Autoconfiguration of the radio parameters is a key feature for next generation mobile networks. Especially for LTE the NGMN Forum has brought it up as a major requirement. It is indispensable that algorithms used for autoconfiguration terminate quickly and do not cause infinite iterative reconfigurations within the network.Reference signal sequences are among the most important radio parameters for LTE, which are comparable to scrambling codes in 3G networks. In LTE they additionally serve as Cell Identifiers on the Physical Layer. Each cell is assigned one of the 504 available Physical Cell Identifiers. For proper operation the assignment has to be as well collision as also confusion free. Due to the high number and the layered structure of the cells within the network such an assignment is a complex task.In addition to this complexity each change of the Physical Cell ID of an operational cell causes a service interruption in the cell, which has to be avoided. The approach presented maps the ID assignment problem to the well known and well understood problem of graph coloring. It is shown that an efficient initial assignment even for complex networks is possible. Cells added during the subsequent network growth, can already be confused when inserted into the network. In this case the IDs of the operational cells causing the confusion must be changed.As a next logical step the incremental approach shows how the properties of the colored graph can be used for extending the network with new cells, with only minimal interruption while still retaining the properties of a colored graph.

Future wireless networks (LTE and beyond) will experience a continuous growth regarding the number of network elements with increasingly complex interrelations between the configuration of multiple network elements (NEs). A related trend is the seamless integration of multiple radio technologies into a single heterogeneous wireless network. Both developments increase network management complexity and require new management concepts with a very high degree of automation such as Self-Organizing Network (SON) concepts, which are currently discussed in the network operator (NGMN), research, and standardization (3GPP) communities.SON functions have to be coordinated and supervised in an automated way in order to enable a stable system operation with tight control over the system behavior by the network operator together with a high degree of automation. Based on a detailed analysis of the requirements for the coordination, a policy-based approach to realize the coordination-related decision making based on the network configuration and SON function context is presented. Results for two use cases (fully automatic hardware to site mapping and coverage & capacity optimization) are presented to show the applicability of the developed approach to diverse SON use cases.

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Abstract-The trend for future mobile networks is to move away from Network Elements (NEs) delivered with specially tailored configurations towards off-the-shelf products. The configurations of NEs are automatically created with respect to their context including information on location and configuration of neighboring NEs. To minimize time-consuming and errorprone human interaction, automatic behavior is required for all stages of a NE's life cycle. The possibility to pre-assess the effects of configuration changes is inevitable in order to avoid service degradation caused by unnecessary reconfigurations. Graph coloring-based Physical Cell ID (PCID) assignment for LTE networks was introduced previously. The foundation on graph coloring theory allowed to transfer knowledge from this domain to the task of PCID assignment in order to pre-asses if an assignment is possible and how many PCIDs are required. Now the focus lies on adaptations of the basic approach to satisfy additional operator requirements such as safety margins. Those adaptations should provide equally good results in terms of used PCIDs with only minimal impact on costs and operation and maintenance tasks. Variations of the basic PCID assignment approach are discussed to address other types of problems.

Abstract-Self-Organizing Mobile Networks contain a potentially large number of SON function instances that need to be coordinated in order to achieve system-level operational goals. Many SON functions (and thus their coordination) will be realized in a centralized way (C-SON) due to the required integration with a (centralized) legacy OAM system. In such systems, many configuration requests ("batches") are treated in regular time intervals For SON functions, this may lead to undesired effects (monopolization by high priority functions and frequent rollbacks of configuration actions). This paper proposes a novel coordination approach combining an output buffer of pending configuration requests with dynamic priorities for different SON function types. A simulated network scenario exhibiting a specific optimization problem (closure of a coverage hole) is used to evaluate the proposed method. The method is able to avoid the undesired effects and approximate legacy workflows in network optimization while still keeping the autonomous characteristic of SON functions.