Steps for Drive Test -7

Idle Drive is performed in two fashion

• Normal Drive

• Frequency Lock Drive

Normal Drive

This is done to frame the potential area of the new site planned. It also helps us to

get to know the important neighboring sites for which the handover has to take place.

Frequency Lock Drive

This is done by locking the BCCH frequency of the serving cell and performing the

drive for the same cell unless the mobile enters into No Service Mode. This is use-

ful for making decision related to GSM antenna height, tilt, and orientation.

Dedicated Drive

Dedicated drive is an important part of Drive Test. Here call is made to a test number and drive is done for the potential areas of the Site. During drive being carried out one has constantly monitor parameters such as RX Level, RX Quality, SQI, DTX, C/I Ratio, Hopping Channel, Neighbor list, TA (Timing Advance).

Steps for Drive Test -6

Intra Site Handover

Intra Handover is performed to check whether handover is taking place both ways

on the Site.

Handover is performed among all the Sectors of the Site.

Inter Site Handover

Inter Handover is performed to check whether handover is taking place both ways

on the Site with it’s adjacent neighbor. Handover needs to checked mandatorarily

for primary neighbor.

Handover is performed with all the defined neighbor's in the integration sheet.

Steps for Drive Test -5

GPRS (General Packet Radio System)

This is performed to check whether GPRS is working on the Site. This is done

by browsing a web page in browser of the phone. For GPRS to be checked it is

necessary to see that the handset is WAP, GPRS enabled.

Steps for Drive Test -4

MOC and MTC

Given are parameter need to be checked while performing MOC and MTC

RX Level (-47 dbm to -110dbm)

RX Quality (0 to 7)

SQI (20 to 30)

DTX

HSN (Hopping Sequence Number) (0 to 63)

MAIO

Hopping Frequency

C/ I Ratio (>15 dbm)

C/ A Ratio (>12 dbm)

Definition of Radio Parameters:

•RxLev : Receiving level in terms of dBm that mobile is receiving from the site. Range of -30 dBm to -110dBm.

•RxQual : Quality of voice which is measured on basis of BER. Range of RxQual 0 -7.

•FER : Frame Erasure Rate it represents the percentage of frames being dropped due to high number of non-corrected bit errors in the frame. It is indication of voice quality in network.

•BER Actual : Ratio of the number of bit errors to the total number of bits transmitted in a given time interval. BER is a measure for the voice quality in network.. Depending on BER RxQual is measured. E,g, BER 0 to 0.2 % corresponds to RxQual 0. Max. BER countable and useful is up to 12.8 % which corresponds to RxQual of max. 7.

•SQI : SQI is a more sophisticated measure which is dedicated to reflecting the quality of the speech (as opposed to radio environment conditions). This means that when optimizing the speech quality in your network, SQI is the best criterion to use. SQI is updated at 0.5 s intervals. It is computed on basis of BER and FER. For EFR 30, FR – 21 & HR – 17 are respectively ideal values.

•C/I : The carrier-over-interference ratio is the ratio between the signal strength of the current serving cell and the signal strength of undesired (interfering) signal components. It should be atleast > 9 .

•MS Power Control Level : Displays range of power control from 0 to 8 depending upon network design. E.g. 0 means no power control and 1 means level that is defined by operator viz. 2 dBm less acc. To airtel.

•

•DTX : Discontinuous transmission (DTX) is a mechanism allowing the radio transmitter to be switched off during speech pauses. This feature reduces the power consumption of the transmitter, which is important for MSs, and decreases the overall interference level on the radio channels affecting the capacity of the network..

•TA : Value that the base station calculates from access bursts and sends to the mobile station (MS) enabling the MS to advance the timing of its transmissions to the BS so as to compensate for propagation delay. Value of 0 means MS in radius of 550mt. From BS.

•RL Timeout Counter (Cur) : This parameter define the maximum value of the radio link counter expressed in SACCH blocks. Range of 4 – 64 in step size of 4. it shows current value of RLT. Decrease by 1 but increase by 2. When it reaches zero it results in normal DROP Call.

•RL Timeout Counter (MAX) : This parameter define the maximum value of the radio link counter expressed in SACCH blocks. Range of 4 – 64 in step size of 4. it shows current value of RLT. Normally 16, 20, 24.

•MS Behavior Modified : This window shows current settings for the mobile station, for instance whether handover is disabled or multiband reporting enabled.

Steps for Drive Test -3

Steps for DT-3

CPC (Cell Parameter Check)

Given are the parameters that need to be checked while performing CPC.

CGI (Cell Global Identity) consists if MCC+NCC+LAC+CI

BCCH Frequency

BSIC

GSM Band

nDefinitions:

1.Time: It is system time of computer.

2.Cell name: It displays the name of the sector which is serving according to the cellfile that is loaded in TEMS.

