Joint HARQ Process Identity for Multi-Carrier Wireless
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Solution Overview
Problem
Current wireless communication systems using Dual-Cell HSDPA face challenges in efficiently utilizing supplementary carriers during low utilization periods and in signaling HARQ processes across multiple carriers, leading to potential data loss and increased latency.
Innovation Solution
Implementing joint HARQ processes that allow transmissions and retransmissions to occur on multiple carriers, with mechanisms to determine and signal the HARQ process identity using additional information, enabling effective utilization of supplementary carriers and improving system performance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate HARQ entities are used for each carrier, then implementation is simpler and carrier-specific control is improved, but resource utilization efficiency deteriorates and data transmission flexibility is reduced
Solution Approach 1:
The patent merges HARQ entities across multiple carriers by introducing a joint HARQ entity that manages HARQ processes for both anchor and supplementary carriers. This allows retransmissions to occur on any available carrier, improving resource utilization efficiency while maintaining implementation feasibility through a unified management approach.
Solution Approach 2:
The joint HARQ entity provides multi-functionality by managing HARQ processes for multiple carriers simultaneously. The same HARQ entity can handle transmissions on the anchor carrier, supplementary carrier, or both, enabling flexible resource allocation and improving overall system productivity without sacrificing ease of implementation.
2Productivity
If joint HARQ processes are implemented across multiple carriers, then resource utilization and flexibility are improved, but signaling complexity and identity determination difficulty increase
Solution Approach 1:
The patent segments the HARQ process identity into multiple parts: a first part indicating the carrier identity (anchor or supplementary) and a second part indicating the specific HARQ process number within that carrier. This segmentation simplifies signaling by breaking down the complex joint HARQ identity into manageable components that can be transmitted and processed separately.
Solution Approach 2:
The patent introduces an intermediary mechanism in the form of a mapping table or indicator field that translates between the segmented HARQ identity parts and the actual joint HARQ process. This intermediary simplifies the signaling complexity by providing a structured way to represent joint HARQ identities without requiring complex direct signaling of all possible carrier-process combinations.
3Productivity
If supplementary carriers are actively utilized during low utilization periods, then system capacity and throughput are improved, but interference management and signal quality maintenance become more difficult
Solution Approach 1:
The patent implements dynamic carrier selection where the supplementary carrier is actively utilized during low utilization periods and can be dynamically activated or deactivated based on traffic conditions and channel quality. This dynamic approach allows the system to improve capacity when conditions are favorable while maintaining the ability to reduce interference management complexity when conditions deteriorate.
Solution Approach 2:
The patent changes the operational parameters of the supplementary carrier based on system conditions, including activation/deactivation states, power levels, and modulation schemes. By adjusting these parameters dynamically, the system can utilize the supplementary carrier for improved capacity during low utilization periods while managing interference through parameter optimization when signal quality becomes a concern.
Data Source
AI summary
Methods and apparatus utilize hybrid automatic repeat request (HARQ) transmissions and retransmissions that are usable on multiple carriers, i.e. joint HARQ processes. For example, a downlink (DL) shared channel transmission of a joint HARQ process is received on one of the carriers. A first part of an identity of the joint HARQ process is determined by using HARQ process identity data received on a shared control channel. A second part of the joint HARQ process identity is determined using additional information. The joint HARQ process identity is then determined by combining the first part and the second part. A WTRU is provided that is configured to receive the DL shared channel and to make the aforementioned determinations. A variety of other methods and apparatus configurations are disclosed for utilizing joint HARQ processes, in particular in the context of DC-HSDPA.