EContent_11_2024_10_15_02_14_40_UNIT2newpptx__2024_08_08_10_16_53.pptx

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1. Diploma- C.E. Prof. Rushi Raval Unit no:-2 Mobile Computing [09CE1501] Wireless Transmission Fundamentals

2. TCP/IP protocol suite What is a Protocol ? A protocol is a set of rules that govern how systems communicate. For networking they govern how  data is transferred  from one system to another. What is a Protocol Suite ? A protocol suite is a collection of protocols that are designed to work together .

3. TCP/IP protocol suite

4. TCP/IP protocol suite TCP/IP specifies how data is exchanged over the internet by providing end-to-end communications that identify how it should be broken into packets, addressed, transmitted, routed and received at the destination. TCP defines how applications can create channels of communication across a network. IP defines how to address and route each packet to make sure it reaches the right destination. TCP/IP functionality is divided into four layers, each of which include specific protocols .

5. TCP/IP protocol suite - Layers Application layer: The application layer  provides applications with standardized data exchange. Its protocols include the Hypertext Transfer Protocol (HTTP), File Transfer Protocol (FTP), Post Office Protocol 3 (POP3), Simple Mail Transfer Protocol (SMTP) and Simple Network Management Protocol (SNMP). Transport Layer: The transport layer  is responsible for maintaining end-to-end communications across the network. The transport protocols include Transmission control protocol (TCP) and User Datagram Protocol (UDP ).

6. TCP/IP protocol suite - Layers Network Layer: The network layer , also called the internet layer, deals with packets and connects independent networks to transport the packets across network boundaries. The network layer protocols are the IP and the Internet Control Message Protocol (ICMP). Physical Layer: The physical layer  consists of protocols that operate only on a link. The protocols in this layer include Ethernet for local area networks (LANs) and the Address Resolution Protocol (ARP ).

7. OSI Model

8. OSI Model – Physical Layer 1. Physical Layer (Layer 1) : The lowest layer of the OSI reference model is the physical layer. It is responsible for the actual physical connection between the devices. The physical layer contains information in the form of  bits. The functions of the physical layer are : Bit synchronization:  The physical layer provides the synchronization of the bits by providing a clock. Bit rate control:  The Physical layer also defines the transmission rate i.e. the number of bits sent per second. Physical topologies:  Physical layer specifies the way in which the different, devices/nodes are arranged in a network

9. OSI Model – Data link Layer 2. Data Link Layer (DLL) (Layer 2) : The data link layer is responsible for the node to node delivery of the message. The main function of this layer is to make sure data transfer is error free from one node to another, over the physical layer. The functions of the data Link layer are : Framing:  It provides a way for a sender to transmit a set of bits that are meaningful to the receiver. Physical addressing:  After creating frames, Data link layer adds physical addresses (MAC address) of sender and/or receiver in the header of each frame. Error control:  Data link layer provides the mechanism of error control in which it detects and retransmits damaged or lost frames. Flow Control: The data rate must be constant on both sides .

10. OSI Model – Network Layer 3. Network Layer (Layer 3) : Network layer works for the transmission of data from one host to the other located in different networks. It also takes care of packet routing i.e. selection of the shortest path to transmit the packet, from the number of routes available. The sender & receiver’s IP address are placed in the header by network layer. The functions of the Network layer are : Routing:  The network layer protocols determine which route is suitable from source to destination. Logical Addressing:  In order to identify each device on internetwork uniquely, network layer defines an addressing scheme. The sender & receiver’s IP address are placed in the header by network layer .

11. OSI Model – Transport Layer 4. Transport Layer (Layer 4) : Transport layer provides services to application layer and takes services from network layer. It is responsible for the End to End delivery of the complete message. Transport layer also provides the acknowledgment of the successful data transmission and re-transmits the data if an error is found. Transport Layer reads the port number from its header and forwards the Data which it has received to the respective application. The functions of the transport layer are : Segmentation and Reassembly: at sender breaks the message into smaller segments, at destination station reassembles the message. Service Point Addressing: transport layer header includes a type of address called port address. 

12. OSI Model – Session Layer 5. Session Layer (Layer 5) : This layer is responsible for establishment of connection, maintenance of sessions, authentication and also ensures security. The functions of the session layer are : Session establishment, maintenance and termination:  The layer allows the two processes to establish, use and terminate a connection. Synchronization :  This layer allows a process to add checkpoints which are considered as synchronization points into the data. Dialog Controller :  The session layer allows two systems to start communication with each other in half-duplex or full-duplex .

13. OSI Model – Presentation Layer 6. Presentation Layer (Layer 6) : Presentation layer is also called the  Translation layer . The data from the application layer is extracted here and manipulated as per the required format to transmit over the network. The functions of the presentation layer are : Translation :  For example, ASCII values to char. Encryption/ Decryption :  Data encryption translates the data into another form or code. The encrypted data is known as the cipher text and the decrypted data is known as plain text. Compression:  Reduces the number of bits that need to be transmitted on the network .

