1 access channel
1 communication channel
Data transfer speedin the synchronization
channelpersonal call and usechannelon
the communication channel
|
1200 bit/s
9600,4800 bit/s
9600,4800,2400,1200 bit/s
|
Coding in BTS transmission channels(sync. channel. personal call. connection)
|
High-precision coding r= ½,K = 9
|
Coding in MS transmission channels
|
U = 1/3, K = 9 64 lamchi with Walsh signalcoding
|
The bit energy of the information in the receivernoise spectral density ratio (En / N0)
|
6 – 7 dB
|
Maximum effective transmission power of BTS
|
50 W each
|
The maximum effective transmission power of MS is
1 class
2 class
3 class
|
6,3 W
2,5 W
1,0 W
|
Power control accuracy of MS transmitter
|
+/- 0,5 dB
| - The history of CDMA goes back to the distant 30s of the 20th century, when the Soviet academician Ageev Dmitry Vasilyevich published his work entitled "Code Channel Separation". At that time, there was only a method of frequency division.In the 40s, research on this topic was conducted in the USSR and the USA, and the first steps were taken on the path to the latest communication technologies.In the 1950s, the first equipment using code division appeared in the USA. Initially, it was used only in military systems, and it was only in the 80s that the US military declassified the technology.
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