User's Manual

Ver.
CHAPTER 1. Samsung LTE System Overview
2600-00FKQFGA2
1.0
The PDCP layer performs the following functions.
 Header compression and decompression
 Encrypts/decrypts user plane and control plane data
 Protects and verifies the integrity of control plane data
 Transmits data including sequence number related function
 Removes data and redundant data based on a timer
The RRC layer performs mobility management within the wireless access network,
maintaining and control of the Radio Bearer (RB), RRC connection management, and
system information transmission, etc.
MME
The MME interworks with the E-UTRAN (eNB) to process the Stream Control
Transmission Protocol (SCTP)-based S1 Application Protocol (S1-AP) signaling messages
for controlling call connections between the MME and the eNB and to process the SCTP-
based NAS signaling messages for controlling mobility connection and call connection
between the UE and the EPC.
The MME is responsible for collecting/modifying the user information and authenticating the
user by interworking with the HSS. It is also responsible for requesting the allocation/
release/change of the bearer path for data routing and retransmission with the GTP-C
protocol by interworking with S-GW.
The MME interworks with the 2G and 3G systems, the SGSN and the MSC for providing
mobility and Handover (HO), Circuit Service (CS) Fallback and Short Message Service
(SMS).
The MME is responsible for inter-eNB mobility, idle mode UE reachability, Tracking Area
(TA) list management, choosing P-GW/S-GW, authentication, and bearer management.
The MME supports mobility during inter-eNB handover and the inter-MME handover.
It also supports the SGSN selection function upon handover to a 2G or 3G 3GPP network.
S-GW
The S-GW acts as the mobility anchor during inter-eNB handover and inter-3GPP handover,
and routes and forwards user data packets. The S-GW allows the operator to apply
application-specific charging policies to UE, PDN or QCI and manages the packet
transmission layers for uplink/downlink data.
The S-GW also supports GPRS Tunneling Protocol (GTP) and Proxy Mobile IP (PMIP) by
interworking with the MME, P-GW, and SGSN.
PDN Gateway (P-GW)
The P-GW is responsible for charging and bearer policy according to the policy and
manages charging and transmission rate according to the service level by interworking with
the PCRF. The P-GW also performs packet filtering for each user, IP address allocation for
each UE, and downlink data packet transmission layer management.
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