Inactive State Uplink Transmission via Configured Grants
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Solution Overview
Problem
In wireless communications, user equipment (UE) operating in an inactive or idle state faces challenges in efficiently managing uplink and downlink data transmission with a radio access network (RAN) without transitioning to the RRC_CONNECTED state.
Innovation Solution
The UE receives a configuration for uplink transmission from the RAN when the radio connection is suspended, detects available messages, and refrains from transmitting until an uplink resource becomes available, implementing a method to manage resources and optimize data transmission in the inactive state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE transitions to RRC_CONNECTED state for data transmission, then data transmission reliability is improved, but connection establishment time increases
Solution Approach 1:
The network pre-configures uplink resources (configured grants) for the UE while it is in RRC_INACTIVE state, so that when data arrives, the UE can immediately transmit without needing to establish a connection first. This preliminary preparation of transmission resources resolves the contradiction by having the connection readiness prepared in advance.
Solution Approach 2:
The patent segments the data transmission process into two parts: (1) small data transmission using pre-configured resources in inactive state, and (2) full connection establishment for larger or subsequent data transmissions. This segmentation allows immediate transmission of small packets without the overhead of full connection setup.
2Loss of time
If the UE transmits data immediately when available in inactive state, then latency is reduced, but resource availability conflicts increase
Solution Approach 1:
The patent implements dynamic resource allocation where the network can update and reconfigure uplink resources for the UE in inactive state through RRC reconfiguration messages. This dynamic adjustment allows the system to adapt resource availability to changing conditions while maintaining the ability for immediate transmission.
Solution Approach 2:
The network monitors the usage of pre-configured uplink resources and provides feedback through downlink assignments and reconfiguration messages, adjusting resource allocation based on actual transmission needs and availability, thereby managing resource conflicts dynamically.
3Ease of operation
If the UE maintains configured grant resources in inactive state, then uplink transmission capability is improved, but resource waste increases when resources remain unused
Solution Approach 1:
The patent employs periodic monitoring and periodic reconfiguration of configured grant resources. The network periodically checks whether the UE still needs these resources and periodically updates or releases them, ensuring that resources are maintained only when needed and released when not used, thus reducing waste while preserving capability.
Solution Approach 2:
The network dynamically changes parameters of the configured grants (such as periodicity, resource allocation, validity duration) based on UE activity patterns. When the UE is inactive for extended periods, the network reduces or releases the configured grant resources, adapting the resource level to actual needs.
Data Source
AI summary
A user equipment (UE) 102 receives, from a radio access network (RAN) 105, a configuration for uplink transmission to the RAN 105 when a radio connection between the UE 102 and a radio access network (RAN) 105 is suspended (e.g., event 602); detects, at a first time when the radio connection is suspended, that a message for transmitting to the RAN 105 is available (e.g., event 604); and refrains, at the first time in response to determining that an uplink (UE) resource corresponding to the configuration is not available until a second time subsequent to the first time, from transmitting the message to the RAN 105 (e.g., event 608).