A system and method for wireless communication over multi-rate channels are disclosed. One embodiment of the system includes source and destination devices that use first and second channels under a contention-based protocol. The first channel is directional with a first frequency and a first range. The second channel is omni-directional with a second frequency and a second range. The second frequency is lower than the first frequency, and the second range is greater than the first range. The source device may send the destination device a request for data transmission via the first channel over the second channel. The destination device may send the source device an approval for the data transmission over the second channel. The source device may further transmit an acknowledgment (ACK) of the approval over the second channel upon receiving the approval to prevent other devices in the system from contending for data transmission.