Multi-carrier Grant Design for LTE-A Control Overhead
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Solution Overview
Problem
In wireless communication systems, multi-carrier environments face challenges in distinguishing control information for multiple carriers, leading to increased overhead and inefficient user equipment (UE) assignment monitoring, especially in LTE-A systems where separate HARQ processes and resource assignments for each carrier are costly and complex.
Innovation Solution
The implementation of a method that uses an anchor carrier to communicate resource assignments for multiple carriers, allowing for efficient identification of control information based on operating modes, reducing overhead by using multicarrier grants that share common fields across carriers and enabling flexible data scheduling across multiple carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate control information is used for each carrier, then carrier-specific resource assignment precision is improved, but system overhead increases and device complexity increases
Solution Approach 1:
The patent merges control information for multiple carriers into a single unified grant message transmitted on the anchor carrier. Instead of sending separate control messages for each carrier, the system combines resource assignments for multiple carriers (including non-anchor carriers) into one message, thereby reducing control information overhead while maintaining carrier-specific resource allocation precision through explicit carrier identification fields in the grant message.
Solution Approach 2:
The anchor carrier is designed to serve multiple functions: it transmits control information for itself, transmits control information for other non-anchor carriers, and provides a unified grant message that can schedule resources across multiple carriers. This multi-functional approach allows a single carrier to handle control for the entire multi-carrier system, reducing overall overhead.
2Reliability
If separate HARQ processes are used for each carrier, then data transmission reliability is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent combines HARQ process management across multiple carriers into a unified framework. The single grant message received on the anchor carrier contains resource assignments and HARQ information that apply to multiple carriers, allowing the UE to manage HARQ processes centrally rather than maintaining separate HARQ state machines for each carrier. This reduces device complexity while maintaining reliability through explicit carrier identification in the grant.
3Measurement precision
If control information is transmitted on each carrier, then carrier-specific control accuracy is improved, but system overhead and energy consumption increase
Solution Approach 1:
The patent extracts control information transmission from all carriers and consolidates it to only the anchor carrier. By taking out the control transmission function from non-anchor carriers and centralizing it on the anchor carrier, the system reduces the number of carriers the UE must monitor for control information, thereby reducing energy consumption while maintaining control accuracy through the unified grant message format that explicitly identifies target carriers.
4Reliability
If multiple anchor carriers are used, then control information reliability is improved, but system complexity and overhead increase
Solution Approach 1:
The patent segments the multi-carrier system into a hierarchical structure with one anchor carrier and multiple non-anchor carriers. The anchor carrier is designated as the sole control information transmission point, while non-anchor carriers focus on data transmission. This segmentation eliminates the complexity of managing multiple anchor carriers while maintaining reliability, as the single anchor carrier transmits unified grant messages that schedule resources across all carriers including themselves.
Data Source
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AI summary
Systems and methodologies are described that facilitate assigning resources for an anchor carrier and an additional carrier with a grant message. The grant message communicated with an anchor carrier can include resource information a plurality of carriers. Moreover, the systems and methodologies that facilitate identifying control information for an anchor carrier and/or an additional carrier based upon an operating mode, wherein the operating mode is a legacy mode or an extended mode. Based on the operating mode, particular resources associated with control regions are monitored for control information for respective anchor carrier(s) or additional carrier(s).