Base Station Phase Sweep Transmit Diversity Frequency Offset
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Solution Overview
Problem
In wireless communication systems, phase-sweep transmit diversity (PSTD) techniques face challenges due to synchronized sweeping frequencies among neighboring base stations, leading to low signal-to-interference plus noise ratio (SINR) in certain areas, which can result in reduced data throughput for high-speed data systems and increased base station transmit power, thereby reducing system capacity.
Innovation Solution
The method involves setting the variation rate of the imposed time-varying phase, or sweeping frequency, to differ from neighboring base stations by incorporating a differentiating component such as a randomly generated frequency offset or a parameter-specific offset, ensuring the sweeping frequency is not an integer multiple of other base stations' frequencies, thereby creating distinct phase sweeps for each antenna.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If synchronized sweeping frequencies are used among neighboring base stations, then system coordination and simplicity are improved, but signal-to-interference plus noise ratio (SINR) deteriorates in certain areas
Solution Approach 1:
The patent applies asymmetry by configuring different sweeping frequencies for different base stations. Specifically, each base station is assigned a unique sweeping frequency that is not an integer multiple of other base stations' sweeping frequencies, breaking the symmetry that causes synchronized beam patterns and interference. This asymmetric frequency configuration ensures that signal and interference beams do not sweep to the same areas simultaneously, thereby improving SINR while maintaining system coordination through controlled frequency differentiation.
Solution Approach 2:
The patent changes the frequency parameter of the phase sweeping signal to resolve the contradiction. By adjusting the sweeping frequency to be non-integer-multiple relative to other base stations, the system transforms the original synchronized frequency parameter into differentiated frequency parameters. This parameter change prevents constructive interference patterns while maintaining the diversity benefit of phase sweeping, thus improving SINR without sacrificing system coordination.
2Device complexity
If same sweeping frequency is used among neighboring base stations, then implementation complexity is reduced, but data throughput deteriorates due to low SINR
Solution Approach 1:
The patent introduces asymmetry in sweeping frequency configuration across base stations. Each base station uses a distinct sweeping frequency that avoids integer multiple relationships with others, creating asymmetric beam sweeping patterns. This approach maintains relatively simple implementation through standardized frequency offset configurations while preventing synchronized interference, thereby preserving data throughput performance.
Solution Approach 2:
The patent utilizes periodic phase sweeping action with differentiated periods or frequencies for different base stations. By configuring sweeping frequencies that are not integer multiples of each other, the periodic beam sweeping actions of different base stations become desynchronized. This prevents persistent low SINR conditions and maintains high data throughput while keeping the periodic nature of the diversity technique intact.
3Device complexity
If synchronized sweeping frequencies are employed, then base station configuration simplicity is improved, but system capacity deteriorates due to increased transmit power requirements
Solution Approach 1:
The patent changes the frequency parameter configuration to resolve the contradiction between configuration simplicity and system capacity. By setting sweeping frequencies to non-integer-multiple relationships, the system prevents scenarios where synchronized beams cause persistent interference requiring increased transmit power. This parameter adjustment maintains relatively simple base station configuration through standardized frequency offset settings while preserving system capacity by avoiding power escalation.
Data Source
AI summary
In the method, a phase of at least one signal transmitted from a transmit antenna of a base station is shifted based on a sweeping frequency having a differentiating component.