396458128-LTE-Advanced.pdf

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4G
TELCOMA
LTE-Advanced

Introduction

Background
❏ There are various limitations in the design of the previous
telecommunication technologies despite of constant evolution.
❏ 3GPP again decided to evolve both the radio and core network of the
UMTS.
❏ Hence, there is a development of Long Term Evolution or LTE which is the
improvement over the UMTS.
❏ In UMTS, an air interface is specified with the carrier bandwidth of 5MHz.
(contd...)

Background
❏ Within this limit, WCDMA performed very well.
❏ There has been a decrease in the time between two transmission steps when
higher transmission speeds are attained by increasing the carrier bandwidth.
❏ The impact of multipath fading is greater on the received signal if a
transmission step is shorter.
❏ Multipath fading is observed when radio waves after striking to the object
before reaching to the receiver and split into number of copies and then
arrives at the receiver at different times.
(contd...)

Background
❏ Hence, the scattered part of signal of previous transmission step takes
longer time to reach the receiver and overlaps with the radio signal from
direct path in the current transmission step.
❏ It becomes difficult for the receiver to interpret the received signal as
overlapping is more when the transmission step is small.
❏ A different air interface has been specified with LTE that can overcome
the effect of multipath fading.
(contd...)

Background
❏ There is a use of Orthogonal Frequency Division Multiplexing (OFDM) in LTE in
which data is transmitted over number of narrowband carriers each of 180 kHz
instead of spreading one signal over the entire carrier bandwidth of 5 MHz.
❏ A data stream splits into number of slower data streams that are transmitted
simultaneously instead of only single fast transmission.
❏ As a result, in the same bandwidth, the data rate attained is similar as
compared to UMTS but longer transmission steps reduce the multipath fading
effect.
(contd...)

Background
❏ With the increase in number of narrowband carriers without any change in
the parameters for the narrowband channels, the transmission channel
gets enlarged that will increase the overall transmission speed.
❏ For LTE, there are several bandwidths from 1.25 MHz up to 20 MHz.
❏ Data rates of 100 Mbps can be achieved with a 20 MHz carrier under very
good signal conditions.
❏ The adoption of an all‐Internet Protocol (IP) approach in LTE is the major
challenge as compared to previous technologies.
(contd...)

Background
❏ An all-IP based core network is present in LTE that simplifies the design.
❏ There is a standardization of Quality of Service (QoS) mechanisms on all
interfaces.
(contd...)

LTE Advanced-Positioning in Mobile Generations
❏ Due to exponential increase in the number of mobile applications and
users, there is a need for increase in the capacity of the system which is
the main focus of the LTE network.
❏ LTE Advanced system was defined by the 3GPP release 10 and beyond in
which a set of additional features and functionalities such as wider
bandwidth and higher degree MIMO antennas are provided that will
increase the data rates and other enhancements are provided.
(contd...)

❏ Moreover, the requirements of the fourth generation IMT-Advanced
defined by ITU-R are followed by the LTE-Advanced for its evolution path.
❏ The Release 8 series of the 3GPP specifications define the basic version of
LTE that can be considered as beyond 3G, pre-4G system or 3.9G in
non-standard communications.
❏ But, all the LTE releases prior to Release 10 are not able to fulfill the
requirements of IMT-Advanced i.e. data rates of 1Gb/s.
(contd...)

❏ With the further development of LTE, a fully compliant 4G system can be
provided and is known as LTE-Advanced.
❏ 3GPP Release 10 defines this system.
❏ This system fulfills all the requirements of ITU and can be called as
ITU-compliant 4G.
(contd...)

ITU requirements for 4G systems
❏ Enhanced peak data rates: 1 Gb/s for low mobility and 100 Mb/s for high
mobility in the downlink direction
❏ Common worldwide functionality
❏ A wide range of local services and applications can be flexibly supported
in a cost-efficient way.
❏ Compatibility of service of IMT, fixed networks and other radio systems
❏ High-quality mobile services
❏ Globally used user equipment
(contd...)

ITU requirements for 4G systems
❏ User-friendly applications, services and equipment
❏ Global roaming
(contd...)

3GPP requirements for 4G systems
❏ Peak data rates of 1Gb/s in the downlink
❏ Peak data rates of 500Mb/s in the uplink
❏ Spectrum efficiency will be three times higher than the LTE system
❏ Peak spectrum efficiency of 30b/s/Hz in the downlink
❏ Peak spectrum efficiency of 15b/s/Hz in the uplink
❏ Scalable bandwidth and spectrum aggregation support
❏ Faster latency requirement from idle to connected mode transition
❏ User data throughput will be 2 times higher in the cell edge than in LTE
(contd...)

3GPP requirements for 4G systems
❏ Average user data throughput will be three times higher than in LTE
❏ Mobility performance is similat to LTE
❏ Compatible with LTE and the previous 3GPP systems
(contd...)

Motivation for LTE-Advanced Deployment
❏ The use of data service was only 2% of the total traffic during the 2G era
and in the beginning of the deployment of the 3G system.
❏ The two dominant services at that time were the circuit-switched voice
service and short message service.
❏ The level of use of data service was not even increase with the
development of packet data solutions i.e.GPRS (General Packet Radio
Service) and its developed version, EGPRS (Enhanced GPRS) or EDGE
(Enhanced Data Rates for Global Evolution).
(contd...)

❏ Due to higher data rates and lower latency provided by the recent
systems there is an increase in the level of packet data use.
❏ Hence, there is a development of other large number of applications.
❏ The growth in the penetration of the smartphone is one of the main driver
for use of future data.
❏ In the forthcoming years, the necessary capacity and data rates will be
provided by the LTE and LTE-Advanced for the end users.
(contd...)

❏ Along with the increase in the the need for the actual user data transfer,
there will be heavier load of the related signaling over time.
❏ For the smooth experiences of the user, there must be guaranteed
combined user data and signaling load that results in higher data rate and
throughput, and low latency.
(contd...)

Technologies adopted in LTE-A
❏ MU-MIMO, network MIMO, distributed antenna MIMO, multimode adaptive
MIMO: Capacity and cell coverage improvement
❏ Superposition coding: DL capacity improvement
❏ Enhancement of MBSFN: MBSFN capacity improvement
❏ Improved beamforming techniques: Capacity and cell-edge coverage
improvement
❏ Relay, remote radio equipment: Capacity and cell coverage improvement
(contd...)

❏ Wireless network coding: Capacity and cell coverage improvement
❏ Codebooks and feedback mechanism enhancements for closed loop
MIMO : CL-MIMO performance improvement
❏ Enhanced intercell interference management: Capacity and cell-edge
coverage improvement
❏ Wireless backhaul/sidehaul: Deployment constraints are simplified
❏ Home eNodeB/Femto/Picocells support: Indoor coverage extension
(contd...)

❏ SON: Network deployment and optimization simplification
❏ Homogeneous and heterogeneous networks support
❏ Enhanced intercell interference coordination support, with more
advanced evolution of CoMP
(contd...)

Principles of 4G LTE-A

Introduction
❏ 3GPP Release 10 defines the
LTE-Advanced network while
3GPP Releases 8 and 9 define
the basic LTE.
❏ Figure shows the LTE and
LTE-Advanced user
equipment functionality
principle with the networks of
LTE and LTE-Advanced. (contd...)

Introduction
❏ LTE UE (of Releases 8 and 9) supports the capabilities of both the LTE and
LTE-Advanced (Release 10 and beyond) eNodeB and are able to work
with them.
❏ There is no benefit to the LTE UE from the advanced capabilities of
eNodeB LTE-A.
❏ Similarly, LTE-A UE works with the eNodeBs of LTE and LTE-A but the
performance of LTE-A can not be achieved with the eNodeB of LTE.
(contd...)

Introduction
❏ Hence, there is a backward compatibility of LTE-A with LTE.
❏ Therefore, the deployment of network becomes easy and the
straightforward migration is provided from LTE.
❏ Higher data rate and capacity mobile broadband access has been
provided by LTE-A, the basic LTE 20 MHz band can be extended upto 100
MHz and depending on the set of functionalities theoretical 200 Mbps
data rate of LTE is enhanced upto 1-3 Gbps.
(contd...)

LTE and SAE Standardization
❏ Release 8, the basis for LTE: The basic functionality for, self-configuration
plug and play, neighbor cell relation and auto cell ID, and Inter Cell
Interference Coordination (ISIC) are contained.
❏ Release 9, addition of minor functionalities in LTE, and the ITU-R
compliant 4G of Release 10 LTE-A requirements are also added:
Functionalities of load balancing and energy saving, handover and RACH
optimization are contained.
(contd...)

LTE and SAE Standardization
❏ Release 10, addition of major performance parameters, the basis for
LTE-Advanced. Contains coverage and capacity optimization
enhancements.
❏ Release 11 and beyond, further enhancements for LTE-Advanced.
(contd...)

Evolution path of 3GPP
❏ There has been an evolution of the systems of 3GPP since the first GSM
systems upto LTE/SAE.
❏ There is a flat architecture of Release 8 of 3GPP.
❏ This means that one element type each for radio and core network are
there, which is the case for Release 10 (LTE-Advanced) also.
❏ The main focus of LTE/SAE standardization is to improve the data rates
and response times of signalling and lower the cost as compared to that
provided by GSM and UMTS/HSPA.
(contd...)

