PCU Debugging for Field Engineers

8/3/2019 PCU Debugging for Field Engineers

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GSD Quality of Service OperationSystem Performance Group Vienna

PCU logging

for field engineers

Author/Editor:

Ulrich [email protected]

Motorola GSD - Quality of Service OperationSystem Performance Group Vienna

Date: 07 December 2011

Document ID: UG-01-01-01Document version: 0.1

Status: draft

Find the newest version of this document in: http://compass.mot.com/go/spg

Abstract:Due to lack of official supported statistics and benchmarking tools, it is for specific purposesnecessary to log PCU internal messages.This document describes useful commands and procedures solely to benchmark a GPRSsystem as part of the end-to-end optimization service, including very basic procedures aswell as practical tips and tricks. The document does not provide any troubleshootingprocedures.

Motorola Confidential Proprietary

This document and the information contained in it is CONFIDENTIAL INFORMATION of Motorola, and shall not be used, published, disclosed,or disseminated outside Motorola in whole or in part without Motorolas consent. This document contains trade secrets of Motorola. Reverse

engineering of any or all of the information in this document is prohibited. The copyright notice does not imply publication of the document
http://compass.mot.com/go/spghttp://compass.mot.com/go/spg


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End2end optimisation PCU internal stats

SIGN-OFF FORM

Author Ulrich Gross signature Date

Revised signature Date

Revised signature Date

HISTORY OF REVISIONS

Revision Date Author Revised by Changes Description

0.1 draft

0.2 internal review

1.0 released

System Performance Group Vienna Page 2/18Motorola Confidential Proprietary


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Table of Content

..................................................................................................................................................21. General...................................................................................................................................4

1.1. A peek inside the PCU .................................................................................................... 41.2. How to ..........................................................................................................................5

1.2.1. login to a PCU ...................................................................................................... 51.2.2. .. display cell to PRP mapping .............................................................................. 51.2.3. .. disable security timeouts ...................................................................................61.2.4. .. enable/disable Timestamp .................................................................................61.2.5. .. enable/disable filters .......................................................................................... 61.2.6. .. know which PICP terminates which link ............................................................ 71.2.7. . Check LCI to CID mapping ................................................................................. 71.2.8. How to set the baud rate of the on board serial interface ........................................7

2. BLER & CS .............................................................................................................................83. TBF set up and termination ....................................................................................................9

3.1. TBF filter .......................................................................................................................... 93.2. Watch TLLI.................................................................................................................... 10

4. GBL ...................................................................................................................................... 104.1. UL/DL traffic ................................................................................................................... 104.2. PCU flow control buffer ................................................................................................ 11

Appendix A. Short Command reference .................................................................................. 12Appendix B. Copy of PCU_Logging_Guide ...........................................................................13Appendix C. Uplink Power Control........................................................................................... 14Collecting logs ..........................................................................................................................15PRM SLLD V3.03 ..................................................................................................................... 15Section 2.6.1.1 Closed Loop Power Control............................................................................ 15ETSI 5.08 10.2.1 ...................................................................................................................... 16MS output power ...................................................................................................................... 16ETSI 5.05:................................................................................................................................ 174.1.1 Mobile Station ................................................................................................................. 17References ............................................................................................................................... 18

Table of Figures



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1. General

1.1. A peek inside the PCU

G b i n p u t

u f f e r

( p e r P R P

U L S t a t um e s s a g e s

G T M

G R

U L G b f ra m

U L G b f r a m e s

F R a n dS T R E A M

D L G b f ra m

P I C P- G b ( P P C 7 5 0

H D L C

D r i v e r

E 1

E 1

F R D L S P

F l o w C o n t r

a n d F l u s h

s i g n a l

F R A P I m e s s ag

F R f r a m e s

P P C 8 6

P S P ( P P C 7 5 0 b o a

P IC P-TR A U

( 1 /2 o f a P P C 8

P R P ( P P C 7 5 0 b o

E X E CD L S P

G W

G B M

C C T X

T S N

F B

P P G M

D L SP R M

(1 / 4 o f a P P C 7

S t a t

C C R X

E x e c u t e s o nP P C 7 5 0 E x e cu te s o n P PCPa r t o f a m u l t i p r o c e s s f u n

n i t b u t i s a s e p a r a t e pK e y :

