12 Results

• 12.1 Scenario outline
• 12.1.1 Simulation Summary
• 12.1.2 Simulation status
• 12.1.3 Generic system outline
• 12.1.4 Cellular system outline
• 12.2 Overview of output results
• 12.3 Generic model Results
• Introduction
• 12.3.1 Generated signals results
• 12.3.2 Calculated radius
• 12.3.3 Intermodulation results
• 12.3.4 Overloading results
• 12.4 Spectrum sensing results
• Introduction
• 12.4.1 sRSS vector
• 12.4.2 WSD frequency
• 12.4.3 WSD e.i.r.p.
• 12.4.4 Victim frequency vector
• 12.4.5 Average e.i.r.p. per frequency
• 12.4.6 Average active WSDs per frequency vector
• 12.5 CDMA output results
• 12.5.1 CDMA capacity finding
• 12.5.2 CDMA results
• 12.5.3 CDMA results for cell selection algorithm
• 12.6 OFDMA output results
• 12.7 EPP results
• 12.8 Cellular Structure
• Introduction
• 12.8.1 Plot configuration
• 12.8.2 Summary of event #n
• 12.8.3 Inspect selected element
• 12.9 Interference calculations
• 12.9.1 Introduction
• 12.9.2 Interference calculation GUI
• 12.9.3 Interference Calculation Engine Control

12.1 Scenario outline

12.1.1 Simulation Summary

The simulation summary (left of Figure 242) provides a quick access to the mean, median and standard deviation of the dRSS, iRSS unwanted and iRSSblocking

The mean is computed using the simulated results in dB. The median is computed using the simulated results converted to linear values and then converted again to dB. The standard deviation (StdDev) is computed using the simulated results in dB. This is further explained in Annex A1.5.1.

12.1.2 Simulation status

The progress bar (right of Figure 242) reflects the percentage of events simulated with respect to overall number of events specified in the simulation control window in the scenario tab.

 

12.1.3 Generic system outline

During the event generation all involved transceivers (ILT, ILR, VLR and VLT) are plotted in graphical display window placed on the simulation outline tab. 

 

 

 

The dRSS and the iRSS vectors are shown for 100 events maximum to avoid overloading the memory and to speed the computation time. The iRSS is shown as a summation of all the interferers.

12.1.4 Cellular system outline

Once SEAMCAT has determined the number of UEs per cell either through simulation of optimal capacity (see Figure 197 for UL and Figure 198 for DL or by a value that you specify the actual simulation of snapshots begins. As with all scenarios this causes SEAMCAT to show the scenario outline (Figure 245 for UL and Figure 246 for DL). 

 

 

 

 

Only CDMA base-stations will appear in the Scenario outline graph. Dependent on the scenario the base-stations positioning will appear as shown in Table 50.

 

 

 

 

12.2 Overview of output results

 

12.3 Generic model Results

Introduction

After running a simulation with generic system, each of these signals is displayed with indicated array size (i.e. the number of valid generated events), unit and then the type (vector, double etc..).

Double-clicking on one of the vectors, the signal dialog window (see Annex A1.5) will plot the signal as well as its statistical features. 

 

12.3.1 Generated signals results

• dRSS folder (‎ANNEX 4:) with dRSS vector;

• iRSS unwanted folder (‎ANNEX 5:) with as many iRSSunwanted vector for each interfering link and one vector for the sum;

• iRSS blocking folder (‎ANNEX 5:) with as many iRSSblocking vector for each interfering link and one vector for the sum.

12.3.2 Calculated radius

The calculated radius folder contains the values of the coverage and/or simulation radii calculated for the event generation when set to non-correlated (See ANNEX 13:). 

12.3.3 Intermodulation results

iRSS intermodulation folder (Figure 248) with as many iRSSintermod vector for each combinatory couple in case there are more than one interfering link and one vector for the sum.

Figure 248: Intermodulation results folder

 

12.3.4 Overloading results

As a result of the equation described in Annex A5.4, for each event and at each frequency, the sum of the iRSS_overloading (iRSS_{sum_overloading}) will be compared to the overloading treshold O^th(f_i) at that frequency (f_i). The difference, delta (in dB), will be stored.

• When delta ≥ 0, then the receiver is overloaded at that f_i (i.e. the rest of the frequency do not matter);

• When delta < 0, then the receiver is not overloaded at f_i.

If only one frequency is present, the iRSS_{sum_overloading} is compared to the O^th(f_i)and the difference will be stored for that event.  If more than one frequency is present, the highest delta value will be indicated in the vector (i.e. irrespective of the frequency) such that 

for each event j (where dRSS > sensitivity){

for Frequency = i to number of total frequencies{ delta_max(j) = max(delta(f_i)); }                             (Eq. 67)

}

 

The output delta overloading vector is of the dimension delta x number of events

 

12.4 Spectrum sensing results

Introduction

When the cognitive radio mode is activated, SEAMCAT resturns the output vector shown in Figure 251 and described in Table 52.