❏ There is a need for latency and round-trip delay minimization in order to
provide higher TCP traffic throughput and reduce UDP/RTP traffic jitter so
that real-time services are provided with higher quality.
❏ Due to these benefits, the awareness of LTE has increased and also the
use of the networks has increased.
❏ Also there is an exponential increase in the number of subscribers using
the Internet services.
(contd...)

❏ Hence the reduction of latency of signalling or control plane messaging is
essential for fluent user experience.
❏ One of the major limiting factor in providing the fluent services is the
round trip delay.
❏ The main advantage of all IP-based architecture of the mobile network is
the possibility of functionality simplification.
❏ The reduction of the elements of network is the basic principle of IP
networks.
(contd...)

❏ Hence, the packet switched domain is used to deliver the data in the EPC.
❏ There is a backward compatibility of LTE/SAE with the previous CS
domain network services by using the mechanisms that support the
service continuity.
❏ The mobility mechanisms for EPC and EPS are provided in case the
terminals are attached in 2G, 3G and LTE networks.
❏ GTP and PMIP mobility protocols are used for mobility.
(contd...)

LTE-Advanced has several features i.e.
a. Increased peak data rate 3 Gb/s for DL and 1.5 Gb/s for UL.
b. Higher spectral efficiency, from a maximum of 16b/s/Hz in Release 8
to 30 b/s/Hz in Release 10.
c. The number of simultaneously active subscribers has increased.
d. The performance at cell edges has increased. The value should be at
least 2.40 b/s/Hz/cell for DL 2 × 2 MIMO.
(contd...)

The major means to achieve the performance of LTE-Advanced are:
a. Carrier Aggregation (CA)
b. MIMO enhancements
c. Relays
d. CoMP
e. HetNet enhancements (eICIC, feICIC)
(contd...)

Various enhancements in the performance of LTE-A are:
a. Self-Organizing/Optimizing Network (SON) evolution
b. IMS Service Continuity (ISC)
c. IMS Centralized Services (ICS)
d. Home eNodeB, LIPA, SIPTO
e. Fixed Mobile Convergence (FMC)
f. Machine to Machine (MTM) communications
g. SVRCC (contd...)

h. Wi-Fi Inter-working
i. UICC
j. eMBMS
k. Non-Voice Emergency Services
(contd...)

LTE-A Spectrum Allocation
❏ The currently used band for GSM i.e. the 1800 MHz Band 3 can be used in
43% of all the deployments.
❏ The one of the most popular band for the LTE deployments is 2600 MHz
Band 7 that can be used in 27% of the deployments.
❏ The band used for the analog TV broadcast networks i.e. 700 MHz can be
used for the LTE deployment.
(contd...)

LTE-A Spectrum Allocation
❏ In 13% of deployments, the 800 MHz band 20 is used.
❏ 9% of the world’s deployments can be represented by the AWS band 4.
(contd...)

LTE-A Data Performance
❏ Figure shows the theoretical
peak and average data rates
of LTE Release 8 in downlink.
(contd...)

❏ Figure shows the theoretical
peak and average data rates
of LTE Release 8 in uplink.
❏ It is observed from these two
figures that under ideal
conditions, Release 8 LTE
network can provide the
maximum theoretical peak
data rates of cell per TTI. (contd...)

❏ The improved spectral efficiency helps to provide the highest data rates in
the 20 MHz bandwidth as compared to the previous systems.
❏ The available capacity in the dimensioning of the network depends on the
overhead.
❏ There can be 50% overhead for small packets, 25% for medium-sized and
large packets.
❏ PDCP and RLC are responsible for the radio interface overhead.
(contd...)

LTE UE Requirements

Delay Requirements for Backhaul
❏ The services demanded and consumed by the users are used to
determine the QoS requirements of the transport network.
❏ For interactivity and for the response time, the delay requirements are
given.
❏ For TCP based connection, the throughput performance is given by the
delay requirements.
❏ In the S1 and X2 interfaces, for the handover and ANR, the delay
requirements that are set by the radio network layer protocols are given.
(contd...)

❏ The principle of handover of
LTE/LTE-A is shown in the
figure.
❏ There can be a
recommendation of packet
delay to be equal to or less
than 10 ms.
(contd...)

❏ There can be a recommendation of packet delay variation to be equal to
or less than ±5 ms.
❏ There can be a recommendation of packet loss ratio to be equal to or less
than 10^-4.
(contd...)

4G LTE-A Architecture

Introduction
❏ Radio and core networks are consisted in the evolved 3GPP system.
❏ More uniform user experiences are provided and the network capacity is
increased by bringing the network closer to the user which is the main aim of
the LTE-A.
❏ LTE-Advanced is based on advanced topology networks with increased
capacity and performance in order to achieve this goal
❏ This type of self-organized network allows minimization of the attempts at
drive testing, and the optimal initial set-up and operational mode can be
assured. (contd...)

Introduction
❏ The intelligent node association is consisted in these networks in which
relays, adaptive resource allocation and multicarrier functionality, as well
as coordinated beamforming can be supported.
❏ More efficient and uniform performance is given by the network with the
help of femto cells and relays.
❏ Higher quality of service level is provided by this advanced topology
networks to the end users.
(contd...)

Introduction
❏ The high performance and capacity of Release 10 and beyond networks can
be created by using the enhanced topology boosters in order to meet the
IMT-Advanced requirements of ITU.
❏ To overcome the theoretical limits of the radio link performance along with
the performance of LTE-A, the actual network topology can be enhanced.
❏ This can be achieved by HetNets whose aim is to improve the spectral
efficiency in a given area.
❏ A mix of macro, pico, femto and relay base stations gives the HetNets.
(contd...)

Main elements of LTE/EPC
❏ The LTE part refers to the
E-UTRAN, while EPC means
the evolved packet core
network in the LTE/EPC
network.
❏ The division is clarified in the
figure.
(contd...)

❏ Figure shows the difference
between the 3GPP 3G
architectural concept of the core
solutions.
❏ There was not any change in the
principle of the core since Release
8, so there is a continuation of the
basic functionality and role of the
network elements in the LTE-A
phase. (contd...)

❏ There is a re-dimensioning of the performance figures of the elements
along with the higher data rates of Release 10 so that unbalanced
bottlenecks on the core side can not be created.
❏ The additional services such as advanced eMBMS and Wi-Fi Offloading
can also be provided by the LTE-A phase
❏ The additional elements and capacity dimensioning is required for the
overall development of the IMS.
(contd...)

LTE-A Network Architecture
❏ The architecture of LTE-Advanced
E-UTRAN can be shown in the
figure.
❏ There is a single element in the
E-UTRAN in the Releases 8 and 9
i.e. enhanced e-NodeB.
❏ The radio interface is included in it
in which the user and control
plane protocol terminations are
contained towards the UE. (contd...)

❏ One or various E-UTRAN cells are served by each eNodeB element and
hence acts as a logical function.
❏ X2 interface is used to interconnect the elements of eNodeB.
❏ For localized coverage improvement, the elements of eNodeB are used
which are low-cost elements and their connection to EPC can be direct or
via a gateway.
❏ The separate gateway supports the large number of HeNBs.
(contd...)

❏ The relay nodes and advanced relaying strategies are deployed in LTE-S so
that the network performance can be enhanced.
❏ The main focus of the elements of the relays and HeNodeB is the coverage,
data rate, and QoS performance improvement.
❏ The plane Packet Data Convergence Protocol (PDCP), Radio Link Control
(RLC), Medium Access Control (MAC) and the Physical Layer (PHY) protocol
are included in the protocol stacks of LTE-A.
❏ The Radio Resource Control (RRC) protocols are consisted in control plane.
(contd...)

LTE-A eNodeB
❏ The eNB element of LTE is responsible for the transmission and reception
of radio with the UE.
❏ The needed functionality is provided by eNB for RRM.
❏ The care of the ciphering and header compression has been taken by eNB
over the air interface.
❏ The following tasks can be handled by eNB element:
❏ Radio Resource Management (RRM)
❏ Radio Bearer Control
(contd...)

LTE-A eNodeB
❏ Radio Admission Control
❏ Connection Mobility Control
❏ UE scheduling (DL and UL).
❏ Security in Access Stratum (AS).
❏ Measurements as a basis for the scheduling and mobility
management.
❏ IP header compression.
❏ Encryption of the user data.
(contd...)

LTE-A eNodeB
❏ Routing of the user data between eNB and S-GW.
❏ Paging handling that originates from MME.
❏ Handling of the broadcast messaging that originates from MME and
the Operations and Management System (OMS).
❏ The MME element selection
❏ PWS messages handling, including ETWS and CMAS.
(contd...)

LTE-A eNodeB
❏ The following are the specific aspects for the HeNB:
❏ The equipment used on the premises of the customers is HeNB in
which spectrum of licensed operator is used.
❏ The network coverage and capacity can be enhanced using HeNB.
❏ All the eNB functionalities are included in HeNB.
(contd...)

LTE-A eNodeB
❏ The principle of the HeNB
concept is shown in the figure.
(contd...)

LTE-A eNodeB
❏ The following access scenarios use the HeNB concept:
❏ The respective HeNB can only be accessed by the pre-defined
Closed Subscriber Group (CSG) members in the closed access mode.
❏ The HeNB can be accessed by both the both members and
non-members of the closed subscriber group in the hybrid access
mode but the priority is given to members over non-members.
❏ The members and non-members see the HeNB as a normal eNB in
the open access mode.
(contd...)

