A comparative study of wimax and lte

A COMPARATIVE STUDY OF
WiMAX AND LTE
Seminar Presentation
By
Hanie Salim
B080021ec
B.Tech Electronics and Communication Engineering ,NIT Calicut

Importance
 Mobile device and mobile networks are more
popular
 More data required
 People want to access internet from anywhere
 Services like IPTV increase the need for high data
rates
 As demand increased, current telecommunication
networks reach their limits
 Solution-next generation networks like WiMAX and
LTE

2 Hanie Salim (B080021EC),NIT calicut 19/09/2011

An overview of current telecommunication networks

3 Hanie Salim (B080021EC),NIT calicutfrom
Figure taken www.dailywireless.org 19/09/2011

 Worldwide interoperability for microwave access
 IEEE 802.16d standard in 2004 – fixed wireless
internet service
 Enhanced version IEEE 802.16e in 2006- Mobile
wireless access
 Managed by WiMAX forum for interoperability of
different products
 Supports transfer rates up to 46 Mbps in DL and
4 Mbps in UL


 Supports scalable system bandwidth using time
division duplex(TDD)
 So it can use 3.5,5,7,8.75 and 10 MHz as BW
 Supports both TDD and FDD, prefers TDD
 Maximum coverage is 50 km for fixed usage and 5km
for mobile usage
 Support vehicular speed up to 120 kmph
 2 major releases-WiMAX release 1.0 and release 2.0


Features of WiMAX release 1.0
 Access service network(ASN) & Connectivity service
network (CSN) mobility for mobility support
 Paging & location management
 IPV4 & IPV6 connectivity
 Pre provisioned / static QoS
 Optional radio resource management(RRM)
 Network discovery/selection
 Roaming (RADIUS only)
 3gpp WLAN compatible internetworking

WiMAX release 1.5 features:
 Over the Air (OTA) activation & provisioning
 Location based services (LBS)
 Multicast broadcast services (MBS)
 IMS(IP multimedia subsystem) integration
 Dynamic QoS and policy and charging (PCC) compatible
with 3GPP Release 7
 Telephony VoIP with emergency call services and lawful
interception
 Full NAP sharing support
 Diameter-based authentication, authorization and
accounting (AAA)

QoS for WiMAX:

 Reservation based access
 Use frames, each frame -2
sub frames
 Duration 2 to 20 ms
 Flexible ratio for DL/UL

WiMAX frame

Hanie Salim (B080021EC),NIT calicut Figure source: www.ecee.colarado.edu
8 19/09/2011

 Use OFDMA in DL & UL
 OFDMA- multi-user ver. Of OFDM
 Advantages of OFDMA –high spectral efficiency,
efficient implementation using FFT & low sensitivity
to time synchronization errors
 scalable by flexibly adjusting FFT sizes & channel BW
with fixed symbol duration and subcarrier spacing
 Sensitive to frequency sensitive errors


 3 power saving classes- different on-off time
• Class 1 - window increase exponentially from
minimum value to maximum
• Class 2 - fixed sleep window length
• Class 3 – MS know when to expect next packet
 Security sub layer present under MAC layer
 Extensible Authentication Protocol (EAP)
 Privacy and Key Management protocol (PKM)
 Encapsulation protocol


 Use MIMO technology to increase transfer rate
 2 categories:
• Open loop MIMO- the transmitters do not need
explicit knowledge of the channels
• Closed loop MIMO- transmitter forms antenna
beams adaptively based on the channel side
information (Tx AA)
 Logical entities of NRM
• Access service network(ASN)
• Connectivity service network (CSN)


Network reference model for WiMAX
Figure source: www.eetimes.com

 Long term evolution-developed by 3GPP in 2008
 LTE standard is officially known as “document 3GPP
Release 8” Or 3.9G
 Supports peak data rates of 100 Mbps in DL & 50
Mbps in UL, using 20 MHz spectrum
 With MIMO it can reach up to 300Mbps
 Variable spectrum 1.25, 2.5, 5, 10, 15 and 20 MHz
 A cell radius 100 km with slight degradation after 30
km and reach over 200 users per cell (with 5 MHz
spectrum)


 Optimized for low speeds 0 - 15 km/h , supports
speeds up to 350 km/h.
 RTT below 10 ms possible.
 Use OFDMA in DL & SCFDMA in UL
 OFDMA - power inefficient, because of high peak-to-
average-power ratio (PAPR)
 Since DL start from BS no problem, But UL start from
MS ,hence SCFDMA (low PAPR)


