Narrowband TDD Frame Structure for Reliable Deep-Building Coverage
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Solution Overview
Problem
There is a need for improved narrowband time-division duplex (TDD) frame structures to support narrowband communications, particularly in challenging environments where transmissions may not be properly received, such as deep inside buildings, to enhance the reliability of communications in devices like smart gas meters.
Innovation Solution
A mechanism is provided to support narrowband TDD frame structures by determining and transmitting narrowband physical downlink channels, allocating resources, and using UE-specific beamforming to improve signal reception in narrowband communications systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If narrowband communications are used to reach challenging locations (e.g., deep inside buildings), then coverage is extended, but transmission reliability deteriorates due to increased chance of improper reception
Solution Approach 1:
The patent implements repeated transmissions of the same narrowband physical downlink channel across multiple subframes. The base station transmits the channel repeatedly with periodic intervals, allowing the receiver to combine multiple transmissions and improve decoding reliability in challenging coverage areas.
Solution Approach 2:
The patent determines the subframe type (special or downlink) in advance before transmitting the narrowband physical downlink channel. This preliminary determination allows proper configuration of transmission parameters and ensures the transmission occurs in an appropriate subframe type, improving overall transmission reliability.
2Reliability
If repeated transmissions are used to increase decoding probability, then transmission reliability is improved, but transmission time increases
Solution Approach 1:
The patent utilizes contiguous downlink subframes in the narrowband TDD frame structure to perform repeated transmissions without interruption. By having multiple consecutive subframes available for downlink transmission, the system maintains continuous useful action rather than interspersing uplink subframes, thereby reducing total transmission time while maintaining reliability.
Solution Approach 2:
The repeated transmissions are performed periodically across multiple subframes with optimized intervals. The periodic repetition allows the receiver to accumulate signal energy over time while the optimized period minimizes the total time required to achieve reliable decoding.
3Reliability
If narrowband TDD frame structure is used to support repeated transmissions, then transmission reliability is improved, but frame structure complexity increases
Solution Approach 1:
The narrowband TDD frame structure is designed to serve multiple functions: it supports repeated transmissions for reliability, accommodates both special and downlink subframes for flexibility, and enables contiguous subframe allocation for efficient resource utilization. This multi-functionality reduces the need for separate specialized structures, thereby managing complexity while achieving reliability goals.
Solution Approach 2:
The frame structure is segmented into different subframe types (special subframes and downlink subframes), each with specific roles. This segmentation allows the system to optimize different parts of the frame for different purposes, making the overall structure more manageable and less complex while supporting repeated transmissions effectively.
Data Source
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AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. In addition, the apparatus may determine a first set of subframes in the narrowband TDD frame structure used for transmitting a downlink control channel to a UE. In one aspect, a last subframe in the first set of subframes may be subframe n. Further, the apparatus may determine a second set of subframes in the narrowband TDD frame structure used for transmitting a downlink data channel to the UE. In certain aspects, a first subframe in the second set of subframes may be delayed based on k 0 number of subframes after the subframe n. In certain other aspects, a last subframe in the second set of subframes may be subframe n + k 0 + x. Additionally, the apparatus may signal first information associated with the k 0 number of subframes to the UE in a first delay field in a DCI transmission.