o n E 1

G S L( 1 o r m o r e 6L A P D l i n k

D L G b s i g n a l in

P a g e s f o r

P C C C H / P A C C

C e l l

A c t i v a t i o n

D e a c t i v a t i

G bl i n k s t a t

c h a n g e s

R A C H F lo w

C o n t r o l R e q

I m m e d i a t e A s s i

D o w n l in k T R A U f

U p l i n kT R A U f ra

R L Cl o c k s

C e l l s t a t u

c h a n g e s

R L C

l o c k s

G S L

m e s s a

C e l l s t a t u s c h a n

D B N o t i f i c a t i o n F l o w C o n t r b u f f e r (per c el l ,p e r Q o

P a g i n

b u f f e r ( p e r c e l lp e r p a gg r o u p

S y s i n f b u f f e r ( p e r c e l

T i m i n g d a t a , s y n c s

U L C

C P G M P a g e s f o r C C C

N S TD L T e s t P D

T o G B M :

N o t i f i c a t i

m e s s a g e s

D L B S S G P f ra

U L G b f ra m e

U L T e s t P D

S Y M

U L G b S i g n a l

1 6 K c i r c uP CU-CC U

P a g e s f o r C C C

G S L

F l o w C o n t r o l

P D U s

L A P D

F r a m e

C B

Figure 1:

PCU block diagram

As far as performance is related, PRM, FBM, GR and GTM are of interest as they handledirectly data blocks.PRM: Packet resource managerResponsible for air interface resources, so if one needs info regarding RLC blocks, TBFs,CS selection and similar stuff, he needs to ask PRM.FBM: Flow buffer managerIf anything related to flow control is suspicious (especially when dealing with non MotorolaSGSN) its always worth having a look at what FBM has to say. Gives info about the PCUbuffer level and leak rate, instantaneous and as reported to the SGSN.


PRM


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GR/ GTM: Gb Router /Gb transmit manager, responsible for handling LLC frames comingfrom and going to the Gb link. Thus, if no Gb link analyser is available, info dumped by thosetwo can be used to count LLC frames, check for throughput peaks on the Gb, etc.

1.2. How to

1.2.1. login to a PCU

There are three ways of logging into a PCU, all of them with different characteristics:1) Via OMC

The most common way in the field, although not the most preferable. Either use thetty_rlogin function from the OMC-R GUI, or the command tty_rlogin

2) Via tty over the BSCThis is the least preferable option as it has the disadvantage of having to be at the sitebut still being restricted to 9600 Baud. Simply plug a terminal to the MPROC serial

interface.

3) Via tty directly on the processor card of the PCUThe best one can do as the serial interface can do 57600 Baud Disadvantage: Aspecial cable is necessary.Want to order a kit of all kinds of cables? This is the ordering number:

To login:MMI-RAM 0114 -> chg_lMMI-RAM 0114 -> set_mmi exec_monSET_MMI was successfulGPROC2_RAM:emon_0114 %

GPROC2_RAM:emon_0114 % rl 2541106hPCU:emon_1106 %

254 points at the PCU and 1106h to the processor board to login. In this case it is aPRP in slot number 6.

If you are using a direct terminal connection, set_mmi wont work, use instead.

To logout: to log out of the PCU card

MMI-RAM 0114 -> !logout to log out of the BSC

******* IMPORTANT NOTE*******Due to the low data rate logs might get corrupted when there are too many messagescoming. This means, that one has to consider always the possibility that a particularmessage might have been lost.

***************************************

1.2.2. .. display cell to PRP mapping

Login to the PSP (must be slot 7 or 9) Chg_l



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msg_s 0d0h 9000h 0 0 0 9

Example output:CPU ID Local Cell Ids

------ --------------------------------------------------------------------0x1103 0xd 0 0x3 0x6 0x8 0x9 0xc 0x11 0x12 0x15 0x17 0x1b 0x1e

0x25 0x3b 0x3c 0x3f 0x45 0x4b 0x4e 0x510x1104 0x1 0x7 0xa 0x13 0x16 0x24 0x26 0x2a 0x2b 0x2c 0x2e 0x34 0x35

0x36 0x38 0x3a 0x3d 0x40 0x43 0x49 0x4c 0x4f0x1105 0x14 0x18 0x19 0x1a 0x1d 0x1f 0x20 0x21 0x23 0x27 0x29 0x2d

0x2f 0x30 0x31 0x32 0x33 0x46 0x48 0x520x1106 0x2 0x4 0x5 0xb 0xe 0xf 0x10 0x1c 0x22 0x28 0x37 0x39 0x3e

0x41 0x42 0x44 0x47 0x4a 0x4d 0x50

NOTE: 0x indicates that these numbers are in hexadecimal format.

