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multiplexing, duplexing - Coggle Diagram
multiplexing
CDMA
spread-spectrum
spreading code
spreading code is a pseudo-random code that has a narrow ambiguity function, unlike other narrow pulse codes.
The data signal with pulse duration of {\displaystyle T{b}}T{b} (symbol period) is XORed with the code signal with pulse duration of {\displaystyle T{c}}T{c} (chip period). (Note: bandwidth is proportional to {\displaystyle 1/T}1/T, where {\displaystyle T}T = bit time.
The ratio {\displaystyle T{b}/T{c}}{\displaystyle T{b}/T{c}} is called the spreading factor or processing gain and determines to a certain extent the upper limit of the total number of users supported simultaneously by a base station
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FDMA
Frequency Division Multiple Access
FDMA which uses frequency division multiplexing, provides chunks of the frequency spectrum to each user for data transmission.
AMPS or the first generation analog systems used FDMA to provide each user a duplex channel with one way bandwidth of 30 kHz.
TDMA
Ця технологія застосовувалася в системах 2G, таких як GSM, GPRS та EDGE.
Multiplexing is the process of combining multiple signals and transmitting them over a common channel
duplexing
types
FDD
FDD: дуплекс с частотным разделением (FDD) - это метод для установления полнодуплексной линии связи, которая использует две разные частоты несущей радиосвязи для передачи UPLINK и приема DOWNLINK.
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TDD
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