Search Space Determination for Reducing Channel Estimation Complexity
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Solution Overview
Problem
In LTE systems, the existing methods for determining search spaces in user equipment (UE) lead to increased channel estimation complexity and high blocking probabilities due to overlapping control channel candidates, resulting in inefficient resource utilization and increased latency.
Innovation Solution
The method involves determining a search space where the control channel elements (CCEs) of a low aggregation level are a subset of those in the maximum aggregation level, with control channel candidates being discretely and unevenly distributed, allowing for multiplexing of channel estimation and reduced demodulation complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If search spaces for different aggregation levels are determined using existing LTE methods, then control channel candidates can be detected, but channel estimation complexity increases and blocking probability increases due to overlapping CCEs
Solution Approach 1:
The patent applies nesting by making the search space for a lower aggregation level a subset of the search space for a higher aggregation level. Specifically, the CCEs for aggregation level L are made a subset of CCEs for aggregation level 2L, allowing channel estimation results to be reused across multiple aggregation levels and reducing overall estimation complexity while minimizing blocking probability.
Solution Approach 2:
The patent makes channel estimation results universal across different aggregation levels by ensuring that CCEs for lower aggregation levels are subsets of higher aggregation levels. This allows a single channel estimation to serve multiple detection purposes, reducing the total number of estimations required and improving resource utilization efficiency.
2Productivity
If control channel candidates are distributed evenly in search spaces, then detection coverage is maximized, but resource utilization efficiency decreases and latency increases
Solution Approach 1:
The patent introduces asymmetric distribution of control channel candidates within the nested search space structure. Instead of uniform distribution, candidates are positioned to optimize both detection performance and resource efficiency, with the distribution pattern adapting to the nested relationship between different aggregation levels.
Solution Approach 2:
The patent applies local quality by allowing different distribution characteristics in different regions of the search space. The discrete and uneven distribution enables better local resource utilization while maintaining overall detection coverage, with specific candidate positions optimized for their local context within the nested structure.
Data Source
AI summary
In a method and apparatus for determining a search space, a control resource set of a terminal device is corresponding to at least two aggregation levels. The at least two aggregation levels include a maximum aggregation level and a first aggregation level, the first aggregation level is less than the maximum aggregation level, and the maximum aggregation level is the highest aggregation level of the at least two aggregation levels. Based on the method and the apparatus, a first search space corresponding to the first aggregation level is determined based on a quantity of control channel elements (CCEs) included in the control resource set of the terminal device and the maximum aggregation level.