Random Access Preamble Selection by Msg3 Size in 5G NR
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Solution Overview
Problem
Current random access procedures in wireless communication systems, such as LTE, are not suitable for 5G or New Radio (NR) systems, as they lack the granularity to efficiently convey small packet sizes during the random access process, leading to inefficiencies in resource allocation.
Innovation Solution
The proposed solution involves configuring candidate subframe and system frame numbers for random access preambles based on the size of Msg3, allowing for finer granularity in indicating the size of messages transmitted during the random access procedure, using subframe numbers, system frame numbers, or combinations thereof to determine PRACH transmission groups and allocate resources accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If current random access procedures are used in LTE systems, then the random access process can be completed, but the granularity is insufficient to efficiently convey small packet sizes during random access, leading to resource allocation inefficiencies
Solution Approach 1:
The patent segments the random access procedure by dividing Msg3 transmissions into different groups based on message size thresholds. Terminal devices select specific PRACH resources (subframe numbers, system frame numbers) that correspond to different Msg3 size ranges, enabling the network to efficiently allocate resources based on the actual message size without wasting bandwidth on oversized allocations.
Solution Approach 2:
The patent changes the parameter of PRACH resource selection by introducing size-dependent thresholds and mapping relationships. Instead of using a uniform random access procedure, the system now uses different subframe numbers, system frame numbers, or preamble groups based on the Msg3 size, allowing the network to optimize resource allocation parameters according to the actual data transmission needs.
2Productivity
If finer granularity is introduced to indicate message sizes during random access, then resource allocation efficiency improves, but the complexity of the random access procedure increases
Solution Approach 1:
The patent applies preliminary action by having terminal devices determine the appropriate PRACH resource group before transmitting the random access preamble. The device calculates the Msg3 size, compares it against configured thresholds, and selects the corresponding resource group in advance. This preliminary classification simplifies the overall procedure by avoiding complex real-time decisions during the random access process itself.
Solution Approach 2:
The patent adds another dimension to the random access procedure by introducing size-based resource grouping alongside the traditional time-frequency-preamble dimensions. Instead of merely selecting from available PRACH resources, devices now select from multiple dimensions including message size category, which maps to specific subframe numbers, system frame numbers, or preamble groups, creating a multi-dimensional resource selection framework.
Data Source
AI summary
Embodiments of the present disclosure provide methods, apparatuses and computer program products for random access in a wireless communication system. A method in a terminal device comprises receiving a random access configuration from a network device, the random access configuration including information for determining a set of candidate subframe numbers and a set of candidate system frame numbers for transmitting a random access preamble; transmitting the random access preamble in a subframe within a radio frame, the subframe being associated with a subframe number, and the radio frame being associated with a system frame number; wherein the subframe number is selected from the set of candidate subframe numbers, and/or, the system frame number is selected from the set of candidate system frame numbers t, based on a size of a Message 3 (Msg3) to be transmitted by the terminal device to the network device during the random access.