Virtual Carrier for TDD Carrier Aggregation Latency
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Solution Overview
Problem
Current wireless communication systems face challenges in supporting multiple carriers in time division duplex (TDD) systems for ultra-reliable and low latency communications, particularly in achieving efficient carrier aggregation and minimizing latency due to unavailable subframes in TDD systems.
Innovation Solution
The method involves configuring a virtual carrier by shifting one component carrier relative to another in time, allowing communication via either carrier at each time interval, which enables dynamic use of DL and UL resources between carriers, thereby maximizing available time intervals for data transmission and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carrier aggregation is implemented in TDD systems, then system capacity and service availability are improved, but latency increases due to unavailable subframes and complex carrier coordination
Solution Approach 1:
The patent applies dynamics by making the virtual carrier configuration flexible and adaptive. The network dynamically configures the virtual carrier parameters including time shift values, TDD uplink-downlink configurations, and subframe offsets. This allows the system to adapt to changing traffic conditions and minimize latency by selecting optimal carrier combinations and configurations in real-time, resolving the contradiction between reliable service availability and low latency.
Solution Approach 2:
The patent introduces a virtual carrier as an intermediary concept that mediates between multiple physical component carriers. The virtual carrier provides a unified interface for scheduling and resource allocation, while the network can dynamically select which physical carrier to use for actual transmission. This intermediary layer simplifies the complexity of multi-carrier coordination and enables more efficient resource utilization, reducing latency while maintaining service availability.
2Productivity
If multiple component carriers are coordinated for carrier aggregation, then system capacity increases, but device complexity and baseband processing requirements increase
Solution Approach 1:
The patent implements universality by creating a virtual carrier that serves multiple functions: it acts as a logical carrier for scheduling, a reference for resource allocation, and a flexible interface that can map to different physical carriers. The UE only needs to maintain one virtual carrier configuration rather than independently managing multiple physical carriers, reducing baseband processing complexity while still enabling carrier aggregation for increased system capacity.
Solution Approach 2:
The patent uses copying by creating a virtual representation (virtual carrier) of the physical carriers. Instead of requiring the UE to directly handle multiple physical carriers with their individual configurations, the system creates a simplified copy or abstraction layer that represents the aggregated carriers. This virtual carrier copy reduces the processing burden on the UE while maintaining the benefits of multi-carrier operation.
3Device complexity
If TDD uplink-downlink configurations are fixed, then system structure is simplified, but available transmission time intervals are reduced due to guard periods and unavailable subframes
Solution Approach 1:
The patent applies dynamics by enabling flexible and dynamic configuration of TDD uplink-downlink patterns. The network can dynamically adjust the TDD configuration for each virtual carrier and component carrier, changing the locations of guard periods and unavailable subframes based on traffic demands. This allows the system to maximize available transmission time intervals while maintaining a manageable system structure through centralized control.
Solution Approach 2:
The patent utilizes parameter changes by allowing the TDD configuration parameters (such as uplink-downlink assignment, guard period locations, and subframe offsets) to be dynamically modified. The network can change these parameters for different virtual carriers and component carriers to optimize the use of available time intervals. This flexibility increases productivity by maximizing transmission opportunities while keeping the system structure manageable through parameterized control.
Data Source
AI summary
A method and apparatus for communicating with a network in a wireless communication system is provided. A user equipment (UE) receives information on transmission direction of a plurality of time intervals in a first component carrier (CC) and a second CC from the network, and communicates with the network via a virtual carrier, which is either any one of the first CC or the second CC at each of the plurality of time intervals, based on the information. The second CC is shifted in time relative to the first CC by a specific time interval.