Beamforming Synchronization in High-Frequency Mobile Stations
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Solution Overview
Problem
High-frequency bands above 30 GHz suffer from severe signal attenuation, limiting service coverage due to distance-dependent signal loss, making it difficult to increase data rates beyond current frequency utilization efficiency limits.
Innovation Solution
A method and apparatus for a mobile station to establish synchronization with a base station using beamforming by determining propagation delays and signal strengths of downlink signals to select optimal beam pairs, thereby determining the downlink frame boundary and adjusting uplink transmission times to improve signal transmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If beamforming is used to concentrate transmission power in high-frequency bands, then transmission efficiency is improved, but service coverage is reduced due to narrow beam width
Solution Approach 1:
The base station divides the coverage area into multiple sectors and uses multiple beams to cover different spatial regions simultaneously. Each beam is directed toward a specific angular range, allowing the system to maintain high transmission efficiency in each sector while collectively providing wide coverage across all sectors through the combination of multiple segmented beams
Solution Approach 2:
The patent extends beamforming from traditional two-dimensional horizontal plane coverage to three-dimensional spatial coverage by introducing vertical beamforming capabilities. This allows the system to concentrate energy in specific three-dimensional spatial regions while maintaining overall coverage through coordinated transmission from multiple antennas in both horizontal and vertical dimensions
2Area of stationary object
If base station transmission power is increased to compensate for signal attenuation, then service coverage is improved, but energy consumption increases
Solution Approach 1:
Instead of uniformly increasing transmission power across all directions, the base station applies beamforming to concentrate transmission power only in specific angular directions where users are located. This localized power concentration achieves adequate signal strength for coverage extension while avoiding the energy waste of omnidirectional high-power transmission, thereby improving service coverage with controlled energy consumption
Solution Approach 2:
The system uses uplink reference signals from user equipment to estimate downlink channel conditions and determine optimal beamforming weights. This feedback mechanism allows the base station to adaptively adjust beam directions and power levels based on actual user locations and channel states, ensuring energy-efficient transmission that provides sufficient coverage without excessive power consumption
3Area of stationary object
If multiple beams are used to expand coverage, then service area is increased, but synchronization complexity increases
Solution Approach 1:
The base station pre-calculates and stores optimal beamforming weights for multiple beams before actual data transmission. These pre-computed weights account for different angular directions and channel conditions, allowing the system to quickly switch between pre-configured beams without real-time computation overhead, thereby simplifying synchronization procedures while maintaining multi-beam coverage capabilities
Solution Approach 2:
The patent employs a unified beamforming framework that uses the same set of beamforming weights and synchronization procedures for both downlink data transmission and uplink synchronization. This multi-functional approach allows the system to achieve wide coverage through multiple beams while using a single standardized synchronization mechanism, reducing the complexity that would otherwise arise from having separate procedures for different functions
Data Source
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AI summary
A method of establishing synchronization with a base station by a mobile station in a communication system using beamforming includes: receiving a downlink signal transmitted through at least one transmission beam by using at least one reception beam; determining at least one of a propagation delay and a signal strength of the received downlink signal for each downlink transmission/reception beam pair through which the downlink signal is transmitted/received, wherein each downlink transmission/reception beam pair includes a transmission beam through which the downlink signal is transmitted from the base station and a reception beam through which the downlink signal is received by the mobile station; and establishing a downlink frame boundary of the mobile station by using the determined at least one of the propagation delay and the signal strength for each downlink transmission/reception beam pair.