Wireless Data Network PGT 316 Mobile and Wireless

Wireless Data Network PGT 316 Mobile and Wireless Communication

Objectives Describe the basic and hybrid LAN physical topologies, and their uses, advantages and disadvantages Describe the backbone structures that form the foundation for most LANs Describe the Wireless LAN 802. 11 Zig bee connections Bluetooth GPS

Simple Physical Topologies Physical topology: physical layout of nodes on a network Three fundamental shapes: Bus Ring Star May create hybrid topologies Topology integral to type of network, cabling infrastructure, and transmission media used

Bus Single cable connects all network nodes without intervening connectivity devices Devices share responsibility for getting data from one point to another Terminators stop signals after reaching end of wire Prevent signal bounce Inexpensive, not very scalable Difficult to troubleshoot, not fault-tolerant

Bus (continued)

Advantages of Bus Topology Works well for small networks Relatively inexpensive to implement Easy to add to it

Disadvantages of Bus Topology Management costs can be high Potential for congestion with network traffic

Ring

Simple Physical Topologies Physical topology Physical layout of a network A Bus topology consists of a single cable—called a bus— connecting all nodes on a network without intervening connectivity devices

Advantages of Bus Topology Works well for small networks Relatively inexpensive to implement Easy to add to it

Disadvantages of Bus Topology Management costs can be high Potential for congestion with network traffic

Simple Physical Topologies Ring topology Each node is connected to the two nearest nodes so the entire network forms a circle One method for passing data on ring networks is token passing Active topology Each workstation transmits data

Advantages of Ring Topology Easier to manage; easier to locate a defective node or cable problem Well-suited for transmitting signals over long distances on a LAN Handles high-volume network traffic Enables reliable communication

Disadvantages of Ring Topology Expensive Requires more cable and network equipment at the start Not used as widely as bus topology Fewer equipment options Fewer options for expansion to high-speed communication

Star

Simple Physical Topologies Star topology Every node on the network is connected through a central device

Star (continued) Any single cable connects only two devices Cabling problems affect two nodes at most Requires more cabling than ring or bus networks More fault-tolerant Easily moved, isolated, or interconnected with other networks Scalable Supports max of 1024 addressable nodes on logical network

Advantages of Star Topology Good option for modern networks Low startup costs Easy to manage Offers opportunities for expansion Most popular topology in use; wide variety of equipment available

Disadvantages of Star Topology Hub is a single point of failure Requires more cable than the bus

Hybrid Physical Topologies: Star-Wired Ring

Star-Wired Bus

Backbone Networks: Serial Backbone Daisy chain: linked series of devices Hubs and switches often connected in daisy chain to extend a network Hubs, gateways, routers, switches, and bridges can form part of backbone Extent to which hubs can be connected is limited

Backbone Networks: Serial Backbone (continued)

Distributed Backbone

Collapsed Backbone

Parallel Backbone

Logical Topologies Logical topology: how data is transmitted between nodes May not match physical topology Bus logical topology: signals travel from one network device to all other devices on network Required by bus, star-wired physical topologies Ring logical topology: signals follow circular path between sender and receiver Required by ring, star-wired ring topologies

802. 11 Wireless LAN Network connectivity to the legacy wired LAN Desktop with PCI 802. 11 LAN card Access Point Laptop with PCMCIA 802. 11 LAN card Provides network connectivity over wireless media An Access Point (AP) is installed to act as Bridge between Wireless and Wired Network The AP is connected to wired network and is equipped with antennae to provide wireless connectivity

802. 11 Wireless LAN Range ( Distance between Access Point and WLAN client) depends on structural hindrances and RF gain of the antenna at the Access Point To service larger areas, multiple APs may be installed with a 2030% overlap A client is always associated with one AP and when the client moves closer to another AP, it associates with the new AP (Hand-Off) Three flavors: 802. 11 b 802. 11 a 802. 11 g

Multiple Access with Collision Avoidance (MACA) other node in sender’s range sender receiver RTS other node in receiver’s range CTS data ACK Before every data transmission Sender sends a Request to Send (RTS) frame containing the length of the transmission Receiver respond with a Clear to Send (CTS) frame Sender sends data Receiver sends an ACK; now another sender can send data When sender doesn’t get a CTS back, it assumes collision

WLAN : 802. 11 b The most popular 802. 11 standard currently in deployment. Supports 1, 2, 5. 5 and 11 Mbps data rates in the 2. 4 GHz ISM (Industrial-Scientific-Medical) band

WLAN : 802. 11 a Operates in the 5 GHz UNII (Unlicensed National Information Infrastructure) band Incompatible with devices operating in 2. 4 GHz Supports Data rates up to 54 Mbps.

