4G Revolution: WiMAX Technology

Sarla More Professor and Head

Department of Computer science and Engineering Thakur Shivkumar Singh Memorial Engineering College

Burhanpur, India sarlamore@gmail.com

Dr. Durgesh Kumar Mishra Professor and Head

Department of Computer science and Engineering Sri Aurobindo Institute of Technology

Indore, India drdurgeshmishra@gmail.com

Abstract— The 4G Revolution has begun with many of the advantages in wireless technology. The IEEE802.16 standard worldwide interoperability for microwave access is a technique which is used basically for the wireless and broadband for allowing high speed internet access for long distances. This new technique has made everything an mobile activity whether it is used as in business purpose or any other kind of task. The higher capacity and reliability of WiMAX make it useful in an efficient way. Security is the major challenge in wireless technology as because in wireless system it’s very easy to tune with the radio signals. Security concerns in WiMAX with fixed and mobile stations. In fixed location WiMAX for internet access a fixed location radio technology is used rather than cable modem or DSL services. In mobile WiMAX a fixed location wireless access is provided to cable modem and DSL services. The comparative study between the fixed and mobile WiMAX in this research make some important issued to understand about this. The various generations of mobile technology are mentioned here to demonstrate the differences and the advantages of this new revolution. The very advance techniques of LTE and WiMAX are differentiated on various characteristics. And the security issues are there to resolve many of the problems that can harm to the wireless communication.

Keywords—: WiMAX, DSL, modem, LTE

I. INTRODUCTION

The IEEE802.16 standard worldwide interoperability for microwave access is a technique which is used basically for the wireless and broadband for allowing high speed internet access for long distances. Worldwide Interoperability for Microwave Access (WiMAX) will play an important role in the Fixed Broadband Wireless Access (FBWA) market since it is more cost-effective and faster to set up. WiMAX is a fixed Broadband Wireless Access system (BWA) based on the IEEE 802.16 standard. WiMAX is used for fixed and mobile accesses. Now a days for fixed stations it can access up to the speed of 40 Mbit/s and expected in future for 1Gbit/s. for the fixed stations WiMAX provide broadband wireless access up to 30miles or 50kilometers, and for the mobile stations it provides 3-10miles or 5 to 15 kilometers. The mobility feature of WiMAX technology offers to connect to devices such as laptops, PDAs for moving and still have the ability to connect with the network. Interfacing is an feature of WiMAX technology which makes possible to

connect on1 base station to multiple stations in few hours. Accessing the services of WiMAX technology is provided in an easy way.

II. ADVANCED FEATURES OF WIMAXAn important and very challenging function of the WiMAX system [3] [5] is the support of various advanced antenna techniques, which are essential to provide high spectral efficiency, capacity, system performance, and reliability:

A. Smart antenna Technology Smart antenna technologies typically involve complex vector or matrix operations on signals due to multiple antennas. OFDMA allows smart antenna operations to be performed on vector-flat sub-carriers. Complex equalizers are not required to compensate for frequency selective fading. OFDMA therefore, is very well-suited to support smart antenna technologies. In fact, MIMO-OFDM/OFDMA is envisioned as the corner-stone for next generation broadband communication systems. Mobile WiMAX supports a full range of smart antenna technologies to enhance system performance. The smart antenna technologies supported include:

Beam forming. With beam forming, the system uses multiple-antennas to transmit weighted signals to improve coverage and capacity of the system and reduce outage probability. Space-Time Code (STC). Transmit diversity such as Alamouti code is supported to provide spatial diversity and reduce fade margin. Spatial Multiplexing (SM). Spatial multiplexing is supported to take advantage of higher peak rates and increased throughput. With spatial multiplexing, multiple streams are transmitted over multiple antennas. If the receiver also has multiple antennas, it can separate the different streams to achieve higher throughput compared to single antenna systems. With 2x2 MIMO, SM increases the peak data rate two-fold by transmitting two data streams. In UL, each user has only one transmit antenna, two users can transmit collaboratively in the same slot as if two streams are spatially multiplexed from two antennas of the same user. This is called UL collaborative SMMaintaining the Integrity of the Specifications.

978-1-4673-2590-5/12/$31.00 ©2012 IEEE

B. Fractional frequency reuse WiMAX supports frequency reuse of one, i.e. all cells/sectors operate on the same frequency channel to maximize spectral efficiency. However, due to heavy co-channel interference (CCI) in frequency reuse one deployment, users at the cell edge may suffer degradation in connection quality. Users can operate on sub-channels, which only occupy a small fraction of the whole channel bandwidth; the cell edge interference problem can be easily addressed by appropriately configuring sub-channel usage without resorting to traditional frequency planning.

The flexible sub-channel reuse is facilitated by sub-channel segmentation and permutation zone. A segment is a subdivision of the available OFDMA sub-channels (one segment may include all sub-channels). One segment is used for deploying a single instance of MAC.

Permutation Zone is a number of contiguous OFDMA symbols in DL or UL that use the same permutation. The DL or UL sub-frame may contain more than one permutation zone.