LTE-A eNodeB
❏ The most important additions in radio access are:
❏ Inbound Mobility.
❏ Access Control.
❏ New Hybrid Cell concept.
❏ Management of out-of-date CSG info.
❏ Operation, Administration and Maintenance for HeNB elements.
❏ Operator-controlled CSG list.
❏ RF Requirements for TDD and FDD HeNBs.
(contd...)

LTE-A S-GW
❏ The Serving Gateway (S-GW) element is used to route and forward the data
packets of the user.
❏ The mobility anchoring of the user plane can also be managed by the S-GW
during inter-eNB handovers.
❏ By relaying the traffic between P-GW and other 2G/3G systems, it acts as a
mobility anchor between LTE and other 3GPP technologies via the terminating
S4-interface.
❏ Paging can be triggered by S-GW when data is received by UE in idle mode.
(contd...)

LTE-A S-GW
❏ The UE contexts are also managed by the S-GW.
❏ The user plane connectivity is provided by S-GW with UE on one side and
P-GW on the other side.
❏ These elements can be separated or combined as a single element
depending on the approach of the network provider.
(contd...)

LTE-A S-GW
❏ The following functionalities are controlled by the S-GW:
❏ For the inter-eNB handover procedure, the local anchor point is S-GW.
❏ For the inter-3GPP network mobility, S-GW is an anchor point.
❏ Lawful Interception (LI)
❏ Routing and forwarding of packets
❏ The packet buffering is made by S-GW in the E-UTRAN idle mode
❏ The network-initiated/triggered service request procedure is handled by
S-GW
(contd...)

LTE-A S-GW
❏ Packet marking in the transport level for both DL and UL
❏ Collection of charging Data Record (CDR) to identify the UE, PDN and
QCI.
❏ User accounting and granularity of QCI for the inter-operator charging
processes.
(contd...)

LTE-A P-GW
❏ The connectivity between the UE and the external packet data networks is
provided by the Packet Data Network Gateway (PDN-GW, or P-GW) as it
acts as an interface between the SAE network and external networks.
❏ The main role of P-GW is to act as the anchor for mobility between 3GPP
and non-3GPP technologies.
❏ In order to access various PDNs in parallel, a single UE can be connected
to more than one P-GW at a time .
(contd...)

LTE-A P-GW
❏ The following functionalities are included in the P-GW:
❏ Allocation of IP address of the user
❏ Packet filtering
❏ Lawful Interception (LI)
❏ Packet marking in the transport level in DL only.
❏ Service-level charging, gating and rate enforcement
❏ Online charging credit control
(contd...)

LTE-A MME
❏ The user equipment tracking and paging procedures are managed by the
mobility management equipment (MME) in the idle mode.
❏ The bearer activation and deactivation procedures are controlled by the
MME by selecting adequate S-GW during the initial attach procedure of
UE.
(contd...)

LTE-A MME
❏ The following functionalities are handled by the MME:
❏ Signaling in the Non Access Stratum (NAS)
❏ Security of the NAS signaling
❏ AS security control
❏ The selection of the P-GW and S-GW
❏ The selection of other MMEs during handover
❏ The selection of SGSN during handovers between LTE and 3GPP
2G/3G access networks
(contd...)

LTE-A MME
❏ Signaling of mobility of inter-CN node between different 3GPP 2G/3G
access networks
❏ Tracking Area (TA) lists management
❏ International and national roaming
❏ Authentication of user
❏ Bearer establishment and management
❏ PWS message transmission support
❏ The paging retransmission management of UE
(contd...)

LTE-A MME
❏ Management of other functions to search UE in the idle state
❏ The temporary identities generation and allocation for UE
❏ The UE authorization for camping on PLMN
❏ The UE roaming restrictions enforcement
❏ The provision of the mobility control plane function between LTE and
the 2G/3G access networks via the S3 interface towards SGSN
(contd...)

Femto Cell Architecture
❏ The femto cell is a small mobile communications base station.
❏ It is designed for a home or small business environment that provides
coverage to area of tens of meters.
❏ Broadband connectivity is used to connect it to the network of the service
provider.
❏ Two to four active mobile devices are supported in a home environment
and 8–16 active mobile devices are supported in a business environment.
(contd...)

Femto Cell Architecture
❏ The femto cell architecture is
shown in the figure.
❏ The extended radio coverage
indoors is the main benefit of the
femto cell.
❏ There can be a positive impact on
the duration of the battery life
along with the lower levels of the
output power of the user devices
due to enhanced coverage. (contd...)

The Uu Interface
❏ The LTE radio interface defined between the eNodeB and UE is LTE-Uu.
❏ PS connectivity is provided by the eNodeB in such a way that there is an
integration of previous 3G RNC functionality into the eNodeB.
❏ Due to this flat architecture there is no need for separate RNC equipment.
(contd...)

The X2 Interface
❏ The connection between the eNodeBs is defined by the X2 interface.
❏ It is required for the intereNodeB handover procedures and forwarding of
the data, as well as to provide the inter-cell radio resource management
signaling and interface management signaling.
❏ Load information to the neighboring eNBs is provided by this interface to
manage RRM interference.
(contd...)

The S1 Interface
❏ There are two reference points of S1 interface i.e. S1-MME and S1-U.
❏ The eNodeB and MME can be connected by using S1-MME and the eNB
and S-GW are connected using the S1-U interface.
❏ For the control plane signaling between the eNB and MME, S1-MME
reference point is defined.
❏ The eRANAP protocol is used over this reference point and the Stream
Control Transmission Protocol (SCTP) is used.
(contd...)

The S1 Interface
❏ Between the eNodeB and S-GW, the S1-U reference point is defined to
carry the user plane data.
(contd...)

The S2a Interface
❏ The user plane between a trusted non-3GPP IP access and the gateway is
provided by S2a interface that includes the control and mobility support.
❏ It is based on the Proxy Mobile IP.
❏ The Client Mobile IPv4 FA mode support can be included in S2a so that
access via trusted non-3GPP IP access can be enabled when the PMIP is
not available.
(contd...)

The S2b Interface
❏ The user plane between ePDG and PGW is provided by the S2b interface
that includes control and mobility support.
❏ It is based on the Proxy Mobile IP.
(contd...)

The S2c Interface
❏ The user plane between the UE and the P-GW is provided by the S2c
interface that includes control and mobility support.
❏ It can be implemented over trusted or non-trusted 3GPP access as well as
over non-3GPP access.
❏ It is based on the Client Mobile IP co-located mode.
(contd...)

Other Interfaces
❏ The S3 Interface
❏ The signaling between the MME and SGSN is provided by the S3
interface.
❏ It is based on the Gn reference.
❏ The signaling between the S-GW and SGSN is provided by this interface.
❏ In the user plane, a GTP-based tunnel is provided by this during the
intersystem handover.
❏ It is based on the Gn reference. (contd...)

Other Interfaces
❏ The signaling between the S-GW and P-GW is provided by this interface.
❏ The user plane tunneling and its management is provided by S5.
❏ The S6a Interface
❏ The subscription and authentication data can be carried between the HSS
(Home Subscriber Server) and the MME by using S6a interface.
❏ For authentication and authorization procedures in the user access to the
evolved system, the transfer of subscription and authentication related data
can be enabled by using S6a.
(contd...)

Other Interfaces
❏ The policy and charging rules originating from the Policy and Charging
Rules Function (PCRF) are transferred to the Policy and Charging
Enforcement Function (PCEF) of P-GW by using S7 interface.
❏ The signaling between MMEs is provided by the S10 interface.
❏ MME relocation and transfer of information between MMEs is done by this
interface.
(contd...)

Other Interfaces
❏ The signaling messages between the S-GW and MME are handled by it.
❏ The SGi Interface
❏ The signaling between PGW and PDN is handled by this interface.
❏ SGi functions in the same way as the Gi interface for 2G/3G access.
❏ The Gn/Gp Interface
❏ In EPS, the connection to the packet data networks can be created using
this interface.
(contd...)

4G LTE-A Protocol Layers

Protocol Stacks
❏ There are user and control
planes of protocol stacks
between different elements.
❏ Figure shows the role of each
layer of the protocol.
(contd...)

Channels
❏ There are basically three types
of channels
❏ Logical channels
❏ Transport channels
❏ Physical channels
❏ The LTE/LTE-A transport
channels are differentiated on
the basis of the data
transmission characteristics. (contd...)

Channels
❏ MAC protocol layer is used to
map the logical and transport
channels in which the UL and
DL scheduling of the UE and
its services can be managed.
❏ The format of transport can
also be selected by the MAC
layer.
(contd...)

Channels
❏ The logical channels are
characterized by the data
transferred by them.
(contd...)

Channels
❏ The figure shows the mapping
of the logical channels to the
transport channels.
❏ The layer 2 of LTE-A is divided
into Medium Access Control
(MAC), Radio Link Control
(RLC) and Packet Data
Convergence Protocol (PDCP).
(contd...)

User Plane
❏ The figure shows the user
plane protocol stack structure
between the UE, eNB, S-GW
and P-GW.
(contd...)

User Plane
❏ In the case of direct
communications between two
eNBs the user plane is defined
as shown in Figure.
(contd...)

