CSI-RS Resource Allocation via DCI Cyclic Shift Reuse
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE communication networks, there is a need to efficiently handle aperiodic CSI feedback for multiple serving cells, which currently results in increased overhead and computational complexity for user equipment (UE), leading to potential channel mismatch and performance degradation due to large feedback delays and reduced CSI-RS coverage range.
Innovation Solution
A method where the UE receives grants identifying CSI-RS resources for multiple serving cells, allowing it to calculate and transmit CSI reports dynamically, using existing cyclic shift fields in DCI formats to indicate CSI-RS resources, thereby reducing overhead and enhancing CSI-RS resource allocation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the UE receives grants identifying CSI-RS resources for multiple serving cells, then the CSI report accuracy is improved, but the UE computational complexity increases
Solution Approach 1:
The patent segments the CSI reporting process by handling each serving cell's CSI-RS resources independently through separate identifiers in the grant. This allows the UE to process and report CSI for multiple cells without requiring a single complex unified processing mechanism, thereby reducing computational complexity while maintaining accuracy.
Solution Approach 2:
The patent applies preliminary action by pre-configuring the UE with multiple CSI-RS resource identifiers before the actual CSI reporting. The UE stores these identifiers in advance, so when a grant arrives, it can quickly retrieve and process the corresponding CSI-RS resources without performing complex real-time identification, thus reducing computational burden during CSI calculation.
2Loss of information
If the UE calculates and transmits CSI reports for multiple serving cells, then the channel state information completeness is improved, but the feedback delay increases
Solution Approach 1:
The patent uses preliminary action by having the UE pre-configure and store multiple CSI-RS resource identifiers before the feedback is needed. When the grant arrives, the UE can immediately retrieve the corresponding pre-stored identifiers and calculate CSI reports without waiting for resource identification during the feedback process, thereby reducing feedback delay while maintaining information completeness.
Solution Approach 2:
The patent applies dynamics by allowing flexible timing in CSI report transmission. The UE can transmit CSI reports for multiple serving cells at different rates or priorities based on channel conditions and network requirements, rather than requiring all CSI reports to be transmitted simultaneously, thus reducing overall feedback delay while maintaining completeness.
3Quantity of substance
If the UE uses existing cyclic shift fields in DCI formats to indicate CSI-RS resources, then the downlink overhead is reduced, but the CSI-RS resource allocation flexibility decreases
Solution Approach 1:
The patent applies universality by making the cyclic shift fields in DCI formats serve dual purposes: both indicating DMRS characteristics for uplink data scheduling and identifying CSI-RS resources for CSI reporting. This multi-functionality eliminates the need for separate dedicated fields for CSI-RS indication, thereby reducing downlink overhead while maintaining allocation flexibility through the existing field's versatile usage.
Solution Approach 2:
The patent uses parameter changes by interpreting the cyclic shift field values differently based on the grant context. When used for CSI-RS resource indication, the same field is interpreted as a resource identifier rather than a DMRS parameter, allowing the system to reduce overhead by reusing existing fields with changed semantic meaning based on operational context.
Data Source
AI summary
Embodiments herein show a method performed by a user equipment for handling communication via a set of serving cells comprising a first serving cell and a second serving cell of a communication network. The user equipment receives a grant on a first serving cell, wherein the grant comprises a first identifier identifying Channel State Information Reference Signal (CSI-RS) resources of the first serving cell. Furthermore, the user equipment calculates a first CSI report for the first serving cell using the CSI-RS resources identified by the first identifier; and calculates a second CSI report for a second serving cell, using CSI-RS resources of the second serving cell identified by a second identifier, the second identifier being received previously in a grant on the second serving cell. The user equipment then transmits the first and second CSI reports to a network node serving the first serving cell.