Techniques for sending control information in a wireless communication system are described. A control segment may include L≧1 tiles, and each tile may include a number of transmission units. A number of control resources may be defined and mapped to the transmission units for the control segment. For symmetric mapping, multiple sets of S≧1 control resources may be formed, and each batch of L consecutive sets of S control resources may be mapped to S transmission units at the same location in the L tiles. For localized mapping, S>1, and each set of S control resources may be mapped to a cluster of S adjacent transmission units in one tile. For distributed mapping, S=1, and each control resource may be mapped to one transmission unit in one tile. For diversity, each control resource may be mapped to multiple (e.g., three) transmission units in at least one tile.