HARQ Mapping for Carrier Aggregation in Wireless Networks
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Solution Overview
Problem
Wireless networks face congestion due to increased data transmission demands, particularly in high-density areas, leading to bandwidth limitations in licensed spectrum usage.
Innovation Solution
Carrier aggregation technology is employed to form virtual wideband channels by combining multiple smaller bandwidths, allowing for explicit mapping of Hybrid Automatic Retransmission Request (HARQ) for Carrier Aggregation at User Equipment (UE), enabling efficient bandwidth utilization across multiple component carriers with different uplink-downlink configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If carrier aggregation is used to combine multiple component carriers, then bandwidth utilization and data throughput are improved, but system complexity and resource allocation difficulty increase
Solution Approach 1:
The patent segments the HARQ-ACK feedback resources by creating separate PUCCH resource pools for different component carriers. Each component carrier is assigned specific PUCCH resources, allowing independent management and reducing the complexity of coordinating HARQ feedback across aggregated carriers. This segmentation enables the system to handle multiple carriers without proportionally increasing overall system complexity.
Solution Approach 2:
The patent introduces a new dimension for resource management by implementing cross-carrier scheduling where PUCCH resources on one carrier can be used to feedback HARQ-ACK for data transmitted on different carriers. This dimensional approach to resource allocation allows the system to efficiently manage bandwidth across multiple carriers without linearly increasing control channel complexity.
2Reliability
If multiple PUCCH resources are allocated for HARQ-ACK feedback across different component carriers, then acknowledgment reliability is improved, but resource allocation complexity and signaling overhead increase
Solution Approach 1:
The patent implements universal PUCCH resource allocation where a set of PUCCH resources configured on a serving cell can serve multiple component carriers. Instead of dedicating separate PUCCH resources to each carrier, the same PUCCH resources perform the multi-function of carrying HARQ-ACK feedback for multiple carriers, thereby maintaining reliability while reducing allocation complexity and signaling overhead.
Solution Approach 2:
The patent merges the HARQ-ACK feedback mechanisms of multiple component carriers into a unified resource allocation framework. By combining the resource management of different carriers into a single coordinated system, the patent reduces the overall complexity of tracking and allocating PUCCH resources while ensuring that each carrier's feedback requirements are met reliably.
3Productivity
If explicit mapping of HARQ for carrier aggregation is implemented, then bandwidth allocation efficiency is improved, but processing complexity at User Equipment increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring PUCCH resource mappings and HARQ-ACK feedback associations through higher-layer signaling before data transmission begins. This advance configuration allows the User Equipment to efficiently process bandwidth allocation without real-time computation complexity, as the mapping relationships are established beforehand and can be quickly referenced during actual data transmission and feedback.
Data Source
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AI summary
Technology to support mapping for Hybrid Automatic Retransmission re-Quest (HARQ) for Carrier Aggregation (CA) is disclosed. One method can include a user equipment (UE) identifying, within a radio frame, a type 2 DownLink (DL) sub-frame within a virtual bundling window associated with a Secondary Component Carrier (SCC). The type 2 DL sub-frame can be virtually moved from a Primary Component Carrier (PCC) for HARQ-ACKnowledge (HARQ-ACK) multiplexing of the virtual bundling window. The UE can extract a Component Carrier Element (CCE) number for a first CCE used by a Physical Downlink Control CHannel (PDCCH) transmission corresponding to the type 2 DL sub-frame. The UE can determine a Physical Uplink Control CHannel (PUCCH) resource for carrying a HARQ-ACK multiplexing message based on the CCE number when a PCC window size of the PCC is greater than an SCC window size of the SCC.