1.2.3. .. disable security timeouts

PCU Login to the card of desire chg_l msg_s 23 1 0 0 8a04h 1 The DPROC should come back with:

PCU:emon_1105 % Disabling security time out

BSCAt the emon prompt:

msg_s 112 6 0 0 1c00h 1 No feedback

1.2.4. .. enable/disable Timestamp

time_stamp on/off

1.2.5. .. enable/disable filters

the commandiir_mod

instructs the PCU to show debug messages of that specific process.

To turn the filter off simply set the filter bitmap to 0.

****** PRACTICAL TIP ******When a filter dumps a lot of messages, its often hard to issue the commands as its notpossible to see the echo or the feedback of it. To make things easier, prepare thecommands to use in a text file and just paste them to the terminal.

************

****** NOTE ******Filter output might change from BSS software version to another.

************



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1.2.6. .. know which PICP terminates which link

On the mmi of the BSS type:Disp_proc pcu

Example output:MMI-RAM 0115 -> disp_proc pcu

PROCESSOR STATUS INFORMATION FOR LOCATION PCU:OPER STATES: D:Disabled E:Enabled B:BusyADMIN STATES: L:Locked U:Unlocked E:Equipped NE:Not Equipped

NC: Not ConnectedRelated Related

CPU# Processor Name State Reason Device Function---- ---------------------- ----- ------------------------- ----------- --------1107 PSP 0 0 B-U NO REASON N/A N/A1101 DPROC (PICP) 1 0 B-U NO REASON MSI 0 0 N/A

GDS 0 0 N/AGSL 0 0 N/AMSI 1 0 N/AGBL 0 0 N/A

(GDS 3 0) N/A(GDS 2 0) N/A

1102 DPROC (PICP) 2 0 B-U NO REASON MSI 2 0 N/AGDS 1 0 N/AGSL 1 0 N/AMSI 3 0 N/AGBL 1 0 N/A

(GDS 5 0) N/A(GDS 4 0) N/A

1103 DPROC (PRP) 3 0 B-U NO REASON MSI 4 0 N/AGDS 2 0 N/A




END OF STATUS REPORT

This tells you that PRP 3 is physically terminating GDS 2 0, but PICP 1 is handling it. GBL 1is terminated at PICP 2 so you need to log into this card to trace GBL messages for BVCIson GBL 1.

1.2.7. . Check LCI to CID mapping

MMI-RAM 0115 -> disp_gsm_cells

1.2.8. How to set the baud rate of the on board serial interface

PCU:emon_1106 % baud (easy, eh?)



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2. BLER & CS

The CS selection algorithm reports a series of information regarding the quality of the airinterface. In fact it is the output of the CS selection algorithm containing all the information

the algorithm uses to determine which CS to use.NOTE: It reports for each MS in all the cells served by the PRP!! Be careful when using, thismeans a flood of messages and the probability of losing messages is raised!On the PRP serving the cell under investigation:

PCU:emon_1106 % iir_mod 0d9h 4200h

Example filter outputTLLI:e0c492d7 DL CS2=>CS2 BLER:0.000000 ULABN:252201 PIF penalty: 0 PifABN: 4294967295Score: 0 Stall: 0 Missed DAK: 0 PIF 0 BLER: 0.000000DLACK: TLLI: e0c492d7 Cell 068 TX Max 043 Adj 043 Min 001 CalcC 041 CalcBL 041 Stal 000 RawC -51 RxQ 000 Bler Calc 0.000 Prev0.000 PPrev 0.000 DesP 043 AtnC 000 AtnP 000 Plat 10 CAdj -51 CS 001 ts 006 p_redu 000Poll cs map : 252213 CS: 1 ftype :1

Staying in phase 5BLER UPDATE: Tot:4 NK:0 BL0.000000=> 0 at ULABN: 252203Score: 0 Stall: 0 Missed DAK: 0 PIF 0 BLER: 0.000000calc carrier level is -51, RxQual is 000, New Pwr level (dBm) is:041, Prev DL Pwr level 43Enforcing SMG29 No Power Control ModeCurrent dl ts alloc is f0 (Hex)dl attn[0] = 255, [1] = 255, [2] = 255, [3] = 255, [4] = 0, [5] = 0, [6] = 0, [7] = 0

TLLI: Indicates the mobiles TLLI CSX=>CSY: Indicates if the CS changes, or stays the same. BLER: The result of a calculation of the BLER over the last 128 blocks. Note: BLER

will stay 0 if the CS changes before the 128 blcok count are reached. In that casethere must be missed DAKs or stalls instead.

