2.4 Multiplexing and Multiple Access

Question 1

What is multiplexing

Answer 1

Combines multiple signals into one signal for transmission on a single channel.

Question 2

Time Division Multiplexing

Answer 2

Uses a recurring length of time - “frame”
Each signal gets a time slot within the frame

Must operate very quickly to avoid large delays at the receiver.

Question 3

Frequency Division Multiplexing

Answer 3

FDM takes a given BW and devides it into smaller channels.
Each signal gets a channel.
Guard bands are placed between bands to prevent interference.

Question 4

Multiple Access

Answer 4

Multiple sources share a single channel IOT access a remote resource or channel.

Instead of everybody transmitting on the same channel, everybody can receive on the same channel.

Question 5

Code Division Multiple Access (CDMA)

Answer 5

Signal is converted to spread spectrum where they will not interfere with each other. Code is used to spread and de-spread.

All users occupy the same frequency and time but are separated from each other by means of a code.

Question 6

Frequency Division Multiple Access (FDMA)

Answer 6

Available bandwidth is devided into separate channels. Each channel is assigned to remote stations. It is the same as FDM except we are talking about receiving.

Guard bands are used to prevent interference between channels.