Uplink Closed-Loop Beamforming With Multi-Base-Station Phase Feedback
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Solution Overview
Problem
In mobile wireless communication systems, during soft handoff situations where a mobile device receives feedback signals from multiple base stations, obeying the feedback from the serving base station can cause interference with nearby non-serving base stations, leading to suboptimal communication performance.
Innovation Solution
The mobile device calculates a modified value of the phase parameter based on feedback from a non-serving base station, adjusting it in a direction opposite to the feedback received, to minimize interference with the non-serving base station while maintaining optimal communication with the serving base station through null beamforming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile device obeys the feedback signals from the serving base station to optimize reception quality, then the reception quality at the serving base station is improved, but interference with non-serving base stations increases
Solution Approach 1:
The mobile device calculates a modified phase parameter that preemptively counteracts the harmful interference effect. By modifying the phase parameter in the opposite direction of what the serving base station feedback indicates, the device creates destructive interference at non-serving base stations before the interference can significantly impact the network, thus preventing harmful effects in advance
Solution Approach 2:
The invention converts the harmful interference into a beneficial effect by using the same transmit diversity mechanism to create destructive interference at non-serving base stations. The phase modification that would normally improve serving base station reception is adjusted to simultaneously create nulls in the direction of non-serving base stations, turning potential harm into a benefit by reducing overall network interference
2Reliability
If the mobile device transmits diversity signals with optimized phase parameters for the serving base station, then signal quality at the serving base station is improved, but signal loss or suboptimal reception at non-serving base stations occurs
Solution Approach 1:
The mobile device applies different phase parameter strategies for different target base stations. By calculating a modified phase parameter specifically tailored to reduce interference at non-serving base stations while maintaining adequate signal quality at the serving base station, the system creates localized optimization - destructive interference in specific directions (toward non-serving base stations) while preserving useful signal transmission to the intended recipient
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 interference with non-serving base stations and enhances the overall communication quality by adjusting the transmit diversity signals to destructively interfere at the non-serving base station, thereby improving the signal reception at the serving base station.
Implementation Method 1
The signals combine at a base station... to perform beamforming so as to optimize reception quality... calculate a modified value of the phase parameter... in a direction opposite to a direction indicated by the feedback signal... transmit a modified diversity signal
Data Source
AI summary
A method, apparatus, and system for transmitting and controlling uplink diversity signals in a mobile communication device. While in a soft handoff situation, a mobile communications device may receive a phase feedback signal from a non-serving base station. The mobile device may calculate a modified phase parameter based on the phase feedback signal from the non-serving base station in order to minimize interference with the non-serving base station, for example, by calculating a modified value of a phase difference in a direction opposite to the direction desired by the non-serving base station. In some embodiments of the invention, the mobile device may determine whether to calculate the modified phase parameter in a direction opposite to the direction indicated by the phase feedback signal of the non-serving base station based on a comparison of power feedback signals received from the non-serving and serving base stations.