Wireless Communications and Mobile Computing PDF

Wireless Communications And mobile computing (CoSc3034) 23/11/2024 1 Course contents  Chapter One: Introduction  Chapter Two: Mobile computing  Chapter Three: Mobile Operating systems ...

Wireless Communications And mobile computing (CoSc3034) 23/11/2024 1 Course contents  Chapter One: Introduction  Chapter Two: Mobile computing  Chapter Three: Mobile Operating systems  Chapter Four: Wireless networks principles  Chapter Five: Wireless Basics  Chapter Six: Frequency allocation & regulation  Chapter Seven: Cellular Networks 23/11/2024 2  Chapter One: Introduction Topics to be covered Introduction to Wireless communication and Mobile Computing Types of Services Wireless Vs Mobile  Applications 23/11/2024 3  Introduction to Wireless communication and Mobile Computing Wireless Communication Wireless Communication is a method of transmitting information from one point to other, without using any connection like wires, cables or any physical medium. Generally, in a communication system, information is transmitted from transmitter to receiver that are placed over a limited distance. With the help of Wireless Communication, the transmitter and receiver can be placed anywhere between few meters (like a T.V. Remote Control) to few thousand kilometres (Satellite Communication). 23/11/2024 4  Cont’d… If there is no physical medium, then how does wireless communication transmit signals? Even though there are no cables used in wireless communication, the transmission and reception of signals is accomplished with Antennas. Antennas are electrical devices that transform the electrical signals to radio signals in the form of Electromagnetic (EM) Waves and vice versa. These Electromagnetic Waves propagates through space. Hence, both transmitter and receiver consists of an antenna. Electromagnetic Waves (usually Radio Waves) are used in wireless communication to carry the signals. 23/11/2024 6  Mobile Computing Mobile Computing is a technology that provides an environment that enables users to transmit data from one device to another device without the use of any physical link or cables. It allows transmission of data, voice and video via a computer or any other wireless-enabled device without being connected to a fixed physical link.  In this technology, data transmission is done wirelessly with the help of wireless devices such as mobiles, laptops etc.  It support accessing data from any remote locations without being present there physically.  It provides a vast coverage diameter for communication.  It is one of the fastest and most reliable sectors of the computing technology field. The main concept mobile computing can be divided into three:  Mobile communication  Mobile hardware  Mobile software 23/11/2024 7  Cont’d… Mobile Communication It specifies a framework that is responsible for the working of mobile computing technology. In this case, mobile communication refers to an infrastructure that ensures seamless and reliable communication among wireless devices. This framework ensures the consistency and reliability of communication between wireless devices. The mobile communication framework consists of : protocols, services, bandwidth, and portals necessary to facilitate and support the stated services. are responsible for delivering a smooth communication process. 23/11/2024 8  Cont’d… Mobile hardware  consists of mobile devices or device components that can be used to receive or access the service of mobility. Examples of mobile hardware can be smartphones, laptops, portable PCs, tablet PCs, Personal Digital Assistants, etc. 23/11/2024 9  Cont’d… Mobile software is a program that runs on mobile hardware.  designed to deal capably with the characteristics and requirements of mobile applications.  the operating system for the appliance of mobile devices.  an essential component that operates the mobile device. 23/11/2024 10 Types of Services Broadcast: The first wireless service was broadcast radio. Properties information is only sent in one direction transmitted information is the same for all users. information is transmitted continuously. Transmitter does not need to have any knowledge or consideration about the receivers Simplex mode of data transmission Number of users does not matter 23/11/2024 11  Paging unidirectional wireless communications systems. Properties  user can only receive information, but cannot transmit.  The information is intended for, and received by, only a single user.  The amount of transmitted information is very small.  used by doctors, police allowing them to react to emergencies in shorter time.  better area coverage 23/11/2024 12  Cellular Telephony most important form of wireless communications. Properties  information flow is bidirectional.(full duplex) 23/11/2024 13 Trunked radio there is no connection between the wireless system and the PSTN; it allows the communications of closed user groups. Obvious applications include police departments, fire departments, taxis, and similar Services Group calls: several users simultaneously, or several conference call between multiple users of the system. Call priorities: enable the prioritization of calls and allow dropping a low- priority call in favor of a high-priority one. Relay networks: the range of the network can be extended by using each Mobile Station (MS) as a relay station for other MSs. 23/11/2024 14  Cordless telephony describes a wireless link between a handset and a BS that is directly connected to the public telephone system. main difference from a cellphone:  is associated with, and can communicate with, only a single BS  thus no mobile switching center; rather, the BS is directly connected to the PSTN. Properties  no need to find out the location of the MS. Similarly, there is no need to provide for handover between different BSs.  There is no central system, there is no need for (and no possibility for) frequency planning.  there are no network operators that can charge fees for connections from the MS to the BS; rather, the only occurring fees are the fees from the BS into the PSTN. 23/11/2024 15  Wireless Local Area Networks (WLANs) very similar to that of cordless phones connecting a single mobile user device to a public landline system. Laptop -to- Internet. main advantage is convenience for the user, allowing mobility. WLANs can even be used for connecting fixed-location computers (desktops) A major difference between wireless LANs and cordless phones is the required data rate  Cordless 64kbps  more than 700kbps for WLAN 23/11/2024 16 WLAN….. A number of standards have been developed for WLAN, all of which carry the identifier IEEE 802.11. The original IEEE 802.11 standard 1Mbit/s, The very popular 802.11b standard (also known under the name WiFi) allows up to 11Mbit/s and the 802.11a standard extends that to 55Mbit/s. Even higher rates are realized by the 802.11n standard that was introduced in 2008/2009. WLAN devices can, in principle, connect to any BS (access point) that uses the same standard. 23/11/2024 17  Personal Area Network (PAN) coverage area even smaller than that of WLANs, number of standards for PANs have been developed by the IEEE 802.15 group One of the most common real-world examples of a PAN is the connection between a Bluetooth earpiece and a smartphone. PANs can also connect laptops, tablets, printers, keyboards, and other computerized devices. PAN network connections can either be wired or wireless. PAN intended for simple “cable replacement” duties. For example, Bluetooth standard allow to connect a hands-free headset to a phone without requiring a cable. In that case, the distance between the two devices is less than a meter. In such applications, data rates are fairly low (