The GSM architecture consists of two things, namely them.
Base Station System, and Network Switching Subystem
The Base Station System (BSS) consist of what components?
Base Tranceiver Station (BTS), and Base Station Controller (BSC)
The Network Switching Subsystem consist of which components?
ACV - HOMAGES
The Mobile Station (MS) consist of the _______ and __________.
Mobile Equipment (ME) and SIM
What component holds the Phoen Book, PRL, BRL, MSISDN, security vectors, etc..
International Mobile Subscriber Identifier (IMSI)
Besides looking at the back of the battery to locate the IMEI, you can also do what?
Dial *#06#
The Mobile Equipment (ME) is assigned a ___-digit number called the International Mobile Equipment Identifier (IMEI)
What does IMEI stand for?
International Mobile Equipment Identifier (IMEI)
The first 8-digits of the IMEI are called what?
Type Allocation Code (TAC)
The TAC provides what information?
Make and Model of the device
What are the 6-digits proceeding the TAC?
Serial Number (SN)
The final digit of the IMEI is called what?
Check Digit (CD) - some newer devices have the Software Version (SV)
How many digits does the IMSI contain?
15-digits
What does IMSI stand for?
International Mobile Subsccriber Identifier (IMSI)
The first 3-digits of the IMSI is called what?
Mobile Country Code (MCC)
The 3-digits proceeding the MCC is called what?
Mobile Network Code (MNC)
The United States is assigned which MCCs?
310-316 *Usually only use 310 and 311 currently*
The last 9-10 digits proceeding the PLMN are called what?
Mobile Subscriber Identity Number (MSIN)
What is used for security purposes to mask the IMSI and minimize the number of times it is sent over the air?
Temporary Mobile Subscriber Identity (TMSI)
A TMSI consist of a ____-hexadecimal number assigned by a VLR.
The ____________ is a subscribers phone number.
Mobile Subscriber Integrated Service Digital Network (MSISDN)
The _____ is unique to the SIM. It is associated with and ID's a specific user. It is never passed over the air and only stored on the user's SIM and at the AuC.
Ki
_______ is specific to a user and created fore very new session; referred to as a "session key." It is also part of the "Triplets"
Kc
An ______________ is a type of BTS that covers several microcells to reduce the number of handoffs on the network. It fills coverage gaps.
Umbrella Cell
True/False: All Authentication Center (AuC) queries are routed through the Home Location Register (HLR).
The first 6-digits of the IMSI make up what?
Public Land Mobile Network (PLMN)
The Location Area Identification (LAI) is comprised of what three things?
MCC, MNC, and LAC
The ________ differentiates each LAC from all other LACs in the world.
Location Area Identification (LAI)
The ________ denotes a specific panel on a BTS.
Cell Identity (CID)
What four things make up the Cell Global Identification (CGI)?
PLMN, LAC, and CID
The BSIC is comprised of what two things?
Base Station Color Code (BCC), and Network Color Code (NCC)
The ________ is used to differentiate between networks utilizing the same frequencies.
NCC
The ________ is used to differentiate between panels using the same frequencies.
BCC
The BSIC is sent on the ________________ Channel.
Synchronization Channel (SCH)
Numerical values for the BCC and NCC are ____ to ____.
0-7
The ________________ is a geographical grouping of the BTS and BSCs controlled by a MSC/VLR.
Location Area (LA)
What are the two Access Schemes utilized in GSM?
TDMA and FDMA
In ________ each user occupies a private frequency protected from user interference through physical separation.
Frequency Division Multiple Access (FDMA)
In ________ each user occupies a specific frequency but only during an assigned time slot.
Time Division Multiple Access (TDMA)
GSM is _______ duplex.
Half
An ARFCN is comprised of __________ frequencies.
2 *Uplink or Forward, and Downlink or Reverse*
ARFCNs use _________ modulation
Gaussian Minimum Shift Keying (GMSK)
Name the four bands utilized in GSM:
Band 900 (GSM), Band 1800 (DCS), Band 1900 (PCS), and BAnd 850 (Cellular)
What channels (ARFCNs) does the 900 (GSM) band utilize?