C. Multicast and broadcast service(MBS) Multicast and Broadcast Service (MBS) supported by WiMAX satisfy the following requirements:

High data rate and coverage using a Single Frequency Network (SFN)

Flexible allocation of radio resources Low MS power consumption Support of data-casting in addition to audio and video streams Low channel switching time

The MBS service can be supported by either constructing a separate MBS zone in the DL frame along with unicast service (embedded MBS) or the whole frame can be dedicated to MBS (DL only) for standalone broadcast service.

III. ADVANTAGES OF 4G WIMAX 1. Good standard: Mobility, roaming and meshing supported by WiMAX as an IEEE standard. Long range: compared to other existing technologies WiMAX is able to provide an significant range. Low cost: reduced fixed broadband prices and the network expansion cost also reduced. Quality of service (QoS) support: the MAC protocol guarantees the service level and support QoS. Non-line-sight support: to become less susceptible to obstacles it operates on 2 to 11GHz. Providing portable mobile broadband connectivity: across cities and countries through a variety of devices. Providing a wireless alternative to cable: and digital subscriber line (DSL) for "last mile" broadband access. Providing data, telecommunications (VoIP) and IPTV services (triple play). Providing a source of Internet connectivity: as part of a business continuity plan.

IV. (A) COMPARISON OF FIXED AND MOBILE WIMAX Features Fixed WiMAX Mobile WiMAX

Network Architecture

Fixed, Nomadic, Portable

Fixed, nomadic, portable, mobile

PHY Technology

OFDM 256 OFDMA 128, 512, 1024, 2048

Duplexing Format

TDD, FDD, HD-FDD TDD, FDD, HD-FDD

Channel size 1.25-20 MHz 1.25-14 MHz Modulation 64QAM, 16QAM,

QPSK and BPSK 64QAM, 16QAM, QPSK and BPSK

Spectrum Profiles

2.5GHz, 3.5GHz and 5.8GHz

2.3GHz, 2.5GHz, other TBD

QoS Features Best effort, non real time polling service, real time polling service, unsolicited grant service

Same as fixed WiMAX plus Extended real-time polling service

(B ) COMPARISON OF VARIOUS GENERATION

V. WIMAX ARCHITECTURE One ISP server is there for providing the connectivity with IP based network [2]. The mobile station (MS), the access service network (ASN) and the connectivity service network (CSN) are the main functional modules for providing the various functions. Separating the functions we can have mobile management, establishment of tunnel and triggering, radio resources, dynamic host control, multicast group and Quality of service provided by the base station. ASN provides routing, radio resources management and key encryption functions. As the name suggests CSN handles connection of internet, the user services and all the other networks. Base station having the electronic devices and WiMAX Tower is responsible for broadcasting the WiMAX signals, the tower like GSM network broadcast radio signals up to 30 miles. For connecting to the WiMAX network some receiver is there which are stand alone antenna or for laptops or computers PCMCIA cards. Using the high speed microwave links one WiMAX base station is connected to many base stations and these microwave links are known as backhaul. With the help of this the WiMAX connection and roaming is maintained.

Generation Definition Throughput Technologies 1 Analog 14.4kbps (peak) AMPS, NMT 2 Digital

narrowband circuit data

9.6/14.4kbps TACS TDMA(IS-136) GSM, CDMA(IS-95)

2.5 Packet data 171.2kbps (peak) GPRS 3 Digital

broadband packet data

3.1mbps (peak) 500-700 kbps

CDMA (IXRITT, EV-D0,UMTS, EDGE, VIRRON, SPRINT, AT&T,T-BMOB)

3.5 72mbps Upto3.6/7.2/14.4mbps(peak) 1-3mbps

HSPA (High speed packet access)

4 Digital broadband packet, all IP very high throughput

100-300 mbps (peak) 3.5mbps,100+mbps (Wi-Fi)

WiMAX, LTE, Wi-Fi (Metro)

VI. COMPARATIVE STUDY ABOUT LTE AND WIMAX [4] [6]

VII. SECURITY The mobile WiMAX incorporates the most advanced security features that are currently used in wireless access systems. These include Extensible Authentication Protocol (EAP) based authentication, Advanced Encryption Standard (AES) based authenticated encryption, and Cipher-based Message Authentication Code (CMAC) and Hashed Message Authentication Code (HMAC) based control message protection schemes. 4G moves wireless performance to a new level while offering speed, reliability and security on par with wired network connections. Extending this type of network service to mobile users is equivalent to moving from dial-up to broadband Internet access.

Quality of Service (QoS): In the WiMAX access protocol, outbound transmissions are broadcast to all stations in a cell or sector in a format that includes a device and a connection address [8] each station picks off and decrypts the frames addressed to it. Where each connection will use a unique encryption key. Inbound transmissions use a Request/Grant access mechanism in which a station wishing to access the inbound channel sends a request to the base station, which in turn issues a grant allowing the user exclusive use of some portion of the inbound transmission capacity. As the base station controls all inbound transmissions, it can eliminate inbound collisions and, most importantly, it can implement QoS capabilities, where more time-sensitive inbound transmissions (e.g., voice and video) are given precedence over others. Comparison of WiMAX QoS Service Capabilities

Each WiMAX connection is specified to support one of five available QoS categories:

A. Unsolicited Grant Service (UGS): Short, consistent delay service for real-time Voice over IP (VoIP) services, where a station is allocated dedicated inbound transmission capacity.

