Wireless Communications

Evolution of Wireless Communication Systems

Evolution of Wireless Communication Systems

Evolution of Wireless Communication Systems, Evolution of Wireless Communication Systems Viva Questions, Short Questions on Evolution of Wireless Communication Systems, Wireless Communications Viva Questions,

Short-Answer Type Questions with Answers

Q.1. List and describe the three types of data flow in wireless communication.


Simplex – When data moves from the transmitter to the receiver only. The receiver cannot reply.

Half-duplex – When data can move in both directions but not simultaneously. When one is transmitting, the other must listen until the transmission is finished.

Full-duplex – Data can move in both directions simultaneously.

Q.2. Discuss the advantages and disadvantages of standards.

Ans. Standards ensure that devices interoperate with those from other vendors, and create competition.

Other advantages are

  • Lower prices not only for consumers but also lower manufacturing costs
  • No large research investments
  • Standards also help protect consumer investment in technology by creating a migration path

The disadvantages are

  • International standards can be a threat to industries in large countries since they benefit manufacturers in small countries and allow them to make and sell their products to the originating country, often at a much lower cost.
  • Some countries create their own standards instead of adopting an international one which often forces manufacturers to build more expensive equipment that complies with multiple standards and the consumer ultimately pays the higher price.

Q.3. What are the main benefits of IEEE 802.11e WLAN standards?

Ans. IEEE 802.11e adds QoS capabilities and enhances the MAC protocol. It also permits 802.11 WLANs to prioritize voice and video traffic.

Q.4. What are some advantages and disadvantages of IEEE 802.11a WLANs?

Ans. IEEE 802.11a WLANs are faster than IEEE 802.11b and g. They operate on a 5-GHz band and are not subject to interference from cordless phones, microwaves, or Bluetooth. The disadvantages are that they are not backward compatible with 802.11b, provide a shorter range than 802.11b, and also do not support QoS.

Q.5. What is authentication? What is the disadvantage of the authentication included in the

IEEE 802.11 standards and what kind of authentication should be considered for WLANs?

Ans. Authentication is the process of establishing whether a user is authorized to communicate on the network. IEEE 802.11 standard authenticates the device only, but not the user. RADIUS authentication should be considered to increase the security of WLANs.

Q.6. List the three major ways in which satellites are used. Which one is used for fixed broadband wireless?

Ans. Satellites are used in scientific and environmental research, weather forecast, military applications, and as reflectors. Satellites as reflectors are used for fixed broadband wireless purposes.

Q.7. List some potential applications for RFID technology.

Ans. The applications include people location within a building, parking-lot access cards, laboratory experiment tracking, timber-grade monitoring, permanent identification of valuable items such as art, and security-guard monitoring (rounds monitoring), among many other applications.

Q.8. List three specific challenges associated with RFID system implementation.

Ans. Increased network traffic, increased storage requirement, network availability, and security are some specific challenges associated with RFID system implementation.

Q.9. Which methods can be used to temporarily or permanently disable the RFID tag?

Ans. Physical destruction, the kill command, locking, and blocker tags are some of the methods which can be used to temporarily or permanently disable the RFID tag.

Q.10. What is a wireless access service provider (WASP)? What type of services are provided by a WASP?

Ans. A WASP can design and create a wireless application and even deliver the hardware, software, security, and networks as one complete package. Because many of the wireless devices, languages, and applications are so new and diverse, a WASP may have the expertise needed to get the project up and running quickly.

Many WASPs may even host the application on their own wireless network, in which case the services are subscribed to, rather than being purchased.

Q.11. List some issues that can be answered by performing a wireless site survey prior to making a decision on WLAN implementation.

Ans. Issues such as location of a wireless access point and antennas, throughput required, type of client adapters, power requirements, expansion of the wireless network and impact on current design, security features and policies required, number of radio channels required, radio signal range can be resolved.

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