Lester Tse Wee Ho

Applying emergent self-organizing behavior for the coordination of 4G networks using complexity metrics

Future fourth-generation (4G) wireless networks are expected to have an ad hoc, dynamic structure with cheap, ubiquitous, low-powered nodes that are autoconfigurable and flexible. Controlling such a network means coping with uncertainty, not only of traffic demand, but also in the network structure. Because of this, a new approach to the control and coordination of 4G networks will be needed, one that replaces centralized with highly decentralized control. One promising approach is to view networks as self-organizing systems comprising simple interacting nodes that rely on emergent behavior to provide network-wide coordination. However, such networks are often difficult to predict or manipulate, due to their distributed nature. This paper describes the use of an entropy-based complexity metric to investigate and manipulate the behavior of such self-organizing systems in mobile networks. We introduce a self-organizing algorithm for cell dimensioning, and apply the complexity metric to extract information on network-wide behavior. We then introduce a framework for using the metric to manipulate emergent self-organizing behavior in 4G networks.

Coordination of SON Functions in Multi-Vendor Femtocell Networks

With the increase of network complexity, there is a high need for network management automation. This is achieved through SON principles that enable self-configuration, self-optimization, and self-healing. However, even though SON functions are meant to be autonomous, a high level of coordination among them is required. To this end, efficient conflict detection and resolution techniques are needed, especially in multi-vendor deployments. This article presents a design together with a sample implementation of a coordination scheme between three key SON functions in femtocell networks: cell ID assignment, coverage adjustment, and idle mode control. This ensures stability and continuity of the network operation even in a situation when the functions have contradicting objectives. The solution is based on the Broadband Forum TR-069 protocol and is applicable to multi-vendor networks. Simulation evaluation has shown that SON coordination reduces mean cell ID conflicts by over 30 percent and, resulting from that, call drop probability by over 40 percent.