Solution

The correct answer is A - III, B - IV, C - I, D - II

Key Points

• A. CDMA:
  • CDMA or Code-Division Multiple Access is a digital cellular technology that uses spread spectrum techniques.
  • The unique attribute that separates it from other technologies is its ability to allow several transmitters to send information simultaneously on a single communication channel.
  • This is accomplished by assigning a code to every transmitter, consequently enabling multiple access, hence the term in its name "Multiple Access".
• B. GSM:
  • GSM is an abbreviation for Global System for Mobile communications (originally from Groupe Spécial Mobile).
  • It is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation digital cellular networks used by mobile devices such as mobile phones and tablets. It's a cellular technology that employs a combination of two major multiple access schemes, FDMA (Frequency Division Multiple Access) and TDMA (Time Division Multiple Access).
  • In FDMA, each user is allocated a unique frequency band or channel while TDMA allows several users to share the same frequency band by dividing it into different time slots.
• C. UMTS:
  • UMTS which stands for Universal Mobile Telecommunications System, is a third-generation (3G) mobile cellular technology for networks based on the GSM standard.
  • With advancements from previous technologies, UMTS is capable of providing higher data transfer rates and thus can contribute to a richer and more diverse range of services.
  • It is known for offering a consistent set of services to mobile computer and phone users, irrespective of the fact that people are on the move.
• D. WiFi:
  • WiFi is a technology that allows an electronic device to exchange data or connect to the internet wirelessly using radio waves.
  • It provides the underlying technology to create a home or business network (LAN) without physical wires or cables that is, a wireless network.
  • On this network, users connect their devices to access the internet, share files, play games and many other things.
  • This is convenient for devices like laptops, tablets, and smartphones that may frequently move throughout the space.