Centralized Unit PDCP Header Handling for MBMS Multicast Transmission
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Solution Overview
Problem
The New Radio (NR) system lacks a solution for processing and sending Multimedia Broadcast Multicast Service (MBMS) data packets, which is essential for supporting multimedia broadcast services in a broadcast form, unlike previous systems like LTE that use multicast/broadcast single frequency network (MBSFN) transmission methods.
Innovation Solution
The proposed solution involves a communication system architecture where a centralized unit (CU) receives MBMS data packets, generates PDCP data units by adding a PDCP header, and sends them to a distributed unit (DU), which then generates MAC data units for transmission to terminals, allowing for accurate determination of PDCP header length and synchronization protocol header handling to support efficient MBMS data packet processing and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the CU generates PDCP data units by adding PDCP headers and sends them to the DU for MBMS transmission, then the MBMS data packet processing efficiency is improved, but the device complexity increases due to the need for coordination between CU and DU units
Solution Approach 1:
The base station is divided into a centralized unit (CU) and a distributed unit (DU) with distinct functions. The CU handles PDCP layer operations including adding PDCP headers to MBMS data packets, while the DU handles MAC layer operations including generating MAC data units and transmitting signals. This segmentation allows each unit to specialize in specific processing tasks, improving overall MBMS data packet processing efficiency while distributing the complexity across multiple units.
2Measurement precision
If the DU determines PDCP header length based on PDCP format information from the CU, then the synchronization protocol header handling accuracy is improved, but the signaling interworking between CU and DU increases
Solution Approach 1:
The CU performs preliminary processing by adding PDCP headers to MBMS data packets and determining the PDCP header length based on PDCP format information before sending the data to the DU. This preliminary action allows the DU to accurately determine the PDCP header length without requiring complex real-time signaling, as the necessary information is prepared in advance by the CU.
Solution Approach 2:
PDCP format information acts as an intermediary mechanism between the CU and DU. The CU generates this format information containing PDCP header length details and transmits it to the DU along with the MBMS data packets. This intermediary structure enables accurate synchronization protocol header handling at the DU while minimizing the need for additional signaling interworking.
3Stability of the object's composition
If time stamps are added to MBMS data packets for synchronized transmission across multiple eNBs, then the transmission synchronization is improved, but the device complexity increases due to additional processing requirements
Solution Approach 1:
The time stamping function is merged into the PDCP layer processing at the CU. When the CU adds PDCP headers to MBMS data packets, it simultaneously incorporates or associates time stamp information. This merging of functions allows multiple eNBs to achieve transmission synchronization without requiring separate time stamp processing mechanisms, thereby reducing overall device complexity while maintaining stable synchronized transmission.
Data Source
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AI summary
This application provides a communication method, apparatus, and system. The communication method includes: A centralized unit receives a data packet sent in a multicast manner. The centralized unit generates a PDCP data unit based on the data packet, where the PDCP data unit includes the data packet and a PDCP header. The centralized unit sends the PDCP data unit to a distributed unit. The distributed unit receives the PDCP data unit from the centralized unit, where the PDCP data unit includes the PDCP header, a synchronization protocol header, and a payload. The distributed unit generates a MAC data unit, where the MAC data unit includes a MAC header, an RLC header, the PDCP header, and the payload. The distributed unit sends the MAC data unit to a terminal. According to the foregoing method in this application, the data packet sent in the multicast manner can be processed, to support sending of a multimedia broadcast service in a broadcast form, and improve processing performance of the multimedia broadcast service.