Radio Base Station Downlink Control Channel Capacity Expansion
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Solution Overview
Problem
In next-generation radio communication systems like LTE-A, the downlink control channel capacity is insufficient to support the increasing number of users, leading to a shortage of resources for allocating downlink control information, which affects the throughput performance of MU-MIMO transmission.
Innovation Solution
The proposed solution involves expanding the downlink control channel by using a frequency division multiplexing-type PDCCH (FDM-type PDCCH) in the radio resources beyond the conventional PDCCH region, allowing for the transmission of downlink control signals and data signals to be time-division-multiplexed, and utilizing user-specific reference signals for channel estimation and demodulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of users connected to the base station is increased to support MU-MIMO transmission, then the spectral efficiency and data rate are improved, but the downlink control channel capacity becomes insufficient
Solution Approach 1:
The patent extends the PDCCH region from the traditional first few symbols of the subframe into the data region, utilizing the time dimension beyond the conventional control region boundaries. This allows control information to be transmitted in both the control region (first L symbols) and the data region (remaining symbols), effectively increasing control channel capacity without limiting spectral efficiency
Solution Approach 2:
The patent divides control information transmission into two segments: control information for some users transmitted in the control region (first L symbols), and control information for other users transmitted in the data region (remaining symbols after L). This segmentation allows the system to support more users by distributing control information across different time regions
2Quantity of substance
If the PDCCH region is extended to increase control channel capacity, then more downlink control information can be multiplexed, but the device complexity and resource allocation complexity increase
Solution Approach 1:
The patent introduces a configurable parameter L (number of symbols for control region) that can be dynamically adjusted based on system conditions and user requirements. This dynamic configuration allows the system to adapt the control region size, balancing control channel capacity needs against resource allocation complexity and spectral efficiency requirements
Solution Approach 2:
The patent performs preliminary configuration of the control region size (parameter L) and control information allocation strategy before actual data transmission. By pre-determining which users receive control information in the control region versus the data region, the system reduces real-time processing complexity while maintaining increased control channel capacity
Data Source
AI summary
The present invention is designed to provide a radio base station apparatus, a mobile terminal apparatus, a radio communication system and a radio communication method which can cope with an increased number of users. A radio base station apparatus is provided with: a signal generating section that generates a first downlink control signal and a second downlink control signal for a mobile terminal apparatus; a first multiplexing section that multiplexes the first downlink control signal on a control region up to a predetermined number of symbols from the top of a subframe; a second multiplexing section that frequency-division-multiplexes the second downlink control signal on radio resources from the next symbol in the control region to the last symbol of the subframe; and a transmission section that transmits the first downlink control signal multiplexed on the control region and the second downlink control signal multiplexed on the radio resources.