Phase Rotation Weights for Common Signal Transmission
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Solution Overview
Problem
In cellular communication systems, the transmission of common signals by multiple sectors can lead to distorted antenna beam patterns and reduced signal power at sector boundaries, resulting in performance deterioration, especially when sectors use the same sequence for synchronization channels.
Innovation Solution
Implementing phase rotation weights for each sector or base station based on transmission time and pattern numbers to generate unique transmission signals, which are then multiplied by beam forming weights for antennas, ensuring distinct phase patterns for each sector or base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all sectors in one base station transmit the common signal with the same phase, then the common signal coverage is improved, but the transmit antenna beam pattern is distorted and signal power decreases at sector boundaries
Solution Approach 1:
The patent applies different phase rotation weights to different sectors transmitting the common signal. Specifically, sectors are assigned different phase rotation values (e.g., 0°, 120°, 240°) so that while each sector maintains its signal transmission, the combined beam pattern at sector boundaries does not experience complete cancellation. This local differentiation of phase quality resolves the contradiction between maintaining common signal coverage and avoiding beam pattern distortion.
2Ease of operation
If neighboring sectors use the same sequence for the primary synchronization channel, then the terminal detection complexity is reduced, but the cell search performance is deteriorated due to coherent detection interference
Solution Approach 1:
The patent changes the phase parameter of the synchronization signal by applying different phase rotation weights to different sectors. Even though neighboring sectors may use the same base sequence for the primary synchronization channel, the applied phase rotations (e.g., 0° for one sector, 180° for another) create distinguishable signals at the receiver, thereby improving cell search performance while maintaining sequence simplicity.
3Object-generated harmful factors
If different sectors use different phase rotation weights, then the beam pattern distortion is reduced, but the system complexity increases due to weight management
Solution Approach 1:
The patent employs periodic phase rotation weight patterns that repeat over time. The phase rotation weights follow predetermined patterns (e.g., cyclic sequences of 0°, 120°, 240°) that are applied periodically to sectors transmitting common signals. This periodic approach reduces system complexity by using repeating patterns rather than requiring complex adaptive weight management, while still effectively preventing beam pattern distortion.
Data Source
AI summary
When a plurality of sectors transmit the same signal in a communication system, the same signal is transmitted after a weight is applied to the same signal. At this time, defective reception of the same signal in a terminal may be reduced by setting a weight pattern differently according to a symbol transmission time and a sector number.