Dynamic Control Region Sizing for LTE Downlink Subframes
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Solution Overview
Problem
In LTE radio communication systems, a fixed control region size for downlink subframes is suboptimal as it either reduces downlink peak throughput by stealing resources from data channels or fails to carry all control channel assignments, leading to degraded throughput.
Innovation Solution
A method for dynamically selecting the size of the control region for each downlink subframe based on the number and priority of physical downlink control channels (PDCCHs), allowing adaptation to varying traffic scenarios and optimizing resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed control region size is used for downlink subframes, then the control region can carry all required PDCCH assignments, but the downlink peak throughput is reduced due to resource theft from data channels
Solution Approach 1:
The control region size is made dynamic rather than fixed. The base station determines the actual number of PDCCH assignments needed for each subframe and adjusts the control region size accordingly. This allows the system to adapt to varying traffic conditions, using minimal control region resources when few assignments are needed and expanding when more assignments are required, thereby optimizing the balance between control capacity and data throughput.
Solution Approach 2:
The patent changes the parameter of control region size from a fixed value to a variable value that depends on the number of PDCCH assignments. By making the control region size a function of the actual assignment requirements, the system can adjust this critical parameter in real-time to match traffic conditions, resolving the contradiction between ensuring sufficient control capacity and maximizing data throughput.
2Reliability
If a large control region size is used to carry all PDCCH assignments, then all DL and UL assignments can be transmitted, but the available capacity for DL-SCH is reduced
Solution Approach 1:
Instead of always allocating the maximum possible control region size, the system applies partial action by allocating only the necessary amount. The base station calculates the exact number of PDCCH assignments needed and allocates the control region accordingly. This avoids excessive allocation of control resources when fewer assignments are needed, thereby preserving more resources for data channels while still ensuring all required assignments can be transmitted.
3Productivity
If a small control region size is used to maximize DL-SCH capacity, then peak throughput is improved, but not all PDCCH assignments can be carried
Solution Approach 1:
The control region size dynamically adapts to the actual assignment requirements. When traffic conditions require fewer PDCCH assignments, the control region is kept small to maximize data throughput. When more assignments are needed, the control region expands to ensure all assignments can be carried. This dynamic adjustment resolves the contradiction by making the control region size responsive to actual needs rather than fixed at an suboptimal value.
Data Source
AI summary
Disclosed herein are systems and methods for choosing the size of the control region of a downlink subframe. For example, an apparatus for selecting the size of the control region based on a set of one or more physical downlink control channels (PDCCHs) is disclosed. The apparatus, in some embodiments, includes: a module configured to determine, for each of at least two or more control region sizes included in a set of two or more control region sizes, a subset of PDCCHs from said set of PDCCHs that can be assigned to a control region having a size equal to the control region size; and control region size selector for selecting a control region size for the subframe, wherein the control region size selector is configured to make the selection based, at least in part, on information pertaining to the subset of PDCCHs that can be assigned to a control region having a size equal to the selected control region size.