Multiple access(TDMA,CDMA, FDMA) or Cellular concept

The cellular concept, also known as cellular radio, refers to the idea of dividing a geographical area into small sections, each called a cell. Each cell has its own transmitter and receiver, allowing for multiple simultaneous transmissions in different cells. This concept is the basis for modern mobile communication.

1. TDMA (Time Division Multiple Access): This is a type of digital multiple access method where the available bandwidth is divided into time slots. Each user is assigned a specific time slot during which they can send or receive data. This prevents interference from multiple users transmitting at the same time.

2. CDMA (Code Division Multiple Access): In CDMA, every conversation is modulated with a unique code. This allows multiple users to share the same frequency band simultaneously. Each receiver only listens to the specific coded signal and ignores others. This method is highly efficient and provides a high degree of privacy.

3. FDMA (Frequency Division Multiple Access): FDMA divides the total bandwidth into different frequency bands. Each user is assigned a specific frequency band. This method allows multiple users to transmit simultaneously, but each user is limited to their assigned frequency band.

In summary, these multiple access methods are techniques that allow multiple users to share the available bandwidth in a communication system. They are fundamental to the operation of cellular networks.