Techniques for assigning acknowledgement (ACK) resource to a user equipment (UE) in a wireless communication system are described. In one design, a first parameter indicative of radio resources (e.g., the lowest index of at least one physical resource block) allocated to the UE for data transmission may be obtained. A second parameter indicative of another resource (e.g., a cyclic shift of a reference signal sequence) assigned to the UE for data transmission may also be obtained. The first and/or second parameter may be restricted, and each restricted parameter may be limited to a set of allowed values among all available values for the parameter. ACK resource assigned to the UE for data transmission may be determined based on the first and second parameters. In one design, sequential first parameter values may be mapped to sequential ACK resources indices. In another design, mirror mapping with different mapping directions may be used for different allowed values of the second parameter.