Mobile Computing - Mobile Network Architecture

Mobile Network Architecture

1. Mobile Network Architecture Prepared by: Dr. Osama Alshaki Lecture 2 10/13/2025 1

2. Introduction Mobile networks enable users to communicate wirelessly through radio signals. They consist of multiple components that work together to connect mobile devices to the internet or other users. Key elements: cells , base stations , and handover mechanisms . 10/13/2025 2

3. What is Mobile Network Architecture? It is the design and structure of how mobile communication systems operate. The architecture connects mobile users to the core network using radio cells managed by base stations. It ensures data, voice, and messages are transmitted efficiently. 10/13/2025 3

4. Components of Mobile Networks Mobile Station (MS): The user’s mobile device or smartphone. Base Station (BS): Connects mobile devices to the network via radio waves. Base Station Controller (BSC): Manages multiple base stations. Mobile Switching Center (MSC): Handles routing, call setup, and mobility. Core Network: Connects to external networks like the internet. 10/13/2025 4

5. Cellular Concept The total coverage area is divided into cells , each served by its own base station. Cells use different frequencies to reduce interference. This design allows frequency reuse , making the network more efficient. 10/13/2025 5

6. Why Use Cells? 10/13/2025 6 To increase system capacity: A llowing the system to handle more users at the same time without reducing the quality of service. To reduce radio interference: Minimizing signal overlap or noise between different users or base stations to improve communication quality. To reuse frequencies efficiently: U sing the same radio frequencies in different areas without causing interference, making better use of the available spectrum. To support mobility over large areas: A llowing users to move freely across wide regions while maintaining continuous connection (for example, during handover between cells).

7. Types of Cells Macro Cell: Covers large areas like highways or rural zones. Micro Cell: Used in urban areas for dense coverage. Pico Cell: Covers small indoor areas such as malls or offices. Femto Cell: Installed at homes or small businesses for better indoor signal. 10/13/2025 7

8. Base Station (BS) A base station acts as a bridge between the mobile device and the network. It handles radio transmission and reception , and manages communication within its cell. Every base station covers a specific geographical area . What is the BS Coverage? 10/13/2025 8

9. BS Coverage 10/13/2025 9 How far does the signal reach? It depends on the type of base station and the environment : Macro cell: up to 35 km in rural areas. Micro cell: around 200 m to 2 km in urban areas. Pico/ Femto cell: a few tens of meters (indoor). How many users can be served within that range? It depends on the network capacity and technology used (2G, 4G, 5G) : Macro cell: thousands of users. Micro cell: hundreds of users. Pico/ Femto cell: tens of users.

10. Base Station Controller (BSC) The BSC supervises several base stations. It manages: It usually exists in a centralized location (like a telecom operations center ) that manages many base stations in one region. Handover decisions between base stations. It ensures efficient use of network resources. 10/13/2025 10

11. Components of Mobile Networks 10/13/2025 11

12. Mobile Switching Center (MSC) The MSC is the central hub of mobile communication. It: Connects calls between mobile users. Manages user mobility. Interfaces with external networks such as traditional landline telephone system PSTN or the Internet. 10/13/2025 12

13. Core Network It is the “brain of the network” — it decides where your call or data should go and manages your connection everywhere. User authentication Billing and accounting Call routing and data management Mobility and session management 10/13/2025 13

14. How does a mobile phone call work? Your phone converts your voice to digital signals (using its microphone and encoder). These signals are sent as radio waves to the nearest base station (cell tower) . The base station doesn’t send it directly to the other phone. Instead, it sends the signal to the Mobile Switching Center (MSC) or core network . The MSC finds where the receiver’s phone is located (which base station it’s connected to). The MSC routes the call through the network — possibly through other switching centers or the internet (if VoLTE). The destination base station sends the signal to the receiver’s phone. The receiver’s phone decodes the digital signal back into sound using its speaker. 10/13/2025 14

15. Handover Concept When a user moves from one cell to another during an active call or data session, the connection must transfer smoothly. This automatic transfer of connection between base stations is called handover (handoff) . 10/13/2025 15

16. Why Handover is Needed Users are constantly moving while on calls or using data. Without handover, the connection would drop when leaving a cell. Handover ensures continuous communication and seamless user experience. 10/13/2025 16

17. Types of Handover Hard Handover (Break Before Make): The old connection is released before the new one is established. Soft Handover (Make Before Break): The new connection is established before the old one is released. 10/13/2025 17

18. Handover Process The mobile device monitors signal strength. The network detects when the current cell’s signal weakens. The system selects a nearby cell with a stronger signal. The connection is transferred to the new base station. 10/13/2025 18

19. Handover Challenges Rapid user movement (e.g., in cars or trains). Overlapping coverage between cells. Network congestion or high traffic load 10/13/2025 19

20. Handover in 4G/5G Networks Modern networks use advanced algorithms to ensure seamless handover . Higher Frequency Bands 5G uses millimeter waves ( mmWave ) — much higher frequencies (up to 100 GHz). Higher frequencies can carry more data at once → faster speeds. Wider Bandwidth 3G and 4G use channels of 5–20 MHz wide. 5G can use channels up to 100 MHz or even 400 MHz , meaning more data can flow simultaneously. 5G base stations use dozens or even hundreds of antennas . 10/13/2025 20

21. Thank You Q & A 10/13/2025 21