Discrete User-Specific Search Space for LTE Control Channel Diversity
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Solution Overview
Problem
The existing methods for sending downlink control information in LTE networks are limited, particularly in LTE-Advanced systems, where the number of PDCCH symbols may not meet the increased user requirements, leading to interference issues between different eNodeBs and inadequate transmission performance for UEs at the cell edge.
Innovation Solution
A method and device for sending downlink control information by determining discrete user-specific search spaces, where control channel resources are distributed discretely, allowing for improved resource allocation and diversity gain, enabling more efficient transmission of physical downlink control information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous control channel resources are allocated in the existing LTE system, then the resource allocation is simple and continuous, but the diversity gain is insufficient and cell edge UE performance is poor
Solution Approach 1:
The patent divides the control channel resources into discrete segments distributed across different frequency locations. Instead of allocating continuous resources, the search space is segmented into multiple discrete resource locations, allowing the UE to detect PDCCH candidates at these distributed positions. This segmentation provides frequency diversity while maintaining manageable detection complexity through defined search space patterns.
Solution Approach 2:
The patent transitions from one-dimensional continuous resource allocation to two-dimensional discrete resource distribution across frequency. By dispersing control channel resources across multiple frequency locations rather than allocating them contiguously, the system exploits the frequency dimension to achieve diversity gain and improve robustness against frequency-selective fading.
2Productivity
If the number of PDCCH symbols is increased to meet more user requirements, then the downlink control capacity is improved, but the interference between different eNodeBs increases
Solution Approach 1:
The patent applies local quality by allowing different eNodeBs to use different discrete frequency locations for their control channel resources. Each eNodeB can configure its search space at specific frequency positions, creating localized resource allocation that increases overall system capacity while managing interference through spatial and frequency separation between cells.
3Reliability
If discrete user-specific search space is used, then the diversity gain and scheduling gain are enhanced, but the UE detection complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the UE with discrete search space locations and aggregation level information before actual PDCCH transmission. The network signals the UE about the specific frequency locations and resource configurations in advance, allowing the UE to prepare its detection strategy and reduce real-time detection complexity while still benefiting from the diversity provided by discrete resource distribution.
Data Source
AI summary
Disclosed are a method and a device for sending and receiving downlink control information. The method comprises: discrete user-specific search space is determined, control channel resources corresponding to the discrete user-specific search spaces being distributed discretely; and the downlink control information on the discrete user-specific search space is sent. Through the disclosure, the diversity effect of sending physical downlink control information is improved.