Downlink Initial Access Channel Bandwidth Segmentation
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Solution Overview
Problem
Existing wireless communication systems face inefficiencies in initial access due to the requirement for UE to match its reception bandwidth with the system transmission bandwidth, leading to longer access times and increased complexity.
Innovation Solution
A downlink initial access channel is designed with a bandwidth less than the system bandwidth, incorporating a basic and Extended Synchronization Channel (SCH) and Broadcast-Control Channel (BCH) structure, allowing for flexible UE capabilities and reduced blind bandwidth search time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the IACH bandwidth is equal to the system transmission bandwidth, then the system supports full bandwidth transmission, but the UE access time increases and complexity increases due to blind bandwidth search
Solution Approach 1:
The patent segments the access channel into two distinct channels: a basic synchronization channel (SYNC-Ch) with fixed narrow bandwidth for initial access, and an extended synchronization channel (EXT_SYNC_Ch) for bandwidth information transmission. This segmentation allows UEs to first access using a simple narrow channel without bandwidth uncertainty, then obtain bandwidth information to configure their reception for full system bandwidth, thereby resolving the contradiction between access speed and search complexity.
Solution Approach 2:
The patent implements preliminary action by transmitting bandwidth configuration information through the extended synchronization channel before the UE needs to access the full bandwidth system. The UE first synchronizes using the basic channel, then receives bandwidth information in advance, allowing it to configure its reception parameters before attempting full bandwidth access. This eliminates the need for blind bandwidth searching and reduces access time.
2Adaptability or versatility
If the IACH bandwidth equals system bandwidth, then full system capacity is utilized, but UE reception capability requirements increase
Solution Approach 1:
The patent applies dynamics by making the access channel bandwidth adaptive rather than fixed. The system provides a basic synchronization channel with fixed narrow bandwidth that all UEs can receive, and an extended channel that provides bandwidth information dynamically. This allows the system to adapt to different UE reception capabilities - UEs with limited capability use only the basic channel, while UEs with higher capability can access the full system bandwidth after receiving configuration information.
3Productivity
If the access channel uses full system bandwidth, then spectrum efficiency is maximized, but access time increases due to synchronization requirements
Solution Approach 1:
The patent segments the access process into two phases: initial synchronization using a narrow basic channel that achieves quick time/frequency synchronization, and subsequent full bandwidth access using the extended channel. This segmentation allows the system to achieve fast initial access with minimal time loss, then utilize full system bandwidth for data transmission, thereby maintaining spectrum efficiency while reducing access time.
Data Source
AI summary
Physical layer structures and access schemes for use in such networks are described and in particular initial access channel (IACH) structures are proposed. A spectrum efficient downlink (DL) IACH design supports different types of User Equipment (UE) capabilities and different system bandwidths. An IACH includes the synchronization channel (SCH) and broadcast-control channel (BCH). A non-uniform SCH for all system bandwidths is provided, as well as scalable bandwidth BCH depending on system bandwidth. An initial access procedure is provided, as well as an access procedure.