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Event Generation Engine

The EGE may be seen as the main clock of the Monte-Carlo snapshots taking place inside SEAMCAT. As such it provides the main stage for simulation of non-CDMA / non-OFDMA systems, but it also provides the general simulations management even if CDMA / OFDMA systems are defined in the simulation scenario, by invoking the CDMA or OFDMA functions, power control module etc at relevant instances.

The EGE starts when you initiates simulation by pressing the '''Start simulation''' button, after creating the relevant simulations workspace with the considered interference scenario. For each snapshot, the EGE generates random values for the scenario parameters (such as transmitter power, operating frequency, etc) using the distributions defined in scenario, and then processes them to calculate:

  • the desired Received Signal Strength (dRSS), which is the strength of the desired signal received at the Victim Link Receiver (VLR) from the Victim Link Transmitter (VLT), and
  • the interfering Received Signal Strength (iRSS), which is the strength of a signal from the Interfering Link Transmitter (ILT) received at the VLR.

The Interfering Link transmitter has a peer Interfering Link Receiver (ILR) and the signal from ILT to ILR may be also calculated by the program, e.g. for triggering the Power Control function at the ILT. But this vector is not available for postprocessing.

This process is repeated inside the EGE N times, where N is the number of events, specified in the scenario control settings. The generated samples of the desired and all interfering signals are stored in separate data arrays of length N.

For generic systems, there are three major interference mechanisms considered by SEAMCAT, hence three different iRSS vectors are generated for each respective type of interfering signal:

  • unwanted interference - iRSSunwanted signal vector - the unwanted emissions of IT falling in the receive bandwidth of VR,
  • blocking interference - iRSSblocking signal vector - the total emission power of IT reduced by the blocking attenuation (selectivity) function of VR,
  • intermodulation interference - iRSSintermod signal vectors - the power of intermodulation products, reduced by the intermodulation attenuation function of VR.

More than one interfering system can be considered in SEAMCAT scenario. For example, for calculation of intermodulation at least two different systems have to be defined in the workspace scenario.

The EGE algorithm follows the main steps:

  • Initialisation, used to calculate following values that will remain constant for the entire scope of the simulation:
  • Then the different signals are calculated sample-per-sample in following order:

Note: In cases when there is a CDMA / OFDMA system defined in the scenario, the EGE invokes the CDMA / OFDMA Engine at relevant points. For instance, if the interfering system is a CDMA, the EGE will invoke the CDMA engine before the calculation of the iRSS signals, and when the CDMA engine completes the power balancing of the CDMA system, it will return to EGE with a list of relevant transmitters of CDMA system (e.g. list of all mobile stations inside reference cell for CDMA uplink), which will be then used by the EGE as interfering transmitters in final stages of calculating the iRSS signals.