Difference between revisions of "OpenBTS: Kalibrasi"

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Jika kita tidak mempunyai peralatan lab yang baik dan kita ingin mengetahui akurasi clock USRP, kita dapat menggunakan aplikasi Kalibrator (Copyright (c) 2009 Joshua Lackey, Alexander Chemeris). Tentunya kita tidak mungkin memperoleh hasil yang baik seperti hi-tech lab, tapi cukup lah untuk mengetahui error kalibrasi clock yang ada.
 
Jika kita tidak mempunyai peralatan lab yang baik dan kita ingin mengetahui akurasi clock USRP, kita dapat menggunakan aplikasi Kalibrator (Copyright (c) 2009 Joshua Lackey, Alexander Chemeris). Tentunya kita tidak mungkin memperoleh hasil yang baik seperti hi-tech lab, tapi cukup lah untuk mengetahui error kalibrasi clock yang ada.
 
 
 
Latest version of Kalibrator today is 0.2 and is available [http://sourceforge.net/mailarchive/attachment.php?list_name=openbts-discuss&message_id=3d032e5d0911101431o5bb31844mdfe80ae4fc9789ea@mail.gmail.com&counter=1 here]. Starting from the next update of OpenBTS Kalibrator will be distributed as a part of OpenBTS standard package.
 
 
How it works¶
 
 
Kalibrator takes advantage of the existing real networks and their accuracy. So you need to be in range within some operator's BTS. You pass the downlink frequency of the previously scanned ARFCN as a command line parameter for Kalibrator. Using some math Kalibrator can estimate the value of frequency difference between the frequency it tunes USRP to and the frequency of a BTS working in +-200kHz range near that frequency.
 
 
Building and running¶
 
 
To build Kalibrator with gnuradio 3.2.2 (ver. 3.1.3 is not currently supported) run 'make' and you will get binary file 'kal' which is ready for use.
 
 
Now you need to know which ARFCN is better to use. With any GPRS modem supporting AT commands it is possible to find an ARFCN with the strongest signal. Without such modem, you have to scan whole band by manual iteration through downlink frequencies (it can be inconvenient especially on 1800/1900 band). Search this file for specific downlinks all_gsm_channels_arfcn.txt.
 
 
Suitable channels must have at least -70 to -80dBm strenght, else you got to much overruns and the result could be misguiding. That's just good to have more channels to scan to eliminate possible wrong error. There is an example of network scan from GPRS modem (offset values are added manually).
 
 
T-Mobile operator
 
=================
 
 
at^moni
 
Serving Cell                                          I Dedicated channel
 
chann rs  dBm MCC MNC  LAC cell NCC BCC PWR RXLev  C1 I chann TS timAdv PWR  dBm Q ChMod    offset
 
    58 53  -57 230  01 4358 719D  2  4  33  -106  48 I    Limited Service            -2197 Hz
 
 
OK
 
 
at^monp
 
chann rs  dBm MCC MNC BCC  C1  C2    offset
 
  106 45  -65 230  01  7  40  40    -2507 Hz
 
    75 37  -73 230  01  2  32  32    -2367 Hz
 
    28 21  -89 230  01  4  16  16    N/A
 
    80 17  -93 230  01  1  12  12    N/A 
 
 
OK
 
 
Telefonica O2 operator
 
======================
 
at^moni
 
Serving Cell                                      Z  I Dedicated channel
 
chann rs  dBm MCC MNC  LAC cell NCC BCC PWR RXLev  C1 I chann TS timAdv PWR  dBm Q ChMod    offset
 
    86 59  -51 230  02 04BC 090B  1  3  33  -106  54 I    Limited Service            -2496 Hz
 
 
OK
 
at^monp
 
chann rs  dBm MCC MNC BCC  C1  C2    offset
 
  114 47  -63 230  02  4  42  42    N/A
 
  112 30  -80 230  02  7  25  25    N/A
 
    93 19  -91 230  02  7  14  14    N/A
 
 
OK
 
 
Here is obvious how the values were obtained.
 
