LoS-MIMO Modulation Selection for Stable Parallel Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LoS-MIMO technology, the channel capacity changes significantly when the distance between transmission and reception antennas changes, making it difficult to maintain a parallel transmission line and increase transmission capacity in applications like undersea communication.
Innovation Solution
A radio communication system with a communication distance measurement unit, a selection unit that chooses a common modulation scheme for all frequency channels based on the measured distance, and a transmission signal generation unit that separates and modulates data to maintain orthogonality and desired bit error rates, ensuring stable channel capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LoS-MIMO technology is used to form orthogonal parallel transmission lines in a line-of-sight environment, then spatial multiplex transmission capacity is improved, but the channel capacity changes significantly when the distance between transmission and reception antennas changes, making it difficult to maintain stable transmission
Solution Approach 1:
The patent applies dynamics by making the antenna spacing adjustable rather than fixed. The transmission antenna spacing and reception antenna spacing are dynamically changed based on the communication distance to maintain the orthogonality condition (Equation 1) across varying distances. This allows the system to adapt to changing environmental conditions while preserving the high channel capacity benefits of LoS-MIMO spatial multiplex transmission.
Solution Approach 2:
The patent changes physical parameters (antenna spacing) to maintain optimal performance. By adjusting the transmission antenna spacing d_T and reception antenna spacing d_R according to the communication distance D, the system maintains the geometric relationship required for orthogonality. This parameter adaptation ensures that the channel capacity remains stable even as the distance between transmission and reception antennas varies, resolving the contradiction between achieving high transmission capacity and maintaining reliability.
2Manufacturing precision
If fixed antenna spacing is used to establish orthogonality at a specific distance, then the geometric condition for orthogonal transmission lines is satisfied, but the system cannot adapt when the communication distance changes
Solution Approach 1:
The system transitions from static to dynamic antenna spacing. The transmission antenna spacing and reception antenna spacing are no longer fixed but are dynamically adjusted based on the measured communication distance. This dynamic adjustment mechanism allows the system to maintain precise geometric relationships (orthogonality condition) across varying distances, simultaneously achieving manufacturing precision in the geometric condition and adaptability to distance changes.
Solution Approach 2:
The patent implements feedback by measuring the communication distance and using this information to adjust the antenna spacing. The system continuously monitors the distance between transmission and reception antennas and adjusts the spacing parameters accordingly to maintain the orthogonality condition. This feedback loop ensures that the geometric precision is maintained while adapting to changing communication distances.
Data Source
AI summary
A radio transmission apparatus includes a communication distance measurement unit configured to measure a distance between a plurality of transmission antennas and a plurality of reception antennas, a selection unit configured to select a modulation scheme common to all frequency channels, the modulation scheme satisfying an average value of index values for each of the frequency channels according to a measured distance and satisfying a predetermined desired bit error rate, a transmission signal generation unit configured to separate transmission data, modulate each item of the separated transmission data by the selected common modulation scheme, and output the transmission signals multiplexed by the number of multiplexing indicating the number of the plurality of transmission antennas to be used. A radio reception apparatus includes a demodulation unit configured to demodulate a reception signal by a demodulation scheme corresponding to the modulation scheme to generate reception data.