Missed DAKs: Indicates the number of missek DL acknowledge messages. Thenumber displayed represents the actual number of missed DACKs weighted with afactor (5 in 16.20.e1-t5).

Stall: Indicates number of RLC window stalls occurred, again weighted with a factor(10 in 16.20.e1-t5).

ULABN: UL Absolute Block Number each Block 20ms => accurate timestamp Cell: Indicates the cell by the Local Cell ID RawC: The C value reported by the mobile. Current TS allocation: Refers to the DL and represents a bit pattern in Hex format.

E.g.: f0h = 11110000b this would mean TS 7,6,5,4 for DL

****** NOTE ******If you want to synchronise with a drive tester during logging, keep in mind that there is abuffer for the serial interface. This will effectively delay the messages for a couple ofseconds.

*********************Tips for post processingDue to the fact that BLER is calculated on a base of 128 blocks (16.20.e1-t5) it might well bethe case, that the number of valid BLER reports is very low, as it will always show 0 if itdoesnt have a valid measurement. This implicates, that a BLER distribution taken out of thethis filter output cannot come alone, but has to come along preferably in the same chart withmissed DAKs, stalls and CS distribution.



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3. TBF set up and termination

3.1. TBF filter

This filter reports messages regarding TBF setup and termination for each TLLI handled bythe particular PRP. TBFs are handled by the Packet Resource Manager (PRM) whichalways has the process id d9h.NOTE:It reports for each MS in all the cells served by the PRP!! Be careful when using, this meansa flood of messages and the probability of losing messages is raised!

On the PRP serving the cell under investigation:

PCU:emon_1106 % iir_mod 0d9h 0c0000000h

Example filter outputTLLI c4861ca8: received PRRon (68,1,4) at ulabn:239962 race=0Sending TLLI c4861ca8 TFI: 24 PUA( a) on (68,1,4) at abn = 239971, curr_dl_abn239971 or 54536370 ms, rrbp = 0

TLLI c4861ca8 UL tfi = 24 starting on (68,1,7) at 239974TX Watch: Receiving TLLI 0xc4861ca8, cell 68, tx_buffer_index = 0 num_blocks(CS1) = 2Sending TLLI c4861ca8 TFI: 16 PTR( 7) on (68,1,7) at abn = 239987, curr_dl_abn239987 or 54536690 ms, rrbp = 3TLLI c4861ca8 DL tfi = 16 starting on (68,1,7) at 239993TLLI c4861ca8 DL tfi = 16 starting on (68,1,5) at 239993TLLI c4861ca8 UL tfi = 24 starting on (68,1,6) at 239993TLLI c4861ca8 DL tfi = 16 starting on (68,1,6) at 23999354537130 TLLI c4861ca8 UL tfi=24 normal_tbf_release at ulabn=240001 stats(1 1 1)DL TBF( 16): uplink requested in DAK for TLLI: c4861ca8 at ulabn = 240003Sending TLLI c4861ca8 TFI: 25 PUA ( a) on (68,1,6) at abn = 240011, curr_dl_abn240011 or 54537170 ms, rrbp = 0

TLLI c4861ca8 UL tfi = 25 starting on (68,1,6) at 24001454537610 TLLI c4861ca8 UL tfi=25 normal_tbf_release at ulabn=240025 stats(1 1 1)54541890 :TLLI c4861ca8 DL tfi=16 normal_tbf_release at ulabn=240239 stats(64221 0 80 743)

PRR Packet Resource Request PTR Packet Timeslot Reconfigure TFI Temporary Flow Indicator

PUA Packet UL Assignment Starting on (LCI,carrier id,TS)

Stats:

for UL total new blocks, total missed blocks, total received blocks.for DL total idle blocks, total new blocks, total NAK blocks, total PAK blocks, sum of all.

TIPSIf you want to look at a particular TLLI, be careful to catch the start of the transmission.Otherwise due to supercoattail you might never see the DL assignment.



