Dynamic Mixed Mode Beam Correspondence in mmWave
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Solution Overview
Problem
Wireless communications systems operating in millimeter wave (mmW) frequencies face challenges with signal attenuation and path losses, requiring efficient beamforming techniques, but existing methods often result in doubled beam training overhead due to separate training for uplink and downlink beams, and lack of dynamic signaling for partial beam correspondence capabilities.
Innovation Solution
A method and apparatus for dynamic mixed mode beam correspondence, where a device transmits a capability indicating the status of beam correspondence based on different antenna elements for downlink and uplink communications, allowing for time-dependent and TCI-state-dependent beam correspondence, enabling power savings and thermal reductions, and allowing the base station to determine operating modes for the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate beam training is performed for uplink and downlink beams in mmW communications, then beamforming performance is improved, but signaling overhead is doubled
Solution Approach 1:
The patent combines uplink and downlink beam training procedures by leveraging beam correspondence, where the downlink beam training results are reused for uplink beamforming. This merging approach maintains reliable beamforming performance while eliminating redundant signaling overhead associated with separate training procedures.
Solution Approach 2:
The patent implements a universal beam training framework where a single set of beam training operations serves multiple purposes - both downlink beamforming and uplink beamforming. By establishing beam correspondence, the same training results are applied universally across both communication directions, reducing overall signaling requirements.
2Device complexity
If different antenna elements are used for downlink and uplink communications, then device complexity is reduced, but beam correspondence capability is degraded
Solution Approach 1:
The patent introduces dynamic beam correspondence indication that adapts to the actual antenna configuration. When different antenna elements are used for downlink and uplink, the system dynamically indicates partial beam correspondence capability, allowing flexible operation without requiring fixed antenna configurations. This dynamic approach maintains adaptability while supporting simplified device designs.
Solution Approach 2:
The patent changes the beam correspondence parameter from a binary state (full correspondence) to a dynamic state that reflects the actual antenna element usage. By introducing time-dependent and TCI-state-dependent beam correspondence indicators, the system adapts parameters to match the physical antenna configuration, enabling reduced device complexity without complete loss of beam correspondence capability.
3Loss of information
If static beam correspondence indication is used, then signaling overhead is reduced, but adaptability to changing communication conditions is lost
Solution Approach 1:
The patent implements periodic beam correspondence indication updates triggered by specific events such as TCI state changes, antenna configuration changes, or communication condition variations. This periodic action maintains low signaling overhead during stable conditions while automatically adapting when changes occur, balancing overhead reduction with necessary adaptability.
Solution Approach 2:
The patent introduces feedback mechanisms where the receiving device reports beam correspondence status and capability information to the transmitting device. This feedback loop enables adaptive beam management by providing real-time information about actual beam correspondence conditions, allowing the system to adjust beamforming strategies dynamically without excessive signaling overhead.
4Reliability
If full beam correspondence is maintained for all TCI states, then communication reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies partial beam correspondence to only those TCI states where it is actually needed and beneficial. Instead of maintaining full beam correspondence for all TCI states, the system selectively applies beam correspondence indications to specific TCI states based on communication conditions, antenna configuration, and service requirements. This partial action approach maintains necessary communication reliability while reducing power consumption associated with maintaining beam correspondence across all states.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. A first device may indicate a dynamic beam correspondence operation for communications with a second device. For example, the dynamic beam correspondence operation may be declared in a time-dependent manner, for certain transmission configuration indication (TCI) states or time-dependent TCI states. Further, the first device may declare no beam correspondence and associated power savings and thermal reductions that result from the lack of beam correspondence. Subsequently, based on the dynamic beam correspondence operation, the second device may identify parameters (e.g., which TCI states, subarrays) for the first device to use for different modes or procedures (e.g., at a corresponding time) based on parameters that correspond to a full beam correspondence or no beam correspondence. For example, the parameters may be used for initial access, beam failure recovery, low power modes, or high temperature modes.