User Plane
❏ The following are the functions of entities of user plane:
❏ The functions of MAC are mapping between the logical and transport
channels, multiplexing and de-multiplexing, reporting of the
scheduling information, HARQ functions, priority handling and
transport format selection.
❏ The ARQ functions, segmentation concatenation, re-segmentation
concatenation, in-sequence delivery, duplicate packets detection and
reestablishment is performed by RLC.
(contd...)

User Plane
❏ The ciphering of the user and control plane, header compression
(ROCH), in-sequence delivery of the upper layer packet data units
(PDU), duplicate elimination of the lower layer SDUs, integrity
protection for the control plane, and timer-based discarding is
provided by PDCP.
(contd...)

Control Plane
❏ Figure shows the protocol
stack structure of control
plane.
(contd...)

Layer 1
❏ The physical layer is described as the LTE/SAE radio protocol layer 1.
❏ The means and basic functionality of delivering the bits over the air
interface in DL and UL is provided by this layer.
❏ Two separate access techniques are used by the radio interface of LTE:
❏ OFDMA (Orthogonal Frequency Division Multiple Access) in the DL
❏ SC-FDMA (Single Carrier Frequency Division Multiple Access) in the
UL
❏ For the signaling and data delivery, number of channels are defined.
(contd...)

Layer 1
❏ In LTE, there are simplified channel definitions as compared to the
previous 3G UMTS technology including the dedicated channels removal.
❏ For the signaling and data delivery, shared channels are used.
❏ There is a dynamic mapping of the physical channels to the resources in
LTE which is done by using scheduler.
❏ The transport channels are used to communicate with and handle the
data transmission with higher layers by the physical layer by taking care of
the bit rate, delays, collisions and reliability of the transmission.
(contd...)

Layer 2
❏ MAC
❏ It is the lowest protocol in layer 2.
❏ The management of transport channels is the main function of this
layer.
❏ The logical channel’s data has been multiplexed onto the transmission
of the transport channels by using MAC and then at reception it
demultiplexes it according to the logical channels priority level.
❏ MAC includes the HARQ, collision handling and UE identification.
(contd...)

Layer 2
❏ RLC
❏ The next protocol to MAC is RLC in layer 2.
❏ Each Radio Bearer and RLC instance has one-to-one relationship.
❏ The radio bearer quality can be enhanced by the RLC via ARQ with
the use of the data frames in which sequence identities are contained
and via the status reports so that the retransmission mechanism can
be triggered.
(contd...)

Layer 2
❏ The data has been segmented and reassembled by RLC to suit the
data of higher layer.
❏ The higher layer data pieces can be concatenated into blocks that can
be transported over the transport channels by allowing limited
transport block sizes.
(contd...)

Layer 3
❏ PDCP
❏ It is used by each radio bearer.
❏ The header compression is managed by PDCP that is known as ROHC
(Robust Header Compression).
❏ The ciphering and deciphering functionalities are also managed by PDCP.
❏ The header compression is useful for the delivery of IP datagram but not
for signaling.
❏ Hence, for signaling, the ciphering and deciphering is done by using PDCP
without header compression.
(contd...)

Layer 3
❏ RRC
❏ In E-UTRAN, the access stratum-specific control protocol is RRC.
❏ The required messages for the channel management, measurement
control, and reporting are provided by this protocol.
❏ It’s control plane is multi-task entity that controls broadcast and
paging procedures, RRC connection set-up, radio bearer control,
mobility functions and LTE-UE measurement control.
(contd...)

Layer 3
❏ NAS Protocols
❏ The protocol runs between UE and MME is NAS protocol.
❏ It is placed on the top of RRC by which the required carrier messages
for the NAS transfer are provided.
❏ Authentication procedure, security control, EPS bearer management,
EMC_Idle mobility handling, and paging origination in the EMC_Idle
state are some of the important tasks of NAS.
(contd...)

4G LTE-A Core Network

Evolution of Core Network of LTE/LTE-A
❏ The same principles that are defined for LTE Releases 8 and 9 are used to
design the core network of LTE-A.
❏ But the dimensioning of the infrastructure of core network is done in such
a way that bottlenecks can not be created due to the increased data rates
of the radio interface.
❏ The dimensioning of the backhaul portions can also be done to avoid
bottlenecks.
(contd...)

❏ The intermediate links between the core network and the sub-networks at
the edge of the network are referred to as backhaul.
❏ The wireless backhaul is provided in the LTE-A by employing layer 3 relay.
❏ Hence, the relay transmission has been provided between eNodeB and
UE so that radio coverage in the planned environments can be extended.
❏ By considering the maximum and average data rates of the radio
interface, the dimensioning of the core network can be balanced.
(contd...)

❏ The average load can be estimated by analyzing the spectral efficiency as
a function of the distance from the eNodeB, the licensed spectrum share,
the number of sectors on average, the speed of UE and the number of
subscribers.
❏ The expected bandwidth requirement during the initial phase of
commissioning and deployment of LTE site can be typically below 100
Mbps.
(contd...)

❏ High scalability is required from the IP core and backhaul networks to
support lower data system at the same time as high data rates of
LTE/LTE-A.
❏ The circuit-switched TDM is the traditional solution for the backhaul either
via T1 or E1.
❏ The fiber optics or microwave radio links perform backhauling between
the cellular system elements.
(contd...)

Evolution of Core
Network of LTE/LTE-A
❏ Figure shows the convergence
of the backhaul for 2G, 3G and
LTE/LTE-A.
(contd...)

LTE Transport Protocol Stack
❏ The LTE/SAE network’s solution is based on the protocol stacks of IPv4
for the user, control and management planes.
❏ In order to drive the evolution path towards the evolved IP solutions, IPv6
can also be supported by the LTE.
(contd...)

Ethernet Transport
❏ The electrical and optical Ethernet interfaces are included in the basic
solution of LTE/SAE so that the lowest transport cost and high transport
capacity is provided to the operator.
❏ A Gigabit Ethernet 100/1000Base-T with electrical connectivity is the
physical solution with optical connectivity via the RJ-45 standard and
1000Base-SX/LX/ZX.
(contd...)

Ethernet Transport
❏ The automatic negotiation of
the mode and data rate is the
logical functionality of
LTE/SAE.
❏ The protocol stacks of the
Ethernet solution is shown in
the figure.
(contd...)

IP Address Differentiation
❏ A different IP address is provided by this solution for each of the LTE/SAE planes.
❏ Either interface addresses or virtual addresses can be used by the eNodeB
applications.
❏ There is a sharing of the single address between all the planes in the address
sharing option.
❏ Separate addresses are used by each plane in the multiple interface address
solution.
❏ The separate, virtual addresses of each plane to which applications are bound to in
the virtual address allocation.
(contd...)

Traffic Prioritization on IP Layer
❏ The reliable system control is ensured by this functionality so that
different user service classes are supported by it.
❏ There may be configuration of the DiffServ Code Points (DSCP) and on the
basis of the QCI of the associated EPS bearer the user plane DSCPs are
configurable.
(contd...)

Traffic Prioritization on Ethernet Layer
❏ The quality of service is ensured by this service if the transport network is
not QoS-aware in IP domain.
❏ The use Ethernet priority bits is one of the way of accessing this functionin
the Ethernet layer.
(contd...)

VLAN Based Traffic Differentiation
❏ The virtually separated networks are supported by this functionality for all
the planes.
❏ Hence, the VLAN identities can be configured for this functionality.
(contd...)

IPSec
❏ The security of the transport depends on this functionality.
❏ All the planes over the transport network support IPSec.
(contd...)

Synchronization
❏ Use of GPS is a straightforward and practical solution to synchronization.
❏ Both frequency and phase synchronization are supported by GPS.
❏ The maximum length of the data and power cable arises the practical
limitations.
❏ The synchronization interface down to the eNodeB if there is integration of
GPS receiver into the antenna.
❏ There is an installation of a surge protector between the GPS antenna and the
receiver and system module so that the damage due to thunderstorms can be
minimised. (contd...)

Synchronization
❏ The 2.048 MHz signal of the TDM infrastructure carries the synchronization
also and this signal is provided by the co-located equipment.
❏ The PDH interfaces also provide the synchronization.
(contd...)

Timing Over Packet
❏ Timing over packet (ToP) is an advanced method of synchronization that uses
the Ethernet interface to provide synchronization.
❏ A ToP Grandmaster, that is the root source of the synchronization data
delivered for the eNodeB over the IP/Ethernet network, is contained in the
solution.
❏ The ToP Grandmaster is connected to the reference clock and the clock
signal is recovered by the eNodeB over the Ethernet via a ToP slave.
❏ The high-quality packet data network is the requirement for this type of
synchronization. (contd...)

Synchronous Ethernet
❏ The synchronous Ethernet concept is another method of synchronization.
❏ Hence, accurate frequency synchronization has been provided over the
Ethernet links such that the accuracy is independ on the network load.
❏ An SDH is applied to distribute the frequency via layer 1 by using this
functionality.
❏ This solution is implemented in all the nodes of the synchronization path
which is its biggest challenge.
(contd...)

Transport Network
❏ The transport network for LTE should be designed in such a way that the
increased maximum radio interface data rates canbe supported by it.
❏ Hence, re-dimensioning of the existing backhaul, aggregation and
backbone networks is needed so that enhanced capacity can be supplied
by the new hardware to guarantee the delivery of the data from the radio
network to SAE and then to the PDNs.
❏ The packet data can also be supported via the Ethernet connectivity by
updating the TDM connectivity based traditional operator backhaul.
(contd...)

