A method and a system for medium access control among devices in a communication system is provided. One implementation involves selecting a contention-based control period for access to a shared communication medium; dividing the contention-based control period into multiple time slots, wherein each slot has a duration that is a function of one or more of the duration of transmission of a request to send (RTS) frame, the duration of transmission of a clear to send (CTS) frame, and an inter frame space (IFS) duration therebetween; and transmitting an RTS frame in a selected slot for allocating a reservation period for accessing the medium for data transmission.