Downlink Control Channel Resource Allocation via Feedback
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Solution Overview
Problem
In LTE wireless communication systems, the limited capacity of physical downlink control channels (PDCCH) restricts the number of control channels that can be transmitted, especially in systems with a large number of devices using low-rate services like VoIP, due to the limited size of the control region, leading to inefficiencies in radio resource allocation.
Innovation Solution
A method and system that determine radio resources for allocation to downlink control channels by analyzing channel quality reports from wireless devices, identifying subbands with low variance and high average channel quality, and reconfiguring resource allocation to improve efficiency, allowing for increased control channel capacity and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the control region size is increased to accommodate more PDCCHs, then the control channel capacity is improved, but the available data region is reduced and system complexity increases
Solution Approach 1:
The patent divides the control channel resources into multiple ePDCCH sets, each occupying different frequency resources within the data region. This segmentation allows multiple control channels to be transmitted simultaneously without increasing the overall control region size, thereby increasing control channel capacity while maintaining system complexity at acceptable levels.
Solution Approach 2:
The patent transitions from the traditional time-domain control region to frequency-domain resource allocation within the data region. By utilizing the frequency dimension for ePDCCH transmission, the system can accommodate more control channels without expanding the control region vertically in time, thus increasing capacity without proportionally increasing system complexity.
2Adaptability or versatility
If ePDCCH resources are allocated dynamically on specific frequencies, then control channel flexibility is improved, but channel quality variability increases
Solution Approach 1:
The patent implements a feedback mechanism where the network node receives channel quality reports from wireless devices and uses this feedback to determine the variance and average channel quality of different subbands. This feedback loop enables the system to adapt resource allocation dynamically while maintaining reliability by selecting subbands with stable and high channel quality.
Solution Approach 2:
The patent changes the allocation parameters based on channel quality metrics. By calculating variance and average channel quality for different subbands and adjusting resource allocation accordingly, the system maintains flexibility in dynamic allocation while ensuring reliability by preferring subbands with lower variance and higher average quality.
3Productivity
If channel quality analysis and resource reconfiguration are performed frequently, then resource allocation efficiency is improved, but processing overhead increases
Solution Approach 1:
The patent performs channel quality analysis over a predetermined measurement period before making resource allocation decisions. This preliminary action approach allows the system to gather sufficient data to make informed allocation decisions without reacting too frequently, thereby improving resource allocation efficiency while avoiding excessive processing overhead from continuous reconfiguration.
Data Source
AI summary
A method and network node for determining radio resources for allocation to a downlink control channel in a communication network are disclosed. According to one aspect, a method includes receiving, over a predetermined measurement period, a plurality of reports from a wireless device, each report being indicative of a channel quality within at least a subband of an available bandwidth of the communication network. The method further includes for each subband for which at least one report has been received, determining a variance of the channel quality and an average of the channel quality over the predetermined measurement period. The method further includes determining subbands having at least a variance of the channel quality less than a first threshold.