Communication apparatus includes a transceiver configured to transmit and receive signals over a wireless channel in accordance with both a first communication protocol and a second communication protocol. The second communication protocol is backward-compatible with the first communication protocol, and has a first variant having an extended communication throughput, which is greater than the nominal communication throughput of the first protocol, and a second variant having an extended range, which is greater than the nominal range of the first protocol. A communication controller generates data frames for transmission by the transceiver, including frame headers in a header format that is compatible both with the first communication protocol and with both the first and second variants of the second communication protocol. The header format defines first fields having respective first values provided to support the first variant and second fields having respective second values provided to support the second variant.