Spread Spectrum Transmission Comparison

OPNET Preparation

OPNET Preparation

Spread Spectrum Transmission Comparison

Spread Spectrum is a means of transmission that resists jamming and is hard to be intercepted. The signals, which are distributed over a wide range of frequencies,(which are hidden behind other waves) are then collected onto their original frequency at the receiver which will read the information and use the code to translate the data.

Spread Spectrum uses wide band, noise like signals which makes them hard to detect also hard to Intercept or demodulate. The Spread signals are intentionally made to be much wider, than the information they are carrying. Directional antennas can sometimes help a node focus on the system with which it must communicate and ignore interference from others. However, when two transmitters compete for the same bandwidth, the one that expends more energy per bit of data wins the conflict.

Frequency Hopping Spread Spectrum (FHSS)

In frequency Hopping Spread Spectrum the carrier automatically hops from frequency to frequency. This allows the transmission to occur over several frequencies which lets data roll over a certain amount of in-band interference providing that it affects only part of the scale. FHSS has its own frequencies and hop sequence, the chances of two remotes on the same frequency is greatly reduced. If a hop clash does occur the remote messages are corrupted, but the probability that both remotes will hop the second time is very unlikely. FHSS is modified by the carrier periodically following specific frequencies. The frequency has a different value for each dwell time and only the receiver can read and interpret the data. FHSS has a narrow band signal for each dwell time but generates a wide band signal for the data. Redundancy is achieved through the possibility to execute retransmission on different hops.

Direct Sequence Spread Spectrum (DSSS)

Direct Sequence Spread Spectrum transmission multiplies the data being...