Functionality of the network elements is grouped in several domains:
UE Domain
Radio Access Network Domain (LTE)
Core Network Domain (SAE)
Service Domain (IMS)
UE Domain
UE Domain is Consists of UE and Uu Interface.
E-UTRAN Node B - eNB
An eNB is a logical network component which serves one or more E-UTRAN Cells. It is responsible for radio transmission and reception from/to UE. Some of eNodeB functionalities are:
• Cell Control and MME pool support:
• Control and User Plane Security
• Segmentation/Concatenation
• Error Correction
• Shared Channel Handling
• Scheduling
• Physical Layer functions such as channel coding, modulation,
filtering
• Handling of Measurement Control/Reporting
• Mobility Control
An eNB can support FDD mode, TDD mode or dual mode operation.
Core Network Domain (SAE)
Mobility Management Entity MME
MME is the control plane entity within EPS supporting following
functions:
Mobility Management:
• NAS signalling and security
• Inter CN node signalling for mobility between 3GPP access
networks
• Tracking Area list management
• PDN GW and Serving GW selection
• SGSN selection for handovers to 2G or 3G 3GPP access
networks
• Roaming
• Authentication
• Bearer management functions including dedicated bearer
establishment
• Lawful interception of signalling traffic
• Initiating IMSI detach at EPS detach
• Initiating paging procedure towards eNodeB when MSC pages
the UE for CS services
• Supporting SMS procedures for CS fallback.
• Support CS fallback interface and related functions for CDMA
access.
The Home Subscriber Server (HSS)
The HSS is the master database for an operator. It is the entity containing the subscription-related information to support the network entities actually handling calls/sessions. A Home Network may contain one or several HSSs: it depends on the number of mobile subscribers, on the capacity of the equipment and on the organisation of the network. As an example, the HSS provides support to the call control servers in order to complete the routing/roaming procedures by solving authentication, authorisation, naming/addressing resolution, location dependencies, etc.The HSS is responsible for holding the following user related information:
• User identification, numbering and addressing information
• User security information: Network access control information for authentication and authorization
• User Location information at inter-system level: the HSS supports the user registration, and stores inter-system location information, etc.
• User profile information. The HSS also generates User Security information for mutual
authentication, communication integrity check and ciphering. Based on this information, the HSS also is responsible to support the call control and session management entities of the different
domains and subsystems of the operator.
Serving GW
The Serving GW is the gateway which terminates the interface towards E-UTRAN.
For each UE associated with the EPS, at a given point of time, there is a single Serving GW.
Some functions of the Serving GW are listed:
• the local Mobility Anchor point for inter-eNodeB handover
• Mobility anchoring for inter-3GPP mobility
• ECM-IDLE mode downlink packet buffering and initiation of network triggered service request procedure
• Lawful interception
• Packet routing and forwarding
• Transport level packet marking in the uplink and the downlink
• Accounting on user and QCI granularity for inter-operator charging
• A local non-3GPP anchor for the case of roaming when the non-3GPP IP accesses connected to the VPLMN
• Event reporting (change of RAT, etc.) to the PCRF
• Uplink and downlink bearer binding towards 3GPP accesses
• Uplink bearer binding verification with packet dropping of "misbehaving UL traffic"
Packet Data Network Gateway PDN GW
The PDN GW is the gateway which terminates the SGi interface towards the PDN. The P GW provides PDN connectivity to both GERAN/UTRAN only UEs and E UTRAN capable UEs using any of E UTRAN, GERAN or UTRAN. The P GW provides PDN connectivity to EUTRAN capable UEs using E UTRAN only over the S5/S8 interface. Some of PDN GW functions include:
• Per-user based packet filtering (by e.g. deep packet inspection)
• Lawful interception
• UE IP address allocation
• Transport level packet marking in the uplink and downlink, e.g.setting the DiffServ Code Point, based on the QCI of the associated EPS bearer
• UL and DL service level charging, gating control, rate enforcement
• UL and DL rate enforcement based on APN-AMBR
• DL rate enforcement based on the accumulated MBRs of the aggregate of SDFs with the same GBR QCI (e.g. by rate policing/shaping)
• DHCPv4 (server and client) and DHCPv6 (client and server) functions
• Additionally the PDN GW includes the following functions for the GTP-based S5/S8
• UL and DL bearer binding
• UL bearer binding verification
• The PDN GW functions also includes user plane anchor for mobility between 3GPP access and non-3GPP access
SERVICE DOMAIN(IMS)
It is connected with P-GW and PCRF. Actually it is PDN (Internet,AF,Application Servers i.e:Skype,Face Book,Yahoo,Google,Youtube etc)
IP Multimedia Subsystem (IMS) is defined by 3GPP/3GPP2 as acore and service 'domain' that enables the convergence of data,speech and network technology over an IP-based infrastructure.
