Retransmission Control for 5G Low Latency
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Solution Overview
Problem
5G mobile communication systems face stringent delay requirements while maintaining high-quality radio transmission, and existing retransmission control methods increase processing delays, making it difficult to achieve both low latency and low error rates.
Innovation Solution
A retransmission control method that performs initial signal detection without frequency domain equalization, followed by a second detection with equalization, allowing for earlier retransmission requests and reduced overall delay times while ensuring error rate quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If frequency domain equalization processing is performed to improve error rate, then reliability is improved, but processing delay increases
Solution Approach 1:
The patent segments signal detection into two distinct phases: initial signal detection without frequency domain equalization (fast processing) and subsequent signal detection with frequency domain equalization (high reliability). This segmentation allows the system to achieve both low latency and low error rates by performing different types of detection at different stages.
Solution Approach 2:
The patent performs preliminary signal detection before frequency domain equalization processing. The initial signal detection is performed on the received signal without waiting for the complete FFT processing, allowing early identification of signals that clearly do not require retransmission, thereby reducing overall processing delay while maintaining error rate performance.
2Reliability
If retransmission control is implemented to reduce error rates, then reliability is improved, but delay time increases
Solution Approach 1:
The patent dynamically adjusts the detection strategy based on signal conditions. The receiving station performs initial signal detection with a first threshold, and only when this initial detection is inconclusive or indicates potential errors does it proceed to more thorough detection with frequency domain equalization. This dynamic approach optimizes the balance between reliability and delay time.
Solution Approach 2:
The patent changes detection parameters (thresholds, processing depth) based on the stage of reception. Initial detection uses a first threshold and no frequency domain equalization, while subsequent detection uses a second threshold and includes frequency domain equalization. This parameter adjustment allows the system to achieve high reliability without always incurring the full processing delay cost.
3Speed
If single carrier transmission is used to reduce processing delay, then speed is improved, but error rate performance deteriorates
Solution Approach 1:
The patent segments the reception process into initial detection (fast, single-carrier-like performance) and subsequent detection (slower, higher reliability). This allows single carrier transmission to maintain its speed advantage while providing an option for enhanced error rate performance when needed, effectively combining the benefits of both approaches.
Solution Approach 2:
The patent applies frequency domain equalization selectively rather than universally. For signals that are clearly detectable in the initial phase, full frequency domain equalization is not applied, maintaining fast processing. For signals that benefit from equalization, the patent applies it in the subsequent detection phase, achieving partial application that optimizes both speed and reliability.
Data Source
AI summary
A receiving station performs first signal detection processing on a received radio signal, performs a retransmission request to a transmitting station in a case in which a code error is detected in a detected radio packet for user data, and enqueues the radio packet in a reception buffer in a case in which no code error is detected. In parallel with the first signal detection processing, the receiving station performs second signal detection processing on the received signal with a longer processing delay than that of the first signal detection processing, and in a case in which no code error is detected in the detected radio packet for user data, the receiving station enqueues the radio packet in the reception buffer. The receiving station outputs, at a predetermined timing, the radio packet for user data with no code error detected, the radio packet being enqueued in the reception buffer.