 
[openBTS@openBTS kal-0.2]# ./kal -f 946600000 -u
 
USRP side: B
 
FPGA clock: 52000000
 
Decimation: 192
 
Antenna: RX2
 
Sample rate: 270833.343750
 
average [min, max] (range, stddev)
 
-2197.789062 [-2431, -1843] (588, 146.761444)
 
overruns: 0
 
not found: 0
 
 
[openBTS@openBTS kal-0.2]# ./kal -f 956200000 -u
 
USRP side: B
 
FPGA clock: 52000000
 
Decimation: 192
 
Antenna: RX2
 
Sample rate: 270833.343750
 
average [min, max] (range, stddev)
 
-2507.531006 [-2575, -2436] (139, 40.815132)
 
overruns: 0
 
not found: 0
 
 
[openBTS@openBTS kal-0.2]# ./kal -f 950000000 -u
 
USRP side: B
 
FPGA clock: 52000000
 
Decimation: 192
 
Antenna: RX2
 
Sample rate: 270833.343750
 
average [min, max] (range, stddev)
 
-2367.053467 [-2431, -2275] (156, 43.972340)
 
overruns: 0
 
not found: 0
 
 
[openBTS@openBTS kal-0.2]# ./kal -f 952200000 -u
 
USRP side: B
 
FPGA clock: 52000000
 
Decimation: 192
 
Antenna: RX2
 
Sample rate: 270833.343750
 
average [min, max] (range, stddev)
 
-2496.760254 [-2592, -2375] (217, 61.745182)
 
overruns: 0
 
not found: 0
 
 
By default RX and side are set to ones used by OpenBTS, so usually you need only one mandatory parameter '-f'. You can use -u is optional parameter for continous display.
 
 
... page in progress
 
 
  
 
==Download==
 
==Download==
Line 111: Line 9:
  
 
  http://thre.at/kalibrate/kal-v0.4.1.tar.bz2
 
  http://thre.at/kalibrate/kal-v0.4.1.tar.bz2
 
+
git clone https://github.com/ttsou/kalibrate-uhd kalibrate-uhd
  
 
==Compile==
 
==Compile==
Line 120: Line 18:
 
  cd /usr/local/src/kal-v0.4.1
 
  cd /usr/local/src/kal-v0.4.1
 
  ./bootstrap && CXXFLAGS='-W -Wall -O3' ./configure && make
 
  ./bootstrap && CXXFLAGS='-W -Wall -O3' ./configure && make
 
  
 
==Menjalankan==
 
==Menjalankan==
Line 190: Line 87:
 
===Scanning 900===
 
===Scanning 900===
  
Menjalankan  
+
Untuk Clock 64MHz Menjalankan  
  
 
  cd /usr/local/src/kal-v0.4.1/src/
 
  cd /usr/local/src/kal-v0.4.1/src/
 
  ./kal -s 900 -F 64000000 -b GSM900
 
  ./kal -s 900 -F 64000000 -b GSM900
 +
 +
Untuk Clock 52MHz Menjalankan
 +
 +
cd /usr/local/src/kal-v0.4.1/src/
 +
./kal -s 900 -F 52000000 -b GSM900 -vv
  
 
Hasil
 
Hasil
  
 +
FPGA clock : 52000000
 +
Decimation : 192
 +
Sample rate: 270833.343750
 
  kal: Scanning for GSM-900 base stations.
 
  kal: Scanning for GSM-900 base stations.
 +
channel detect threshold: 9458.928125
 
  GSM-900:
 
  GSM-900:
 +
chan: 36 (942.2MHz + 423Hz) power: 194131.34
 +
chan: 37 (942.4MHz + 428Hz) power: 50474.90
 +
chan: 38 (942.6MHz + 412Hz) power: 50189.51
 +
chan: 39 (942.8MHz + 397Hz) power: 14175.00
 +
chan: 40 (943.0MHz + 483Hz) power: 38742.63
 +
chan: 41 (943.2MHz + 510Hz) power: 50648.68
 +
chan: 61 (947.2MHz + 503Hz) power: 73085.29
 +
chan: 62 (947.4MHz + 490Hz) power: 18121.82
 +
chan: 66 (948.2MHz + 512Hz) power: 16138.32
 +
chan: 68 (948.6MHz + 491Hz) power: 18167.35
 +
chan: 113 (957.6MHz + 548Hz) power: 24349.49
 +
chan: 114 (957.8MHz + 493Hz) power: 11841.20
 +
chan: 115 (958.0MHz + 520Hz) power: 20344.80
 +
chan: 119 (958.8MHz + 505Hz) power: 31772.62
 +
chan: 120 (959.0MHz + 535Hz) power: 10510.76
 +
chan: 123 (959.6MHz + 565Hz) power: 18004.66
  