WLAN : 802. 11 g Supports data rates as high as 54 Mbps on the 2. 4 GHz band Provides backward compatibility with 802. 11 b equipment

Repeater A repeater receives a signal, regenerates it, and passes it on. It can regenerate and retime network signals at the bit level to allow them to travel a longer distance on the media. It operates at Physical Layer of OSI The Four Repeater Rule for 10 -Mbps Ethernet should be used as a standard when extending LAN segments. This rule states that no more than four repeaters can be used between hosts on a LAN. This rule is used to limit latency added to frame travel by each repeater.

Indoor Repeater Early 90’s Current technology

How Repeater Works

Hub Hubs are used to connect multiple nodes to a single physical device, which connects to the network. Hubs are actually multiport repeaters. Using a hub changes the network topology from a linear bus, to a star. With hubs, data arriving over the cables to a hub port is electrically repeated on all the other ports connected to the same network segment, except for the port on which the data was sent.

Sample Hub

How Hub works

Bridges are used to logically separate network segments within the same network. They operate at the OSI data link layer (Layer 2) and are independent of higher-layer protocols. The function of the bridge is to make intelligent decisions about whether or not to pass signals on to the next segment of a network. When a bridge receives a frame on the network, the destination MAC address is looked up in the bridge table to determine whether to filter, flood, or copy the frame onto another segment Broadcast Packets are forwarded

Sample Bridge

How Bridge Works

Switches are Multiport Bridges. Switches provide a unique network segment on each port, thereby separating collision domains. Today, network designers are replacing hubs in their wiring closets with switches to increase their network performance and bandwidth while protecting their existing wiring investments. Like bridges, switches learn certain information about the data packets that are received from various computers on the network. Switches use this information to build forwarding tables to determine the destination of data being sent by one computer to another computer on the network.

Switches: Dedicated Access A C’ B Hosts have direct connection to switch Full Duplex: No collisions switch Switching: A-to-A’ and B-to-B’ simultaneously, no collisions Switches can be cascaded to expand the network C B’ A’

Zig. Bee is a specification for high level communication protocols using small, low-power digital radios based on an IEEE 802 standard for personal area networks. Applications include wireless light switches, electrical meters with in-home-displays and other consumer or industrial equipment that requires short-range wireless transfer of data at relatively low rates. It is intended to be simpler and less expensive than other WPANs, such as Bluetooth by which it is targeted at radio-frequency (RF) applications that require a low data rate, long battery life, and secure networking.

Zig. Bee Application Operates in the industrial, scientific and medical (ISM) radio bands; 868 MHz in Europe, 915 MHz in the USA and Australia, and 2. 4 GHz in most jurisdictions worldwide. Data rates vary from 20 to 900 kbps. It is a low-cost, low-power, wireless mesh network standard. The low cost allows the technology to be widely deployed in wireless control and monitoring applications. Low powerusage allows longer life with smaller batteries. Mesh networking provides Backbone high reliability and more extensive networks range. Smoke detector Temperature sensor Vibration Sensor Air Conditioning Zig. Bee Coordinator

Bluetooth is the name of a wireless technology standard for connecting devices, set to replace cables. It uses radio frequencies in the 2. 4 GHz range to transmit information over short distances of generally 33 feet (10 meters) or less. By embedding a Bluetooth chip and receiver into products, cables that would normally carry the signal can be eliminated.

