Base Station Signal Mapping for LTE-LTE+ Coexistence
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Solution Overview
Problem
In an integrated communication system where both LTE and LTE+ systems coexist, there is a need for an efficient method to map synchronization and broadcast signals across multiple unit bands, ensuring compatibility and resource utilization for terminals with varying bandwidth capabilities.
Innovation Solution
A base station configuration that multiplexes synchronization and broadcast signals, allowing LTE terminals to interpret signals in part of the unit bands while LTE+ terminals can interpret additional dynamic signals across all bands, with a band assignment method that enables terminals to shift reception bands for optimal data communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If synchronization and broadcast channels are mapped in every unit band, then LTE terminals can find synchronization in any unit band, but resource usage efficiency deteriorates
Solution Approach 1:
The communication band is divided into multiple unit bands, and synchronization/broadcast channels are mapped only in specific unit bands (e.g., first and last unit bands) rather than all unit bands. This segmentation allows LTE terminals to acquire synchronization in available unit bands while reducing overall resource consumption across the wideband frequency.
Solution Approach 2:
The synchronization and broadcast channels are designed to serve multiple terminal types (both LTE and LTE+ terminals) simultaneously. By mapping these channels in a subset of unit bands, the system provides universal access points for terminal synchronization while enabling LTE+ terminals to utilize additional dynamic broadcast signals for enhanced functionality.
2Loss of energy
If synchronization and broadcast channels are mapped only in part of unit bands, then resource usage efficiency improves, but LTE terminals cannot find synchronization in all unit bands
Solution Approach 1:
Different unit bands have different qualities regarding channel mapping. The first and last unit bands are designated as having synchronization capability for LTE terminals, while intermediate unit bands may not have these channels mapped. This local quality differentiation allows efficient resource usage in intermediate bands while maintaining terminal access flexibility through available synchronization points at the band edges.
3Adaptability or versatility
If the system supports both LTE and LTE+ terminals with different bandwidth capabilities, then system versatility improves, but device complexity increases
Solution Approach 1:
The system employs dynamic signal mapping where synchronization and broadcast channels are placed in specific unit bands based on terminal capability. LTE terminals receive static channel mappings in first and last unit bands, while LTE+ terminals receive additional dynamic broadcast signals in other unit bands. This dynamic approach allows the system to adapt to different terminal capabilities without requiring complex per-terminal configuration management.
Data Source
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AI summary
Provided are a base station, a terminal, a band allocation method, and a downlink data communication method in which a mapping method for synchronization signals and report signals is implemented with high resource usage efficiency when a first system in which an independent single communication is allocated to a unit band co-exists with a second system in which a plurality of unit bands can be allocated to a single communication. In a base station (200), an OFDM signal generation unit (225) maps primary synchronization channel (P-SCH), secondary synchronization channel (S-SCH), primary broadcast channel (P-BCH), and dynamic broadcast channel (D-BCH), which can be decoded by both an LTE terminal and an LTE+ terminal, to some of a plurality of unit bands available to the station itself. The OFDM signal generation unit (225) also maps D-BCH+, which can be decoded only by an LTE+ terminal, to all of the plurality of unit bands to produce a multiplexed transmission signal. When the terminal which has transmitted terminal capability information is an LTE+ terminal, a control unit (265) transmits a band movement indication which indicates changes in the reception band to that terminal.