Patent ID: 7411898

Claim:
A multiband frequency division multiplexing transceiver switchable between a time frequency interleaving mode and a fixed frequency interleaving mode, said multiband frequency division multiplexing transceiver comprising: a preamble generator operable to generate a scrambled preamble by multiplying a predetermined preamble of a data packet to be transmitted in fixed frequency interleaving mode with a pseudo random data sequence, such that when the preamble is transmitted in fixed frequency interleaving mode, the power spectrum of the transmitted scrambled preamble is flattened with respect to the power spectrum realized when transmitting the predetermined preamble without scrambling, wherein the preamble generator comprises a first memory operable to store at least one predetermined preamble, a second memory operable to store at least one long pseudo random data sequence, a third memory operable to store at least one short pseudo random data sequence. a first selection unit operably connected to the first memory to select one of the stored at least one predetermined preamble in response to a channel selection signal, a second selection unit operably connected to the second memory to select one of the stored at least one long pseudo random data sequence in response to the channel selection signal, a third selection unit operably connected to the third memory to select one of the stored at least one short pseudo random data sequence in response to the channel selection signal, and a fourth selection unit operably connected to the second selection unit and the third selection unit to select one of the selected one of the stored at least one long pseudo random data sequence and the selected one of the stored at least one short pseudo random data sequence in response to a preamble selection signal.