LTE is the next generation network beyond 3G that will provide significantly higher throughput and lower latency compared to 3G. It will use an all-IP architecture and OFDM and MIMO technologies to improve spectral efficiency and capacity. LTE aims to deliver 3-5 times greater capacity than advanced 3G networks, lower the cost per bit, and improve the quality of experience for users through reduced latency of around 20ms compared to 120ms for typical 3G networks. Mobile network operators have a unique opportunity to evolve their networks to LTE to capitalize on increasing demand for wireless broadband and further grow their market share.

1. White Paper
Long-Term Evolution (LTE): The vision beyond 3G
Mobile networks have enabled dramatic explosion in demand for connectivity LTE encompasses the pillars of next-
advances and changes in telecommuni- from a new generation of consumer generation networks:
cations over the last two decades, and devices tailored to those new mobile > Broadband wireless as the new access
mobile operators have grown to domi- applications. Competing technologies are reality — High-throughput, low-
nate the industry, offering their sub- already emerging to address the growing latency mobile access based on
scribers a service set as rich as their nomadic wireless broadband market space OFDM/MIMO, efficiently delivering
wireline competitors (i.e. mostly voice), and challenging the status quo. However, unicast, multicast and broadcast
plus mobility. However, with the broad- mobile operators, thanks to their incum- media.
band market success in cable, xDSL and bent position, have a unique opportunity > Convergence of technology and
Wi-Fi, the competitive landscape is to evolve their infrastructures to next- networks — A single applications
changing. generation wireless networks and capi- domain serving customers across
talize on this great opportunity to further multiple networks and devices.
Although 3G technologies deliver signif-
grow their dominant market share. Their > Intelligence at the services edge —
icantly higher bit rates than 2G tech-
decision on which technology and when Implementing policy enforcement
nologies and contribute to ARPU growth
to evolve to the higher performing next- and decisions at the network edge,
for wireless data services, there is still
generation networks will underpin their in an access-agnostic but access-aware
more opportunity for wireless operators framework.
market success.
to capitalize on the ever-increasing
demand for “wireless broadband”, even
lower latency and multi-megabit
throughput. Consequently, there is an
expanding revenue opportunity from a
growing pool of underserved consumers
that can only be satisfied with next-
generation networks. The solution is
“LTE” (3GPP Long Term Evolution),
the next-generation network beyond 3G.
In addition to enabling fixed to mobile
migrations of Internet applications such
as Voice over IP (VoIP), video streaming,
music downloading, mobile TV and
many others, LTE networks will also
provide the capacity to support an

2. Mulitmedia services/interworking Application servers
Converged
SIP Non-IMS services
services
HSS
CSCF
Access systems
PSTN
CDMA Edge Services
GSM/UMTS Aggregation
LTE
Optical IP/MPLS core
Internet
Broadband
Edge services IPI
nodes
WiFi, WiMAX Other NGN
Multiple, fast Service enablers
access systems QoS, mobility, charging, security
> Technology shift to all-IP — Specific technical requirements include: > Improved quality of experience
Simplifying and streamlining the > Low latency and high throughput (QoE) — One of the benefits
network, improving scalability and LTE/SAE will bring is a reduction in
> Efficient always-on operation, with
deployment flexibility, and enabling latency time, which will enhance the
instantaneous access to network
consistent access-aware policy behavior of time-sensitive applications,
resources
enforcement and billing. such as VoIP, thus improving the user
> Support for real-time and experience. For example, the latency
> Embedded security — A multi-layer,
non-real-time applications time, expressed as the time for a 32-
multi-vendor approach to security is
critical to ensure that security is > Flexible spectrum allocations byte Ping, is expected to reach 20 ms
endemic to the network and not just > Re-use of existing cell site (compared with 120 ms for a typical
focused on point solutions. infrastructure 3G network).
> High spectrum efficiency for unicast, Two key enabling technologies will help
These key concepts also lead to a target
multicast and broadcast data the industry meet and exceed the LTE
architecture characterized by a flat all-IP
based multi-access core network, In addition to the requirements above, performance objectives:
referred to as System Architecture there is a set of minimum performance > Orthogonal Frequency Division
Evolution (SAE). requirements defined by the 3GPP Multiplexing (OFDM) is intrinsically
Long-Term Evolution (LTE) studies. able to handle the most common
Evolved wireless access: LTE These objectives include: radio frequency (RF) distortions
without the need for complex equal-
The challenge for next-generation wire- > Increased spectral efficiency and
ization techniques, and scales easily to
less networks is to provide wireless capacity — LTE is expected to deliver
fit different bandwidth requirements.
broadband at a cost and performance three to five times greater capacity
than the most advanced current 3G > Multiple Input/Multiple Output
better than that achievable with DSL
networks. (MIMO) increases peak throughput
technologies, while maintaining seam-
by transmitting and receiving multiple
less mobility, service control and maxi- > Lower cost per bit — Increased
streams of information within the
mizing network capacity with limited spectral efficiency combined with
same spectrum. MIMO exploits the
spectrum resources. the operational benefits of an all-IP
multi-path effects typical in wireless
network will reduce the cost per bit
environments.
compared to 3G solutions.
2