3.CGI : It stands for the Cell Global Identity which is unique for every sector of the site. It consists of MCC,MNC,LAC,CI.

MCC: Mobile Country Code 0 – 999 MNC: Mobile Network Code 0 – 99 LAC : Location Area Code 0 -65535 CI: Cell Identity 0 – 65535

•Cell GPRS Support: Tells sector is having GPRS or not. Values are Yes or No .

•Band : It tells in which Freq. Band mobile is operating e.g. GSM 900/ 1800.

•BCCH ARFCN: It tells by which BCCH is the mobile station getting served.

•TCH ARFCN: On which Traffic Freq. call is going on.

•BSIC (Base Station Identity Code) : It is combination of Network Color Code (NCC) (0 – 7) & Base Station Color Code (BCC) (0 – 7). e.g. 62. It is decoded by mobile on every Sync. Channel Message.

•Mode: It is shows in which state is mobile operating, Idle, Dedicated & Packet.

•Time slot: On which time slot of current TCH call is going on. Viz. time slot no. of TRX.

•Channel Type: Type of channel mobile is getting now. Like BCCH / SDCCH/8 + SACCH/C8 or CBCH / TCH/F +FACCH/F +SACCH/F.

•Channel Mode : Shows mode of coding like Speech Full Rate of Half Rate.

•Speech Codec: It shows FR for Full Rate, HR for Half Rate & EFR for Enhanced Full Rate.

•Ciphering Algorithm : It shows ciphering algorithm used by the system to protect data for privacy. E.g. Cipher by A5/2.

•Sub Channel Number: It is displayed at a time when mobile is on dedicated mode at time of call setup when it is getting SDCCH at that time it shows which SDCCH it is getting out of 8 available. E.g. 2.

•Hopping Channel : It shows that current sector is having hopping feature or not. Values are Yes or No.

•Hopping Frequencies : It displays no. of freq. on which mobile is allowed to hop. viz. MA List for hopping of that sector.

•Mobile Allocation Index Offset (MAIO): It is the number which tells from which freq. from given MA list for sector hopping has to be started. E.g. 0 means sector will start from first freq. to hop.

•Hopping Sequence Number (HSN) : Indicates sequence in which frequencies are allowed to hop from the MA List. 0- 63. 0 for Cyclic Hopping, 1 – 63 random hopping sequences.

Steps for Drive Test -2

Following is the procedure and parameters that need to checked while performing Drive Test for a New Site.

• CPC (Cell Parameter Check)

• MOC (Mobile Originated Calls)

• MTC (Mobile Terminated Calls – Prepaid to Postpaid)

• SMS (Short Messaging Service)

• GPRS

• Intra Site Handover

• Inter Site Handover

• TRX Test

• Idle Drive (Normal Drive & Frequency Lock Drive)

• Dedicated Drive

Steps for Drive Test -1

Physical Verification

Physical Verification is carried out by verifying physical parameter of the New Site with the TSSR (Technical Site Survey Report) such as Address, Lat, Long, Building Height, Antenna Height, Antenna Type, Orientation, Tilt.

Alarm Verification

Alarms are generated mainly due to number of reasons, and these needs to checked before Drive is being carried out for the Site. Alarms are checked from the NOC (Network Operating Centre) and if found needs to be verified before drive being carried out.

Frequency Plan Verification

Frequency Plan can be verified from the NOC (Network Operating Centre) for BCCH and TCH frequencies being implemented as per the Site Integration Sheet sent to NOC (Network Operating Centre).

Hardware Configuration Verification

Hardware verification is performed to know the Site type, BTS Type, TRX Configuration, VSWR checking , Power measurement for each TRX.

Golden Rules for collecting Data during drive test

1- Choose the site under surveying to be above the clutter and repeat types of the clutter you would be looking at.

2- Any thing with clutter less than 100 is not enough.

3- Make sure that the GPS surveying option is the same as the one used where the drive test is being performed.

4- Make sure that the Dautch value of the GPS is the same as the one set for the country where the drive test is being made.

5- Better collect data in the format of, Degrees: Decimal Points Degrees.

6- Every 6 degrees you move result is one point change in the whole picture the UK being the reference point at 30, To the left it increases and to the right it decreases.

7- Sampling rate, 40 Samples per 40 wavelengths. To reduce the effect of Radio fading.

8- Sampling can be in Distance and Time. Better do it in Distance especially if you are driving in traffic jams.

9- Do not drive away too much from the site.

10- Drive in to the Site passing through the clutter as well as crossing the clutter

11- Try and drive many roads close to the site unless the clutter is so important.

12- Try to avoid driving the same road twice.

13- Do not drive over a bridge or in to a tunnel inside a clutter area, otherwise take that parts of data a out of the data file collected for this clutter.

