To minimize or eliminate planning, small cells need to be able to configure themselves at startup and continue to do so during regular operations.
A small cell has to select its Physical Cell Identity (PCI) such that there is no collision with PCIs of its neighbors. Small cells may use Network Listen to detect PCIs that are used by neighbors. They can then choose from PCIs that are not already in use. The decision can be enhanced by UE reports, which contain PCIs of cells in vicinity, and X2 messages from other cells nearby.
A small cell also has to maintain its neighbor cell list to facilitate handovers of UEs to other cells. Network Listen can also be used here to discover neighboring cells. Reports from UEs and message exchange with other cells via X2 will both further enhance the neighbor cell list by adding cells that are not detected through Network Listen.
UltraSON is capable of autonomously detecting and resolving PCI conflict and confusion between neighboring cells, including serving cell having the same PCI as a direct neighboring cell, and two neighboring cells of the same serving cell having the same PCI. Network Listen results, UE reports, X2 messages, and other relevant KPIs are used to detect and resolve PCI conflicts.
UltraSON self-configuration feature is capable of storing the self-derived configuration parameters and deciding, upon a reboot, whether to re-use these parameters or initiate new self-configuration based on various factors. This avoids delays in start-up and stabilizes operation by avoiding unnecessary self-configuration in scenarios when the surrounding RF environment has not changed after a reboot.