Cellular Networks
- Cellular networks enable mobile phone communication by dividing land into cells,
each served by an antenna.
- Cells provide coverage using multiple frequencies, forming the backbone of cellular networks.
- Supports both voice and data communication, with user control over
functionality (e.g., enabling/disabling cellular data or using airplane mode).
- Key generations of cellular technology:
- 3G (1998): Enabled larger data transfers, supporting GPS, mobile TV, video
conferencing, and video on demand.
- 4G/LTE: Based on GSM (Global System for Mobile
Communications), offering speeds up to 150 Mbps; LTE
Advanced (LTE-A) increased speeds to 300 Mbps.
- 5G (2020): Supports up to 10 Gbps on high frequencies and
100–900 Mbps on lower frequencies, enabling advanced applications like
Internet of Things (IoT) and cloud processing.
Wi-Fi and 802.11 Networks
- High-speed 802.11 wireless networks provide connectivity at home and in offices
without wired connections.
- Limited range; devices connect to a local access point for network access.
- Supports voice, video, and data transfer, including voice calls over Wi-Fi when
cellular signal is weak.
- Mobile phones can function as hotspots, sharing cellular data (e.g., 5G) with other
devices via Wi-Fi.
- Requires carrier support; may incur additional charges.
Subscriber Identity Module (SIM)
- SIM cards store carrier and subscriber information, including:
- Carrier details and network configuration.
- SIM ID and associated phone number.
- Storage for contacts and messages (transferable between devices).
- eSIM (Embedded SIM): A software-based SIM integrated into the device, transferable
via QR code or software settings.
- Eliminates the need for physical SIM cards; supports multiple profiles on a single device.
Bluetooth Connectivity
- Used to pair devices like headsets or speakers with mobile phones.
- Pairing process ensures security and automatic reconnection:
- Enable Bluetooth on both devices and set them to discoverable mode.
- Select the device on the mobile phone and confirm a PIN (static or
dynamic).
- Once paired, devices reconnect automatically without re-pairing.
- Refer to device documentation for specific pairing instructions.
Global Positioning System (GPS)
- GPS: Developed by the U.S. Department of Defense, uses satellites to determine
location (longitude, latitude, altitude).
- Requires visibility of at least four satellites for accurate readings.
- Alternative location methods:
- Wi-Fi triangulation: Uses nearby networks to estimate location when GPS is
unavailable.
- Cellular tower triangulation: Determines location based on signal strength
from multiple towers.