Don't understand the relation about the wireless communication flow chart and TDMA illustration diagram
TDMA wraps around the outside of your block diagram of the communication link.  There are $M$ users who are buffering the data that they wish to transmit. The TDMA switch at the input selects each user in turn and connects its buffer to the block marked Source Coding for a fixed amount uf time. During this time, the contents of the user's buffer are source coded, channel coded, transmitted etc.  When the user's time is up, the TDMA switch connects the next user's buffer to the Source Coding block, etc.  At the receiver end, there is a synchronous switch that routes the Source Decoder's output to the appropriate user's buffer which the user empties at a lower rate (if it so chooses so that it gets its data at a constant rate rather than in bursts).