Wireless Communication — Part 1 MCQs with Explanations

Wireless Communication Definition: Wireless communication is the transfer of information between two or more points that are not physically connected by an electrical conductor or cable. Explanation of Correct Option (B): Option B, "Sending data from one location to another without the use of a physical medium," is the correct definition of wireless communication. This accurately describes how wireless systems operate, using electromagnetic waves (like radio waves, microwaves, infrared, etc.) to transmit data through the air or space. Why other options are incorrect: Option A: This describes wired communication, where a physical medium (like a cable or fiber optic) is necessary to transmit the data. Option C: The term "virtual medium" isn't a standard term in the context of communication. While concepts like virtual networks exist, they still rely on underlying physical infrastructure for data transmission. Therefore, this option is incorrect and unclear. Option D: Since option B accurately defines wireless communication, option D is incorrect.

Wireless Communication: A method of communication where information is transmitted between two or more points without using physical conductors such as wires or cables. This is achieved using electromagnetic waves. Why is Wireless Communication Used? The correct answer is D: All of the mentioned . Let's examine why each option contributes to the widespread use of wireless communication: Option A: It enables billions of people to connect to the Internet This is a major driving force behind the adoption of wireless communication. The ease and mobility offered by wireless technologies like Wi-Fi, cellular networks (3G, 4G, 5G), and satellite communication have made internet access readily available to a vast global population. Without wireless, internet access would be severely limited, confined largely to locations with wired infrastructure. Option B: Lowers the cost of network infrastructure Installing and maintaining a wired network infrastructure is expensive. It requires extensive cabling, trenching, and potentially building new infrastructure to reach remote areas. Wireless technologies significantly reduce these costs, especially in scenarios requiring wide area coverage or reaching difficult-to-wire locations. The cost savings are substantial, making communication accessible in areas where a wired network would be economically infeasible. Option C: Makes services more inexpensive The reduced infrastructure costs associated with wireless technologies translate directly into lower service costs for consumers. Competition among wireless providers also drives down prices, making communication services more affordable and accessible to a wider range of users. Wireless service providers often offer various plans and bundles to cater to different needs and budgets.

Wireless Communication: Wireless communication is the transfer of information over a distance without the use of wires or cables. It relies on various electromagnetic waves to transmit data. LAN (Local Area Network): A LAN is a network that connects devices within a limited geographical area, such as a home, office, or school. LANs can be wired (using Ethernet cables) or wireless (using Wi-Fi). WAN (Wide Area Network): A WAN is a network that connects devices over a large geographical area, such as a city, country, or even globally. WANs typically use a combination of wired and wireless technologies. Examples include the internet. PAN (Personal Area Network): A PAN is a network that connects devices within a very small area, typically around a person. PANs are often wireless, using technologies like Bluetooth or near-field communication (NFC). Correct Answer: Option D - All of the mentioned While LANs and WANs can utilize wired connections, they also commonly incorporate wireless technologies (Wi-Fi for LANs and various wireless technologies for WANs). PANs are almost exclusively wireless. Therefore, all three (LAN, WAN, and PAN) can be considered types of wireless communication in certain configurations.

Wireless Communication: Wireless communication is the transfer of information over a distance without the use of wires or physical conductors. It relies on electromagnetic waves to transmit signals. Explanation: The question asks which option is NOT an example of wireless communication. Option A: Wi-Fi: Wi-Fi is a popular wireless networking technology that uses radio waves to connect devices to a network. This is a clear example of wireless communication. Option B: Mobiles: Mobile phones (cell phones) use radio waves to communicate with cell towers, enabling voice calls and data transmission. This is also a prime example of wireless communication. Option C: Landline: A landline telephone system uses physical wires (copper cables) to transmit voice signals. This is fundamentally different from wireless communication, as it relies on a physical connection between the phone and the network. Option D: Wireless Computer Parts: This refers to components like wireless keyboards, mice, and headsets that use radio frequencies or Bluetooth to communicate with a computer. This is wireless communication. Correct Answer: Therefore, the correct answer is Option C: Landline , as it utilizes wired communication and not wireless technology.

