Backhaul Link UL HARQ Process Identification Method
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Solution Overview
Problem
In the LTE and LTE-A systems, the backhaul link's HARQ process identification is limited due to the inability to use specific subframes for data transmission, leading to constraints in the HARQ process and the need for a method to calculate or identify the UL HARQ process ID.
Innovation Solution
A method and device for identifying the UL HARQ process in a backhaul link by calculating the UL or DL subframe number, or using indices of sets composed of UL or DL subframes, employing direct and indirect calculation modes to determine the HARQ process ID, ensuring compatibility and avoiding additional signaling overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If MBSFN subframes are configured for backhaul link, then the relay can receive data from eNode-B, but specific subframes (#0, #4, #5, #9 in FDD or #0, #1, #5,6 in TDD) cannot be allocated as MBSFN subframes due to synchronization and paging requirements
Solution Approach 1:
The patent changes the parameter of subframe allocation by introducing a mapping relationship between unavailable subframes and alternative HARQ process IDs. Instead of allowing direct use of restricted subframes, the system maps these subframes to equivalent HARQ processes through calculation formulas, thereby enabling backhaul transmission while respecting synchronization and paging constraints.
2Device complexity
If HARQ process identification is restricted due to subframe constraints, then system complexity is reduced, but the number of available HARQ processes is limited
Solution Approach 1:
The system implements self-service by enabling the relay node and base station to autonomously calculate HARQ process IDs using predetermined formulas based on subframe numbers. This eliminates the need for complex signaling overhead or external coordination, allowing the system to independently manage HARQ process identification while maximizing process availability within constraints.
3Loss of information
If direct calculation of HARQ process ID is used, then signaling overhead is reduced, but compatibility with existing LTE protocols must be maintained
Solution Approach 1:
The patent achieves universality by designing a HARQ process identification mechanism that works across both FDD and TDD modes, as well as with both normal and extended CP configurations. The calculation formulas are universally applicable to different LTE deployment scenarios, maintaining protocol compatibility while eliminating the need for mode-specific signaling.
Data Source
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AI summary
The disclosure discloses a method and a device for identifying an Uplink (UL) HARQ process of a backhaul link, for solving the problem of identification of the UL HARQ process of the backhaul link. In the disclosure, a base station and a relay node identify the UL HARQ process of the backhaul link according to a UL subframe number of the backhaul link, or a Downlink (DL) subframe number of the backhaul link, or an index of a set composed by UL subframes of the backhaul link, or an index of a set composed by DL subframes of the backhaul link. The disclosure can be applied to the link from a base station to a relay node commendably, not only ensures the backward compatibility, but also solves the problem of identification of the UL HARQ process of the backhaul link, without adding new signalling overhead.