Since there exist a system, which basically deal with PHY, MAC and Scheduler functionality of LTE, the new simulation model supports for LTE RLC and PDCP protocol, together with EPC data plane features. This results in end to end IP connectivity over LTE-EPC. For simulation we are using ns-3. In this paper, we provide an overview of the design criteria and architecture of the proposed model.

1. SIMULATION OF END-TO-END IP CONNECTIVITY FOR LTE-EPC
AKSHATHA.H.E1, NAMRATA KATTI2, SANDEEP JAINAPUR3, DEEPTHI RAJ4
1,2,3,4
DSCE.
Abstract- Since there exist a system, which basically deal with PHY, MAC and Scheduler functionality of LTE, the new
simulation model supports for LTE RLC and PDCP protocol, together with EPC data plane features. This results in end to
end IP connectivity over LTE-EPC. For simulation we are using ns-3. In this paper, we provide an overview of the design
criteria and architecture of the proposed model.
Key words- Ns-3,LTE, EPC
eNBs, some of which might be equipped with a backhaul connection with limited capabilities. In order to
simulate such scenarios, the user data plane protocols
being used between the eNBs and the SGW/PGW
should be modeled accurately.
7. It should be possible for a single UE to use different applications with different QoS profiles. Hence,
multiple EPS bearers should be supported for each
UE. This includes the necessary classification of
TCP/UDP traffic over IP done at the UE in the uplink
and at the PGW in the downlink.
8. The focus of the EPC model is mainly on the EPC
data plane. The accurate modeling of the EPC control
plane is, for the time being, not a requirement; hence,
the necessary control plane interactions can be modeled in a simplified way by leveraging on direct interaction among the different simulation objects via the
provided helper objects.
9. The focus of the EPC model is on simulations of
active users in the EPS Connection Management
(ECM) connected mode. Hence, all the functionality
that is only relevant for ECM idle mode (in particular,
tracking area update and paging) are not modeled at
all.
10. While handover support is not a current requirement, it is planned to be considered in the near future.
Hence, the management of EPS bearers by the eNBs
and the SGW/PGW should be implemented in such a
way that it can be re-used when handover support is
eventually
added.
I. INTRODUCTION
The increasing attention on the upcoming LTE mobile communication technology standardized by
3GPP, together with a shift in mobile consumer habits from voice calls only to IP-based services such as
web browsing, video streaming, video conferencing
and social networking, are causing a growing interest
by the industrial and research community into network simulator platforms that can support the evaluation of LTE networks modeling the relevant aspects
of real applications and of the TCP/IP protocol stack.
Doing this accurately means modeling not only the
LTE radio access network, but also the corresponding
core network, referred to as the Evolved Packet Core
(EPC).
II. DESIGN CRITERIA
1. The model is to be used to simulate the transmission of IP packets by the upper layers. With this respect, it shall be considered that in LTE the Scheduling and Radio Resource Management do not work
with IP packets directly, but rather with RLC PDUs,
which are obtained by segmentation and concatenation of IP packets done by the RLC entities. Hence,
these functionalities of the RLC layer should be modeled accurately.
2. The only Packet Data Network (PDN) type supported is IPv4.
3. The Serving Gateway (SGW) and PDN Gateway
(PGW) a functional entities are implemented within a
single node, which is hence referred to as the
SGW/PGW node. This choice is done to simplify the
simulation model.
4. The scenarios with inter-SGW mobility are not of
interest. Hence, a single SGW/PGW node will be
present in all simulations scenarios
5. A requirement for the EPC model is that it can be
used to simulate the end-to-end performance of realistic application models. Hence, it should be possible
to use with the EPC model any regular ns-3 application working on top of TCP or UDP.
6. Another requirement is the possibility of simulating network topologies with the presence of multiple
III. LTE-EPC ARCHITECTURE
There are two main components:
 The LTE Model: - This model includes the LTE
Radio Protocol stack (RRC, PDCP, RLC, MAC,
PHY).These entities reside entirely within the
UE and the eNB nodes.
 The EPC model: - This model includes core
network interfaces, protocols and entities. These
entities and protocols reside within the SGW,
PGW and MME nodes and partially within the
eNB nodes.
International Conference on Electronics and Communication Engineering, 28th April-2013, Bengaluru, ISBN: 978-93-83060-04-7
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2. Simulation of End-To-End Ip Connectivity For Lte-Epc
For the sake of an easy explanation, we further divide
the LTE model in two separate parts. The first part is
the lower LTE radio protocol stack, which includes in
particular the PHY and the MAC layers, as well as
the Scheduler (which is commonly associated with
the MAC layer).The second part is the upper LTE
radio stack, which includes the RRC, PDCP and RLC
protocols, and is represented below.
a different eNB. By default a 10.x.y.z/30 subnet is
assigned to each point-to-point link (a/30subnet is the
smallest subnet that allows for two distinct host addresses). To begin with, we consider the case of the
downlink; Downlink IPv4 packets are generated from
a generic remote host, and addressed to one of the UE
devices. Internet routing will take care of forwarding
the packet to the generic Net Device of the
SGW/PGW node which is connected to the internet
(this is the Gi interface according to 3GPP terminology). It determines the eNB node to which the UE is
attached, by looking at the IP destination address
(which is the address of the UE). It classifies the
packet using Traffic Flow Templates (TFTs) to identify to which EPS Bearer it belongs. EPS bearers have
a one-to-one mapping to S1-U Bearers, so this operation returns the GTP-U Tunnel End-point Identifier
(TEID) to which the packet belongs. It adds the corresponding GTP-U protocol header to the packet.
