Broadcast Channel Mapping for Scalable Bandwidth Cellular Systems
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In cellular wireless communication systems with scalable bandwidth, User Equipment (UE) face difficulties in performing cell searches and receiving system information from neighboring cells without changing their reception RF frequencies, especially when their bandwidth is smaller than the system bandwidth, leading to challenges in decoding broadcast channel information.
Innovation Solution
The method involves generating primary and secondary broadcast channel symbols, mapping them to specific frequency bands within the system band, allowing UEs to receive system information from neighboring cells without frequency changes, by using primary BCH symbols for basic information and secondary BCH symbols for core information, which are transmitted through subcarriers in adaptable bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If BCH is transmitted only in the center 1.25 MHz band, then system information can be transmitted in a fixed location, but UEs with limited bandwidth cannot receive BCH from neighboring cells without frequency changes
Solution Approach 1:
The patent divides the system band into multiple 10 MHz bands and transmits BCH in both the center 1.25 MHz band and the edges of each 10 MHz band. This segmentation allows UEs with different bandwidth capabilities to receive BCH from appropriate locations - center for full-bandwidth UEs, edges for limited-bandwidth UEs - thereby resolving the contradiction between fixed transmission reliability and bandwidth adaptability.
2Loss of information
If UEs change reception RF frequency to receive BCH from neighboring cells, then system information can be acquired, but service continuity is interrupted and mobility is hindered
Solution Approach 1:
By segmenting BCH transmission locations to include both center and edge bands, the patent enables UEs to receive neighboring cell BCH information while remaining on their current frequency, eliminating the need for frequency changes during cell reselection and thus maintaining service continuity and ease of mobility operation.
Solution Approach 2:
The patent introduces BCH transmission at band edges as an intermediary mechanism that bridges the gap between current service frequency and neighboring cell information, allowing UEs to acquire system information without leaving their current frequency position.
3Quantity of substance
If BCH transmission bandwidth matches system bandwidth, then all system information can be transmitted, but UEs with smaller bandwidth cannot receive the entire BCH
Solution Approach 1:
The patent segments BCH transmission into multiple locations (center and edges of 10 MHz bands) with different bandwidth characteristics. This allows the system to transmit comprehensive system information while providing multiple access points that accommodate UEs with different bandwidth capabilities, resolving the contradiction between information quantity and bandwidth compatibility.
Data Source
AI summary
A method and apparatus for transmitting/receiving broadcast channels carrying downlink system information in an Orthogonal Frequency Division Multiplexing (OFDM)-based cellular wireless communication system supporting a scalable bandwidth. The method includes mapping first primary broadcast channel (P1-BCH) symbols including basic system information to a middle band centered at a center frequency of a system band and having a broadcast channel (BCH) transmission bandwidth, and mapping second primary broadcast channel (P2-BCH) symbols including core system information excluding the basic system information to first and second transmission bands that have the BCH transmission bandwidth and locate within both bands adjoining the center frequency on both sides thereof and having a minimum reception bandwidth supportable by User Equipments (UEs) within a cell respectively, when a bandwidth of the system band is at least two times of a minimum reception bandwidth. In this way, the method and system facilitates a UE to move between cells.