Dynamic SRS Transmission Timing in LTE Base Stations
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Solution Overview
Problem
In the LTE system, radio resources used for SRS transmission are fixedly allocated regardless of the presence or absence of a data channel signal (PUSCH), leading to inefficient use of resources.
Innovation Solution
A method where the base station apparatus transmits an uplink scheduling grant with instructions for SRS transmission, allowing the mobile station apparatus to dynamically control the subframe for SRS multiplexing, ensuring SRS is transmitted only when necessary, thereby optimizing radio resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SRS is transmitted periodically in LTE system regardless of data channel presence, then channel quality measurement can be performed regularly, but radio resources are wasted when no data transmission is needed
Solution Approach 1:
The patent applies dynamics by making the SRS transmission periodicity configurable and adaptable. The base station can dynamically adjust the SRS transmission cycle based on channel conditions and data transmission requirements, allowing the system to transition between frequent periodic measurements and resource-saving sparse measurements. This resolves the contradiction by making the measurement frequency dynamic rather than fixed, balancing reliability needs with resource efficiency.
Solution Approach 2:
The patent changes the parameter of SRS transmission periodicity from a fixed value to a configurable parameter. By allowing the periodicity to be adjusted based on system conditions (such as whether data channel transmission is occurring), the system can optimize between measurement reliability and resource consumption. When data transmission occurs, shorter periodicity ensures accurate channel quality measurement; when no data transmission occurs, longer periodicity reduces resource waste.
2Measurement precision
If SRS transmission periodicity is fixed at 5 msec intervals, then channel quality can be measured frequently, but radio resource efficiency decreases when data channel signals are not transmitted
Solution Approach 1:
The patent makes the SRS transmission periodicity dynamic rather than fixed at 5 msec. The base station can adjust the periodicity according to actual data transmission needs and channel conditions, allowing the system to achieve high measurement frequency when necessary and low frequency when unnecessary, thereby improving overall radio resource utilization efficiency while maintaining measurement precision when needed.
Solution Approach 2:
The patent modifies the periodic action of SRS transmission by making the period variable. Instead of fixed 5 msec intervals, the system implements configurable periodic intervals that can be adjusted based on whether data channel transmission is occurring. This allows the periodic measurement action to be optimized - frequent when data transmission requires accurate channel knowledge, sparse when resources should be conserved.
Data Source
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AI summary
To efficiently use radio resources used in transmission of SRS, a base station apparatus (eNode B) transmits a scheduling grant including an instruction for transmission of a Sounding Reference Signal (SRS), and a mobile station apparatus (UE) transmits the SRS in response to the scheduling grant. The SRS is transmitted in the same subframe, another subframe or a previous subframe by the predetermined number of subframes as, immediately before, or before a subframe of a PUSCH (Physical Uplink Shared Channel) that the scheduling grant instructs to transmit.