 
===Scanning 850===
 
===Scanning 850===
Line 205: Line 127:
  
 
  cd /usr/local/src/kal-v0.4.1/src/
 
  cd /usr/local/src/kal-v0.4.1/src/
  ./kal -s 850 -F 64
+
  ./kal -s 850 -F 64000000
  
 
Hasil
 
Hasil
Line 214: Line 136:
  
 
  cd /usr/local/src/kal-v0.4.1/src/
 
  cd /usr/local/src/kal-v0.4.1/src/
./kal -c 513 -F 64000000 -b DCS
+
./kal -c 513 -F 64000000 -b DCS
  
 
Hasil
 
Hasil
Line 224: Line 146:
 
  overruns: 0
 
  overruns: 0
 
  not found: 0
 
  not found: 0
 +
 +
 +
==Kalkulasi Kalibrasi==
 +
 +
Misalnya kita menggunakan BTS pada channel 47 untuk kalibrasi
 +
 +
./kal -F 52000000 -c 47
 +
 +
Hasil
 +
 +
kal: Calculating clock frequency offset.
 +
Using GSM-900 channel 47 (944.4MHz)
 +
average [min, max] (range, stddev)
 +
+ 501Hz [479, 524] (45, 13.227342)
 +
overruns: 0
 +
not found: 0
 +
 +
 +
Misalnya kita menggunakan BTS pada channel 61 untuk kalibrasi
 +
 +
./kal -F 52000000 -c 61
 +
 +
Hasil
 +
 +
kal: Calculating clock frequency offset.
 +
Using GSM-900 channel 61 (947.2MHz)
 +
average [min, max] (range, stddev)
 +
+ 494Hz [481, 504] (23, 6.454695)
 +
overruns: 0
 +
not found: 0
 +
 +
 +
==Proses Kalibrasi==
 +
 +
===Ukur===
 +
 +
Gunakan Kalibrate untuk mengukur offset frekuensi, misalnya pada channel 52
 +
 +
./kal -f 945400000
 +
 +
Misalnya hasilnya adalah
 +
 +
kal: Calculating clock frequency offset.
 +
Using GSM-900 channel 52 (945.4MHz)
 +
average [min, max] (range, stddev)
 +
+ 498Hz [429, 555] (126, 32.384548)
 +
overruns: 0
 +
not found: 165
 +
 +
===Hitung Offset===
 +
 +
Hitung dengan asumsi
 +
 +
* Frekuensi Clock  20MHz
 +
* Kanal 52 atau frekuensi 945.4MHz
 +
* Offset hasil pengukuran + 500Hz
 +
 +
Maka clock 20MHz harus di offset sebesar
 +
 +
-500Hz/945.4MHz*20MHz=-10.6 Hz
 +
 +
Tepatnya menjadi
 +
 +
19,999,990 Hz
 +
 +
===Set Ulang ClockTamer===
 +
 +
Set ulang OSC pada ClockTamer menggunakan
 +
 +
sudo screen /dev/ttyACM0 115200,cs8,-ixon,-ixoff
 +
 +
Beberapa pilihan setting
 +
 +
SET,,OSC,19999991
 +
SET,,OSC,19999990
 +
SET,,OSC,19999989
 +
STE
 +
 +
===Scan Ulang Frekuensi===
 +
 +
Hasilnya harus lebih baik
 +
 +
cd /usr/local/src/kal-v0.4.1/src
 +
./kal -s 900 -F 52000000 -b GSM900 -vv
 +
 +
Semoga hasilnya memperoleh offset yang lebih baik, seperti
 +
 +
FPGA clock : 52000000
 +
Decimation : 192
 +
Sample rate: 270833.343750
 +
kal: Scanning for GSM-900 base stations.
 +
channel detect threshold: 6922.106769
 +
GSM-900:
 +
chan: 36 (942.2MHz -  34Hz) power: 192896.03
 +
chan: 37 (942.4MHz -  30Hz) power: 48710.69
 +
chan: 38 (942.6MHz -  13Hz) power: 31109.57
 +
chan: 64 (947.8MHz +  68Hz) power: 15319.56
 +
chan: 66 (948.2MHz +  65Hz) power: 14363.92
 +
chan: 109 (956.8MHz +  2Hz) power: 12547.61
 +
chan: 112 (957.4MHz -  88Hz) power: 10748.52
 +
chan: 113 (957.6MHz +  42Hz) power: 22609.95
 +
chan: 114 (957.8MHz +  36Hz) power: 18037.21
 +
chan: 115 (958.0MHz +  61Hz) power: 15508.45
 +
chan: 116 (958.2MHz +  80Hz) power: 10971.88
 +
chan: 119 (958.8MHz +  65Hz) power: 24555.23
 +
chan: 123 (959.6MHz +  25Hz) power: 16705.38
  
