NanoBTSmultiTRX » History » Version 5
laforge, 02/19/2016 10:48 PM
Name changed from nanoBTS_multiTRX to nanoBTS/multiTRX
1 | 5 | laforge | {{>toc}} |
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4 | 5 | laforge | h1. How to create a nanoBTS multi-TRX setup |
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6 | 5 | laforge | |
7 | |||
8 | h2. Preparation |
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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) |
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14 | * N-1 RF cables (see section below) |
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15 | * N RJ45 cables |
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16 | * N PoE capable Ethernet ports at a switch |
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17 | 1 | laforge | |
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19 | 5 | laforge | h3. TIB cables |
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21 | 5 | laforge | |
22 | |||
23 | h4. The TIB connectors |
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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 |
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28 | various nanoBTS units in a multi-TRX setup. |
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29 | |||
30 | While upon first sight they may appear to be RJ-45, they are in fact not. |
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31 | Careful inspection will show that while they have the same width as RJ-45, they |
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32 | do actually have two extra pins (one on each side), making it a 10pin connector. |
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33 | The official designation for those connectors is RJ-69. |
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34 | |||
35 | The corresponding plugs and 10pin cables are relatively hard to come by. In |
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36 | Germany you can order them from http://www.segor.de/ |
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37 | |||
38 | Unfortunately, the RJ-69 sockets in the nanoBTS are not standard, but have a |
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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. |
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42 | |||
43 | You will need two RJ-69 (10pin RJ-45) connectors for each cable. I suggest you |
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44 | buy some extra, in case you break one during mounting or milling. |
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45 | |||
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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 |
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52 | into the socket. |
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53 | |||
54 | FIXME: picture of milled plug |
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55 | |||
56 | 5 | laforge | h4. Crimping the RJ-69 connectors |
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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 |
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61 | pushed into the wire but still stand out. |
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62 | |||
63 | (FIXME: Photograph) |
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64 | |||
65 | We have used a screwdriver to manually push those two pins into the plug. Be |
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66 | careful not to damage the plug nor hurt yourself! |
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67 | |||
68 | Please crimp one connector to each side of the cable, resulting in a 1:1 mapping |
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69 | of the colors. (FIXME: Picture) |
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70 | |||
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72 | 5 | laforge | h3. RF Cables |
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74 | |||
75 | 1 | laforge | FIXME |
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78 | 5 | laforge | h3. Completing the physical setup |
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81 | 1 | laforge | You will designate one BTS as the master, and all others as slave. |
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83 | Start from the master TIB-out, connect it to the first slave TIB-in. Connect |
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84 | the first slave TIB-out with the second slave TIB-in. Do not create a loop, |
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85 | but simply a chain from one unit to another. |
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88 | 5 | laforge | h3. Configuring the Unit IDs |
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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. |
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93 | So for example: |
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94 | 5 | laforge | * 1800/0/0 -- master BTS of multi-TRX setup |
95 | * 1800/0/1 -- first slave of multi-TRX setup |
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96 | * 1800/0/2 -- second slave of multi-TRX setup (if any) |
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97 | * 1800/0/3 -- third slave of multi-TRX setup (if any) |
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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 |
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102 | the BTS after the Unit ID change: |
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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 |
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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' |
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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 |
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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! |
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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 |
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127 | 2 | laforge | number of TRX in that BTS. No special action required. |
128 | |||
129 | An example configuration file is attached to this page. |
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130 | |||
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132 | 5 | laforge | h2. Running [[OpenBSC]] |
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135 | You run [[OpenBSC]] as usual. The master BTS will establish the OML link, |
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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 |
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141 | <000d> input/ipaccess.c:237 Identified BTS 1800/0/0 |
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142 | <0005> bsc_init.c:736 bootstrapping OML for BTS 0 |
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143 | <000d> input/ipaccess.c:694 accept()ed new RSL link from 192.168.100.120 |
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144 | <000d> input/ipaccess.c:237 Identified BTS 1800/0/0 |
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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 |
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147 | <000d> input/ipaccess.c:237 Identified BTS 1800/0/1 |
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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 |
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149 | 5 | laforge | </pre> |