ppt for gsm sppu BE computer engineering

mobile computing

1. Unit III Global System for Mobile Communication (GSM)

2. GPRS - Protocol Stack Subnetwork Dependent Convergence Protocol (SNDCP) Logical Link Control (LLC) GPRS Tunneling Protocol (GTP) Base station subsystem GPRS Protocol (BSSGP) Radio Link Protocol (RLC) Medium Access Control (MAC)

3. The GPRS protocol stack for user data transmission Um (air interface), Gb, and Gn are the interfaces between MS and BSS, BSS and SGSN, and SGSN and GGSN respectively. SNDCP protocol encapsulates the IP packets in GPRS-specific packet formats. LLC layer provides a reliable logical link to the data units from the higher layer. This logical link is independent of the underlying radio interface protocols. LLC layer provides either acknowledged or unacknowledged data transmission. GTP tunnels user data between the two GSNs in the GPRS backbone network BSSGP layer conveys routing and QoS -related information between the BSS and the SGSN. RLC layer provides a reliable radio link for data transfer between the MS and the BSS. MAC layer controls the multiplexing of signaling and data messages from various GPRS users. GSM RF (Radio Frequency) layer controls the physical channel management, modulation, demodulation, transmission, power control, and channel coding/decoding.

4. GPRS - Data Routing Data routing or routing of data packets to and fro from a mobile user, is one of the pivot requisites in the GPRS network. The requirement can be divided into two areas: Data packet routing Mobility management.

5. Data Packet Routing The GGSN updates the location directory using routing information supplied by the SGSNs about the location of an MS It routes the external data network protocol packet encapsulated over the GPRS backbone to the SGSN currently serving the MS. It also decapsulates and forwards external data network packets to the appropriate data network and collects charging data forwarded to a charging gateway (CG). Important routing schemes: Mobile-originated message -  This path begins at the GPRS mobile device and ends at the host. Network-initiated message when the MS is in its home network -  This path begins at the host and ends at the GPRS mobile device. Network-initiated message when the MS roams to another GPRS network -  This path begins at the host of visited network and ends at the GPRS mobile device. The GPRS network encapsulates all data network protocols into its own encapsulation protocol called the GPRS tunnelling protocol (GTP). The GTP ensures security in the backbone network and simplifies the routing mechanism and the delivery of data over the GPRS network.

6. Mobility Management An MS can be in any of the following three states in the GPRS system. The three-state model is unique to packet radio. GSM uses a two-state model either idle or active. Active State Data is transmitted between an MS and the GPRS network only when the MS is in the active state. In the active state, the SGSN knows the cell location of the MS. Standby State In the standby state, only the routing area of the MS is known. (The routing area can consist of one or more cells within a GSM location area). When the SGSN sends a packet to an MS that is in the standby state, the MS must be paged. Because the SGSN knows the routing area of the MS, a packet paging message is sent to the routing area. On receiving the packet paging message, the MS relays its cell location to the SGSN to establish the active state. Idle State In the idle state, the MS does not have a logical GPRS context activated or any Packet-Switched Public Data Network (PSPDN) addresses allocated. In this state, the MS can receive only those multicast messages that can be received by any GPRS MS. Routing Updates When an MS that is in an active or a standby state moves from one routing area to another within the service area of one SGSN, it must perform a routing update. The routing area information in the SGSN is updated, and the success of the procedure is indicated in the response message.

7. GPRS Billing Techniques The SGSN and GGSN register all possible aspects of a GPRS user's behavior and generate billing information accordingly. This information is gathered in so-called Charging Data Records (CDR) and is delivered to a billing gateway. The GPRS service charging can be based on the following parameters: Volume -  The amount of bytes transferred, i.e., downloaded and uploaded. Duration -  The duration of a PDP context session. Time -  Date, time of day, and day of the week (enabling lower tariffs at off-peak hours). Final destination -  A subscriber could be charged for access to the specific network, such as through a proxy server. Location -  The current location of the subscriber. Quality of Service -  Pay more for higher network priority. SMS -  The SGSN will produce specific CDRs for SMS. Served IMSI/subscriber -  Different subscriber classes (different tariffs for frequent users, businesses, or private users). Reverse charging -  The receiving subscriber is not charged for the received data; instead, the sending party is charged. Free of charge -  Specified data to be free of charge. Flat rate -  A fixed monthly fee. Bearer service -  Charging based on different bearer services (for an operator who has several networks, such as GSM900 and GSM1800, and who wants to promote usage of one of the networks). Or, perhaps the bearer service would be good for areas where it would be cheaper for the operator to offer services from a wireless LAN rather than from the GSM network.