 
==Referensi==
 
==Referensi==
Line 237: Line 265:
  
 
* [[OpenBTS]]
 
* [[OpenBTS]]
 +
* [[OpenBTS: Arsitektur secara umum]]
  
 
===Persiapan===
 
===Persiapan===
Line 242: Line 271:
 
* [[USRP: High Precision Clock]]
 
* [[USRP: High Precision Clock]]
 
* [[USRP: Menyambungkan ClockTamer ke USRP1]]
 
* [[USRP: Menyambungkan ClockTamer ke USRP1]]
 +
* [[USRP: Kalibrasi ClockTamer]]
 +
* [[USRP: ClockTamer Control Protocol]]
 
* [[USRP: Instalasi Board]]
 
* [[USRP: Instalasi Board]]
 
* [[OpenBTS: GIT Source Code]]
 
* [[OpenBTS: GIT Source Code]]
 +
* [[USRP: Rangkaian Board USRP]]
 +
* [[OpenBTS: Tethr untuk Bencana Alam]]
  
 
===OpenBTS 2.6===
 
===OpenBTS 2.6===
Line 249: Line 282:
 
* [[GNURadio]]
 
* [[GNURadio]]
 
* [[GNURadio: Ubuntu Install]]
 
* [[GNURadio: Ubuntu Install]]
* [[GNURadio: Ubuntu Install GNURadio 3.4.2]]
+
* [[GNURadio: Menggunakan UHD]]
 +
* [[GNURadio: Ubuntu Install GNURadio 3.4.2]] '''RECOMMENDED'''
 +
* [[GNURadio: Ubuntu Install GNURadio 3.4.2 Clock 52MHz]] '''RECOMMENDED'''
 
* [[GNURadio: Contoh Aplikasi]]
 
* [[GNURadio: Contoh Aplikasi]]
 
* [[GNURadio: Spectrum Analizer GSM]]
 
* [[GNURadio: Spectrum Analizer GSM]]
 
* [[GNURadio: Mengubah board RFX1800 menjadi RFX900]]
 
* [[GNURadio: Mengubah board RFX1800 menjadi RFX900]]
 
* [[GNURadio: Programming Untuk Pemula]]
 
* [[GNURadio: Programming Untuk Pemula]]
* [[OpenBTS: Ubuntu Install]]
+
* [[OpenBTS: Ubuntu Install]] '''RECOMMENDED'''
* [[OpenBTS: Konfigurasi]]
+
* [[OpenBTS: Ubuntu Install OpenBTS 2.6 Clock 52MHz]] '''RECOMMENDED'''
 +
* [[OpenBTS: Konfigurasi]] '''RECOMMENDED'''
 
* [[OpenBTS: Kalibrasi]]
 
* [[OpenBTS: Kalibrasi]]
* [[OpenBTS: Konfigurasi Asterisk untuk OpenBTS]]
+
* [[OpenBTS: Konfigurasi Asterisk untuk OpenBTS]] '''RECOMMENDED'''
 
* [[OpenBTS: Menjalankan smqueue]]
 
* [[OpenBTS: Menjalankan smqueue]]
* [[OpenBTS: Mengoperasikan BTS]]
+
* [[OpenBTS: Mengoperasikan BTS]] '''RECOMMENDED'''
 
* [[OpenBTS: Tampilan di Nokia saat pakai OpenBTS]]
 
* [[OpenBTS: Tampilan di Nokia saat pakai OpenBTS]]
 
* [[OpenBTS: Operasi 1800 MHz]]
 
* [[OpenBTS: Operasi 1800 MHz]]
Line 270: Line 306:
 
===OpenBTS 2.8===
 
===OpenBTS 2.8===
  
* [[GNURadio: Ubuntu 11.10 Install]] '''*NOT RECOMMENED*'''
+
* [[GNURadio: Ubuntu 11.10 Install]] ''NOT RECOMMENED''
* [[GNURadio: Ubuntu 11.10 instalasi menggunakan Repo]] '''NOT RECOMMENDED'''
+
* [[GNURadio: Ubuntu 11.10 instalasi menggunakan Repo]] ''NOT RECOMMENDED''
 +
* [[GNURadio: Download GNURadio]]
 +
* [[GNURadio: Install UHD]]
 