3. The combined use of OFDM and deployed to extend the coverage of the customers worldwide. Nortel continues
MIMO will improve the spectral effi- cell. MIMO processing also exploits to leverage its OFDM-MIMO invest-
ciency and capacity of the wireless spatial multiplexing, allowing different ment and experience across 3GPP LTE,
network, and will prove to be a very data streams to be transmitted simulta- 3GPP2 UMB (Ultra Mobile Broadband
valuable asset in maximizing usage of neously from the different transmit - EVDO Rev C) and WiMAX to
scarce spectrum typically controlled by antennas, to increase the end-user data achieve maximum synergies across these
regulatory bodies. rate and cell capacity. In addition, when advanced wireless network product lines.
knowledge of the radio channel is avail-
OFDM is already an extremely Other key enabling technologies which
able at the transmitter (e.g. via feedback
successful access technology currently Nortel is actively researching include
information from the receiver), MIMO
deployed in a number of wireless and metamaterial antennas, cell-site cable
can also implement beam-forming to
wireline applications. These applications reduction and high-efficiency linear
further increase available data rates and
include broadcast (Digital Audio power amplifier technologies, which will
spectrum efficiency.
Broadcast or DAB, and Digital Video all contribute to lowering the total cost of
Broadcast or DVB), wireless WLAN Nortel has shown that OFDM-MIMO ownership benefiting from the OFDM-
(IEEE 802.11a and IEEE 802.11g), with beam-forming — or Spatial MIMO based LTE deployments.
WiMAX (IEEE 802.16) and wireline Division Multiple Access (SDMA) —
Asynchronous Digital Subscriber Loop can provide a higher order of magnitude Simplified architecture: SAE
(ADSL/ADSL2+). OFDM is widely capacity on the downlink than current To meet the technical and performance
accepted as the basis for the air-interface 3G deployments. Nortel has also shown requirements noted previously requires
necessary to meet the requirements for how multiple antennas could be a reduction in the number of network
next-generation mobile networks. deployed on the user equipment, an nodes involved in data processing and
especially challenging requirement with transport. A flatter network architecture
MIMO employs multiple transmit and
severe space constraints. leads to improved data latency (the
receive antennas to substantially
transmission delay between the trans-
enhance the air interface. It uses space- Nortel has been investing in OFDM
mitter sending data and the receiver
time coding of the same data stream and MIMO since 1998 in anticipation
receiving it) and better support of delay-
mapped onto multiple transmit of their adoption in mobility networks.
sensitive, interactive and real-time
antennas, which is an improvement over Since then, the company has demon-
communications.
traditional reception diversity schemes strated OFDM-MIMO commercial
where only a single transmit antenna is benefits and feasibility to more than 100
OFDM-MIMO
eNodeB
AGW
Intranets
IP
eNodeB Internet
IMS
AGW PSTN
eNodeB
eNodeB
3

4. A typical LTE/SAE network will have Convergence and Content-based charging, operator policy
two types of network elements services edge control, QoS and roaming support are
supporting the user and control planes. Key requirements focus on user quality important concepts in order to sustain
of experience, service innovation and the value of key strategic assets (e.g.
> The first is the new enhanced base
station, so called “Evolved NodeB network simplification and evolution. spectrum licenses, cell site infrastruc-
(eNodeB)” per 3GPP standards. This Specifically, these include: ture, brand) over the long term, and
enhanced BTS provides the LTE air under roaming scenarios. They also
> Service-oriented architecture contribute to improving end-user
interface and performs radio resource
supporting diverse service classes quality of experience.
management for the evolved access
system. > Content-based charging
> The second is the new Access > Operator policy control of services All-IP flat networks
GateWay (AGW). The AGW provides and networks Using IP networking as the foundation
termination of the LTE bearer. It also > End-to-end QoS for service delivery provides maximum
acts as a mobility anchor point for the flexibility, decouples the user and
> Service and network roaming support
user plane. It implements key logical control planes to simplify the network
functions including MME (Mobility > Technology co-existence
and improve scalability, and allows the
Management Entity) for the Control > Open interfaces wealth of existing IETF standards to be
Plane and SAE PDN GW (System > Scalable, evolvable network elements leveraged. Specific requirements include:
Architecture Evolution Packet Data
Network GateWay) for the User > Optimal routing of traffic
Adoption of a Service-oriented
Plane. These functions may be split Architecture (SoA) is desirable in order > IP-based transport
into separate physical nodes, to reduce the time spent from service > Seamless mobility (intra- and inter-
depending on the vendor-specific creation (or development), to deploy- Radio Access Technologies)
implementation. ment, to execution, and therefore > Simplification of the network
Comparing the functional breakdown improve service innovation. SoA facili-
with existing 3G architecture: tates cost-effectiveness and acceleration
of the time to move from conception
> Radio Network elements functions,
to execution.
such as Radio Network Controller
(RNC), are distributed between the
AGW and the enhanced BTS
(eNodeB).
> Core Network elements functions,
such as SGSN and GGSN or PDSN
(Packet Data Serving Node) and
routers are distributed mostly
towards the AGW.
Standards are expected to be 100%
finalized by end of 2008.
4

