IJ-V02-1516-E110(16-21)

International Journal of Exploring Emerging Trends in Engineering (IJEETE)

Vol. 02, Issue 02, MARCH-APRIL, 2015 WWW.IJEETE.COM

ISSN 2394-0573 All Rights Reserved 2014 IJEETE Page 16

LTE AND WIMAX FUTURE TECHNOLOGY: A COMPREHENSIVE

SURVEY

Gagandeep Kaur Virk1, Gaganpreet Kaur

2

1,2(Assistant Professor, Department of Computer Science,

MMEC, Maharishi Markandeshwar University, Ambala, India)

Abstract Increasing demands for higher bandwidths and in turn high data rates lead to the

development of fourth generation technologies.

Long - Term Evolution (LTE) and Worldwide

Interoperability for Microwave Access (WiMAX)

are the basis for evolving from third generation

(3G) to fourth generation (4G) telecommunication

services. This paper provides an overview of next

generation telecommunication networks- LTE and

WiMAX. They are compared to each other and

with current telecommunication networks. It also

shows their availability in the world and explains

which of these two networks is superior in which

case and gives an outlook about their successors -

LTE-Advanced and WiMAX release 2.0.

Keywords LTE; 3G; 4G; WiMAX; LTE- Advanced.

I. INTRODUCTION

From recent few years telecommunication authorities are busy deciding how to emerge to 4G environment motivated by the exponential increase in the demand for advanced telecommunication services which require wider spectrum and higher quality of services. The telecommunication industry experts on the other hand are trying hard to standardize new mobile wireless systems that can cope with the desire and ambitions of telecommunication users and pave the way for evolving new technologies known as WiMAX and LTE.

Long - Term Evolution (LTE) is the global standard for the fourth generation (4G) telecommunication services, which is based on GSM/EDGE and UMTS/HSPA network technologies.LTE uses carrier bandwidths, from 1.4 MHz up to 20 MHz and the bandwidth to be used by a particular device depends on the

frequency band and width of spectrum available to the network operator. It provides higher data rates of 300Mbps peak on the downlink and 75 Mbps peak on the uplink and supports both Frequency Division Duplex (FDD) and Time Division Duplex (TDD).

LTE Advanced evolved from LTE and was standardized in March 2011. LTE was enhanced to LTE Advanced to meet the technical requirements of ITU-R that were specified in its IMT-Advanced specification because those requirements were not supported by LTE. So, LTE Advanced is called as True 4G by ITU. World Radio Communication Conference proclaimed recently that LTE-A will practice the accessible spectrum for channels above 20 MHZ geographically. In addition to that it must be taken care for those areas of the geography in which channels are not obtainable. There are numerous recompenses of LTE that comprises:

Topology network

Heterogeneous network with squat power nodes

New relay nodes

Advancement in low power nodes

Improvement in capacity and coverage

Introduce multicarrier that can set to 100 MHz spectrum.

On the other hand, Worldwide Interoperability for Microwave Access (WiMAX) is a wireless communication standard which may provide high speed data transfer of 30 to 40 megabitper-second [3] developed in April 2001 under the specifications of IEEE 802.16 standard. The architecture of this network also involves the physical and data transfer layer through which the data is configured. WiMAX was designed as an alternative to Cable and Digital Subscriber Line




(DSL) to provide broadband internet access. The WiMAX network is also compatible with 802.11 network topology. The first IEEE 802.16 is now termed as Fixed WiMAX and later on it got adopted by other organizations like Wi Fi Alliance, Wi Bro in Korea [6]. As the time passed on, revisions in the WiMAX technology has always been presented by different organizations.

The WiMAX is a solid replacement for the mobile users. It is sometimes referred to as "Wi-Fi on steroids" [7]. Previous mobile users were configured with GSM and CDMA like technology which is getting replaced rapidly with the technology like WiMAX & LTE. It is similar to Wi-Fi, but it can enable usage at much greater distances [8]. Consequently the use of wireless microwave backhaul is on the rise in North America and existing microwave backhaul links in all regions are being upgraded [9]. Capacities of between 34 Mbit/s and 1 Gbit/s [10] are routinely being deployed with latencies in the order of 1 ms.

The two technologies, WiMAX and LTE, competed with each other starting from their pre-4G versions and continued with their 4G versions while having much in common. It looks like that finally WiMAX gave up the competition and selected to harmonize and integrate with LTE in its future harmonized WiMAX advanced standard supporting multiple access technologies. This work addresses the technical similarities and differences between the two technologies trying to pinpoint those differences that advantage one technology over the other. Other factors like commercial, historical, political, etc. which might advantage one technology over the other technology are also exploited.

The rest of the paper is organized as follows: Section II presents the comparative components of both LTE and WiMAX. Section III discusses some of the main technical differences between the two technologies, while Section IV discusses the security factors that favor one or the other technology and finally Section V discusses the future of both technologies followed by the conclusions in Section VI.

