WiMAX Fixed Vs. Mobile Mustafa Saad Mustafa Networks Eng. Dept. College of Information Engineering Al-Nahrain University Mustafa Saad Mustafa Networks Eng. Dept. College of Information Engineering Al-Nahrain University

Agenda  Introduction  Overview Of the IEEE Standard & Mainly (IEEE )  Fixed WiMAX  Mobile WiMAX  Fixed Vs. Mobile

Introduction Stands for “Worldwide Interoperability for Microwave Access”. Based on IEEE standard is the IEEE standard for Wireless Metropolitan Area Network (Wireless MAN). Specifies the air interface for fixed, portable, and mobile broadband wireless access (BWA) systems supporting multimedia services. Aims to provide wireless broadband services with a target range of up to 31 miles at a transmission rate exceeding 100 Mbps.

Introduction It is also to provide a wireless alternative to cable, DSL and T1/E1 for last mile access. The term IEEE and WIMAX are used interchangeably. WiMAX is to IEEE where Wi-Fi is to IEEE

Agenda  Introduction  Overview Of the IEEE Standard & Mainly (IEEE )  Fixed WiMAX  Mobile WiMAX  Fixed Vs. Mobile

Overview Of the IEEE Standard Designed for point-to-point (PTP) and point-to- multipoint (PTM) topologies but mainly deployed for point to multipoint topologies. It also support mesh topologies. IEEE has three major versions:  IEEE  IEEE d-2004(Fixed).  IEEE e-2005(Mobile).

IEEE Addresses fixed line of sight (LOS) connections and operates in the licensed frequency range between 10 GHz and 66 GHz. At these high frequency range (reduced risk of interference) Has a maximum coverage of 5km.

IEEE Physical layer Designed for line-of-sight propagation because the frequency range is between GHz. Single-carrier modulation is used and the air interface is called “WirelessMAN-SC”.

IEEE MAC Supports both Time Division Duplex (TDD) and Frequency Division Duplex (FDD). It uses a slotted TDMA protocol scheduled by the base terminal station to allocate capacity to subscribers. It also supports different transport technologies such as IPv4, IPv6, Ethernet, Asynchronous Transfer Mode (ATM). Provides mechanisms for authentication, key-sharing and encryption.

Agenda  Introduction  Overview Of the IEEE Standard & Mainly (IEEE )  Fixed WiMAX  Mobile WiMAX  Fixed Vs. Mobile

IEEE d “Fixed” Designed to operate in lower frequency range; 2-11 GHz. Support Non-line of sight (NLOS) operation. Operates in both licensed (3.5 GHz) and unlicensed (5.8 GHz). Operates with a range of up to 50km and data rates of up to 75Mbps.

IEEE d “Fixed” PHY Design for the 2-11 GHz range and is more complex because of interference. Three air interfaces are specified for this range, which are; I.Wireless MAN-SC uses single carrier modulation. II.Wireless MAN-OFDM uses a 256-carrier FDM. Provides multiple access to different stations through TDMA. III.Wireless MAN-OFDMA uses a 2,048-carrier OFDM scheme.

Agenda  Introduction  Overview Of the IEEE Standard & Mainly (IEEE )  Fixed WiMAX  Mobile WiMAX  Fixed Vs. Mobile

IEEE e “Mobile” Support mobility and will standardize networking between fixed base stations and mobile devices. Would enable high-speed signal handoffs necessary for communications with users moving at vehicular speeds which is below 100km/h. It will provide 70Mbps. Operates in the frequency range between 2-6 GHz.

IEEE e “Mobile” PHY The main technologies used for it’s physical layer are OFDMA and an improved version called Scalable OFDMA (SOFDMA). SOFDMA scales the number of sub-carriers in a channel with possible values of 128, 512, 1024, and 2,048.

IEEE e “Mobile” MAC It is connection oriented and supports quality of service (QoS) for stations through adaptive allocation of the uplink and downlink traffic.

Agenda  Introduction  Overview Of the IEEE Standard & Mainly (IEEE )  Fixed WiMAX  Mobile WiMAX  Fixed Vs. Mobile

Fixed Vs. Mobile I.Mobility Management and Hand Offs The simplest difference between the fixed and mobile is the fact that the mobile enables a hand- off from one base station to another as the user, in one session, moves from the coverage zone of one base station to another. This is also known as “mobility management”.

Fixed Vs. Mobile II.OFDM vs. SOFDMA Orthogonal Frequency Division Multiplexing (OFDM) breaks the wireless carrier into 256 sub-carriers. The two greatest advantages are: (a) it mitigates inter symbol interference (multipath) (b) improves propagation of the signal, especially in non-line of sight (NLOS) coverage zones.

Fixed Vs. Mobile II.OFDM vs. SOFDMA OFDMA breaks the carrier into even more sub carriers (up to 2048 sub carriers). The “mobile” WiMAX uses SOFDMA. The advantage of this is better propagation and improved building penetration. The use of OFDMA should also enable the use of smaller, less costly subscriber devices including PC cards and USB devices.

Fixed Vs. Mobile III.QoS e introduces Extended Real-Time Polling Service (ERTPS). ERTPS allows the e solution to manage traffic rates and transmission policies as well as improving latency and jitter. (VoIP) applications.

Future Works & Problems P802.16m (In progress) :Advanced Air Interface with data rates of 100 Mbit/s mobile & 1 Gbit/s fixed. With “MIMO” (Downlink 128 Mbps/20 Mhz & Uplink 56 Mbps 20 Mhz) Problems:  Wimax Availability Problem (DoS)  Authentication Problem In WiMAX (man-in-the-middle attack)  Policies (government), infrastructure(poor) and low income Mainly Security Problem Also known as Mobile WiMAX Release 2 or WirelessMAN- Advanced

References [1]. K. Fazel and S. Kaiser, M. Ergen, “Wikipedia ”, , URL: [2]. Sridhar Iyer, “WiMAX: IEEE Wireless MANs”, K R School of Information Technology, URL: [3]. AFTAB AHMAD, “WIRELESS AND MOBILE DATA NETWORKS”, Wiley & Sons, Inc., 1 st Edition, [4]. Aruleba, Olakunle Michael, “WiMAX (IEEE )”, B.Sc. Project, University of Windsor, University of Windsor [5]. Frank Ohrtman, “Fixed vs. Mobile WiMAX Mobility Monomania?”, President, WMX Systems, LLC,URL: July [6]. White Paper, “WiMAX: E vs. D The Advantages of e over d”, URL: Motorola, Inc

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