Transport Network
❏ The already existing infrastructure enhances fluently by employing this type
of hybrid backhaul network.
❏ The connectivity between the eNB elements and the MME and S-GW of EPC.
❏ The connectivity between the 2G BTS and 3G NodeB to the BSC and RNC,
respectively is provided by combining the TDM and the Ethernet.
❏ The Carrier Ethernet Transport together with a pseudo wire transport is used
to deliver the LTE traffic and traffic of 2G BTS and NodeB of WCDMA and
HSPA over the IP packet infrastructure.
(contd...)

Transport Network
❏ Carrier Ethernet Transport
❏ To deploy new backhaul networks, the Carrier Ethernet Transport
(CET) technology is used.
❏ For emulation of TDM and ATM pseudo wire solutions can be applied
to provide connectivity if native solutions are unavailable.
(contd...)

Transport Network
❏ Figure shows CET
example.
❏ The traditional time
division multiplex (TDM)
transport solutions such as
SDH/PDH can be replaced
by the cost-effective
solution which is called
CET concept. (contd...)

Transport Network
❏ The packet-based backhaul infrastructure is used to deliver all of the
traffic of the LTE, 3G and 2G.
❏ The CET solution has following benefits:
❏ standardized services support in a variety of physical
infrastructures.
❏ Bandwidth scalability
❏ Highly reliable
❏ The Quality of Service options support
(contd...)

Transport Network
❏ The network can be monitored, diagnosed and managed by using this
concept in a centralized way.
❏ Transport for S1-U Interface
❏ The access network, the aggregation networks and the MPLS
(Multi-Protocol Label Switching) backbone network are included in
the network between the eNodeBs as well as between the eNodeB
and the S-GW.
(contd...)

Transport Network
❏ There is a use of microwave radio links within the access network so
that wireless interconnection can be provided in the areas where fiber
optics are unavailable.
❏ Hence, the handovers between eNodeBs can be designed in such a
way that a sufficiently high capacity and low delays are offered.
❏ There are various Virtual Local Area Network (VLAN) partitions in the
access network of the LTE/LTE-A such that one or more eNodeBs are
contained in each partition.
(contd...)

Transport Network
❏ Figure shows the traffic
delivery between LTE eNB
elements and S-GW.
❏ The combination of a ring
topology with a Virtual
Private LAN Service
transport (VPLS) is applied
to design the aggregation
network of LTE. (contd...)

Transport Network
❏ VPLS is based on the concept of MPLS backbone.
❏ A single Label Switch Path (LSP) is reserved by the aggregation
network to VLAN with the access network of the LTE.
❏ The option for the actual MPLS backbone network which is connected
to S-GW and is based on the routers of layer 3 of mesh topology is
❏ In this MPLS network, LSP is used for delivering the IP data traffic
between the aggregation network and S-GW.
(contd...)

Core Network
❏ The use of a common packet
core concept is the logical
solution for the multiple radio
access technologies.
❏ The definition of the S4 interface
between the SGSN and Serving
Gateway network entities
increases the possibility of this
concept.
(contd...)

Core Network
❏ An optimized interworking functionality and Quality of Service handling
between the LTE network and the non-LTE access networks is provided
by the common core.
❏ Both LTE and 2G/3G bearers can be handled by it.
❏ A common interface is provided with the Home Subscriber Server (HSS).
(contd...)

Core Network
❏ The idea of common core is
shown in figure.
(contd...)

IMS Architecture
❏ It is home network centric which consists of many different entities that
can be collocated or distributed within the network.
❏ There are number of main elements into which IMS network architecture
can be splitted i.e. user equipment, access network, core network, and
application layer.
(contd...)

IMS Architecture
❏ Figure shows the IMS
architecture.
(contd...)

Proxy Call State Control Function
❏ It is the first point in either the home or visited network where access to
IMS network is provided the end user terminal and acts as the SIP proxy.
❏ It is responsible for:
❏ Providing sufficient security measures
❏ Handling the resource reservations
❏ It is used to pass the registration signalling to register with the IMS
network.
❏ It acts as the codec negotiation between the intended SIP endpoints.
(contd...)

Interrogating Call State Control Function
❏ The first point of contact is I-CSCF in the IMS network which acts as the
SIP proxy.
❏ The requests to the correct Serving Call State Control Function are
enabled by it.
❏ 3GPP standardized Session Initiation Protocol (SIP) is used to provide the
Interface between the P-CSCF and the I-CSCF.
❏ The Domain Name System is used to route the SIP messages.
(contd...)

Serving Call State Control Function
❏ The SIP registrar of the IMS subscribers is S-CSCF as it acts as the end point for IMS
authentication in the IMS network.
❏ It also coordinates the type of IMS services and the order in which the given IMS
subscriber uses those services.
❏ The authentication is performed by the S-CSCF and HSS can be informed about
the registration status of the IMS subscriber.
❏ To provide actual services for the IMS subscriber required Application Servers (AS)
in the SIP session is involved in the S-CSCF on the basis of the retrieved user
profile from HSS during registration.
(contd...)

Serving Call State Control Function
❏ It has built-in application server functionalities in some cases so that
higher flexibility can be achieved for routing the SIP sessions and
manipulating SIP headers in the SIP messages.
❏ Within the IMS architecture, the S-CSCF represents an important building
block in the case of voice, video and SMS over LTE.
(contd...)

E-CSCF/LRF
❏ The functionality required to complete an emergency IMS session is
called the Emergency Call State Control Function.
❏ After detecting that the nature of the session is an emergency, the
P-CSCF invokes the E-CSCF on the basis of the the received Request URI
parameter value.
❏ Afterwards, the required location information will be resolved by the
E-CSCF with the help of the Location Retrieval Function (LRF).
(contd...)

E-CSCF/LRF
❏ The received signaling level information is used by LRF from the terminal.
❏ In order to select the Public Safety Answering Point (PSAP), location data
is used so that emergency calls can be done from a given location.
❏ LRF converts the location to the PSAP address which is returned to
E-CSCF so that the call can be routed via MGCF to circuit-switched
networks.
(contd...)

Home Subscriber Server and Subscriber Locator Function
❏ HSS is the main subscriber data repository.
❏ The information related to identities and services of the given subscriber is
contained in this data.
❏ If there are multiple HSS entities in the IMS network, SLF is required so
that the requesting function has the knowledge of the individual IMS user
profiles’ location in the HSS entity.
(contd...)

Application Servers
❏ The work horses of the IMS architecture are AS by which critical business
services are provided for the IMS subscribers.
❏ The Telephony Application Server (TAS) is one of the most important
functionalities of 3GPP standard from the voice and video telephony point
of view.
❏ The IMS session path involves the Service Centralization and Continuity
Application Server (SCC AS) that supports the continuity of the service.
(contd...)

Application Servers
❏ SCC AS performs the session anchoring to transfer domain by using Single
Radio Voice Call Continuity (SRVCC) as well as Terminating Access
Domain Selection (T-ADS) is performed for selecting either a
circuit-switched or an IP-based access network so that call can be
terminated
(contd...)

MGCF, IMS-MGW, I-BCF and TrGW
❏ The routing of the SIP session between the IMS subscriber and the
circuit-switched endpoint is provided by Media Gateway Control Function
(MGCF) and the IMS-Media Gateway (IMS-MGW).
❏ The signaling-related tasks are performed by the MGCF such as SIP to SDP
signaling conversion.
❏ The user plane resources are controlled by MGCF.
❏ It is located in IMS-MGW.
❏ A single MGCF controls multiple IMS-MGWs and vice versa thus increases
flexibility of the network. (contd...)

MGCF, IMS-MGW, I-BCF and TrGW
❏ The transport-level interworking is handled by the IMS-MGW.
❏ The security functionalities are provided by using I-BCF and TrGW so that
Denial of Service (DoS) attacks from the unsecured IP interconnections
can be prevented but the functionalities related to user plane are also
performed.
(contd...)

Media Resource Function Controller and Processor
❏ The functionalities related to media plane are provided by MRFC and
MRFP.
❏ In this, in-band tones and announcements are injected as well as in-band
information is collected.
❏ Moreover, the support for network-based conferencing is also provided
by these functions.
(contd...)

SRVCC and ICS Enhanced MSC Server
❏ When the terminal moves from LTE to the circuit-switched network, the
continuation of the voice call is provided by the Single Radio Voice Call
Continuity (SRVCC).
❏ A normal Inter-MSC relocation will be performed by the SRVCC-enhanced
MSC Server if another MSC server controls the target radio access.
❏ The call will be established by the SRVCC-enhanced MSC Server to the
address specified by MME on the behalf of the terminal after committing
the target circuit-switched radio access resources.
(contd...)

4G LTE-A Radio Network

Introduction
❏ The frequency division multiplexing technique is used to define the radio
interface of the LTE.
❏ OFDMA (Orthogonal Frequency Division Multiplex) is used in the downlink
and SC-FDMA (Single Carrier Frequency Division Multiple Access) is used
in the uplink direction.
❏ A good protection is provided by the OFDMA against the fast varying radio
conditions.
(contd...)

