Downlink Control Signal Allocation in Mobile Systems
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Solution Overview
Problem
Current multi-carrier mobile communication systems lack a clear method for efficiently transmitting downlink control signals alongside downlink data packets using localized and distributed allocation schemes, which hampers the transmission of scheduling information for uplink and downlink data.
Innovation Solution
A method and structure for transmitting downlink control signals that dynamically switch between localized and distributed allocation based on the characteristics of the downlink data transmission, using distributed allocation for scheduling signals in one OFDM symbol interval and localized allocation in subsequent intervals, allowing flexible multiplexing and efficient resource usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distributed allocation is used for downlink control signal transmission, then frequency diversity gain is obtained and reception performance is enhanced, but transmission efficiency and adaptability to different control signal sizes are reduced
Solution Approach 1:
The downlink control signal transmission is segmented into two parts: a first downlink control signal transmitted via distributed allocation for frequency diversity, and a second downlink control signal transmitted via localized allocation for transmission efficiency. This segmentation allows each part to leverage the strengths of its allocation method while mitigating the weaknesses.
Solution Approach 2:
Different allocation methods are applied to different portions of control signal information based on local requirements. The first control signal carries general scheduling information benefiting from distributed allocation, while the second control signal carries UE-specific information benefiting from localized allocation, optimizing overall system performance.
2Productivity
If localized allocation is used for downlink control signal transmission, then transmission efficiency is improved, but frequency diversity gain and reception performance are reduced
Solution Approach 1:
The control signal transmission is divided into two segments with different allocation strategies. The first segment uses distributed allocation to ensure reliable reception through frequency diversity, while the second segment uses localized allocation to achieve efficient transmission with minimal overhead.
Solution Approach 2:
The patent employs asymmetric allocation where the first downlink control signal uses distributed allocation across multiple resource blocks, while the second downlink control signal uses localized allocation in specific resource blocks, creating an asymmetric structure that balances reliability and efficiency.
3Device complexity
If a single allocation method is used for all downlink control signals, then system complexity is reduced, but adaptability to different control signal sizes and transmission scenarios is limited
Solution Approach 1:
The patent creates a universal downlink control signal structure that can adapt to different transmission scenarios and control signal sizes by combining two allocation methods. This multi-functional approach allows the system to handle various UE conditions and scheduling requirements within a unified framework.
Solution Approach 2:
The system dynamically selects which downlink control signal (first or second) to transmit based on current transmission requirements, control signal size, and channel conditions. This dynamic adaptation allows the system to optimize performance for different scenarios without increasing fundamental system complexity.
Data Source
Figure 1~2A
Figure 2B~3A
Figure 3B~4
AI summary
Methods for transmitting a downlink control signal are disclosed, by which localized allocation and distributed allocation are efficiently used in transmitting a downlink control signal. One of the methods includes multiplexing the downlink control signal in a manner of if there exists downlink data transmission to a prescribed user equipment (UE), applying localized allocatio to a transmission of the downlink control signal including the scheduling information on the uplink data transmission of the UE and applying distributed allocation to another transmission of the downlink control signal and transmitting the multiplexed downlink control signal.