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3.2. Watch TLLI

This function is useful if you need detailed information about a specific mobile, e.g. toenhance the information given by MDTT with the PCU info.

NOTE: It`s not recommended to enable it globally outside a lab system. In the field it can bevery useful, but only if its enabled for the TLLI under investigation.

msg_s 0d9h 9000h 0 0 7404 4 34 1

Example: msg_s 0d9h 9000h 0 0 7404 4 34 1 0ch 0 0c3h 0f8hwill enable watch tlli for tlli = c00c3f8h

msg_s 0d9h 9000h 0 0 7404 4 34 0 will turn it off,msg_s 0d9h 9000h 0 0 7404 4 34 0ffh will turn it on globally.

Example outputTLLI c886894e ul request in new cell 28 from old cell 71tlli = c886894e, ms class = 4. freq_type 1Picking tfi index:0:rx buff index:0:old_index_in the map:35 for TFI:13Created TFI:13, tfi index: 0, rx buff index:0UL TBF( 13) starting at frame= 479015, abn= 110542, rbn= 10, num_dl_msg = 1Sending TLLI c886894e TFI: 13 PUA( a) on (28,1,4) at abn = 110539, curr_dl_abn110539 or 51650802 ms, rrbp = 0

Sending TLLI c886894e TFI: 13 PUA ( a) on (28,1,4) at abn = 110560, curr_dl_abn110560 or 51651223 ms, rrbp = 0

tlli c886894e ul_tfi 13 resend PUA with no PCA at (28,1,7) missed 6 data blocksSending TLLI c886894e TFI: 13 PUA ( a) on (28,1,4) at abn = 110575, curr_dl_abn 110575or 51651523 ms, rrbp = 0tlli c886894e ul_tfi 13 resend PUA with no PCAat (28,1,7) missed 18 data blocksNo UD received (25 blocks): TLLI: c886894e TFI: 13

No UD received (25 blocks): TLLI: c886894e TFI: 13No UD received (25 blocks): TLLI: c886894e TFI: 13TLLI c886894e ul_tfi 13 1st uplink data block at (28,1,7) ul_state TRANSFER mc_stateTRANSFER ulabn 110663TLLI c886894ebsn at countdown 0 = 0 ulabn = 110663TLLI c886894e final bsn 0, ulct_end = 110688, ulabn = 110663

TLLI Packet UL Assignment Packet Control Acknowledge (LCI, carrier id, TS) relative reserved block period

block sequence number

4. GBL

4.1. UL/DL traffic

The GBL is terminated at the PICP. The processes handling incoming/outgoing traffic are Gbrouter (GR), process id 0d7h for DL and GTM process id 0d3h for UL.

PCU:emon_1101 % iir_mod 0d7h 0f8hiir_mod: iir_mask for process 0xd7 changed to 0x000000f8.PCU:emon_1101 % iir_mod 0d3h 0fchiir_mod: iir_mask for process 0xd3 changed to 0x000000fc.



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052432535ms: FLOW_CONTROL_BVC_ACK PDU received on BVCI 2271452435943ms: DL_UNITDATA PDU received. BVCI 30104, LLC len: 25, TLLI: 0xc4835a8aSUSPEND_ACK PDU received for TLLI C0860ABC52442165ms : UL_UNITDATA PDU sent. BVCI 30104, PDU len: 1611, TLLI: 0xc4835b04, PRP:0x1106

52442213ms: DL_UNITDATA PDU received. BVCI 30104, LLC len: 25, TLLI: 0xc4835a8aSUSPEND_ACK PDU received for TLLI C4835B04FLOW_CONTROL_BVC_ACK PDU received on BVCI 22714FLOW_CONTROL_BVC_ACK PDU received on BVCI 2271452457641ms : UL_UNITDATA PDU sent. BVCI 23704, PDU len: 1611, TLLI: 0xf1031774, PRP:0x1104

BVCI identifies also the cell LLC len: length of the LLC frame TLLI PDU len: reports always 1611, this is a bug.

4.2. PCU flow control buffer

The PCU buffer, (the leaky bucket) is handled by the Flow Buffer Manager (FBM). Especiallywhen the SGSN is non Motorola and the track leads to a flow control issue this filter will givevaluable info additionally to Gb logs as it not only reports what the PCU sends to SGSN, butalso the real situation in the PCU buffer.