 

 

 

At the end of the simulation, SEAMCAT provides a set of output vectors as above. Then you can perform the interference probability calculation as previously described.

12.4.1 sRSS vector

The sRSS vector (dBm) is merely the sRSS value calculated at the selected WSD frequency (i.e. where the WSD is allowed to transmit) for each of the event. Figure 252 displays the vector for each WSD. You can select any or all of the WSD (#1). The same applies to the CDF and density graphs (#2).

 

 

You are able to save the results (#4) as .txt file for further post-processing.

 

12.4.2 WSD frequency

This vector represents the actual selected frequency (MHz) at which the WSDs are allowed to transmit as the result of the spectrum sensing algorithm.

 

 

 

12.4.3 WSD e.i.r.p.

The actual selected e.i.r.p. (dBm) at which the WSDs are allowed to transmit as the result of the spectrum sensing algorithm. This vector displays the e.i.r.p. for each of the WSD for all the events. In the example presented in Figure 256, the WSDs are transmitting with a e.i.r.p. between -10 and 20 dBm and -1000 dBm (equivalent to WSD switch off).

 

12.4.4 Victim frequency vector

The victim frequency vector (MHz) represents the frequency at which the victim device transmits per event. 

12.4.5 Average e.i.r.p. per frequency

It presents the average e.i.r.p. per event (dBm vs MHz) for all the active WSDs transmitting at a certain frequency such that:

 

    (Eq. 68)

 

Let us assume a different example from above, where 4 channels have been identified for the WSD to operate. Figure 257 shows that on average 33 dBm, for one event, was transmitted by the active WSDs at 1000.5 MHz , 8.82 dBm at 1001.5 MHz etc...

 

12.4.6 Average active WSDs per frequency vector

It provides the average number of active WSD per event for a specific frequency:

                                        

   (Eq. 69)

Re-using the example of Figure 257, Figure 258 indicates that, with for instance 5 WSDs set as input parameters, an average of 0.63 WSDs were active at 1000.5 MHz (with 33 dBm e.i.r.p. Figure 257), 1.29 WSDs were active at 1001.5 MHz (with 8.82 dBm e.i.r.p. Figure 257), 1.57 active WSDs at 1002.5 MHz and 1.51 active WSDs at 1003.5 MHz. It can also be noted that in this particular example, the sum of the active WSDs across the selected frequencies is 5, meaning that all the simulated WSDs have been active and none have been turn off.

 

12.5 CDMA output results

12.5.1 CDMA capacity finding

During the pre-simulation part, the system estimates the load of the network as shown in Figure 259. The results are presented as in Figure 260.

 

 

 

12.5.2 CDMA results

Once SEAMCAT has completed the simulation, the results are shown as displayed in Figure 261, when the CDMA network is the victim. This figure presents the difference between the 2 steps power balancing process (1-initial power balancing, 2- power balancing after introduction of an external interference), that is to say " non-interfered capacity " is the number of UEs in the victim network prior to adding an external interferer and "interfered capacity" is the number of UE in the victim network after adding the external interference.

• Units: number of connected UEs;

• Initial capacity: Number of connected UEs before any external interference is considered;

• Interfered capacity: Results after External interference is applied;

• Excess outage, users: How many UEs were dropped due to external interference;

• Outage percentage: Percentage of UEs dropped due to external interference.

When the CDMA system is the interfering link, the total received power at the receiver in the victim link, due to the transmit power of all the active mobile stations in the three cells of the center cell site of the CDMA cluster, adjusted for spectral masks, etc., is counted as the interfering power in the victim link.  Therefore, it is not necessary to keep track of any capacity loss in this case, unless the victim link is also a CDMA system.

 

 

 

 

SEAMCAT is able to calculate (for CDMA) 3 losses:

1)     Loss of UEs for the whole network based on the before and after number of UE

 

System capacity loss = 100 - (interfered_capacity/ non-interfered_capacity)*100              (Eq. 70)

 

2)     Loss of UEs for the reference cell based on the before and after number of UE

Ref cell capacity loss = 100 - (interfered_capacity/ non-interfered_capacity)*100              (Eq. 71)

 

3)     Loss of UEs for the whole network based on the total number of dropped UE

System capacity loss = total_dropped_UE_system/total_simulated_UE*100                    (Eq. 72)

 

It is quite important to understand that there is not a 1-to-1 map between non-interfered active/interfered users and the dropped users. Dropped user can occurs at many level of the algorithm, it can be due to:

• “Unable to connect during first initialisation of UE” during the initialization (long before the step 2 balancing) but still it will be registered;

• During the balancing. For CDMA UL (no cell selection activated), when the noise rise is balanced, i.e. the number of UE is acceptable is reached after introduction of external interferers,  then the BS estimates the signal-to-interference ratio (C/I), measured in bit energy-to-noise density ratio Eb/N0, and compares it to a target value (Eb/N0_target). If the difference between the estimated C/I and the Eb/N0_target, is higher than a call drop threshold, then the UE is dropped;

• “Eb/No requirement does not meet while scaling the channel power” during the scaling power.

