Timing Advance Validation for NB-IoT Preconfigured Uplink Resources
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Solution Overview
Problem
Current NB-IoT technologies face challenges in maintaining uplink timing alignment for idle user equipment (UE) that need to transmit data early, as existing timing advance validation procedures are primarily designed for connected UEs and do not effectively support early data transmission in preconfigured uplink resources.
Innovation Solution
The proposed solution involves configuring multiple values for a time alignment timer (TAT) by the network for UEs in idle mode, allowing them to perform early data transmission using preconfigured uplink resources, and extending the uplink timing alignment maintenance procedure to ensure synchronization with the network, even when switching between connected and idle modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing timing advance validation procedures are used for connected UEs, then uplink timing alignment is maintained for connected mode, but idle UEs cannot perform early data transmission with proper timing alignment
Solution Approach 1:
The patent segments the timing alignment maintenance mechanism by introducing mode-specific time alignment timers (TAT_CONNECTED for connected mode, TAT_IDLE for idle mode). Each timer operates independently with its own validation rules, allowing connected and idle UEs to maintain timing alignment through different procedures appropriate to their respective states.
Solution Approach 2:
The patent implements dynamic timing advance validation where the validation behavior changes based on UE mode. In connected mode, traditional validation applies, while in idle mode, a new validation mechanism using preconfigured uplink resources and TAT_IDLE timer is activated. The system dynamically adapts the validation procedure to the current operational state.
2Loss of time
If idle UEs use preconfigured uplink resources for early data transmission, then transmission latency is reduced, but timing alignment maintenance becomes challenging without network connection
Solution Approach 1:
The patent applies preliminary action by preconfiguring uplink resources and pre-establishing timing advance values before the idle UE needs to transmit data. The TAT_IDLE timer is pre-started when the UE enters idle mode with a valid timing advance, allowing the UE to immediately use preconfigured resources without performing random access procedures, thus reducing latency while maintaining timing alignment.
Solution Approach 2:
The idle UE performs self-service timing alignment maintenance by autonomously managing the TAT_IDLE timer and validating its own timing advance against preconfigured parameters. The UE can independently determine whether to use preconfigured uplink resources based on timer status and configuration validity, without requiring real-time network intervention for timing validation.
3Stability of the object's composition
If multiple TAT values are configured for different modes, then timing alignment can be maintained across mode transitions, but configuration complexity increases
Solution Approach 1:
The patent applies local quality by assigning specific TAT values to specific operational modes: TAT_CONNECTED for connected mode and TAT_IDLE for idle mode. Each timer has localized configuration parameters optimized for its specific mode, allowing independent optimization without interfering with the other mode's timing requirements.
Solution Approach 2:
The patent creates a universal timing alignment maintenance framework that handles both connected and idle modes through a unified mechanism. The same fundamental concept of TAT-based validation is applied across modes, with only the specific timer values and validation criteria differing. This multi-functional approach simplifies the overall system architecture compared to implementing entirely separate mechanisms.
Data Source
AI summary
Various examples and schemes pertaining to timing advance validation for transmission in preconfigured uplink resources in narrowband Internet of Things (NB-IoT) are described. When in a first mode, an apparatus (e.g., a user equipment) receives a plurality of different values for a time alignment timer (TAT) from a network before entering a second mode from the first mode. When in the second mode, the apparatus selects one of the plurality of values to apply to the TAT and also starts the TAT to count. When there is data for uplink transmission while the apparatus is still in the second mode, the apparatus performs an early data transmission in an event that a timing advance (TA) value is valid and that the apparatus is in the same serving cell as it was before entering the second mode.