Antenna Weight Vector Control for Millimeter Wave Side Lobe Suppression
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Solution Overview
Problem
In wireless communication systems using millimeter waves, the disconnection time during switching between direct and reflected waves is prolonged due to the need to search for optimal beam directions, which is undesirable for real-time applications like non-compressed image transmission, and the presence of side lobes in antenna arrays complicates the determination of optimal antenna weight vectors.
Innovation Solution
A method for controlling the antenna array weight vectors by scanning beam directions, determining directions of arrival or departure, and comparing signal characteristics to identify optimal beam settings, while mitigating the effects of side lobes by using a training signal and null pointing to reduce peak emergence from side lobes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beam direction scanning is performed to determine optimal antenna weight vectors, then communication reliability is improved, but transmission disconnection time is prolonged
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing multiple candidate antenna weight vectors corresponding to different beam directions before actual communication begins. When the direct wave is blocked, the system can immediately switch to a pre-computed reflected wave path without performing real-time beam scanning, thus maintaining communication reliability while minimizing disconnection time.
Solution Approach 2:
The patent implements dynamics by enabling adaptive switching between different antenna weight vectors based on the propagation environment. The system dynamically selects between direct wave paths and reflected wave paths by monitoring signal quality and transitioning to pre-computed alternative beam configurations when blockage is detected, optimizing both reliability and response time.
2Reliability
If narrow beam forming is used to increase directive gain for reflected waves, then received signal level is improved, but beam direction search time is prolonged
Solution Approach 1:
The patent applies preliminary action by pre-computing narrow beam antenna weight vectors for multiple potential reflected wave paths in advance. These pre-calculated beam configurations are stored as candidate vectors, allowing the system to immediately activate an optimized narrow beam for reflected wave communication without performing time-consuming real-time beam direction searches when the direct path is blocked.
3Measurement precision
If side lobe effects are considered in antenna array design, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies the taking out principle by extracting and separately handling the side lobe effect compensation from the main antenna weight vector calculation. The system uses a dedicated side lobe correction matrix that is pre-computed based on antenna array characteristics, allowing precise direction of arrival determination through simple matrix multiplication without increasing the complexity of the main beam forming architecture.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the time required to set optimal beam directions, thereby minimizing transmission disconnection times and alleviates the adverse effects of side lobes, enabling more efficient and reliable wireless communication.
Implementation Method 1
a plurality of antenna elements 405-1 to 405-M... radiating electromagnetic waves
Implementation Method 2
beam forming... changing at least one of amplitudes and phases of transmission signals or received signals
Implementation Method 3
receiving electromagnetic waves... direction of arrival (DOA)... direction of departure (DOD)
Data Source
AI summary
To suppress adverse effects caused by side lobes of an antenna array when an AWV to be used for communication is determined based on a transmission/reception result of a training signal. A first transceiver generates a fixed beam pattern and transmits a training signal. In that state, a second transceiver receives the training signal while scanning for the main beam direction, and thereby determines a plurality of direction of arrivals (DOAs). Next, the second transceiver receives the training signal in a state where the signal receptions from the plurality of DODs are restricted one by one (e.g., a null direction or a direction close to the null direction is fixed in the DOA), and calculates the change of the signal characteristics from that obtained in the first reception. The transceivers obtain and use at least one AWV having the main beam direction or a sub-beam direction close to the main beam pointing to one of the plurality of DOAs except for the DOA for which the change is lower than a predefined threshold.