II. COMPARARTIVE COMPONENTS OF

LTE AND WIMAX

A. LTE

LTE system entails of Radio Link Control (RLC), MAC, PHY, Radio Resource Control (RRC) and Transceiver. These are associated with logical, transport, physical channels. Physical layer transport channels compromise communication to MAC or higher channels. LTE logical channels are offered by MAC.

Figure.1 LTE: Layer Architecture

The system model can be described as:

LTE networks with heterogeneous QoS services are addressed here. Constant Bit Rate (CBR) and Best Effort (BE) has been taken into consideration. The sets of cells, total users, CBR users and BE users are considered N, K, C and B respectively. It can be easily seen that

K = C B (1)

An assignment indicator can be denoted as I t, k (t) which is equal to 1 when K is served in time t and 0 otherwise. Time t can be used as load balancing time, which is the time span between 1 and t+1, and is of size 1 ms.

The system model can be described by showing mapping between load and throughput, this can be represented as:

R (S I N Ru) = log2 ( 1 + S I N Ru)

Where SIN Ru is Signal to Noise Ratio and amount of bandwidth required will be:

Nu = Du / (R (S I N Ru). BW) (2)




Where Nu is the addictive Gaussian noise. Since load balancing is periodically done on large scale, we use E (S I N R (t)) to represent expectation of SINRu between time ( t-1, t), thus average bandwidth can be recognized as:

E I, k (t) = log2 (1 + E [SIN R I,k (t) ]) [bps/hz]

For K users, resource allocation depends on the QoS parameters.

Figure.2 Network model with heterogeneous users

B. WIMAX

Components which are related to WiMAX are described below [11].

a) Subscriber Station

Subscriber Station is one who provides connectivity to WiMAX technology. They are also termed as SS. The SS can be used in the following item sets

1) Hand Sets (Much similar to the smart phones)

2) PC cards or USB dongles

3) MP3 players

b) Gateways

A gateway allows you to transfer the data from

one end to another. Service providers in India like

BSNL, Airtel, Idea, and Reliance are the major

vendors for such kind of services. WiMAX

gateway devices are available in both indoor and

outdoor versions from several manufacturers

including Vecima Networks, Alvarion, Airspan,

ZyXel, Huawei, and Motorola [12]. In addition to

this on international level HUAWEI [13],

MOTOROLA are one of the major vendors. These

vendors can configure the gateways for indoor as

well as outdoor. The vendor might configure the

following for the WiMAX access point.

1) ETHERNET PORT SYSTEM

2) WI-FI HUB

3) ANALOG TELEPHONE

4) SATELLITE DISH

c) External modems

A USB flash drive can also cat as a WiMAX

access point. USB devices mode opts this kind of

service for the internet access.USB can provide

connectivity to a WiMAX network through what is

called a dongle [14].

d) Mobile phones

HTC announced the first WiMAX enabled

mobile phone, the Max 4G, on November 12,

2008.WiMAX is a supplement to the IEEE

Standard 802.16-2004 [15]. There were around 1.7

million pre-WiMAX and WiMAX customers in

Asia - 29% of the overall market - compared to 1.4

million in the USA and Canada [16].

e) Triple Play

WiMAX supports technologies that offer triple

play services. On May 7, 2008 in the United

States, Sprint Nextel, Google, Intel, Comcast,

Bright House, and Time Warner announced a

pooling of an average of 120 MHz of spectrum

and merged with Clearwire to market the service

[18].

f) IEEE 802.16 Standard

WiMAX uses IEEE 802.16 Standard.

SOFDMA (used in 802.16e-2005) and OFDM256

(802.16d) are not compatible thus equipments will

have to be replaced if an operator is to move to the

later standard (e.g., Fixed WiMAX to Mobile

WiMAX).

g) Integration with IP based network




WiMAX can be merged with IP based network,

as stated by ISP providers. There is a proposal

called WiMAX proposal forum that wants

connections between some layers:

ASN: Access Service Network

BS: Base station, part of the ASN

ASN-GW: ASN Gateway, part of the

ASN

CSN: Connectivity Service Network

HA: Home Agent, part of the CSN

AAA: Authentication, Authorization

and accounting Server, part of the CSN.

Figure.3 WiMAX Network Architecture

III. TECHNICAL DIFFERENCES BETWEEN LTE AND WIMAX

As can be deduced from the previous section, there are lots of technical similarities between the two technologies in architecture and targets. Both uses OFDMA [19] with flat-IP architecture and both are meant to meet or even surpass IMT-Advanced requirements with similar technologies. Nevertheless, a number of technical differences exist. Some of these differences with mobile WiMAX (WiMAX 1.0) compared to LTE and WiMAX 2.0 compared to LTE-Advanced are the following:

TABLE.I Technical Differences

S.No Feature Property

1 Duplex Mode Both LTE and WiMAX

provide for both TDD and

FDD. However, FDD was the

focus of all telecom companies

and continued throughout the

different generations. TD-LTE

is gaining popularity as

migration path of the

synchronous CDMA of China

3G. Wi- MAX, on the other

hand, had TDD focus

throughout.

