Chapter 06 Wireless Networking

The wireless spectrum is defined by the Federal Communication Commission (FCC) as a range of frequencies or bands. What is the range of frequencies?

• 50 kHz and 500 kHz

• 9 mHz and 300 THz

• 9 kHz and 300 GHz

• 1 kHz and 300 GHz

Answer explanation

The wireless spectrum, as defined by the FCC, ranges from 9 kHz to 300 GHz. This range encompasses various frequencies used for communication, making '9 kHz and 300 GHz' the correct choice.

When multiple wireless devices transmit a signal at the same time on the same frequency, signals can interfere with one another, which is called a collision. Why do collisions reduce network performance?

• the signal breaks apart

• the signal degrades

• the signal bounces around the network

• the signal must be retransmitted

Answer explanation

Collisions require the affected devices to retransmit their signals, which leads to delays and reduced overall network performance. This is why the correct answer is that the signal must be retransmitted.

Which wireless technology transmits short bursts of data on a particular frequency within the band and then moves to the next frequency in the sequence?

• FHSS (frequency hopping spread spectrum)

• DSSS (direct sequence spread spectrum)

• MIMO (multiple input multiple output)

• OSPF (open shortest path first)

Answer explanation

FHSS (frequency hopping spread spectrum) transmits data by rapidly switching frequencies, allowing for secure and efficient communication. This method contrasts with DSSS, which spreads data over a single frequency.

Which wireless technology divides data streams and encodes them into small chunks called chips, which are spread over all available frequencies at the same time?

• FHSS (frequency hopping spread spectrum)

• MIMO (multiple input multiple output)

• DSSS (direct sequence spread spectrum)

• Omnidirectional sequence

Answer explanation

DSSS (direct sequence spread spectrum) divides data into small chunks called chips, which are then spread across all available frequencies simultaneously, making it the correct choice for this question.

What is the term for the geographic area that can be covered by an antenna or wireless system?

• omnidirectional location

• frequency

• reach

• range

Answer explanation

The term 'range' refers to the geographic area that an antenna or wireless system can effectively cover. It indicates the distance over which the signal can be transmitted and received, making it the correct choice.

Jackson needs to set up a dedicated Wi-Fi signal for his company's conference room using a point-to-point transmission. Which antenna should he use?

• unidirectional

• omnidirectional

• narrow directional

• DSSS directional

Answer explanation

Jackson should use a unidirectional antenna for point-to-point transmission, as it focuses the signal in one direction, providing a stronger and more reliable connection for the conference room.

RSSI measures the power of the signal on the receiver's end and is displayed as negative dBm values. The scale used for RSSI measurement varies by manufacturer but typically, RSSI is displayed as negative numbers. What would be the best rating of the four numbers below?

• -90 dBm

• -70 dBm

• -50 dBm

• -30 dBm

Answer explanation

RSSI values are negative, with closer to zero indicating a stronger signal. Among the options, -30 dBm is the least negative, representing the best signal strength compared to -50, -70, and -90 dBm.

As a wireless signal moves away from the transmission source, it becomes weaker. What is this phenomenon called?

• fading

• interference

• attenuation

Answer explanation

The phenomenon where a wireless signal weakens as it travels away from the source is called attenuation. This term specifically refers to the reduction in signal strength over distance.

As a wave travels into and through a different transmission medium, such as when traveling through glass or other solids, the wave's direction, speed, and wavelength are altered. What is this phenomenon called?

• fading

• reflection

• interference

• refraction

Answer explanation

The phenomenon where a wave changes direction, speed, and wavelength as it enters a different medium is called refraction. This occurs due to the change in the wave's velocity in different materials.

When the wave encounters an obstacle and reflects, or bounces back, toward its source, a wireless signal will bounce off objects whose surface dimensions are large compared with the signal's average wavelength. Fill in the blank: This phenomenon is called ________.

• reflection

• diffraction

• refraction

• absorption

Answer explanation

When a wave encounters an obstacle and bounces back, it is called reflection. This occurs when the object's surface is large compared to the wavelength, allowing the signal to return toward its source.