B. Real-Time Polling Service (rtPS): Another short, consistent delay service for streaming audio and video where the base station polls each user on a scheduled basis.

C. Extended Real-Time Polling Service (ertPS): Short, consistent delay service for VoIP applications with voice activity detection.

D. Non-Real-Time Polling Service (nrtPS): Prioritized variable delay data service with a minimum reserved rate for File Transfer Protocol (FTP) traffic.

E. Best Effort (BE): An IP-like best effort data service for Web surfing and general purpose data transfers.

ASPECT 3GPP-LTE Mobile WiMAX (IEEE 802.16E)

Core network UTRAN moving towards All-IP evolved-UTRA(E-UTRA) core network with IMS with SAE architecture

WiMAX forum all-IP network

Legacy GSM/GPRS/EDGE/UMTS/HSPA

IEEE 802.16 through d

Access technology: Downlink Uplink

OFDMA SC-FDMA

OFDMA OFDMA

FFT SIZE 64,128,256, 512,1024, 2048

128, 256, 512,1024, 2048

Radio access mode

TDD AND FDD TDD and FDD

Frequency band Existing(800,900,1800,1900MHz) and new frequency band( Range 800MHz-2.62GHz)

NLOS: 2-11GHz

Peak data rate DL UL

OFDMA SC-FDMA

OFDMA OFDMA

CHANNEL BANDWIDTH

scalable from 1.25 to 20MHz with system profiles 1.25, 1.4, 2.5,3,5,10,15 and 20MHz

scalable from 1.25 to 20MHz with system profiles 1.25, 2.5, 5,10 and 20 MHz

Cell radius

5 km ~20.7 km for 3.5 or 7MHz BW ~8.4 km for 5 or 10MHz BW

Cell capacity >200 users @5MHz >400 users for larger BW

100-200 users

Mobility: Speed Handover

Upto 350km/h Inter-cell soft handovers supported

Upto 120km/h Optimized hard handovers supported

Antenna scheme: Downlink Uplink No of code words

MIMO 2Tx X2 Rx 2Tx X2 Rx 2

MIMO 2Tx X 2Rx 1Tx X NRx (Collaborative) 1

Roaming New Auto through existing GSM/UMTS

Security algorithm

UEA1, UIA1, UEA2 (SNOW algorithm supporting 256 bits of keys) and UIA2

PKMv1 RSA, HMAC, AES-CCM, and PKMv2- EAP, CMAC, AES-CTR, MBS security

QoS Category Applications QoS Specifications UGS Unsolicited Grant Service

VoIP Maximum Sustained Rate • Latency Tolerance • Jitter Tolerance • Grant Interval

rtPS Real-Time Polling Service

Streaming Audio or Video

Minimum Reserved Rate • Maximum Sustained Rate • Latency Tolerance • Traffic Priority

ertPS Extended Real-Time Polling Service

VoIP with Voice Activity Detection/ Silence Suppression

• Minimum Reserved Rate • Maximum Sustained Rate • Latency Tolerance • Jitter Tolerance • Traffic Priority

nrtPS Non-Real-Time Polling Service

File Transfer Protocol (FTP)

Minimum Reserved Rate • Maximum Sustained Rate • Traffic Priority

BE Best-Effort Service

Data Transfer, Web Browsing

Maximum Sustained Rate • Traffic Priority

The QoS categories, their characteristics and targeted applications are summarized in above Table. With the range of implementation options available, WiMAX can describe networks with widely different sets of capabilities.

REFERENCES [1] fujitsu microelectronics America, ”A Comparison of Fixed and Mobile

WiMAX” http://www.fujitsu.com/us/services/ edevices/microelectronics /broadbandwireless/ , 2006,

[2] Sanida Omerovic, University of Ljubljana, Slovenia, “WiMAX Overview”

[3] Technical White Paper “Understanding WiMAX and 3G for Portable/Mobile Broadband Wireless” A Technical Overview and Comparison of WiMAX and 3G Technologies, December 2004

[4] Tejas Bhandare, Santa Clara University, “LTE and WiMAX comparison”, December 2008.

[5] i. sarris, a. r. nix, a. doufexi, “ high performance WiMAX architecture using Mimo technology in line-of-sight”

[6] Vasile Horia Muntean, Marius Otesteanu, “WiMAX versus LTE - An overview of technical aspects for Next Generation Networks technologies” IEEE 2010 .

[7] “Mobile WiMAX: The 4G Revolution Has Begun”, Version 1.0 [8] Dr. Sassan Ahmadi “Introduction to mobile WiMAX Radio Access

Technology: PHY and MAC Architecture” Wireless Standards and Technology Intel Corporation , December 7, 2006