Uplink Timing via Secondary Cell Activation
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Solution Overview
Problem
Current multicarrier communication systems face challenges in efficiently managing signal timing and resource allocation across multiple carriers, particularly in scenarios involving carrier aggregation and dual connectivity, which can lead to increased PUCCH load on primary cells and synchronization issues in unlicensed spectrum usage.
Innovation Solution
The implementation of advanced timing advance group (TAG) configurations and listen-before-talk (LBT) mechanisms enables efficient signal timing alignment and resource management across multiple carriers, including the use of licensed and unlicensed bands, by dynamically adjusting energy detection thresholds and employing adaptive LBT procedures to optimize channel access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation and dual connectivity are implemented to increase data capacity, then system throughput is improved, but PUCCH load on primary cells increases and synchronization issues occur in unlicensed spectrum
Solution Approach 1:
The patent segments the timing advance management by introducing separate TAG (Timing Advance Group) configurations for different cell groups. Primary TAG (pTAG) manages primary cell timing while secondary TAG (sTAG) manages secondary cell timing independently. This segmentation allows independent optimization of PUCCH timing for each cell group, reducing the overall PUCCH load on primary cells while maintaining high throughput from carrier aggregation and dual connectivity.
2Productivity
If multiple carriers are aggregated to support high data rates, then data capacity is improved, but signal timing alignment becomes more difficult across carriers
Solution Approach 1:
The patent introduces an intermediary timing advance mechanism where a timing advance command is transmitted via downlink signaling to the wireless device. This intermediary command acts as a mediator to coordinate the timing alignment across multiple aggregated carriers. The wireless device applies the received timing advance value to align uplink transmissions on all carriers, ensuring precise timing alignment despite the complexity of multi-carrier aggregation.
3Productivity
If unlicensed spectrum is used to increase available bandwidth, then system capacity is improved, but synchronization issues and channel access conflicts arise
Solution Approach 1:
The patent implements preliminary Listen-Before-Talk (LBT) procedures before transmitting on unlicensed carriers. The system performs clear channel assessment and LBT checks in advance to ensure the channel is free before initiating transmission. This preliminary action prevents channel access conflicts and ensures reliable synchronization on unlicensed spectrum, allowing the system to safely utilize additional unlicensed bandwidth to increase overall system capacity.
Data Source
AI summary
A wireless device receives configuration parameters of timing advance groups (TAGs) comprising: a primary TAG comprising a primary cell; and a secondary TAG comprising one or more licensed secondary cells and one or more unlicensed secondary cells. Uplink signals are transmitted via the secondary TAG. The transmission timing is derived employing a first secondary cell, of the secondary TAG, that is based on the first secondary cell being: an activated secondary cell; and a licensed secondary cell.