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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 systems, but it also provides the general simulations management even if CDMA systems are defined in the simulation scenario, by invoking the CDMA functions and power control module at relevant instances.

The EGE starts when the user initiates simulation by pressing the Start simulation button, after having created 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 Receiver (VR) from the Wanted Transmitter (WT), and
• the interfering Received Signal Strength (iRSS), which is the strength of a signal from the Interfering Transmitter (IT) received at the VR.

Interfering transmitter has a peer Wanted Receiver (WR) and the signal from IT to WR may be also calculated by the program, e.g. for triggering the Power Control function at the IT.

This process is repeated inside EGE for N times, where N is the number of trials/snapshots, specified by the user in scenario control settings. Generated samples of the desired and all interfering signals are stored in separate data arrays of length N.

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.

EGE algorithm is comprised of following main steps:

• Initialisation, used to calculate following values that will remain constant for the entire scope of the simulation:

• Coverage radius of the wanted transmitter
• Coverage radius of each interfering transmitter
• Simulation radius of each interfering transmitter if uniform density mode selected
• Then the different signals are calculated sample-per-sample in following order:
  • dRSS calculation
  • iRSS blocking and unwanted calculation (common algorithm)
  • iRSS intermod calculation

Note: In cases when there is a CDMA system defined in the scenario, the EGE invokes the CDMA Engine (CDMAE) at relevant points. E.g. if interfering system is a CDMA, the EGE will invoke CDMAE before calculation of iRSS signals, and after CDMAE completes power balancing in CDMA system, it will return to EGE the 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 EGE as interfering transmitters in final stages of calculating iRSS signals.