Power Control and Overlapping Management for Quasi-Orthogonal Systems

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Solution Overview

Problem

Multiple-access communication systems face limitations in simultaneously serving multiple terminals due to interference and resource constraints, which restricts system capacity and throughput.

Innovation Solution

Implementing power control and overlapping management techniques in a quasi-orthogonal communication system, where a base station adjusts overlapping factors and transmit power to optimize performance, manage inter-sector interference, and ensure Quality of Service (QoS) by scheduling terminals and broadcasting control parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If multiple terminals transmit simultaneously on the same time-frequency block, then system capacity increases, but interference increases and degrades signal quality

Engineering Contradiction:

Improvesystem capacityVSAvoidinterference

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the overlapping factor (number of simultaneous transmissions per time-frequency block) and transmit power levels based on channel conditions and interference measurements. The base station modifies these parameters to optimize system capacity while maintaining acceptable signal quality, directly resolving the contradiction between increasing productivity and managing harmful interference.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system implements dynamics through continuous adaptation of power control parameters and overlapping factors based on real-time channel state information and interference measurements. The base station dynamically adjusts transmit power for each terminal and modifies the number of overlapping transmissions according to varying system conditions, enabling the system to maintain optimal performance across different loading scenarios.

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If orthogonal multiplexing is used to serve multiple terminals, then interference is minimized, but system capacity is limited by available orthogonal resources

Engineering Contradiction:

ImproveinterferenceVSAvoidsystem capacity

Core Design Contradiction:

Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent applies partial or excessive action by allowing more terminals to transmit simultaneously than the number of available orthogonal codes (excessive action), accepting controlled levels of interference. The system uses power control and overlapping management to manage this partial violation of strict orthogonality, thereby increasing system capacity beyond the limitations of complete orthogonal multiplexing.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system converts the harmful effect of interference into a beneficial outcome by using interference measurements to dynamically adjust power control parameters and overlapping factors. The base station measures interference levels and uses this information to optimize resource allocation, transforming the previously harmful interference into a signal that guides system optimization and capacity enhancement.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If transmit power is increased to maintain signal quality, then signal-to-noise ratio improves, but interference to other terminals increases

Engineering Contradiction:

Improvesignal qualityVSAvoidinterference to other terminals

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent implements feedback through continuous measurement of signal quality metrics (SNR, BER) and interference levels at the base station. These measurements are fed back to adjust power control parameters and overlapping factors in real-time, creating a closed-loop system that automatically balances signal quality requirements against interference generation, resolving the contradiction between reliability and harmful effects.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system applies local quality by assigning different power control parameters and overlapping factors to different terminals and time-frequency blocks based on their specific channel conditions and interference environments. Each terminal receives customized power control adjustments tailored to its local situation, enabling the system to maintain high signal quality for individual terminals while minimizing overall interference through localized optimization.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS7512412B2Power control and overlapping control for a quasi-orthogonal communication system

Publication Date: 2009.03.31 QUALCOMM INC

AI summary

Techniques for controlling transmit power and the amount of overlapping in a quasi-orthogonal system are described. A base station for a sector receives transmissions from terminals in that sector and neighbor sectors and determines performance metrics (e.g., overall throughput) and/or QoS metrics (e.g., minimum data rate) for the terminals in the sector. The base station updates an overlapping factor based on the performance metrics and updates a QoS power control parameter based on the QoS metrics. The overlapping factor indicates the average number of overlapping transmissions sent simultaneously on each time-frequency block usable for data transmission. The QoS power control parameter ensures that the terminals in the sector can achieve minimum QoS requirements. A power control mechanism with multiple loops is used to adjust the transmit power of each terminal. The overlapping factor and QoS power control parameter are updated by two of the loops.