1 

     2 #include "delay-jitter-estimation.h"

     3 #include "ns3/tag.h"

     4 #include "ns3/simulator.h"

     5 #include "ns3/string.h"

     6 

     7 namespace ns3 {

     8 

     9 class DelayJitterEstimationTimestampTag : public Tag

    10 {

    11 public:

    12   DelayJitterEstimationTimestampTag ();

    13   static TypeId GetTypeId (void);

    14   virtual TypeId GetInstanceTypeId (void) const;

    15 

    16   virtual uint32_t GetSerializedSize (void) const;

    17   virtual void Serialize (TagBuffer i) const;

    18   virtual void Deserialize (TagBuffer i);

    19   virtual void Print (std::ostream &os) const;

    20 

    21   Time GetTxTime (void) const;

    22 private:

    23   uint64_t m_creationTime;

    24 };

    25 

    26 DelayJitterEstimationTimestampTag::DelayJitterEstimationTimestampTag ()

    27   : m_creationTime (Simulator::Now ().GetTimeStep ())

    28 {

    29 }

    30 

    31 TypeId

    32 DelayJitterEstimationTimestampTag::GetTypeId (void)

    33 {

    34   static TypeId tid = TypeId ("anon::DelayJitterEstimationTimestampTag")

    35     .SetParent<Tag> ()

    36     .AddConstructor<DelayJitterEstimationTimestampTag> ()

    37     .AddAttribute ("CreationTime",

    38                    "The time at which the timestamp was created",

    39                    StringValue ("0.0s"),

    40                    MakeTimeAccessor (&DelayJitterEstimationTimestampTag::GetTxTime),

    41                    MakeTimeChecker ())

    42   ;

    43   return tid;

    44 }

    45 TypeId

    46 DelayJitterEstimationTimestampTag::GetInstanceTypeId (void) const

    47 {

    48   return GetTypeId ();

    49 }

    50 

    51 uint32_t

    52 DelayJitterEstimationTimestampTag::GetSerializedSize (void) const

    53 {

    54   return 8;

    55 }

    56 void

    57 DelayJitterEstimationTimestampTag::Serialize (TagBuffer i) const

    58 {

    59   i.WriteU64 (m_creationTime);

    60 }

    61 void

    62 DelayJitterEstimationTimestampTag::Deserialize (TagBuffer i)

    63 {

    64   m_creationTime = i.ReadU64 ();

    65 }

    66 void

    67 DelayJitterEstimationTimestampTag::Print (std::ostream &os) const

    68 {

    69   os << "CreationTime=" << m_creationTime;

    70 }

    71 Time

    72 DelayJitterEstimationTimestampTag::GetTxTime (void) const

    73 {

    74   return TimeStep (m_creationTime);

    75 }

    76 

    77 DelayJitterEstimation::DelayJitterEstimation ()

    78   : m_previousRx (Simulator::Now ()),

    79     m_previousRxTx (Simulator::Now ()),

    80     m_jitter (0),

    81     m_delay (Seconds (0.0))

    82 {

    83 }

    84 void

    85 DelayJitterEstimation::PrepareTx (Ptr<const Packet> packet)

    86 {

    87   DelayJitterEstimationTimestampTag tag;

    88   packet->AddByteTag (tag);

    89 }

    90 void

    91 DelayJitterEstimation::RecordRx (Ptr<const Packet> packet)

    92 {

    93   DelayJitterEstimationTimestampTag tag;

    94   bool found;

    95   found = packet->FindFirstMatchingByteTag (tag);

    96   if (!found)

    97     {

    98       return;

    99     }

   100   tag.GetTxTime ();

   101 

   102   Time delta = (Simulator::Now () - m_previousRx) - (tag.GetTxTime () - m_previousRxTx);

   103   m_jitter += (Abs (delta) - m_jitter) / 16;

   104   m_previousRx = Simulator::Now ();

   105   m_previousRxTx = tag.GetTxTime ();

   106   m_delay = Simulator::Now () - tag.GetTxTime ();

   107 }

   108 

   109 Time 

   110 DelayJitterEstimation::GetLastDelay (void) const

   111 {

   112   return m_delay;

   113 }

   114 uint64_t

   115 DelayJitterEstimation::GetLastJitter (void) const

   116 {

   117   return m_jitter.GetHigh ();

   118 }

   119 

   120 } // namespace ns3