Random Access Occasion Interference Management in Full-Duplex Wireless Systems
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Solution Overview
Problem
Conventional wireless communication systems face inefficiencies in resource usage and channel access opportunities due to the prohibition of scheduling downlink transmissions during random access occasions, especially when a base station operates in full-duplex mode, limiting the ability of advanced user equipment (UE) to select between full-duplex and half-duplex random access channel occasions based on cross-link interference estimation.
Innovation Solution
The advanced UE can select between full-duplex and half-duplex random access channel occasions by determining which ones are unavailable due to the base station's full-duplex operation, allowing it to transmit a random access message during available occasions that have lower interference levels, thereby optimizing channel access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the base station operates in full-duplex mode during random access occasions, then downlink transmission efficiency is improved, but cross-link interference increases and channel access reliability deteriorates
Solution Approach 1:
The system dynamically switches the base station between full-duplex and half-duplex modes based on the random access occasion type. For conventional RACH occasions, the base station operates in half-duplex mode to avoid interference. For advanced UE RACH occasions, the base station can operate in full-duplex mode to improve efficiency, with the mode selection being adaptive and context-dependent rather than fixed.
Solution Approach 2:
Different random access occasions are treated differently based on their specific characteristics and the capabilities of accessing UEs. The system identifies whether an occasion is for conventional UE or advanced UE, and applies appropriate full-duplex or half-duplex operation accordingly, allowing localized optimization of transmission mode for different parts of the random access process.
2Productivity
If full-duplex mode is used during all random access occasions, then spectral efficiency is improved, but interference to conventional UEs increases
Solution Approach 1:
The random access channel occasions are segmented into different types: conventional RACH occasions for legacy UEs and advanced RACH occasions for full-duplex capable UEs. The base station applies different transmission modes to different segments - half-duplex for conventional occasions to avoid interference, and full-duplex for advanced occasions to maximize spectral efficiency.
Solution Approach 2:
The network acts as an intermediary that mediates between the advanced UE's desire for full-duplex operation and the conventional UE's need for interference-free access. By selectively enabling full-duplex mode only for advanced UEs during appropriate occasions, the system protects conventional UEs from interference while still allowing advanced UEs to benefit from full-duplex gains.
3Object-affected harmful factors
If the UE must wait for half-duplex occasions only, then interference is avoided, but channel access time is increased
Solution Approach 1:
The UE dynamically selects between available half-duplex and full-duplex random access occasions based on real-time channel conditions and network configuration. When full-duplex occasions are available and conditions permit, the UE can utilize them for faster channel access. When interference risks are detected, the UE switches to half-duplex occasions, creating a dynamic adaptation that minimizes both time loss and interference exposure.
Data Source
AI summary
Methods, systems, and devices for wireless communication are described. A user equipment (UE) may receive an indication of a plurality of random access occasions for uplink message transmission to a base station. The UE may determine that a first portion of the plurality of random access occasions is unavailable for use by the UE as a result of the base station operating in a full duplex mode. The UE may select one or more random access occasions from a second portion of the plurality of random access occasions instead of from the first portion based at least in part on the determining. The UE may transmit a random access message to the base station during the one or more random access occasions from the second portion.