Uplink Subframe Indication for Flexible LTE TDD on Unlicensed Spectrum
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Solution Overview
Problem
The existing TDD manner in LTE systems using unlicensed spectrums is inflexible in uplink and downlink configurations, leading to low transmission efficiency due to fixed uplink and downlink time slots, which can result in channel resource snatching by WiFi devices and frequent interruptions in downlink data transmission.
Innovation Solution
A method and device that dynamically allocate or adjust uplink subframes within each indication period, allowing the base station to set a flexible frame structure for TDD frames, even in scenarios where conventional frame structures are inapplicable, by transmitting indication signaling in downlink subframes to notify terminals of uplink subframe positions, thereby enhancing transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fixed uplink and downlink configurations are used in TDD mode on unlicensed spectrum, then the system structure is simple and easy to implement, but the transmission efficiency is low and channel resources are frequently snatched by WiFi devices
Solution Approach 1:
The patent applies dynamics by enabling the base station to dynamically indicate uplink subframe positions through downlink control information (DCI) signaling. Instead of fixed TDD configurations, the system allows flexible adjustment of uplink subframe locations within indication periods, making the frame structure adaptable to varying transmission needs and reducing WiFi interference through dynamic resource allocation
Solution Approach 2:
The patent changes the parameter of frame structure flexibility by introducing dynamic indication periods and configurable indication positions. The base station can modify uplink subframe allocation parameters within each indication period, transforming the rigid fixed configuration into a flexible parameter-driven structure that optimizes transmission efficiency while managing complexity through standardized signaling mechanisms
2Adaptability or versatility
If dynamic allocation of uplink subframes is implemented, then the transmission efficiency is improved and adaptability to different scenarios increases, but the system complexity and signaling overhead increase
Solution Approach 1:
The patent implements periodic action by introducing indication periods with configurable durations (e.g., 20ms, 40ms, 80ms). Within each periodic indication period, the base station sends DCI signaling to indicate uplink subframe positions. This periodic structure provides regular opportunities for dynamic adjustment while maintaining predictable system behavior, balancing adaptability with manageable complexity through rhythmic resource allocation cycles
Solution Approach 2:
The patent applies preliminary action by having the base station pre-configure indication period parameters and indication positions before actual uplink transmission. The DCI signaling is sent in advance within each indication period to notify terminals of upcoming uplink subframe positions, allowing terminals to prepare accordingly. This advance indication reduces real-time decision complexity while maintaining high adaptability to varying transmission scenarios
Data Source
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AI summary
Provided is a method for indicating an uplink subframe on an unlicensed spectrum, including: determining a current indication period and a next indication period according to a preset period duration; acquiring an indication position preset in the current indication period, where the indication position is a timing position of one or more preset downlink subframes; and when the indication position in the current indication period arrives, transmitting indication signaling in a downlink subframe corresponding to the indication position.