OpenBTS: GPRS debugging

RXGain

Kita perlu menset

GSM.Radio.RxGain

agar FER cukup baik & MS memperoleh IP address.

Masuk ke CLI.

Set

devconfig GSM.Radio.RxGain 44

Nilai default GSM.Radio.RxGain 48

Kemudian Reboot

Cek gprs list

gprs list

Pastikan FER agak lebih besar sedikit dari 0%, misalnya

 MS#1,TLLI=c000f001,7ac6f2bd rrmode=PacketIdle Bytes:86up/33down Utilization=0%
	 GMM Context: imsi=510881140050498 ptmsi=0xf001 tlli=0xc000f001 state=GmmDeregistered age=1137 idle=1137 IPs=none
	 TimingError=(-0.05 min=-0.57 max=0.54 avg=0.08 N=60) RSSI=(-53 min=-56 max=-22 avg=-50.83 N=60) CV=(63 min=55 max=63 avg=60.20 N=5) ILev=(0) RXQual=(0) SigVar=(0) ChCoding=(0)
	 dataER:.8% (78) recent:0% (0) tbfER:.2% (5)
	 rrbpER:.3% (13) recent:0% (0) ccchER:0% (1) recent:0% (0)
 MS#2,TLLI=c000f002,7f90936d rrmode=PacketIdle Bytes:12492up/24408down Utilization=0%
	 GMM Context: imsi=510105852803044 ptmsi=0xf002 tlli=0xc000f002 state=GmmRegisteredNormal age=72 idle=2 IPs=192.168.99.100
	 TimingError=(-0.21 min=-1.40 max=1.83 avg=0.21 N=2148) RSSI=(-46 min=-58 max=-9 avg=-46.08 N=2148) CV=(63 min=0 max=63 avg=61.50 N=42)
 ILev=(0) RXQual=(0 min=0 max=4 avg=0.20 N=35) SigVar=(0 min=0 max=63 avg=2.43 N=35) ChCoding=(0 min=0 max=3 avg=0.00 N=1353)
	 dataER:.4% (3426) recent:.6% (1263) low:1.0% (144) tbfER:.5% (15)
	 rrbpER:.4% (231) recent:.5% (57) low:1.0% (8) ccchER:1.0% (7)  recent:1.0% (7) low:1.0% (1)
 TBF#19  mtMS= MS#2,TLLI=c000f002,7f90936d mtDir=RLCDir::Down
	 channels: down=( 0:1 0:2 0:3) up=( 0:2,usf=0 0:3,usf=0)
	 mtState==TBFState::Dead mtAttached=1 mtTFI=19 mtTlli=0xc000f002 size=323
 TBF#20  mtMS= MS#2,TLLI=c000f002,7f90936d mtDir=RLCDir::Down
	 channels: down=( 0:1 0:2 0:3) up=( 0:2,usf=0 0:3,usf=0)
	 mtState==TBFState::DataWaiting1 mtAttached=1 mtTFI=20 mtTlli=0xc000f002 size=0
 PDCH ARFCN=620 TN=1 FER=98%
 PDCH ARFCN=620 TN=2 FER=36%
 PDCH ARFCN=620 TN=3 FER=23%

Cek sgsn list

sgsn list

Pastikan MS menperoleh IP address

 GMM Context: imsi=510881140050498 ptmsi=0xf001 tlli=0xc000f001 state=GmmDeregistered age=1222 idle=1222 MS#1,TLLI=c000f001,7ac6f2bd IPs=none

 GMM Context: imsi=510105852803044 ptmsi=0xf002 tlli=0xc000f002 state=GmmRegisteredNormal age=157 idle=9 MS#2,TLLI=c000f002,7f90936d IPs=192.168.99.100

MS 510105852803044 memperoleh IP 192.168.99.100 sementara MS 510881140050498 tidak memperoleh IP

Jika belum memuaskan, ulangi prosedur di atas. Set lagi GSM.Radio.RxGain

Jika FER sedikit di atas 0%, semoga MS memperoleh IP address.

Cek

gprs list ms -cxv

Turunkan RSSI Target

Coba

• naikan Channels.Min.C0 & TBF.Retry
• turunkan RSSI

config GPRS.Channels.Min.C0 4
config GPRS.TBF.Retry 4
devconfig GPRS.ChannelCodingControl.RSSI -60
devconfig GSM.Radio.RSSITarget -70

Kemudian Reboot

Mengatasi Tidak dialokasikan IP ke MS

Ubah konfigurasi GGSN

config GGSN.Firewall.Enable 0
config GGSN.DNS 8.8.8.8
config GGSN.DNS 8.8.8.8 8.8.4.4 (untuk 2 DNS server)

Melihat log GGSN

devconfig GGSN.Logfile.Name /tmp/GGSN.log

hasil awalnya

 18:11:06.7:Initializing Mini GGSN Wed Mar  4 18:11:06 2015

 18:11:06.7:GGSN logging to file /tmp/GGSN.log
 18:11:06.7:GGSN Configuration:
 18:11:06.7:  GGSN.MS.IP.Base=192.168.99.1
 18:11:06.7:  GGSN.MS.IP.MaxCount=254
 18:11:06.7:  GGSN.MS.IP.Route=192.168.99.0/24
 18:11:06.7:  GGSN.IP.MaxPacketSize=1520
 18:11:06.7:  GGSN.IP.ReuseTimeout=180
 18:11:06.7:  GGSN.Firewall.Enable=0
 18:11:06.7:  GGSN.IP.TossDuplicatePackets=0
 18:11:06.7:GGSN: DNS servers: 8.8.8.8 0.0.0.0
 18:11:06.7:ip link set sgsntun up 
 18:11:06.9:ip route add to 192.168.99.0/24 dev sgsntun

Menaikan Channel GPRS

OpenBTS> load

== GSM ==
SDCCH load: 0/4
TCH/F load: 0/5
AGCH/PCH load: 0,0
Paging table size: 0
Transactions: 0
T3122: 2000 ms (target 5000 ms)
== GPRS ==
current PDCHs: 2
utilization: 0%

Ada 2 PDCHs untuk GPRS, ini bisa di naikan, misalnya

config GPRS.Channels.Min.C0 5

Cek load

OpenBTS> load

== GSM ==
SDCCH load: 0/4
TCH/F load: 0/2
AGCH/PCH load: 0,0
Paging table size: 0
Transactions: 0
T3122: 2000 ms (target 5000 ms)
== GPRS ==
current PDCHs: 5
utilization: 0%

Sekarang PDCHs menjadi 5 dan TCH/F menjadi 2