Timing Dependent Search Space Configuration for MTC Devices
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Solution Overview
Problem
Wireless communication networks face challenges in efficiently managing radio transmissions with varying timing requirements, particularly in scenarios requiring low latency, where the blind decoding process for downlink control information can cause excessive delay.
Innovation Solution
The implementation of multiple search spaces within the time-frequency grid for radio transmissions, where a second search space is configured to start earlier and have a shorter duration than a first search space, allowing for reduced latency and efficient resource utilization, tailored to specific timing requirements of radio devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a single search space is used for downlink control information, then device complexity is reduced, but latency increases for devices with strict timing requirements
Solution Approach 1:
The patent divides the search space into multiple distinct search spaces (first search space and second search space) with different time-frequency configurations. Each search space is optimized for specific timing requirements, allowing devices to select the appropriate search space based on their latency needs without increasing overall system complexity.
Solution Approach 2:
The patent introduces dynamic search space configuration where the second search space can be adaptively configured with shorter duration and different time coordinates based on device category and timing requirements. This dynamic adaptation allows the system to optimize for low latency when needed while maintaining flexibility for other devices.
2Loss of time
If the search space duration is shortened to reduce latency, then timing requirements are met, but the quantity of control information that can be transmitted is reduced
Solution Approach 1:
The patent compensates for the reduced time dimension in the second search space by expanding into the frequency dimension. The second search space is configured with shorter time duration but can utilize different frequency resources, maintaining overall control information capacity while achieving lower latency for time-critical devices.
Solution Approach 2:
Different search spaces are assigned different quality characteristics tailored to specific device needs. The second search space has optimized local properties (shorter duration, specific time coordinates) for low-latency devices, while the first search space maintains standard properties for other devices, allowing each to operate at optimal performance.
3Adaptability or versatility
If multiple search spaces are configured for different device categories, then adaptability is improved, but device complexity increases
Solution Approach 1:
The system dynamically configures the second search space based on device category information. Devices self-identify their category and timing requirements, and the network configures appropriate search spaces accordingly. This dynamic approach provides high adaptability while keeping device complexity manageable through automated configuration.
Solution Approach 2:
Devices autonomously determine their timing requirements and select or receive configuration for the appropriate search space based on their category. This self-service mechanism reduces the need for complex centralized management and allows devices to adapt to their own needs without increasing overall system complexity.
Data Source
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AI summary
An access node of the wireless communication network determines a configuration of a first search space (210) in terms of first time domain coordinates and first frequency domain coordinates of a time-frequency grid of radio resource elements. Further, the access node determines a configuration of a second search space (220) in terms of second time coordinates and second frequency domain coordinates of the time-frequency grid. The second search space (220) differs from the first search space at least with respect to the time domain coordinates. In radio resource elements of the first search space (210), the access node transmits downlink control information for a first class of radio devices subject to a first timing requirement. In radio resource elements of the second search space (220), the access node transmits downlink control information for a second class of radio devices subject to a second timing requirement which is stricter than the first timing requirement.