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delay-jitter-estimation.cc
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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