8. UMTS architecture

9. UMTS (Universal Mobile Telecommunications System) UMTS (Universal Mobile Telecommunications System) is a 3G mobile communication technology, part of the International Telecommunications Union's (ITU) IMT-2000 standard. UMTS improves data transfer speeds, enabling services like video calls, mobile internet, and multimedia. The UMTS architecture is divided into three main components: User Equipment (UE) UMTS Terrestrial Radio Access Network (UTRAN) Core Network (CN)

10. User Equipment (UE) The UE is the mobile device used by the end-user to access the network, which could be a mobile phone, tablet, or modem. Functions : Initiates communication with the network. Sends and receives data via the UTRAN. Comprises two parts: Mobile Equipment (ME) and a SIM card (specifically a UMTS Subscriber Identity Module, USIM). Example : A 3G smartphone used by a user to browse the internet or make a video call.

11. UMTS Terrestrial Radio Access Network (UTRAN) The UTRAN is responsible for establishing and managing the radio link between the User Equipment (UE) and the Core Network (CN). Components : Node B (Base Station) : Similar to base stations in 2G/4G networks, Node B handles communication with UE over the air interface (WCDMA). Responsible for radio signal transmission and reception, power control, and channel coding. Radio Network Controller (RNC) : Controls multiple Node Bs. Manages handovers between different Node Bs. Controls resources, mobility management, and quality of service (QoS). Example : A 3G cellular tower (Node B) communicates with multiple smartphones in its coverage area, while the RNC manages the tower and coordinates with other towers for seamless handovers as a user moves.

12. Core Network (CN) The core network handles user authentication, mobility management, call/session establishment, and routing data to external networks such as the Internet or public-switched telephone networks (PSTN). Core Network is divided into two domains : Circuit-Switched Domain (CS) : Handles traditional voice calls and SMS. Components include the Mobile Switching Center (MSC) and Gateway MSC (GMSC) , which connect UMTS to PSTN for voice services. Packet-Switched Domain (PS) : Handles data services such as internet browsing, email, video streaming, etc. Components include Serving GPRS Support Node (SGSN) and Gateway GPRS Support Node (GGSN) . These nodes are responsible for data packet handling, mobility management, and routing packets between the UE and external packet data networks (e.g., the internet). Example : When a user initiates a video call (combining both voice and data), the core network's circuit-switched domain manages the voice traffic, while the packet-switched domain handles the video data.

13. UMTS Architecture in Action: Example Mobile User Initiates a Video Call : The user opens a video call app on a 3G smartphone (User Equipment). UTRAN Handles Communication : The smartphone communicates with the nearest Node B (base station) over the WCDMA air interface. The Node B converts radio signals into data and transmits them to the Radio Network Controller (RNC). The RNC manages resources for the video call, ensuring quality of service, and, if the user moves, manages the handover to another Node B without dropping the connection. Core Network Manages the Call : The Circuit-Switched (CS) domain handles voice data, routing it to the Mobile Switching Center (MSC), which may connect it to a Gateway MSC (GMSC) if the call is made to a user on a different network (e.g., PSTN). The Packet-Switched (PS) domain handles video and other data traffic, routing it via the SGSN and GGSN to an external IP network (e.g., the internet). Handover and Continuity : As the user moves, the RNC seamlessly hands over control of the connection from one Node B to another, ensuring uninterrupted communication.

14. Key Features of UMTS: WCDMA (Wideband Code Division Multiple Access) is used as the air interface, which allows multiple users to share the same frequency band by assigning unique codes to each user. Seamless Handover : Users can move between different base stations without interruption in voice calls or data connections. High Data Speeds : UMTS offers faster data rates compared to 2G, allowing for services like mobile internet, video calling, and multimedia streaming. UMTS architecture is the foundation of 3G networks, providing enhanced connectivity and services compared to its 2G predecessors, paving the way for the high-speed data requirements of modern mobile applications.

15. Applications of UMTS Streaming / Download (Video, Audio) Videoconferences. Fast Internet / Intranet. Mobile E-Commerce (M-Commerce) Remote Login Background Class applications Multimedia-Messaging, E-Mail FTP Access Mobile Entertainment (Games)

16. UTRAN ( Universal Terrestrial Radio Access Network)

17. UTRAN (Universal Terrestrial Radio Access Network) is the access network component of the UMTS (Universal Mobile Telecommunications System) , responsible for wireless communication between User Equipment (UE) (like smartphones or modems) and the Core Network (CN) in a 3G system. It plays a crucial role in managing radio resources, enabling mobile communication, and handling both voice and data traffic. The UTRAN architecture consists of two key components: Node B (Base Stations) Radio Network Controller (RNC) Together, these elements manage the interaction between the mobile device and the core network, handling everything from radio signal transmission to mobility and resource management.