Mobile communication is a wireless communication system that allows users to communicate over a distance using portable devices. The key characteristic is the mobility of the communication devices. This means the devices can move around while maintaining a connection. Let's analyze the options: Option A: Allows to communicate from different locations without the use of physical medium This is the correct answer . Mobile communication inherently relies on wireless transmission, meaning no physical wires or cables connect the communicating devices. The signal travels through the air (or other mediums like satellite) to reach its destination. Option B: Allows to communicate from different locations with the use of physical medium This is incorrect. If a physical medium is used, it's not considered mobile communication in the true sense. Think of a wired telephone network – it allows communication between different locations but requires physical cables. Option C: Allows to communicate from same locations without the use of physical medium While this might describe some wireless local area networks (WLANs), it doesn't capture the essence of *mobile* communication. The emphasis is on the ability to communicate while *moving* between locations. Option D: Allows to communicate from same locations with the use of physical medium This describes a wired local communication scenario, not mobile communication.

Explanation: First, let's define some key terms: Air Interface: The air interface refers to the radio frequency (RF) link between a mobile device (like a cell phone) and a base station (cell tower) in a wireless communication system. It defines how data is transmitted and received over the airwaves. Modulation: This is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a message signal such that the message signal is contained within the variations of the carrier. It's how information is encoded onto the radio waves. Coding Scheme: This refers to the techniques used to add redundancy to the data for error correction and detection during transmission. It helps improve the reliability of the communication even in the presence of noise or interference. Correct Answer: A: Modulation and coding schemes EDGE (Enhanced Data rates for GSM Evolution) uses various combinations of modulation and coding schemes to achieve different data rates and robustness levels. The air interface is defined entirely by these schemes. The choice of modulation and coding scheme directly impacts the spectral efficiency (how much data can be transmitted in a given bandwidth) and the robustness of the communication (its ability to withstand interference). Different schemes offer different trade-offs between speed and reliability. Why other options are incorrect: B: Coding schemes: While coding schemes are a crucial part of the EDGE air interface, they are only one aspect. The modulation method is equally important and forms a complete definition of the air interface with coding. C: Modulating air interface: This is not a standard term. The air interface is characterized by a combination of modulation and coding, not just modulation alone. D: Air interface coding schemes: Similar to option B, this is too narrow. The complete definition requires both modulation and coding schemes.

A cordless telephone system uses radio waves for communication between the handset and the base station. The range of these radio waves is limited. Cordless telephones use short-range radio frequencies to communicate. This means there's a limited distance the handset can be from the base station before the signal becomes too weak to work effectively. Option A: Within a home . Cordless phones are designed to work within a typical home. The range is usually sufficient to cover a house. Option B: Within a building . Similar to a home, a cordless phone *could* work within a building, depending on the building size and construction materials which may interfere with the signal. Larger buildings or those with significant interference could cause problems. Option C: Within campus . A campus is a significantly larger area than a home or building. The range of a cordless phone is not designed for such distances, and significant signal degradation and interference are highly likely. Option D: Within a city . A city is even larger than a campus. The distance and interference from various sources (other wireless devices, buildings, etc.) would make a cordless phone completely impractical and unusable. Therefore, the correct answer is Option D: Within a city , because the range of a cordless phone is far too limited for such a large and interference-prone environment.

Question: 2G CDMA standard, IS-95, was proposed by which company? Definitions: 2G (Second Generation) Wireless Technology: Represents the second generation of cellular network technology. It marked a significant improvement over 1G (analog) systems by introducing digital transmission, leading to improved voice quality, increased capacity, and enhanced security. CDMA (Code Division Multiple Access): A channel access method used by radio communication systems. Unlike other multiple access schemes like TDMA (Time Division Multiple Access) or FDMA (Frequency Division Multiple Access), CDMA allows multiple users to share the same frequency band simultaneously by using different codes to distinguish between them. This is achieved by spreading the signal across a wider bandwidth using a unique code for each user. IS-95: A specific standard for CDMA-based 2G cellular networks. It defines the air interface specifications (how the mobile phone communicates with the base station) for the system. Correct Answer: B: Qualcomm Qualcomm played a pivotal role in the development and standardization of IS-95, the prominent CDMA standard for 2G networks. They were instrumental in developing the underlying CDMA technology and were heavily involved in its commercialization. Why other options are incorrect: A: Nippon Telephone and Telegraph (NTT): While NTT is a major telecommunications company, it wasn't the primary proponent of the IS-95 standard. Their contributions to 2G and beyond were significant in their own right, but not specifically focused on IS-95 development. C: Bellcore and Motorola: Both Bellcore (now Telcordia Technologies) and Motorola contributed to the advancement of cellular technology, but they weren't the principal developers behind the IS-95 CDMA standard. They had their own involvement in other cellular technologies and standards. D: AT&T Bell Laboratories: AT&T Bell Labs also played a significant role in the evolution of telecommunications, including contributions to early cellular systems. However, the core development and proposal of the IS-95 standard are primarily attributed to Qualcomm.

