Uplink Scheduling Conditional Grant ECCA LAA
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Solution Overview
Problem
In wireless communication systems, especially in License Assisted Access (LAA) mode, existing uplink scheduling methods are inadequate for handling heavy traffic and short transmission opportunities in contention-based shared carriers, leading to issues with channel security and synchronization, particularly when multiple nodes contend for access to unlicensed radio frequency spectrum.
Innovation Solution
The proposed solution involves a method where a UE receives a conditional uplink grant with a transmission configuration, allowing for a grant timeline greater than or equal to n+4, and an uplink activation grant is sent over a contention-based shared carrier, enabling secure channel access and synchronization by performing an Extended Clear Channel Assessment (ECCA) to secure the channel, allowing for flexible and efficient uplink transmission scheduling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional uplink scheduling methods are used in LAA mode, then channel access is simplified, but uplink throughput is insufficient and channel security is compromised under heavy traffic conditions
Solution Approach 1:
The base station performs an Extended Clear Channel Assessment (ECCA) procedure before transmitting the uplink activation grant to the UE. This preliminary channel assessment ensures that the uplink transmission opportunity is secure and free from interference before scheduling the uplink transmission, thereby maintaining channel security while enabling efficient uplink throughput in heavy traffic conditions
2Loss of time
If uplink transmission is scheduled immediately after grant reception, then latency is reduced, but synchronization and channel access security are compromised
Solution Approach 1:
The base station transmits the uplink activation grant to the UE before the actual uplink transmission opportunity. This advance scheduling allows the UE to prepare for synchronized transmission while the base station performs the ECCA procedure to ensure channel security. The timing relationship between grant reception and transmission is carefully managed to maintain synchronization without excessive latency
Solution Approach 2:
The uplink activation grant serves as a feedback mechanism from the base station to the UE, confirming that the uplink transmission opportunity has been securely assessed and scheduled. This feedback ensures that the UE can transmit at the correct time with proper synchronization while the base station maintains control over channel access security
3Productivity
If multiple UEs contend for channel access simultaneously, then channel utilization increases, but channel security and access control become compromised
Solution Approach 1:
The base station performs the ECCA procedure before scheduling any uplink transmission, establishing channel security in advance. This preliminary action ensures that when multiple UEs are scheduled for uplink transmission, the channel is already secured against interference, allowing high channel utilization while maintaining security through controlled, scheduled access rather than simultaneous contention
Data Source
AI summary
Uplink scheduling for license assisted access (LAA) mode systems is discussed in which a user equipment (UE) receives a conditional grant from a serving base station that includes a transmission configuration for an uplink transmission. The UE also receives an uplink activation grant over a contention-based shared carrier. The uplink activation grant activates the uplink transmission associated with the conditional grant. Thereafter, the UE transmits the uplink transmission over the contention-based shared carrier according to the transmission configuration.