HARQ Process Group Indicator for Cross-Carrier Retransmission Control
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Solution Overview
Problem
Current DCI messaging formats in LTE systems lack the ability to control cross-carrier adaptive retransmissions in multi-carrier systems, making it difficult to distinguish between sub-frames associated with different carriers during uplink transmissions.
Innovation Solution
Introduction of a new DCI format 0 that includes a HARQ Process Group Indicator (HPGI) to explicitly or implicitly identify HARQ process groups, allowing for the identification of a sub-frame and a new carrier for retransmissions, enabling adaptive retransmissions across multiple carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional DCI messaging formats are used in multi-carrier systems, then the system structure remains simple, but the ability to control cross-carrier adaptive retransmissions and distinguish between sub-frames associated with different carriers is lost
Solution Approach 1:
The patent segments the DCI message format into distinct fields, including a new HARQ Process Group Indicator (HPGI) field and carrier identification fields. This segmentation allows the system to independently control and identify different carriers and their associated sub-frames, enabling cross-carrier adaptive retransmissions without creating a monolithic complex structure.
Solution Approach 2:
The patent introduces an additional dimension to the DCI message structure by incorporating carrier identification fields and HPGI fields that operate alongside traditional scheduling fields. This dimensional expansion allows the system to simultaneously manage multiple carriers and their respective HARQ processes within a single messaging framework, resolving the contradiction between versatility and complexity.
2Productivity
If multiple carriers are used for uplink transmissions, then data transmission rates improve, but the ability to identify and manage HARQ processes for each carrier deteriorates
Solution Approach 1:
The patent introduces the HARQ Process Group Indicator (HPGI) as an intermediary element that bridges the gap between multiple carriers and their associated HARQ processes. The HPGI field acts as a mediator that explicitly identifies which carrier a particular HARQ process belongs to, preventing information loss about process identification while enabling high-speed multi-carrier transmissions.
Solution Approach 2:
The patent changes the parameters of the DCI message format by adding explicit carrier identification fields and HPGI fields. These parameter additions ensure that HARQ process information is preserved and correctly associated with specific carriers, maintaining full information integrity while supporting multiple carriers for enhanced data transmission rates.
3Reliability
If cross-carrier adaptive retransmissions are enabled, then transmission reliability improves, but the complexity of distinguishing between sub-frames associated with different carriers increases
Solution Approach 1:
The patent applies preliminary action by pre-defining and explicitly signaling the association between carriers, sub-frames, and HARQ process groups through the HPGI field and carrier identification fields in the DCI message. This preliminary identification structure is established before retransmission occurs, making it straightforward to detect and measure which sub-frame belongs to which carrier, thereby improving reliability without increasing detection difficulty.
Data Source
AI summary
A method and apparatus wherein the method comprises maintaining at least first and second Hybrid Automatic Repeat reQuest (HARQ) Process Groups (HPGs), receiving a downlink control information (DCI) message, using at least one of explicit information and implicit information associated with the DCI message to identify one of the HPGs, using at least one of explicit information and implicit information associated with the DCI message to identify a first carrier and generating a transmission of at least one data packet using the identified HPG to an access device via the carrier and a first uplink sub-frame.