Airtime in wireless communication

[Bharatsiingh]

My Question is:

At wireless core, communication is half duplex because only 1 device can send packet at one time. My first question is very very simple but i need a pure technical authorative answer for my own curiosity

1. Assuming we have 2 or more clients, what determines how much transmit time each client gets ? meaning, how much time does client 1 gets to transmit ?  
2. Based on above's answer, i may need to ask, is there anyway client 1 can starve client 2 and client 3 but not giving them any chance to transmit at all ? does it happens ?

[cjoseph]

1.  A very technical discussion of that is here:  https://www.cwnp.com/uploads/802-11_arbitration.pdf

2.  I have seen clients dominate the medium when they are closer to the access point, because their packets are more likely to be successfully transmitted.  I have never seen any clients that are not able to transmit at all, however..