Architecture:
 Two-node architecture - only two nodes are involved
between user equipment & core network.
 The base station (eNodeB) & the serving gateway (S-
GW) in the user plane and the mobility management
entity (MME) in the control plane.
 LTE architecture is composed of Core Network (CN)
and Access Network (AN), where CN corresponds to
the Evolved Packet Core (EPC) and AN refers to E-
UTRAN.
 The CN and AN together correspond to Evolved
Packet System (EPS)

LTE overall architecture

Figure source: www.wiki.hsc.com

 EPS connects user to Packet data network(PDN)
 Functions of MME- CN node signalling for mobility
between 3GPP access networks, S-GW selection,
roaming, authentication, bearer management functions
and NAS (Non Access Stratum) signalling
 S-GW terminates the interface towards E-UTRAN.
 For each user in EPS, at given time, a single S-GW is
responsible for transferring user IP packets, lawful
interception & mobility anchor for inter eNodeB
handover and for inter-3GPP mobility.


 Power-saving mechanisms: turn off the transmitter
when idle.
• It uses Discontinued Reception (DRX) & Discontinued
Transmission (DTX).
 Security mechanisms : similar to WiMAX
• use security keys between transmitter &receiver to
ensure a secure connection .
• LTE also offers a key derivation protocol, which resets
the connection if corrupt keys are detected.


QoS:
 Reservation based access
 Each frame is 10 ms long
 The 0th and the 5th sub
frames are always reserved for
DL
 Other frames can be DL, UL
or a switch point
 This switch point method
makes the transmission more
dynamic in allocating
resources
Figure source: IT pro 2010

4 x 4 MIMO configuration

Figure source: IT pro 2010


Comparison

 Released in 2005  Released in 2009
 46 Mbps in DL and up to  300 Mbps in Dl and 75
4 Mbps in UL Mbps in the UL
 Support BW 3.5 MHz to  Support bigger range of
10 MHz BW 1.4 MHz to 20 MHz
 Range up to 50 km,  Bigger range up to 100 km,
optimized for 1.5 to 5 km optimized for 30 km
 Support speed up to 120  Support speed up to 350
km/h km/h


Comparison

 Use OFDMA in both DL  Use SCFDMA in UL and
and UL OFDMA in DL
 Frame is separated into DL  From 10 sub-frames only 2
and UL sub-frame allocate are reserved for DL, more
resources to different users dynamic, so they reach
 Duplex mode only TDD is smaller delays.
commercially available  Both FDD & TDD
 Backward compatibility to  Inter radio technology
3G/2G not present handover possible

4G Requirements
 Both WiMAX & LTE do not meet all 4G requirements
 4G specifications, also known as IMT-Advanced:
 Max. data rates up to 100 Mbps for mobile access
 Max. data rates up to 1 Gbps for fixed access
 Flat all-IP architecture
 High mobility up to 500 km/h.
 scalable channel bandwidth
 Solution : LTE’s successor, LTE-Advanced and
WiMAX’ next release WiMAX 2.0.


 Long term evolution advanced, officially known as
3GPP Release 10
 Recognized as IMT A in October 2010
 Commercial availability expected from 2014
 Peak data rate of 1 Gbps in DL (low mobility) & up to
500Mbps in UL
 BW extended up to 100 MHz using channel
aggregation
 MIMO to be used in UL also
 Support 8x8 MIMO


WiMAX 2.0
 WiMAX release 2.0 recognized as IMT in October
2010
 IEEE 802.16m standardized in April 2011
 Backward compatibility with all 802.16 standards
 DL rate >300 Mbps, 4x4 @ 20MHZ
 UL rate >135 Mbps, 2x4 @ 20MHz
 Support channel BW of 5,10,20,40 MHz
 Mobility up to 350 km/h


Technical comparison of LTE and WiMAX

26
Figure
Hanie Salim (B080021EC),NIT calicut source: www.kuncoro.co.uk 19/09/2011

References
 [1] M.Chang, Z. Abichar, and Chau –Yun Hsu, “Wimax vs. lte:
Who will lead the broadband mobile internet?,” IT Professional, vol.
12, no. 3, pp. 26 - 32, 2010.
 [2] Ozgur Oyman , Jeffrey Foerster ,Yong-joo Tcha and Seong-
Choon Lee , “Toward Enhanced Mobile Video Services over
WiMAX and LTE,” IEEE Communications Magazine ,vol. 48,no.8,pp.
68 – 76,2010
 [3] J. Conti, “Lte vs wimax: the battle continues,” Engineering
Technology, 2010.
 [4] Leo Yi ,Kai Miao ,Adrian Liu,” A comparative study of WiMAX
and LTE as the next generation mobile enterprise network,”
Advanced Communication Technology(ICACT),pp. 654-658,feb 2011.


A comparative study of wimax and lte

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