NOMA HARQ Data Buffering for Wireless Access Systems
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Solution Overview
Problem
Wireless access systems face challenges in reliably transmitting and receiving data using the Hybrid Automatic Repeat Request (HARQ) method, especially in Non-Orthogonal Multiple Access (NOMA) schemes, where data buffering and acknowledgment management are inefficient, leading to suboptimal performance.
Innovation Solution
A method and apparatus for performing data buffering in a wireless access system supporting NOMA, where a UE receives and decodes multiplexed data from an eNB, buffers data of other UEs, and transmits HARQ-ACK information, with options to buffer data based on Log Likelihood Ratio (LLR) values, signal quality, or decoding success, enhancing data storage and transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If data of multiple UEs are multiplexed and transmitted using NOMA scheme, then spectral efficiency and system capacity are improved, but data buffering and HARQ acknowledgment management become complex and inefficient
Solution Approach 1:
The patent segments the buffering and HARQ management process into distinct components: separating data reception, decoding, buffering decisions, and HARQ-ACK transmission for each UE. This allows independent management of each UE's data flow while maintaining overall system efficiency under NOMA multiplexing.
Solution Approach 2:
The patent performs preliminary actions by buffering data of other UEs before HARQ acknowledgment is required. This advance buffering ensures that when retransmission is needed, the data is already available in memory, reducing latency and improving HARQ efficiency in NOMA systems.
2Reliability
If data of other UE is buffered in memory to support HARQ operation, then HARQ reliability is improved, but memory resources are consumed
Solution Approach 1:
The patent applies local quality by selectively buffering data based on specific conditions rather than uniformly buffering all received data. Buffering decisions are made locally for each UE's data based on decoding outcomes, HARQ process state, and memory availability, optimizing the balance between reliability and resource consumption.
Solution Approach 2:
The patent implements discarding and recovering by clearing buffered data of other UEs when it is successfully decoded or when memory resources are needed for new data. This prevents unnecessary memory consumption while ensuring data is retained only when needed for HARQ retransmission operations.
3Reliability
If selective buffering based on LLR value or signal quality is performed, then transmission reliability is improved, but processing complexity increases
Solution Approach 1:
The patent changes parameters by using LLR values and signal quality metrics as decision criteria for buffering. Instead of simple binary buffering decisions, the system evaluates continuous parameters (LLR magnitude, signal-to-noise ratio) to determine buffering necessity, improving reliability through quality-aware selection while maintaining manageable processing complexity through threshold-based decisions.
Data Source
AI summary
The present invention relates to a variety of hybrid automatic repeat request (HARQ) methods, data buffering methods therefor, and apparatuses supporting the methods, in a wireless access system supporting a non-orthogonal multiple access (NOMA) scheme. As one embodiment of the present invention, a data buffering method, by a first terminal, for hybrid automatic repeat request (HARQ) in a wireless access system supporting a non-orthogonal multiple access (NOMA) scheme may comprise: a step of receiving, from a base station, data in which data for the first terminal and a second terminal are multiplexed in a NOMA scheme; a step of decoding the multiplexed data; a step of buffering data for the second terminal; and a step of transmitting HARQ-ACK information to the base station, depending on the decoding result.