Narrowband TDD Frame Structure With Dynamic Subframe Switching
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Solution Overview
Problem
Narrowband communications, such as NB-IoT and eMTC, face challenges in ensuring reliable transmission to challenging locations due to increased chances of improper reception, necessitating support for a narrowband TDD frame structure.
Innovation Solution
The implementation of NPDCCH, NPDSCH, NPUCCH, and NPUSCH transmissions using a narrowband TDD frame structure, which includes configurations determined by higher layer signaling or channel conditions, with flexible subframes and switching periodicities to enhance communication reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If narrowband communications are used to reach challenging locations, then coverage is improved, but transmission reliability deteriorates due to increased chances of improper reception
Solution Approach 1:
The patent implements dynamic TDD frame structures where subframe configurations can be flexibly adjusted based on channel conditions. The system supports multiple TDD configurations that can be switched dynamically to optimize both coverage and reliability for different transmission scenarios, allowing the network to adapt to varying channel quality in challenging locations.
Solution Approach 2:
The patent changes key transmission parameters including subframe length, switching periodicity, and frame structure configuration to improve transmission reliability. By allowing variable subframe configurations and adjusting these parameters based on channel conditions, the system maintains reliable communication while extending coverage to challenging locations.
2Reliability
If predetermined number of repeated transmissions are used to increase decoding chance, then transmission reliability is improved, but use of energy increases
Solution Approach 1:
The patent employs a selective repetition strategy where the number of repeated transmissions is adjusted based on channel conditions and transmission requirements. Instead of always using the maximum number of repetitions, the system applies partial repetitions only when necessary, thereby maintaining reliability while reducing unnecessary energy consumption.
Solution Approach 2:
The system dynamically adjusts the number of repeated transmissions based on channel quality feedback and transmission success probability. When channel conditions are good, fewer repetitions are used; when conditions deteriorate, the system increases repetitions accordingly, optimizing the trade-off between reliability and energy consumption.
3Device complexity
If narrowband communications are used, then device complexity is reduced, but transmission reliability deteriorates in challenging locations
Solution Approach 1:
The patent segments the narrowband transmission into multiple configurable subframes with different functions (downlink, uplink, special subframes). This segmentation allows the system to maintain simple narrowband device architecture while improving reliability through diverse transmission opportunities and flexible resource allocation across multiple subframes.
Solution Approach 2:
The TDD frame structure implements multi-functional subframes that can serve different purposes (data transmission, control signaling, random access) within the same narrowband framework. This universality allows simple narrowband devices to benefit from enhanced reliability through multiple transmission modes and functions without increasing device complexity.
Data Source
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AI summary
There is a need to support narrowband TDD frame structure for narrowband communications. The present disclosure provides a solution by supporting one or more narrowband TDD frame structure(s) for narrowband communications. In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may receive information associated with a narrowband TDD frame structure for narrowband communications. The apparatus may transmit a first symbol group of a first narrowband physical random access channel (NPRACH) preamble to a base station. In one aspect, a first length of the first symbol group may be associated with the narrowband TDD frame structure.