NOMA Uplink Detection via Repeated Pilot Activation
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Solution Overview
Problem
In 5G mobile communication systems, the existing uplink scheduling algorithms for IoT applications with a large number of connections face challenges in managing high reliability and low time delay, leading to significant control signaling overhead and limited scheduled users due to resource constraints, especially when terminals employ a scheduling-free access mechanism, making it difficult for base stations to perform uplink detection.
Innovation Solution
The proposed method involves pilot activation detection and channel estimation in a non-orthogonal multiple access (NOMA) system, where the base station repeatedly performs pilot activation detection on terminals until a detection end condition is met, determining actual access terminals and decoding data channels based on channel estimation results, thereby reducing error probability and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a scheduling-free access mechanism is used to support a large number of connections, then the number of supported connections increases, but the base station cannot determine transmission time and position of uplink pilot, making uplink detection difficult
Solution Approach 1:
The base station pre-configures multiple possible transmission time positions for uplink pilots and repeatedly performs pilot activation detection at these predetermined positions. This preliminary setup allows the system to handle scheduling-free access by having detection ready at all possible positions before actual transmission occurs.
Solution Approach 2:
Terminals autonomously select transmission time positions from pre-configured options without base station scheduling, and the base station autonomously performs repeated pilot activation detection at all possible positions. This self-service mechanism enables both parties to operate independently while maintaining detection capability.
2Reliability
If traditional uplink scheduling algorithm is used for IoT applications with large number of connections, then uplink detection can be performed, but control signaling overhead becomes significant and number of scheduled users is limited by control channel resources
Solution Approach 1:
The invention extracts the scheduling function from the uplink access mechanism, removing the need for control signaling while retaining detection capability. By separating pilot activation detection from scheduled resource allocation, the system eliminates control overhead for granting resources while maintaining reliable detection through repeated attempts at pre-configured positions.
Solution Approach 2:
The repeated pilot activation detection mechanism serves multiple functions: it detects active terminals, determines transmission positions, and handles both scheduled and unscheduled access scenarios. This multi-functional approach replaces the need for separate control signaling for resource allocation and detection.
3Measurement precision
If pilot activation detection is performed repeatedly to determine actual access terminals, then detection accuracy improves, but detection time and processing complexity increase
Solution Approach 1:
The system performs pilot activation detection periodically at pre-configured time positions rather than continuously. By repeating detection at specific intervals and positions, the system achieves high accuracy while limiting total detection time through the periodic rather than continuous approach.
Data Source
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AI summary
The present disclosure discloses an uplink detection method and device in a NOMA system. The method includes: performing pilot activation detection on each terminal in a first terminal set corresponding to a NOMA transmission unit block repeatedly until a detection end condition is met, wherein the first terminal set includes terminals that may transmit uplink data on the NOMA transmission unit block; performing channel estimation on each terminal in a second terminal set that determined through the pilot activation detection within each repetition period, wherein the second terminal set includes terminals that have actually transmitted uplink data on the NOMA transmission unit block; and detecting and decoding a data channel of each terminal in the second terminal set within each repetition period. In the technical solution provided by the embodiment of the present disclosure, a probability of error of the pilot activation detection and data detection at the base station side is reduced effectively, and the accuracy of the pilot activation detection and the data detection is improved.