Telecom General Interview Preparation Guide

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ANDREW (65*, 90*)
KATHREIN,
TIL-TEK,
ALGON.

(THEY ALL ARE THE DIRECTIONAL ANTENNA'S USED BY THE TELECOMMUNICATION SERVICE PROVIDER OPERATOR'S. LIKE AIRTEL, VODAFONE, IDEA, B.S.N.L, TATA-DOCOMO, RELIANCE ETC)

7/8'"din male if feeder is 7/8,or 7/16'" if feeder is 1/2

1> TNC Male Connector is used in FIFA card.

2> SMB Connector is used in FIEA card.

3> RJ48c Connector is used in FIPA card.

in flexi in hardware one trx is two trx , means in one sector

2 trx (hardware device) in first sector.

2 trx (hardware device) in 2nd sector.

2 trx (hardware device) in 3rd sector.


total 6 trx (hardwar device)

This diagram shows that the GSM system uses a single type of
radio channel. Each radio channel in the GSM system has a
frequency bandwidth of 200 kHz and a data transmission rate
of approximately 270 kbps. This example shows that each
radio communication channel is divided into 8 time slots (0
through 7). This diagram shows that a simultaneous two-way
voice communication session requires at least one radio
channel communicates from the base station to the mobile
station (called the forward channel) and one channel
communicates from the mobile station to the base station
(called the reverse channel). This example also shows that
some of the radio channel capacity is used to transfer voice
(traffic) information and some of the radio channel capacity
is used to transfer control messages.


Normal Burst Structures

This figure shows the field structures of the normal burst
used in the GSM system. This diagram shows that the field
structure is different for the normal burst, synchronization
burst, and the frequency correction bursts. The fields
transmitted during the normal burst include initial tail
bits (ramp-up time), training sequence, flag bits, user data
bits, final tail bits, and guard period. This diagram shows
that the first 3 bits of the time slot are dedicated to the
gradual increase of transmitter power level (ramp-up). For
the normal burst, this is followed by the information (user
data) bits. The flag bits indicate if the normal burst has
been replaced with FACCH signaling information. This diagram
shows that some of the bits in the center of the burst are
used as training bits (to allow equalizer training). At the
end of the transmitted burst there are tail bits (for error
protection) and 3 guard period bits that are used during the
gradual reduction of the RF transmitter signal (ramp-down).



Fast Associated Control Channel (FACCH) Signaling

This figure shows that GSM FACCH signaling replaces (steals)
speech frames and replaces them with control information.
This example shows the FACCH messages is divided and
transmitted over 8 sequential channel bursts and that the
speech information that would normally be transmitted is
discarded. When received, the FACCH message is reassembled
into its original message structure.

TRAU Means the Transmission Rate Adaptation
Unit.Actually,it is a Transcoder unit(XCDR).it uses as an
interface B/W BSC & MSC.it converts 16kbps data into 64
Kbps and vice versa.

Absolute Radio Frequency Channel Number.

There will always 20db descriminationation between
vertically and horizontally polarised antennas

FC RRI Card
2. FC E1/T1 Card
3. FXC RRI Card
4. FXC E1/T1 Card
5. FXC E1 Card
6. Dummy Car
XC RRI,FXCE1/T1 two types of cards

1 RRI card,1 E1T1 card ,FIU card and TRX card depend upon
the configuration

NOKIA BTS DIVIDE IN FOLLOWING UNITS:

1. POWER CARDS
2. BB2F
3. Trx
4. BOIA CARD
5. ALARM EXTENSION SYSTEM
6. RRI CARD
7. COMBINER
8. DUPLEXER

pwsb is known as power supply card and it is used for the power distribution to trx cards in case of ultra bts and dtrx cards in case of flexi bts

there are 6 slots in ESMA , we can use all of the 6 while connecting 6 dtrx in 4,4,4 mode but if we want to add sectors then we will require ESEA for this we need to vaccant one slot to connect ESMA to ESEA, but ESEA has 12 slots so total 12+5 slots can be used

3(HEIGHT UNIT)

generally height of an antenna is 45m to 70m accorading to
as par geographycal area hight........it is change from
area to area.........

BTS abbreviated for Base Transiever Station is a collection of transmission and reception card designed for routing of signals from end user to msc and vice versa.
There are many types of BTS depending on the manufacturing companies viz nokia,ericcsion, zte,huwai etc ...i've worked on a few so can tell u about them
in nokia there is practically 2,2,2/4,4,4/8,8,8 configuration but this may vary depending upon the traffic requirement of the circle. mostly composite configurations are used, like 2,3,3 or 2,2,4 etc.
these nos are nothing but no of trx cards in each sector , for example 2,2,2 is 2 trx cards in each of three sectors.
power consumption also is different for each type of BTS, for NOKIA's Flexi indoor BTS running on 222 config power requiremnt will be approx 48 watts per hour
typically on every BTS 48V is supplied with negative polarity.
feel free to mail me for any further doubts

Blackberry is a top most Brant & high speed internet using
cell phone on this cell phone available many more advanced
options so very comparable cell phone for every parson

Because it is very low value which have less loss of signal and less interfernce.

2100 MHZ Not 2100 only

43dbm/20Watt is the output power of one TRx.The total output power depends on the number of Trx.

as per the utilization of sector,we can configure the
sectors a,b,c like below combination...
if 1st sector utilization is high 4+2+2
if 2nd sector utilization is high 2+4+2
if 3rd sector utilization is high 2+2+4

Network operation center (NOC). NOCs are responsible for
monitoring the network for alarms like as power fail,
Service affected alarm (site down,LAPD OML fault, TRX close
HPA alarm etc)& communicate its field engineer to solved the
problem. if need any support for software base they provide
to recover the problem.

A Network Management System (NMS) is a combination of
hardware and software used to monitor and administer a
network. Communicate with NOC recover the Alarm.

NMS-->NOC-->Field Engineers=Solved the problem

make a server and check individual internet speed

VSWR STANDS FOR VOLTAGE STANDING WAVE RATIO

THE RATIO OF THE MAXIMUM TO MINIMUM VALUE OF STANDING WAVE
PATTERN ALONG A TRANSMISSION LINE TO WHICH A LOAD IS CONNECTED.

IT SHOW HOW MUCH SIGNAL IS TRANSMITTED AND REFLECTED BACK.

USING SITE MASTER WE CAN MEASURE VSWR.
ITS RANG IS 1.00-1.30

Bluetooth Works on 2.4 GHz

The time taken for 1 satellite hop in voice
communication is 1/2 seconds