Preamble generator for a multiband OFDM transceiver
View Patent ↗Preamble generator for a multiband frequency division multplexing (OFDM) tranceiver of a wireless personal area network (WPAN) being switchable between a time frequency interleaving (TFI)-mode wherein data packets are transmitted by said transceiver in different frequency bands according to a predetermined frequency hopping pattern and a fixed frequency interleaving (FFI) mode wherein data packets are transmitted by the transceiver in at least one fixed frequency band, wherein said preamble generator scrambles in the fixed frequency interleaving (FFI) mode a predetermined preamble of the data packets by multiplying said preamble with a pseudo random data sequence to flatten a power spectrum of said preamble.
1. 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.
2. The transceiver of claim 1 , wherein the preamble generator is operable to generate the scrambled preamble by multiplying the predetermined preamble with a binary pseudo random data sequence.
3. The transceiver of claim 2 , wherein:
the preamble generator is operable to generate the scrambled preamble by multiplying a predetermined preamble comprising a predetermined number of orthogonal frequency division multiplexed symbols with the binary pseudo random data sequence;
the binary pseudo random data sequence comprises a predetermined number of binary data values; and
the number of predetermined orthogonal frequency division multiplexed symbols corresponds to the number of predetermined binary data values.
4. The transceiver of claim 3 , wherein the stored at least one long pseudo random data sequence comprises the following sequence: −1, −1, −1, −1, −1, −1, −1, 1, −1, −1, 1, −1, −1, 1, −1, −1, 1, −1, −1, 1, −1, 1, 1, 1.
5. The transceiver of claim 3 , wherein the stored at least one long pseudo random data sequence comprises first predetermined sequence of twenty-four data.
6. The transceiver of claim 1 , wherein the preamble generator is operable to generate a scrambled preamble by multiplying a predetermined preamble comprising a predetermined number of orthogonal frequency division multiplexed symbols with a pseudo random data sequence.
7. The transceiver of claim 6 , wherein each of the predetermined number of orthogonal frequency division multiplexed symbols comprises a sequence of data samples.
8. The transceiver of claim 7 , wherein each of the predetermined number of orthogonal frequency division multiplexed symbols comprises 128 data samples.
9. The transceiver of claim 1 , wherein the preamble generator is operable to generate a scrambled preamble by multiplying the at least one stored preamble with the selected one of the stored at least one long pseudo random data sequence and the stored at least one short pseudo random data sequence in a Kronecker product.
10. The transceiver of claim 1 , wherein the stored at least one long pseudo random data sequence comprises the following sequence: −1, −1, −1, −1, −1, −1, −1, 1, −1, −1, 1, −1, −1, 1, −1, −1, 1, −1, −1, 1, −1, 1, 1, 1.
11. The transceiver of claim 1 , wherein the stored at least one long pseudo random data sequence comprises first predetermined sequence of twenty-four data.
12. 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, the preamble generator comprising
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, and
a calculation unit operable to generate a scrambled preamble by multiplying the stored at least one predetermined preamble with a selected one of the stored at least one long pseudo random data sequence and a subset of the stored at least one long pseudo random data sequence; and wherein
the stored at least one long pseudo random data sequence comprises a first predetermined sequence of twenty-four data; and
the subset of the stored at least one long pseudo random data sequence consists of the last twelve data of the first predetermined sequence of twenty-four data.
13. The transceiver of claim 12 , wherein the stored at least one long pseudo random data sequence comprises the following sequence: −1, −1, −1, −1, −1, −1, −1, 1, −1, −1, 1, −1, −1, 1, −1, −1, 1, −1, −1, 1, −1, 1, 1, 1.
14. The transceiver of claim 12 wherein the subset of the stored at least one long pseudo random data sequence comprises the following sequence: −1, 1, −1, −1, 1, −1, −1, 1, −1, 1, 1, 1.
15. The transceiver of claim 14 , wherein the calculation unit is operable to generate a scrambled preamble by multiplying the at least one stored preamble with the selected one of the stored at least one long pseudo random data sequence and the subset of the stored at least one long pseudo random data sequence in a Kronecker product.
16. The transceiver of claim 12 , wherein the calculation unit is operable to generate a scrambled preamble by multiplying the at least one stored preamble with the selected one of the stored at least one long pseudo random data sequence and the subset of the stored at least one long pseudo random data sequence in a Kronecker product.