- About this Wiki
- About the STG (SEAMCAT Technical Group)
- About the source code
- Frequently Asked Questions
- How to register on TracTool?
- Tutorial videos
- Known Issues
Main structural elements of SEAMCAT
- SEAMCAT Data types
- Function entry
- Emissions mask
- Random distributions
- Signal vectors
- How to generate a truncated distribution?
Creating SEAMCAT scenario
- Simulation scenario and its programming
- Victim link tab
- Interfering link tab
- Sharing and importing scenarios
Performing a simulation
- Simulation control settings
- Running a simulation (event generation)
- Calculating probability of interference
- Simulation results overview
- Generic system results
- Simulation report
- Logging options and remote server
- Saving results format
- CDMA system tab
- CDMA Link level data
- CDMA simulation algorithm
- CDMA input parameters
- CDMA output results
Cognitive Radio System module
Library of scenario elements
- Library overview
- Antenna elements
- Spectrum emission mask elements
- Receiver blocking mask elements
- Receiver elements
- Transmitter elements
- CDMA Link level data
- CDMA-OFDMA network
- Propagation model plugins
- Post processing plugins
- Guide to propagation models in SEAMCAT
- How to test propagation model?
- ITU-R P.1546 model
- Extended Hata and Hata-SRD models
- Spherical diffraction model
- Free Space Loss model
- User-defined model (Propagation plug-in)
- JTG5-6 propagation plug-in
- SE42 propagation plug-in
- Longley Rice propagation plug-in
- Winner propagation plug-in
- IEEE 802.11 Model C (modified) plug-in
- Wanted signal (dRSS)
- Unwanted and blocking signals (iRSS)
- Overloading (iRSS)
- Intermodulation signal (iRSS)
- CDMA simulation algorithm
- OFDMA simulation algorithm
- Location of VLR with ILT (Simulation Radius)
- Location of VLR and ILR (Coverage radius)
- Azimuths and elevations (IT-VR path)
- Azimuths and elevations (within a link)
- Blocking attenuation (VLR)
- unwanted emissions (ILT)
- Power control gain (ILT)
Release to be tested by STG
How to set blocking attenuation mode and function of victim receiver
It is very important that the victim receiver blocking attenuation mode and the associated blocking function are set appropriately and in co-ordinated manner, since the interpretation of blocking function trial will depend on the chosen attenuation mode.
Please see the annex on the definition of receiver selectivity and blocking attenuation PDF file (137 KB) for detailed guidance.
Calculation of blocking attenuation
Blocking attenuation (also might be referred to as selectivity feature) is a function of the frequency difference between interfering transmitter and victim receiver Δf = fit - fvr. It is introduced to enable the evaluation of ability of victim receiver's filtering/selectivity mechanisms to withstand the interference from the full power of an interfering transmitter that is transmitting in an adjacent channel/band.
Three calculation modes are available, according to the way the Blocking function is defined in the scenario (see section below):
- Blocking function set as User-defined attenuation function, representing the actual receiver filter mask (in dB). In this case the blocking attenuation value is simply derived from the user-defined function depending on the IT-VR frequency shift as an argument;
- Blocking function is defined in Protection ratio mode, corresponding to the required protection ratio (in dB). In this case the blocking attenuation value is derived as follow:
- Blocking function is defined in Sensitivity mode, representing the absolute maximum interfering power tolerated by the victim receiver (in dBm). In this case the blocking attenuation value is derived as follow:
Note that the C/(N+I) value used in the above formulas is taken directly from the interference criteria settings of the Victim Receiver. Therefore users must carefully set this value in the scenario. See further guidance on application of the above formulas with the consistency check.
CDMA / OFDMA simulation: How to simulate multiple ACS due to multiple interferers with various bandwidths?
When simulating cellular environment like LTE, the 3GPP standard provides different ACS values depending on the bandwidth of the interferer. For instance, it is known that LTE can support flexible channel bandwidth, 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz and 20MHz. Therefore, in order to be able to deal with more LTE co-existence scenarios in the future, it is unavoidable to support scenarios with different bandwidth interferers.
SEAMCAT is able to handle such a case. The following provides information on how to do define the workspace in SEAMCAT.
Defining the ACS mask
Let’s assume the following example of two interferers with two distinct bandwidth (10MHz and 5 MHz) which results in 2 ACS values. For this you would need to introduce a ACS “mask” so that it is defined at the specific interference frequencies for various interfering bandwidth and not to a same bandwidth. You need to define the ACS to the left for 10 MHz using the approximation of 3GPP TR36.942 (p75) and you can define the ACS for 5 MHz in the right hand side.
In the case where two interferers are geographically separated but transmitting at the same frequency, you can trick SEAMCAT by slightly shifting one of the frequency (a few kHz is enough) so that the value for a specific frequency is used in the simulation (see below).
The only situation, where it would be difficult (but still feasible) is when the interfering frequency is distributed over a large bandwidth, then you would have to define the “other” ACS value elsewhere in the frequency domain and you may have 1‐2 dB difference due to the propagation models (exact value to be assessed of course).
Calculating the average ACS value
According to 3GPP TR36.942 p75, there are some example calculations of average ACS. For example the following equation:
Which means Average ACS or called equivalence ACS values is equal to the following.
Note: Using this method, each BWN should be the multiple of unit bandwidth in reception mask. For example, in the case of 3GPP TR36.942, ACS1, ACS2 and ACS3are defined in 5MHz band and 30 MHz are the multiples of 5.
- Calculate the ACS values for each of the interfering bandwidth that you want to simulate.
- Set the “mask” in SEAMCAT so that for a specific interfering frequencies you have the appropriate ACS values
- img1.gif (2.0 KB) - added by cp 5 years ago.
- img2.gif (2.0 KB) - added by cp 5 years ago.
- ACS_usage_in_SEAMCAT.pdf (143.1 KB) - added by jean-philippe 21 months ago.
- Blocking_attenuation.pdf (136.6 KB) - added by jean-philippe 10 months ago.
- ACS_eq1.gif (3.9 KB) - added by jean-philippe 9 months ago.
- ACS_eq2.gif (3.6 KB) - added by jean-philippe 9 months ago.
- ACS_fig1.gif (15.7 KB) - added by jean-philippe 9 months ago.
- ACS_fig2.gif (11.7 KB) - added by jean-philippe 9 months ago.
- ACS_fig3.gif (31.3 KB) - added by jean-philippe 9 months ago.