18. Components of UTRAN Node B (Base Station) Node B is similar to a base station in 2G networks. It handles the physical layer tasks such as radio transmission and reception, modulation, demodulation, power control, and channel coding. Function : Communicates with User Equipment (UE) over the air interface (WCDMA in UMTS). Handles lower-layer processing, like encoding/decoding of signals. Manages the air interface, including power control and transmission/reception of data packets. Connects to the Radio Network Controller (RNC) , which controls multiple Node Bs. Example: A cellular tower in a 3G network communicates with nearby smartphones, sending and receiving voice calls, texts, and data (such as internet browsing).

19. 2. Radio Network Controller (RNC) The RNC is the key control element within UTRAN, responsible for managing multiple Node Bs. It handles higher-layer functions such as resource management, mobility, and quality of service (QoS). Function : Radio Resource Management : Allocates resources to ensure efficient use of radio frequencies. Mobility Management : Ensures that users can move between different cells (Node Bs) without dropping the connection, handling handovers. Handover Control : Manages both intra-RNC handovers (between Node Bs controlled by the same RNC) and inter-RNC handovers (between Node Bs controlled by different RNCs). Ciphering : Performs encryption and decryption of user data for security. Soft Handover Support : In UMTS, a UE can connect to multiple Node Bs simultaneously for better signal quality. Example : The RNC is located in a central facility, managing several cellular towers across a city. When a user moves from one cell to another, the RNC ensures that the call or data session is handed over seamlessly to the next Node B.

20. Air Interface and Protocol Stack UTRAN uses WCDMA (Wideband Code Division Multiple Access) as the air interface protocol, which enables multiple users to share the same frequency by assigning a unique code to each user. The UTRAN manages the radio interface protocols, including: Radio Resource Control (RRC) : Handles the establishment, maintenance, and release of radio connections. Radio Link Control (RLC) : Ensures data is transferred reliably. Medium Access Control (MAC) : Manages data transfer between the physical layer and higher layers.

21. Key Features of UTRAN Soft Handover : Unlike traditional hard handovers (where a user’s connection is dropped and re-established), UMTS supports soft handovers, allowing the UE to connect to multiple Node Bs at the same time. This improves connection reliability and signal quality, especially at cell edges. High Data Speeds : UTRAN allows for higher data rates (up to 2 Mbps) compared to 2G networks, enabling data-heavy services like video calling, mobile internet, and multimedia streaming. Seamless Mobility : UTRAN ensures that users can move freely between different areas covered by different Node Bs, with no interruption in service. Radio Resource Management : Efficient allocation of radio spectrum ensures optimal use of available bandwidth, even during high traffic periods.

22.   There are four interfaces connecting the UTRAN internally or externally to other functional entities: lu : lu interface is an external interface that connects the RNC to the Core Network . Uu : Uu is also external, connecting the Node B with the User Equipment. lub : lub is an internal interface connecting the RNC with the Node B. lur :  lur interface which is an internal interface most of the time, but can, exceptionally be an external interface too for some network architectures. The Iur connects two RNCs with each other.

23. WIRELESS LAN A wireless LAN or WLAN is the linking of more devices without the use of wires. WLAN utilizes the modulation technology based on radio waves to communicate between devices in a limited network area. It gives users the mobility to move around within a broad coverage area & still be connected to the network. Implemented as an extension to wired LAN within a building

24. WIRELESS LAN Advantages Mobility Low implementation cost Installation speed and simplicity Network expansion Reduced cost of ownership Higher user to install base ratio Reliability Scalability

25. Wireless LAN applications Office/ campus environment Factory shop floor Workgroup environment Homes Heritage buildings War/defence sites

26. WLAN Standards Several WLAN standards: IEEE 802.11b offering 11 Mbit/s at 2.4 GHz The same radio spectrum is used by Bluetooth. A short-range technology to set-up wireless personal area networks with gross data rates less than 1 Mbit/s IEEE 802.11a , operating at 5 GHz and offering gross data rates of 54 Mbit/s IEEE 802.11g offering up to 54 Mbit/s at 2.4 GHz. IEEE 802.11n upcoming standard up to 300 Mbit/s (two spatial streams; 600 Mbit/s with 4 spatial streams)

27. 802.11 – System Architecture

28. 802.11 IEEE 802.11 is a set of standards that define how to implement wireless local area network (WLAN) communication. The Institute of Electrical and Electronics Engineers (IEEE) developed these standards, part of the IEEE 802 family of standards for local and metropolitan area networks.