0 - 124
What channels (ARFCNs) does the 1800 (DCS) band utilize?
512 - 885
What channels (ARFCNs) does the 1900 (PCS) band utilize?
512 - 810
What channels (ARFCNs) does the 850 (Cellular) band utilize?
128 - 251
The higher frequency in an ARFCN pair tends to be the _____________ due to pathloss.
Downlink
An ARFCN pair are spaced _______ apart.
200 KHz
Which GSM bands are typically used in CONUS?
850, and 1900
Which GSM bands are typically used OCONUS?
900, and 1800
What is the offset of the 1800 (DCS) band?
95 MHz
What is the offset of the 900 (GSM) band?
45 MHz
What is the offset of the 1900 (PCS) band?
80 MHz
What is the offset of the 850 (Cellular) band?
45 MHz
A GSM frame is _______ms.
A GSM time slot is. _____usec
Timeslot ____ is typically used by the network to send out Beacon Information.
What are the three Logical Channels?
Beacon, Common Control Channels, and Dedicated Control Channels
How many timeslots are in a GSM frame?
8 *Numbered 0 thru 7*
_____________ are information passed over the Physical Channel.
Logical Channels
This Logical Channel is broadcast 24/7 and is Downlink Only.
Beacon Channel
This Logical Channel begins the process of handset access to the network, and is responsible for initial call setup.
Common Control Channels
This Logical Channel is responsible for call setup and maintenance.
Dedicated Control Channels
Name the various Common Control Channels:
Think "PAR" (Golf Term) - Paging Channel (PCH), Access Grant Channel (AGCH), and Random Access Channel (RACH)
Name the various Beacon Channels:
Think "BSF" (Railroad) - Broadcast Control Channel (BCCH), Synchronization Channel (SCH), and Frequency Correction Channel (FCCH)
Name the various Dedicated Control Channels:
Think "SFS" (USAF Cops) - Standalone Dedicated Control Channel (SDCCH), Fast Associated Control Channel (FACCH), and Slow Associated Control Channel (SACCH)
Which Common Control Channel is uplink only, and used by handsets to request access to the network?
RACH
Which Common Control Channel is downlink only, and grants access to the network?
AGCH
Which channel assigns a Standalone Dedicated Control Channel, as well as timeslot and frame assignment?
AGCH
Which Common Control Channel is downlink only and used to alert handsets they have incoming data?
PCH
Which Dedicated Control Channel is for immediate signaling between networks and handset, and also manages handoffs during TCH.
FACCH
GSM is made up of two types of channels, what are they?
Physical and Logical
In GSM, what are two types of interference we can encounter?
Adjacent Channel, and Co-Channel
What 3 scenarios will cause an MS to conduct a Location Update?
Power Up/Down, Changing LACs, and Periodic Location Updates
Which rejection code means "Roaming Not Allowed?"
Cause Code 13
Which rejection code means "Illegal ME?"
Cause Code 6 aka Deep 6
______ is a value calculated by the MS used to determine a channel's desirability.
C1
The Neighbor List is the top ____ ARFCNs on the BA List.
How often will the MS monitor the serving cell and Neighbor List?
Every 5 seconds
How many ARFCNs are monitored on the BA List?
How many ARFCNs are monitored on the SACCH?
Outside of the serving cell and Neighbor List, the MS will monitor the other BA List ARFCNs every ____ seconds.
How many types of handovers are used in GSM?
What is the C2 formulae?
C2 = C1 + CRO - (Temp Offset * H (Penalty Timer - T))
What makes up the Triplets?
RAND, SRES, Ki
Where is the Ki maintained?
SIM and AuC
RXQual has a value of ___ to ___. It measures call quality.
0 to 7
Which handover is between sectors on the same BTS?
Intra-BTS Handover
Which handover is between different BTSs within the same BSC?
Inter-BTS Handover
Which handover is between BTSs within the same LAC?
MSC Internal
Which handover is between different LACs?
MSC External
What security algorithm is used to generate the SRES?
A3
What security algorithm is used for the Kc?
A8
What security algorithm is used for variable encryption schemes?
A5
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