CIS Ch8

Global Positioning Systems (GPS)

-A wireless system that utilizes satellites to enable users to determine their position anywhere on Earth. -Supported by 24 MEO Satellites Uses of GPS -Navigating, Mapping, Surveying, 911 location -Three additional GPS Systems GLONASS, Russia 2005 Galileo, European Union 2015 Beidou, China 2020

Medium-Range Wireless Networks - Cellular Radio (Cellular telephones)

1G - used analog signals and had low bandwidth 2G - uses digital signals primarily for voice communication up to 10 Kbps 3G - uses digital signals and provides voice and data communication up to 144 Kbps Code Division Multiple Access (CDMA) Global System for Mobile Communications (GSM) 4G / Long-Term Evolution (LTE) 100 Mbps for high-mobility communications (cars) 1 Gbps for low-mobility communications (pedestrians)

Pervasive Computing Radio-Frequency Identification (RFID) - Versus bar codes

A typical bar code, known as the Universal Product Code (UPC), is made up of 12 digits that are batched in various groups. The first digit identifies the item type, the next 5 digits identify the manufacturer, and the next 5 identify the product. The last digit is a check digit for error detection.

WTM: Microwave Advantages and Disadvantages

A: High bandwidth Relatively Inexpensive D: Requires an unobstructed line of sight Susceptible to environmental interference

Pervasive Computing Radio-Frequency Identification (RFID) Two types of RFID tags:

Active RFID tags use internal batteries for power and they broadcast radio waves to a reader Passive RFID tads rely entirely on readers for their power

Short-Range Wireless Networks

Bluetooth Ultra-Wideband Near-Field Communications

WTM: Satellite Advantages and Disadvantages

Expensive Requires unobstructed line of sight Signals experience propagation delay Requires the use of encryption for security

Three Basic Types of Telecommunications Satellites

Geostationary Earth Orbit (GEO) Middle Earth Orbit (MEO) Low Earth Orbit (LEO)

WTM: Radio Advantages and disadvantages

High bandwidth Signals pass through walls Inexpensive and easy to install Creates electrical interference problems Susceptible to 'snooping' unless encrypted

Medium-Range Wireless Networks - Wireless Fidelity (Wi-Fi) - Wireless Local Area Networks (WLAN)

In a typical configuration, a transmitter with an antenna, called a wireless access point connects to a wired LAN or to satellite dishes that provide an Internet connection. A wireless access point provides service to a number of users within a small geographical perimeter (up to a couple of hundred feet), known as a hotspot.

Pervasive Computing

Invisible "everywhere computing" that is embedded in the objects around us

WTM: Infrared Advantages and disadvantage

Low to medium bandwidth Used only for short distances Requires an unobstructed line of sight

Medium-Range Wireless Networks - Wireless Mesh Networks

Mesh networks use multiple Wi-Fi access points to create a wide area network that can be quite large.

Medium-Range Wireless Networks - Wireless Fidelity (Wi-Fi) - MiFi

MiFi is a small, portable wireless device that provides users with a permanent Wi-Fi hotspot wherever they go

WTM: Radio - Satellite radio

Most radio signals can travel only 30 to 40 miles from their source Satellite radio overcomes this problem Satellite radio (or digital radio) offers uninterrupted, near CD-quality transmission that is beamed to your radio, either at home or in your car, from space.

Pervasive Computing Wireless Sensor Networks

Networks of interconnected, battery powered, wireless sensors called motes that are placed into the physical environment.

Geostationary Earth Orbit (GEO)

Orbit: 22,300 miles Number of Satellites: 8 Use: TV Signal, Internet Characteristics: -Satellites stationary relative to point on Earth -Few satellites needed for global coverage -Transmission delay (approximately .25 second) -Most expensive to build and launch -Longest orbital life (many years)

Low Earth Orbit (LEO)

Orbit: 400 - 700 miles Number of Satellites: Many Use: Telephone, Internet Characteristics: Satellites move rapidly relative to point on Earth Large number needed for global coverage Requires only low-power transmitters Negligible transmission delay Least expensive to build and launch Shortest orbital life (as low as 5 years)

Middle Earth Orbit (MEO)

Orbit: 6,434 miles Number of Satellites: 10-12 Use:Global Positioning Systems (GPS) Characteristics: -Satellites move relative to point on Earth -Moderate number needed for global coverage -Requires medium-powered transmitters -Negligible transmission delay -Less expensive to build and launch -Moderate orbital life (6-12 years)

Internet over Satellite (IoS) advantages and disadvantages

Provides Internet services to remote areas of Earth. Propagation delay. Disrupted by environmental conditions

Pervasive Computing Radio-Frequency Identification (RFID) - Versus Quick Response (QR) codes (2)

QR codes are more resistant to damage than bar codes. QR codes can be read from any direction or angle, so they are less likely to be misread.

Pervasive Computing Radio-Frequency Identification (RFID) - Versus Quick Response (QR) codes

QR codes can store much more information than bar codes. Data types stored in QR codes include numbers, text, URLs, and even Japanese characters. The size of QR codes is small because these codes store information horizontally and vertically.

Medium-Range Wireless Networks - Wireless Fidelity (Wi-Fi) -Three factors are preventing the commercial Wi-Fi market from expanding even further:

Roaming Security Cost

Wireless Computer Networks & Internet Access

Short-Range Wireless Networks Medium-Range Wireless Networks Wide-Area Wireless Networks

Wireless Devices

Three Major Advantages for Users Small enough to easily carry or wear. Sufficient computing power to perform productive tasks. Communicate wirelessly with the Internet & other devices. One Major Disadvantage for Business Workers can capture and transmit sensitive proprietary information

Medium-Range Wireless Networks - Wireless Fidelity (Wi-Fi) - Wi-Fi Direct

Wi-Fi Direct enables peer-to-peer communications, so devices can connect directly. It allows users to transfer content among devices without having to rely on a wireless antenna. It can connect pairs or groups of devices at Wi-Fi speeds of up to 250 Mbps and at distances of up to 800 feet

Wireless Transmission Media (WTM)

Wireless Media (aka, broadcast media) transmit signals without wires Major Types of Wireless Media Channels: Microwave Satellite Radio Infrared

Wide-Area Wireless Networks Wireless Broadband (or WiMax)

has a wireless access range of up to 31 miles, compared to 300 feet for Wi-Fi. has a data-transfer rate of up to 75 Mbps.

Short-Range Wireless Networks - Near-Field Communications (NFC)

has the smallest range of any short-range wireless networks it is designed to be embedded in mobile devices such as cell phones and credit cards

Short-Range Wireless Networks - Ultra-Wideband (UWB)

is a high-bandwidth wireless technology with transmission speeds in excess of 100 Mbps. this very high speed makes UWB a good choice for applications such as streaming multimedia from, say, a personal computer to a television.

Short-Range Wireless Networks - Bluetooth

is an industry specification used to create small personal area networks. a personal area network is a computer network used for communication among computer devices—for example, telephones, personal digital assistants, and smartphones—located close to one person. Bluetooth 5.0 - 50 Mbps

Medium-Range Wireless Networks - Wireless Fidelity (Wi-Fi) - Super Wi-Fi

uses the lower-frequency white spaces between television channel frequencies. these lower frequencies enable the signal to travel further and penetrate walls better than normal Wi-Fi frequencies.