29. What is the 802.11 family? 802.11 (1997)  is now outdated. Legacy technology specified two spread-spectrum methods in the 2.4 GHz band:  frequency hopping  and direct sequence, each at 1 Mbps or 2 Mbps, along with diffuse infrared at 1 Mbps. 802.11b (1999)  boosted speed to 11 Mbps using direct sequence spread spectrum (DSSS) in 2.4 GHz. It also accommodated weak signals by maintaining lower DSSS modes and emerged as the signature WLAN technology. 802.11a (1999)  used an OFDM physical layer in the 5 GHz band to transmit up to 54 Mbps. The advantage of 5 GHz is it's less crowded, but the higher frequency can limit its effective signal range. 802.11g (2003)  used OFDM in the 2.4 GHz band to achieve a similar 54 Mbps transmission, excluding forward error correction . However, this approach also is subject to signal interference from nearby devices. 802.11g and 802.11b equipment are compatible, and vendor equipment carries both designations.

30. 802.11n (2009) , also called Wi-Fi 4, marked the start of new Wi-Fi standards branding. All 802.11n wireless products support multiple input, multiple output ( MIMO ) technology, in which multiple transmitters and receivers are used to transfer more data at the same time. The addition of multiple antennas boosts the theoretical data rate to 450 Mbps in 2.4 GHz operation. 802.11n reportedly is backward-compatible with 802.11a, 11b and 11g networks. 802.11ac (2013) , also known as Wi-Fi 5, pivots off amendments to 802.11n. Maximum data rates reach the gigabyte level in 5 GHz operation, with expanded channel width, twice the number of spatial streams, 256 QAM bandwidth increases and enhanced multiuser MIMO. 802.11af (2014)  enables WLAN operation in very high frequency and ultra high frequency bands normally reserved for TV broadcast signals. 802.11ah (2017)  describes WLANs with low power consumption that could power extended-range hotspots or serve to handle traffic overloads on a cellular network. 802.11ah-enabled WLANs can provide an alternative to short-range  Bluetooth  connectivity. 802.11aj (2018) , also called the Chinese Millimeter Wave frequency band, is for WLANs in China and other regions. It provides backward compatibility with 802.11ad, which is in review. 802.11ax (2019) , also known as Wi-Fi 6, is the current standard. It uses the 2.4 GHz and 5 GHz frequency bands but has the option to use 6 GHz.

31. Advantages of IEEE 802.11 Architecture Fault Tolerance:  The centralized architecture minimizes the bottlenecks and introduces resilience in the WLAN equipment. Flexible Architecture : Supports both temporary smaller networks and larger, more permanent ones. Prolonged Battery Life:  Efficient power-saving protocols extend mobile device battery life without compromising network connections.

32. Disadvantages of IEEE 802.11 Architecture Noisy Channels:  Due to reliance on radio waves, signals may experience interference from nearby devices. Greater Bandwidth and Complexity:  Due to necessary data encryption and susceptibility to errors, WLANs need more bandwidth than their wired counterparts. Speed:  Generally, WLANs offer slower speeds compared to wired LANs.

33. Applications of IEEE 802.11 Architecture Home   Networking:  Connecting devices, laptops, smart TVs, speakers, gaming consoles etc. Wi-Fi Hotspots:  Free or paid internet access to visitors in coffee shops, hotels, airports, malls and restaurants. Connectivity in Campus:  Provide internet access in university, colleges, schools or corporate campuses.

34. Compare various IEEE 802.11 X standards.

35. Standard Year Frequency Max Data Rate Channel Width Range Key Features 802.11 1997 2.4 GHz 2 Mbps 20 MHz ~20 meters indoors First Wi-Fi standard, very slow, no longer used. 802.11a 1999 5 GHz 54 Mbps 20 MHz ~35 meters indoors Higher speed, shorter range, less interference. 802.11b 1999 2.4 GHz 11 Mbps 20 MHz ~40 meters indoors Cheaper than 802.11a but with more interference. 802.11g 2003 2.4 GHz 54 Mbps 20 MHz ~38 meters indoors Backward compatible with 802.11b, more widespread. 802.11n 2009 2.4 / 5 GHz 600 Mbps (theoretical max) 20/40 MHz ~70 meters indoors MIMO (Multiple Input, Multiple Output) for higher speeds and better range. 802.11ac 2013 5 GHz 1.3 Gbps (theoretical max) 20/40/80/160 MHz ~35 meters indoors Introduced MU-MIMO (Multi-User MIMO), wider channels. 802.11ad 2012 60 GHz 6.7 Gbps 2160 MHz ~10 meters indoors Extremely high speeds for short-range communications. 802.11af 2014 TV White Spaces 568 Mbps 6-8 MHz ~1 km outdoors Longer range, used TV spectrum, also called “White-Fi.” 802.11ax (Wi-Fi 6) 2019 2.4 / 5 GHz 9.6 Gbps 20/40/80/160 MHz ~50 meters indoors OFDMA (Orthogonal Frequency Division Multiple Access), better efficiency in dense environments. 802.11ay 2021 60 GHz 20 Gbps 2.16 GHz ~300 meters indoors Very high speed, used for short-distance communications like virtual reality. 802.11be (Wi-Fi 7) Expected 2024 2.4 / 5 / 6 GHz 46 Gbps Up to 320 MHz TBD Ultra-low latency, higher speeds, more spectrum efficiency.

