Techniques for efficiently assigning resources for spurts of traffic in a wireless communication system are described. The system may support semi-persistent and non-persistent resource assignments. A semi-persistent resource assignment is valid for as long as more data is sent within a predetermined time period of last sent data and expires if no data is sent within the predetermined time period. A non-persistent resource assignment is valid for a predetermined duration or a specific transmission. A semi-persistent resource assignment may be granted for an expected spurt of data to send via the communication link. For Voice-over-Internet Protocol (VoIP), a semi-persistent resource assignment may be granted for a voice frame in anticipation of a spurt of voice activity, and a non-persistent resource assignment may be granted for a silence descriptor (SID) frame during a period of silence.