It is the operator choice of control and service logic for primarily IP/packet-based person-to-person communication but also for person-to-content communication. For users, IMS-based services will enable communications in a variety of modes – including voice, text, pictures and video, or any
combination of these – in a highly personalized and secure way. IMS is designed to fill the gap between the existing traditional telecommunications technology and internet technology that
increased bandwidth alone does not provide. This allows operators to offer new, innovative.
UE Domain
Radio Access Network Domain (LTE)
Core Network Domain (SAE)
Service Domain (IMS)
UE Domain
UE Domain is Consists of UE and Uu Interface.
USER EQUIPMENT (UE)
The User Equipment allows a user access to network services. For the purpose of 3GPP specifications the interface between the UE and the network is the radio interface.A User Equipment can be subdivided into a number of domains,the domains being separated by reference points. Currently the User Equipment is subdivided into the Universal Integrated Circuit Card (UICC) domain and the Mobile Equipment (ME) Domain. The ME Domain can further be subdivided into one or more Mobile Termination (MT) and Terminal Equipment (TE) components showing the connectivity between multiple functional groups.
UU INTERFACE:
The LTE radio interface is based on OFDM (Orthogonal Frequency Division Multiplex) in DL and SC-FDMA (Single Carrier Frequency Division Multiple Access) in UL. These techniques are well suited for flexible bandwidth operation. This enables operators to deploy LTE in different regions with different frequency bands and bandwidths available. In addition to that, both FDD (Frequency Division Duplex) and TDD (Time Division Duplex) is supported, which opens up for deployment in both paired and unpaired spectrum. In FDD, different frequency bands are used for UL and DL. In TDD the UL and DL transmissions are separated in time.
Radio Access Network Domain (LTE)
Radio Access Network Domain (LTE) is Consists of E-UTRAN
RADIO ACCESS DOMAIN
Radio Access Domain is referred as Evolved UTRAN. It consists only of a number of eNodeBs (eNB) that are interconnected via X2 interface through an IP network. The eNBs are connected by means of the S1 interface to the EPC (Evolved Packet Core), more specifically to the MME (Mobility Management Entity) by means of the S1-MME and to the Serving Gateway (S-GW) by means of
the S1-U interface. The S1 interface supports a many-to-many relation between MMEs / Serving Gateways and eNBs.
Evolved Packet System is another naming that group Evolved Packet Core EPC and E-UTRAN. The standard development in 3GPP is grouped into two working groups: Long Term Evolution (LTE) targeting Radio Access Network and System Architecture Evolution (SAE) targeting Core Network.
LTE/SAE naming is commonly used however it is more accurate to use E-UTRA/EPC.
An eNB is a logical network component which serves one or more E-UTRAN Cells. It is responsible for radio transmission and reception from/to UE. Some of eNodeB functionalities are:
• Cell Control and MME pool support:
• Control and User Plane Security
• Segmentation/Concatenation
• Error Correction
• Shared Channel Handling
• Scheduling
• Physical Layer functions such as channel coding, modulation,
filtering
• Handling of Measurement Control/Reporting
• Mobility Control
An eNB can support FDD mode, TDD mode or dual mode operation.
Core Network Domain (SAE)
Core Network Domain (SAE) is Consists of MME,HSS,S-GW and P-GW.