Bluetooth Application Cordless headset to phone connection Computer to mouse printer to video camera Synchronisation of portable devices with desktop PC Updating navigation equipment from computer route plan

Bluetooth vs. Infrared Parameter Infrared Bluetooth Physical Media Infrared RF (2. 4 GHz) Coverage Range 0 to 1 meter, line of sight 10 or 100 meter depends on device power class Maximum Data Rate 4 Mbps (16 Mbps on the way) 24 Mbps (V 3. 0 + HS) Security Physical limitations offer some built-in protection Authentication, encryption, spread spectrum Connection Type One connection only “Piconets” with several devices can be made

Bluetooth Network Architecture M S Piconet • Temporary network • Each Bluetooth device may operate as either master or slave • One device serving as master and one or more devices serving as slaves in Piconet • A frequency-hopping channel based on the address of the master defines each Piconet • Master coordinates the Piconet and slaves follow the master • Up to 8 active devices S S S M S S

WLAN vs. Bluetooth and 802. 11 Usage Scenarios Data/Voice Access Points Cable Replacement Bluetooth Bluetooth Access Point Wireless Bluetooth Ad Hoc Networking WCDMA Bluetooth

Ultra-Wideband (UWB) It is a technology for transmitting information spread over a large bandwidth (>500 MHz) that should, in theory and under the right circumstances, be able to share spectrum with other users. Regulatory settings of FCC in United States are intended to provide an efficient use of scarce radio bandwidth while enabling both high data rate "personal area network" (PAN) wireless connectivity and longer-range, low data rate applications as well as radar and imaging systems.

MB-OFDM UWB vs. DS-UWB Signal Band Group 2 Band Group 1 Band #2 Band #1 Band #4 Band #3 Band #5 Band Group 3 Band #6 Band #7 Band #8 Band #9 Band Group 4 Band #10 Band #11 Band Group 5 Band #12 Band #14 Band #13 Freq 3432 MHz Low 4488 MHz High 3960 MHz Mid 5016 MHz Low 5544 MHz Mid 6072 MHz High 6600 MHz Low 7128 MHz Mid 7856 MHz High 8184 MHz Low 8712 MHz Mid 9240 MHz High 9768 MHz Low 10296 MHz Mid 3. 1 to 10. 6 GHz (750 MHz) MB-OFDM UWB Signal High Band Low Band GHz 3 4 5 6 7 8 9 10 GHz 3 DS-UWB 4 5 6 7 8 9 10

Wireless Universal Serial Bus (WUSB) A short-range, high-bandwidth wireless radio communication protocol created by the Wireless USB Promoter Group. It is based on the Wi. Media Alliance's Ultra-Wide. Band (MBOFDM UWB) common radio platform, which is capable of sending 480 Mbit/s at distances up to 3 meters and 110 Mbit/s at up to 10 meters. It was designed to operate in the 3. 1 to 10. 6 GHz frequency range, although local regulatory policies may restrict the legal operating range for any given country. It is used in game controllers, printers, scanners, digital cameras, portable media players, hard disk drives and flash drives.

Sample wireless USB

Various Comparisons

Various Comparisons (cont. )

Wide Area Network (WAN) Wi. MAX = Worldwide Interoperability for Microwave Access • Wi. MAX networks How Wi. MAX Works – broadband wireless networks that are based on the IEEE 802. 16 standard. • This technology promises – High speed of broadband service: 75 Mbps. – Wireless rather than wired access. – Broad Coverage: 50 km. ISP Network Home LAN Internet Backbone Wi. MAX IEEE 802. 16 Transmitter

Wi. MAX System Access Switching Transport Legacy Public Switched Telephone Networks (PSTN) Switching Softswitch (Switching) Wi. MAX Phone Wi. MAX Base Station (Access) IP transport Access Wi. MAX Phone Wi. MAX Base Station (Acess) Wi. MAX as PSTN and cell phone bypass TVo. IP Server TV or video monitor Wi. MAX Base Station (Access) IP transport Wi. MAX Base Station (Access) TV or video Monitor Wi. MAX as cable or satellite TV bypass Wi. MAX Phone Wi. MAX (Transport-replaces IP backbone) Wi. MAX Base Station (Access) Wi. MAX Base Station (Acess) Wi. MAX as PSTN and cell phone bypass Wi. MAX Phone

