Gap Period Configuration for NB-IoT Frequency Synchronization
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Solution Overview
Problem
In wireless communication networks, especially for NB-IoT devices, maintaining frequency synchronization during long uplink transmissions is challenging due to the half-duplex constraint and the use of less expensive oscillators, leading to higher collision probabilities and interference, particularly in grant-free access scenarios.
Innovation Solution
The introduction of gap periods within long NB-PUSCH transmissions allows for downlink communication and frequency synchronization, enabling the base unit to transmit configuration messages and control indication messages, which help in managing resource pools and adjusting transmission and gap durations to mitigate collision probabilities and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If NB-IoT devices use less expensive oscillators to reduce cost, then device cost is reduced, but frequency synchronization accuracy deteriorates due to higher drift rates
Solution Approach 1:
The patent introduces periodic gap periods within long NB-PUSCH transmissions, allowing the device to periodically perform frequency synchronization tracking using downlink reference signals during these gaps, thereby maintaining frequency synchronization accuracy without requiring expensive oscillators
Solution Approach 2:
The patent implements a feedback mechanism where the device monitors downlink reference signals during gap periods to detect frequency drift and adjusts its transmission frequency accordingly, enabling continuous frequency synchronization maintenance using low-cost oscillators
2Duration of action of stationary object
If long NB-PUSCH transmissions are used to maintain continuous uplink communication, then transmission continuity is improved, but frequency synchronization accuracy deteriorates due to inability to perform tracking during transmission
Solution Approach 1:
The patent segments long NB-PUSCH transmissions by introducing periodic gap periods within the transmission duration, dividing the continuous transmission into multiple transmission segments separated by synchronization gaps, allowing frequency tracking without breaking overall transmission continuity
Solution Approach 2:
The patent implements periodic gap periods within long NB-PUSCH transmissions at configured intervals, allowing the device to periodically perform frequency synchronization tracking using downlink reference signals while maintaining overall transmission continuity through the segmented structure
3Productivity
If grant-free access is used to reduce latency and simplify scheduling, then access efficiency is improved, but collision probability increases in long transmission scenarios
Solution Approach 1:
The patent introduces dynamic switching capability between grant-free and grant-based access modes, allowing the system to adaptively select the appropriate access type based on current channel conditions and traffic characteristics, thereby reducing collision probability while maintaining access efficiency
Solution Approach 2:
The patent changes the access mode parameter dynamically, switching between grant-free and grant-based access based on collision detection and channel conditions, allowing the system to optimize between access efficiency and collision avoidance
Data Source
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AI summary
Apparatuses, methods, and systems are disclosed for gap period (524, 528, 532, 536) configuration. One apparatus (200) includes a receiver (212) that receives (602) a configuration message. The configuration message includes information that configures one or more gap periods within a transmission period. The apparatus (212) also includes a transmitter (210) that transmits (604) data in the transmission period. The receiver (212) receives (606) a control indication message in the one or more gap periods.