Basic Call Processing - Typical Packet Call                  Home : www.sharetechnote.com

 

 

Now the next step is to describe each of the steps in as much detail as possible. The more in detail you can describe, the easier the development, testing, troubleshooting will be. There are many steps I couldn't describe here because the most of steps not described here would be related to company confidentials (Of course, you can say "Every details are in 3GPP specification".Yes, that's true, but 3GPP says only about "What to do", it doesn't say much about "How to do". In real implementation, this "How to do" part is as important as "What to do") You can take this as a minimum of possible-detailed description. Going through this table, think about how much additional comments you think you can put in 'Memo' column. (If you want to see what's really happening in real network, see the live air example in Full Stack page and Call Processing in Detail with Amarisoft page)

 

NOTE : Following sequence is based on the sequence that would be seen in eNB. Of course, you should see the same sequence on UE side except that UE should have its counter part sequence to < NW >. Some people may think I am writing this table just to confuse people :), but this table is what I have been most often for protocol troubleshooting.

Step

Direction

Message

Memo
1 UE <--- SS MIB  
2 UE <--- SS SIB1  
3 UE <--- SS SIB2,3 and others  
4 UE ---> SS

PRACH (RACH Preamble)-Msg1

  
5

< NW >

 PHY_PRACH_IND  
6

< NW >

 MAC_DATA_IND  
7 UE <--- SS

RACH Response - Msg2

  
8

< NW >

 MAC_DATA_REQ  
9

< NW >

 PHY_PRACH_REQ  
10 UE <--- SS DCI 1A To decode RAR in UE
11

< NW >

 PHY_PRACH_IND  
12

< NW >

 MAC_DATA_IND  
13

< NW >

 RLC_DATA_IND  
14 UE ---> SS

RRC Connection Request - Msg3

  
15

< UE >

UE MAC start mac-ContentionResolutionTimer

3GPP 36.321 5.1.5

CR Timer value is set in SIB2
16 UE <--- SS ACK (PHICH)

 
17 UE <--- SS Contention Resolution - Msg4 SS must send CR before CRtimer get expired
18

< UE >

UE MAC stop mac-ContentionResolutionTimer

  
19

< NW >

 MAC_DATA_REQ  
20

< NW >

 PHY_PRACH_REQ  
21 UE <--- SS DCI 1A To decode CR in UE
22 UE <--- SS

RRC Connection Setup

 In some case, this message gets piggybacked to step 8.
23

< NW >

 RLC_DATA_REQ  
24

< NW >

 MAC_DATA_REQ  
25

< NW >

 PHY_DATA_REQ  
26 UE <--- SS DCI 1A To decode RRC Conn Setup
27 UE ---> SS HARQ ACK  
28 UE ---> SS Scheduling Request To send RLC ACK from UE
29 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
30

< NW >

 PHY_DATA_REQ  
31

< NW >

 MAC_DATA_REQ  
32 UE ---> SS RLC ACK  
33 UE <--- SS HARQ ACK (PHICH)

 
34 UE ---> SS Scheduling Request To send RRC Conn Setup Complete from UE
35 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RRC Conn Setup Complete from UE
36

< NW >

 PHY_DATA_IND  
37

< NW >

 MAC_DATA_IND  
38

< NW >

 RLC_DATA_IND  
39

< NW >

 PDCP_DATA_IND  
40 UE ---> SS

RRC Connection Setup Complete

+ Attach Requeset

+ (PDN Conn Request)

  
41 UE <--- SS HARQ ACK (PHICH)

 
42 UE <--- SS RLC ACK  
43

< NW >

 MAC_DATA_REQ  
44

< NW >

 PHY_DATA_REQ  
45 UE <--- SS DCI 1A To decode RLC ACK in UE
46 UE <--- SS

Authentication Request

  
47

< NW >

 PDCP_DATA_REQ  
48

< NW >

 RLC_DATA_REQ  
49

< NW >

 MAC_DATA_REQ  
50

< NW >

 PHY_DATA_REQ  
51 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To decode Authentication Request in UE
52 UE ---> SS HARQ ACK  
53 UE ---> SS Scheduling Request To send RLC ACK from UE
54 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
55 UE ---> SS RLC ACK  
56 UE <--- SS HARQ ACK (PHICH)

 
57

< NW >

 PHY_DATA_REQ  
58

< NW >

 MAC_DATA_REQ  
59 UE ---> SS Scheduling Request  
60 UE <--- SS

DCI 0 (UL Grant, PDCCH)

  
61

< NW >

 PHY_DATA_IND  
62

< NW >

 MAC_DATA_IND  
63

< NW >

 RLC_DATA_IND  
64

< NW >

 PDCP_DATA_IND  
65 UE ---> SS

Authentication Response

  
66 UE <--- SS HARQ ACK (PHICH)

 
67 UE <--- SS RLC ACK  
68

< NW >

 MAC_DATA_REQ  
69

< NW >

 PHY_DATA_REQ  
70 UE <--- SS

DCI 1A 

 To decode RLC ACK in UE
71 UE <--- SS

NAS Security Mode Command

  
72

< NW >

 PDCP_DATA_REQ  
73

< NW >

 RLC_DATA_REQ  
74

< NW >

 MAC_DATA_REQ  
75

< NW >

 PHY_DATA_REQ  
76 UE <--- SS DCI 1A To decode NAS Security Mode Command in UE
77 UE ---> SS HARQ ACK  
78 UE ---> SS Scheduling Request(PUCCH) To send RLC ACK from UE
79 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
80