Broadband Wireless Access (BWA) Systems IEEE Standard for Local and metropolitan area networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems IEEE Std 802. 16 -2001 (non-active) IEEE Std 802. 16 a (non-active) IEEE Std 802. 16 c (non-active) IEEE Std 802. 16 -2004 (active) IEEE Std 802. 16 e-2005 and IEEE Std 802. 16 -2004/Cor 1 -2005 (active) (fixed and mobile BWA systems) IEEE Std 802. 16 f-2005 (active) (management info base [MIB]) IEEE Std 802. 16. 2 -2004 (active) (coexistence of fixed BWA systems)

Broadband Wireless Access (BWA) Systems (cont. ) IEEE Standard for Local and metropolitan area networks Part 16: Air Interface for Fixed Broadband Wireless Access Systems IEEE Std 802. 16/Conformance 01 -2003 (active) IEEE Std 802. 16/Conformance 02 -2003 (active) IEEE Std 802. 16/Conformance 03 -2003 (active)

IEEE 802. 16: Frequency Bands 10 – 66 GHz licensed bands Provides a physical environment where, due to the short wavelength, line-of-sight (LOS) is required and multipath is negligible. Channel bandwidths of 25 MHz to 28 MHz are typical. With raw data rates in excess of 120 Mb/s, this environment is well suited for point-to-multipoint (PMP) access serving applications from small office / home office (SOHO) through medium to large office applications. The single-carrier modulation air interface specified in IEEE 802. 16 -2004 for 10 – 66 GHz is known as the “Wireless. MAN-SC” air interface.

IEEE 802. 16: Frequency Bands Frequencies below 11 GHz Provides a physical environment where, due to the longer wavelength, LOS is not necessary and multipath may be significant. The ability to support near-LOS and non-LOS (NLOS) scenarios requires additional PHY functionality, such as the support of advanced power management techniques, interference mitigation/coexistence, and multiple antennas. Additional MAC features such as mesh topology and automatic repeat request (ARQ) are introduced.

IEEE 802. 16: Frequency Bands License-exempt frequencies below 11 GHz (5 – 6 GHz) The physical environment is similar to that of the licensed bands (below 11 GHz) in the same frequency range. However, the license-exempt nature introduces additional interference and co-existence issues, whereas regulatory constraints limit the allowed radiated power. Additionally, the PHY and MAC introduce mechanisms such as dynamic frequency selection (DFS) to detect and avoid interference.

IEEE 802. 16: Frequency Bands (2 to 6 GHz) Extracted from http: //electronicdesign. com/site-files/electronicdesign. com /files/archive/electronicdesign. com/files/32/9998/figure_02. gif White Paper Wi. MAX Spectrum - Fujitsu

Wi. MAX System: General Features Subsystems: A Wi. MAX tower (base station) similar in concept to a cell-phone tower — A single Wi. MAX tower can provide coverage to a very large area as big as ~8, 000 square km. A Wi. MAX client terminal The terminal receiver and antenna could be a small box or Personal Computer Memory card, or they could be built into a laptop the way Wi. Fi access is today Frequency bands (GHz): 2 to 11 and 10 to 66 (licensed and unlicensed bands) IEEE 802. 16 standards define both MAC and PHY layer and allows multiple PHY layer specifications

Basic Data on IEEE 802. 16 Standards 802. 16 -2004 802. 16 e-2005 Status Completed Dec 2001 Completed Jun 2004 Completed Dec 2005 Frequency band 10 -66 GHz 2 -11 GHz for fixed, 2 -6 GHz for mobile applications Application Fixed LOS Fixed NLOS Fixed and Mobile NLOS Transmission scheme Single carrier only Single carrier, 256 OFDM or 2048 OFDM Single carrier, 256 OFDM or scalable OFDM with 128, 512, 1024 or 2048 sub-carrier Modulation QPSK, 16 QAM, 64 QAM Gross data rate 32 -134. 4 Mbps 1 -75 Mbps Multiplexing Burst TDM/TDMA/OFDMA Channel BW 20, 25, 28 MHz 1. 75, 3. 5, 7, 14, 1. 25, 5, 10, 15, 8. 75 MHz 1. 75, 3. 5, 7, 14, 1. 25, 5, 10, 15, 8. 75 MHz Wi. MAX Implementation None 256 – OFDM as Fixed Wi. Max Scalable OFDMA as Mobile Wi. Max Source : www. wimax. com

