- This topic has 7 replies, 1 voice, and was last updated 12 years, 1 month ago by Pix.
14th March 2009 at 22:49 #56193ISTGuest
in tems while analyzing drivetest log files, we found that for some HO failures the RR message sequence was as below:
HO Command (sent from BS)->HO failure (sent by MS)
and the time difference between the HO command received my MS and the HO failure sent by MS was less then 1 ms.(i.e. just after getting the HO command, MS sent HO failure instantly).
What is the reason for that? Can any 1 help please?15th March 2009 at 07:24 #56194PixGuest
very interesting ! i would suspect the MS is not happy with the content of the HO Command –> basically, the HO CMD is describing the target cell, and the MS, while reading it, feels like this neighbor cell is not suitable for himself. Wrong frequency range ? Wrong codec ? Wrong ciphering mode ?
Pix15th March 2009 at 10:52 #56195ISTGuest
in the case of wong frequency range or wrong codec, the cause for HO failure should be like “frequency not implemented” or “channel mode unacceptable” as I saw it from ETSI.
But in our case its always the same cause “Protocol error unspecified”..(cause value: 111).
And the interesting thing is ,MS was reacting instantly..no time delay between HO command and HO failure.15th March 2009 at 22:21 #56196RexGuest
is that happening randomly or just in one HO relation, randomly in all HO relations in one BSC or HO relations between two BSCs? It’s probably MSC problem. Check NSS!16th March 2009 at 04:46 #56197PixGuest
Well, i couldn’t know that, since you didn’t say anything in your 1st post 🙂
The mobile reads the HO CMD message and replies with a HO failure. I understand your issue with the MS timing : 1ms is rather fast. However, we must assume the MS is reading and processing this particular msg with more priority than the others, so it’s not surprising.
In my opinion, there’s something in the HO CMD which is wrong, from the point of view of this TEMS mobile. Don’t you agree with this ? When you check QoS indicators in the cell, are there a lot of HO execution failure rate ? (lots of request, lots of attempts, but little success?)
Could you copy & paste the full content of this ho cmd msg here please ?16th March 2009 at 21:21 #56198ISTGuest
below HO command copy and past:
Frame number: 4833242
Skip indicator : 0
Protocol discriminator : (6) Radio resources management messages
Message type : 43
BSIC : 3-0
BCCH ARFCN : 26
Description of the first channel, after time
Channel type : (1) TCH/F + ACCHs
Timeslot number (TN) : 1
Training sequence code (TSC) : 0
Hopping RF channel : (1) RF Hopping Channel
Mobile allocation index offset (MAIO) : 1
Hopping sequence number (HSN) : 17
Handover reference value : 105
Power command and access type
Access type control (ATC) : (0) Sending of Handover Access is mandatory
Enhanced power control (EPC) : (0) Channel(s) not in EPC mode
Fast measurement reporting and power control (FPC) : (0) FPC not in use
Power level : 5
Normal cell indication : (1) Out of range timing advance shall trigger a handover failure procedure
Report observed time difference : (0) ‘Mobile Time Difference’ IE shall not be included in the Handover Complete message
Synchronization indication : (0) Non-synchronized
Frequency channel sequence, after time
Channels : 50 56 60 71 76
[0 ] : 50
[1 ] : 56
[2 ] : 60
[3 ] : 71
[4 ] : 76
Multirate speech version : (1) Adaptive Multirate speech version 1 – FR AMR, HR AMR or OHR AMR
Noice Suppression Control Bit (NSCB) : (0) Noise Suppression can be used (default)
Initial Codec Mode Indicator (ICMI) : (1) The initial codec mode is defined by the Start Mode field
Start Mode : (2) CODEC_MODE_3 (Represents the third lowest mode, if the ACS includes more than two modes)
Set of AMR codec modes
Set of AMR Codec Modes :
12.2 kbit/s codec rate is part of the subset :
10.2 kbit/s codec rate is part of the subset :
7.40 kbit/s codec rate is part of the subset :
5.15 kbit/s codec rate is part of the subset :
Threshold 1 : (14) 7.0 dB
Hysteresis 1 : (1) 0.5 dB
Threshold 2 : (21) 10.5 dB
Hysteresis 2 : (1) 0.5 dB
Threshold 3 : (26) 13.0 dB
Hysteresis 3 : (1) 0.5 dB
Header dump (Hex):
2A 00 21 00 00 00 04 21 00 03
01 00 01 1C
Message dump (Hex):
06 2B 18 1A 09 10 51 69 05 D8
69 32 64 B5 00 00 00 00 00 00
03 06 2A D2 0E 15 45 A1
hi,,,no HOSR KPI doesn’t affect too much.I mean handover success rate is ok. Actually this problem is not for a particular cell.And not related to any particular BSC.
is there any minimum time duration between the ho command and ho failure message?
in my cases there was no time duration between the ho command and ho failure.MS sent HO failure instantly at the same time it got the ho command.18th March 2009 at 08:52 #56199amanGuest
handover faiure18th March 2009 at 12:39 #56200PixGuest
Could you try deativating the AMR or the TFO ?