PRACH Occasion Validation in Subband Full Duplex TDD
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Solution Overview
Problem
Existing wireless communication systems lack support for subband full duplex (SBFD) operation, particularly in configuring and validating random access channels (PRACH) in both uplink-only and SBFD symbols, leading to inefficiencies in RACH capacity and latency.
Innovation Solution
Methods and configurations are introduced to enable PRACH transmissions in both UL-only and SBFD symbols by determining RO validity based on frequency domain conditions, mapping SSB indices, and configuring preamble received target power, ensuring valid ROs are within UL subbands and utilizing separate parameters for SBFD and UL-only symbols.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If PRACH transmissions are limited to UL-only symbols, then system configuration is simple, but RACH capacity is insufficient and latency increases
Solution Approach 1:
The patent segments the frequency domain by dividing the carrier bandwidth into multiple subbands, allowing different subbands to have different transmission directions (UL-only or SBFD) simultaneously. This segmentation enables PRACH transmissions in both UL-only symbols and SBFD symbols without requiring complete system redesign, thereby increasing RACH capacity while managing complexity through modular configuration.
Solution Approach 2:
The patent applies local quality by allowing different parts of the frequency spectrum to have different properties - specific subbands can be configured as UL-only while others support SBFD operation. This enables selective PRACH transmission opportunities in different frequency regions, increasing overall RACH capacity without requiring all resources to support the more complex SBFD operation.
2Productivity
If PRACH transmissions are enabled in SBFD symbols, then RACH capacity increases, but validity determination and mapping complexity increase
Solution Approach 1:
The patent performs preliminary action by pre-configuring the subband full duplex pattern and validating random access occasions (ROs) before actual PRACH transmission. The network node determines validity of ROs in advance based on the configured pattern, and this validity information is provided to the wireless device beforehand, simplifying the detection process during transmission.
Solution Approach 2:
The patent implements feedback mechanisms where the network node provides validity information about ROs to the wireless device. This feedback enables the device to accurately determine which ROs are valid for PRACH transmission in SBFD symbols, reducing the complexity of real-time validity determination and ensuring correct transmission timing.
3Manufacturing precision
If separate parameters are configured for SBFD and UL-only symbols, then transmission accuracy is improved, but configuration complexity increases
Solution Approach 1:
The patent applies universality by designing a unified PRACH configuration framework that can handle both UL-only symbols and SBFD symbols through a single set of configuration mechanisms. The network node configures subband full duplex patterns and validates ROs using consistent procedures, and the wireless device processes both symbol types through unified validation logic, reducing the need for completely separate parameter sets while maintaining transmission accuracy.
Data Source
AI summary
A method, network node and wireless device (WD) for a physical random access channel (PRACH) for subband full duplex operation are disclosed. According to one aspect, a wireless device configured to communicate with a network node is provided. The wireless device is configured to receive frequency domain configuration information and time domain configuration information indicating a plurality of subband full duplex, SBFD, symbols and a plurality of uplink-, UL-, only symbols in a time division duplex, TDD, configuration, and determine a validity of a random access channel, RACH, occasion, RO, based on whether a validity condition is met, the RO being positioned in at least one SBFD symbol of the plurality of SBFD symbols or in at least one UL-only symbol of the plurality of UL-only symbols.