To activate: iir_mod 0d5h 0f000h

Example output53872703 CELL 5 CBL: 0 BMAX: 140625 R: 450 decr53877975 CELL 5 FBM is initializing the rate buffer53882220 CELL 28 CBL: 18 BMAX: 151875 R: 486 incr53882220 CELL 28 CBL: 0 BMAX: 151875 R: 486 decr53887460 CELL 28 FBM is initializing the rate buffer53910137 CELL 83 FBM is sending fc with Bmax= 103700 and R= 33253997059 CELL 83 FBM is sending fc with Bmax= 120000 and R= 38453999710 CELL 14 CBL: 18 BMAX: 145000 R: 464 incr53999710 CELL 14 CBL: 0 BMAX: 145000 R: 464 decr54002699 CELL 83 FBM is sending fc with Bmax= 145300 and R= 465

Current Buffer Level BMAX maximum allowed buffer level. This is dynamically allocated by the PCU,

depending on the number of cells handled by the PRP

fc actual flow control message sent to the SGSN timestamp in milliseconds



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Appendix A. Short Command referenceTo set watch tlliglobally (PRP)msg_s 0d9h 9000h 0 0 7404 4 34 0ffh

To set watch tlli fro a specific tllimsg_s 0d9h 9000h 0 0 7404 4 34 1 examplemsg_s 0d9h 9000h 0 0 7404 4 34 1 0ch 0 0c3h 0f8h

* should produce* watch tlli enabled for tlli = c00c3f8h

To turn watch tlli offmsg_s 0d9h 9000h 0 0 7404 4 34 0

To print DL BLER and CS used on PRP.iir_mod 0d9h 04200h

To force CS on the PCU (PRP):msg_send 0d9h 9000h 0 0 7404h 4 47

Where is: 0 = force CS1, 1 = force CS2,If allow_32_k_trau=yes2 = force CS3, 3 = force CS4

255 = algorithm selectWhere is: 0 = force CS1, 1 = force CS2,

If allow_32_k_trau=yes2 = force CS3, 3 = force CS4

255 = algorithm select

To print CS flags (PRP):msg_send 0d9h 9000h 0 0 7404h 4 48

To print DL LLC frame info of PICP:iir_mod 0d7h 0f8h

To print UL LLC info of PICP:iir_mod 0d3h 0fch

To print filters:iir_dis

To print TBF information of PRP:iir_mod 0d9h 0c0000000h

To print PCU buffer information of PRP:iir_mod 0d5h



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Appendix B. Copy of PCU_Logging_Guide

Enable logging on the PCU via OMC-R remote access to the proper PCUcard

To Do:1. disable security timeout value on OMC-R or take care that it doesnt time out (30

minutes)2. remote login to BSC MMI3. look up local cell id: enter disp_gsm_cell 4. change to security level 35. set_mmi exec_mon (go to GPROC) or Cntrl-N

6. disable security timeout on GPROC: msg_send 112 6 0 0 1c00h 17. rlogin to PCU MPROC: rl 254 1107h8. to figure out the port hosting cell with local cell id from above: route logical 149. go back to the GPROC with Cntrl-D10.rl 254 1111.change to security level 312.disable secutiry timeout on DPROC: msg_s 23 1 0 0 8a04h 113.time_stamp on14.dump the information reported after entering: iir_m 0d9h 0c0004000h

... CS and TBF information15.to disable the logging and close the session: iir_m 0d9h 0

16.17.

Result Step 8:OFFSET CPU MBOX OFFSET CPU MBOX OFFSET CPU MBOX---------------------- ---------------------- ----------------------1 0x1106 ------........1 is our local cell id and it is hosted on card 1106



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Appendix C. Uplink Power Control

V1.0 RAN 2/11/03 Updated to reference other docs.

See PRM LLD, ETSI 5.05, ETSI 5.08 for further detail.

Closed Loop Power Control: Calculation of ms_pwr_offset fudge factor.

We want to vary the MS power offset according to how far away the BTS RxLev is from the power box mean.

Pbm = pwr_box_mean

Pbm_rxlev_diff = rxlev_bts pwr_box_mean.

CH = rxlev_bts pwr_box_mean ms_pwr_offset

CH = pbm_rxlev_diff ms_pwr_offset

CH can vary in the range of gamma_0_offset (6) max_gamma (62) max_gamma will always = 62.

