PDCCH Frequency-Division Multiplexing in LTE-Advanced
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Solution Overview
Problem
In future mobile communication systems, such as LTE-Advanced, the conventional radio resource allocation method fails to optimize the efficiency of radio resource usage as the number of user terminals multiplexed over the same resources increases, particularly in Hetnets and CoMP transmissions.
Innovation Solution
A user terminal and radio base station employ a method where the downlink control channel and shared channel are frequency-division-multiplexed in a resource region, with the user terminal detecting the starting position of this multiplexing to receive the control channel effectively, thereby extending the PDCCH allocation region without disrupting the existing PDCCH region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of user terminals multiplexed over the same radio resources is increased, then the efficiency of radio resource usage is improved, but the conventional radio resource allocation method cannot optimize the efficiency effectively
Solution Approach 1:
The patent extends the PDCCH allocation into the PDSCH region by frequency-division multiplexing, adding a spatial dimension to control channel allocation. This allows the control channel to utilize frequency resources in the data region, effectively increasing the multiplexing capacity without conflicting with existing time-domain allocations.
Solution Approach 2:
The patent segments the PDSCH region by allocating specific frequency resources within it for PDCCH transmission. This segmentation creates dedicated control channel resources embedded within the data region, enabling independent control channel allocation that supports increased user terminal multiplexing.
2Quantity of substance
If the PDCCH allocation region is extended to support more user terminals, then the multiplexing capacity is improved, but the existing PDCCH region may be disrupted
Solution Approach 1:
The patent segments the PDSCH region to create embedded PDCCH resources, separating control and data functions within the same time-frequency grid. This segmentation allows extension of control channel capacity without interfering with the traditional PDCCH region structure.
Solution Approach 2:
The patent introduces frequency-division multiplexing as an intermediary mechanism between the PDCCH and PDSCH. This intermediary approach allows both control and data channels to coexist in the same time domain by separating them in the frequency domain, maintaining reliability while extending capacity.
3Productivity
If frequency-division multiplexing is applied in the PDSCH region, then the control channel capacity is increased, but the detection complexity at the user terminal increases
Solution Approach 1:
The patent applies preliminary action by pre-signalizing the starting position of frequency-division multiplexed PDCCH resources to user terminals. This advance notification allows terminals to prepare their detection algorithms and allocate processing resources efficiently, reducing the actual detection complexity during data reception.
Solution Approach 2:
The patent implements feedback mechanisms where the base station provides information about the starting position of multiplexed control channels to user terminals. This feedback enables terminals to accurately locate and decode control channel resources without exhaustive search, significantly reducing detection complexity.
Data Source
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AI summary
The present invention is designed such that it is possible to optimize the effect of improving the efficiency of use of radio resources even when the number of user terminals to be multiplexed over the same radio resources is further increased. A user terminal performs downlink communication with a radio base station using a PDCCH resource region and a PDSCH resource region. The user terminal detects the starting position of the radio resources where the PDSCH and the PDCCH are frequency-division-multiplexed in the PDSCH resource region in the time direction, and receives the PDCCH that is frequency-division-multiplexed over the radio resources starting from the detected starting position.