Miguel Ángel Díaz-Guerra

A roadmap from UMTS optimization to LTE self-optimization

Self-Organizing Networks (SON) are currently being introduced by the 3rd Generation Partnership Project (3GPP) as part of the Long Term Evolution (LTE) system as a key driver for improving the operation of wireless networks. Given that many challenges have been identified when moving from the SON concept to practical implementation, this article claims the suitability to gain insight into the problem by taking advantage of optimization mechanisms in live Universal Mobile Telecommunications System (UMTS) networks. From that perspective, this article outlines a roadmap from actual manual optimization toward the inclusion of SON concepts in future networks. In particular, an optimization framework is developed considering different stages that include the collection of inputs from different sources (network counters, measurement reports, drive tests), the tuning parameters to achieve optimization, and the optimization procedure itself. Even though the proposed framework is presented and evaluated for convenience in a UMTS context, it is rather generic and technology-agnostic and, therefore, it can be formulated as an initial reference for LTE self-optimization use cases. The proposed framework is applied to a practical coverage optimization use case supported by data extracted from a real UMTS network in a European city, illustrating the capability to automatically identify a cell with sub-optimal coverage and to provide a solution to the problem. The extension of the case study to LTE is also analyzed. Finally, as a result of the lessons learned, the article makes a projection to the LTE context by identifying the key points to be solved for the materialization of a self-optimization procedure.

Using measurements extracted from GSM/UMTS networks for 3G planning and RRM evaluation

This paper describes a simulation tool developed for 3G planning suitable also for some RRM strategies evaluation. The innovative issue is that the simulator is based on data extracted from real GSM/UMTS networks. Considering the extensive use of GSM/UMTS co-siting for 3G network deployment, an accurate representation of propagation, mobility as well as traffic distribution is achieved compared to classical statistical and modeling approaches in simulators. Results presented reveal that the availability of real data is highly valuable since it provides a more detailed view of the network behavior and performance.

A new methodology for RF failure detection in UMTS networks

The optimization of third-generation mobile communication systems has become an important aspect for network operators. This paper proposes a new methodology for RF failure detection in UMTS networks based on key performance indicators (KPI) which are obtained by measuring certain parameters at different network entities. With the proposed methodology possible uplink problems are identified. The proposed method has been validated with data extracted from a real UMTS network.

Interactions among UMTS microcells and macrocells supporting data traffic in a real airport scenario

This paper analyses a solution to provide UMTS coverage in a real airport scenario by reusing the existing GSM infrastructure. In this case, macrocell and microcell layers are highly decoupled in terms of interference, so it is shown that CPICH power adjustment does not play a significant role in interlayer traffic distribution. On the other hand, with respect to in-building coverage, it has been observed that by reducing the number of repeaters per microcell an increase in capacity can be obtained.

Analysing UTRA-FDD pilot power and active set configuration in a real urban scenario

Assuming the use of GSM/UMTS co-sitting for initial 3G network deployment, real data extracted from the GSM network can be used to optimise 3G planning and RRM issues. It has been developed a 3G planning simulation tool which instead of using theoretical models, benefits from the availability of realistic propagation, mobility, as well as spatial and temporal traffic distributions. The tool is used in this paper to study the effects of pilot power and active set parameters in both, uplink and downlink capacity, in a real urban scenario, thus anticipating the expected behaviour of UTRA-FDD in such conditions.

An analysis of deployment alternatives in a real UMTS scenario to support voice and data traffic

This paper focuses on the deployment of UMTS in a real airport scenario, which is expected to be one of the most UMTS relevant business environments, by means of reusing the existing GSM network infrastructure. In this framework, the paper considers that outdoor macrocells and in-building microcells provide coverage to the area of interest through co-siting 3G sites in existing 2G sites. Different deployment solutions are analysed in terms of number of microcells and maximum power per microcell. The study identifies the suitable configurations and parameters depending on the considered service mix and taking into account both technical and economical issues.