NB-IoT Uplink Subcarrier Bandwidth Selection via Base Station Indication
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Solution Overview
Problem
Current LTE systems face challenges in selecting appropriate subcarrier bandwidths for NB-IoT uplink transmission modes, particularly for NB-PUCCH and NB-PUSCH, due to limited coverage and high penetration losses in machine-to-machine communication scenarios, leading to inefficient data transmission.
Innovation Solution
A method is introduced where a base station generates and sends indication information to user equipment (UE) to select optimal subcarrier bandwidths for single-tone transmission after NB-PRACH transmission, allowing for dynamic selection of subcarrier bandwidths based on available sets and default/predetermined bandwidths for improved uplink transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple subcarrier bandwidth options are provided for NB-IoT uplink transmission, then transmission adaptability to different coverage conditions is improved, but device complexity for selecting and managing multiple bandwidth configurations increases
Solution Approach 1:
The patent applies parameter changes by providing multiple subcarrier bandwidth configurations (3.75 kHz, 15 kHz, and 7.5 kHz) and enabling dynamic selection among them based on coverage conditions. The base station configures different subcarrier bandwidth parameters for NB-PUCCH and NB-PUSCH transmissions, allowing the system to adapt to varying propagation environments without changing the underlying transmission framework.
Solution Approach 2:
The patent implements self-service through automatic subcarrier bandwidth selection mechanisms where the UE autonomously selects appropriate subcarrier bandwidth based on configured parameters and channel conditions. The system enables self-service by allowing UEs to independently determine transmission parameters without requiring manual configuration or complex network control for each transmission instance.
2Productivity
If dynamic subcarrier bandwidth selection is implemented for NB-PUCCH and NB-PUSCH, then data transmission rate and latency are improved, but signaling overhead and configuration complexity increase
Solution Approach 1:
The patent applies preliminary action by pre-configuring subcarrier bandwidth parameters through RRC signaling before actual data transmission. The base station provides UE with a set of configured subcarrier bandwidths and associated parameters in advance, allowing the UE to quickly select appropriate configurations during transmission without requiring real-time signaling exchanges for each transmission decision.
Solution Approach 2:
The patent implements dynamics through flexible subcarrier bandwidth selection that adapts to changing channel conditions. The system transitions from static bandwidth configuration to dynamic selection among multiple pre-configured options, enabling the transmission parameters to be optimized based on current coverage conditions while maintaining efficient signaling through reuse of pre-established configurations.
3Speed
If subcarrier bandwidth is increased for better data transmission, then transmission speed improves, but penetration loss through building structures worsens
Solution Approach 1:
The patent applies parameter changes by providing multiple subcarrier bandwidth options (3.75 kHz, 7.5 kHz, 15 kHz) that enable trading off between transmission speed and penetration capability. Lower subcarrier bandwidths (3.75 kHz) provide better penetration through building structures and are suitable for coverage-enhanced scenarios, while higher bandwidths (15 kHz) offer faster transmission in areas with good signal conditions. The system dynamically selects appropriate parameters based on measured channel quality and coverage requirements.
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AI summary
The present invention provides a method of indicating a subcarrier bandwidth for uplink transmission, executed by a base station, the method comprising: generating indication information, the indication information being used to indicate a subcarrier bandwidth for single-tone transmission in a first NB-PUSCH and/or a second NB-PUSCH after NB-PRACH transmission; and sending to a user equipment (UE) the generated indication information to indicate to the UE a subcarrier bandwidth for the single-tone transmission. Accordingly, the present invention further provides a method of selecting a subcarrier bandwidth for uplink transmission executed by a UE, and a base station and a UE respectively executing the above methods.