Dynamic Control Region Sizing for LTE Subframes
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Solution Overview
Problem
In LTE systems, the fixed size of the control region in downlink subframes can lead to suboptimal performance due to interference and resource competition between control and data channels, as it does not adapt to varying data region loads, potentially degrading throughput.
Innovation Solution
A method for dynamically selecting the size of the control region in each downlink subframe based on both the initial size and the data region load, allowing the final size to be greater than or equal to the initial size, ensuring optimal resource allocation and minimizing interference.
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 data region size decreases reducing DL-SCH throughput
Solution Approach 1:
The patent implements dynamic control region size adaptation by introducing a data region load indicator that triggers different control region configurations. When data region load is below a threshold, the control region is expanded to accommodate more PDCCHs; when load is high, the control region is reduced to preserve data region capacity. This dynamic adjustment resolves the contradiction by making the control region size flexible rather than fixed, allowing the system to optimize the trade-off between control channel capacity and data throughput based on real-time conditions.
Solution Approach 2:
The patent changes the parameter of control region size (number of OFDM symbols) based on data region load conditions. By introducing a load-dependent parameter adjustment mechanism, the system can vary the control region size between 1-3 symbols depending on whether data region load is below or above a threshold. This parameter change approach allows the system to adapt to varying traffic conditions and resolve the resource allocation contradiction.
2Productivity
If the control region size is decreased to increase data region capacity, then DL-SCH throughput is improved, but the control channel may not accommodate all required PDCCHs
Solution Approach 1:
The system dynamically adjusts control region size based on data region load indicators. When data load is low, the control region is expanded to ensure all PDCCHs can be accommodated. When data load is high, the control region is reduced to maximize data throughput. This dynamic behavior ensures that the system maintains adequate control channel capacity only when necessary, resolving the contradiction between control capacity and data throughput.
Solution Approach 2:
The control region size parameter is changed based on data region load conditions. The system uses a threshold-based mechanism where the control region size parameter switches between different values (1, 2, or 3 symbols) depending on whether data region load is below or above the threshold, ensuring optimal balance between control and data capacities.
3Device complexity
If a fixed control region size is used, then system complexity is reduced, but resource utilization efficiency deteriorates under varying load conditions
Solution Approach 1:
The patent introduces dynamic adaptation of control region size based on data region load, transforming the fixed-size system into a flexible one. The system monitors data region load and adjusts control region configuration accordingly, improving resource utilization efficiency without requiring complex machine learning or optimization algorithms. This moderate dynamic approach resolves the contradiction by adding only the necessary complexity for load-based adaptation.
Solution Approach 2:
The system changes the control region size parameter based on data region load conditions, using a simple threshold-based decision mechanism. This parameter change approach improves resource utilization efficiency under varying load conditions while maintaining relatively simple system complexity, as the adjustment logic is based on straightforward load comparison rather than complex optimization.
Data Source
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Figure 3A~3C
AI summary
A system, method (400), and network node (102) is presented for setting the size of a control region, the PDCCH region (201) of a subframe (200). The PDCCH control region may have a size, indicated by the Control Format Indicator, CFI, transmitted on the PCFICH, that varies between 1 and 3 OFDM symbols. The network node (102) may select (402) an initial size for the control region (201), and determine (404) whether the initial size for the control region is less than a predetermined maximum control region size. In response to determining that the initial size is less than the predetermined maximum control region size, the network node (102) selects (406) a final size for the control region (201) based on a data region load. The data region load indicates a load on all physical downlink shared channels, PDSCHs, on all enhanced PDCCHs, ePDCCHs, in the data region. After selecting the final size for the control region, the network node (102) transmits (408) the subframe (200), wherein the control region of the subframe comprises information identifying the selected final size, and the size of the control region is equal to the selected final size.