Therefore ms_pwr_offset can range between 0 CH pbm_rxlev_diffi.e. 0 62 pbm_rxlev_diff

This variation is CH should correspond to mobiles transmit capability variation i.e. max_ms_tx_pwr (33) min_ms_tx_pwr (5) = ms_tx_pwr_range (28)

Setting ms_pwr_offset to max will then correspond to incrementing/decrementing the ms_tx_power by max ofms_tx_pwr_range (28).

ms_txpwr_range won't be 28 always. The value depends on the min_tx_power and max_tx_power.Former depends on the freq band (GSM900, DCS1800) and later depends on the freq band and MSRAcapability of the mobile. So the range would depend on which mobile you are using in which freq band.

[62 pbm_rxlev_diff] max_tx_pwr_range

Therefore,

Ms_pwr_offset =

(pbm_rxlev_diff * max_tx_pwr_range)

[max_gamma pbm_rxlev_diff]

Need to kick mobile harder if pathloss doesnt vary and RxLev is still outside the power box.

Example of Field Log:

Out of Pwr Box, TLLI:c0000e88:ul_abn:202008:PrevGamma:6:NewGamma:6:ul_rxlev:-82:ms_pwr_offset:5:ts:3:multiplier:-1TLLI:0xc0000e88:ul_gamma sent in PCTA:3:TS:3TLLI:0xc0000e88:ul_gamma sent in PCTA:14:TS:7Out of Pwr Box, TLLI:c0000e88:ul_abn:202014:PrevGamma:6:NewGamma:6:ul_rxlev:-84:



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ms_pwr_offset:4:ts:3:multiplier:-1

Explanation: The value that is actually sent to the MS is in the ul_gamma sent line and it indicates which message it

was sent in. It also indicates which timeslot the ul_gamma was sent for. In this case, the POWER BOX (ie where we want to keep the mobile) is set to: l_rxlev_ul_p = 30 (-80 dbm) u_rxlev_ul_p = 40 (-70 dbm) so we want to try to keep the MS transmitting at a power such that our RXLEV that we receive is ~-75dbm gprs_pc_alpha = 0 in this example (Close loop which is recommended). With this setting, we tell the MS which

absolute power to transmit at. In GSM900, the max power that the MS can transmit is 39dbm see below. For a 2W mobile, the MS is

capable of transmitting at a maximum of 33dbm. Therefore with the power control formula below, if the PCUwants the 2W MS to transmit at maximum power, it will send a gamma = 3 for the timeslot which tells the MSto transmit at 6dbs below 39dbm (or 33dbm).

In GSR5x the PCU might send a gamma for two separate timeslots even in the case where only a ULsingle timeslot is active. This could happen when mobile just ended an UL (on TS 7) and started a newUL (on TS 3). We retain gamma for TS 7 if the previous UL were released normally. So we will havegamma values for two TS's available and we would send both to mobile in the PUA assignment. InPUAN however we send it only for the TS assigned for current UL TBF.

In 1650 the PCU sends gamma only for the TS assigned on current TBF for PUA as well as PUAN. For PCTR we never send an altered gamma value. We always tell the mobile to go full power on the new TS

assigned.

GAMMA_TN (5 bit field)The GAMMA_TN field is the binary representation of the parameterCH for MS output power controlin units of 2 dB, see 3GPP TS 05.08. The GAMMA_TN field is coded according to the following table:

Bit5 4 3 2 10 0 0 0 0 CH = 0 dB0 0 0 0 1 CH = 2 dB: : : :1 1 1 1 0 CH = 60 dB1 1 1 1 1 CH = 62 dB

Collecting logs

- UL RXLEV should be between the cell parameters u_rxlev_ul_p and l_rxlev_ul_p for the majority of

the run if all is working well and you should see In Power Box and not Out of Power Box:- iir_m 0d9h 0c0000000h- TLLI watch- msg_send 0d9h 9000h 0 0 7404h 4 255 1 00 00 01 00 (power control)

PRM SLLD V3.03

Section 2.6.1.1 Closed Loop Power ControlClosed loop power control can be achieved by setting to zero and becomes an algorithm very similar

to that used in circuit switched power control. When this algorithm is used, the PCU effectively sendsthe mobile station the actual attenuation off maximum power, (CH) to transmit at. The mobile stationuses the following equation to determine the power level to transmit at:



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CHP = 0

Where 0 is a constant that depends on the frequency band that the mobile is operating within.0 = 39 dBm for GSM9000 = 36 dBm for DCS1800