5. Security
The security challenge with IP networks
is one of the most significant factors
that slows down the further adoption of
network technologies. Operators and
enterprises recognize the clear produc-
tivity improvements and cost savings of
converging their communication tech-
nologies on a single infrastructure and
enabling universal connectivity for users.
However, they are hesitant to adopt
technologies that may compromise their
publicly promoted the advantages of Nortel will be conducting LTE trials
privacy, put their business at risk and
OFDM-MIMO to 3GPP operators, with customers during 2008 and 2009,
potentially cause significant financial loss.
which accelerated its introduction into and is on track for delivery of commer-
An end-to-end system approach to the 3GPP LTE standards. cial systems by end of 2009, in line with
security is required in next-generation the availability of initial commercial
In 2006, Nortel delivered an OFDM-
wireless networks, including: devices.
MIMO prototype solution based on the
> Platform hardening Collaborative MIMO technology and Nortel’s strategy includes early co-
> User/operator authentication, achieved a connection speed in the development partnerships with mobile
authorization and auditing uplink that was 15 times faster than chipset vendors and accelerated interop-
> Secure protocols, communication today’s fastest mobile connectivity. erability testing with device manufac-
and data storage Nortel’s original OFDM-MIMO labora- turers. This will ensure the availability
> Software and configuration integrity tory prototype, demonstrated in 2004, of a complete LTE ecosystem in align-
delivered 37 Mbps in the downlink in ment with Nortel’s network solution.
> Secure network management, control
the same bandwidth. In addition, Nortel places an emphasis
and signalling
on technology leadership and simplicity
> End-point compliance At 3GSM World Congress and CTIA in
in its LTE solution to achieve the lowest
2007, Nortel publicly demonstrated a
> Network perimeter protection and total cost of ownership for operators.
interior protection pre-standards LTE air interface supporting
video streaming and file transfers to Nortel has also made significant invest-
> Unsolicited traffic protection
multiple devices. ments in autonomous network manage-
ment systems based on Self Organizing
Nortel is leading in More recently, at Mobile World Congress
Networks, Touchless Installation and
OFDM-MIMO and CTIA 2008, Nortel was again
Autonomous RF Optimization to vastly
Nortel is engaged in numerous activities demonstrating a LIVE air LTE system,
simplify the way LTE networks will be
directed towards realization of next- with embedded advanced radio func-
deployed and managed.
generation wireless networks. tionalities to cope with the varying radio
Specifically: conditions, and showing examples of Nortel is a technology leader with a
the hyperconnected lifestyle with multiple clear vision, a proven innovation track
> Driving relevant initiatives across stan-
dards bodies: 3GPP, 3GPP2, 802.16e devices running advanced multimedia record, and a commitment to best-in-
applications like High Definition video class solutions. Nortel is in a unique
> Partnerships for ecosystem
streaming, Microsoft Unified Communi- position to provide a balanced vision
development
cations, Social Networking applications on the technological landscape and its
> Terminal certification and Video Collaboration to name a few. evolution, leveraging its experience and
> Open interfaces Nortel also announced in April 2008 leadership in major wireless technolo-
that LTE calls at high vehicular speeds gies, as well as in the optical, IP, MPLS
Nortel views OFDM and MIMO as
had been made, achieving download and VoIP markets.
the fundamental building blocks for all
speeds over 50 Mbps at 110 Kmph,
future advanced wireless technologies.
during customer visits to its centre of
At 3G World Congress in 2005, Nortel
excellence in Ottawa. 5

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