计算机网络CDMA练习题(Computer network CDMA exercises)
计算机网络CDMA练习题(Computer network CDMA exercises)
The first chapter
What are the three main standards of 3G?
The second chapter
2.1 explain how the code division multiple access works?
2.2 what are the three key technologies of cdma?
2.3 why must the code division be combined with spread spectrum technology?
The system wants to transmit C = 64kbit/s data, the signal noise ratio s/N = 15dB, what is the theoretical channel bandwidth? What is the channel bandwidth if the signal-to-noise ratio is equal to -10db?
2.5 a spread spectrum communication system of the spread spectrum signal bandwidth W and information is W = 20 MHZ bandwidth B, B = 10 KHZ, such as system loss LS = 3 db, the receiver output letter receiver output signal-to-noise ratio (S/N) > = 10 db, then the system of spread spectrum gain and interference tolerance is how much?
11 what is spread spectrum gain? What is its physical significance?
What are the interference tolerance? What does the system's interference tolerance mean?
What are the characteristics of the spread-spectrum communication system?
What is direct sequence spread spectrum communication? What is the anti-interference mechanism of direct sequence ampliation communication?
16. How does direct sequence spread spectrum communication combine with multi-address?
17 what is frequency hopping? How does frequency-hopping spread spectrum communication system make up?
Why is the frequency amplifable communication system resistant to interference?
Chapter iii code sequence
What characteristics should the ideal address code and spread code have?
What is the two Walsh? How is it generated?
Why can't the Walsh code be used as a spread code?
Try to write the walshard matrix of 8.
5 what is m sequence? How is it generated?
6. What is the period of the m sequence generated by the 4-step shift register? How many m sequences are there?
There is an m sequence that generates a polynomial of G4 (x) = 1 + x1 + x4, and try to draw the corresponding generation circuit