Introduction
❏ The challenges are faced by the circuit design of user equipment because
of the peak-to-average power ratio (PAPR) behavior due to which
SC-FDMA is used in the uplink as these issues are handled by the terminal
in the better way.
❏ Both FDD (Frequency Division Duplex) and TDD (Time Division Duplex)
modes are supported by the LTE.
❏ Separate frequency bands are used for the uplink and downlink
transmission in the FDD mode.
(contd...)

Introduction
❏ Whereas in TDD timeslots of the same frequency band are used for both
downlink and uplink transmission.
❏ LTE provides the maximum data rates of upto 300 Mbps in downlink and
75 Mbps in uplink depending upon the bandwidth, MIMO variants and
modulation schemes.
❏ LTE-A provides data rates of over 1 Gbps in downlink by using wider
MIMO variants and carrier aggregation of up to five bands.
(contd...)

LTE Spectrum
❏ There are various FDD and TDD frequency bands identified by 3GPP for
radio interface of LTE.
❏ The regional frequency regulation defines the availability of these bands.
❏ B.1 - B.31 are defined for FDD and B.33 - B.44 are defined for TDD.
❏ B.15 and B.16 are not used.
❏ LTE uses spectral efficiency, bandwidths are 1.4, 3, 5, 10, 15 and 20 MHz.
(contd...)

RF Band Support
❏ The capabilities of chipset, costs balancing and coverage achievement
are the parameters to which the mains issues in the RF band support of
the user equipment of the LTE is related.
❏ Also, multiple frequencies demand antenna tuning.
❏ The RF bands support can be designed on the basis of the requirements
of the targeted region.
❏ It is important to use carrier aggregation and the support of carrier
aggregation frequencies is ensured by the OEM.
(contd...)

RF Band Support
❏ An independent receiver is added to support all the CA combinations and
the MIMO antennas for inter-band CA.
❏ In order to support all the planned CA combinations and MIMO
configurations, the additional switches, filters and diplexers are required.
❏ An adequate modem and Digital Signal Processor (DSP) support is
required for the contiguous CA and an additional receiver and in-band
filtering is needed for the non-contiguous CA in case of intra-band CA.
(contd...)

RF Band Support
❏ There is an increase in the number of CA combinations with the new 3GPP
LTE releases.
❏ The devices become more complicated with introduction of uplink CA in
the 3GPP Release 12.
❏ The use of the passive antenna design has the minimal impact in the
LTE/LTE-A user equipment.
❏ The supported bands are covered by the passive antennas all the time.
(contd...)

RF Band Support
❏ There is no need for additional Specific Absorption Rate (SAR) testing
because the functionality of transmitter does not change with the same
transmitter using the DL CA mode or the single band mode.
(contd...)

General Principle of OFDM
❏ In DL, OFDM (Orthogonal
Frequency Division
Multi-Carrier) is used by the
LTE.
❏ The LTE requirements for the
spectrum flexibility are
complied due to OFDM.
❏ The spectrum flexibility is
shown in figure. (contd...)

❏ The modulation technique used for data transmission in LTE/LTE-A is
Orthogonal Frequency-Division Multiplexing (OFDM).
❏ The data streams are split into several orthogonal subcarriers and then
transmitted.
❏ This will increase the symbol period.
❏ Hence, a constant channel is generated over each given subcarrier and
equalization can be simplified at the receiver.
(contd...)

❏ The bandwidth flexibility is provided by OFDM and high peak data rates
can be achieved.
❏ There is a difference between OFDM and traditional FDM as:
❏ A large number of narrowband subcarriers are used to map the
information stream that increases the symbol period compared to
single carrier schemes.
❏ To reduce the Inter-Carrier Interference the subcarriers are
orthogonal to each other.
(contd...)

❏ For maintaining orthogonality between subcarriers and eliminating
Inter-Symbol Interference (ISI) and ICI a guard interval is appended at
the beginning of each OFDM symbol which is called Cyclic Prefix (CP).
(contd...)

OFDM Transceiver Chain
❏ A simplified block diagram of a
single-input single-output
(SISO) OFDM system is shown
in the figure.
❏ There is a mapping of the
modulated (QAM/PSK)
symbols onto the orthogonal
subcarriers on the transmitter
side. (contd...)

❏ An Inverse Discrete Fourier Transform (IDFT) operation is used to accomplish
this.
❏ An Inverse Fourier Transform (IFFT) is performed efficiently.
❏ After that insert the CP and perform a parallel-to-serial conversion and then
transmit over the air interface.
❏ The reverse operations are performed at the receiver.
❏ After receiving at the receiver, the CP is removed and then data has been
taken into frequency domain by using a Fast Fourier Transform (FFT)
operation. (contd...)

❏ Hence, there is a simplification of channel estimation and equalization.
❏ At the end, there has been the demodulation of the equalized data
symbols and received bit stream can be recovered.
(contd...)

Cyclic Prefix
❏ There is an addition of a guard period at the beginning of each OFDM
symbol so that the negative effects of the multipath channel can be
mitigated.
❏ The guard period is called cyclic prefix.
❏ All the components of the multipath arrive within this guard time when
there is a longer duration of the guard interval as compared to the
maximum delay of the channel.
(contd...)

Cyclic Prefix
❏ CP will avoid the Inter-Symbol
Interference (ISI) as shown in
the figure.
❏ In case of CP, the last samples
of the OFDM symbol are
copied to the start of the
symbol.
❏ The cyclic prefix concept was
shown in the figure. (contd...)

Channel Estimation and Equalization
❏ The multipath channel corrupts the received symbols in the wireless
systems.
❏ The received signal will be equalized in order to recover the original
transmitted data by compensating the induced variations in the channel.
❏ A complex gain is experienced by each subcarrier symbol due to the
channel when the CP is longer than the maximum delay of the channel
and channel is slow fading channel.
(contd...)

❏ The channel in OFDM systems can be estimated by using different
approaches but the most suitable solution for the mobile radio channel is
pilot aided channel estimation.
❏ In this technique the pilot symbols which are the transmitting symbols are
known by both of the transmitter and receiver so that the channel can be
estimated at the receiver.
❏ The more the pilots, the more is the accuracy of estimation of channel but
the overheads will also increase and the data rate gets reduced.
(contd...)

Channel Estimation
and Equalization
❏ The idea of the LTE radio
resource block is shown in the
figure.
(contd...)

Channel Estimation
and Equalization
❏ Figure shows the cell-specific
reference signals mapping in
LTE with different numbers of
antenna ports and normal CP.
(contd...)

Channel Estimation
and Equalization
❏ Figure shows the two-port
MIMO in LTE where the cross
indicates the resource
elements that are not used in
the respective antenna port.
(contd...)

Channel Estimation
and Equalization
❏ Figure shows the four port
antenna set-up.
(contd...)

Channel Estimation
and Equalization
❏ Figure shows dedicated and
advanced reference symbols
for two cell-specific RS
according to Release 9 and
Release 10.
(contd...)

Channel Estimation
and Equalization
❏ The concept of the virtual
antenna ports is shown in the
figure.
❏ In DL, 8 physical antennas are
used to configure the eNodeB
but up to four parallel spatial
multiplexing layers are
supported by the Release 8
UEs. (contd...)

❏ Hence, there is a mapping of four co-polarized physical antennas to the
3GPP virtual antenna port 0 and mapping of the other four is done to the
virtual antenna port 1 so that this limitation can be addressed.
❏ The same reference symbols will be transmitted by each of the physical
antenna ports of the virtual antenna ports 0 and 1 respectively.
(contd...)

Modulation
❏ QPSK, 16-QAM and 64-QAM modulation schemes are used by LTE.
❏ The pilot symbols are used to estimate the channel of OFDM.
❏ Each individual OFDM subcarrier has a channel type corresponds to the
flat fading.
❏ The largest coverage areas are provided by the QPSK modulation but per
bandwidth capacity will reduce.
❏ More capacity with smaller coverage is provided by the 64-QAM.
(contd...)

Coding
❏ Turbo coding or convolutional coding is used by LTE.
❏ The OFDM signal is generated by using the Inverse Fast Fourier Transform
(IFFT).
❏ On the other hand, the original signal is combined by using the FFT at the
receiver.
(contd...)

Signal Processing Chain
❏ A serial-to-parallel conversion is used to form the OFDM signal after
coding and modulating the user data.
❏ The necessary number of parallel subcarriers are taken by the subcarrier
mapping from the other users before bringing the parallel subcarriers of
the user data.
❏ The CP is added to the start of the symbols so that the signal can be
protected against multi-path propagated components.
(contd...)

SC-FDM and SC-FDMA
❏ Single-carrier frequency-division multiplexing (SC-FDM) is a modulation
technique used in LTE for UL transmission.
❏ It is used for multipath mitigation and low-complexity equalization.
❏ The data symbols are spread over all the subcarriers carrying information
and a virtual single-carrier structure can be produced.
(contd...)

SC-FDM and SC-FDMA
❏ The principle of the SC-FDMA
transmission is shown in the
figure.
❏ The peak-to-average-power
ratio (PAPR) is lower in
SC-FDM as compared to
OFDM.
❏ Hence, transmitted power
efficiency of UE improved by (contd...)

SC-FDM and SC-FDMA
❏ The block diagram of a SISO
SC-FDM system is shown in
this figure.
(contd...)

CSI
❏ The information about the state of DL channel to eNodeB is delivered by
the UE Channel state information (CSI) feedback.
❏ It helps the eNodeB to decide the scheduling.
❏ the CSI has been measured by the LTE-UE during the call and PUCCH or
PUSCH channels is used to send it to eNodeB.
(contd...)

