Cellular Power Mask Control for Clean OFDM Signal Ramping
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Solution Overview
Problem
Current transmission output power control in E-UTRAN networks experiences signal quality degradation and interference due to abrupt power changes during transient periods, which affects the throughput and quality of signals like the Sounding Reference Symbol (SRS) used for channel estimation and scheduling.
Innovation Solution
Adapting pre-defined power masks based on signal transmission characteristics, such as content, network conditions, and scheduling information, to optimize the position and duration of power ramps, thereby minimizing interference and ensuring high-quality signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the transmitter output power is changed abruptly between timeslots to improve responsiveness and adaptability, then the system can quickly adapt to changing channel conditions, but signal quality degrades during transient periods and interference increases to adjacent carriers
Solution Approach 1:
The transmitter performs preliminary power ramping before the actual signal transmission begins. The output power is gradually increased from a lower level to the target level during a ramping period that starts before the timeslot containing the signal, ensuring the transmitter is fully ready before transmission starts, thus avoiding signal quality degradation
Solution Approach 2:
The power ramping operation is extracted and separated from the signal transmission timeslot. The ramping occurs in a separate preliminary period, while the signal transmission occurs in a clean timeslot without ongoing power changes, thus eliminating the interference between power transitions and signal transmission
2Adaptability or versatility
If the transmitter output power is changed abruptly between timeslots to improve responsiveness, then the system can quickly adapt to channel conditions, but adjacent channel interference increases
Solution Approach 1:
The transmitter performs preliminary power ramping before the actual signal transmission begins. The output power is gradually increased from a lower level to the target level during a ramping period that starts before the timeslot containing the signal, ensuring the transmitter is fully ready before transmission starts, thus avoiding signal quality degradation
Solution Approach 2:
The power ramping operation is extracted and separated from the signal transmission timeslot. The ramping occurs in a separate preliminary period, while the signal transmission occurs in a clean timeslot without ongoing power changes, thus eliminating the interference between power transitions and signal transmission
3Reliability
If the power ramp duration is extended to improve signal quality during transitions, then signal quality improves, but the time available for actual signal transmission decreases
Solution Approach 1:
The transmitter performs preliminary power ramping before the actual signal transmission begins. The output power is gradually increased from a lower level to the target level during a ramping period that starts before the timeslot containing the signal, ensuring the transmitter is fully ready before transmission starts, thus avoiding signal quality degradation
Solution Approach 2:
The total time period is segmented into distinct phases: a preliminary ramping phase for power adjustment, and a separate transmission phase for signal delivery. This segmentation allows the ramping to occur without encroaching on the signal transmission time, as the ramping happens before the timeslot begins
4Device complexity
If power masks are defined at timeslot level to simplify control, then device complexity is reduced, but the ability to optimize signal quality for specific signals within the timeslot is limited
Solution Approach 1:
The transmitter performs preliminary power ramping before the actual signal transmission begins. The output power is gradually increased from a lower level to the target level during a ramping period that starts before the timeslot containing the signal, ensuring the transmitter is fully ready before transmission starts, thus avoiding signal quality degradation
Solution Approach 2:
The power mask is applied locally to specific signals within the timeslot, particularly to reference signals like SRS that require high quality. The system can differentiate between signal types and apply appropriate power control strategies, ensuring high-quality transmission for critical signals while maintaining overall system efficiency
Data Source
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AI summary
The present invention relates to the area of wireless communication, and especially to a method and an arrangement for transmission output power control in a cellular telecommunications network. An improved transmission output power control is achieved by adapting a pre-defined power mask to a signal transmission characteristic of the signal transmission and applying the adapted power mask to a sub-frame or an OFDM symbol. The present invention could be implemented in a network node such as an eNodeB or in a user equipment.