Uplink Resource Release for Small Data Transmission in Inactive State
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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 transmissions with a radio access network (RAN) without transitioning to the RRC_CONNECTED state.
Innovation Solution
A method for resource management in a UE, involving receiving resources for uplink transmission from a RAN in a first cell, initiating a procedure to resume the radio connection with the RAN in a second cell, and releasing the resource in response to the initiation. This method allows for small data transmission (SDT) procedures without full connection establishment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE transitions to RRC_CONNECTED state for data transmission, then reliable data transmission is ensured, but transition time and latency increase
Solution Approach 1:
The patent segments the connection establishment process by introducing an intermediate RRC_INACTIVE state that retains partial connection context. This allows the UE to transmit small data packets without completing full RRC connection establishment, thereby reducing transition time while maintaining sufficient reliability for small data transmissions.
Solution Approach 2:
The network performs preliminary actions by pre-configuring SDT resources and maintaining UE context in the RRC_INACTIVE state before actual data transmission occurs. This preliminary preparation enables faster data transmission without requiring full connection establishment at the moment of data arrival.
2Speed
If the UE maintains RRC_CONNECTED state for quick data transmission, then transmission speed improves, but energy consumption increases
Solution Approach 1:
The patent implements dynamic state management where the UE can transition between RRC_IDLE, RRC_INACTIVE, and RRC_CONNECTED states based on data transmission requirements. The RRC_INACTIVE state provides a dynamic intermediate option that consumes less energy than continuous CONNECTED state while enabling faster transmission than IDLE state.
Solution Approach 2:
The network changes key connection parameters by maintaining partial context (such as security context and bearer configuration) in the RRC_INACTIVE state, allowing the UE to resume transmissions quickly without full re-establishment, thereby reducing energy consumption compared to maintaining full CONNECTED state.
3Loss of energy
If the UE releases uplink resources when moving to inactive state, then resource efficiency improves, but resource re-acquisition time increases
Solution Approach 1:
The patent implements a selective resource management strategy where the network releases certain resources (such as dedicated uplink grants) when transitioning to RRC_INACTIVE state to improve resource efficiency, while simultaneously retaining critical context information that enables rapid resource re-acquisition through SDT procedures.
Solution Approach 2:
The network performs preliminary configuration of SDT-specific resources and maintains essential UE context before the UE transitions to RRC_INACTIVE state. This preliminary action ensures that when the UE needs to transmit data, resources are already prepared or can be quickly allocated without full re-acquisition delays.
Data Source
AI summary
A user equipment (UE) 102 receives, from a radio access network (RAN) 105 and in a first cell 124, a resource for an uplink transmission to the RAN 105 when a radio connection between the UE 102 and the RAN 105 is suspended (e.g., event 1102); initiates, in a second cell 126 and the radio connection is suspended, a procedure to resume the radio connection with the RAN 105 (e.g., event 1106); and in response to the initiating, release the resource (e.g., event 1108).