Security Protocol Animator (SPAN) is a free tool to check cryptographic protocols that helps in searching and characterization of attacks. The main advantage of this application is that allows different verification techniques using a same protocol. We can say, it is a graphical interface for managing HLPSL (High-Level Protocol Specification Language) and CAS + (an implementation of the Protocol Central Authentication), which allows the translation between these languages ​​and also provides a friendly graphical user interface. SPAN helps to produce interactively sequences messages or MSC (Message Sequence Charts).

This tool is used for simulating cryptographic protocol, allows active or passive intruder simulation, the automatic attack's construction of the designed protocols. The protocol can be edited by means of HLPSL or CAS+, having the ability to convert between these languages. Some features of the graphical user interface are shown in Figure # 1.

Figure # 1: SPAN GUI description.

Some studies show that over 50% of voice calls and 70% of the data traffic comes from inside [1], voice calls do not require high bandwidth, but certain quality parameters are require to ensure the voice recognition of users at the other end of the communication, on the contrary, the data traffic requires high transmission rates to send information with a lot of megabytes, such as multimedia applications require, to name one example. One way to ensure high transmission rates on radio systems, is to maintain high signal quality at both ends of the communication, and hence, mitigate the effects of loss and interference in the communication channel.

In this context, operators have deployed femto-cells systems in order to decrease the distance to the EU and to maintain good signal quality. However, femto-cells must operate in the designated band frequency for such communication and match to the assigned frequencies to the operator, from this perspective, femto-cell generates interference and it can be given in the following ways [2]:

• Femto-cell to femto-cell.

• Femto-cell to macro-cell

• Macro-cell to femto-cell.

The interference problems between femto-cell is due the coverage that they have, this type of interference will occur primarily within the coverage limits where the femto-cells interact each other, the Figure # 1 shows this phenomenon, in which the FAP 1 and FAP 2 coverage have overlaps producing signal degradation for users of both femto-cells in that area.

Figure # 1. Interference problems between macro/femto cells.

Results presentation

The way in which the research results are presented has a significant impact on readers. Also, a good way to represent the information gives a clear and easy ideas to understand. For this, we need a selection of tools that allow the reproduction of documents, photographs, graphics, and other associated items. On the other hand, there are various applications which facilitate the data processing when we need to work with research result, whether mathematical or network.