Uplink Transmission Multiplexing eMBB URLLC Latency
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Solution Overview
Problem
In 5G communications, implementing multiplex transmission of eMBB and URLLC services on shared uplink resources is challenging due to increased latency caused by dynamic resource sharing and the inability to pre-configure resources for URLLC services, leading to inefficient frequency band utilization.
Innovation Solution
The method involves dynamic scheduling of uplink transmission, where control information is used to determine time-frequency resources for both grant-based and grant-free services, allowing for overlapping resource usage to improve resource multiplexing and reduce latency by sending no signal or specific reference signals on overlapping resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If dynamic resource sharing is used for uplink transmission, then resource utilization is improved, but latency increases due to SR and UL grant signaling
Solution Approach 1:
The base station pre-configures multiple UL grants with different time-frequency resources and numerologies before URLLC traffic arrives. When URLLC data needs transmission, the UE can immediately use the pre-configured grant without waiting for SR/UL grant signaling, thus reducing latency while maintaining resource utilization through dynamic scheduling of the pre-configured resources
2Loss of time
If grant-free transmission is used for URLLC service, then latency is reduced, but the base station cannot obtain resource occupation information in advance
Solution Approach 1:
The UE sends an indication message to the base station after using a pre-configured UL grant for URLLC transmission. This feedback mechanism allows the base station to obtain resource occupation information in advance, enabling it to perform PI signaling for eMBB resource pre-emption while maintaining the low latency benefits of grant-free transmission
3Loss of time
If pre-configured resources are allocated for URLLC service, then latency is reduced, but frequency band resource utilization becomes extremely low due to sporadic traffic
Solution Approach 1:
The system dynamically selects between pre-configured grants and dynamically scheduled grants based on URLLC traffic conditions. When URLLC traffic is active, pre-configured grants provide low latency; when no URLLC traffic is present, the pre-configured resources can be released or shared with eMBB services, maintaining low latency capability while improving overall resource utilization
4Loss of information
If PI signaling is used for resource pre-emption notification, then eMBB resource occupation can be indicated, but it requires URLLC to be transmitted based on uplink grant which increases latency
Solution Approach 1:
The base station pre-configures multiple UL grants with different numerologies and time-frequency resources before URLLC traffic arrives. When URLLC data needs transmission, the UE can immediately use the pre-configured grant without waiting for SR/UL grant signaling, thus reducing latency while maintaining the ability to perform PI signaling for resource pre-emption
Data Source
AI summary
An uplink transmission method includes obtaining control information useable for uplink transmission with dynamic scheduling, determining based on information about a first time-frequency resource allocated to the uplink transmission and configuration information of a first reference signal useable for the uplink transmission, a second time-frequency resource useable to send the first reference signal, obtaining first information of a semi-statically configured resource useable for the uplink transmission, and in response to performing the uplink transmission based on the control information, sending, by the communications apparatus on an overlapping time-frequency resource of a second time-frequency resource and a third time-frequency resource, a reference signal generated based on configuration information of a second reference signal or failing to send a signal. The control information includes information about the first time-frequency resource allocated to the uplink transmission and configuration information of the first reference signal useable for the uplink transmission.