Finally, it sends the packet over an UDP socket to the
S1-U point-to-point NetDevice, addressed to the eNB
to which the UE is attached. The local delivery
process will forward the packet, via an UDP socket,
to a dedicated application called EpcEnbApplication.
This application then performs the following operations:
 It removes the GTP header and retrieves the
TEID which is contained in it.
 Leveraging on the one-to-one mapping between
S1-U bearers and Radio Bearers (which is a
3GPP requirement), it determines the Radio
Bearer ID (RBID) to which the packet belongs.
 It records the RBID in a dedicated tag called
LteRadioBearerTag, which is added to the
packet.
Figure 3.1 PROPOSED ARCHITECTURE

 It forwards the packet to the LTE EnbNetDevices of
the eNB node via a raw packet socket. Note that, at
this point, the outmost header of the packet is the
end-to-end IP header, since the IP/UDP/GTP headers
Figure 3.2 ARCHITECTURE OF THE UPPER LTE RADIO
of the S1 protocol stack has already been stripped.
STACK
Finally, the LTEUeNetDevice of the UE will receive
the packet and delivery it locally to the IP protocol
EPC
stack, which will in turn delivery it to the application
As previously shown in Figure, there are two differof the UE, which is the end point of the downlink
ent layers of IP networking. The first one is the endcommunication.
to-end layer which provides end-to-end connectivity
to the users. This layers involves the UEs, the PGW
and the remote host (including eventual internet routers and hosts in between), but does not involve the
eNB. By default, UEs are assigned a public IPv4 address in the 7.0.0.0/8 network, and the PGW gets the
address 7.0.0.1, which is used by all UEs as the gate
way to reach the internet. This default address assignment has been chosen arbitrarily. The second
layer of IP networking is the EPC local area network.
This involves all eNB nodes and the SGW/PGW
node. This network is implemented as a set of pointto-point links that connect each eNB with the
SGW/PGW node. Thus the SGW/PGW has a set of
point-to-point devices each providing connectivity to
Figure 3.2 LTE-EPC DATA PLANE PROTOCOL STACK
International Conference on Electronics and Communication Engineering, 28th April-2013, Bengaluru, ISBN: 978-93-83060-04-7
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3. Simulation of End-To-End Ip Connectivity For Lte-Epc
IV. SIMULATION RESULTS
ACKNOWLEDGEMENT
We would like to thank Mr. Deepak Nadiga, Director
of “SOLUTT CORPORATION” for his valuable
guidance. We would also like to thank to our guide
Mrs. Deepthi raj, Lecturer at Dept. Of Telecommunication Engg, DSCE. Also we would like to thank Dr
A.R.Aswatha H.O.D of telecommunication Engineering Dayananda Sagar College and all the teachers and
friends who helped us doing this project. Thank you
all once again.
BIOGRAPHY
Miss Akshatha.H.E pursing final year Telecommunication Engineering in Dayananda Sagar college of
Engineering.
Miss Namrata katti pursuing final year Telecommunication Engineering in Dayananda Sagar college of
Engineering.
Mr.Sandeep Jainapur pursuing final year telecommunication Engineering in Dayananda Sagar college of
Engineering.
Mrs. Deepthi Raj, Lecturer at Dayananda Sagar College of engineering.
Figure 4.1 AVG BYTES/SEC V/S NODES
REFERENCES
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LTE
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http://www.steepestascent.com/
tent/default.asp? Pages=2 10.
Figure 4.2 LTE-EPC N1S1
and
con-
[2]. MimoOn,mi!Mobile, http://www.mimoon.de/pages/ Products/miMobile/, Feb. 2012.
V. CONCLUSION
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Taipei, Taiwan, May 2010.
LTE technology is being proven to meet or exceed
initial target requirements, large ecosystem of operators, vendors etc. committed to LTE.Commercial
network deployments planned 2010 and beyond. EPC
represents an efficient all-IP packet core. Supports
delivery of mobile Internet services with QoS overbroad band radio networks. Supports multiple access
technologies (all 2G/3G cellular, WiMAX, Wi-Fi
etc.) and mobility between these access networks.
LTE and EPC can cost effectively address the demands of future mobile broadband growth .LTE and
EPC can cost effectively address the demands of future mobile broadband growth.
[4]. D. Gonzalez, S. Ruiz, M. Garcia-Lozano, J. Olmos,and A.
Serra, System level evaluation of LTE networks with semi
distributed intercell interference coordination," in Proc. of
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[5]. 3GPP TS 36.321, Medium Access Control (MAC) protocol
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[6]. The
LTE-EPC
Network
Simulator
(LENA)
project,“http://iptechwiki.cttc.es/LTE-EPC Network Simulator (LENA).
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International Conference on Electronics and Communication Engineering, 28th April-2013, Bengaluru, ISBN: 978-93-83060-04-7
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