* [[GNURadio: Ubuntu 11.10 Instal GNURadio 3.3.0]]
 
* [[GNURadio: Ubuntu 11.10 Instal GNURadio 3.3.0]]
* [[GNURadio: Ubuntu 11.10 Instal GNURadio 3.4.2]]
+
* [[GNURadio: Ubuntu 11.10 Instal GNURadio 3.4.2]] '''RECOMMENDED'''
* [[GNURadio: Ubuntu 11.10 Install dari GIT GNURadio]]
+
* [[GNURadio: Ubuntu 12.04 Instal GNURadio 3.4.2]] '''RECOMMENDED'''
 +
* [[GNURadio: Ubuntu 11.10 Instal GNURadio 3.5.0]] ''NOT RECOMMENDED''
 +
* [[GNURadio: Ubuntu 11.10 Instal GNURadio 3.5.3.2]] ''NOT RECOMMENDED''
 +
* [[GNURadio: Ubuntu 11.10 Instal GNURadio 3.6.0]] ''NOT RECOMMENDED''
 +
* [[GNURadio: Ubuntu 11.10 Install dari GIT GNURadio]] ''NOT RECOMMENDED''
 +
* [[GNURadio: Ubuntu 11.10 cek USRP Daughter Board]]
 +
* [[GNURadio: UHD]] ''NOT RECOMMENDED''
 +
* [[GNURadio: UHD Image]] ''NOT RECOMMENDED''
 +
* [[GNURadio: UHD burn EEPROM RFX Board di USRP1]] ''NOT RECOMMENDED''
 +
* [[GNURadio: UHD Identifikasi Device]]
 
* [[OpenBTS: Ubuntu 11.10 Install]]
 
* [[OpenBTS: Ubuntu 11.10 Install]]
* [[OpenBTS: 2.8 dari SVN Install]] '''RECOMMENDED'''
+
* [[OpenBTS: dari GIT ttsou]]
* [[OpenBTS: 2.8 Instalasi Real Time Asterisk]]
+
* [[OpenBTS: 2.8 dari SVN Install]]
 +
* [[OpenBTS: 2.8 dari SVN Install Clock 52MHz]] '''RECOMMENDED'''
 +
* [[OpenBTS: 2.8 dari SVN Install Clock 52MHz dengan UHD tanpa GNURadio]] ''NOT RECOMMENDED''
 +
* [[OpenBTS: 2.8 Edit User di sqlite3.db]] '''RECOMMEND'''
 +
* [[OpenBTS: Yate Softswitch]] '''RECOMMENDED'''
 +
* [[OpenBTS: Yate Config Test]]
 +
* [[OpenBTS: 2.8 Instalasi Real Time Asterisk]] '''RECOMMENDED'''
 +
* [[OpenBTS: 2.8 Menjalankan]] '''RECOMMENDED'''
 
* [[OpenBTS: 2.8 Konfigurasi]]
 
* [[OpenBTS: 2.8 Konfigurasi]]
 +
* [[OpenBTS: 2.8 Konfigurasi Subscriber Registery]]
 
* [[OpenBTS: Database SQLite]]
 
* [[OpenBTS: Database SQLite]]
 +
 +
===Multi OpenBTS 2.8===
 +
 +
* [[OpenBTS: Pola Multi OpenBTS]] '''RECOMMENDED'''
 +
* [[Multi OpenBTS: Catatan Konfigurasi]] '''RECOMMENDED'''
  
 
===Ettus E110===
 
===Ettus E110===
  
 
* [[OpenBTS: E110 Cara Login]]
 
* [[OpenBTS: E110 Cara Login]]
* [[OpenBTS: E110 Install Image di MicroSD]]
+
* [[OpenBTS: E110 Install Image di MicroSD]] '''*RECOMMENDED*'''
 
* [[OpenBTS: E110 Cek Daughter Board]]
 
* [[OpenBTS: E110 Cek Daughter Board]]
 
* [[OpenBTS: E110 Mengubah Master Clock]]
 
* [[OpenBTS: E110 Mengubah Master Clock]]
 +
* [[OpenBTS: E110 Kalibrasi Clock]]
 
* [[OpenBTS: E110 Bekerja dengan opkg]]
 
* [[OpenBTS: E110 Bekerja dengan opkg]]
 
* [[OpenBTS: E110 GNURadio]]
 
