US Patent 8194696 Method and apparatus for scheduling an acknowledgement transmission

A communication system distributes, in the time domain, acknowledgment transmissions by a group of access terminals sharing a same time domain resource. A position of one or more access terminals in the group of access terminals is determined and each of the one or more access terminals then sends an acknowledgment transmission, such as an acknowledgment or negative acknowledgement, in a time slot that is N time slots after the shared time domain resource, where N is a function of the position of the access terminal in the group of access terminals.