RedCap NR Random Access Using Dedicated Search Spaces and CORESETs
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently supporting terminals with reduced capabilities, such as RedCap UEs, in accessing and obtaining system information due to their limited performance compared to general smartphones.
Innovation Solution
A method and apparatus for RedCap UEs to receive System Information Block1, determine preamble formats and subframes based on specific configurations, and transmit preambles using dedicated search spaces and control resource sets to facilitate NR cell access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If RedCap UE uses standard 5G NR access procedures, then compatibility with existing systems is maintained, but bandwidth and processing resource requirements exceed RedCap UE capabilities
Solution Approach 1:
The patent segments the system information blocks into multiple parts (MIB, SIB1, SIB2, etc.) and transmits them through different channels and time periods. RedCap UE can receive only the essential information needed for basic operations, reducing the total quantity of information processing required while maintaining compatibility with the overall 5G NR system structure.
Solution Approach 2:
The patent extracts and separates RedCap-specific configuration parameters from the standard 5G NR configuration. By defining dedicated RACH-ConfigCommon and PDCCH configuration parameters for RedCap UE, the system reduces the processing burden on RedCap devices by only requiring them to interpret and use the relevant subset of parameters rather than the complete standard specification.
2Loss of information
If RedCap UE receives all system information blocks, then complete system information is obtained, but power consumption and processing complexity increase beyond RedCap UE capabilities
Solution Approach 1:
The patent implements partial action by enabling RedCap UE to receive only the minimum necessary system information required for basic cell access and operation. Rather than requiring complete reception of all system information blocks, the RedCap UE can operate with a subset of information, reducing processing complexity while maintaining sufficient functionality for reduced-capability operations.
Solution Approach 2:
The patent applies preliminary action by providing RedCap-specific configuration parameters in advance through dedicated information elements. The RACH-ConfigCommon and PDCCH configuration parameters are pre-configured for RedCap UE capabilities, allowing devices to perform basic operations without needing to process and interpret the complete standard specification, thereby reducing processing complexity before the device even attempts to access the network.
3Reliability
If RedCap UE monitors all search spaces and control resource sets, then all control information is received, but bandwidth consumption and processing load exceed RedCap UE limits
Solution Approach 1:
The patent applies local quality by defining specific, dedicated search spaces and control resource sets tailored for RedCap UE rather than requiring monitoring of all possible search spaces. The configuration parameters (searchSpaceZero, commonSearchSpaceList, ra-SearchSpace) are locally optimized for RedCap capabilities, ensuring reliable reception of essential control information while consuming fewer bandwidth resources compared to full-compliance UEs.
4Adaptability or versatility
If standard RACH procedures are used for RedCap UE, then universal access protocol is maintained, but access latency and resource conflict increase for reduced capability terminals
Solution Approach 1:
The patent enables self-service by allowing RedCap UE to autonomously select and use dedicated preamble formats and RACH resources configured specifically for reduced-capability devices. The prach-ConfigurationIndex and msg1-FrequencyStart parameters provide RedCap-specific access opportunities, enabling these devices to perform random access independently without conflicting with standard UE procedures, thereby reducing access latency while maintaining protocol compatibility through the unified RACH framework.
Data Source
AI summary
A method and apparatus for accessing a NR cell in a mobile communication system are provided. Method for accessing a NR cell includes receiving, by a terminal from a base station, a System Information Block1, determining, by the terminal, a preamble format and a subframe and a starting symbol based on the prach-ConfigurationIndex included in the first RACH-ConfigCommon if the second RACH-ConfigCommon is not included in the ServingCellConfigCommon and the prach-ConfigurationIndex included in the second RACH-ConfigCommon if the second RACH-ConfigCommon is included in the ServingCellConfigCommon and transmitting, by the terminal, the preamble based at least in part on the preamble format and the subframe and the starting symbol.