* [[OpenBTS: E110 GNURadio]]
 +
* [[OpenBTS: E110 Compile UHD]] '''*RECOMMENDED*'''
 +
* [[OpenBTS: E110 UHD burn EEPROM RFX Board]] '''*RECOMMENDED*'''
 +
* [[OpenBTS: E110 Install UHD Image]] '''*RECOMMENDED*'''
 
* [[OpenBTS: E110 Instalasi OpenBTS]]
 
* [[OpenBTS: E110 Instalasi OpenBTS]]
* [[OpenBTS: E110 Instalasi OpenBTS 2.6]] '''*NOT RECOMMENDED*'''
+
* [[OpenBTS: E110 Instalasi OpenBTS 2.6]] ''NOT RECOMMENDED''
 +
* [[OpenBTS: E110 Instalasi OpenBTS 2.8 untuk MultiBTS]] '''*RECOMMENDED*'''
 +
 
 +
===GPRS===
 +
 
 +
* [[OpenBTS: GPRS]]
 +
 
 +
===Power Amplifier===
 +
 
 +
* [[Driver 900MHz]]
 +
* [[Power Amplifier 900MHz]]
 +
* [[Duplexer]]
  
 
===Lain Lain===
 
===Lain Lain===
  
 +
* [[OpenBTS: Materi Magang di ICTWATCH]]
 +
* [[OpenBTS: Seminar Outline]]
 +
* [[OpenBTS: Workshop Outline]]
 
* [[Membuat Base Station GSM Open Source]]
 
* [[Membuat Base Station GSM Open Source]]
 
* [[Teknologi Selular]]
 
* [[Teknologi Selular]]
Line 309: Line 387:
 
* [[Siapa Bilang OpenBTS Ilegal?]]
 
* [[Siapa Bilang OpenBTS Ilegal?]]
 
* [[OpenBTS: Catatan MNC dan MCC Indonesia]]
 
* [[OpenBTS: Catatan MNC dan MCC Indonesia]]
 +
* [[OpenBTS: Catatan MNC dan MCC COOL]]
 
* [[OpenBTS : Alokasi Frekuensi Operator GSM Indonesia]]
 
* [[OpenBTS : Alokasi Frekuensi Operator GSM Indonesia]]
 +
* [[GSM: Daftar Channel Frekuensi]]
  
 
===Catatan Sejarah===
 
===Catatan Sejarah===
Line 316: Line 396:
 
* [[OpenBTS: Daftar Workshop atau Seminar yang pernah dilakukan]]
 
* [[OpenBTS: Daftar Workshop atau Seminar yang pernah dilakukan]]
 
* [[OpenBTS: Daftar Artikel di Media]]
 
* [[OpenBTS: Daftar Artikel di Media]]
 +
 +
===Dokumentasi Video===
 +
 +
* http://youtu.be/8ogOcUSpINU (1/6)
 +
* http://youtu.be/F5d7HGuhppk (2/6)
 +
* http://youtu.be/90Jgq6bOgrQ (3/6)
 +
* http://youtu.be/cNkx_qNqdfc (4/6)
 +
* http://youtu.be/6LCuoeI57ak (5/6)
 +
* http://youtu.be/-dEqcHoIlYk (6/6)
  
 
[[Category: Wireless]]
 
[[Category: Wireless]]
 
[[Category: Selular]]
 
[[Category: Selular]]

Latest revision as of 07:23, 14 August 2012

Sumber: http://gnuradio.org/redmine/wiki/1/OpenBTSClockCalibration


Jika kita tidak mempunyai peralatan lab yang baik dan kita ingin mengetahui akurasi clock USRP, kita dapat menggunakan aplikasi Kalibrator (Copyright (c) 2009 Joshua Lackey, Alexander Chemeris). Tentunya kita tidak mungkin memperoleh hasil yang baik seperti hi-tech lab, tapi cukup lah untuk mengetahui error kalibrasi clock yang ada.

Download

Download dari

http://thre.at/kalibrate/kal-v0.4.1.tar.bz2
git clone https://github.com/ttsou/kalibrate-uhd kalibrate-uhd

Compile

cp kal-v0.4.1.tar.bz2 /usr/local/src/
cd /usr/local/src
tar jxvf kal-v0.4.1.tar.bz2 
cd /usr/local/src/kal-v0.4.1
./bootstrap && CXXFLAGS='-W -Wall -O3' ./configure && make

Menjalankan

cd /usr/local/src/kal-v0.4.1/src/
./kal -h

Hasil

kalibrate v0.4.1, Copyright (c) 2010, Joshua Lackey

Usage:
	GSM Base Station Scan:
		kal <-s band indicator> [options]

