PRACH Configuration in Subband Full-Duplex Systems
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face inefficiencies in random access procedures due to limitations in the configuration of physical random access channel (PRACH) occasions and frequency domain resource allocation, which can lead to interference and reduced spectral efficiency in subband full-duplexing (SBFD) systems.
Innovation Solution
The proposed solution involves configuring PRACH occasions and frequency domain positions based on slot types, allowing for flexible and efficient use of spectrum by considering partitioned and non-partitioned slots, and employing specific frequency hopping offsets to prevent interference with downlink subbands in partitioned slots, thereby optimizing the random access procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If PRACH occasions are configured in partitioned slots without frequency domain validation, then more uplink resources are available for random access, but interference with downlink subbands occurs
Solution Approach 1:
The patent applies local quality by making PRACH occasion validity conditional on the specific frequency domain location within partitioned slots. Instead of uniformly allowing or disallowing PRACH in all partitioned slots, the system validates each PRACH occasion based on its frequency domain position relative to downlink subbands, allowing PRACH in safe frequency regions while blocking it in interference-prone regions.
Solution Approach 2:
The patent changes the validation parameter from purely time-domain (slot type) to include frequency-domain position. By introducing frequency domain validation, the system dynamically determines PRACH occasion validity based on the specific frequency resources allocated, enabling flexible adaptation to different slot configurations and preventing interference while maximizing resource utilization.
2Object-affected harmful factors
If frequency domain validation is added to PRACH occasion validity check, then interference is reduced, but procedure complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the frequency domain resource allocation information and downlink subband locations before PRACH transmission. The UE receives and stores this configuration data in advance, enabling it to perform rapid frequency domain validation during the random access procedure without complex real-time calculations or additional signaling overhead.
3Object-affected harmful factors
If PRACH occasions are restricted to non-partitioned slots only, then interference is avoided, but spectral efficiency decreases
Solution Approach 1:
The patent applies segmentation by dividing partitioned slots into different frequency domain regions - some suitable for PRACH transmission and others reserved for downlink. This segmentation allows the system to utilize only the appropriate frequency resources for uplink random access within partitioned slots, avoiding interference with downlink while maximizing the usable uplink resource pool.
4Quantity of substance
If PRACH occasions are allowed in all time units, then uplink resource availability is maximized, but time domain collision with downlink transmissions occurs
Solution Approach 1:
The patent transitions from one-dimensional time-domain validation to two-dimensional validation by incorporating frequency domain position into the PRACH occasion validity determination. This dimensional expansion allows the system to allow PRACH in partitioned slots at safe frequency positions while blocking it at positions that would cause time-frequency overlap with downlink transmissions, thereby maximizing resource utilization without causing collisions.
Data Source
AI summary
In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a UE. The UE receives a configuration of physical random access channel (PRACH) occasions from a base station. The configuration indicates one or more PRACH occasions located in each time unit of a set of time units. The UE determines whether a first PRACH occasion in a first time unit of the set of time units is valid in the time domain by assessing whether the first time unit is partitioned or non-partitioned. The UE transmits a random access preamble at the first PRACH occasion when the first PRACH occasion is valid in the time domain and is also valid in the frequency domain.