Lecture-1bPresented By Laiq Akhtar

Introduction To WiMAX & Broadband Access Technologies

Understanding theWiMAX Technology

A WiMAX base station is connected to public networks using optical fiber, cable, microwave link, or any other high-speed point-to-point(P-P) connectivity, referred as a backhaul.

WiMAX should use point-to-point antennas as a backhaul to connect aggregate subscriber sites to each other and tobase stations across long distances.

The working of a basic WiMAX system.

A base station serves subscriber stations (also called customer premise equipment [CPE] for obvious reasons) using non-line-of-sight(NLOS)

or line-of-sight (LOS) point-to-multi-point connectivity,

and this connection is referred to as the last mile.

The working of a basic WiMAX system.

Ideally, WiMAX should use NLOS point-to-multi-point antennas to connect residential or business subscribers to the base station

A subscriber station typically serves a building (business or residence)using wired or wireless LAN.

The working of a basic WiMAX system.

Typically, a WiMAX system consists of two parts’ a WiMAX base station and a WiMAX receiver (also referred as CPE).

WiMAX At PTCL

Showing ODU and IDU connectivity of a single sector

Figure Intro - AN-100U Terminal: The AN-100U consists of an indoor terminal (IDU)

and outdoor transceiver and antenna (ODU)

BASE TRANSCIEVER STATION

 IDU BTS REDMAX

System Capability: LOS, Optical LOS, non LOS Cell-based point-to-multipoint

RF Band: 3.4-3.6 GHz Modulation/Coding Rates: Auto-select modulation:

BPSK, QPSK, 16 QAM, 64 QAM

Range: LOS: PTP - Over 28 mi (45 km);

PMP - 12 mi (20km)NLOS: 1-2 mi (1.7 - 3.3 km) (QPSK 3/4 @ 70% coverage) 0.5 - 1 mi (0.8 - 1.7 km) (16QAM 3/4 @ 90% coverage)

REDMAX BTS (AN-100UX) System Specifications( PTCL)

A WiMAX receiver, which is also referred as CPE, may have a separate antenna (i.e., receiver electronics and antenna are separate modules) or could be a stand-alone box or a PCMCIA card that sits in a laptop or computer.

Access to a WiMAX base station is similar to accessing a wireless access point (AP) in a Wi-Fi network, but the coverage is MORE.

WiMAX Receiver

WiMAX Receiver

WiMAX can provide two flavors of wireless services, depending on the frequency range of operation. These frequency ranges are

10 to 66 GHz and 2 to 11 GHz. The microwave frequencies below 10 GHz are referred

to as centimeter bands. Above 10 GHz, they are known As millimeter bands

Millimeter bands have much wider allocated channel bandwidths to accommodate the larger data capacities that are suitable for high data-rate, LOS backhauling applications.

Flavors of WiMAX

Centimeter bands are best for multi-point, near-line-of-sight, tributary, and last mile distribution.

Line-of-Sight The original 802.16 standard operates 10 to 66 GHz frequency band LOS towers. The LOS access service employs a dish

antenna that points straight at the WiMAX tower from a rooftop or pole.

Flavors of WiMAX

Non-Line-of-Sight The 802.16a extension, ratified in January 2003,

uses a lower frequency of 2 to 11 GHz, enabling NLOS connections.

This was a major breakthrough in wireless broadband access because LOS between

transmission point and the receiving antenna is not necessary. With 802.16a, more customers can be connected to a single tower, substantially

reducing service costs.

Flavors of WiMAX

The NLOS access service is very similar to Wi-Fi, in which a small antenna on a computer connects to the tower.

Lower-frequency transmissions are not as easily disrupted by physical obstructions as the high-frequency transmissions, and they are better able to diffract, or bend, around obstacles.

Based on this principle, WiMAX uses a lower frequency range of 2 GHz to 11 GHz (similar to Wi-Fi) in this mode.

NLOS-style access will be limited to a radius between 4 to 6 mi (perhaps 25 sq mi or 65 sq km of coverage, which is similar in range to a cell phone zone).

Flavors of WiMAX

The WiMAX family of standards addresses two types of usage models:

a fixed-usage model (IEEE 802.16-2004) and a portable usage model. ORmobile, nomadic,and fixed wireless access systems.

Flavors of WiMAX

The basic feature that differentiates these system is the ground speed . Based on mobility, wireless access

can be divided into four classes: stationary (0 km/hr), pedestrian (up to 10 km/hr), and vehicular (sub classified as “typical” up to 100

km/hr and “high speed” up to 500 km/hr).

Types of WiMAX

A mobile wireless access system is one that can address the vehicular class,

whereas the fixed serves the stationary and pedestrian classes.

the nomadic wireless access system, which is referred to as a system that works as a fixed wireless access system but can change its location. , i.e., the office during daytime, and moving to another location, i.e., the residence in the evening.

Types of WiMAX

Portable or Mobile The 802.16a extension, ratified in January 2003,

uses a lower frequency of 2 to 11 GHz, enabling NLOS connections. The latest 802.16e provides by working on

developing a specification to enable mobile 802.16 clients.

These clients will be able to hand off between 802.16 base stations, enabling users to roam between service areas.

Types of WiMAX

two cases of portability: full mobility or limited mobility.

The simplest case of portable service (referred to as Nomadicity ) involves a user transporting an 802.16 modem to a different location.

in this scenario the user re-authenticates and manually reestablishes new IP connections and is afforded broadband service at the visited location.

Types of WiMAX

In the fully mobile scenario, user expectations for connectivity are comparable to facilities available in third-generation (3G) voice/data systems.

Users may move around while engaged in a broadband data access or multimedia streaming session.

Mobile wireless access systems need to be robust against rapid channel variation to support vehicular speeds.

Types of WiMAX