SBFD Random Access Mapping for Cross-Link Interference Mitigation
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies and failures in subband full duplex (SBFD) random access procedures due to inconsistent mapping of synchronization signal blocks (SSBs) to random access occasions (ROs), particularly for SBFD-aware UEs, leading to potential cross-link interference and reduced efficiency.
Innovation Solution
A method and apparatus for SBFD-aware UEs to perform separate SSB-RO mappings for uplink and SBFD symbols, using ascending/descending order or prioritized beam directions, and adjust transmit power and preamble formats to mitigate cross-link interference, enabling efficient SBFD operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate SSB-RO mappings are performed for uplink and SBFD symbols, then mapping consistency and reliability are improved, but device complexity and processing overhead increase
Solution Approach 1:
The patent divides the SSB-RO mapping process into separate mappings for uplink symbols and SBFD symbols. The UE performs a first mapping for uplink ROs and a second mapping for SBFD ROs, with each mapping having its own rules and parameters. This segmentation resolves the contradiction by ensuring mapping consistency through dedicated procedures while managing complexity through structured separation.
Solution Approach 2:
The patent implements dynamic mapping selection where the UE can adaptively choose between different mapping approaches based on the specific scenario. The network can configure different mapping types (e.g., type 1 and type 2) and the UE dynamically applies the appropriate mapping rules for uplink or SBFD symbols, providing flexibility that balances reliability with processing efficiency.
2Reliability
If transmit power is adjusted to mitigate cross-link interference, then interference reduction and reliability are improved, but power consumption and loss increase
Solution Approach 1:
The patent changes the transmit power parameter dynamically based on the duplex mode and interference conditions. For SBFD symbols, the UE adjusts the transmit power of random access messages according to network configuration and measured interference levels. This parameter adjustment mitigates cross-link interference while optimizing power consumption by applying power control only when and where necessary.
Solution Approach 2:
The patent applies preliminary power adjustment before transmission to prevent cross-link interference from occurring in the first place. The network configures appropriate power levels and the UE pre-calculates the required transmit power based on path loss and interference measurements, thereby preventing interference issues rather than correcting them after they occur, which reduces overall power waste.
3Adaptability or versatility
If multiple control signaling messages are used for configuring RO sets and mappings, then configuration flexibility and adaptability are improved, but signaling overhead and complexity increase
Solution Approach 1:
The patent designs control signaling messages that serve multiple functions simultaneously. The same downlink control information (DCI) or RRC message structure is used to configure both uplink ROs and SBFD ROs, as well as to indicate mapping parameters and power control settings. This multi-functionality reduces the number of separate signaling messages needed while maintaining full configuration flexibility for different scenarios.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A user equipment (UE) may perform a first synchronization signal block (SSB) to random access occasion (RO) mapping for ROs located in uplink symbols according to a first rule, and may perform a second SSB to RO mapping for ROs located in subband full duplex (SBFD) symbols according to a second rule. A UE that is experiencing cross-link interference (CLI) due to SBFD operations by another UE may transmit an indication of the sensed CLI due to the SBFD operations to the network entity. In such examples, the network entity may disable SBFD ROs, or may stop full duplex (FD) operations at an aggressor UE. The network entity may configure a transmit power, target receive power, or ramping step size for SBFD ROs to mitigate CLI. The network entity may configure different preamble formats for SBFD ROs than for other ROs.