14- Make short calls and Long calls, Short calls is the average duration by customers, short calls are to know whether calls will survive the setup and the termination successfully, it also determines the setup time…

15- Long calls are to test the hand over capabilities.

16- Adjacent channels are channels with coverage of 9db more than the serving cell.

17- The co-channel interference is interference from channels have frequency lower the serving channel.

18- For the adjacent channel you could be served from this adjacent channel but the system can not read it and it gives the name of another channel

19- The 6 neighboring cells are those who are listed in the scan list these do not mean that these are the only channels that the phone can see.

20- You have to make sure of the values you are getting out of the surveying equipment do actually make sense.

21- Know the exact power out of the antenna, ERP level, (Effective Radiation Power).

22- Everything about the antenna conditions, during the test time should be reported in the final report.

23- Weather conditions should be reported as well.

24- Know the distance and direction of any buildings blocking your way.

25- Finally, report all sorts of problems.

OM Subsystem and Power Supply Principle

OM Subsystem

The OM subsystem enables the management and maintenance of the BSC6900 in the following scenarios: routine maintenance, emergency maintenance, upgrade, and capacity expansion.

Functions

The OM subsystem provides:

l 4.4.4 Data Configuration Management

l 4.4.5 Security Management

l 4.4.6 Performance Management

l 4.4.7 Alarm Management

l 4.4.8 Loading Management

l 4.4.9 Upgrade Management

l 4.4.10 BTS Loading Management

l 4.4.11 BTS Upgrade Management

Hardware Involved

The OM subsystem consists of the OMUa board, OMUb board, or GBAM.

OMUa = Operation and Maintenance Unit REV:a

Power Supply Principle

The power supply subsystem of the BSC6900 adopts the dual-circuit design and point-by-point monitoring solution. It consists of the power input part and the power distribution part.

The power supply subsystem of the BSC6900 consists of the -48 V DC power system, DC power distribution frame (PDF), and DC power distribution box (PDB) at the top of the cabinet.

If a site has heavy traffic or more than two switching systems, two or more independent power supply systems should be provided. In the case of a communication center, independent power supply systems should be configured on different floors to supply power to different equipment rooms.

Hardware Involved BSC6900

Hardware Involved

The clock synchronization subsystem consists of the GCUa/GCGa board.

The clock board of the BSC6900 can be the GCUa or GCGa board. The BSC6900 cannot

be configured with both the GCUa and GCGa boards simultaneously. Depending on the

clock type, it can have either the GCUa board or the GCGa board.

The active and standby clock boards in the MPS are connected to the active and standby SCUa boards in the EPS through the Y-shaped clock signal cables. This connection mode ensures that the system clock of the BSC6900 works properly in the case of a single-point failure of the clock board, Y-shaped clock signal cable, or SCUa board. In addition, the Y-shaped clock signal cable ensures the proper working of the SCUa boards during the switchover of the active and standby clock boards.

Clock Synchronization Subsystem BSC6900

The clock synchronization subsystem provides clock signals for the BSC6900, generates the RNC Frame Number (RFN), and provides reference clock signals for base stations.

(RFN Generation and Reception

RNC Frame Number (RFN) is used to synchronize NodeBs with the BSC6900. The node synchronization frames from the BSC6900 to the NodeBs carry the RFN information. Figure 1 shows the process of RFN generation and reception. This figure takes the GCUa board as an example.)

Functions

The clock synchronization subsystem provides the following clock sources for the BSC6900 and ensures the reliability of the clock signals:

• Building Integrated Timing Supply System (BITS) clock
• Global Positioning System (GPS) clock
• External 8 kHz clock
• LINE clock

External Clocks

The external clocks of the BSC6900 are of two types:

· BITS Clock

§ The BITS clock signals are of three types: 2 MHz, 2 Mbit/s, and 1.5 Mbit/s. The 2 MHz and 2 Mbit/s clock signals are E1 clock signals, and the 1.5 Mbit/s clock signals are T1 clock signals.

§ The BITS clock has two input modes: BITS0 and BITS1. BITS0 and BITS1 correspond to the CLKIN0 and CLKIN1 ports on the GCUa/GCGa board respectively. The BSC6900 obtains the BITS clock signals through the CLKIN0 or CLKIN1 port.

· External 8 kHz Clock

Through the COM1 port on the GCUa/GCGa board, the BSC6900 obtains 8 kHz standard clock signals from an external device.

LINE Clock

The LINE clock is an 8 kHz clock that is transmitted from an interface board in the MPS to the GCUa/GCGa board through the backplane channel. The LINE clock has two input modes: LINE0 and LINE1.

LINE0 and LINE1 correspond to backplane channel 1 and backplane channel 2 respectively.