First, let's define what a signal prediction model is in the context of wireless communication. A signal prediction model is a mathematical formula or algorithm used to estimate the received signal strength at a specific location in a wireless communication system. These models are crucial for planning and designing wireless networks, ensuring adequate signal coverage and minimizing interference. The correct answer is A: Okumura model . The Okumura-Hata model (often shortened to just Okumura model) is an empirical model that is widely used for predicting path loss in urban areas. It's based on extensive measurement data collected in Tokyo, Japan. Its popularity stems from its relative simplicity and reasonable accuracy for many urban environments. It considers various factors affecting signal propagation, such as frequency, distance from the transmitter, and the type of environment (urban, suburban, rural). While not perfect, its ease of use and relatively good accuracy for a wide range of scenarios make it a preferred choice for initial estimations in urban planning. Now let's address why other options are less suitable: Option B: Attenuation factor model: This is a more general term and doesn't represent a specific, widely used model like Okumura. Attenuation factors are components within various models, but they don't stand alone as a complete predictive model. Option C: Ericsson Multiple Breakpoint Model: While a valid model, it's not as widely used or established as the Okumura model. It might be preferred in certain specific scenarios or by particular vendors, but it lacks the general acceptance and broad application of the Okumura model. Option D: Log distance path loss model: This is a very basic model, suitable for simple estimations but often lacking the accuracy and detail needed for realistic urban environments. It primarily accounts for distance-based signal attenuation, neglecting crucial factors like terrain, building density, and other environmental effects significant in urban areas. The Okumura model, on the other hand, incorporates these factors, leading to more precise predictions. In summary, while several models exist for signal prediction, the Okumura model stands out due to its widespread use, relative simplicity, and acceptable accuracy for urban environments, making it the most appropriate answer.

First, let's define 2G (Second Generation) wireless technology. 2G refers to the second generation of cellular network technology. It's a significant improvement over its predecessor (1G), offering improved digital voice quality, increased capacity, and data transmission capabilities, though at a relatively lower speed compared to later generations (3G, 4G, 5G). Now, let's examine the options: Option A: IS-136 - This is a TDMA (Time Division Multiple Access) based 2G standard, primarily used in North America. Option B: GSM (Global System for Mobile Communications) - This is a widely adopted 2G standard, used globally, but not originally in Japan. Option C: PDC (Personal Digital Cellular) - This is the correct answer. PDC is a TDMA-based 2G standard that was specifically developed and deployed in Japan. Option D: AMPS (Advanced Mobile Phone Service) - This is an older 1G analog cellular technology, not a 2G standard. Therefore, the correct answer is Option C: PDC because it was the dominant 2G cellular standard used in Japan before the widespread adoption of 3G and beyond. While GSM is a global standard, PDC held its own in the Japanese market for a considerable period.

W-CDMA (Wideband Code Division Multiple Access) is a 3G mobile communication technology that utilizes code division multiple access (CDMA) to allow multiple users to share a single frequency band. FDD (Frequency Division Duplex) is a duplexing method where the uplink (from mobile device to base station) and downlink (from base station to mobile device) transmissions occur on separate frequency bands. The statement "W-CDMA works in FDD mode only" is False . While W-CDMA is predominantly used in FDD mode, it is also capable of operating in TDD (Time Division Duplex) mode. In TDD, the uplink and downlink transmissions use the same frequency band but are separated in time. Therefore, the statement is incorrect because W-CDMA's functionality extends beyond FDD to include TDD operation. The flexibility to operate in both modes makes it adaptable to different network deployments and frequency allocation scenarios.

3G Standard: 3G (Third Generation) refers to the third generation of mobile telecommunications technology, offering higher speeds for data transmission and more efficient wireless communication compared to its predecessors. Option A: Cdma2000 Cdma2000 is a 3G mobile telecommunications standard based on code-division multiple access (CDMA). It is widely used in North America and some parts of Asia, including South Korea. However, it is not the primary 3G standard used in Japan. Option B: TD-SCDMA TD-SCDMA (Time Division Synchronous Code Division Multiple Access) is a 3G standard primarily used in China. It is a homegrown Chinese technology and not the standard used in Japan. Option C: UMTS UMTS (Universal Mobile Telecommunications System) is a 3G standard used in Europe and other parts of the world. It uses WCDMA (Wideband CDMA) as its air interface technology. Although it is a common 3G standard, it is not the standard used in Japan. Option D: UTRA UTRA (UMTS Terrestrial Radio Access) is the radio access technology used in UMTS. It is not a standalone 3G standard but part of the UMTS framework. Since UMTS is not the primary standard in Japan, UTRA is also not the answer. Correct Answer: Option A: Cdma2000 Japan predominantly uses Cdma2000 for its 3G services. The country's major telecom operators, such as KDDI, have adopted this standard for efficient mobile communication.

