4RF Aprisa LTE, User Manual

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24 | Introduction
Aprisa LTE User Manual 2.1
The following describes the LTE/E-UTRAN components / entities.
Component Description
UE A UE (User Equipment) mobile device connects to an eNB. It is uniquely identified by
their IMEI/IMSI (International Mobile Equipment/subscriber Identity). UE contain a
SIM (Subscriber Identity Module) or USIM (Universal SIM) that holds the subscriber
credentials associated with accessing services (IMSI, keys, ect).
eNB An eNB serve as the base station within the E-UTRAN and provides users with the
radio interfaces and performs Radio Resource Management (RRM) functions such as
dynamic resource allocation, radio admission control, connection mobility control
and Radio Bearer (RB) control and Inter-Cell Interference Coordination (ICIC),
security and conducting inter eNB handover via X2 interface.
The following describes the EPC components / entities.
Component Description
MME An MME is the main control entity for the E-UTRAN. It communicates with an HSS for
user authentication and user profile download and provides UEs with EPS Mobility
Management (EMM) and EPS Session Management (ESM) functions using NAS signaling
and it support the following main functions:
NAS (Non-Access Stratum) signaling manage the establishment and continues
communication sessions with the UE as it moves (EMM, ESM and NAS Security)
User authentication and roaming with HSS
Mobility management (Tracking Area (TAI) and handover management)
EPS bearer management
S-GW An S-GW terminates the interface towards an E-UTRAN. It serves as the local
mobility anchor point of data connections for inter-eNB and inter-3GPP handover.
P-GW A P-GW provides a UE with access to a PDN by assigning an IP address from the
address space of the PDN. The P-GW serves as the mobility anchor point for
handover between 3GPP and non-3GPP. It also performs policy enforcement, packet
filtering and charging based on the PCC rules provided by a PCRF and it support the
following main functions:
IP routing and forwarding
Per-SDF (Service Data Flow i.e. QoS)/Per-User based packet filtering
UE IP address allocation
Mobility anchoring between 3GPP and non-3GPP
PCEF (Policy and Charging Enforcement Function) functions
Charging per-SDF/per-User
HSS An HSS is the central DB where user profiles are stored. It provides user
authentication information and user profiles to the MME.
PCRF
A PCRF is the policy and charging control entity. It makes policy decisions for SDFs
and provides the PCC rules (QoS and charging rules) to the PCEF (P-GW).
SPR A SPR provides subscription information (access profile per subscriber) to the PCRF.
Receiving the information, the PCRF performs subscriber-based policy and creates
PCC rules.
DRA A DRA (Diameter Routing Agent) enables the appropriate PCRF discovery and
selections associate with subscriber.
OCS An OCS provides a real-time credit control and a charging functions based on
volume, time and event.
OFCS An OFCS provides CDR (Charging Data Record) based charging information.