Fallback System Information Blocks for Low-Latency Network Access
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Solution Overview
Problem
Existing wireless communication systems face latency issues due to the need for decoding downlink control information (DCI) during the initial connection process, which consumes additional processing resources and time, especially when DCI decoding fails.
Innovation Solution
Implementing a fallback system information block (SIB) that is transmitted and received without the use of DCI, with predefined frequency and time domain resource assignments, modulation and coding schemes, and demodulation reference signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If DCI is used to transmit system information blocks, then network control and scheduling flexibility is improved, but latency increases due to additional decoding steps
Solution Approach 1:
The system information blocks are segmented into two types: fallback SIBs transmitted without DCI for rapid access, and non-fallback SIBs transmitted with DCI for enhanced control. This segmentation allows UEs to receive critical system information immediately while maintaining the option for scheduled transmissions of additional information.
Solution Approach 2:
Fallback system information blocks are transmitted in advance without requiring DCI decoding, preparing UEs with essential network access information before they need to establish connections. This preliminary action eliminates the need for real-time DCI decoding during initial access, reducing latency.
2Manufacturing precision
If DCI decoding is performed during initial connection, then scheduling accuracy is improved, but processing complexity and time consumption increase
Solution Approach 1:
Different quality levels of scheduling are applied to different system information blocks. Fallback SIBs use simplified transmission without DCI for basic access needs, while non-fallback SIBs use DCI-based scheduling for enhanced precision when needed. This local differentiation optimizes the balance between complexity and accuracy.
Solution Approach 2:
The system applies partial DCI decoding action only when necessary for non-fallback SIBs, rather than requiring full DCI processing for all system information. This partial action reduces processing complexity while maintaining scheduling accuracy where it matters most.
3Loss of time
If fallback SIB is transmitted without DCI, then latency is reduced, but network control flexibility is decreased
Solution Approach 1:
The system uses a universal indicator bit within the SSB that can signal both the availability of fallback SIBs and provide basic scheduling information. This multi-functional approach allows rapid access through fallback SIBs while preserving network control flexibility through the same signaling mechanism.
Solution Approach 2:
The SSB indicator bit acts as an intermediary that bridges the gap between DCI-free fallback SIB transmission and DCI-based scheduled transmissions. It provides a lightweight signaling mechanism that enables fast access while maintaining the option for flexible network control through subsequent DCI messages.
Data Source
AI summary
Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may receive a signal synchronization block (SSB) associated with a network cell, where the SSB includes at least one bit indicating that the network cell provides a fallback system information block (SIB). The UE may receive the fallback SIB, where the fallback SIB is received without using downlink control information. Numerous other aspects are described.