Fronthaul interface for advanced split-radio access network (ran) systems

A method for use in a system comprising:

• a distributed unit (DU) to communicatively couple the system to a core network, the DU configured to implement at least some LAYER 2 functions for a wireless interface and at least some LAYER 1 functions for the wireless interface;
• and
• a plurality of remote units (RUs) to wirelessly transmit and receive radio frequency signals to and from user equipment (UE) using the wireless interface in connection with serving a cell, each of the RUs associated with at least one antenna and located remotely from the DU and at least one other RU, wherein each RU is configured to implement the LAYER 1 functions for the wireless interface that are not implemented in the DU;
• wherein the DU and RUs are communicatively coupled to each other over a fronthaul and are configured to communicate over the fronthaul using an Open Radio Access Network (O-RAN) fronthaul interface;
• and
• wherein the DU is configured to do the following in connection with wirelessly transmitting user data to a UE using less than all of the RUs:
• include, in a control-plane message for that UE that is communicated over the fronthaul, section fields that include a predetermined section extension;
• and
• include, in one or more user-plane messages for that UE that are communicated over the fronthaul and that are associated with the control-plane message for that UE, section fields that include the predetermined section extension;
• wherein each control-plane message that includes the predetermined section extension and the associated one or more user-plane messages include common header fields that contain a RU mask field for storing a bit mask comprising a plurality of bit positions, wherein each bit position is associated with a respective one of the RUs;
• wherein the method comprises doing the following at each RU:
• using the RU mask field included in any control-plane or user-plane message received by that RU that includes the predetermined section extension in order to determine if the received control-plane or user-plane message is intended for that RU;
• using the received control-plane or user-plane message to wirelessly transmit the user data to that UE using that RU, if the RU mask field indicates that the received control-plane or user-plane message is intended for that RU;
• and
• discarding the received control-plane or user-plane message, if the RU mask field indicates that the received control-plane message is not intended for that RU.

A system comprising:

• a distributed unit (DU) to communicatively couple the system to a core network, the DU configured to implement at least some LAYER 2 functions for a wireless interface and at least some LAYER 1 functions for the wireless interface;
• and
• a plurality of remote units (RUs) to wirelessly transmit and receive radio frequency signals to and from user equipment (UE) using the wireless interface in connection with serving a cell, each of the RUs associated with at least one antenna and located remotely from the DU and at least one other RU, wherein each RU is configured to implement the LAYER 1 functions for the wireless interface that are not implemented in the DU;
• wherein the DU and RUs are communicatively coupled to each other over a fronthaul and are configured to communicate over the fronthaul using an Open Radio Access Network (O-RAN) fronthaul interface;
• and
• wherein the DU is configured to do the following in connection with wirelessly transmitting user data to a UE using less than all of the RUs:
• include, in a control-plane message for that UE that is communicated over the fronthaul, section fields that include a predetermined section extension containing a RU mask field for storing a bit mask comprising a plurality of bit positions, wherein each bit position is associated with a respective one of the RUs;
• and
• include, in one or more user-plane messages for that UE that are communicated over the fronthaul and that are associated with the control-plane message for that UE, section fields that include the predetermined section extension;
• wherein the system is configured so that the section fields included in each control-plane message include a section identifier that is also included in one or more user-plane messages associated with that control-plane message;
• wherein each RU is configured to:
• use the RU mask field included in any control-plane message received by that RU that includes the predetermined section extension in order to determine if the received control-plane message is intended for that RU;
• identify one or more one user-plane message received by that RU that include the predetermined section extension that are associated with the received control-plane message based on the respective section identifiers included in the received control-plane message and the received one or more user-plane messages;
• use the received control-plane message and the associated received one or more user-plane messages to wirelessly transmit the user data to that UE using that RU, if the RU mask field indicates that the received control-plane message is intended for that RU;
• and
• discard the received control-plane message and the associated received one or more user-plane messages, if the RU mask field indicates that the received control-plane message is not intended for that RU.

A method for use in a system that comprises:

• a distributed unit (DU) to communicatively couple the system to a core network, the DU configured to implement at least some LAYER 2 functions for a wireless interface and at least some LAYER 1 functions for the wireless interface;
• and
• a plurality of remote units (RUs) to wirelessly transmit and receive radio frequency signals to and from user equipment (UE) using the wireless interface in connection with serving a cell, each of the RUs associated with at least one antenna and located remotely from the DU and at least one other RU, wherein each RU is configured to implement the LAYER 1 functions for the wireless interface that are not implemented in the DU;
• wherein the DU and RUs are communicatively coupled to each other over a fronthaul and are configured to communicate over the fronthaul using an Open Radio Access Network (O-RAN) fronthaul interface;
• and
• wherein the DU is configured to do the following in connection with wirelessly transmitting user data to a UE using less than all of the RUs:
• include, in a control-plane message for that UE that is communicated over the fronthaul, section fields that include a predetermined section extension containing a RU mask field for storing a bit mask comprising a plurality of bit positions, wherein each bit position is associated with a respective one of the RUs;
• and
• include, in one or more user-plane messages for that UE that are communicated over the O-RAN fronthaul and that are associated with the control-plane message for that UE, section fields that include the predetermined section extension;
• wherein the system is configured so that the section fields included in each control-plane message include a section identifier that is also included in one or more user-plane messages associated with that control-plane message;
• wherein the system is configured so that, for each control-plane message including the predetermined section extension, the section fields for that control-plane message include a section identifier that is also included in the section fields for the one or more user-plane messages associated with that control-plane message;
• wherein the method comprises doing the following at each RU:
• using the RU mask field included in any control-plane message received by that RU that includes the predetermined section extension in order to determine if the received control-plane message is intended for that RU;
• identifying one or more one user-plane message received by that RU that include the predetermined section extension that are associated with the received control-plane message based on the respective section identifiers included in the received control-plane message and the received one or more user-plane messages;
• using the received control-plane message and the associated received one or more user-plane messages to wirelessly transmit the user data to that UE using that RU, if the RU mask field indicates that the received control-plane message is intended for that RU;
• and
• discarding the received control-plane message and the associated received one or more user-plane messages, if the RU mask field indicates that the received control-plane message is not intended for that RU.

A system comprising:

• a distributed unit (DU) to communicatively couple the system to a core network, the DU configured to implement at least some LAYER 2 functions for a wireless interface and at least some LAYER 1 functions for the wireless interface;
• and
• a plurality of remote units (RUs) to wirelessly transmit and receive radio frequency signals to and from the user equipment using the wireless interface in connection with serving a cell, each of the RUs associated with at least one antenna and located remotely from the DU and at least one other RU, wherein each RU is configured to implement the LAYER 1 functions for the wireless interface that are not implemented in the DU;
• wherein the DU and RUs are communicatively coupled to each other over a fronthaul and are configured to communicate over the fronthaul using an Open Radio Access Network (O-RAN) fronthaul interface;
• and
• wherein the DU and RUs are configured to communicate at least some O-RAN control-plane and user-plane messages that include an O-RAN section extension configured for communicating different section data to different RUs.