Abstract: The invention provides a method and system for extending channel access in a wireless communications system employing half duplex subscriber units. The subscriber units transmit multi-block bursts to improve the burst throughput over half duplex subscriber units that transmit only single-block bursts. The number of blocks per burst is selected based on the code rate used and may be selected in a manner that also maximizes the system throughput. The subscriber unit includes a block processor for assembling the blocks of data with overhead based on the code rate, a burst formatter for combining the blocks and formatting the combination based on the code rate, and a process manager for selecting the number of blocks to be transmitted in each transmit burst.