US Patent 7940794 Dynamic channel bandwidth management

To provide an extra wide bandwidth communication using standard channels, multiple non-overlapping channels can be used. To provide a 40 MHz communication, two non-overlapping 20 MHz channels, i.e. a control channel and an extension channel, can be used to provide an effective 40 MHz channel. Advantageously, a wireless device can dynamically detect 20/40 MHz signals on a packet-by-packet basis, thereby facilitating commercially viable 40 MHz communication. The wireless device can monitor traffic on the extension channel to facilitate accurate 20/40 MHz decision making. Protection, e.g. legacy preambles and RTS/CTS headers, can be provided on the control and extension channels.