	Clock Offset Calculation:
		kal <-f frequency | -c channel> [options]

Where options are:
	-s	band to scan (GSM850, GSM900, EGSM, DCS, PCS) 
	-f	frequency of nearby GSM base station
	-c	channel of nearby GSM base station
	-b	band indicator (GSM850, GSM900, EGSM, DCS, PCS)
	-R	side A (0) or B (1), defaults to B
	-A	antenna TX/RX (0) or RX2 (1), defaults to RX2
	-g	gain as % of range, defaults to 45%
	-F	FPGA master clock frequency, defaults to 52MHz
	-v	verbose
	-D	enable debug messages
	-h	help

Scanning 1800

Menjalankan

cd /usr/local/src/kal-v0.4.1/src/
./kal -s 1800 -F 64000000 -b DCS

Hasil

kal: Scanning for DCS-1800 base stations.
DCS-1800:
 	chan: 513 (1805.4MHz + 14.952kHz)	power: 5336.89 
	chan: 514 (1805.6MHz + 14.954kHz)	power: 1927.35
	chan: 517 (1806.2MHz + 14.952kHz)	power: 3715.71
	chan: 518 (1806.4MHz + 14.983kHz)	power: 1717.65
	chan: 519 (1806.6MHz + 14.969kHz)	power: 5159.38
	chan: 520 (1806.8MHz + 14.951kHz)	power: 2017.03
	chan: 542 (1811.2MHz + 15.092kHz)	power: 4554.77
	chan: 544 (1811.6MHz + 15.084kHz)	power: 3730.97
	chan: 569 (1816.6MHz + 15.181kHz)	power: 6196.37
	chan: 570 (1816.8MHz + 15.172kHz)	power: 1924.81
	chan: 613 (1825.4MHz + 15.237kHz)	power: 15746.19
	chan: 614 (1825.6MHz + 15.242kHz)	power: 6683.53
	chan: 616 (1826.0MHz + 15.260kHz)	power: 12953.63
	chan: 617 (1826.2MHz + 15.248kHz)	power: 4816.39
	chan: 620 (1826.8MHz + 15.224kHz)	power: 4274.58
	chan: 625 (1827.8MHz + 15.268kHz)	power: 3613.13
	chan: 626 (1828.0MHz + 15.313kHz)	power: 1926.56
	chan: 627 (1828.2MHz + 15.274kHz)	power: 3536.15
	chan: 628 (1828.4MHz + 15.267kHz)	power: 2346.39
	chan: 629 (1828.6MHz + 15.288kHz)	power: 7923.44
 	chan: 632 (1829.2MHz + 15.316kHz)	power: 5417.85
 	chan: 633 (1829.4MHz + 15.312kHz)	power: 2652.96
   	chan: 689 (1840.6MHz + 15.602kHz)	power: 3734.25
 	chan: 692 (1841.2MHz + 15.587kHz)	power: 11674.51
	chan: 693 (1841.4MHz + 15.586kHz)	power: 5294.69

Scanning 900

Untuk Clock 64MHz Menjalankan

cd /usr/local/src/kal-v0.4.1/src/
./kal -s 900 -F 64000000 -b GSM900

Untuk Clock 52MHz Menjalankan

cd /usr/local/src/kal-v0.4.1/src/
./kal -s 900 -F 52000000 -b GSM900 -vv

Hasil

FPGA clock : 52000000
Decimation : 192
Sample rate: 270833.343750
kal: Scanning for GSM-900 base stations.
channel detect threshold: 9458.928125
GSM-900:
	chan: 36 (942.2MHz + 423Hz)	power: 194131.34 
	chan: 37 (942.4MHz + 428Hz)	power: 50474.90
	chan: 38 (942.6MHz + 412Hz)	power: 50189.51
	chan: 39 (942.8MHz + 397Hz)	power: 14175.00
	chan: 40 (943.0MHz + 483Hz)	power: 38742.63
	chan: 41 (943.2MHz + 510Hz)	power: 50648.68
	chan: 61 (947.2MHz + 503Hz)	power: 73085.29
	chan: 62 (947.4MHz + 490Hz)	power: 18121.82
	chan: 66 (948.2MHz + 512Hz)	power: 16138.32
	chan: 68 (948.6MHz + 491Hz)	power: 18167.35
	chan: 113 (957.6MHz + 548Hz)	power: 24349.49
	chan: 114 (957.8MHz + 493Hz)	power: 11841.20
	chan: 115 (958.0MHz + 520Hz)	power: 20344.80
	chan: 119 (958.8MHz + 505Hz)	power: 31772.62
	chan: 120 (959.0MHz + 535Hz)	power: 10510.76
	chan: 123 (959.6MHz + 565Hz)	power: 18004.66

