Cellular Power Mask Adaptation for OFDM Interference Control
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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 performance and throughput of cellular telecommunications systems.
Innovation Solution
A method and arrangement for setting and adapting a pre-defined power mask for sub-frames and OFDM symbols, defined by parameters such as starting and ending points, durations, and power levels of power ramps, to optimize signal transmission characteristics and minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the transmitter is turned on slightly before the actual signal is transmitted to allow the transmitter to reach the on state, then the signal quality is improved, but energy is transmitted outside the timeslot causing interference to other user equipment
Solution Approach 1:
The transmitter is turned on before the actual signal transmission to allow the power ramp to complete, ensuring high signal quality. The patent applies this by initiating the power ramp in advance of the scheduled transmission time, allowing the transmitter to reach its on state before data transmission begins.
Solution Approach 2:
The harmful transient period is extracted and separated from the actual data transmission timeslot. The patent implements this by allowing the power ramp to occur in a separate time period before the scheduled transmission, isolating the interference-generating phase from the data-carrying phase.
2Object-generated harmful factors
If the transmitter is turned off before the transmission of the signal has been completed, then adjacent channel interference is reduced, but the signal transmission quality deteriorates due to abrupt power changes
Solution Approach 1:
The power ramp-down is initiated in advance of the scheduled transmission end time. The patent applies this by planning the transmitter shutdown before the transmission period ends, allowing the power to decrease gradually rather than abruptly, thus maintaining signal quality while reducing interference.
Solution Approach 2:
The transmitter power is made dynamic during the transition periods. The patent implements this by allowing the power to change gradually during ramp-up and ramp-down phases, rather than maintaining a fixed on/off state, thereby smoothing the transitions and reducing abrupt power changes.
3Ease of manufacture
If a fixed power mask is applied to all transmissions, then implementation is simple, but it cannot optimize signal quality for different signal types and transmission conditions
Solution Approach 1:
The power mask parameters are made dynamic and adaptable to different transmission conditions. The patent implements this by allowing the power mask to be adjusted based on the specific signal type, transmission timing, and channel conditions, rather than applying a static mask to all transmissions.
Solution Approach 2:
Different power mask parameters are applied to different parts of the transmission. The patent applies this by using separate parameters for ramp-up and ramp-down phases, and by allowing different power mask configurations for different signal types (e.g., reference signals vs. data transmissions), optimizing each locally rather than using a global fixed mask.
Data Source
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.