ePDCCH Resource Mapping for Precoding and Scheduling Gains
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Solution Overview
Problem
The LTE system's control channel capacity is limited due to the introduction of technologies like MIMO and CoMP, leading to inefficiencies in transmitting control information, particularly with the ePDCCH, which faces challenges in resource configuration and multiplexing flexibility.
Innovation Solution
A method that determines physical resource blocks with sub-blocks, groups them into sub-block groups, performs interleaving on logical candidate elements, and maps them to sub-block flocks to enhance the flexibility of control channel resource configuration, allowing for better transmission of control information by placing candidate control channels on consecutive time-frequency resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If control channels are allocated to consecutive time-frequency resources in centralized transmission manner, then beamforming/precoding gain is obtained, but flexibility of resource configuration is reduced
Solution Approach 1:
The patent divides the control channel resources into multiple search spaces (common search space and UE-specific search space), and further segments them into candidate positions. This segmentation allows the system to maintain consecutive resource allocation for beamforming while enabling flexible configuration through different search space designs and candidate position selections.
Solution Approach 2:
The patent introduces dynamic search space configuration where the base station can flexibly configure the number of candidate positions, aggregation levels, and resource block assignments. This dynamic configuration enables the system to adapt resource allocation to different channel conditions and traffic requirements while maintaining the consecutive resource structure needed for beamforming.
2Quantity of substance
If control channel capacity is increased to support MIMO and CoMP technologies, then control information transmission capability is improved, but system complexity increases
Solution Approach 1:
The patent designs a universal ePDCCH structure that can support multiple functions including MIMO and CoMP technologies. By using UE-specific reference signals for demodulation and flexible search space configuration, the same control channel structure can serve multiple purposes, increasing control channel capacity without proportionally increasing system complexity.
Solution Approach 2:
The patent increases control channel capacity by changing key parameters such as the number of candidate positions per search space, aggregation levels (1, 2, 4, 8), and the number of resource blocks allocated. These parameter adjustments allow the system to scale control channel capacity to support MIMO and CoMP while managing complexity through standardized parameter sets.
3Reliability
If blind detection is performed on terminal side for ePDCCH, then control channel transmission reliability is improved, but detection complexity and time consumption increase
Solution Approach 1:
The patent segments the blind detection process into structured search spaces with defined candidate positions and aggregation levels. This segmentation allows the terminal to systematically search through candidate positions rather than performing exhaustive blind detection, reducing detection complexity while maintaining reliability through the structured approach.
Solution Approach 2:
The base station performs preliminary configuration of search spaces and candidate positions before transmission. This preliminary action provides the terminal with advance information about where to search for control channels, significantly reducing the complexity and time of blind detection while maintaining transmission reliability through the pre-configured search structure.
Data Source
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Figure 3A~3C
AI summary
The present invention provides a method, base station, and user equipment for transmitting a control channel. Grouping is performed, according to an aggregation level of the to-be-transmitted control channel, on sub-blocks in physical resource blocks configured by the base station for the to-be-transmitted control channel, then interleaving is performed, and then candidate control channels are mapped to the interleaved sub-blocks, so that any candidate control channel of the to-be-transmitted control channel is sent on consecutive time-frequency resources as possible, and meanwhile different candidate control channels are on different PRB pairs as possible. In this way, the base station may have better flexibility during actual sending of the ePDCCH, thereby not only achieving a precoding gain and facilitating better transmission of control information, but also achieving a larger scheduling gain.