CUSTOMER_CODE
SMUDE
DIVISION_CODE
SMUDE
EVENT_CODE
JAN2016
ASSESSMENT_CODE MIT4033_JAN2016
QUESTION_TYPE DESCRIPTIVE_QUESTION
QUESTION_ID
23973
QUESTION_TEXT Explain GSM channels in detail
SCHEME OF
EVALUATION
1 .types:
Traffic channels.
Broadcast channels
Common control channels.
Dedicated control channels.
2.Traffic channels
(TCH):
(2.5marks)
Combination of voice and data signals that exit within a communication
channel.
Either half or full rate
Full –rate: raw rate of 22.8Kbps,with a useable rate of 9.6kbps for data.
Half-rate: raw rate of 11.4kbps,useable 4.8kbps for data.
3.Broadcast
channels(BCH):
(2.5marks)
Used in operation of GSM.
3 parts
1)BCCH(The broadcast control channel): logical broadcast channel used
by base station in GSM network to send information about the identity of
the network
2)FCCH(The Freequency correction Channel):used by GSM base stations.
3)SCH(Synchronisation channel):downlink broadcast channel of the base
stations of GSM network. provide information about mobile stations
needed.
4.common control
channels:
(2.5marks)
Used for sending and receiving command messages between devices.
Alert devices about incoming call ,for accessing control.
A)PCH(paging channel): transmits paging message at certain time
interval. B)AGCH(Access Grant Channel): ,c)RACH(Random Access
channel):the base station receives a response from the mobile station
through RACH.
5.Dedicated control
channels:
(2.5marks)
i.Communication channels that transfer signalling messages to specific
devices in a GSM network.
ii.3 dedicated channels are there a)stand alone dedicated control
channel(SDCCH) .b)slow associated control channel(SACCH) .c)fast
associated control channel(FACCH) .
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
23974
QUESTION_TEXT
Explain mobility management in wireless network
1.
(2 marks)
The internet is extending its reach with new mobile applications.
The use of mobile devices is increasing with rapid rate.
Better QOS.
SCHEME OF
EVALUATION
2.Mobility management:
(2 marks)
Support roaming users with mobile terminals to enjoy their services.
Keep track of mobile user and facilitate services like call, sms etc.
It enables a)track out roaming terminals to deliver data packets.
B)maintain connection with terminals moving into new areas
3.temporary mobile subscriber identity(TSMI)
(2
marks)
Sent between mobile and network.
Every mobile in an area is assigned a TSMI
The number should be updated every time when mobile moves to new
location.
4.Roaming: (2 marks)
Enables users to access the network outside the geographical coverage.
Done with cellular coverage of visited network.
User’s subscriber identity is used for this connection establishment.
5.Location area and location update procedure:
(2 marks)
A set of base station are grouped together to optimize signalling
and result in formation of a location area.
Several number of BS shares the same base station controller.
Location update procedure is very important for efficient mobility
management.
Allows mobile device to inform the cellular network about its change in
location from one network area to the other.
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
73084
QUESTION_TEXT
Briefly explain any five identifiers in GSM network.
SCHEME OF
EVALUATION
1. International mobile station equipment identity (IMEI): An identifier is a
kind of serial number assigned to a mobile station called the IMEI. This
identifier uniquely identifies a mobile station internationally. The IMEI is
allocated by the equipment manufacturer and registered by the network
operator and stores the number in the EIR. The EIR or equipment identity
register is a database that contains information about the identity of mobile
equipment that prevents calls from stolen, unauthorized, or defective mobile
stations.
2. International mobile subscriber identity (IMSI): Each registered user is
uniquely identified by its international mobile subscriber identity (IMSI). It is
stored in the subscriber identity module (SIM) which is assigned to the
subscriber by a local GSM operator. A mobile station can only be operated if a
SIM with a valid IMSI is inserted into equipment with a valid IMEI.
3. Mobile subscriber ISDN number (MSISDN): ISDN (Integrated Services
Digital Network) is a set of standards for digital transmission over telephone
network. ISDN requires a special device called adapters at both ends of the
transmission to access the service. In many areas where Digital Subscribers
Link (DSL) and cable modem service are offered as part of the ISDN.
4. Mobile station roaming number (MSRN): The Mobile Station Roaming
Number (MSRN) is a temporary location dependent ISDN number. It is
assigned by the locally responsible VLR to each mobile station in its area. Calls
are also routed to the MS by using the MSRN.
5. Mobile station roaming number (MSRN): The Mobile Station Roaming
Number (MSRN) is a temporary location dependent ISDN number. It is
assigned by the locally responsible VLR to each mobile station in its area. Calls
are also routed to the MS by using the MSRN.
(2 marks each)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
73085
QUESTION_TEXT
Write procedure followed by different components of the network to complete
a call from the PSTN subscriber to a mobile station.
SCHEME OF
EVALUATION
1. The PSTN subscriber dials the mobile telephone number using Mobile
Station ISDN number (MSISDN). A connection request is made to the mobile
stations home GMSC (Gateway Mobile Switching Centre).
2. The home GMSC finds the respective HLR of the called mobile station
and sends a query to the HLR for information about the serving MSC/VLR of
the called mobile station.
(2 marks)
3. The HLR translates MSISDN into IMSI, and determines which MSC/VLR
is currently serving the MS.
4. The HLR requests a Mobile Subscriber Roaming Number (MSRN) from
the serving MSC/VLR of the called mobile station.
(2 marks)
5. The MSC/VLR returns an MSRN via HLR to the GMSC.
6. The GMSC routes the call to the concerned MSC/VLR.
7. The MSC/VLR searches its record to find the current LA of the mobile
station and a paging message is sent to the BSC of the controlling the LA.
(3 marks)
8. The BSC’s uses PCH to page the mobile station.
9. When the mobile station detects the paging message, it sends a request
on RACH for a SDCCH.
10. The BSC provides a SDCCH via AGCH.
(3 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
120035
QUESTION_TEXT
Explain the system operations of GSM.
For explaining mobile telephone initialization – frequency
synchronization, timing synchronization, overhead information
acquisition
(5 marks)
SCHEME OF
EVALUATION
For explaining updating location
For explaining waiting for calls, cell resection, system access, mobile
call origination, transferring calls
(2 marks)
Between call sites, mobile assisted handoff, receiving a call on a
mobile telephone, conversation mode, authentication (3 marks)
QUESTION_TYPE
DESCRIPTIVE_QUESTION
QUESTION_ID
120039
QUESTION_TEXT
List various components of Network Switching Subsystem. Explain
any three of the components.
Various components of NSS are:
SCHEME OF
EVALUATION
i.
Home location register (HLR)
ii.
Mobile switching center and visitor location register (MSC)
iii.
Authentication center (AUC)
iv.
Equipment Identity register (EIR)
v.
Gateway MSC (GMSC)
vi.
GSM interworking unit/function
vii.
Message service gateway (MSG)
viii. Flexible numbering register (FNR)
List these components
4 marks
Explanation about any three components
3X2=6 marks.