Dynamic Mobility Pilot Triggering for Wireless Handover
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Solution Overview
Problem
In cellular communications networks with advanced antenna systems using narrow transmission beams, continuous transmission of pilot signals for handover and beam switching is inefficient, leading to increased interference, network capacity consumption, and higher power consumption, making it difficult to maintain reliable handovers and beam updates.
Innovation Solution
A method where a radio access network node dynamically activates mobility pilot signals only when necessary, based on a performance quality metric and location-dependent criteria, allowing wireless devices to perform measurements on specific transmission beams, thereby avoiding continuous downlink pilot signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If continuous transmission of pilot signals is performed in all transmission beams, then measurement accuracy for handover is improved, but network capacity is consumed and interference increases
Solution Approach 1:
The patent implements periodic transmission of pilot signals in transmission beams instead of continuous transmission. The network node transmits pilot signals periodically in different transmission beams, allowing wireless devices to perform measurements at specific intervals. This periodic action reduces the overall quantity of pilot signals transmitted across the network while still providing sufficient measurement opportunities for accurate handover decisions.
Solution Approach 2:
The patent introduces dynamic activation of pilot signal transmission based on measurement triggers. When a wireless device detects that a performance quality metric fulfills a location-dependent criterion, it triggers the transmission of mobility pilot signals. This dynamic approach adapts the pilot signal transmission to actual network conditions and measurement needs, reducing unnecessary transmissions and conserving network capacity.
2Measurement precision
If continuous transmission of pilot signals is performed in all transmission beams, then measurement accuracy for handover is improved, but power consumption increases
Solution Approach 1:
The network node transmits pilot signals periodically rather than continuously, creating intervals where transmission is suspended. This periodic transmission pattern significantly reduces power consumption by the network node while still providing sufficient measurement opportunities for wireless devices to accurately assess transmission beam quality for handover decisions.
Solution Approach 2:
The system dynamically activates pilot signal transmission only when measurement triggers occur. The network node monitors for trigger events from wireless devices and activates mobility pilot signal transmission accordingly. This dynamic activation ensures power is consumed only when necessary for measurements, rather than continuously, reducing overall power consumption while maintaining measurement accuracy when needed.
3Measurement precision
If pilot signals are transmitted in all transmission beams simultaneously, then measurement coverage is improved, but interference in neighbor cells increases
Solution Approach 1:
The patent implements periodic transmission of pilot signals across different transmission beams rather than simultaneous transmission in all beams. The network node cycles through transmission beams periodically, transmitting pilot signals in one beam at a time or in staggered intervals. This temporal separation reduces interference in neighbor cells while still providing comprehensive measurement coverage across all beams over time.
Solution Approach 2:
The system dynamically selects which transmission beams receive pilot signal transmissions based on trigger events and network conditions. When a measurement trigger occurs, the network node activates pilot signal transmission in specific beams rather than all beams simultaneously. This dynamic selection reduces overall interference while maintaining measurement coverage for the triggered wireless device.
Data Source
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AI summary
There is provided a method for triggering mobility measurements for a wireless device. The method is performed by a radio access network node (RANN). The RANN is configurable to transmit using a set of transmission beams. The method comprises receiving signalling from a wireless device (WD). The user traffic signalling is indicative of a current position of the WD and a performance quality metric of the WD. The method comprises, only in a case the performance quality metric fulfils a location dependent performance quality criterion, activating transmission of mobility pilot signals to the WD in at least one transmission beam in the set of transmission beams. The method comprises, thereafter, instructing the WD to perform measurements on the at least one transmission beam.