N-GEN Communications Web-based Seminars ©NGCS

Seminar - An Overview of Communications Technologies

Module 9 - Wireless Systems and Technologies                                                                                   Slide 9 of 80                                                                                                    ________________

    Time Division Multiplexing Access (TDMA)

NIU - Network Interface Unit

                                 Multiple customer sites share both downstream
                                                                   and upstream

                                                                                                   ________________

In Time Division Multiplexing Access (TDMA) technique the available spectrum may be used as a single channel or subdivided into a number of channels. Each channel can support multiple users assigned to different time slots on the channel.

Example: Advanced Mobile Phone Service (Digital)

Channel Capacity:  - 48,600 bps
                            - 6 time slots at 8 K bps
                            - 24.3 K bps in each direction
                            - 3 conversations on each channel in each direction
                              (3x8000 bits per channel with 8000bper digitization)
                            - Can support 6 conversations in each direction with 4000 bps digitization of speech