Aperiodic SRS Bandwidth Control for LTE-A Uplink Channel Sounding
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Solution Overview
Problem
In the Long Term Evolution Advanced (LTE-A) standard, there is a need for improved methods and apparatuses to configure the bandwidth and transmit power levels of aperiodically transmitted sounding reference signals (SRS) from a mobile station to a base station, particularly in response to trigger messages.
Innovation Solution
A mobile station and base station apparatus are designed to manage aperiodic SRS transmission by adjusting the number of antenna ports, bandwidth, and subframe timing based on UL and DL grants, using RRC signaling and DCI formats to ensure consistent and efficient SRS transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If aperiodic SRS transmission is implemented in LTE-A, then channel characterization is improved, but configuration complexity increases
Solution Approach 1:
The patent segments the SRS configuration into multiple parameter sets (first parameter set and second parameter set) that can be independently configured and selected. This allows the system to divide the complex configuration into manageable parts, where different parameter sets can be applied to different antenna ports or transmission scenarios, thereby improving channel characterization while managing configuration complexity through structured organization.
Solution Approach 2:
The patent implements dynamic selection between different parameter sets based on transmission conditions. The mobile station and base station can dynamically switch between the first and second parameter sets for aperiodic SRS transmission, allowing the system to adapt to varying channel conditions and transmission requirements. This dynamic approach enables improved channel characterization through flexible configuration selection without permanently increasing system complexity.
2Adaptability or versatility
If multiple parameter sets are configured for aperiodic SRS, then transmission flexibility is improved, but signaling overhead increases
Solution Approach 1:
The patent performs preliminary configuration by pre-defining multiple parameter sets through RRC signaling before actual SRS transmission occurs. These parameter sets including bandwidth, frequency domain position, and other SRS parameters are prepared in advance and stored at both the mobile station and base station. When aperiodic SRS transmission is triggered, the pre-configured parameter sets can be directly selected and applied, providing transmission flexibility while avoiding the need to signal all parameters each time, thus reducing signaling overhead.
3Measurement precision
If SRS bandwidth is increased, then channel measurement accuracy is improved, but power consumption increases
Solution Approach 1:
The patent applies local quality by configuring different bandwidth parameters for different parameter sets and allowing selective application to specific antenna ports or transmission scenarios. Instead of uniformly increasing bandwidth across all SRS transmissions, the system can apply wider bandwidth only when and where higher measurement accuracy is needed, while using narrower bandwidth in other cases. This localized approach to bandwidth configuration improves channel measurement accuracy where required while minimizing overall power consumption.
Data Source
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AI summary
A mobile station for use in a wireless network that operates according to the Long-Term Evolution Advanced (LTE-A) standard. The mobile station is operable to transmit an aperiodic sounding reference signal (SRS) to a base station in response to a triggering grant received from the base station. The bandwidth on which the mobile station transmits the aperiodic SRS depends on a type of the triggering grant. The type of the triggering grant is one of a downlink grant, an uplink multiple-input, multiple-output (MIMO) grant, and an uplink single-input, multiple-output (SIMO) grant.