Project

General

Profile

L1A L23 Interface » History » Version 1

laforge, 02/19/2016 10:48 PM
describe the minimal required interface between L1A and L23

1 1 laforge
= Minimalistic L1 interface =
2
3
This is the description of the minimal interface between L1 and higher layers (L23)
4
neccessary to establish a dedicated channel with the cell and perform procedures like
5
LOCATION UPDATE or AUTHENTICAITON.
6
7
== Message Types ==
8
9
=== SYNC_NEW_CCCH_REQ ===
10
11
Triggers the following actions in L1:
12
 * switch to new ARFCN
13
 * perform AGC + AFC
14
 * synchronize to FCCH
15
 * decode SCH and determine frame number
16
17
==== parameters ====
18
 * ARFCN + BAND
19
20
==== response ====
21
 * SYNC_NEW_CCCH_RESP
22
23
24
=== SYNC_NEW_CCCH_RESP ===
25
Sent from the L1 to the L23 after it has synchronized to a new cell (FCCH and SCH acquisition)
26
27
==== parameters ====
28
 * struct l1_info_dl
29
  * ARFCN + BAND
30
  * GSM frame number (t1/t2/t3)
31
  * Rx Level
32
  * SNR
33
 * BSIC
34
35
36
=== CCCH_INFO_IND ===
37
38
Sent by the L1 to the L23 whenever it has successfully decoded four consecutive bursts on
39
the CCCH.
40
41
It is up to the L23 to decide whether the burst belongs to BCCH, AGCH, PCH or SDCCH/4.
42
43
==== parameters ====
44
 * ARFCN + BAND
45
 * GSM frame number
46
 * Rx Level
47
 * SNR
48
 * 33 bytes L1 payload
49
50
51
=== RACH_REQ ===
52
53
Sent from the L23 to the L1 to instruct the L1 to send a RACH request to the current cell.
54
55
==== parameters ====
56
 * struct l1_info_ul
57
  * Tx power
58
  * TDMA frame number
59
  * channel type
60
  * channel number (timeslot, subslot)
61
 * 8 bit RA Reference
62
63
64
==== response ====
65
No response by L1.
66
67
The response by the serving cell will be an IMMEDIATE ASSIGNMENT in the AGCH on
68
the CCCH downlink.
69
70
71
=== DEDIC_MODE_EST_REQ ===
72
73
Sent from the L23 to the L1 to instruct switching from CCCH mode to a dedicated
74
channel.
75
76
Initially we only implement SDCCH/4 and SDCCH/8 on a non-hopping cell.
77
78
==== parameters ====
79
 * struct l1_info_ul
80
 * (arfcn|hsn,maio)
81
82
83
=== DEDIC_MODE_DATA_IND ===
84
85
Sent by the L1 to the L23 to convey the successful reception of four
86
consecutive bursts on the dedicated channel.
87
88
It is up to the L23 to do the time demultiplex of multiple SDCCHs in the same
89
on-air timeslot.
90
91
==== parameters ====
92
 * struct l1_info_dl
93
 * 33 bytes L1 payload
94
95
96
=== DEDIC_MODE_DATA_REQ ===
97
Sent by the L23 to the L1 to send payload data on a dedicated channel such as
98
SDCCH.
99
100
==== parameters ====
101
 * struct l1_info_ul
102
 * 33 byte L1 payload
Add picture from clipboard (Maximum size: 48.8 MB)