Random Access Preamble Reservation for On-Demand System Information
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G networks, face challenges in efficiently performing on-demand system information requests using the random access procedure (RACH), which affects bandwidth control and periodicity, and existing methods do not effectively manage these aspects.
Innovation Solution
The technology reserves specific random access preambles for upper-layer notifications within the RACH process without subsequent data transfer, allowing for on-demand system information requests by selecting and transmitting preambles and PRACH resources based on configuration parameters broadcasted by the base station, enabling efficient bandwidth management and periodicity control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional random access procedure is used for system information requests, then system information can be delivered, but bandwidth overhead increases and periodicity control is lost
Solution Approach 1:
The patent extracts the system information request function from the traditional multi-message RACH procedure and implements it through a dedicated random access preamble. This allows the request to be conveyed in a single uplink transmission without requiring subsequent data transfer messages, thereby reducing bandwidth overhead while maintaining reliable system information delivery.
Solution Approach 2:
The patent uses pre-configured random access preambles that are specifically reserved for system information requests. These preambles are prepared in advance and mapped to specific system information blocks, allowing the network to control periodicity and bandwidth usage before the actual request occurs, thus preventing overhead issues rather than addressing them reactively.
2Loss of substance
If on-demand system information requests are implemented, then bandwidth efficiency improves, but device complexity increases
Solution Approach 1:
The patent assigns different random access preambles to different system information blocks or types. This local differentiation allows user equipment to select the appropriate preamble based on which specific system information it needs, simplifying the device logic compared to generic random access while enabling precise bandwidth control at the network side.
Solution Approach 2:
The random access preamble serves multiple functions simultaneously: it initiates the random access procedure, conveys the system information request, and identifies the specific system information block needed. This multi-functionality reduces the number of separate signaling messages required, thereby reducing bandwidth overhead without significantly increasing device complexity.
3Adaptability or versatility
If random access preambles are reserved for specific requests, then request specificity improves, but preamble resource availability decreases
Solution Approach 1:
The patent reserves a partial set of random access preambles specifically for system information requests, while leaving the majority of preambles available for other purposes such as initial access and data transmission. This partial reservation provides sufficient specificity for system information requests while maintaining adequate resource availability for general random access operations.
Data Source
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AI summary
In one of its aspects the technology disclosed herein concerns a communications system comprising an access node (22) and a wireless terminal (26). The wireless terminal comprises receiver circuitry (40) and transmitter circuitry (44) as well as processor circuitry (40). The receiver circuitry (40) is configured to receive from a base station apparatus configuration parameters for a random access procedure. The configuration parameters include a set of random access preambles and physical random access channel (PRACH) resources reserved for a request of system information. The processor circuitry (40) is configured to select a random access preamble and PRACH resource from the set of random access preambles and the PRACH resources in a case of requesting the system information. The transmitter circuitry (44) is configured to transmit the random access preamble using the PRACH resource.