Search Space Configuration for MTC Downlink Control Channels
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Solution Overview
Problem
Existing LTE/LTE-A systems face challenges in determining the optimal quantity and positions of Search Spaces (SSs) for low-cost and coverage enhancement Machine Type Communication (MTC) terminals, leading to inefficient resource utilization and potential large delays in data transmission.
Innovation Solution
A method and device that determine one or more SS positions based on coverage levels and message types, allowing for efficient resource allocation by configuring different SS positions for various coverage enhancement levels and message types, ensuring sufficient resource usage for scheduling common messages and avoiding delays caused by time-sharing transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single Common Search Space (CSS) is used for all coverage enhancement terminals, then resource configuration is simple, but transmission delays increase due to time-sharing transmission requirements
Solution Approach 1:
The patent segments the Common Search Space into multiple CSS sets (first CSS set and second CSS set) based on coverage enhancement levels. Terminals in different coverage levels can simultaneously monitor their respective CSS sets without time-sharing, thereby reducing transmission delays while maintaining configuration simplicity through standardized set structures.
2Reliability
If Search Space resources are allocated for coverage enhancement terminals, then coverage performance improves, but resource utilization efficiency decreases
Solution Approach 1:
The patent applies local quality by configuring different CSS sets with specific aggregation levels and candidate quantities tailored to different coverage enhancement levels. This allows optimized resource allocation for each terminal type while maintaining overall system efficiency, as each terminal monitors only its designated CSS set rather than all possible candidates.
3Adaptability or versatility
If multiple Search Space positions are configured for different message types, then scheduling flexibility increases, but terminal processing complexity increases
Solution Approach 1:
The patent segments different message types (RAR, paging, random access preamble) into different CSS sets with specific monitoring configurations. Terminals process only the relevant CSS set for their current operation state, maintaining low processing complexity while achieving high scheduling flexibility through the standardized segmentation framework.
Data Source
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AI summary
Disclosed are a method and an apparatus for sending and receiving a downlink control channel. The method comprises: a base station determines position(s) of one or more search spaces according to at least one of a coverage level and a message type, and sends a downlink control channel in the search space, the coverage level comprising at least a non-coverage enhanced level (CE0) and coverage enhanced levels (CE1, CE2, CE3), the message type comprising at least random access response (RAR), paging, radio resource control (RRC), and transmission power control (TPC); the search space comprising: a collective search space (CSS), a dedicated search space (dedicated SS), and a non-user search space (non-USS); and the position of the search space comprising: a narrow-band/frequency domain position, a time domain position, and an aggregation position.