Slot Format Indicator and Beam Coordination for Millimeter Wave Self-Interference
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Solution Overview
Problem
In wireless communication systems, particularly in full-duplex mode, self-interference between transmit and receive chains operating in different frequency bands poses a challenge, leading to signal degradation and reduced data transmission rates due to cross-link interference.
Innovation Solution
A method where user equipment (UE) transmits capability information to a network, which determines and coordinates subcarrier spacing, beam coordination, or slot format index information to mitigate self-interference between transmit and receive chains operating in different frequency bands, allowing concurrent signal transmission and reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full-duplex communication is implemented with concurrent transmit and receive operations in different frequency bands, then data transmission rates and communication efficiency are improved, but self-interference between transmit and receive chains causes signal degradation
Solution Approach 1:
The system dynamically adjusts subcarrier spacing parameters for different frequency bands based on UE capability information. By changing the subcarrier spacing parameter (e.g., 15kHz for FR1, 120kHz for FR2), the system optimizes the frequency domain separation between transmit and receive chains, thereby mitigating self-interference while maintaining high data transmission rates in full-duplex mode
Solution Approach 2:
The system implements dynamic TDD (Time Division Duplex) schemes where the transmit and receive operations can be dynamically adjusted in time and frequency domains. The network can dynamically configure uplink-downlink slot patterns and switch between different full-duplex and half-duplex modes based on channel conditions and interference levels, allowing the system to adaptively balance between productivity and interference mitigation
2Quantity of substance
If carrier aggregation across millimeter wave bands is implemented, then communication capacity and bandwidth are increased, but coordination complexity between different frequency bands increases
Solution Approach 1:
The system employs a universal coordination mechanism where a single set of subcarrier spacing rules and slot format indicators (SFIs) can be applied across multiple aggregated frequency bands. The network can configure different component carriers with appropriate subcarrier spacing values according to their frequency ranges, providing a unified approach that simplifies the coordination complexity while enabling carrier aggregation across millimeter wave bands to increase total bandwidth
Solution Approach 2:
The system standardizes subcarrier spacing parameters across different frequency bands according to 3GPP specifications (e.g., 15kHz for FR1, 120kHz for FR2). This parameter standardization allows the network to aggregate carriers across millimeter wave bands with predictable and manageable coordination requirements, as the subcarrier spacing relationships are pre-defined and consistent throughout the system
3Adaptability or versatility
If dynamic TDD slot format switching is implemented, then flexibility in resource allocation is improved, but timing synchronization and interference coordination between UEs become more difficult
Solution Approach 1:
The system uses slot format indicators (SFIs) transmitted via downlink control information (DCI) to dynamically inform UEs of the upcoming slot formats in both FR1 and FR2 bands. This feedback mechanism allows UEs to anticipate and prepare for upcoming transmit or receive operations, maintaining timing synchronization even as slot formats switch dynamically. The network can coordinate SFIs across aggregated carriers to ensure consistent timing relationships and prevent cross-link interference
Data Source
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AI summary
Aspects of the disclosure relate to an apparatus (e.g., a user equipment (UE)) configured to operate in a full-duplex mode. The apparatus may include at least one transmit chain configured to operate within a first frequency band and at least one receive chain configured to operate within a second frequency band. The apparatus may receive coordination information that is configured to mitigate the self-interference between the at least one transmit chain and the at least one receive chain. In some examples, the received coordination information includes at least one of subcarrier spacing coordination information, beam coordination information, or slot format index coordination information. In some examples, the apparatus may transmit a first signal while receiving a second signal based on at least the subcarrier spacing coordination information, the beam coordination information, or the slot format index coordination information to mitigate self-interference.