O-CU) and an O-RAN distributed unit (O-DU);
providing an O-RAN radio unit (O-RU) remote from the BBU; and
providing a fronthaul interface between the O-RU and the BBU;
wherein a functional split of O-RAN functions respectively assigned to O-RU and O-DU for the fronthaul interface between the BBU and the O-RU is different for downlink (DL) and uplink (UL), and wherein i) demodulation reference signal (DM-RS)-based channel estimation is performed by the O-DU in the DL and by the O-RU in the UL, and ii) equalization is performed by the O-DU in the DL and by the O-RU in the UL.
13 . The method according to claim 12 , wherein iii) demodulation is performed by the O-DU in the DL and by the O-RU in the UL.