On-Demand SSB Configuration via RACH Occasion Mapping
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Solution Overview
Problem
Current wireless communication systems lack rules and signaling to determine whether a network entity should monitor for and allow user equipment (UE) to transmit in random access channel (RACH) occasions corresponding to on-demand synchronization signal blocks (SSBs) that were not transmitted.
Innovation Solution
The implementation of rules and signaling to indicate whether a network entity should monitor for and allow a UE to transmit in RACH occasions corresponding to on-demand SSBs, enabling on-demand transmission of SSBs and dynamic indication of corresponding RACH occasions via downlink control information (DCI).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If on-demand SSB transmission is implemented to save network energy, then energy consumption is reduced, but the network lacks clear rules and signaling for determining whether to monitor RACH occasions corresponding to transmitted SSBs
Solution Approach 1:
The patent segments the SSB transmission modes into two distinct types: periodic SSB transmission and on-demand SSB transmission. This segmentation allows the network to apply different monitoring rules for RACH occasions based on which mode is used, thereby reducing unnecessary monitoring and energy consumption while maintaining clear operational guidelines through the segmentation itself.
Solution Approach 2:
The patent introduces feedback mechanisms where the network entity monitors whether an on-demand SSB was successfully transmitted before determining whether to monitor the corresponding RACH occasion. This feedback loop enables energy-efficient operation by avoiding unnecessary monitoring when SSB transmission fails or is not performed, while the feedback itself is managed through standardized signaling procedures.
2Ease of operation
If separate mappings are provided between on-demand SSBs and ROs and legacy SSBs and ROs, then transmission rules are clarified, but device complexity increases
Solution Approach 1:
The patent makes the mapping between SSBs and RACH occasions universal by allowing the same mapping structure to serve both periodic and on-demand SSB transmission modes. The network entity and UE use a unified approach to handle both types of SSBs, reducing the need for separate complex mapping configurations while maintaining clear operational rules through the universal framework.
3Speed
If dynamic indication of RACH occasion is provided via DCI in response to SSB request, then low-latency communication is enabled, but network processing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-configuring the mapping between SSBs and RACH occasions through system information or RRC signaling before actual communication occurs. This pre-configuration allows the network to quickly respond to SSB requests by simply indicating the pre-established mapping relationship through DCI, achieving low latency without requiring complex real-time processing or dynamic mapping calculations.
Data Source
AI summary
Methods, systems, and devices for wireless communications are described. To save energy at the network, synchronization signal blocks (SSBs) may be transmitted in an on-demand manner. For example, the network may transmit an SSB in response to a request for an SSB or an uplink wake-up signal (WUS) from a user equipment (UE). SSBs may be mapped to corresponding random access channel occasions (ROs) via control signaling such as radio resource control or system information. For example, the described techniques provide for rules and/or signaling that may indicate whether a network entity should monitor for, and thus whether a UE may transmit, in ROs corresponding to on-demand SSBs. In some examples, a UE may transmit a request for an on-demand SSB, receive an SSB based on the request, and selectively transmit a message to the network entity in an RO corresponding to the SSB based on reception of the SSB.