Using Direct Sequence Spread Spectrum: 2.4-GHz Channels for Collision Limitation

2.4-GHz Channels for Collision Limitation

Question

Using direct sequence spread spectrum, which three 2.4-GHz channels are used to limit collisions?

Answers

Explanations

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A. B. C. D.

C

Direct sequence spread spectrum (DSSS) is a wireless networking technology that spreads a signal across multiple frequencies to increase the reliability of data transmission and reduce the likelihood of interference or collisions. In the 2.4 GHz frequency band, DSSS uses 14 channels that are spaced 5 MHz apart, each with a bandwidth of 22 MHz.

To limit collisions in DSSS, it is recommended to use channels that do not overlap with each other. The channels that do not overlap in the 2.4 GHz frequency band are 1, 6, and 11. These channels are sometimes referred to as non-overlapping or orthogonal channels.

Using non-overlapping channels reduces the likelihood of interference or collisions because devices on different channels can communicate simultaneously without interfering with each other. For example, if two devices are on channel 1 and a third device is on channel 6, the device on channel 6 will not cause interference with the devices on channel 1.

Therefore, the correct answer to the question is C. 1, 6, 11. Channels 5, 6, and 7 (option A) are adjacent channels that partially overlap, while channels 1, 2, and 3 (option B) overlap completely with each other. Channel 10 overlaps with channels 6 and 11, making it a poor choice for limiting collisions.