Fixed vs. Mobile Wi. MAX Fixed Mobile Access type Fixed and nomadic Mobile, portable, nomadic and fixed Devices Outdoor and indoor subscriber units Devices Laptop and PDA cards and modules Stand-alone subscriber units for fixed access Mobile data devices (phones, MP 3 players, Ultra Mobile PCs, game consoles, other Consumer electronic devices) Standard IEEE 802. 16 -2004 IEEE 802. 16 e-2005 Multiplexing OFDM, OFDMA with mobility support Channel size range 3. 5, 7, 10 MHz (approved profiles) 5, 7, 8. 75, 10 MHz (approved profiles) Frequency bands 3. 4 -3. 6 GHz 5. 7 -5. 8 GHz 2. 3 -2. 4 GHz (Band Classes 1, 2) 2. 496 -2. 69 GHz (Band Class 3) 3. 4 -3. 8 GHz (Band Classes 4, 5) * Sub 1 GHz under investigation Release 1. 0

Comparison of Mobile Internet Access Methods

GPS Overview • The Global Positioning System (GPS) is a satellite-based navigation system that was developed by the U. S. Department of Defense (Do. D) in the early 1970 s. • Initially, GPS was developed as a military system to fulfill U. S. military needs. However, it was later made available to civilians, and is now a dual-use system that can be accessed by both military and civilian users. • GPS provides continuous positioning and timing information, anywhere in the world under any weather conditions. Because it serves an unlimited number of users as well as being used for security reasons, GPS is a one-way-ranging (passive) system. That is, users can only receive the satellite signals.

GPS Overview (cont. ) • GPS consists, nominally, of a constellation of 24 operational satellites. This constellation, known as the initial operational capability (IOC), was completed in July 1993. • GPS satellites are arranged so that four satellites are placed in each of six orbital planes. With this constellation, four to ten GPS satellites will be visible anywhere in the world, if an elevation angle of 10° is considered. • Only four satellites are needed to provide the positioning, or location information.

GPS Overview (cont. ) • GPS satellite orbits are nearly circular (an elliptical shape with a maximum eccentricity is about 0. 01), with an inclination of about 55° to the equator. • The semi-major axis of a GPS orbit is about 26, 560 km (the satellite altitude of about 20, 200 km above the Earth’s surface) • The corresponding GPS orbital period is about 12 sidereal hours (~11 hours, 58 minutes). • GPS consists of three segments: the space segment, the control segment, and the user segment.

GPS Segments Every GPS Satellite transmits a signal which consists of 2 component • 2 sine waves (carrier frequencies) • 2 digital codes • A navigation message Download Upload (L-band) (S-band) Download (L-band) Space Segment (24 -satellite constellation) Download (L-band) Upload (S-band) GPS receiver aided GPS receiver aided Control Segment User Segment

GPS Segments (cont. ) • The navigation message contains, along with other information, the coordinates (the location) of the satellites as a function of time. • The transmitted signals are controlled by highly accurate atomic clocks onboard the satellites. • The control segment of the GPS system consists of a worldwide network of tracking stations, with a master control station (MCS) located in the United States at Colorado Springs, Colorado.

GPS Segments (cont. ) The primary task of the operational control segment is tracking the GPS satellites in order to determine and predict satellite locations, system integrity, behaviour of the satellite atomic clocks, atmospheric data, the satellite almanac, and other considerations. • This information is then packed and uploaded into the GPS satellites through the S-band link. • The user segment includes all military and civilian users. • With a GPS receiver connected to a GPS antenna, a user can receive the GPS signals, which can be used to determine his or her position anywhere in the world.

THANK YOU Q&A Prepared by Emi Izhanizam Azmi FTK Electronic Uni. MAP