Downlink Control Information Processing for Coverage Gain
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Solution Overview
Problem
LTE small cells face challenges in enhancing downlink coverage due to limitations in increasing transmit power and the number of antennas, and existing methods like MTC physical downlink control channel (MPDCCH) and time domain repetition increase processing delay and complexity.
Innovation Solution
A method that involves determining predefined search spaces based on aggregation levels supported by terminals, allowing blind detection of downlink control information (DCI) in specific search spaces, and using frequency-domain data merging to enhance coverage without increasing hardware complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If downlink transmit power is increased to enhance coverage, then coverage gain is improved, but hardware complexity and cost increase
Solution Approach 1:
The patent merges frequency-domain resources by combining multiple Physical Downlink Control Channels (PDCCH) transmitted on different frequency resources into a single logical channel. This allows the terminal to accumulate signal energy across frequency diversity without requiring increased transmit power or additional hardware antennas, thereby improving coverage while avoiding hardware complexity increases.
Solution Approach 2:
The patent transitions from time-domain repetition (TTI bundling) to frequency-domain resource merging, changing the dimension of diversity from time to frequency. This approach achieves coverage enhancement by utilizing frequency diversity resources rather than repeating transmissions over time, reducing processing delay while maintaining coverage improvement.
2Reliability
If time domain repetition is used to obtain coverage gain, then coverage is enhanced, but data processing delay increases and throughput rate decreases
Solution Approach 1:
The patent shifts from time-domain repetition to frequency-domain resource merging, utilizing frequency diversity instead of temporal repetition. This allows the terminal to combine PDCCH candidates from multiple frequency resources within the same time interval, achieving coverage enhancement without increasing processing delay or reducing throughput rate.
3Reliability
If MTC physical downlink control channel (MPDCCH) is used for coverage enhancement, then coverage gain is achieved, but terminal adaptability decreases and operation difficulty increases
Solution Approach 1:
The patent creates a universal PDCCH merging mechanism that can be applied to all terminals regardless of whether they support MPDCCH or not. By merging frequency-domain PDCCH resources using existing terminal capabilities, the solution provides coverage enhancement with broad adaptability across different terminal types without requiring specialized hardware or complex operational procedures.
Data Source
AI summary
This application provides a downlink control information (DCI) obtaining method and apparatus. The method includes: determining, by a terminal, predefined search space based on aggregation levels supported by the terminal, where the predefined search space includes search space corresponding to at least one of an aggregation level 16 and an aggregation level 24; and performing, blind detection to obtain the DCI. Alternatively, the method includes: determining, by a terminal, blind detection search space of the terminal from predefined search space based on a quantity of resource blocks (RBs) occupied by an enhanced physical downlink control channel (EPDCCH) and aggregation levels supported by the terminal, where the predefined search space includes corresponding search space obtained when the RB quantity is 16; and performing, blind detection to obtain the DCI. According to this application, a downlink coverage gain can be increased, and diversity of implementations of downlink coverage enhancement can be improved.