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) To confirm Msg3 Reception
17 UE <--- SS DCI 1A or DCI1 To decode CR in UE
18 UE <--- SS Contention Resolution - Msg4 SS must send CR before CRtimer get expired
19 UE ---> SS HARQ ACK To Confirm CR Reception at PHY
20

< UE >

UE MAC stop mac-ContentionResolutionTimer

  
21

< NW >

 MAC_DATA_REQ  
22

< NW >

 PHY_PRACH_REQ  
23 UE <--- SS DCI 1A To decode RRC Conn Setup in UE
24 UE <--- SS

RRC Connection Setup

 In some case, this message gets piggybacked to step 18.
25

< NW >

 RLC_DATA_REQ RLC Carrying step 24
26

< NW >

 MAC_DATA_REQ MAC Carrying step 24
27 UE <--- SS DCI 1A To decode RRC Conn Setup
28

< NW >

 PHY_DATA_REQ PHY Carrying step 24
29 UE ---> SS HARQ ACK Response to step 28
30 UE ---> SS Scheduling Request To send RLC ACK from UE
31 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
32

< NW >

 PHY_DATA_REQ  
33

< NW >

 MAC_DATA_REQ  
34 UE <--- SS HARQ ACK (PHICH)

 
35 UE ---> SS RLC ACK  
36 UE ---> SS Scheduling Request To send RRC Conn Setup Complete from UE
37 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RRC Conn Setup Complete from UE
38

< NW >

 PHY_DATA_IND  
39

< NW >

 MAC_DATA_IND  
40

< NW >

 RLC_DATA_IND  
41

< NW >

 PDCP_DATA_IND  
42 UE ---> SS

RRC Connection Setup Complete

+ Attach Requeset

+ (PDN Conn Request)

  
43 UE <--- SS HARQ ACK (PHICH)

 
44 UE <--- SS RLC ACK  
45

< NW >

 MAC_DATA_REQ  
46

< NW >

 PHY_DATA_REQ  
47 UE <--- SS DCI 1A To decode RLC ACK in UE
48 UE <--- SS

Authentication Request

  
49

< NW >

 PDCP_DATA_REQ  
50

< NW >

 RLC_DATA_REQ  
51

< NW >

 MAC_DATA_REQ  
52

< NW >

 PHY_DATA_REQ  
53 UE <--- SS

DCI 0 (UL Grant, PDCCH)

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

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
57 UE ---> SS RLC ACK  
58 UE <--- SS HARQ ACK (PHICH)

 
59

< NW >

 PHY_DATA_REQ  
60

< NW >

 MAC_DATA_REQ  
61 UE ---> SS Scheduling Request  
62 UE <--- SS

DCI 0 (UL Grant, PDCCH)

  
63

< NW >

 PHY_DATA_IND  
64

< NW >

 MAC_DATA_IND  
65

< NW >

 RLC_DATA_IND  
66

< NW >

 PDCP_DATA_IND  
67 UE ---> SS

Authentication Response

  
68 UE <--- SS HARQ ACK (PHICH)

 
69 UE <--- SS RLC ACK  
70

< NW >

 MAC_DATA_REQ  
71

< NW >

 PHY_DATA_REQ  
72 UE <--- SS

DCI 1A 

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

NAS Security Mode Command

  
74

< NW >

 PDCP_DATA_REQ  
75

< NW >

 RLC_DATA_REQ  
76

< NW >

 MAC_DATA_REQ  
77

< NW >

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

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
82

< NW >

 PHY_DATA_IND  
83

< NW >

 MAC_DATA_IND  
84 UE ---> SS RLC ACK  
85 UE <--- SS HARQ ACK (PHICH)

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

DCI 0 (UL Grant, PDCCH)

 To Send NAS Security Mode Complete
88

< NW >

 PHY_DATA_IND  
89

< NW >

 MAC_DATA_IND  
90

< NW >

 RLC_DATA_IND  
91

< NW >

 PDCP_DATA_IND  
92 UE ---> SS

NAS Security Mode  Complete

  
93 UE <--- SS HARQ ACK (PHICH)

 
94 UE <--- SS RLC ACK  
95

< NW >

 MAC_DATA_REQ  
96

< NW >

 PHY_DATA_REQ  
97 UE <--- SS DCI 1A To decode RLC ACK in UE
98 UE <--- SS

RRC Security Mode Command

  
99

< NW >

 PDCP_DATA_REQ  
100

< NW >

 RLC_DATA_REQ  
101

< NW >

 MAC_DATA_REQ  
102

< NW >

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

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
107

< NW >

 PHY_DATA_IND  
108

< NW >

 MAC_DATA_IND  
109 UE ---> SS RLC ACK  
110 UE <--- SS HARQ ACK (PHICH)

 
111 UE ---> SS Scheduling Request To send RRC Security Mode Complete from UE
112 UE <--- SS

DCI 0 (UL Grant, PDCCH)

 To send RRC Security Mode Complete from UE
113

< NW >

 PHY_DATA_IND  
114

< NW >

 MAC_DATA_IND  
115

< NW >

 RLC_DATA_IND  
116

< NW >

 PDCP_DATA_IND  
117 UE ---> SS

RRC Security Mode Complete

  
118 UE <--- SS HARQ ACK (PHICH)

 
119 UE <--- SS RLC ACK  
120

< NW >

 MAC_DATA_REQ  
121

< NW >

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

124

 UE <--- SS

RRC Connection Reconfiguration

+ Attach Accept

+ Activate Default EPS Bearer Context Request

 
125

< NW >

 PDCP_DATA_REQ  
126

< NW >

 RLC_DATA_REQ  
127

< NW >

 MAC_DATA_REQ  
128

< NW >

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

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
132

< NW >

 PHY_DATA_IND  
133

< NW >

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

DCI 0 (UL Grant, PDCCH)

 To send RRC Connection Reconfig Complete from UE
137

< NW >

 PHY_DATA_IND  
138

< NW >

 MAC_DATA_IND  
139

< NW >

 RLC_DATA_IND  
140

< NW >

 PDCP_DATA_IND  
141 UE ---> SS

RRC Connection Reconfiguration Complete

+ Attach Complete

+ Activate Default EPS Bearer Context Accept

  
142 UE <--- SS HARQ ACK (PHICH)

 
143 UE <--- SS RLC ACK  
144

< NW >

 MAC_DATA_REQ  
145

< NW >

 PHY_DATA_REQ  
146 UE <--- SS DCI 1A To decode RLC ACK in UE
147   < IP Data Traffic if needed >  
148 UE <--- SS RRC Connection Release  
149

< NW >

 PDCP_DATA_REQ  
150

< NW >

 RLC_DATA_REQ  
151

< NW >

 MAC_DATA_REQ  
152

< NW >

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

DCI 0 (UL Grant, PDCCH)

 To send RLC ACK from UE
157

< NW >

 PHY_DATA_IND  
158

< NW >

 MAC_DATA_IND  
159 UE ---> SS RLC ACK  
160 UE <--- SS HARQ ACK (PHICH)

 
161 UE < Now UE should be in IDLE mode >