When you have a Self-Organizing/Self-Optimizing “SON” system like the E-RAN implements, it does most of the “heavy lifting” when commissioning the system. Self-organizing and self-optimizing features (SON) optimize the user experience as well as system management. A network can be set up in a matter of days by installers with Wi-Fi experience rather than macro cellular RF experts. SpiderCloud’s Self Organizing Network (SON) capability configures and optimizes the SpiderCloud small cell network to provide a high-performance mobile broadband coverage with very little user intervention. SON is a core product feature that dramatically reduces installation time, fine-tunes the network for high performance, and periodically optimizes the environment to maintain effective network operation. Without this feature, an installer would have to setup the network manually, requiring many weeks (depending on the network complexity) to create an optimal working configuration.
Besides reducing time-to-install, the feature ensures optimal RF coverage and handoff within the SpiderCloud network and with macro and inter-RAT networks. During network operation, this feature continually monitors the RF environment, makes adjustments to the radio transmit power to adapt to any changes in the RF conditions, and maintains optimal network access.
SON Architecture and External Interfaces
The E-RAN’s SON capabilities include discovering the macro cells in the area, discovering the internal small cell topology, assigning UMTS primary scrambling codes and LTE physical cell identifier, setting maximum transmit power levels, and automatically configuring cell neighbor lists to make the system operational.
The SON algorithms are centrally anchored on the local controller, the services node. The services node orchestrates the SON process, controls the operation of different radio nodes during neighbor discovery, gathers information from different radio nodes and creates optimized neighbor lists based on information received from the neighbor scans. During macro-network topology discovery, the services node ensures that the small cell network is quiet to ensure optimal macro topology discovery. During the small cell network topology discovery, the services node ensures that the small cell can detect each other accurately by coordinating scans between the small cells. The neighbor lists are constructed to optimize the system for soft handover as well as ensure smooth mobility in and out of the network.
Periodic Optimization and Self-Maintenance
While the system is in operational mode, a power optimization feature is used to periodically adjust the transmit power levels in order to achieve uniform coverage across the small cell deployment. The algorithm takes into account several factors:
- The interference level from macro networks as measured by the radio nodes
- The relative signal strength at which each radio node measures neighboring radio nodes
- • Periodic signal quality measurements made by user devices across the network and reported back to the services node
The service node uses measurements collected over time to fine-tune the network. For example it might reduce the power level of a congested cell to decrease the number of users on that cell, while powering up lightly loaded cells. The system can also be configured to periodically monitor for changes in topology (added or deleted external and internal cells) and changes in the physical RF environment of the deployment area. For example, the system can be configured to go into scan mode during weekends, when no traffic is expected on the network.