Uplink Time Alignment Maintenance via Adaptive Power Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In wireless communication systems using uplink coordinated multipoint (UL CoMP) reception, the uplink signal quality in the serving reception point can degrade, leading to failures in uplink time alignment measurements, particularly in heterogeneous network deployments with significant downlink/uplink imbalances.
Innovation Solution
Implementing a method that ensures adequate timing measurements and maintains uplink time alignment by introducing a fixed power regulation threshold to limit signal degradation in the serving reception point, adaptive power regulation, and adaptive uplink scheduling, which allows for power control based on signal quality indicators and scheduled bandwidth adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If transmit power is controlled based on the reception point with the highest received signal quality, then interference towards low power reception points is reduced, but uplink time alignment measurements in the serving reception point deteriorate
Solution Approach 1:
The patent applies local quality by implementing different power control strategies for different reception points. The serving reception point uses a first power control scheme that prioritizes maintaining uplink time alignment measurements, while non-serving reception points use a second power control scheme that prioritizes interference reduction. This localized differentiation resolves the contradiction by allowing each reception point to optimize for its specific function.
Solution Approach 2:
The patent segments the power control function into separate mechanisms for serving and non-serving reception points. By dividing the power control into distinct control loops - one for the serving reception point and another for non-serving reception points - the system can independently optimize each function without compromising the other, thus resolving the contradiction between interference reduction and measurement accuracy.
2Reliability
If UL CoMP reception is used to improve uplink performance, then service quality is maintained with reduced transmit power, but signal quality in the serving reception point falls below acceptable levels
Solution Approach 1:
The patent segments the reception function into serving reception point and non-serving reception points with distinct roles. The serving reception point focuses on maintaining measurement quality for uplink time alignment, while non-serving reception points contribute to signal combining for overall service quality. This segmentation allows UL CoMP to improve service quality without compromising the serving reception point's measurement capability.
Solution Approach 2:
The patent applies local quality by implementing differentiated power control for the serving reception point versus non-serving reception points. The serving reception point receives enhanced power control to maintain acceptable signal quality for measurements, while other reception points operate with power control optimized for interference management. This resolves the contradiction by ensuring local optimization at each reception point.
3Object-generated harmful factors
If transmit power is reduced to maintain service quality in heterogeneous networks, then interference towards pico RBS is reduced, but uplink time alignment measurements fail
Solution Approach 1:
The patent segments power control into macro RBS-specific and pico RBS-specific control mechanisms. The macro RBS implements a power control scheme that ensures minimum signal quality for uplink time alignment measurements, while simultaneously managing interference towards pico RBS through coordinated power adjustments. This segmentation resolves the contradiction by decoupling the measurement reliability function from the interference management function.
Data Source
Figure 1~2
Figure 3~5
AI summary
The disclosure relates to a method (20) for maintaining uplink time alignment performed in a network node (12) of a communication system (10) comprising a first reception point (35) and a second reception point (36). The network node (12) is configured to control the first reception point (35) and configured to serve a communication device (14). The method (20) comprises determining (21) transmit power of the communication device (14) based on signaling from the communication device (14) received in the second reception point (36), while meeting a criterion enabling performing of an uplink time alignment measurement towards the first reception point (35). The disclosure also relates to corresponding network node, computer program and computer program product.