Rehab AlFallaj

 Is any type of computer network that uses wireless data connections for connecting network nodes and sharing network resources.  So, it differs than previous network with, the type of transmission media, wireless transmission media.  Microwave.  Infrared.  Laser.

 Wireless network based on its covered and its bandwidth used in its channel frequencies.  Wireless Personal Area Network (WPAN) الشبكة الشخصية المحلية اللاسلكية.  Wireless LAN الشبكة المحلية اللاسلكية.  Wireless WAN الشبكة الموسعة اللاسلكية.  Wireless Broadband الشبكة اللاسلكية المدنية عريضة النطاق.  Wireless Cellular الشبكة اللاسلكية الجوالة.

 Used to link or connect personal devices (PDA Personal Data Assistant), printers, mobile devices embedded in computers.  One hall, room  Controlled by 1 person owned the network.  Microwave, Infrared waves.

 Covers a building, or more.  Connects personal computers, Notebooks, printers, storage devices wirelessly.  Controlled by 1 person or more.  Microwave, Infrared waves.

 Covered wider geographical area, cities, countries.  Links and connects computers among different cities wirelessly by Satellite.  Controlled by international organization or government or big telecommunication companies.

 Covers a city.  Connects computers wirelessly.  Mainly used to transmit large amounts of data very fast,  Ex: Video films, Photos, websites.  Broadband microwaves, laser.  Controlled by organization or government.

 Used mostly for mobiles, but now can be used for data transmission.  Can connect computers, connect to Internet.  Can be used in a wide area.  Controlled by companies or government.

 To extend LAN.  Sometimes it is difficult to extend a wired LAN, so wireless technologies can help.  To connect two to more LANs.

 Advantages:  Decrease cost of the new extension.  Easy to change.

 Serve mobile devices, laptops, notebooks.

 Build a temporary network.  Military camps.  Relief camps.  conferences.  Usually this type of temporary networks have a changing topology ( not fixed or has a permanent topology).

 Radio and microwaves and infrared waves is more prone to the interference.  Data transmission is not %100 guaranteed.  Attenuation and fading of waves and signals may occur.  Privacy security concerns.  The limitation of the bandwidth, and the huge number of people connecting with this network demanding the need to manage and granting the right to broadcast to eliminate interference if waves.

 Usually transmission rate becomes lower (based on Nyqist rule) when huge number of Subscribers are there.  The limitation of the power that supplies wireless devices, protocols should be made based on it.  “Hidden node” and “Exposed node”.

 Add-hoc WLAN الشبكة العشوائية اللاسلكية.  Routers pass/forwards signals and data.  Service nodes.  A network with a changing and random nature.  Topology cab change  Basic Service Set (BSS) مدى الخدمة الاساسي

 Multicells wireless networks شبكة متعددة الخلايا.  Many access points AP connect computers.  These AP connected through channel or wired network “ Distributed Systems”  Extended Service Set ESS

 Institute of Electrical & Electronic Engineers IEEE, The European Telecommunications Standards Institute ETSI, and forums of companies and factories that manufacture these network devices (ex: Bluetooth forum).  204 GHz – 5 GHz frequencies.

 Bluetooth wireless network standards:  IBM, INTEL, NOKIA, Ericsson, Toshiba  Connect PDAs, printers, mobile devices embedded in computers.  Covers 1 hall, room.  Controlled by 1 person won this network.  Microwave, infrared transmission channel.

 IEEE, project  a, b, g  It is called Wi-Fi ( commercial name)  wireless LAN:  Transmission rate: 2 Mbps  Bandwidth: 2.4 GHz  b wireless LAN:  Transmission rate: 11 Mbps  Bandwidth: 2.4 GHz

 a wireless LAN:  Transmission rate: 54 Mbps  Bandwidth: 5 GHz  g wireless LAN:  Transmission rate: 54 Mbps  Bandwidth: 2.4 GHz  Compatible with b

 IEEE, project  :  Line of sight transmission rate: 134 Mbps  Bandwidth: GHz.  Wi-MAX a:  Line of sight transmission rate: 70 Mbps  Bandwidth: 2-11 GHz.

 For specific purposes, use sensing and digital controlling.  Used for Remote Sensing application, ex: factories, radar application, hospitals.  standards:  Transmission using: Ultra Wide Band (UWB), transmission with lower power with a very high broadband.  No interference and noise.

 Due to noise, interference, hidden and exposed nodes; CSMA can’t be used effectively in wireless LANs.  Aloha can be used.  Multiple Access with Collision Avoidance MACA; similar to CSMA/DA  Multiple Access with Collision Avoidance for Wireless MACAW.  Collisions can be detected at receiver device.  Transmission by Request To Send” frame (RTS) and Confirm To Send” frame (CTS).

 Waiting time after collision is equal with all waiting nodes.  ACK is used to confirm receiving the data correctly.  RTS  CTS  DATA  ACK