Cross-Carrier Scheduling for RF Switching Delay in LTE-Advanced
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Solution Overview
Problem
LTE-Advanced networks face challenges in efficiently managing bandwidth aggregation and resource allocation due to limited RF TX/RX capabilities of user equipment, leading to data loss during component carrier switching.
Innovation Solution
Implementing a cross-carrier scheduling mechanism that includes a switching delay parameter to allow mobile terminals to switch between component carriers without data loss, by pre-configuring the network and user equipment with specific delay values for each carrier, enabling seamless communication across different frequency ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If spectrum aggregation is used to support bandwidths >20 MHz, then system capacity and spectral efficiency are improved, but device complexity and switching overhead increase due to limited RF TX/RX capabilities
Solution Approach 1:
The patent segments the wide bandwidth into multiple component carriers (CCs), each with a maximum bandwidth of 20 MHz. The UE is configured with a subset of these CCs based on its RF capabilities, allowing the system to support aggregate bandwidths >20 MHz while keeping individual carrier processing within device capabilities. This segmentation resolves the contradiction by enabling high system capacity through aggregation without requiring any single device to handle excessive bandwidth simultaneously.
Solution Approach 2:
The network pre-configures the UE with a specific subset of component carriers and provides switching delay information in advance before actual carrier switching is needed. This preliminary configuration allows the UE to prepare for carrier switching without last-minute complexity, reducing real-time processing demands while maintaining the ability to utilize multiple carriers for high system capacity.
2Productivity
If component carrier switching is performed quickly, then spectral efficiency is improved, but data loss occurs due to limited RF switching time
Solution Approach 1:
The network provides switching delay information to the UE in advance, allowing the UE to know beforehand how long the RF circuit will take to switch between component carriers. This advance notice enables the network to schedule data transmissions appropriately, avoiding data loss during switching intervals while maintaining efficient spectral utilization through coordinated carrier switching.
Solution Approach 2:
The patent introduces a buffering mechanism where the network accounts for the switching delay when scheduling transmissions. By cushioning the scheduling decisions to accommodate the known switching time, the system prevents data loss during carrier transitions while minimizing the impact on overall spectral efficiency through optimized resource allocation.
3Speed
If RF switching time is reduced, then communication speed is improved, but data loss increases during mode switching
Solution Approach 1:
The network provides switching delay information to the UE before actual carrier switching occurs. This allows the UE to prepare its RF circuitry in advance, reducing the effective switching time impact on communication speed. Simultaneously, the network can schedule transmissions to avoid the switching interval, preventing data loss while maintaining high communication speeds during active transmission periods.
Data Source
AI summary
According to one embodiment, a communication device is described comprising a communication circuit configured to communicate in a first communication mode using a first frequency range and a receiver configured to receive a switching delay information message indicating a time interval by which start of communication in a second communication mode using a second frequency range should be delayed after a switch from the first communication mode to the second communication mode. The communication circuit is configured to communicate in the second communication mode when the time interval has elapsed since the start of the switching from the first communication mode to the second communication mode.