CQI
❏ The Channel Quality Indicator (CQI) is the important parameter of the
channel feedback.
❏ It has 16 levels from 0-15.
❏ The modulation and coding scheme (MCS) is indicated by the CQI value.
❏ LTE-UE reports the highest CQI index for the eNodeB during the LTE data
call.
❏ The value of CQI varies along the TTI interval.
(contd...)

RI
❏ When the LTE-UE is operating in MIMO modes along with spatial
multiplexing, the Rank Indicator (RI) acts as a reporting method.
❏ It is not used for single antenna operation or Tx diversity.
❏ It recommends the number of layers used in spatial multiplexing in the
LTE-UE.
(contd...)

PMI
❏ A set of information regarding the Precoding Matrix is given by the
Precoding Matrix Indicator (PMI).
❏ PMI is relevant in RI only with the MIMO operation.
❏ A closed loop MIMO is formed by the MIMO operation in combination with
PMI feedback.
(contd...)

4G LTE-A Terminals and
Applications

Introduction
❏ The business of LTE/LTE-A is growing fast and with increase in number of
devices, it starts acting as a base for modern communications.
❏ The increase in the use of sensors, power at lower cost and the third party
multiplexing are the general trends for the LTE/LTE-A devices.
❏ The optimization of integrating 4G into existing devices is one of the
biggest challenge for the manufacturers of the LTE device.
❏ To take full advantage of the advanced network, new and more capable
mobile devices are required by the users.
(contd...)

Introduction
❏ The new opportunities are provided by the fragmentation of the
LTE/LTE-A frequency bands globally but all the bands are not supported
by the devices.
❏ VoLTE (Voice over LTE) will be supported by the LTE/LTE-A devices.
(contd...)

Device Blocks and Functionality
❏ Any device category can be represented by the LTE/LTE-A user
equipment (UE) from USB dongle to highly advanced smart devices.
❏ The terminal of LTE/LTE-A may be any other connected or stand-alone
data device.
❏ An integrated IMS functionality is used to manage the voice calls of the
special devices in the same way as the VoIP calls are executed.
(contd...)

The ue-Category in Release 10 for DL

The ue-Category in Release 10 for UL

HW Architecture
❏ The functional blocks of the
LTE/LTE-A UE take care of the
transmission and reception of
signaling and data.
❏ OFDM is used to process the
bit stream in the reception of
the LTE-UE for single user
case as shown in the figure.
(contd...)

HW Architecture
❏ The user data is fed to the serial/parallel conversion for the multi-user
case and before performing the N-point IFFT, the subcarrier mapping is
done.
❏ The stream of each user is handled separately by taking each users data
flow to the equalization and sub-carrier de-mapping from the N-point FFT.
❏ Before the OFDM signal processing of the LTE/LTE-A UE, the modulation
and coding of the user data are executed.
(contd...)

HW Architecture
❏ One TTI (Transmission Time Interval) frame is the minimum interval of the
scheme modification that corresponds to 1 ms time.
❏ A set of modulation schemes is used to select the modulation scheme i.e.
QPSK (Quadrature Phase Shift Keying), 16-QAM (Quadrature Amplitude
Modulation with 16 decision points) and 64-QAM (Quadrature Amplitude
Modulation with 64 decision points).
❏ In the uplink direction, SC-FDMA is used for the transmission of the
LTE-UE.
(contd...)

Antenna Design
❏ During the pre-evaluation process, the antennas are needed to be
adjusted.
❏ The number of RF bands supported by the device is one of the biggest
challenges of LTE/LTE-A devices antenna design.
❏ The support for the next level of MIMO antenna is also the challenge for
the LTE-A devices.
(contd...)

Antenna Design
❏ Figure shows the placement of
the antenna in the user
equipment of LTE-A.
(contd...)

Batteries
❏ For the evaluation of the quality of the mobile devices, the performance of
the battery should be improved.
❏ The operators are developing the techniques so that demanding
requirements for the battery duration can be attained.
❏ To reflect realistic uses of devices, the mobile device are required to
handle practical use cases i.e. certain percentages for voice calls, short
messages, location-based services, and data transmission in the uplink
and the downlink shared between different radio access technologies.
(contd...)

Chargers
❏ The USB (Universal Serial Bus) connectors are used for the chargers of the
mobile devices.
❏ This will provide universal connectivity of the chargers and different
devices that have USB port support.
❏ The support for different current levels is the limitation for the
interoperability of the chargers.
❏ Some devices use non-standardized functionality for showing the
incompatibility issues which is another limitation of the USB chargers.
(contd...)

Power Amplifiers
❏ The power amplifier (PA) is the basis for all RF communications.
❏ The sufficient attenuation is provided to spurious emissions caused by the
harmonics of the transmitting signal over the spectrum in order to protect
the adequate power levels allowed by the 3GPP standards.
(contd...)

Envelope Tracking
❏ One of the optimization method is Envelope Tracking (ET) which is used
by PA in which the output power is based on the input voltage level.
❏ The use of maximum power constantly is the simplest solution.
❏ The most accurate solution is ET as there is least power overhead when
using this method.
(contd...)

4G LTE-A Functionality

States and Signaling Flows
❏ EPS and LTE UE has two states
i.e. EMM (EPS Mobility
Management) and ECM (EPS
Connection Management).
❏ The transitions between the
states and their overlapping is
(contd...)

❏ The LTE/SAE network has non achievable UE in the EMM-Deregistered state.
❏ The Attach procedure or the Tracking Area Update from GERAN or UTRAN is
used for the transition from the EMM Deregistered state to the
EMM-Registered state.
❏ The UE moves to the ECM-Connected state at the same time.
❏ The UE moves to ECM-Idle state after the release of the signaling.
❏ When the signaling connection has been established, the UE can move back
to ECM-Connected/EMM-Registered stage.
(contd...)

❏ If the Detach procedure is
implemented, the UE can also
move directly to the
EMM-Deregistered state.
❏ In the EMM-Deregistered
state, the UE is non attainable.
❏ The idea of the state transition
is shown in the figure.
(contd...)

Mobility Management
❏ In order to keep the track of the location of the UE, mobility management
is required.
❏ Paging and Tracking Area Update (TAU) are the procedures of the Mobility
Management.
❏ The requisite means are provided by the Paging procedure to send the
initial paging message in the Tracking Area (TA) level.
❏ When UE entered into a new Tracking Area, the Tracking Area Update has
been performed.
(contd...)

Mobility Management
❏ In the LTE Attach Procedure, there is the transition from the
EMM-Deregistered state to the EMM-Registered state.
❏ The UE can be paged in the EMM-Registered state so that it can be
reachable by the network.
(contd...)

Handover
❏ The Handover procedure in the LTE/SAE takes place in the same network
between the eNodeBs.
❏ It can also take place between different 3GPP networks.
❏ The handover performance requirements are defined by the 3GPP for
interruption delay of the handover procedure from the initiation to the
termination.
❏ The average interruption can be a maximum of 54 ms in DL and 58 ms in
UL in case of the inter-eNodeB handover for the user plane.
(contd...)

Handover
❏ For signalling plane, the average interruption time can be maximum of 58
ms.
❏ The maximum delays in the user plane can be up to 150 ms and 300 ms in
DL and UL, respectively for handover between the LTE/SAE and UTRA.
❏ Forward handover concept has been included in which the new radio path
is used to exchange the handover information between the UE and the
eNB.
(contd...)

Connection Management
❏ EPS Connection Management (ECM) has two states i.e. ECM-Idle and
ECM-Connected.
❏ The signaling connectivity has been described by them between the UE and
EPC.
❏ The connection management procedures can be any of the following:
❏ random access procedure;
❏ the LTE attach procedure;
❏ the User data connection set-up procedure;
❏ the connection release procedure. (contd...)

Random Access Procedure
❏ This procedure takes place when the UE starts making connection with
the network.
❏ There are two types of random access procedure defined by LTE/LTE-A
i.e. contention-based and non-contention-based random access
procedure.
❏ Both of these procedures are shown in the figures below.
(contd...)

Random Access Procedure

The LTE Attach Procedure
❏ RRC signaling link is used to make the LTE attach procedure by UE by
sending an LTE attach request message to the eNodeB.
❏ In this case, the EMM-Deregistered state is changed to EMM Registered
state.
❏ The signaling between MME and HSS is used to register UE in the SAE
network as shown in the figure.
(contd...)

The LTE Attach Procedure

The User Data Connection Procedure

The Connection Release Procedure

SMS over SGs
❏ The Short Message was delivered in the same way over LTE via signaling
as in earlier mobile networks.
❏ The Short Message is transferred transparently within the Non-Access
Stratum (NAS) protocol in the LTE-Uu interface between the terminal and
eNb.
❏ Any specific functionality is not required to support the SMS over SGs
from the eNodeB.
(contd...)

Combined EPS/IMSI Attachment

Mobile Originated Short Message

Mobile Terminated Short Message

Mobile Originated Call

Mobile Terminated Call

Mobile Terminated Call with MTRR

The Tracking Area
❏ The optimal initiation of the LTE connections is done by the Tracking Area.
❏ When the UE is in the ECM-Idle state and starts the communication, the
tracking area concept takes place.
❏ The network can send the initial signaling for the UE to a certain location
of the UE.
(contd...)

