Project

General

Profile

NanoBTSmultiTRX » History » Version 5

laforge, 02/19/2016 10:48 PM
Name changed from nanoBTS_multiTRX to nanoBTS/multiTRX

1 5 laforge
{{>toc}}
2 1 laforge
3
4 5 laforge
h1. How to create a nanoBTS multi-TRX setup
5 1 laforge
6 5 laforge
7
8
h2. Preparation
9
10
11 1 laforge
In order to configure an ip.access nanoBTS multi-TRX setup, you will need
12 5 laforge
* at least two nanoBTS (let's say you have N units, where 1 < N < 5)
13
* N-1 TIB cables (see section below how to make them)
14
* N-1 RF cables (see section below)
15
* N RJ45 cables
16
* N PoE capable Ethernet ports at a switch
17 1 laforge
18
19 5 laforge
h3. TIB cables
20 1 laforge
21 5 laforge
22
23
h4. The TIB connectors
24
25
26 1 laforge
As you may have noticed, the nanoBTS has two connectors called TIB-in and TIB-out.
27
TIB refers to the Timing Interface Bus, a proprietary interface to synchronize the
28
various nanoBTS units in a multi-TRX setup.
29
30
While upon first sight they may appear to be RJ-45, they are in fact not.
31
Careful inspection will show that while they have the same width as RJ-45, they
32
do actually have two extra pins (one on each side), making it a 10pin connector.
33
The official designation for those connectors is RJ-69.
34
35
The corresponding plugs and 10pin cables are relatively hard to come by.  In
36
Germany you can order them from http://www.segor.de/
37
38
Unfortunately, the RJ-69 sockets in the nanoBTS are not standard, but have a
39 5 laforge
dent on the right side (right of the connectors _nose_).  We have not been able
40 1 laforge
to find a source for the matching plugs, so we resort to milling part of the
41
standard RJ-69 plug away.
42
43
You will need two RJ-69 (10pin RJ-45) connectors for each cable.  I suggest you
44
buy some extra, in case you break one during mounting or milling.
45
46
47 5 laforge
h4. Milling the RJ-69 connector
48
49
50 1 laforge
We don't really have any mechanical specifications for the connectors.  Simply
51
use a small milling tool to remove parts of the tip of the plug until it fits
52
into the socket.
53
54
FIXME: picture of milled plug
55
56 5 laforge
h4. Crimping the RJ-69 connectors
57
58
59 1 laforge
The crimping is the same like crimping RJ-45 connectors.  Any standard crimping
60
tool should work - with the exception that the two additional pins will not be
61
pushed into the wire but still stand out.
62
63
(FIXME: Photograph)
64
65
We have used a screwdriver to manually push those two pins into the plug.  Be
66
careful not to damage the plug nor hurt yourself!
67
68
Please crimp one connector to each side of the cable, resulting in a 1:1 mapping
69
of the colors.  (FIXME: Picture)
70
71
72 5 laforge
h3. RF Cables
73
74
75 1 laforge
FIXME
76
77
78 5 laforge
h3. Completing the physical setup
79
80
81 1 laforge
You will designate one BTS as the master, and all others as slave.
82
83
Start from the master TIB-out, connect it to the first slave TIB-in.  Connect
84
the first slave TIB-out with the second slave TIB-in.  Do not create a loop,
85
but simply a chain from one unit to another.
86
87
88 5 laforge
h3. Configuring the Unit IDs
89
90
91 1 laforge
In a multi-TRX setup, the ip.access Unit IDs have to be set in a way that
92
the Site-ID and BTS-ID portions are equal, while the TRX-ID increments.
93
So for example:
94 5 laforge
* 1800/0/0 -- master BTS of multi-TRX setup
95
* 1800/0/1 -- first slave of multi-TRX setup
96
* 1800/0/2 -- second slave of multi-TRX setup (if any)
97
* 1800/0/3 -- third slave of multi-TRX setup (if any)
98 1 laforge
99 5 laforge
In order to set the Unit ID's accordingly, you can use the [[ipaccess-config]] tool.
100 1 laforge
101
In the following example, we configure the Unit IDs of two BTS.  The '-r' is for restarting
102
the BTS after the Unit ID change:
103 5 laforge
<pre>
104 1 laforge
./ipaccess-config -u 1800/0/0 -r 192.168.100.120
105
./ipaccess-config -u 1800/0/1 -r 192.168.100.190
106 5 laforge
</pre>
107 1 laforge
108 5 laforge
If we run [[ipaccess-find]] after the BTS have restarted, you will see something
109 1 laforge
along the lines of the following output:
110 5 laforge
<pre>
111
MAC Address='00:02:95:11:11:11'  IP Address='192.168.100.120'  Unit ID='1800/0/0'  Location 1=_  Location 2='BTS_NBT131G'
112 1 laforge
 Equipment Version='165a029_55'  Software Version='168a302_v142b13d0'  Unit Name='nbts-00-02-95-11-11-11'  Serial Number='00111111'
113 5 laforge
MAC Address='00:02:95:22:22:22'  IP Address='192.168.100.190'  Unit ID='1800/0/1'  Location 1=_  Location 2='BTS_NBT131G'
114 1 laforge
 Equipment Version='165a029_55'  Software Version='168a302_v142b13d0'  Unit Name='nbts-00-02-95-22-22-22'  Serial Number='00222222'
115 5 laforge
</pre>
116 1 laforge
117
The slave TRX will have a green blinking light (indicating OML connection is
118 5 laforge
up), despite your [[OpenBSC]] not even running yet.  The reson for this seems to be
119 1 laforge
the fact that the slave TRX connect their OML link to the master TRX and not
120
the BSC!
121 2 laforge
122 1 laforge
123 5 laforge
h2. Configuring [[OpenBSC]]
124
125
126
On [[OpenBSC]], you simply configure one BTS (with unit ID of the master TRX) and N
127 2 laforge
number of TRX in that BTS.  No special action required.
128
129
An example configuration file is attached to this page.
130
131
132 5 laforge
h2. Running [[OpenBSC]]
133
134
135
You run [[OpenBSC]] as usual. The master BTS will establish the OML link,
136 2 laforge
then the master TRX will establish its RSL link, followed by the slave TRX RSL links.
137
138 5 laforge
<pre>
139 2 laforge
./osmo-nitb
140
<000d> input/ipaccess.c:632 accept()ed new OML link from 192.168.100.120
141
<000d> input/ipaccess.c:237 Identified BTS 1800/0/0
142
<0005> bsc_init.c:736 bootstrapping OML for BTS 0
143
<000d> input/ipaccess.c:694 accept()ed new RSL link from 192.168.100.120
144
<000d> input/ipaccess.c:237 Identified BTS 1800/0/0
145 1 laforge
<0004> bsc_init.c:897 bootstrapping RSL for BTS/TRX (0/0) on ARFCN 871 using MCC=1 MNC=1 LAC=1 CID=0 BSIC=63 TSC=7
146
<000d> input/ipaccess.c:694 accept()ed new RSL link from 192.168.100.190
147
<000d> input/ipaccess.c:237 Identified BTS 1800/0/1
148
<0004> bsc_init.c:897 bootstrapping RSL for BTS/TRX (0/1) on ARFCN 873 using MCC=1 MNC=1 LAC=1 CID=0 BSIC=63 TSC=7
149 5 laforge
</pre>
Add picture from clipboard (Maximum size: 48.8 MB)