Pico eNB Downlink Control Information Interference Protection
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Solution Overview
Problem
In heterogeneous wireless communication networks, high-power macro eNBs cause interference to low-power pico eNBs, leading to challenges in correctly demodulating downlink control information, especially for system broadcast messages and paging messages, due to strong interference.
Innovation Solution
A method where the serving node of an interfered cell determines specific resources, such as physical resources in UE-specific search spaces or extended common search spaces, to transmit downlink control information, including scheduling information for paging messages and SIB1, on physical downlink shared channels, thereby reducing interference by separating these transmissions from those of the interfering cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If time division multiplexing is used to separate transmissions in different subframes, then interference for scheduled UEs is reduced, but system broadcast messages and paging messages still experience strong interference
Solution Approach 1:
The patent segments the transmission resources for different types of downlink control information. Common search space resources are specifically allocated and protected from macro eNB interference, while other resources follow TDM patterns. This segmentation allows system broadcast messages and paging messages to be transmitted on protected resources that are not subject to macro eNB interference, resolving the contradiction between reducing interference for scheduled UEs and ensuring reliable delivery of critical broadcast messages.
Solution Approach 2:
The patent applies different transmission strategies to different types of downlink control information based on their specific requirements. Common search space resources used for system broadcast messages and paging messages are given special protection (local quality enhancement) by excluding them from macro eNB transmission, while other resources can follow standard TDM patterns. This local quality approach ensures that critical messages receive the interference protection they need without sacrificing overall system efficiency.
2Power
If macro eNB transmits at high power to maintain its coverage, then macro cell performance is maintained, but interference to pico eNB downlink control information increases
Solution Approach 1:
The patent extracts common search space resources from the set of resources subject to macro eNB transmission. By identifying and separating these specific resources used for system broadcast messages and paging messages, the patent removes them from the interference zone created by macro eNB high-power transmissions. This allows macro eNB to maintain high transmission power for coverage while extracted protected resources remain interference-free for pico eNB critical messages.
Solution Approach 2:
The patent introduces protected common search space resources as an intermediary layer between macro eNB and pico eNB transmissions. These intermediary resources serve as a buffer zone where pico eNB can transmit critical downlink control information without being affected by macro eNB high-power transmissions, enabling both macro and pico cells to operate at optimal power levels simultaneously.
Data Source
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AI summary
The invention discloses a method for transmitting and receiving downlink control information, a serving node and a user equipment. The method comprises: determining, by a serving node of a interfered UE, a protected resource, wherein the protected resource is located in at least one of the followings: a physical resource corresponding to a USS in a PDCCH, a physical resource corresponding to an expanded CSS in the PDCCH, a physical resource corresponding to a USS in an E-PDCCH or a physical resource corresponding to a CSS of the E-PDCCH; transmitting, by the serving node, first downlink control information of an interfered cell on the protected resource, wherein the first downlink control information comprises scheduling information for scheduling a paging message and/or a SIB1 message of the interfered cell. The invention can reduce the interference to a system broadcast message, a paging message and the like in a heterogeneous network.