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In this section the interference calculations for ‘generic’ systems are described. Cellular systems (OFDMA and CDMA) use a different interference calculation method based on throughput and capacity loss which are described in more detail in ANNEX 15:

The C/I ratio available at the victim receiver’s input is computed using both the iRSS (Interfering Received Signal Strength) and the dRSS (desired Received Signal Strength),. Figure 7 illustrates the various signal levels used to determine whether or not inte...

Four interference criteria are considered within SEAMCAT: C/I         : Carrier to interference ratio; C/(I+N)   : Carrier to interference plus noise ratio; (N+I)/N   : Desensitisation; I/N         : Interference to noise ratio.   All of these criter...

C/I may vary typically from 9 dB (e.g. for QPSK) to 26 dB or higher (e.g. for 64QAM…). By introducing artificial noise iRSS on top of the noise floor (I/N), C/I is then desensitised by (N+I)/N resulting in C/(N+I). Note that the desensitisation is exactly the ...

The level of unwanted emissions  ( i.e. consisting of the out-of-band emissions and the spurious emissions [8] of the ILT) falling within the VLR receiver bandwidth (Figure 11) is determined using the interferer’s transmit mask, the receiver bandwidth of the V...

The level of interference determined by the interferer’s transmit power, the antenna gains and propagation loss, is further decreased due to the receiver blocking performance for a given interferer/victim frequency separation. Details on the iRSSblocking calcu...

The intermodulation interference, i.e. the power of intermodulation products, reduced by the intermodulation attenuation function of the VLR can be used in interference calculations. See ANNEX 5: for further details.

Overloading threshold is the minimum interfering signal levelat which the receiver loses its ability to discriminate against interfering signals at frequencies other than that of the wanted signal. See Annex A2.2 for the use of overloading in interference calc...

The combination of the unwanted emissions and receiver blocking can also be studied simultaneously in SEAMCAT as depicted in Figure 13. See Annex A2.3 for further details. Figure 13: Illustration of the combined unwanted emissions and the receiver blocking me...

SEAMCAT calculates the probability of interference for generic (i.e. non-cellular) victim systems. Each sample of dRSS and iRSS generated during a simulation is compared against the relevant signal-to-noise criterion (specified in the scenario, such as C/N, C/...

SEAMCAT can address virtually all radio interference scenarios on terrestrial[1] paths in both co-channel (sharing) and adjacent frequency (compatibility) interference studies. This flexibility is achieved by the way the system parameters are defined as variab...

Many common terms in RF engineering are used differently depending on the specific community where they are used. The following gives a non-exhaustive example of the variety of terms that can be found. C (i.e. the wanted signal level) is referred to in differe...

SEAMCAT is an open source project developed using Java which means it can run on any operating system supported by Java. The SEAMCAT installation is started by clicking on the install link from www.seamcat.org and it is free of charge. The .jar package is plat...

When SEAMCAT (5 and upward) is run, a folder (SEAMCAT home directory) will be automatically created so that every time a new version of SEAMCAT is run, a subfolder with the version number will be created as shown in Figure 14.  Figure 14: Illustration of the s...

 The source code for SEAMCAT is made available for scrutiny. The only condition for obtaining a copy of the source code is to sign a special Source Code User Licence Agreement and deliver it to ECO by email (seamcat@eco.cept.org). The procedure is described at...

As of version 5, SEAMCAT is able to run in multiprocessor environments to increase the computation speed. The more processors a computer has, the less time a simulation will take. Since the Monte Carlo simulation method considers that each event is independent...

The SEAMCAT project is an ongoing WG SE (Working Group Spectrum Engineering) activity (Figure 16). The daily maintenance of the project and the SEAMCAT software is entrusted to the ECO. The project is funded by the signatories of the ECO council. The SEAMCAT T...

SEAMCAT allows building customized library of components (systems, antennas etc.) or use those created by someone else. It is possible to use predefined antenna patterns, spectrum emission masks, and propagation models etc. which are available in the SEAMCAT l...