Week 1 iLab Report
NETW360: Wireless Technologies and Services
OPNET Preparation and Spread Spectrum Transmission Comparison
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OPNET Preparation
OPNET Preparation
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Spread Spectrum Transmission Comparison
Introduction to Spread Spectrum Transmission
Guidelines
* What is it? Why is it important? What issues are addressed? How does it work?
Spread Spectrum is compared to narrowband transmission because narrow only sends signal through a small portion where spread spectrum sends a weaker signal across a bigger portion of the radio frequency band. Some of the issues it addresses are the fact that it is quite resistant to interference, low power needed, more information transferred and it has security. The textbook explains this as lanes of highway, if one lane is blocked there are other lanes in the spectrum that can be used. Spread-Spectrum uses three methods to spread signal which are frequency hopping, direct sequence, and orthogonal frequency division multiplexing.
Frequency Hopping Spread Spectrum (FHSS)
Guidelines
* What is it? How does it work? What issues are addressed? Why is it important?
Frequency hoping works by using a range of frequencies that change during transmission. This is carried out by continuous short burst until the transmission has been completely sent. The use of this type of method addressed an issue with signals being jammed. With the uses of a dwell time, hop time, and hoping code allowed for the U.S military to communicate without being interfered because if a signal was interfered it would just be resent on the next hop. FHSS also works on a set of rule through the 2.4ghz band and also the 900mhz band. This type of transmission is important because it is considered secret.
Direct Sequence Spread Spectrum (DSSS)
Guidelines
* What is it? How does it work? What issues are addressed? Why is it important?
DSSS uses a spread spectrum is explained by the textbook as using a repetitive bits code of ones and zeros. It also uses chipping codes that in only 11 or 22 bits. With FHSS if an error was made it had to be transmitted but with DSSS it can recover data from multiple bits in a transmission. It also can “share” its frequency band with other devices, has security and is prone to less interference.
Comparison between FHSS and DSSS Technique | Advantages | Disadvantages | FHSS | Hard to cause interference and has its own method of error correction. Can share frequency. | Has very limited speed and more than likely why used in Bluetooth technology. | DSSS | Has good error correction..
Greater transmission speed.Works with other devices in its frequency range. Has strong transmission code that is difficult to decipher. | If original data was bit was recovered it is easily read. |
Guidelines: Summarize what was learned in a concise table format.
Conclusion
Guidelines: Include a minimum of one paragraph; best practice is two or more paragraphs. * What did you learn? How does it relate to this week’s TCOs and course material? Why is it important? How do you feel it will benefit you in your academic and professional career?
Well chapter 1 discussed the different uses of WPAN, WLAN, WMAN,and WWAN which all can use some portion of wireless modulation technologies. I feel like this gave me a better understanding and side by side comparison of each of the technologies methods. I can now properly explain what spread spectrum is and how FHSS, DSSS work among the spectrum. By knowing how these transmissions work gives me options on what to use and how they work whether it be with my personal devices or in the work field.
References
Guidelines
* Include all references used to complete this iLab. This must be in APA format. 