Part – A Two marks

1. What is mobility management?

The mobility is a core feature of 5GS. Mobility Management is required to ensure the
following:
• That the network can “reach” the user, for example to notify the user about incoming
messages and calls,
• That a user can initiate communication toward other users or services such as Internet
access, and that connectivity and ongoing sessions can be maintained as the user moves,
within or between access technologies.
2. What are the mobility management functions?
• Service Area Restriction
• Local Area Data Network (LADN)
• Mobile Initiated Connection Only (MICO)
3. What is Service Area Restriction?
Mobility with session continuity is controlled at UE level at certain areas
4. Local Area Data Network (LADN)?
Mobility with session continuity is controlled at PDU Session level making
communication available at certain areas
5. Mobile Initiated Connection Only (MICO)?
Paging capability (as part of the mobility service) is optional.
6. What are the 5G Mobility Management (5GMM) related procedures?
✓ Common procedures
✓ Specific procedures
✓ Connection management procedures
7. What is Registration and Mobility?
Radio networks are built by cells that range in size from tens and hundreds of meters to
tens of kilometers and the UE updates the network about its location on a regular basis.
8. What is paging?
Paging is sending message and it is used to search for Idle UEs and establish a signalling
connection. Paging is, for example, triggered by downlink packets arriving to the UPF.

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9. What is Mobile Initiated Connection Only (MICO) mode?
Mobile Initiated Connection Only (MICO) mode was introduced to allow paging resources
to be saved for UEs that don’t need to be available for Mobile Terminating communication.
When the UE is in MICO mode, the AMF considers the UE as unreachable when the UE
is in CM-IDLE state.
10. What is RRC Inactive?
It includes support for efficient communication with minimal signalling by using a concept
called RRC Inactive which affects the UE, NG-RAN and 5GC. RRC Inactive is a state
where a UE remains in CM-CONNECTED state (i.e. at NAS level) and can move within
an area configured by NG-RAN (the RAN Notification Area – RNA) without notifying the
network.
11. How are the 5GC assistance information divided?
✓ Core Network assisted RAN parameters tuning.
✓ Core Network assisted RAN paging information.
✓ RRC Inactive Assistance Information.
12. What is Service Area and Mobility Restrictions?
Mobility Restrictions enables the network, mainly via subscriptions, to control the Mobility
Management of the UE as well as how the UE accesses the network. Similar logic as used
in EPS is applied in 5GS, but with some new functionality added as well.
13. What is RAT restriction?
Defines the 3GPP Radio Access Technologies a UE is not allowed to access in a PLMN
and may be provided by the 5GC to the NG-RAN as part of the Mobility Restrictions. The
RAT restriction is enforced by the NG-RAN at connected mode mobility.
14. What is Forbidden Area?
A Forbidden Area is an area in which the UE is not permitted to initiate any communication
with the network for the PLMN.
15. What is Core Network type restriction?
Defines whether UE is allowed to access to 5GC, EPC or both for the PLMN.
16. What is Service Area Restriction?
Defines areas controlling whether the UE is allowed to initiate communication for services.

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17. What is Allowed Area?
In an Allowed Area, the UE is permitted to initiate communication with the network as
allowed by the subscription.
18. What is Non-Allowed Area?
In a Non-Allowed Area a UE is “service area restricted” meaning that neither the UE nor
the network is allowed to initiate signalling to obtain user services (both in CM-IDLE and
in CM-CONNECTED states).
19. What is control overhead?
5GS supports the ability to control the amount of load UEs produce toward the 5GS through
different mechanisms. Mechanisms for 5GC to balance load across NFs and also to scale
the amount of resources consumed for the NFs are often enough to handle normal
fluctuations of load impacting the 5GC.
20. What are the mechanisms used to control overload in 5G?
✓ Congestion in control channel resources
✓ Congestion in random access channel (RACH) resources
✓ Release/reject UE RRC connection
21. What is Congestion in control channel resources?
5QI-based scheduling controls cases when e.g. the number of users awaiting scheduling
exceeds the number of users that can be admitted such that the random access procedure
fails.
22. What is Congestion in random access channel (RACH) resources?
Random access back-off. This pushes some UEs into a longer back-off. This is when there
are so many access attempts on the RACH that the UE provided preambles cannot be
detected anymore.
23. What is Release/reject UE RRC connection?
If there are not enough resources to process RRC connection requests, Releasing RRC
connection or rejecting RRC connection attempts can be used.

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 24. What is Unified Access Control?
EPS supports multiple variants of access barring mechanisms as they were developed in
different releases to address different needs for congestion control. The 5GS supports one
mechanism called Unified Access Control (UAC) which is extensible, flexible (e.g. each
operator can define their own category when to apply access control) and supports a variety
of scenarios.
25. What are the Interworking with EPC using 3GPP access options?
✓ In single-registration mode
✓ In dual-registration mode
26. What is Command and Control Method?
The conventional method for allocating spectrum is known as “Command and Control
Method. There are some countries following this technique of spectrum allocation. In this
method radio spectrum is divided into different spectrum bands that are allowed to specific
radio communication services such as satellite services, mobile, broadcast on an exclusive
basis.
27. What is Spectrum Sharing?
It is sharing of available spectrum. The demand for multimedia content and information
processing, services such as e-education and e-health, mobile broadcasting, enormous
increase in the electronic gadgets necessitate efficient use of all available and usable
frequency spectrum.
28. What is Spectrum Trading?
Spectrum trading is a case of spectrum sharing with the involvement of commercial
activities. Spectrum trading is found to be a more economical way of efficient use of
spectrum. It is an option through which flexibility can be increased and spectrum assigned
to a particular service, and can be easily transferred for other usage.
29. List the merits of spectrum trading?
• Improves efficient spectrum usage
• Facilitates the evaluation of spectrum licenses, and gaining knowledge of market value
of spectrum
• Quicker process, with better and faster decision-making by those with information
• Removes barriers to entry by allowing small operators and start-ups to acquire spectrum
rights of use more readily, thereby facilitating the development of market competition
• There is an opportunity for more rapid redeployment and faster access for spectrum
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30. Define Cognitive Radio.( Nov/Dec 23)
IEEE approved definition of cognitive radio (CR) is a radio in which communication
systems are aware of their environment and internal state, and can make decisions about
their radio operation based on that information and predefined objectives.
31. What are the self-organizing features of Cognitive radios?
✓ Spectrum resource management
✓ Security management
✓ Mobility and connection management
32. What is Spectrum Handover?
The phenomenon of frequency changing dynamically is said to be spectrum handover. A
secondary user changes its frequency on appearance of a primary user or due to
transmission degradation. This necessitates designing a handover scheme.
33. Define Millimeter (MM) Wave (Nov/Dec 23)
Millimeter wave (MM wave), also known as millimeter band, is the band of spectrum with
wavelengths between 10 millimeters (30 GHz) and 1 millimeter (300 GHz). It is also
known as the extremely high frequency (EHF) band by the International
Telecommunication Union (ITU).
34. List the Advantages of millimeter (MM) wave
Millimeter wave is a band of electromagnetic spectrum that can be used in a broad range
of products and services, such as high-speed, point-to-point wireless local area networks
(WLANs) and broadband access. In telecommunications, millimeter wave is used for a
variety of services on mobile and wireless networks, as it enables higher data rates than at
lower frequencies, such as those used for Wi-Fi and current cellular networks.

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