Paging System Definition: A paging system is a one-way communication technology that allows a message to be sent to a specific person or group of people. Unlike two-way communication systems like telephones or walkie-talkies, paging systems only allow for the receiving party to hear the message; they cannot respond. Correct Answer: Option A, Al Gross Al Gross is credited with introducing the first paging system. While the exact details of its initial implementation might vary depending on the source, he is widely recognized as a pioneer in the development and commercialization of early paging technology. His contribution involved developing a system that could send short messages to individuals equipped with receivers. These early systems were rudimentary compared to modern pagers, but they laid the foundation for the technology’s widespread adoption. Why other options are incorrect: Option B: Teri Pall - There's no widely known or documented evidence linking Teri Pall to the invention or introduction of the paging system. Option C: Alexander Graham Bell - While Alexander Graham Bell is a pivotal figure in the history of telecommunications, his work primarily focused on the telephone, a two-way communication device. He's not associated with the development of paging systems. Option D: Martin Cooper - Martin Cooper is credited with making the first successful handheld cellular phone call. While both cellular phones and pagers are wireless communication technologies, they are distinct and serve different purposes. Cooper's work is related to two-way mobile communication, whereas paging is a one-way system.

Bit Error Rate (BER) is defined as the ratio of the number of bits received in error to the total number of bits transmitted during a specific period. The question asks which option is specified by a specific number of bit errors in a given transmission. The correct answer is Option C: Bit Error Rate . BER directly relates the number of bit errors to the total number of transmitted bits. A higher BER indicates a worse communication channel quality, with more errors occurring during transmission. Let's look at why the other options are incorrect: Option A: Equally likely event refers to a situation where each possible outcome of an event has the same probability of occurrence. This is a probabilistic concept and doesn't directly define a specific number of bit errors. Option B: Exhaustive events describes a set of events where at least one of the events *must* occur. This is also a general probabilistic concept, not directly tied to a count of bit errors. Option D: Outage event refers to a situation where the signal quality falls below a predetermined threshold, rendering the communication link unusable. While an outage event often *results* from a high bit error rate, it's not directly defined by a *specific* number of bit errors. An outage is triggered when the BER exceeds a certain level, but it doesn't describe a specific number of bit errors itself.

W-CDMA (Wideband Code Division Multiple Access): W-CDMA is a 3G mobile communication technology that uses code division multiple access for transmitting data. It provides higher data rates and supports better voice and data communication compared to earlier technologies. W-CDMA is a part of the UMTS standard, which is used in many countries worldwide. W-CDMA requires upgrades to existing base station equipment rather than a complete change, making "False" the correct answer.

EDGE (Enhanced Data rates for GSM Evolution): EDGE is a 2.5G technology that improves upon the original GSM (Global System for Mobile Communications) standard by enabling higher data rates and more efficient packet-oriented data transmission. It enhances the data capabilities of GSM networks, providing better performance for mobile internet and multimedia services compared to basic GSM. HSCSD (High-Speed Circuit-Switched Data): HSCSD is a 2G technology that enhances GSM by using multiple time slots for each data transmission. This enables faster data rates than standard GSM, though it still relies on circuit-switched technology for data transfer. GPRS (General Packet Radio Service): GPRS is another 2G technology that improves data transmission by using packet switching instead of circuit switching, making it more efficient for bursty data services, like browsing the web and sending emails. Explanation of the Correct Answer: Option A: Low data rates This is the correct answer. While EDGE does improve upon GSM with better data rates, its speeds are still lower compared to HSCSD and GPRS, especially under optimal conditions. HSCSD uses multiple time slots to increase data transfer rates, achieving faster speeds than EDGE. GPRS, although slower in some cases, is generally more efficient in bursty data scenarios, which can sometimes give it an edge over EDGE in real-world usage. Despite its improvements, EDGE still cannot compete with the higher data rates achievable by more advanced technologies. Option B: Small coverage range This option is incorrect. The coverage range for EDGE is generally similar to that of GPRS and HSCSD, as they all operate within the same GSM infrastructure. The coverage is primarily determined by the base station's signal strength and the terrain, not by the data transmission technology. Option C: Low speed This option is partially correct but misleading. EDGE is slower than 3G and 4G technologies, but it is not necessarily slower than HSCSD or GPRS. The data speed of EDGE depends on specific conditions and the implementation of the technology, making it comparable to or sometimes faster than HSCSD or GPRS, particularly in non-ideal network environments. Option D: No advancement This option is incorrect. EDGE is considered an advancement over the original GSM standard because it improves data transmission capabilities, enabling faster internet and multimedia services. It represents a significant step forward, even though it is a transitional technology before the adoption of 3G and beyond. Correct Answer: Option A: Low data rates While EDGE offers improvements over GSM, its data rates are still lower than those provided by HSCSD and GPRS in certain conditions. HSCSD achieves faster speeds by using multiple time slots, and GPRS is more efficient for bursty data transfers, making EDGE less advantageous in terms of data rate in comparison.