Core Network Domain is referred as Evolved Packet Core (EPC) and consists of following network elements:Mobility Management Entity MME
MME is the control plane entity within EPS supporting following
functions:
Mobility Management:
• NAS signalling and security
• Inter CN node signalling for mobility between 3GPP access
networks
• Tracking Area list management
• PDN GW and Serving GW selection
• SGSN selection for handovers to 2G or 3G 3GPP access
networks
• Roaming
• Authentication
• Bearer management functions including dedicated bearer
establishment
• Lawful interception of signalling traffic
• Initiating IMSI detach at EPS detach
• Initiating paging procedure towards eNodeB when MSC pages
the UE for CS services
• Supporting SMS procedures for CS fallback.
• Support CS fallback interface and related functions for CDMA
access.
The Home Subscriber Server (HSS)
The HSS is the master database for an operator. It is the entity containing the subscription-related information to support the network entities actually handling calls/sessions. A Home Network may contain one or several HSSs: it depends on the number of mobile subscribers, on the capacity of the equipment and on the organisation of the network. As an example, the HSS provides support to the call control servers in order to complete the routing/roaming procedures by solving authentication, authorisation, naming/addressing resolution, location dependencies, etc.The HSS is responsible for holding the following user related information:
• User identification, numbering and addressing information
• User security information: Network access control information for authentication and authorization
• User Location information at inter-system level: the HSS supports the user registration, and stores inter-system location information, etc.
• User profile information. The HSS also generates User Security information for mutual
authentication, communication integrity check and ciphering. Based on this information, the HSS also is responsible to support the call control and session management entities of the different
domains and subsystems of the operator.
Serving GW
The Serving GW is the gateway which terminates the interface towards E-UTRAN.
For each UE associated with the EPS, at a given point of time, there is a single Serving GW.
Some functions of the Serving GW are listed:
• the local Mobility Anchor point for inter-eNodeB handover
• Mobility anchoring for inter-3GPP mobility
• ECM-IDLE mode downlink packet buffering and initiation of network triggered service request procedure
• Lawful interception
• Packet routing and forwarding
• Transport level packet marking in the uplink and the downlink
• Accounting on user and QCI granularity for inter-operator charging
• A local non-3GPP anchor for the case of roaming when the non-3GPP IP accesses connected to the VPLMN
• Event reporting (change of RAT, etc.) to the PCRF
• Uplink and downlink bearer binding towards 3GPP accesses
• Uplink bearer binding verification with packet dropping of "misbehaving UL traffic"
Packet Data Network Gateway PDN GW
The PDN GW is the gateway which terminates the SGi interface towards the PDN. The P GW provides PDN connectivity to both GERAN/UTRAN only UEs and E UTRAN capable UEs using any of E UTRAN, GERAN or UTRAN. The P GW provides PDN connectivity to EUTRAN capable UEs using E UTRAN only over the S5/S8 interface. Some of PDN GW functions include:
• Per-user based packet filtering (by e.g. deep packet inspection)
• Lawful interception
• UE IP address allocation
• Transport level packet marking in the uplink and downlink, e.g.setting the DiffServ Code Point, based on the QCI of the associated EPS bearer
• UL and DL service level charging, gating control, rate enforcement
• UL and DL rate enforcement based on APN-AMBR
• DL rate enforcement based on the accumulated MBRs of the aggregate of SDFs with the same GBR QCI (e.g. by rate policing/shaping)
• DHCPv4 (server and client) and DHCPv6 (client and server) functions
• Additionally the PDN GW includes the following functions for the GTP-based S5/S8
• UL and DL bearer binding
• UL bearer binding verification
• The PDN GW functions also includes user plane anchor for mobility between 3GPP access and non-3GPP access
It is connected with P-GW and PCRF. Actually it is PDN (Internet,AF,Application Servers i.e:Skype,Face Book,Yahoo,Google,Youtube etc)
IP Multimedia Subsystem (IMS) is defined by 3GPP/3GPP2 as acore and service 'domain' that enables the convergence of data,speech and network technology over an IP-based infrastructure.
It is the operator choice of control and service logic for primarily IP/packet-based person-to-person communication but also for person-to-content communication. For users, IMS-based services will enable communications in a variety of modes – including voice, text, pictures and video, or any
combination of these – in a highly personalized and secure way. IMS is designed to fill the gap between the existing traditional telecommunications technology and internet technology that
increased bandwidth alone does not provide. This allows operators to offer new, innovative.
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