Radio Terminal Transmission Timing Assignment Based on Speed
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Solution Overview
Problem
Massive MIMO systems face limitations due to channel reciprocity requirements and pilot contamination, which affect transmission timing accuracy and resource allocation efficiency, especially in scenarios with varying terminal speeds and high antenna-to-terminal ratios.
Innovation Solution
A method to determine the speed of a radio terminal and assign transmission timing within uplink or downlink transmission intervals, optimizing SRS periodicity and resource allocation to reduce interference and overhead, while ensuring accurate channel state information acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If orthogonal pilot sequences are assigned to every terminal, then channel state information acquisition accuracy is improved, but the maximum number of orthogonal pilot sequences is upper-bounded by the coherence interval, leading to resource allocation inefficiency when the number of terminals increases
Solution Approach 1:
The patent assigns different SRS periodicities to different terminals based on their channel coherence characteristics. Terminals with high channel coherence (e.g., low mobility) use longer SRS periodicities, while terminals with low channel coherence (e.g., high mobility) use shorter SRS periodicities. This local differentiation resolves the contradiction by optimizing resource allocation for each terminal's specific channel conditions rather than using a uniform approach for all terminals.
2Reliability
If SRS periodicity is reduced to improve channel state information accuracy for high-speed terminals, then transmission quality is improved, but reference signal overhead increases
Solution Approach 1:
The patent implements terminal-specific SRS periodicity configuration where each terminal's SRS periodicity is adapted to its channel coherence characteristics. High-speed terminals with low channel coherence receive shorter SRS periodicities to maintain transmission quality, while low-speed terminals with high channel coherence receive longer SRS periodicities to minimize overhead. This resolves the contradiction by applying different quality levels locally rather than uniformly across all terminals.
Solution Approach 2:
The patent dynamically adjusts SRS periodicity based on terminal mobility and channel conditions. The network can reconfigure SRS periodicity parameters according to changing terminal speeds and channel coherence, allowing the system to adapt to varying transmission quality requirements while optimizing resource usage. This dynamic adjustment resolves the contradiction by making the system flexible rather than static.
3Device complexity
If a single SRS periodicity is configured for all terminals, then device complexity is reduced, but terminals with different speeds experience suboptimal channel state information accuracy
Solution Approach 1:
The patent introduces terminal-specific SRS periodicity configuration where each terminal is assigned a periodicity tailored to its channel coherence characteristics. This local differentiation improves channel state information accuracy for terminals with varying speeds while maintaining manageable complexity through automated network-side configuration and terminal reporting mechanisms.
Solution Approach 2:
The patent enables dynamic SRS periodicity adjustment based on terminal mobility feedback. Terminals report their mobility status or channel coherence measurements, and the network dynamically configures appropriate SRS periodicities. This dynamic approach balances complexity and performance by adapting to actual terminal conditions rather than using fixed uniform configuration.
Data Source
AI summary
The present invention relates to a method of assigning a transmission timing to a radio terminal in a radio network system including at least a radio network node and a radio terminal and employing a time division duplex method dividing a transmission time in an uplink transmission time interval and a downlink transmission time interval for transmission between the radio network node and the radio terminal, comprising the following steps: determining a speed of movement of the radio terminal with respect to the radio network node; assigning to the radio terminal, based on the speed of movement, a transmission timing in the downlink or uplink transmission time interval. The present invention relates further to a radio network node and a radio terminal adapted to assigning a transmission timing according to the above method.