Radio Apparatus Cyclic Delay Diversity Time Shift
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In MIMO systems using OFDM modulation, beacons transmitted from multiple antennas face challenges in achieving optimal directivity and correlation among subcarriers, leading to reduced data transmission rates and increased noise due to interference and channel estimation errors.
Innovation Solution
A radio apparatus generates burst signals with varying time-shift amounts for each antenna, employing Cyclic Delay Diversity (CDD) to balance directivity and correlation, allowing for switching between fixed and variable shift amounts to accommodate different requirements and enable smoothing processing across subcarriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If beacons are transmitted from multiple antennas with fixed time-shift amounts, then antenna directivity is improved, but correlation among subcarriers deteriorates
Solution Approach 1:
The patent applies dynamics by switching between fixed time-shift amounts and variable time-shift amounts depending on the transmission requirements. When omnidirectional coverage is needed, fixed time-shifts are used; when correlation is needed, variable time-shifts are applied. This dynamic adaptation resolves the contradiction between directivity and correlation stability.
Solution Approach 2:
The patent changes the time-shift parameter dynamically. By varying the time-shift amount based on transmission conditions (using either fixed or variable shifts), the system can achieve both good directivity and correlation among subcarriers, resolving the technical contradiction through parameter adaptation.
2Stability of the object's composition
If variable time-shift amounts are used for all beacons, then correlation among subcarriers is improved, but antenna directivity deteriorates
Solution Approach 1:
The system dynamically selects between fixed and variable time-shift amounts based on transmission needs. Variable shifts are used when correlation is prioritized, while fixed shifts are used when directivity is prioritized, allowing the system to adapt to different operational requirements and resolve the contradiction.
Solution Approach 2:
The time-shift parameter is changed adaptively based on transmission conditions. The system switches between fixed and variable time-shift amounts, enabling optimization of either correlation or directivity depending on the specific transmission scenario, thus resolving the contradiction between these two parameters.
3Shape
If fixed time-shift amounts are used, then antenna directivity is improved, but adaptability to different transmission requirements deteriorates
Solution Approach 1:
The system implements dynamics by making the time-shift configuration changeable based on transmission requirements. The base station can switch between fixed and variable time-shift amounts, providing adaptability to different transmission scenarios while maintaining good directivity performance.
Solution Approach 2:
The time-shift parameter is made changeable based on transmission conditions. The system can adaptively select between fixed and variable time-shift amounts, enhancing versatility and adaptability to different transmission requirements while preserving directivity performance.
4Area of stationary object
If multiple beacons with different time-shifts are transmitted, then coverage is improved, but system complexity increases
Solution Approach 1:
The system uses dynamic time-shift configuration where the base station switches between fixed and variable time-shift amounts based on transmission needs. This dynamic approach expands coverage effectively while avoiding unnecessary complexity by using the simpler fixed mode when sufficient.
Solution Approach 2:
The time-shift parameter is changed adaptively to balance coverage and complexity. By switching between fixed and variable time-shift amounts, the system achieves expanded coverage when needed while maintaining simplicity in routine operations, thus resolving the contradiction between coverage area and system complexity.
Data Source
AI summary
A plurality of antennas respectively conveys burst signals that use a plurality of subcarriers and contain control information for communications. When a plurality of subcarriers are used, a cyclic time shifting in a cycle in time domain is executed, per antenna, with a time-shift amount corresponding to each of the plurality of antennas. A control unit generates the burst signals informed from the plurality of antennas by complying with this rule. The control unit generates the burst signals by varying time shift amounts corresponding respectively to the plurality of antennas.