E-PDCCH Transmission via Distributed E-CCE Selection
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Solution Overview
Problem
There is a lack of specific solutions for transmitting downlink control information over Enhanced Physical Downlink Control Channels (E-PDCCHs) in both localized and distributed transmission modes within the LTE Rel-11 system.
Innovation Solution
The method involves a base station selecting and transmitting downlink control information to User Equipment (UE) using localized or distributed Enhanced Control Channel Elements (E-CCEs) within specific time-frequency resource regions, with the UE performing blind detection on these channels at supported aggregation levels. In localized mode, E-CCEs are consecutive in frequency domain, while in distributed mode, E-CCEs span across multiple resource clusters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If legacy PDCCH transmission method is used in LTE Rel-8/9/10, then control information can be transmitted in the control region, but the system lacks flexibility in resource allocation and cannot support enhanced transmission modes
Solution Approach 1:
The control channel is segmented into multiple E-CCEs (Enhanced Control Channel Elements), which can be further divided into E-REGs (Enhanced Resource Element Groups). This segmentation enables flexible resource allocation by allowing different aggregation levels (1, 2, 4, or 8 E-CCEs) to be configured based on channel conditions and traffic requirements, thus improving adaptability while maintaining manageable structural complexity.
Solution Approach 2:
The patent introduces a new dimension for control channel transmission by defining E-PDCCH in the data region rather than the traditional control region. This dimensional shift allows simultaneous support for both legacy PDCCH and enhanced E-PDCCH transmissions, providing backward compatibility while enabling new transmission modes without increasing overall system complexity.
2Reliability
If PDCCH blind detection is performed across all aggregation levels in the control region, then downlink control information can be reliably detected, but the detection complexity and processing time increase significantly
Solution Approach 1:
The patent applies local quality by configuring UE-specific search spaces with predetermined aggregation levels based on individual UE channel conditions and service requirements. Instead of requiring all UEs to perform blind detection across all aggregation levels, each UE monitors only its configured aggregation levels, significantly reducing detection complexity while maintaining reliability through localized optimization.
Solution Approach 2:
The network performs preliminary configuration of UE-specific search spaces and aggregation levels before actual data transmission. This preliminary action allows UEs to prepare their detection parameters in advance, reducing real-time processing complexity during blind detection while ensuring reliable control information reception.
3Productivity
If control channels are transmitted in the control region only, then legacy compatibility is maintained, but resource utilization efficiency and support for enhanced features are limited
Solution Approach 1:
The patent creates a universal control channel framework where E-PDCCH can function in both the control region (for backward compatibility) and the data region (for enhanced features). This multi-functional approach allows the same E-CCE/E-REG structure to serve both legacy and enhanced transmission modes, improving resource utilization efficiency while maintaining adaptability across different transmission scenarios.
Data Source
AI summary
Disclosed are a method and a device for sending and detecting an enhanced physical downlink control channel (E-PDCCH), relating to the field of wireless communications, and used for solving the problem of how to send downlink control information through the E-PDCCH. In the method, when a current subframe needs to send downlink control information to a terminal by adopting a frequency domain distributed transmission mode, a base station selects, according to the current aggregation level, at least one available distributed E-CCE in a distributed E-PDCCH time frequency resource area of the current subframe, and uses the selected distributed E-CCE to send the downlink control information to the terminal. The present application solves the problem of how to transmit downlink control information through the E-PDCCH.