0 = 33 dBm for PCS 1900 0 = 39 dBm for GSM850

The base station then uses the receive level of the base station on each channel (SS b) in conjunctionwith the power box mean to determine the new attenuation level to be used. If the mobile is within thepower box, no adjustment is necessary. If the mobile is outside of the power box then CH is adjustedaccordingly and stored in the mobile context for the next opportunity to send power control informationto the mobile.The Following Equations are used:

=

2

______ PU LR X L E VLPU LR X L E VUP w r B o x M e a n

If ((SSb +18) > U_RXLEV_UL_P)

( )2

18Re PwrBoxMeanSS

bCH duction +=

If ((SSb +18) < L_RXLEV_UL_P)

( )2

18+=

b

CH

SSPwrBoxMeanIncrease

SSb: 0 = -128dBm L_RXLEV_UL_P: 0 = -110 dBm1 = -127 dBm and U_RXLEV_UL_P 1 = -109 dBm 127 = -1 dBm 63 = -47 dBm

Open Loop Power Control

ETSI 5.08 10.2.1

MS output powerThe RF output power, PCH , to be employed by the MS on each individual uplink PDCH shall be:

PCH = min(0 - CH - * (C + 48), PMAX), (1)

where

CH is an MS and channel specific power control parameter, sent to the MS inan RLC control message (see 3GPP TS 04.60). For those uplink PDCHs, for

which CHhas not been defined, value 0 shall be used.

0 = 39 dBm for GSM 400, GSM900, GSM850= 36 dBm for DCS1 800 and PCS 1900

is a system parameter, broadcast on PBCCH or optionally sent to MS in anRLC control message (see 3GPP TS 04.18 and 3GPP TS 04.60).

C is the normalised received signal level at the MS as defined in 10.2.3.1.

PMAX is the maximum allowed output power in the cell =GPRS_MS_TXPWR_MAX_CCH if PBCCH or CPBCCH existMS_TXPWR_MAX_CCH otherwise

All power values are expressed in dBm.When the MS receives new CH or values, the MS shall use the new value to update PCH according toequation (1) 2 radio blocks after the end of the frame containing the last timeslot of the message block



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containing the new value, which ensures 2 blocks time for processing even in case of timeslotreconfiguration.The MS may round the calculated output power to the nearest nominal output power value (see 3GPPTS 05.05) although a higher resolution is preferred. The output power actually transmitted by the MS

shall fulfil the absolute accuracy as specified in 05.05. In addition, the transmitted power shall be amonotonic function of the calculated output power and any change of 2 dB in the calculated value shallcorrespond to a change of 2 1.5 dB in the transmitted value.The MS shall use the same output power on all four bursts within one radio block.When accessing a cell on the PRACH or RACH (random access) and before receiving the first powercontrol parameters during packet transfer on PDCH, the MS shall use the output power defined byPMAX.

MS_TXPWR_MAX_CCH is broadcast on the BCCH of the cell. A class 3 DCS1 800 MS shall add to itthe value POWER OFFSET broadcast on the BCCH.GPRS_MS_TXPWR_MAX_CCH is broadcast on PBCCH or CPBCCH of the serving cell.If the MS accesses a cell on the PRACH before receiving GPRS_MS_TXPWR_MAX_CCH on PBCCH,the MS shall determine PMAX using MS_TXPWR_MAX_CCH as default.If a calculated output power is not supported by the MS, the MS shall use the supported output powerwhich is closest to the calculated output power.

ETSI 5.05:

4.1.1 Mobile StationThe MS maximum output power and lowest power control level shall be, according to its class, asdefined in the following tables (see also 3GPP TS 02.06).For GMSK modulation

Power GSM 400 & GSM 900 &GSM 850

DCS 1 800 PCS 1 900 Tolerance (dB)

class Nominal Maximumoutput

Nominal Maximumoutput

Nominal Maximumoutput

for conditions

power power power normal extreme1 - - - - - - 1 W (30 dBm) 1 W (30 dBm) 2 2,52 8 W (39 dBm) 0,25 W (24 dBm) 0,25 W (24 dBm) 2 2,53 5 W (37 dBm) 4 W (36 dBm) 2 W (33 dBm) 2 2,54 2 W (33 dBm) 2 2,55 0,8 W (29 dBm) 2 2,5



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References

[1] PRM_Low_level_design[2] ETSI GSM05.03


Date post:	06-Apr-2018
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