14. OSI Model – Application Layer 7. Application Layer (Layer 7) : These applications produce the data, which has to be transferred over the network. This layer also serves as a window for the application services to access the network and for displaying the received information to the user. Ex: Application – Browsers, Skype Messenger etc. The functions of the Application layer are : Network Virtual Terminal FTAM-File transfer access and management Mail Services Directory Services

15. Modulation What is modulation? Modulation is a process through which audio, video, image or text information is added to an electrical or optical carrier signal to be transmitted over a telecommunication or electronic medium. Modulation enables the transfer of information on an electrical signal to a receiving device that demodulates the signal to extract the blended information .

16. Modulation Techniques

17. Modulation Techniques Amplitude modulation (AM) the amplitude of the carrier wave is varied in proportion to the message signal, and the other factors like frequency and phase remain constant. Frequency modulation  (FM) varies the frequency of the carrier in proportion to the message or data signal while maintaining other parameters constant. Phase modulation , the carrier phase is varied in accordance with the data signal. when the phase is changed it also affects the frequency, so this modulation also comes under frequency modulation .

18. Multiple Access Techniques In wireless communication systems, it is often desirable to allow the subscriber to send information simultaneously from the mobile station to the base station The main aim in the cellular system design is to be able to  increase the capacity of the channel , i.e., to handle as many calls as possible in a given bandwidth. There are several different ways to allow access to the channel. Frequency division multiple-access (FDMA) Time division multiple-access (TDMA) Code division multiple-access (CDMA )

19. Multiple Access Techniques

20. Frequency division multiple-access (FDMA) FDMA is the basic technology for advanced mobile phone services. The features of FDMA are as follows. FDMA allots a different sub-band of frequency to each different user to access the network. If FDMA is not in use, the channel is left idle instead of allotting to the other users. The base station BS and mobile station MS, transmit and receive simultaneously and continuously in FDMA .

21. Time Division Multiple Access (TDMA) In the cases where continuous transmission is not required, there TDMA is used instead of FDMA. TDMA shares a single carrier frequency with several users where each users makes use of non-overlapping time slots. Data transmission in TDMA is not continuous, but occurs in bursts. Hence handoff process is simpler. TDMA has an advantage that is possible to allocate different numbers of time slots per frame to different users .

22. Code Division Multiple Access (CDMA) Multiple access where several transmitters use a single channel to send information simultaneously. In CDMA every user uses the full available spectrum instead of getting allotted by separate frequency. CDMA is much recommended for voice and data communications. While multiple codes occupy the same channel in CDMA, the users having same code can communicate with each other. CDMA offers more air-space capacity than TDMA .

23. WAP architecture

24. WAP architecture WAP is Optimized for: Low Bandwidth Low Display Capability Low memory Application Layer Wireless Application Environment  (WAE). This layer is of most interest to content developers because it contains among other things, device specifications, and the content development programming languages, WML, and WMLScript .

25. WAP architecture Session Layer Wireless Session Protocol (WSP). Unlike HTTP, WSP has been designed by the WAP Forum to provide fast connection suspension and reconnection. Transaction Layer Wireless Transaction Protocol (WTP). The WTP runs on top of a datagram service, such as User Datagram Protocol (UDP) It is part of the standard suite of TCP/IP protocols used to provide a simplified protocol suitable for low bandwidth wireless stations .

26. WAP architecture Security Layer Wireless Transport Layer Security (WTLS). WTLS incorporates security features that are based upon the established Transport Layer Security (TLS) protocol standard. It includes data integrity checks, privacy, service denial, and authentication services . Transport Layer Wireless Datagram Protocol (WDP). The WDP allows WAP to be bearer-independent by adapting the transport layer of the underlying bearer. The WDP presents a consistent data format to the higher layers of the WAP protocol stack. Each of these layers provides a well-defined interface to the layer above it. This means that the internal workings of any layer are transparent or invisible to the layers above it .

27. VoIP Voice over Internet Protocol (VoIP) , is a technology that allowing you to make voice calls over a broadband Internet connection instead of a analog (regular) phone line. Some VoIP services allow you to call people using the same service, but others may allow you to call anyone. They can have a telephone number – including local, long distance, mobile, and international numbers or not.

28. VoIP

29. How VoIP Works? Voice are converted into a digital signal by VoIP services that travel over the Internet. If regular phone number is called, the signal is converted to a regular telephone signal i.e. an analog signal before it reaches the destination. VoIP can allow you to make a call directly from a computer having a special VoIP phone, or a traditional phone connected to a special adapter .

30. VoIP Advantages and Disadvantages Advantages of VoIP: Some VoIP services offer features and services that are not available with a traditional phone, or are available but only for an additional fee. Paying for both a broadband connection and a traditional telephone line can be avoided. Disadvantages of VoIP: Some VoIP services don’t work during power outages and the service provider may not offer backup power. Not all VoIP services connect directly to emergency services through emergency service numbers .

31. Mobile IP Mobile IP  (or  MIP ) is an Internet Engineering Task Force (IETF) standard communications protocol that is designed to allow mobile device users to move from one network to another while maintaining a permanent IP address. Each mobile node is identified by its home address disregarding its current location in the Internet .