2 Spectrum Legacy LTE and LTE

Advanced use Licensed IMT-

2000 bands like 700, 900,

1800, 2100, and 2600 MHz

while legacy WiMAX is

Licensed & unlicensed, at 2.3,

2.5, 3.5 and 5.8 GHz bands.

Thus LTE is generally

available at preferred low

frequency band which gives it

coverage advantage.

3 Inter-carrier

Spacing

LTE uses a standard 15 KHz

inter-carrier spacing while

WiMAX 2.0 uses 10.94 KHz.

The larger the inter-carrier

spacing, the higher the

immunity against Doppler

spread. LTE can handle

mobility speeds up to 350

km/hr while WiMAX can

support speeds of the order of

120 km/hr and WiMAX 2.0 up

to 350 km/hr.

4 Access

Technology

LTE Advanced access

technology for its downlink

(OFDMA) is different from its




uplink. In uplink, Single

Carrier FDMA (SC-FDMA) is

used. SC-FDMA reduces

Peak-to-Average-Power-Ratio

(PAPR) by 3 - 5 dB giving rise

to uplink improvements that

can be utilized to improve

coverage or throughputs of cell

edge users. 802.16m uses

SOFDMA for both uplink and

downlink. In fact, the major

problem in extending GSM

TDMA and wideband CDMA

to broadband systems is

increased receiver complexity

with multipath signal

reception.

5 Fast Fourier

Transform

(FFT) -Size

Large dF required against

Doppler => higher velocity in

LTE.

6 Mobility LTE is fully embedded in the

3GPP world incl. inter RAT

HO, but WiMAX has less

mobility.

IV. COMPARATIVE STUDY ON

SECURITY

In this section we will compare WiMAX and

LTE with each other on the basis of security

parameters. In an enterprise environment, the

security is very important, and the security

requirements contain two aspects: 1) the device

that will be connected to IT network must be

authenticated; 2) the users that want to use IT

service must be authenticated. To meet these two

main requirements, enterprise security credentials

like identity, certificates, username and password,

are required to be authenticated. To authenticate

these credentials, security infrastructures, such as

Active Directory (AD) server and CA services, are

usually deployed as IT services.

The WiMAX can use both EAP_TLS and EAP_TTLS protocol to do authentication. In

EAP_TTLS protocol, the enterprise security credentials can be integrated seamlessly.

The LTE have totally different security mechanisms, which is called AKA. In this authentication mechanism, only a provisioned and pre-shared key is authenticated. This is not enough secure in enterprise environment.

V. FUTURE OF LTE AND WIMAX

WiMAX had the precedence advantage over LTE in bringing to light much of the themes currently adopted such as the flat architecture, all IP network and TDD structure. 3GPP on the other hand, moved from all circuit switched of 2G, through half packetized of 2.5G and 3G and finally to all IP in LTE and LTE-Advanced. The objective of telecom companies from the start was big customer base, public networks and wide coverage while WiMAX headed to serve vertical segments requesting broadband. This, together with the previously discussed factors, made WiMAX people realize that the ecosystem of WiMAX as a stand-alone technology cannot continue to compete with 3GPP stream and attractive LTE. WiMAX forum had to set plans to proceed.

VI. CONCLUSION AND FUTURE SCOPE

In this paper, the comparison between LTE and WiMAX technologies has been presented. WiMAX and LTE have several similarities, but they differ in their evolution, industry support, and deployment models. It is interesting to see the role being played by these two technologies in 4G market, which aims to achieve mass deployment of broadband mobile services. This paper results in a conclusion that WiMAX and LTE can be used as the next generation of Mobile Enterprise Network.

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[17] Orthogonal frequency-division multiplexing

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AUTHORS BIBLIOGRAPHY

Gagandeep Kaur Virk received

her B.Tech degree in CSE from

BFCET, Bathinda, Punjab in 2012

and her M.Tech in CSE from Giani

Zail Singh PTU Campus, Bathinda,

Punjab in 2014. Currently she is

working as Assistant Professor in

MMEC, Mullana Ambala,

Haryana.

Gaganpreet Kaur received her

B.Tech degree in CSE From AIET,

Faridkot, Punjab in 2012 and her

M.Tech in Software System from

GNDU,Amritsar , Punjab in

2014.Currently she is working as

Assistant Professor in MMEC,

Mullana-Ambala, Haryana.

IJ-V02-1516-E110(16-21)

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