Wireless Communication

Learning Objectives: By the end of this topic you should be able to: describe wireless communication methods, describe wireless communication methods, describe typical applications of wireless communications, describe typical applications of wireless communications, describe the advantages & disadvantages of wireless communications. describe the advantages & disadvantages of wireless communications.

Task Using ‘study buddies’ : 1.Write down two communications technologies that don’t use cables[30 sec] 2.Exchange with another group and add your two to their list (if yours are different)[30 sec] 3.Continue until your list returns[2 mins]

Wireless Technologies All optical technologies: All optical technologies: infra red, fibre optic, lasers infra red, fibre optic, lasers Wi-Fi Wi-Fi Bluetooth Bluetooth mobile ‘phone mobile ‘phone GSM, GPRS, 3G GSM, GPRS, 3G satellite satellite

Bluetooth uses radio waves to tansmit data uses radio waves to tansmit data range of a Bluetooth device ~10m, range of a Bluetooth device ~10m, very weak signals of 1 milliwatt (‘phones ~ 3 watts) very weak signals of 1 milliwatt (‘phones ~ 3 watts) bandwidth ~2Mbps bandwidth ~2Mbps proposed Bluetooth 3.0 protocol 480 Mbps bandwith proposed Bluetooth 3.0 protocol 480 Mbps bandwith auto-detection of other Bluetooth devices auto-detection of other Bluetooth devices no expertise required - makes its own connections no expertise required - makes its own connections Bluetooth headset connection to mobile ‘phone Bluetooth headset connection to mobile ‘phone ‘hands-free’ calls ‘hands-free’ calls use mobile ‘phone as modem for laptop computer use mobile ‘phone as modem for laptop computer transfer files between devices transfer files between devices images, MP3s, etc between ‘phones, PDAs and computers, images, MP3s, etc between ‘phones, PDAs and computers,

Bluetooth Advantages widely available widely available on portable devices on portable devices doesn’t require line of sight doesn’t require line of sight pass key can be used pass key can be used to prevent non-authorised devices connecting to prevent non-authorised devices connecting Disadvantages low bandwidth slow transfer of data 10m maximum range only connect to one device at a time can’t use headset as well as laptop connected to mobile ‘phone

Wi-Fi most common wireless networking, most common wireless networking, most laptops already come with a WiFi card built in most laptops already come with a WiFi card built in uses radio waves to transmit data uses radio waves to transmit data also known as wireless protocol also known as wireless protocol 3 main variants: b, g, n 3 main variants: b, g, n computers can be up to 100 feet apart computers can be up to 100 feet apart bandwidth from 10Mbps (802.11b) to 54Mbps (802.11g) bandwidth from 10Mbps (802.11b) to 54Mbps (802.11g) n will give bandwidth >200Mbps (& greater distance) n will give bandwidth >200Mbps (& greater distance) need wireless access point connected to network need wireless access point connected to network wireless card automatically detects & connects to access point wireless card automatically detects & connects to access point a network connection will be established. a network connection will be established.

Wi-Fi Typical applications: connect laptops to an organisations network connect laptops to an organisations network most laptops already come with a wireless NIC built in most laptops already come with a wireless NIC built in laptops connecting to the Internet using wireless ‘hotspots’ laptops connecting to the Internet using wireless ‘hotspots’ Internet cafés, hotels, pubs, airports, train stations Internet cafés, hotels, pubs, airports, train stations laptops connecting to home networks laptops connecting to home networks to enable sharing of Internet connection, printers, music …. to enable sharing of Internet connection, printers, music …. PCs with wireless NICs able to connect to a network PCs with wireless NICs able to connect to a network where cabling would be expensive or difficult to install where cabling would be expensive or difficult to install mobile ‘phones & PDAs able to access the Internet mobile ‘phones & PDAs able to access the Internet without using expensive mobile data tariffs (charged per Mb) without using expensive mobile data tariffs (charged per Mb) printers (& games consoles) connected to wireless network printers (& games consoles) connected to wireless network

Wi-Fi Advantages no need to use cables no need to use cables portable devices not limited to one location for network portable devices not limited to one location for network allows ad-hoc networking allows ad-hoc networking network reaches outdoors network reaches outdoors social/corporate events social/corporate events no line of sight required no line of sight required no expensive mobile data no expensive mobile data bandwidth sufficient for Internet communication bandwidth sufficient for Internet communication worldwide standard worldwide standard any laptop can connect to any wireless network any laptop can connect to any wireless network Disadvantages  bandwidth restricive for some network communications especially with many users multimedia streaming videoconferencing  restricted range (~30m)  security issues susceptible to hacking WEP key required to access  signal strength affected by walls, interference …