< NW >

 PHY_DATA_IND  
81

< NW >

 MAC_DATA_IND  
82 UE ---> SS RLC ACK  
83 UE <--- SS HARQ ACK (PHICH)

 
84 UE ---> SS Scheduling Request(PUCCH) To Send NAS Security Mode Complete
85 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To Send NAS Security Mode Complete
86

< NW >

 PHY_DATA_IND  
87

< NW >

 MAC_DATA_IND  
88

< NW >

 RLC_DATA_IND  
89

< NW >

 PDCP_DATA_IND  
90 UE ---> SS

NAS Security Mode  Complete

  
91 UE <--- SS HARQ ACK (PHICH)

 
92 UE <--- SS RLC ACK  
93

< NW >

 MAC_DATA_REQ  
94

< NW >

 PHY_DATA_REQ  
95 UE <--- SS DCI 1A To decode RLC ACK in UE
96 UE <--- SS

RRC Security Mode Command

  
97

< NW >

 PDCP_DATA_REQ  
98

< NW >

 RLC_DATA_REQ  
99

< NW >

 MAC_DATA_REQ  
100

< NW >

 PHY_DATA_REQ  
101 UE <--- SS DCI 1A To decode RRC Security Mode Command in UE
102 UE ---> SS HARQ ACK  
103 UE ---> SS Scheduling Request To send RLC ACK from UE
104 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
105

< NW >

 PHY_DATA_IND  
106

< NW >

 MAC_DATA_IND  
107 UE ---> SS RLC ACK  
108 UE <--- SS HARQ ACK (PHICH)

 
109 UE ---> SS Scheduling Request To send RRC Security Mode Complete from UE
110 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RRC Security Mode Complete from UE
111

< NW >

 PHY_DATA_IND  
112

< NW >

 MAC_DATA_IND  
113

< NW >

 RLC_DATA_IND  
114

< NW >

 PDCP_DATA_IND  
115 UE ---> SS

RRC Security Mode Complete

  
116 UE <--- SS HARQ ACK (PHICH)

 
117 UE <--- SS RLC ACK  
118

< NW >

 MAC_DATA_REQ  
119

< NW >

 PHY_DATA_REQ  
120 UE <--- SS DCI 1A To decode RLC ACK in UE
121   < Many other message can be added here depending on NW >  

122

 UE <--- SS

RRC Connection Reconfiguration

+ Attach Accept

+ Activate Default EPS Bearer Context Request

 
123

< NW >

 PDCP_DATA_REQ  
124

< NW >

 RLC_DATA_REQ  
125

< NW >

 MAC_DATA_REQ  
126

< NW >

 PHY_DATA_REQ  
127 UE ---> SS HARQ ACK  
128 UE ---> SS Scheduling Request(PUCCH) To send RLC ACK from UE
129 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
130

< NW >

 PHY_DATA_IND  
131

< NW >

 MAC_DATA_IND  
132 UE ---> SS RLC ACK  
133 UE ---> SS Scheduling Request(PUCCH) To send RRC Connection Reconfig Complete from UE
134 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RRC Connection Reconfig Complete from UE
135

< NW >

 PHY_DATA_IND  
136

< NW >

 MAC_DATA_IND  
137

< NW >

 RLC_DATA_IND  
138

< NW >

 PDCP_DATA_IND  
139 UE ---> SS

RRC Connection Reconfiguration Complete

+ Attach Complete

+ Activate Default EPS Bearer Context Accept

  
140 UE <--- SS HARQ ACK (PHICH)

 
141 UE <--- SS RLC ACK  
142

< NW >

 MAC_DATA_REQ  
143

< NW >

 PHY_DATA_REQ  
144 UE <--- SS DCI 1A To decode RLC ACK in UE
145   < IP Data Traffic if needed >  
146 UE <--- SS RRC Connection Release  
147

< NW >

 PDCP_DATA_REQ  
148

< NW >

 RLC_DATA_REQ  
149

< NW >

 MAC_DATA_REQ  
150

< NW >

 PHY_DATA_REQ  
151 UE <--- SS DCI 1A To decode RRC Connection Release in UE
152 UE ---> SS HARQ ACK  
153 UE ---> SS Scheduling Request(PUCCH) To send RLC ACK from UE
154 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
155

< NW >

 PHY_DATA_IND  
156

< NW >

 MAC_DATA_IND  
157 UE ---> SS RLC ACK  
158 UE <--- SS HARQ ACK (PHICH)

 
159 UE < Now UE should be in IDLE mode >