Scanning 850

Menjalankan

cd /usr/local/src/kal-v0.4.1/src/
./kal -s 850 -F 64000000

Hasil

Scanning Channel

Menjalankan

cd /usr/local/src/kal-v0.4.1/src/
./kal -c 513 -F 64000000 -b DCS

Hasil

kal: Calculating clock frequency offset.
Using DCS-1800 channel 513 (1805.4MHz)
average		[min, max]	(range, stddev)
+ 17.109kHz		[17087, 17136]	(50, 14.080007)
overruns: 0
not found: 0


Kalkulasi Kalibrasi

Misalnya kita menggunakan BTS pada channel 47 untuk kalibrasi

./kal -F 52000000 -c 47

Hasil

kal: Calculating clock frequency offset.
Using GSM-900 channel 47 (944.4MHz)
average		[min, max]	(range, stddev)
+ 501Hz		[479, 524]	(45, 13.227342)
overruns: 0
not found: 0


Misalnya kita menggunakan BTS pada channel 61 untuk kalibrasi

./kal -F 52000000 -c 61

Hasil

kal: Calculating clock frequency offset.
Using GSM-900 channel 61 (947.2MHz)
average		[min, max]	(range, stddev)
+ 494Hz		[481, 504]	(23, 6.454695)
overruns: 0
not found: 0


Proses Kalibrasi

Ukur

Gunakan Kalibrate untuk mengukur offset frekuensi, misalnya pada channel 52

./kal -f 945400000

Misalnya hasilnya adalah

kal: Calculating clock frequency offset.
Using GSM-900 channel 52 (945.4MHz)
average		[min, max]	(range, stddev)
+ 498Hz		[429, 555]	(126, 32.384548)
overruns: 0
not found: 165

Hitung Offset

Hitung dengan asumsi

  • Frekuensi Clock 20MHz
  • Kanal 52 atau frekuensi 945.4MHz
  • Offset hasil pengukuran + 500Hz

Maka clock 20MHz harus di offset sebesar

-500Hz/945.4MHz*20MHz=-10.6 Hz

Tepatnya menjadi

19,999,990 Hz

Set Ulang ClockTamer

Set ulang OSC pada ClockTamer menggunakan

sudo screen /dev/ttyACM0 115200,cs8,-ixon,-ixoff

Beberapa pilihan setting

SET,,OSC,19999991
SET,,OSC,19999990
SET,,OSC,19999989
STE

Scan Ulang Frekuensi

Hasilnya harus lebih baik

cd /usr/local/src/kal-v0.4.1/src
./kal -s 900 -F 52000000 -b GSM900 -vv

Semoga hasilnya memperoleh offset yang lebih baik, seperti

FPGA clock : 52000000
Decimation : 192
Sample rate: 270833.343750
kal: Scanning for GSM-900 base stations.
channel detect threshold: 6922.106769
GSM-900:
	chan: 36 (942.2MHz -  34Hz)	power: 192896.03
	chan: 37 (942.4MHz -  30Hz)	power: 48710.69
	chan: 38 (942.6MHz -  13Hz)	power: 31109.57
	chan: 64 (947.8MHz +  68Hz)	power: 15319.56
	chan: 66 (948.2MHz +  65Hz)	power: 14363.92
	chan: 109 (956.8MHz +   2Hz)	power: 12547.61
	chan: 112 (957.4MHz -  88Hz)	power: 10748.52
	chan: 113 (957.6MHz +  42Hz)	power: 22609.95
	chan: 114 (957.8MHz +  36Hz)	power: 18037.21
	chan: 115 (958.0MHz +  61Hz)	power: 15508.45
	chan: 116 (958.2MHz +  80Hz)	power: 10971.88
	chan: 119 (958.8MHz +  65Hz)	power: 24555.23
	chan: 123 (959.6MHz +  25Hz)	power: 16705.38

Referensi

Pranala Menarik

Persiapan

OpenBTS 2.6

OpenBTS 2.8

Multi OpenBTS 2.8

Ettus E110

GPRS

Power Amplifier

Lain Lain

Catatan Legal dan Pendukung

Catatan Sejarah

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