RACH Resource Switching to Limit Subband Full-Duplex Interference
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Solution Overview
Problem
In subband full-duplex communication, UEs face challenges with continuous PRACH transmission failures due to interference between downlink and uplink subbands, leading to radio link failures and degraded system performance, particularly for SBFD-aware UEs.
Innovation Solution
A method and apparatus for a terminal to determine a second RACH resource type on non-SBFD symbols when the maximum number of preamble transmissions on SBFD symbols is exceeded, restricting further attempts to non-SBFD symbols to mitigate interference and prevent radio link failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If UEs continuously transmit preambles on SBFD symbols, then the system attempts to maintain resource utilization, but PRACH transmission failures increase due to interference between downlink and uplink subbands
Solution Approach 1:
The patent implements dynamic switching between SBFD and non-SBFD RACH resources based on transmission failure conditions. When the number of preamble transmissions exceeds a threshold, the UE dynamically switches from SBFD symbols to non-SBFD symbols for subsequent transmissions, allowing the system to adapt resource selection based on real-time transmission outcomes and interference conditions
Solution Approach 2:
The patent changes the parameter of RACH resource type from fixed to variable based on transmission attempts. The system transitions from using only SBFD RACH resources to conditionally using non-SBFD RACH resources when transmission failures occur, effectively changing the resource selection parameter in response to interference conditions
2Productivity
If UEs use SBFD symbols for RACH transmission, then spectrum efficiency is improved through full-duplex operation, but interference between downlink and uplink subbands degrades communication reliability
Solution Approach 1:
The patent introduces non-SBFD symbols as an intermediary resource type that UEs can switch to when SBFD resources become unusable due to interference. This intermediary resource provides a fallback mechanism that mediates between the desire for full-duplex efficiency and the need to avoid interference-induced failures
3Loss of energy
If the maximum number of preamble transmissions is exceeded on SBFD symbols, then the system prevents excessive resource consumption, but radio link failures occur due to persistent interference
Solution Approach 1:
The patent implements preliminary action by pre-configuring both SBFD and non-SBFD RACH resources and establishing a switching mechanism before transmission failures become critical. When the transmission threshold is exceeded, the system has already prepared alternative resources, preventing radio link failures before they occur rather than reacting after damage is done
Data Source
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AI summary
Provided are a method and apparatus for determining a random access channel (RACH) resource type in subband full duplex (SBFD) of a wireless communication system. The method of the terminal may include receiving information on a maximum number of preamble transmissions through a subband full duplex (SBFD) symbol, transmitting at least one first preamble through a first random access channel (RACH) resource, and determining a second RACH resource configured on a non-SBFD symbol when a number of transmissions of the at least one first preamble exceeds the maximum number of preamble transmissions through the SBFD symbol.