3A

Question 1

___ are complex communications vehicles that enable the passing of information to-and-
from geographically separated locations.

Answer 1

Satellites

Question 2

The term “___ ___” is derived from the satellite’s ability to multiplex signals from numerous terminals in a variety of ways.

Answer 2

multiple access

Question 3

was the first access method to be developed and continues to be widely used in today’s
satellite communications.

Answer 3

Frequency Division Multiple Access (FDMA)

Question 4

During FDMA, terminals are separated by ___ inside of the
channel’s allocated bandwidth.

Answer 4

frequency

Question 5

In between distinct user’s frequencies lie ___ ___, whose purpose is to minimize crosstalk by spacing out users.

Answer 5

guard bands

Question 6

While FDMA is advantageous to support connection-oriented applications, this access method can be spectrally inefficient for the satellite’s
total capacity due to…?

Answer 6

users not constantly utilizing their frequency.

Question 7

functions by assigning terminals dedicated time slots on a channel’s bandwidth, as opposed to dedicating a frequency to each user.

Answer 7

Time Division Multiple Access (TDMA)

Question 8

While using this access method, there is time separating each slot that acts as the ___ ___.

Answer 8

guard band

Question 9

To effectively employ TDMA, stringent ___ and ___ ___ must be in place.

Answer 9

timing and network controls

Question 10

operates as a spread spectrum technique that uses pseudorandom noise codes to separate its users.

Answer 10

Code Division Multiple Access (CDMA)

Question 11

During CDMA operation, all terminals transmit at the ___ ___, over the same frequency. However, the receiving terminal actively looks for a specific coded waveform from the
desired transmitter. This allows multiple users to transmit at the same time.

Answer 11

same time

Question 12

Uses wider frequency bands than CDMA, so it can achieve higher throughput for data transmission. The input signals are digitized and
transmitted in coded, spread-spectrum mode over a broad range of frequencies.

Answer 12

Wideband Code Division Multiple Access (WCDMA)

Question 13

A 5 MHz-wide carrier is used for this access.

Answer 13

WCDMA

Question 14

A 200 KHz-wide carrier for narrowband is used for this access.

Answer 14

CDMA

Question 15

Is CDMA synchronous or asynchronous?

Answer 15

synchronous

Question 16

Is WCDMA synchronous or asynchronous?

Answer 16

asynchronous

Question 17

Operates on a first come, first serve basis. Transponder capacity is allocated to users on an as-needed basis. After the information has been communicated, the frequency is then returned to a pool where it can be used by the next user who needs to pass information.

Answer 17

Demand Assigned Multiple Access (DAMA)