The Tracking Area
❏ The principle of the tracking
area is shown in the figure.
(contd...)

The Tracking Area

Paging Procedure

Carrier Aggregation

Introduction
❏ The high peak data rates and average throughput per cell are supported
by the LTE-A system with the wider bandwidths.
❏ LTE-A uses carrier aggregation (CA) with two or more component carriers
(CCs) so that bandwidths larger than 20 MHz can be supported.
❏ The multiple component carriers are used to transmit or receive data
when required bandwidth capability is beyond 20 MHz.
❏ The transmission bandwidth of upto 100 MHz can be allowed by
aggregating upto five component carriers.
(contd...)

CA Types and Scenarios
❏ The carrier aggregation also facilitates efficient use of fragmented
spectrum along with providing the peak data rate.
❏ Any of the channel bandwidths of 1.4, 3, 5, 10, 15, and 20 MHz can be taken
by each component carrier in LTE-A carrier aggregation.
❏ In LTE-A there are three CA types depending on the usage of the
spectrum i.e. intraband contiguous CA, intraband noncontiguous CA, and
interband CA.
(contd...)

❏ All the types are shown in the
given figure.
❏ In case of intraband contiguous
CA, a multiple of 300 kHz is used
as the spacing between center
frequencies of contiguously
aggregated CCs so that it will be
compatible with the 100-kHz
frequency raster.
(contd...)

❏ The operators with scattered spectrum within a given band uses intraband
noncontiguous CA.
❏ The spectral diversity gain is the main advantage of the noncontiguous CA
in which different frequencies have different types of fading channels.
❏ In case of contiguous CA, many subcarriers are used as guard bands and
hence spectrum can be saved by employing them for data and control
signal transmission.
(contd...)

❏ There is an aggregation of up
to 5 downlink (DL) CCs and 5
uplink (UL) CCs in LTE-A for
intraband as well as interband
CA.
❏ A different number of CCs can
be aggregated to the UE
connected to same eNB.
(contd...)

❏ The number of aggregated carriers are different in UL and DL in case of
FDD but in LTE-A the number of DL CCs is always more than the number
of UL CCs.
❏ The number of CCs will be same in TDD, each having same bandwidth
also.
❏ In all aggregated CCs, the frame structure used is also same.
❏ In LTE-A, there are five different scenarios for CA in which two different
CC frequencies F1 and F2 are considered in a cell such that F2 > F1.
(contd...)

Backward compatible carrier
❏ In all existing LTE releases, the
UEs can access a backward
compatible carrier.
❏ The UEs of LTE-A and LTE Rel
8 can share their spectrum.
❏ It acts as a single carrier or as a
part of CA.
(contd...)

Non-Backward
compatible carrier
❏ UEs of earlier LTE releases
cannot access a
non-backward-compatible
carrier.
❏ If the non-backward
compatibility originates from
the duplex distance, it acts as
single carrier or else as CA.
(contd...)

Non-Backward compatible carrier
❏ LTE-A UE operates more efficiently with non-backward-compatible CCs.
❏ The first OFDM symbol is used to transmit the physical DL shared channel
(PDSCH) in order to improve DL data throughput.
(contd...)

Carrier Segments
❏ The bandwidth extensions of the CCs compatible with Rel 8 are known as
carrier segments.
❏ In this mechanism, frequency resources are utilized to employ new
transmission bandwidths in a backward-compatibility.
❏ In this, PDCCH transmission can be reduced.
❏ The additional resource blocks are aggregated to CC by maintaining the
backward compatibility of the original bandwidth.
❏ They are adjacent and linked to one carrier which are not stand-alone.
(contd...)

Carrier Segments
❏ The synchronization signals, system information, or paging are not
provided by them.
❏ These are not used for random access or UE camping.
❏ The same hybrid automatic repeat request (HARQ) process, PDCCH
indication, and transmission mode can be supported by them as that by
the linked CC.
(contd...)

Carrier Segments
❏ Figure shows the notion of
carrier segment.
(contd...)

Extension Carrier
❏ A carrier that is not operated as a
single carrier is known as
extension carrier.
❏ It is a part of set of CC out of which
atleast one is a
stand-alone-capable carrier.
❏ A separate HARQ process, PDCCH
indication, and transmission mode
is supported by it as shown in
figure. (contd...)

PCell and SCell
❏ Each aggregated CC in LTE-A acts as a separate cell having its own cell
ID.
❏ CA configured UE can be connected to one primary serving cell (PCell)
and up to four secondary serving cells (SCells).
❏ The CCs corresponding to the PCell are the DL and UL PCCs.
❏ The CCs corresponding to the SCell are the DL and UL SCCs.
❏ PCell provides CA configured UE with only one RRC connection with the
network.
(contd...)

PCell and SCell
❏ The non-access stratum (NAS) mobility information can be provided by
the PCell at RRC connection establishment/reestablishment/handover.
❏ In one eNB, different PCell are provided to each UE.
❏ Handover procedure will change the PCell.
❏ Unlike SCell, there is not any deactivation and cross-scheduling of a PCell.
❏ Monitoring of PCell helps to trigger radio link failure (RLF).
❏ The UE will fall back to non-CA mode upon RLF.
(contd...)

PCell and SCell
❏ Once an RRC connection is established, the SCells has been configured
and additional radio resources may be provided by using them.
❏ A DL and optional UL resources are consisted in the SCell.
❏ A set of serving cells is formed when SCells are configured to combine
with PCell depending on the capabilities of the UE.
(contd...)

Collaborative Multipoint

General Description
❏ There wa a use of single point before LTE-A evolution i.e. UE received
signal from its serving cell that created interference for UE in adjacent
cells.
❏ The multiple baseband, radio frequency (RF), and antenna systems are
consisted in a single point in which one sector is served by each system.
❏ Hence, this will limit the intersector coordination but intrasite functions
quite good.
❏ The DL peak throughput and total sector throughput of LTE-A is higher.
(contd...)

General Description
❏ In multipoint, antennas that are not in close proximity are used for
transmission or reception.
❏ Multipoint differs from single-point as the separation between antennas is
the larger-than-normal.
❏ A set of UE is served collectively by several participating points in the
multipoint operation and are connected to single-point for coordination.
❏ There can be a switching of UE from single-point to multipoint operation
and vice-versa.
(contd...)

General Description
❏ The CoMP scheme is shown in
the figure.
❏ Multiple network nodes are
required for transmission/
reception that cooperate with
distributed or centralized
structures in order to act as
LTE-A in the case of CoMP.
(contd...)

General Description
❏ The multiple cells are involved in the CoMP to cooperate transmission to a
single UE so that the coverage can be improved and data rates and cell
edge and system throughput will be increased.
(contd...)

Introduction
❏ 3GPP defined that there is a dynamic coordination in DL CoMP transmission among
multiple separated transmission points.
❏ The coordination takes place everywhere within the cell or at the cell edge only
with respect to coordination position.
❏ There are two types of CoMP with respect to coordination nodes i.e. intra-eNB
CoMP and inter-eNB CoMP.
❏ There are several schemes that have been proposed for CoMP with respect to
coordination level such as coordinated scheduling (CS)/ coordinated beamforming
(CBF), dynamic cell selection (DCS), and joint processing (JP).
(contd...)

Introduction
❏ Cooperation occurs only in sectors of different sites in case of an
inter-eNB CoMP cooperating set.
❏ The interference problem at the cell edge can be addressed by this.
❏ A high-speed, low-latency, site-to-site backbone connection is required
for the cooperation.
❏ CoMP cooperating sets are provided with the static and dynamic
clustering.
(contd...)

Introduction
❏ The cooperation takes place only in the sectors of the same BS in one
site in case of an intra-eNB CoMP cooperating set.
❏ A high-speed, low-latency, site-to-site backbone connection is not
required in the cooperation.
❏ The size of the CoMP cooperating set and the number of sectors will be
same.
❏ Each transmission point has data for the cells which are controlled by
intra-eNB.
(contd...)

Introduction
❏ Figure shows the coordinated
scheduling for intercell CoMP
and intracell CoMP.
❏ There are two types of CoMP
on the basis of the type of
coordinated users i.e.
single-user MIMO (SU-MIMO)
and multiuser MIMO
(MU-MIMO). (contd...)

Introduction
❏ The figure shows that the
coordination will be CS/CBF,
DCS, and JP on the basis of
level of coordination.
❏ The coordinated transmission
is provided by Joint processing
from multiple cells to cancel
the active interference.
(contd...)

Introduction
❏ Cooperative MIMO (Co-MIMO) is another name for JP.
❏ In CS/CBF, data is available at the serving cell only but interference
coordination is used among surrounding cells in the CoMP cooperating
set to make user scheduling and beamforming decisions.
❏ Within a CoMP cooperating set, user-plane transmission is involved in
dynamic cell selection (JP/DSC)from one point at one time.
(contd...)

CoMP Cooperating Set
❏ It is a set of points separated geographically that are participating directly
or indirectly in transmission of PDSCH to UE.
❏ The CoMP cooperating set includes CoMP transmission points.
❏ The CoMP cooperating set contains the CoMP transmission points for JT.
❏ Every subframe has a single transmission point for DCS that can change
dynamically in the CoMP cooperating set.
❏ The serving cell is represented by the CoMP transmission point for
CS/CBF.
(contd...)

396458128-LTE-Advanced.pdf

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