High complexity and high power transmitter, low complexity and low power receivers is the correct answer to “Which of the following properties describes the transmitters and receivers in paging system”. This question is standard in competitive examination syllabi for Wireless Communication.

IS-95 is the correct answer to “Which of the following standard had not adopted digital TDMA for high capacity”. This question is standard in competitive examination syllabi for Wireless Communication.

MIN, ESN and SCM is the correct answer to “What is transmitted along with the call initiation request during the origin of call by a mobile”. This question is standard in competitive examination syllabi for Wireless Communication.

Cordless telephone system is the correct answer to “Which of the following is an example of local wireless system”. This question is standard in competitive examination syllabi for Wireless Communication.

LTE is the correct answer to “Which of the following is not a standard of 3G”. This question is standard in competitive examination syllabi for Wireless Communication.

Video message is the correct answer to “Which type of message cannot be sent with the help of paging system”. This question is standard in competitive examination syllabi for Wireless Communication.

IS-95 is the correct answer to “Which of the following is not a standard used for paging system”. This question is standard in competitive examination syllabi for Wireless Communication.

Connection of mobile to PSTN is the correct answer to “What is the responsibility of MSC in cellular telephone system”. This question is standard in competitive examination syllabi for Wireless Communication.

Project based on W-CDMA is the correct answer to “What is 3GPP”. This question is standard in competitive examination syllabi for Wireless Communication.

Interference and noise is the correct answer to “What is the main disadvantage of RF pulse system”. This question is standard in competitive examination syllabi for Wireless Communication.

5 MHz is the correct answer to “What is the minimum spectrum allocation required by W-CDMA”. This question is standard in competitive examination syllabi for Wireless Communication.

Cdma2000 is the correct answer to “Which of the following leads to evolution of 3G networks in CDMA systems”. This question is standard in competitive examination syllabi for Wireless Communication.

HIPERLAN/2 is the correct answer to “What is the name of the European WLAN standard that provides user data rate upto 54 Mbps”. This question is standard in competitive examination syllabi for Wireless Communication.

2.048 Mbps is the correct answer to “How much packet data rate per user is supported by W-CDMA if the user is stationary”. This question is standard in competitive examination syllabi for Wireless Communication.

Multimedia processing is the correct answer to “Which of the following is not an application of DECT”. This question is standard in competitive examination syllabi for Wireless Communication.

False is the correct answer to “Cdma2000 works in TDD mode only.”. This question is standard in competitive examination syllabi for Wireless Communication.

Simplex is the correct answer to “Paging system uses which mode of transmission”. This question is standard in competitive examination syllabi for Wireless Communication.

Twice is the correct answer to “How many users are supported by Cdma2000 1X in comparison to 2G CDMA standard”. This question is standard in competitive examination syllabi for Wireless Communication.

IS-95B is the correct answer to “Which of the following is a 2.5G CDMA standard”. This question is standard in competitive examination syllabi for Wireless Communication.

CDMA is the correct answer to “UMTS use which multiple access technique”. This question is standard in competitive examination syllabi for Wireless Communication.

10 m is the correct answer to “What is the nominal range of Bluetooth”. This question is standard in competitive examination syllabi for Wireless Communication.

GSM is the correct answer to “HSCSD supports which 2G standard”. This question is standard in competitive examination syllabi for Wireless Communication.

GFSK is the correct answer to “Which modulation scheme is used by Bluetooth”. This question is standard in competitive examination syllabi for Wireless Communication.

Switching Technique is the correct answer to “How is HSCSD different from GPRS”. This question is standard in competitive examination syllabi for Wireless Communication.