Dynamic RACH Slot Configuration for 5G Spectrum Efficiency
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Solution Overview
Problem
Current wireless communication systems, particularly in the context of 5G NewRAT, face challenges in efficiently managing random access channels due to the need for flexible communication scenarios that include enhanced mobile broadband, ultra-reliable and low-latency communications, and massive machine-type communications, which require adaptable random access channel (RACH) slot configurations to optimize spectrum efficiency and latency.
Innovation Solution
The method involves generating and transmitting acknowledgement information per contention-based grant (CBG) included in data received in one or more slots, allowing for dynamic adjustment of RACH slot lengths based on PRACH configuration, enabling efficient resource allocation and minimizing latency in multi-beam environments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed-length RACH slots are used, then device complexity is reduced, but spectrum efficiency and latency performance deteriorate
Solution Approach 1:
The patent implements dynamic RACH slot length adjustment based on PRACH configuration index, where different RACH slot lengths (e.g., 1ms, 0.5ms, 0.25ms) are selected according to the configured index value. This allows the system to adapt RACH slot duration to different service requirements, improving spectrum efficiency while maintaining manageable device complexity through standardized dynamic adjustment rules.
2Ease of operation
If fixed-length RACH slots are used, then system operation is simplified, but latency performance worsens
Solution Approach 1:
The patent enables dynamic selection of RACH slot lengths based on PRACH configuration index, allowing shorter RACH slots (e.g., 0.25ms) to be used when low latency is required. This dynamic adjustment maintains operational simplicity through standardized procedures while significantly reducing access latency compared to fixed-length slots.
3Productivity
If variable-length RACH slots are implemented, then spectrum efficiency is improved, but device complexity increases
Solution Approach 1:
The patent changes the RACH slot length parameter based on PRACH configuration index values. The network configures different index values that correspond to different slot lengths, and the UE adjusts its RACH transmission accordingly. This parameter-based approach improves spectrum efficiency while keeping device complexity manageable through standardized parameter mappings.
4Loss of time
If variable-length RACH slots are implemented, then access latency is reduced, but device complexity increases
Solution Approach 1:
The patent implements dynamic RACH slot length selection where the UE determines the appropriate slot length based on the PRACH configuration index received from the network. This allows latency reduction through shorter slots while maintaining manageable device complexity through standardized dynamic adjustment procedures.
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AI summary
The present invention provides a method for transmitting a random access channel (RACH). Particularly, the method includes receiving PRACH configuration information including information about a slot (RACH slot) available for transmission of the RACH and information indicating a subcarrier spacing for a PRACH, and transmitting a RACH preamble in the RACH slot on the basis of the PRACH configuration information and the subcarrier spacing, wherein the length of the RACH slot depends on the subcarrier spacing.