Distributed Downlink Control Channel Allocation for Capacity Expansion
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Solution Overview
Problem
Conventional radio resource allocation configurations in next-generation mobile communication systems, such as LTE-A, face challenges in optimizing performance for multi-user MIMO transmission, particularly in heterogeneous networks and CoMP scenarios, due to increased user connectivity and limited downlink control channel capacity.
Innovation Solution
A base station apparatus that allocates downlink control signals in a distributed manner across virtual resources in both low and high frequency bands, using enhanced PDCCH and DM-RS, to expand the control channel capacity and reduce the impact of fading and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of users connected to the base station is increased to support future systems like MU-MIMO transmission, then the system capacity and spectral efficiency are improved, but the conventional radio resource allocation configuration cannot derive optimal performance due to limited downlink control channel capacity
Solution Approach 1:
The patent introduces a new dimension of frequency resource allocation by mapping virtual resource blocks to physical resource blocks in a distributed manner across different frequency bands. This dimensional transformation allows the control channel to utilize both low and high frequency bands, effectively doubling the available control channel capacity without increasing the traditional control region size.
Solution Approach 2:
The patent segments the downlink control channel into multiple virtual resource blocks that are distributed across different physical resource blocks in the frequency domain. This segmentation allows the control information to be spread across multiple frequency locations, enabling the system to serve more users simultaneously while maintaining control signal reliability.
2Device complexity
If downlink control signals are allocated in a concentrated manner within a limited frequency range, then the allocation is simple, but the influence of fading variation and interference from other cells increases
Solution Approach 1:
The patent applies local quality by assigning different frequency locations (low and high frequency bands) to different virtual resource blocks. This creates spatial diversity in the frequency domain, where each local frequency region experiences different fading characteristics. By distributing control signals across these diverse frequency locations, the system reduces the impact of fading variation and interference at any single location.
Solution Approach 2:
The patent converts the harmful effect of frequency-selective fading into a beneficial diversity effect. Instead of avoiding frequency variations, the system deliberately exploits them by distributing control signals across frequency blocks that experience different fading conditions. This transforms the harmful fading variation into a beneficial diversity gain, improving overall signal reliability.
Data Source
AI summary
The present invention is designed to provide a base station apparatus, a mobile terminal apparatus, a communication system and a communication method that cope with the shortage of downlink control channel capacity. For a mobile terminal apparatus that receives downlink signals using a resource region for downlink control signals and a resource region for downlink data signals, a base station apparatus is configured to set a plurality of virtual resources for downlink control signals in a plurality of physical resources that are arranged in a frequency direction in the resource region for downlink data signals, and allocate the downlink control signals, in a distributed manner, between virtual resources of a relatively low frequency band side and virtual resources of a relatively high frequency band side in a plurality of virtual resources.