Communication devices, such as base nodes and modems, that comply with two or more different standards operate on a shared communication channel. To avoid mutual interference, a base node operating under a first standard reserves time using a contention free period designation. The base node allows devices operating under a second standard to communicate during the reserved time by not assigning the contention free period to another device operating under the first standard. Alternatively, a device using the first standard may avoid interference from transmissions generated under the second standard by modifying data packets prior to transmission. A prefix corresponding to a preamble in the second standard is added to the beginning of the data packet created under the first standard. Devices operating under the second standard observe the prefix and recognize that the channel is active. The second-standard devices backoff from transmission thereby minimizing interference.
