Multiple SSB Beam Transmission With SSB-Specific RACH Resources
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Solution Overview
Problem
Conventional RACH configurations in wireless communication systems are inadequate for multi-cell environments where multiple base stations or TRPs transmit orthogonal SSBs, leading to scalability issues and difficulties in determining the correct RACH occasion and preamble for UEs with multiple RF capabilities.
Innovation Solution
The solution involves allowing UEs to receive multiple SSBs simultaneously over different transmission beams and associating different RACH occasions or designated subsets of preambles with these SSBs, enabling improved beam detection and uplink reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple base stations transmit orthogonal SSBs in multi-cell environments, then beam detection capability is improved, but scalability and UE capability requirements worsen
Solution Approach 1:
The patent segments the RACH preambles into different sets (first set and second set) that are respectively associated with first and second cells. This segmentation allows UEs to identify which cell's SSB they received and select the appropriate RACH occasion and preamble accordingly, enabling multi-cell operation without requiring UE capabilities to handle all possible combinations, thus improving scalability.
Solution Approach 2:
The patent introduces SSB-specific RACH occasions and preamble sets as intermediaries between the SSB transmission and the RACH procedure. These intermediaries provide a clear mapping relationship that helps UEs determine the correct RACH resources based on the received SSB, simplifying the UE's decision-making process and reducing the burden on UE capabilities while maintaining multi-cell scalability.
2Device complexity
If conventional RACH configurations are used, then device complexity is reduced, but ease of operation deteriorates due to difficulty in determining correct RACH occasion and preamble
Solution Approach 1:
The patent establishes a feedback mechanism where the SSB transmission provides implicit feedback information about which RACH occasion and preamble set should be used. The UE uses this feedback (the association between SSB and RACH resources) to automatically select the correct RACH parameters, making the operation easier without requiring complex configuration or manual selection by the UE.
Solution Approach 2:
The patent performs preliminary action by pre-configuring the association between different cells/SSBs and their respective RACH occasions and preamble sets. This preliminary setup is done by the network side, and the UE simply needs to follow the pre-established mapping, significantly simplifying UE operation while keeping the configuration manageable.
3Reliability
If multiple SSBs are transmitted simultaneously over different beams, then uplink reception is improved, but device complexity increases due to differentiated RACH preambles requirements
Solution Approach 1:
The patent segments the RACH preambles into different sets that correspond to different cells or TRPs. This segmentation allows the system to maintain differentiated RACH configurations for simultaneous SSB transmissions without requiring the UE to handle all possible combinations, thus improving uplink reception reliability while managing device complexity through structured organization of the configuration.
Data Source
AI summary
Aspects of the present disclosure allow a base station to simultaneously send SSBs to a UE and to associate different ROs or designated subsets of preambles with the simultaneously transmitted SSBs. The base station may configure a time or frequency offset for different ROs, or a number of preamble cyclic shifts associated with the SSBs. The base station then simultaneously sends a plurality of SSBs to the UE, where each of the SSBs is associated with a different beam, and where each of the SSBs is associated with a different RO or a designated subset of preambles. After the UE simultaneously obtains the SSBs from the base station, the UE may determine the offset for one of the different ROs, or the number of preamble cyclic shifts associated with one of the SSBs. The UE may then send a preamble to the base station in response to the determination.