Wireless Search Space Grid for Narrowband MTC Reliability
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Solution Overview
Problem
Current wireless telecommunications systems face challenges in providing coverage enhancement for machine-type communication (MTC) devices with narrowband operations, as repeated transmission approaches increase receiver complexity and hardware requirements, limiting the ability to support repetitions in the frequency domain.
Innovation Solution
A wireless telecommunications system that selectively transmits messages with multiple repetitions over a search space grid of radio resources, where the arrangement of candidates within the search space is determined based on the number of message buffers and repetition levels, allowing the terminal device to efficiently decode messages with reduced hardware complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If repeated transmissions are used to provide coverage extension, then the likelihood of successful message decoding is enhanced, but receiver complexity and hardware requirements increase
Solution Approach 1:
The search space is segmented into multiple search space sets, each with different repetition levels. The terminal device can selectively search for messages with different repetition levels in different search space sets, allowing the receiver to handle repetitions in a structured manner that reduces complexity while maintaining reliability.
Solution Approach 2:
The patent introduces a new dimension for organizing repetitions by arranging them in both time and frequency domains within the search space grid. This multi-dimensional arrangement allows the terminal device to efficiently process repetitions without requiring proportional increases in hardware complexity, as the structure provides natural organization points for processing.
2Reliability
If repeated transmissions are used for coverage enhancement, then message decoding reliability improves, but hardware requirements increase
Solution Approach 1:
The network can dynamically configure the number of search space sets and their associated repetition levels based on terminal device capabilities and channel conditions. This dynamic configuration allows the system to adapt to different hardware capabilities, enabling reliable communication without requiring all terminals to support the maximum hardware complexity.
Solution Approach 2:
The patent changes the parameter of search space organization from a single uniform structure to multiple configurable search space sets with different repetition levels. This parameter change allows the system to optimize for different hardware capabilities while maintaining message decoding reliability through appropriate selection of repetition levels.
3Device complexity
If narrowband operations are used for MTC devices, then cost is reduced, but the ability to support repetitions in the frequency domain is limited
Solution Approach 1:
The patent compensates for the limited frequency domain resources in narrowband operations by introducing a time dimension to the search space structure. Multiple search space sets are arranged in time, allowing repetitions to be supported across different time instances within the narrowband, thus maintaining adaptability for repetitions without requiring wider bandwidth.
Solution Approach 2:
The search space is segmented into multiple sets that can be configured with different repetition levels. This segmentation allows narrowband devices to support repetitions by distributing them across multiple time instances in different search space sets, rather than requiring simultaneous frequency domain resources.
4Adaptability or versatility
If multiple search space sets with different repetition levels are arranged in a search space grid, then flexible scheduling is enabled, but the arrangement complexity increases
Solution Approach 1:
Different search space sets are assigned different local qualities in terms of repetition levels and resource allocations. This local differentiation allows flexible scheduling for different message types and channel conditions while maintaining a regular overall grid structure that simplifies the arrangement rules. Each local region of the search space can be optimized independently according to specific requirements.
Data Source
AI summary
A wireless telecommunications system comprises a network infrastructure equipment, and a terminal device configured to communicate over a radio interface that supports a downlink channel for conveying a message from the network infrastructure equipment to the terminal device. The network infrastructure equipment is configured to selectively transmit the message with a number of repetitions. The message is transmitted on radio resources selected by the network infrastructure equipment from a plurality of candidates for radio resources that define a search space for the terminal device to search for the message. The plurality of candidates comprise candidates associated with a number, N, of different repetition levels for the transmission of a message. Different repetition levels correspond with different numbers of repetitions for the transmission of a message.