Base Station Timing Offset Adjustment for PCI Conflict Resolution
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Solution Overview
Problem
In cellular communications networks, the limited number of Physical Cell Identifiers (PCIs) leads to conflicts and interference issues, particularly in dense deployments like femtocell networks, where PCI collisions and confusions result in unstable connections, reduced data throughput, and increased service disruptions.
Innovation Solution
A method for base stations to determine and adjust their periodic timing pulses to maintain a relative timing offset, reducing the rate of change and avoiding periodic synchronization, which minimizes interference by ensuring that reference signals are not transmitted at the same time, thereby mitigating PCI conflicts and associated performance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If base stations use the same PCI value to increase network capacity and coverage, then network density and capacity are improved, but PCI conflicts (collisions and confusions) occur leading to unstable connections and reduced data throughput
Solution Approach 1:
The patent changes the timing parameter (frame transmission time) of base stations to resolve PCI conflicts. By adjusting the frame transmission time of interfering base stations, the system maintains PCI reuse for capacity while avoiding simultaneous transmissions that cause conflicts, thus preserving connection stability.
2Productivity
If base stations are synchronized to improve network coordination, then network efficiency is improved, but interference spikes occur when base stations with same mod 3 PCI values transmit reference signals simultaneously, reducing data throughput
Solution Approach 1:
The patent changes the timing parameter (frame transmission time) of base stations to resolve PCI conflicts. By adjusting the frame transmission time of interfering base stations, the system maintains PCI reuse for capacity while avoiding simultaneous transmissions that cause conflicts, thus preserving connection stability.
Solution Approach 2:
The patent introduces periodic desynchronization by adjusting frame transmission times in a periodic manner. This ensures that base stations with conflicting PCIs do not transmit reference signals simultaneously, reducing interference spikes while maintaining overall network synchronization for efficiency.
3Reliability
If the number of PCIs is increased to eliminate conflicts, then PCI collision probability is reduced, but the complexity of PCI allocation and management increases
Solution Approach 1:
The patent uses frame transmission time as an intermediary parameter to resolve PCI conflicts. Instead of increasing the number of PCIs or complicating allocation algorithms, the system uses timing adjustment as a mediator to separate transmissions from base stations with same mod 3 PCI values, simplifying PCI management.
4Ease of manufacture
If base stations operate independently to simplify network management, then deployment complexity is reduced, but PCI conflicts occur more frequently due to lack of coordination, reducing network performance
Solution Approach 1:
The patent enables base stations to autonomously adjust their frame transmission times based on detected PCI conflicts. Each base station independently identifies conflicts with neighboring stations and self-adjusts its timing, eliminating the need for complex centralized coordination while reducing PCI conflict frequency.
Data Source
AI summary
This disclosure provides a base station for a cellular network, and a method of operating the base station in the cellular network, the cellular network also including a second base station, wherein the first and second base stations include first and second oscillators providing a first and second periodic timing pulse respectively, the method including determining a relative timing offset between a first instance of the first periodic timing pulse for transmission of a frame from the first base station and a first instance of the second periodic timing pulse for transmission of a frame from the second base station; determining that the relative timing offset is changeable; and adjusting the first periodic timing pulse to maintain the relative timing offset by varying a first period between instances of the first periodic timing pulse such that the rate of change of the relative timing offset over time is reduced.