How to set periodic or aperiodic packet

How to set periodic or aperiodic packet

1 Introduction

In WiLabV2Xsim, the packet generation interval is a summation of two parts, which are "Deterministic Part (DP)" and "Random Part (RP)". The DP would be initialized at the beginning of the simulation and would not change anymore during the simulation. While the RP would be changed each time the packet was generated.

Some data traffic models could be found in 3GPP TR 37.885 V15.3.0 (2019-06)

2 Parameters

The parameters mentioned in this section could be passed into the simulator through config file or as arguments, please see 2.2 Parameters

2.1 Unit and default values of parameters

Parameter	Unit	Default value
generationInterval	second	==allocationPeriod (0.1)
variabilityGenerationInterval	second	0
generationIntervalAverageRandomPart	second	0
vMean	km/h	114.23
vStDev	hm/h	12.65

2.2 The Finial Packet Generation Interval

The finial packet generation interval (FGI) would be expressed as:

FGI = DP + RP

2.3 Deterministic Part related

• variabilityGenerationInterval
  • If set as -1 and simParams.typeOfScenario~=2
    • DP would be related to vMean and vStDev
  • Else
    • For IEEE 802.11p:

    DP = generationInterval - variabilityGenerationInterval/2 + variabilityGenerationInterval*random()

    • For LTE or NR

    DP = generationInterval

2.4 Random Part related

• generationIntervalAverageRandomPart

A random number from exponential distribution with average value generationIntervalAverageRandomPart:

RP = exprnd(generationIntervalAverageRandomPart)

3 Settings

3.1 Note

If the parameter generationInterval is not set by users, its default value is equal to the parameter allocationPeriod (known as RRI, Resource Reservation Interval).

3.2 Periodic

1. All vehicles have same generation interval

• generationInterval=0.1;
• variabilityGenerationInterval=0;
• generationIntervalAverageRandomPart=0

2. All vehicles have different generation interval

• generationInterval=0.2;
• variabilityGenerationInterval=0.1;
  • Note: With this settings, this parameter for LTE or NR vehicle would be treated as 0
• generationIntervalAverageRandomPart=0

3. Vehicles' generation interval related to speed

• variabilityGenerationInterval=-1;
• Leave others as default

3.3 Aperiodic

1. All vehicles generate packet aperiodiclly, same DP

• generationInterval=0.1;
• variabilityGenerationInterval=0;
• generationIntervalAverageRandomPart=0.1

2. All vehicles generate packet aperiodiclly, different DP (only for IEEE 802.11p)

• generationInterval=0.2;
• variabilityGenerationInterval=0.1;
  • Note: With this settings, this parameter for LTE or NR vehicle would be treated as 0
• generationIntervalAverageRandomPart=0.1