Terminal Random Access Preamble Group Selection for 5G Resource Allocation
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Solution Overview
Problem
In the 2-step random access procedure of 5G NR, the base station lacks information on the uplink data size, leading to inefficient radio resource allocation, as the data size cannot be reported in advance, potentially resulting in excessive or insufficient resource allocation.
Innovation Solution
The terminal apparatus selects a random access preamble group based on specific conditions, including data buffer volume and path loss, to notify the base station of its status, allowing for efficient radio resource allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the 2-step random access procedure is used to reduce access steps, then the random access procedure is simplified and faster, but the base station cannot obtain uplink data size information in advance, leading to inefficient radio resource allocation
Solution Approach 1:
The terminal apparatus performs preliminary action by selecting an appropriate random access preamble group based on the uplink data size before transmitting the random access preamble. The base station detects which preamble group is used and thereby obtains the uplink data size information in advance, before allocating radio resources for the uplink data transmission.
Solution Approach 2:
The random access preamble group serves as an intermediary that carries information about the uplink data size. Instead of directly transmitting data size information, the system uses the selection of preamble groups (different groups corresponding to different data size ranges) as an indirect means to convey this information to the base station.
2Device complexity
If random resource allocation is performed without data size information, then the allocation process is simpler, but the radio resource utilization efficiency degrades due to excessive or insufficient allocation
Solution Approach 1:
The base station performs preliminary action by determining the uplink data size based on the detected random access preamble group before proceeding with radio resource allocation. This allows the base station to allocate an appropriate amount of resources in advance, avoiding both excessive and insufficient allocation.
Solution Approach 2:
The system changes the parameter used for resource allocation by using the random access preamble group index (which reflects uplink data size) as a basis for determining the allocation amount. Different preamble groups correspond to different data size ranges, and the base station adjusts resource allocation parameters accordingly.
Data Source
AI summary
A terminal apparatus executing radio communication with a base station apparatus, the terminal apparatus: transmits a first message, including a random access preamble and identification information of the terminal apparatus, for starting a random access procedure to the base station apparatus; receives a second message, including a random access response to the first message, from the base station apparatus; and selects one random access preamble group from among a plurality of random access preamble groups on the basis of a first condition, a second condition, a third condition, and a status of the terminal apparatus, in order to notify the base station apparatus of the status of the terminal apparatus when transmitting the first message. Consequently, even when a 2-step random access procedure is adopted, radio resources for the radio communication between the base station apparatus and the terminal apparatus can be used efficiently.