E-PDCCH Mapping Optimizes Multiplexing Efficiency
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Solution Overview
Problem
The multiplexing efficiency of Enhanced Physical Downlink Control Channels (E-PDCCHs) in LTE systems is low due to limitations in mapping and transmission modes, particularly when transmitting to multiple UEs with different E-PDCCH modes, leading to inefficient use of physical resources.
Innovation Solution
The method involves mapping control channel candidates to physical resources such that eREGs are allocated to the fewest localized eCCEs in a PRB pair, optimizing the distribution of eREGs across PRB pairs to improve multiplexing efficiency across different E-PDCCH modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If eREGs are mapped to physical resources in a distributed E-PDCCH transmission mode, then frequency diversity gain is obtained, but the multiplexing efficiency with localized E-PDCCH is reduced
Solution Approach 1:
The patent segments the physical resource block pair into multiple localized eCCEs, and further segments eCCEs into eREGs. By controlling the mapping of eREGs to eCCEs and PRBs, the system can separately optimize localized and distributed E-PDCCH transmissions within the same resource structure, resolving the conflict between frequency diversity and multiplexing efficiency
Solution Approach 2:
The patent introduces a new mapping dimension by defining the relationship between eREGs, eCCEs, and PRBs through specific mapping rules. This dimensional organization allows distributed E-PDCCH to achieve frequency diversity while localized E-PDCCH maintains high multiplexing efficiency by selecting appropriate eCCEs for transmission
2Productivity
If multiple UEs are transmitted with different E-PDCCH modes using the same resource, then resource utilization is improved, but interference between different modes increases
Solution Approach 1:
The patent applies local quality by allowing different portions of the resource structure to serve different purposes. Localized eCCEs can be allocated to localized E-PDCCH for high-efficiency transmission, while distributed eCCEs are allocated to distributed E-PDCCH for frequency diversity. This localized differentiation reduces inter-mode interference while maintaining high resource utilization
Solution Approach 2:
The patent introduces eCCE as an intermediary layer between eREGs and PRBs. This intermediary structure enables flexible allocation and isolation of resources for different E-PDCCH modes, allowing the system to manage interference while maintaining resource utilization
Data Source
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AI summary
The present invention provides methods for transmitting and receiving a control channel, a base station, and a user equipment. The method for transmitting a control channel includes: determining m PRB pairs used for transmitting a control channel to be transmitted; when a distributed transmission mode is used for transmission, determining an aggregation level L of the control channel to be transmitted; determining, according to the aggregation level L, a first control channel candidate at the aggregation level L; and placing, on physical resources to which the first control channel candidate is mapped, control information of the control channel to be transmitted, and transmitting the control information. In the present invention, at the aggregation level L, when some eREGs of any control channel candidate of a distributed control channel to be transmitted are mapped to a PRB pair, these eREGs are preferably mapped to physical resources corresponding to fewest localized eCCEs in the PRB pair, thereby improving multiplexing efficiency of control channels of different modes.