NB-IoT Random Access Preamble Format Segmentation
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Solution Overview
Problem
Current wireless communication systems, particularly those supporting NarrowBand-Internet of Things (NB-IoT), face challenges in efficiently transmitting and receiving random access preambles, including distinguishing between existing and enhanced preambles, configuring subcarrier indices, and managing resource allocation for high-speed data traffic and increased device connections.
Innovation Solution
A method for transmitting and receiving random access preambles in NB-IoT systems that allows for differentiation between existing and enhanced preambles, efficient configuration of subcarrier indices, and optimized resource allocation through specific DCI field configuration and subcarrier index allocation rules, enabling efficient coexistence and operation of both preamble formats.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If only existing NPRACH preamble format is supported, then system compatibility is maintained, but the system cannot support high-speed data traffic and increased device connections
Solution Approach 1:
The patent segments the random access preamble into two distinct formats: existing NPRACH preamble format and enhanced PRACH preamble format. Each format serves specific purposes - the existing format maintains backward compatibility while the enhanced format supports high-speed data traffic and increased device connections. This segmentation allows the system to support diverse requirements without requiring all devices to handle all formats.
Solution Approach 2:
The patent introduces dynamic selection between different preamble formats based on system conditions and device capabilities. The base station can configure which preamble format to use through DCI fields, allowing the system to adapt dynamically between legacy and enhanced modes depending on traffic requirements, device capabilities, and network conditions.
2Quantity of substance
If enhanced PRACH preamble is added to support more devices, then device connection capacity increases, but difficulty in distinguishing between existing and enhanced preambles increases
Solution Approach 1:
The patent uses distinct DCI field configurations to 'color-code' or differentiate between existing NPRACH and enhanced PRACH preambles. Specific DCI fields are configured to indicate which preamble format is being used, making it easy for the base station and UE to distinguish between the two formats without confusion. This differentiation mechanism allows simultaneous support for both formats with clear identification.
3Productivity
If separate resource allocation is provided for existing and enhanced preambles, then resource management efficiency improves, but DCI configuration complexity increases
Solution Approach 1:
The patent designs the DCI configuration to be universal and multi-functional. The same DCI fields are used to configure both existing NPRACH and enhanced PRACH preambles, with the field interpretation depending on the configured preamble format. This universal configuration approach allows efficient resource allocation for both formats while avoiding the need for completely separate configuration mechanisms, thereby limiting the increase in complexity.
Data Source
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AI summary
This specification provides a method for transmitting a random access preamble by a user equipment (UE) in a wireless communication system supporting a narrow band-Internet of things (NB-IoT). Specifically, the UE receives a downlink control channel (Physical Downlink Control Channel (PDCCH)) including downlink control information (DCI) from an eNB and the DCI includes an indicator indicating whether a preamble format of a random access preamble allocated to the UE is format 0/1 or format 2. Then, the UE transmits the random access preamble to the eNB in a subcarrier allocated to the UE according to the preamble format and receives a random access response from the eNB in response to the random access preamble.