36. Explain different architectures of WLAN.

37. Independent Basic Service Set (IBSS) or Ad Hoc Mode: In this architecture, devices (also called stations) communicate directly with each other without any central authority like an access point. This forms a peer-to-peer network where each station directly communicates with others in its range. Ad hoc networks are temporary and often used in small, closed environments like a meeting room, where quick communication between devices is necessary without external network infrastructure. Advantages : Simple to set up with no requirement for access points. Ideal for small, temporary networks like file sharing, and direct device communication. Disadvantages : Limited range and scalability (depends on the number of devices). No central authority means security and management are decentralized, leading to potential issues. Ideal for small group meetings, and device-to-device communication in a local area without the need for long-term infrastructure.

38. Basic Service Set (BSS) or Infrastructure Mode: In BSS architecture, a central Access Point (AP) connects wireless devices to a wired network or other wireless devices. The access point provides a connection to a wired network backbone or to other wireless devices in the network, facilitating centralized communication. All communication between devices goes through the access point, even if two devices are within range of each other. BSS can also provide access to the internet or other external networks. Advantages : Centralized management and control over the network. Better scalability than ad hoc networks. Access to wired networks and the internet is easier to manage. Disadvantages : If the AP fails, the devices cannot communicate with each other or the network. Range is limited to the coverage area of the AP. Home networks, small office networks, and where a single point of access is enough for the number of devices.

39. Extended Service Set (ESS): ESS is a collection of multiple Basic Service Sets (BSS), connected through a wired Distribution System (DS), usually Ethernet, to provide greater wireless coverage. Multiple access points are distributed across a larger geographical area, and devices can move between access points without losing connection due to seamless handoffs between the APs. Roaming is enabled as the devices can switch between access points based on signal strength. Diagram : Advantages : Provides larger coverage compared to a single BSS. Seamless roaming allows devices to maintain connectivity while moving across different areas. Can support a large number of devices and scalable to enterprise needs. Disadvantages : Requires careful planning to avoid interference between overlapping access points. More complex to set up and manage compared to a single BSS. Used in enterprises, university campuses, large offices, and multi-story buildings where a single access point cannot cover the whole area.

40. Mesh Network In a mesh network architecture, multiple access points (or nodes) communicate directly with one another to form a network that doesn't rely on a wired backbone for communication between APs. The nodes relay data for the network, creating multiple paths for the data to travel. This allows for greater redundancy and coverage because the data can take several paths to its destination. A failure in one node won't cause the network to fail, as the data will reroute through another node. Advantages : Redundancy: If one access point fails, the data is rerouted through others. Easier to expand by adding more nodes without major reconfiguration. Suitable for large areas without a reliable wired backbone. Disadvantages : More complex setup and management than traditional infrastructure. Performance can degrade as the number of hops between nodes increases (higher latency). Ideal for large outdoor areas, industrial sites, military applications, or areas where running wired infrastructure is costly or impossible, such as large campuses or rural settings.

41. Each of these WLAN architectures is suited to different network environments: IBSS/Ad Hoc Mode : Ideal for temporary, peer-to-peer communication. BSS/Infrastructure Mode : The most common WLAN architecture, ideal for home and small business networks. ESS : Used in large, structured networks that require seamless mobility and coverage over large areas. Mesh Networks : Great for outdoor or large indoor spaces where redundancy and range without a wired backbone are crucial.

42. Unit IV GSM Networking Signaling and Mobile Management

43. Content GSM MAP Service framework, MAP protocol machine, GSM location management, Transaction management, Mobile database, Introduction to location management HLR and VLR, VLR and HLR Failure restoration, VLR identification algorithm, O-I, O-II algorithm etc. Overview of handoff process; Factors affecting handoffs and performance evaluation metrics; Handoff strategies; Different types of handoffs (soft, hard, horizontal, vertical).