Social Networks, Web 2.0, Telecoms, and Mobile Technology
Social Networks and Web 2.0
A social network is a community of people related by some kind of interest, affinity, or anything else they have in common.
Web 2.0 is a set of sites where the user is not a mere recipient of content but participates in its development and diffusion.
Telecommunications Fundamentals
Telecoms: Media broadcasting, transmitting, and receiving messages using electrical or electromagnetic signals.
Components of a telecommunication system: Transmitter, transmission channel, and receiver.
Channel Capacity: Indicates the speed at which data can be transmitted by that channel, in bits per second.
Bandwidth: Indicates the maximum amount of data that can pass through the channel in a determined time, usually 1 second.
Signal Disruption: Causes a loss of signal quality. It is caused by noise, attenuation, and distortion.
Multiplexing and Optical Fiber
Multiplexing: A technique that allows simultaneous transmission of multiple signals over a single channel.
Optical Fiber:
- Advantages: Smaller size and weight than coaxial cables and twisted pair; allows greater bandwidth; immune to noise and electrical interference; less signal attenuation.
- Disadvantages: High price.
- Applications: Long-distance communication networks, multiple communications, high-speed internet, or local area networks.
Modulation
Differences between Modulating Signal and Carrier Signal:
- The modulating signal is a low-frequency signal containing the information to be transmitted.
- The carrier signal is a high-frequency signal that is modified taking into account the information of the modulating signal.
Mobile Telephony
Operation of Mobile Terrestrial: The coverage area of each base station is called a cell. Although each cell is assigned a frequency range, it can be used by two or more cells provided these are not adjacent. Each cell has to overlap with its neighbors, so that as a user moves through the network, the call is transferred from one cell to another without cutting the communication.
Generations of Mobile Telephony
- 1st Generation: Appeared in 1979; analog systems, bulky terminals, offered little coverage, and only transmitted voice.
- 2nd Generation: Appeared in 1990; digital systems, terminals with lower size and wider coverage; allowed transmission of voice, sending data at very small speeds, and SMS messaging systems.
- 3rd Generation: Can provide worldwide coverage with great speed, internet access, and transmission of voice, data, images, videos, etc.
Satellite Communications
Satellite Communications: Radio repeaters located in space, receiving radio signals transmitted from the ground, amplifying them, and transmitting them back to the surface. They have the advantage of covering large areas and the disadvantage of interference and signal weakening.
GPS
GPS: Used to determine position, the best route between two points, tracking objects, people, or animals in motion, mapping, etc.
Communication Networks
Types of Communication Networks According to Geographical Extent:
- Local Area Networks (LAN)
- Wide Area Networks (WAN)
Types of Communication Networks According to Computer Disposition:
- Star Network
- Bus Network
- Ring Network
Internet Operation
Information Transmission via Internet: This is done according to the packet communication method, which involves dividing the message into parts or packets. The message is split into separate packages that are sent to routers, which are responsible for seeking the optimal way to reach their destination.
TCP/IP, DNS, and ADSL
- TCP: The TCP protocol is responsible for dividing the information into packets, numbering them so they can be joined in the correct order at the target, adding additional information for decoding the message, and detecting possible transmission errors.
- IP: The IP protocol adds to each packet the IP addresses of the recipient and sender. An IP address is a code that identifies each computer as part of the internet. It consists of 4 numbers less than 255, separated by dots.
- DNS: The Domain Name System is used for simplicity to recall, write, and manage the complicated IP addresses.
- ADSL: Asymmetric Digital Subscriber Line. Based on the copper pair from the normal telephone line, high speed that can transmit both voice and data through it, using an ADSL modem. The line is divided into 3 channels: two for receiving and sending data and one for voice communication.