Deterministic CSI/SRS Reporting During DRX Active Time
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Solution Overview
Problem
Existing LTE systems face challenges in efficiently managing channel quality reporting and sounding reference symbols, particularly in scenarios involving carrier aggregation, which can lead to suboptimal resource allocation and increased power consumption due to inefficient DRX cycles.
Innovation Solution
Implementing deterministic UE behavior for CSI/SRS reporting, including aperiodic CSI triggers and type-1 SRS transmissions, to optimize resource allocation and reduce power consumption by aligning reporting with active DRX cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic CSI/SRS reporting is performed during DRX cycles, then channel quality feedback is provided, but power consumption increases and resource allocation becomes inefficient
Solution Approach 1:
The patent applies periodic action by configuring CSI/SRS reporting to occur only during specific DRX active times rather than continuously. The network configures reporting periodicity and timing offsets that align with DRX cycles, enabling the UE to enter low-power states during DRX non-active periods while maintaining reliable channel quality feedback during active periods when the UE is already awake for data reception.
2Use of energy by moving object
If CSI/SRS reporting is aligned with DRX active times, then power consumption is reduced, but reporting timing becomes less flexible
Solution Approach 1:
The patent applies dynamics by introducing configurable timing offsets and multiple reporting mode options that allow the system to adapt reporting timing based on traffic conditions. The network can dynamically adjust the timing offset between DRX active time and CSI/SRS reporting, and switch between different reporting modes (e.g., reporting only during on-duration vs. reporting during entire active time) to balance power savings with timing flexibility requirements.
3Productivity
If deterministic UE behavior is implemented for CSI/SRS reporting, then resource allocation efficiency improves, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by having the network pre-configure all necessary parameters for CSI/SRS reporting during DRX cycles before the UE needs to execute them. The RRC configuration includes reporting periodicity, timing offsets, and conditions for reporting, allowing the UE to deterministically determine whether to report based on simple comparisons with pre-configured parameters rather than complex real-time decisions, thus improving resource allocation efficiency while maintaining low UE complexity.
Data Source
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AI summary
The invention relates to a method for transmitting a periodic channel quality report (CSI) and/or a sounding reference symbol (SRS) from a UE to an eNodeB. To avoid double decoding at the eNodeB in transient phases, a deterministic behavior of the UE is defined by the invention, according to which the eNodeB can unambiguously determine whether the UE will transmit the CSI/SRS or not. According to one embodiment, the UL grants and/or DL assignments received until and including subframe N-4 only are considered; UL grants and/or DL assignments received by the UE after subframe N-4 are discarded for the determination. Additionally, DRX-related timers at subframe N-4 are considered for the determination. In a second embodiment, DRX MAC control elements from the eNodeB, instructing the UE to enter DRX, i.e. become Non-Active, are only considered for the determination if they are received before subframe N-4, i.e. until and including subframe N-(4+k).