NLOS Backhaul Beamforming for Self-Alignment and Interference Cancellation
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Solution Overview
Problem
Current wireless backhaul systems lack self-alignment and realignment of antenna beams, fail to operate in non-line-of-sight environments, and do not effectively cancel interference, leading to reduced spectral efficiency and link reliability, which is inadequate for the increasing capacity demands of modern wireless networks.
Innovation Solution
A non-line of sight wireless backhaul system that enables self-alignment of antenna beams, uses extreme interference cancellation, and multi-target beamforming to enhance spectral efficiency, allowing operation in various propagation environments and reducing interference, thereby increasing link reliability and capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional point-to-point microwave backhaul systems are used with high gain parabolic dishes, then link reliability is maintained in line-of-sight conditions, but the system cannot operate in non-line-of-sight environments and requires manual alignment
Solution Approach 1:
The system employs adaptive beamforming that dynamically adjusts antenna weight vectors in response to changing propagation conditions. The beamforming weights are continuously optimized to track the desired signal direction and cancel interference from multiple paths, enabling the system to adapt to non-line-of-sight environments without manual realignment.
Solution Approach 2:
The system performs self-alignment through automatic beamforming optimization. The antenna array automatically adjusts its beam patterns and weight vectors to maximize signal reception and minimize interference, eliminating the need for manual alignment operations while maintaining optimal performance in varying propagation conditions.
2Reliability
If high gain parabolic dishes are used to maintain link reliability, then spectral efficiency is limited due to co-channel interference, but reducing dish gain would further reduce link reliability
Solution Approach 1:
The system converts harmful multipath interference and co-channel signals into useful information by using them as reference signals for beamforming optimization. The interference from multiple propagation paths is processed to extract spatial characteristics, which are then used to form directional beams that enhance spectral efficiency while maintaining link reliability.
3Productivity
If interference cancellation techniques are implemented to increase spectral efficiency, then system complexity increases, but without interference cancellation spectral efficiency remains limited
Solution Approach 1:
The system merges beamforming and interference cancellation into a unified adaptive spatial processing framework. The same antenna weight vectors that form directional beams also provide interference rejection, eliminating the need for separate interference cancellation hardware and reducing overall system complexity while achieving high spectral efficiency.
4Loss of time
If manual alignment of antenna beams is performed to ensure proper positioning, then initial setup time is reduced, but the system cannot perform realignment when propagation conditions change
Solution Approach 1:
The system performs preliminary beamforming optimization during initial setup to quickly establish connectivity, then continuously monitors propagation conditions and automatically re-optimizes beam patterns in real-time. This preliminary action followed by continuous adaptation eliminates both manual realignment requirements and setup time delays.
Data Source
AI summary
A non-line of sight backhaul system and method are described that provides self-alignment of the antennas beams of the wireless radios of the system, that provides robust operation in licensed and unlicensed frequency bands, that facilitates the use of a reduced number of frequency channels from M to 1 and that enables operation in a non-line of sight (NLOS) propagation environment.