Nested Carrier Aggregation in Unlicensed Spectrum
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current mobile communications networks face challenges in deploying LTE in unlicensed spectrum due to unpredictable interference and lack of mechanisms to identify channel quality and efficiently use unlicensed frequency bands, leading to difficulties in providing reliable communications resources.
Innovation Solution
The solution involves configuring a mobile communications network to identify and aggregate candidate channels in unlicensed frequency bands into a nested carrier, allowing for the creation of secondary cells that can be managed similarly to licensed frequency bands, thereby enabling efficient use of unlicensed spectrum resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If LTE network operates in unlicensed spectrum, then spectrum utilization is improved, but interference reliability deteriorates
Solution Approach 1:
The unlicensed spectrum is divided into multiple candidate channels, each representing a minimum communication resource unit. The network segments the continuous unlicensed band into discrete selectable channels, allowing flexible aggregation to form nested carriers with desired bandwidth while avoiding heavily interfered channels.
Solution Approach 2:
The nested carrier configuration is dynamic, allowing the network to adjust the number and selection of candidate channels based on real-time interference conditions. The controller can reconfigure nested carriers by selecting different combinations of candidate channels from the predefined set, adapting to changing spectrum conditions.
2Productivity
If candidate channels are aggregated into nested carrier, then throughput is improved, but device complexity increases
Solution Approach 1:
The network pre-configures a set of candidate channels that can be used to form nested carriers. These candidate channels are identified and prepared in advance based on spectrum analysis and interference assessment, so that when data transmission is needed, the controller can quickly select and aggregate appropriate channels without complex real-time analysis.
Solution Approach 2:
The controller acts as an intermediary between the raw unlicensed spectrum resources and the LTE communication layers. It manages the aggregation of candidate channels into nested carriers, handling the complexity of resource management and presenting a simplified interface to upper layers through standard LTE carrier aggregation mechanisms.
3Reliability
If control channels are provided on primary carrier, then control reliability is improved, but frequency resource utilization deteriorates
Solution Approach 1:
The control channels are extracted and placed exclusively on the licensed primary carrier, separating control plane functions from user plane data transmission. This allows the unlicensed nested carriers to be fully utilized for data throughput while the licensed primary carrier provides reliable control signaling.
Data Source
AI summary
A communications device can transmit and receive data via a wireless access interface provided by a mobile communications network including an infrastructure equipment for transmitting signals to or receiving signals from the communications device. The wireless access interface provides a primary carrier within a first frequency range, which forms a primary cell providing a contiguous set of communications resources across the first frequency range and providing one or more control channels for transmitting signaling message to the communications device or receiving signaling messages from the infrastructure equipment. A controller in combination with a receiver and transmitter can receive from the infrastructure equipment a signaling message identifying a nested carrier including one or more candidate channels selected from a predefined plurality of candidate channels within a second frequency range which is different to and mutually exclusive from the first frequency range.