Virtual RACH Occasions for OCB Compliance
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently managing random access channel (RACH) occasions, particularly in bands with occupied channel bandwidth (OCB) requirements, where longer RACH preambles are needed to satisfy OCB thresholds, but this can lead to impractical frequency division multiplexing due to increased message size, affecting spectral efficiency and capacity.
Innovation Solution
The implementation of multiple RACH occasions associated with the same time-frequency resource allocation, referred to as virtual RACH occasions, allows for the use of longer RACH sequences that satisfy OCB requirements without compromising random access capacity, by assigning different preamble sequence sets to each occasion, enabling efficient frequency division multiplexing and increased capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If longer RACH preambles are used to satisfy OCB thresholds, then OCB requirements are met, but frequency division multiplexing becomes impractical due to increased message size
Solution Approach 1:
The patent segments the RACH preamble transmission by introducing multiple virtual RACH occasions that share the same time-frequency resources. Each virtual RACH occasion is assigned a unique preamble sequence set, allowing the system to differentiate between multiple RACH transmissions without requiring frequency division multiplexing. This segmentation approach maintains OCB compliance while avoiding the complexity of frequency division multiplexing with longer preambles.
Solution Approach 2:
The patent transitions from frequency-domain multiplexing to sequence-domain multiplexing by assigning different preamble sequences to different virtual RACH occasions. This dimensional change allows the system to satisfy OCB requirements with longer preambles while maintaining practical multiplexing capabilities through sequence differentiation rather than frequency separation.
2Productivity
If multiple RACH occasions are introduced with different preamble sequence sets, then random access capacity is increased, but configuration complexity increases
Solution Approach 1:
The patent changes the sequence parameter by deriving multiple preamble sequence sets from a single base sequence set through cyclic shifts and other transformations. This parameter-based approach allows the system to create multiple distinct preamble sequences without requiring separate configurations for each sequence set, thereby increasing random access capacity while keeping configuration complexity manageable.
Solution Approach 2:
The patent implements self-service by enabling the UE to autonomously select appropriate virtual RACH occasions and corresponding preamble sequences based on pre-configured rules and parameters. The UE can independently determine which virtual RACH occasion to use and which preamble sequence to transmit without requiring complex real-time coordination with the base station, thereby increasing access capacity while simplifying overall system configuration.
Data Source
AI summary
This disclosure provides systems, methods, and apparatuses for random access channel (RACH) occasions that overlap each other in time and frequency. In one aspect, the RACH occasions may use different preamble sequence sets. A base station may signal configuration information indicating the preamble sequence sets for the RACH occasions and information indicating a time-frequency resource allocation of the RACH occasions. A UE may perform a random access procedure in accordance with the configuration information.