The BSC6900 provides reference clock sources for base stations. Clock signals are transmitted from the BSC6900 to base stations over the Abis/Iub interface.

Interface Processing Subsystem BSC6900

Interface Processing Subsystem

Position of the Interface Processing Subsystem in the BSC6900 System

The interface processing subsystem consists of three types of interfaces: ATM interfaces, IP interfaces, and TDM interfaces. Figure 3-13 and Figure 3-14 show the position of the interface processing subsystem in the MPS/EPS and TCS respectively, with the interfaces highlighted in apricot.

Functions

· The interface processing subsystem provides the following types of ATM, IP, and TDM interfaces.

– E1/T1 electrical ports

– Channelized STM-1/OC-3 optical ports

– Unchannelized STM-1/OC-3 optical ports

– FE/GE electrical ports (FE= Fast Ethernet, GE=Gigabit Ethernet)

– GE optical ports

· The interface processing subsystem processes transport network messages and, also hides differences between them within the BSC6900.

· On the uplink, the interface processing subsystem terminates transport network messages at the interface boards. It also transmits the user plane, control plane, and management plane datagrams to the corresponding service processing boards. The processing of the signal flow on the downlink is the reverse of the processing of the signal flow on the uplink.

Hardware Involved

The interface processing subsystem consists of the Iu, Iur, Iub, Abis, A, Ater, Gb, and Pb

interface boards

Service Processing Subsystem BSC 6900

Service Processing Subsystem

The BSC6900 service processing subsystem performs the control functions defined in the 3GPP protocols and processes services of the BSC6900.

The service processing subsystem mainly consists of four logical modules: RNC control lane (CP), RNC user plane (UP), BSC CP, and BSC UP.

Functions

The service processing subsystem performs the following functions:

l User data transfer

l System admission control

l Radio channel ciphering and deciphering

l Data integrity protection

l Mobility management

l Radio resource management and control

l Cell broadcast service control

l System information and user message tracing

l Data volume reporting

l Radio access management

l CS service processing

l PS service processing

Hardware Involved

The service processing subsystem consists of the SPUa, SPUb, XPUa, XPUb, DPUb, DPUc, DPUd, and DPUe boards. The SPUa, SPUb, XPUa, and XPUb boards process signaling. The DPUb, DPUc, DPUd, and DPUe boards process services.

DPUb = Data Processing Unit REV:b (UMTS)

DPUc = Data Processing Unit REV:c (GSM)

DPUd = Data Processing Unit REV:d (GSM)

DPUe = Data Processing Unit REV:e (UMTS)

SPUb = Signaling Processing Unit REV:b

XPUb = eXtensible Processing Unit REV:b

The switching subsystem BSC6900

The switching subsystem

The switching subsystem consists of logical modules of two types: MAC switching and TDM switching. Figure 3-5 and Figure 3-6 show the position of the switching subsystem in the MPS/ EPS and TCS respectively, with the modules highlighted in apricot.

Functions

· Provides intra-subrack Medium Access Control (MAC) switching

· Provides intra-subrack Time Division Multiplexing (TDM) switching

· Provides inter-subrack MAC switching and TDM switching

· Distributes clock signals and RFN signals to the service processing boards

Hardwar Involve

The switching subsystem consists of the SCUa boards, TNUa boards, high-speed backplane channels in each subrack, crossover cables between SCUa boards, and inter-TNUa cables.

SCUa : GE Switching network and Control Unit REV:a

TNUa : TDM switching Network Unit REV:a

SCUa

l Provides MAC/GE switching and enables the convergence of ATM and IP networks.

l Provides data switching channels.

l Provides system-level or subrack-level configuration and maintenance.

l Distributes clock signals for the BSC6900

l BSC6900 GSM and BSC6900 UMTS

TNUa

l Provides the TDM switching and serves as the center of the circuit switched domain.

l Assigns the resources of the TDM network and establishes the network connection.

l Provides communication processing on the GE port.

Network Topologies Between Subracks

In the switching subsystem of the BSC6900, the star topology is established among the MAC switching logical modules, and the mesh topology is established among the TDM switching logical modules.

Inter-Subrack Connection

The MAC switching logical modules switch the ATM/IP traffic data, OM signals, and signaling.

The switching is performed by the SCUa boards and the Ethernet cables between the SCUa boards. The inter-subrack connections related to MAC switching can be classified into the following types:

Interconnections between the MPS and the EPSs

The MPS functions as the main subrack, and a maximum of five EPSs function as extension subracks. The star interconnections between the MPS and the EPSs are established through the Ethernet cables between the SCUa boards, as shown in Figure 3-8.

Interconnections between the TCSs

One TCS functions as the main subrack, and a maximum of three TCSs function as extension subracks. The star interconnections between the TCSs are established through the Ethernet cables between the SCUa boards, as shown in Figure 3-9.