Uplink Signal Transmission Timing Advance Management
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Solution Overview
Problem
In 3GPP LTE systems, the simultaneous transmission of uplink signals is limited by power constraints, leading to potential transmission errors due to the use of a single timing advance value across multiple serving cells, which can result in incorrect decoding of uplink channels.
Innovation Solution
Configuring multiple timing advance (TA) groups allows for independent timing alignment for each serving cell, enabling simultaneous transmission of uplink channels like SRS and PUSCH, with the option to drop SRS transmission when total power exceeds the maximum, ensuring PUSCH is not transmitted in the SRS symbol to prevent decoding errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single timing advance value is used across multiple serving cells, then device complexity is reduced, but transmission reliability deteriorates due to potential decoding errors
Solution Approach 1:
The patent segments the timing advance management by introducing multiple TA groups (first TA group and second TA group) instead of using a single timing advance value for all serving cells. Each TA group can be independently configured and managed, allowing different timing advance values to be applied to different groups of serving cells. This segmentation resolves the contradiction by maintaining simplicity within each group while improving overall transmission reliability through group-specific timing alignment.
2Productivity
If multiple uplink signals are transmitted simultaneously, then communication productivity is improved, but power constraints are violated leading to transmission errors
Solution Approach 1:
The patent implements dynamic signal transmission strategies where the transmission of uplink signals (such as SRS and PUSCH) is adaptively controlled based on power availability and signal priority. When power constraints are detected, the system dynamically adjusts which signals are transmitted and in what order, rather than attempting simultaneous transmission of all signals. This dynamic approach maintains high productivity by transmitting multiple signals when possible while ensuring reliability by preventing power constraint violations.
3Use of energy by moving object
If SRS and PUSCH are transmitted simultaneously in the same subframe, then use of energy is optimized, but decoding errors occur due to power limitation
Solution Approach 1:
The patent employs preliminary action by configuring transmission rules and power allocation strategies in advance for SRS and PUSCH signals. Before actual simultaneous transmission occurs, the system pre-determines which signals can be transmitted together based on power constraints and signal priorities. This preliminary configuration prevents decoding errors by ensuring that simultaneous transmissions are only attempted when power limitations will not be violated, thus maintaining both energy efficiency and reliability.
Data Source
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AI summary
A method and device for transmitting an uplink signal in a wireless communication system is provided. A user equipment transmits a physical uplink shared channel (PUSCH) on a SRS subframe for a first serving cell to a base station if a SRS transmission on the SRS subframe for the first serving cell is overlapped with an uplink transmission for a second serving cell. The PUSCH is transmitted on remaining orthogonal frequency division multiplexing (OFDM) symbols in the SRS subframe except a single OFDM symbol reserved for the SRS transmission regardless of whether a SRS is transmitted on the single OFDM symbol or not.