Relay Node HARQ Entity Segmentation for LTE Link Reliability
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Solution Overview
Problem
In wireless communication systems with relay nodes, implementing error checking and correction systems is challenging due to issues such as error propagation, variable scheduling delays, and differing radio link conditions between access and relay links, which affect battery life and throughput.
Innovation Solution
Implementing a hybrid automatic repeat request (HARQ) entity on the relay node to handle error detection and correction independently for both access and relay links, allowing for resegmentation and reencoding of data packets based on radio conditions, thereby maintaining efficient resource use and scheduling gain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If error checking and correction systems are implemented in relay nodes, then communication reliability is improved, but device complexity increases
Solution Approach 1:
The patent divides the error checking and correction functionality into separate HARQ entities for different communication links (access link and relay link). Each HARQ entity independently handles error detection and correction for its specific link, segmenting the overall error handling system to manage complexity while maintaining reliability across multiple links.
2Productivity
If HARQ functionality is implemented on relay node, then throughput is improved, but use of energy increases
Solution Approach 1:
The patent applies local quality by implementing HARQ functionality specifically at the relay node to handle error-prone relay link transmissions, while keeping other parts of the system simpler. The relay node performs selective error checking and correction only where needed (on the relay link), optimizing the balance between throughput improvement and energy consumption by not implementing full HARQ functionality everywhere in the system.
3Productivity
If independent HARQ entities are used for access and relay links, then communication efficiency is improved, but device complexity increases
Solution Approach 1:
The patent segments the HARQ functionality into distinct entities for different communication links (access link HARQ entity and relay link HARQ entity). Each entity independently manages error detection and correction for its specific link, allowing optimized error handling per link while maintaining clear separation of functions to manage overall device complexity.
4Adaptability or versatility
If resegmentation and reencoding are performed based on radio conditions, then adaptability is improved, but processing time increases
Solution Approach 1:
The patent implements dynamic resegmentation and reencoding capabilities that adapt to changing radio conditions. The HARQ entities can dynamically adjust packet segmentation and encoding based on current channel quality, allowing the system to optimize performance for varying conditions while managing processing time through efficient adaptive algorithms.
Data Source
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Figure 4A
AI summary
An LTE relay node configured to receive a first MAC PDU, from an LTE eNodeB, and a second MAC PDU, from an LTE UE, the relay node comprising a first HARQ entity configured to perform HARQ functionality with respect to the first MAC PDU and a second HARQ entity configured to perform HARQ functionality with respect to the second MAC PDU. The LTE relay node is further configured to avoid transmitting the first MAC PDU to the LTE UE unless the first MAC PDU is free of errors when received from the LTE eNodeB, and to break apart the first MAC PDU and/or the second MAC PDU to create smaller transport block sizes, TBS, wherein transport block size depends on radio conditions.