CSI Coding Strategy for Multi-Cell Carrier Aggregation
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Solution Overview
Problem
In wireless communication systems, particularly in LTE standards, the increased number of component carriers for carrier aggregation leads to a rapid increase in bits required for channel state information (CSI) and HARQ-ACK, making error transmission and detection challenging, which can have significant ripple effects on system performance.
Innovation Solution
A method for determining whether to perform separate or joint coding on channel state information (CSI) based on rules configured per individual CSI, PUCCH reporting type, or PUCCH reporting mode, considering factors like bit width and rank value of the downlink channel, to efficiently manage CSI transmission in multi-cell scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If carrier aggregation with increased number of component carriers is implemented, then bandwidth and data transmission capacity are improved, but the number of bits for channel state information and HARQ-ACK increases rapidly leading to higher error probability
Solution Approach 1:
The patent segments channel state information into multiple groups (first group and second group) with different prioritization levels. High-priority CSI is placed in the first group while low-priority CSI is placed in the second group, allowing selective transmission based on available resources and reducing error probability for critical information.
Solution Approach 2:
Different coding schemes and prioritization rules are applied to different groups of CSI based on their specific characteristics and importance. The patent applies separate coding methods (e.g., Reed-Muller code, polar code) to different CSI groups, optimizing reliability for each type of information locally rather than using a uniform approach.
2Reliability
If separate coding is performed for each CSI, then reliability of individual CSI transmission is improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent segments CSI into priority-based groups and applies separate coding only within each group rather than for every individual CSI report. This reduces the number of separate coding operations needed while maintaining reliability for high-priority information.
Solution Approach 2:
Multiple low-priority CSI reports are merged into a single second group that can be transmitted together using a unified coding scheme. This combining approach reduces overall coding complexity while still preserving the reliability of individual high-priority CSI through separate coding in the first group.
3Device complexity
If joint coding is performed for multiple CSI, then device complexity is reduced, but the impact of errors increases due to ripple effects across multiple CSI
Solution Approach 1:
The patent divides CSI into separate priority groups that are coded independently. This segmentation ensures that an error in one group does not propagate to other groups, eliminating the ripple effect while still allowing joint coding within each group to maintain low complexity.
Solution Approach 2:
Different coding strategies are applied locally to different CSI groups based on their priority and error sensitivity. High-priority CSI in the first group receives more robust separate coding to minimize error impact, while low-priority CSI in the second group uses simpler joint coding where error impact is less critical.
Data Source
AI summary
A method for a channel coding of channel state information (CSI) in a wireless communication system according to an embodiment of the present invention may comprise the steps of: determining whether to perform an individual coding or a joint coding on a multi-CSI for a CSI process or a plurality of cells to be transmitted in one subframe; and performing a channel coding on an input bit for the multi-CSI according to the determined coding scheme, wherein whether to perform the individual coding or the joint coding may be determined according to a rule set for each individual CSI, for each physical uplink control channel (PUCCH) reporting type, or for each PUCCH reporting mode.