Uplink Downlink Transmission Alignment in 5G Dynamic TDD
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Solution Overview
Problem
In the context of 5G communication, existing technologies face challenges in aligning uplink and downlink transmission in flexible duplex/dynamic TDD modes, leading to cross-link interference due to differences in timing relationships, numerology, and cyclic prefix durations, which affects signal stability and interference management.
Innovation Solution
The method involves configuring timing advance adjustments and aligning cyclic prefixes and gaps within time units to synchronize uplink and downlink transmissions, using orthogonal frequency division multiplexing symbols, slots, or frames, to minimize interference between reference signals and control channels across devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If flexible duplex/dynamic TDD mode is used to dynamically allocate uplink and downlink transmission resources, then adaptability and resource allocation flexibility are improved, but cross-link interference between adjacent devices increases
Solution Approach 1:
The patent applies preliminary action by determining the transmission direction (uplink or downlink) for each device before actual transmission occurs. The network device determines timing advance values and transmission directions in advance, allowing devices to pre-synchronize their transmissions. This prevents cross-link interference by ensuring that uplink and downlink transmissions are properly timed and directed before they occur, rather than reacting to interference after it happens.
Solution Approach 2:
The patent implements dynamics by allowing the transmission direction and timing advance values to be dynamically adjusted for each device based on real-time network conditions. The network device can independently determine and update timing advance values for different devices, enabling flexible adaptation to changing channel conditions while maintaining synchronization. This dynamic approach allows the system to optimize resource allocation while preventing cross-link interference through continuous timing adjustments.
2Adaptability or versatility
If different timing relationships are used for PDCCH to downlink data and PDCCH to uplink data, then adaptability to different transmission scenarios is improved, but transmission alignment and synchronization become more difficult
Solution Approach 1:
The patent applies local quality by allowing different timing relationships to be applied locally to different devices based on their specific transmission scenarios. Each device can have its own timing advance value and transmission direction determined independently by the network device. This enables the system to optimize timing for each local scenario (downlink or uplink) while maintaining overall network synchronization, resolving the contradiction between adaptability and alignment precision.
3Ease of operation
If reference signals are transmitted without alignment, then transmission simplicity is improved, but channel estimation accuracy and data demodulation performance deteriorate
Solution Approach 1:
The patent applies preliminary action by determining the transmission direction for reference signals before they are transmitted. The network device determines whether each device should transmit uplink or downlink reference signals in advance, and configures appropriate timing advance values. This ensures that reference signals from different devices are properly aligned in time, maintaining channel estimation accuracy while keeping the transmission process simple through automated direction determination.
Data Source
AI summary
Provided is a method and apparatus for aligning uplink transmission with downlink transmission. The method includes at least one of: obtaining a time unit; performing at least one of uplink transmission or downlink transmission on a spectrum resource corresponding to the time unit; or configuring at least one timing advance (TA) adjustment amount over the time unit.