12.5.3 CDMA results for cell selection algorithm

When the CDMA “cell selection” algorithm is simulated, the following output vectors are also available for scrutiny:

12.6 OFDMA output results

The results of the OFDMA simulation are given in terms throughput loss of the OFDMA victim. Figure 263 presents an overview of the simulation results. It consists of the achieved bitrate (with or without external interference) for the reference cell or the whole system.

A summary of the bit rate loss expressed in percentage for both the reference cell and the entire OFDMA network (i.e. the whole system) is also available. The percentage calculation is performed for each snapshot and the mean of the percentage over all the snaphsots is deduced.

 

12.7 EPP results

In case an EPP is used and it returns a set of result, they will also be included next to the statistic panel as shown in  Figure 264. The EPP can also produce results like Single values, Vectors, Vector groups, Scatter diagrams, Barcharts.

 

12.8 Cellular Structure

Introduction

When simulating CDMA or OFDMA systems, you will have access to the additional tab "Cellular structure", which will become active after completion of the simulation. This new tab allows you to inspect the internal details of CDMA/OFDMA cluster based on data on one event.

After a simulation these GUI parts are used to provide access to calculated results but also detailed insight into the last event of the simulation as illustrated in Figure 265, but you can reproduce any event using the play/replay feature (Section ‎2.15).

The “Summary of event #n” and “inspect selected element” panel of Figure 265 are shared components from the CDMA and OFDMA module. 

 

12.8.1 Plot configuration

The top part of the detailed system information screen contains a range of checkboxes used to control which information is plotted (Figure 266).  A full description of each checkbox is given in Table 53.

 

 

 

The main part of the CDMA network Details window is used by the main plot. The plot shows a visual representation of the last snapshot and should be used to validate that the input parameters actually corresponds to the system that should be simulated. The plot allows for heavy user interaction. A very basic example is shown Figure 267 below.

Figure 267: Main plot of CDMA network 

 

12.8.2 Summary of event #n

The “Summary of event#n” panel provide a few metrics on the number of users simulated Figure 268

 

 Table 54: Snapshot summary description

12.8.3 Inspect selected element

12.9 Interference calculations

12.9.1 Introduction

The Interference Calculation Engine (ICE) is that part of the SEAMCAT architecture which calculates for generic victim receiver the probability of being impacted by the sum of the simulated interference power. The calculated result is commonly called "Interference probability" or " probability of interference", in fact it is the probability of exceeding the limit of one of the interference criteria given for the victim receiver.

Regarding the definition of the Radio Regulations (RR) Article 1.166

The effect of unwanted energy due to one or a combination of emissions, radiations, or inductions upon reception in a radiocommunication system, manifested by any performance degradation, misinterpretation, or loss of information which could be extracted in the absence of such unwanted energy.

 

Administrations may have to distinguish between permissible interference (RR 1.167) and accepted interference (RR 1.168).

Details of the interference calculation algorithm are given in ‎ANNEX 2:.

12.9.2 Interference calculation GUI

When the simulation is finished, the dRSS and the iRSS vectors are stored. You may proceed to use the facilities of the Interference Calculation Engine (ICE) in order to evaluate the probability of interference for the simulated scenario.

The probability of interference is calculated by the ICE with the following choice of input parameters:

 

If more than one interference calculation was done (i.e. with different combination of interference criterion), you may scroll through all of them by using the Previous / Next buttons.

Interference calculation results:

 

When the compatiblity mode is chosen, a single-figure estimate of the probability of interference is calculated;

 

When the Translation mode is chosen, you may calculate and display as chart the probability of interference as function of one of the following input parameters:

 

You are able to save the results of the translation mode using the “save translation button”.

 

 

 

 

 

12.9.3 Interference Calculation Engine Control

 It allows to the calculation of the probability of interference for several ICE configurations (i.e. different signal types, interference criteria, etc..) for the same simulation. Figure 272 presents how the control box is used.

When the translation mode is activated, the overloading feature is deactivated as shown in Figure 273.