IP Library Granted Patent US 6,888,790
Granted Patent B2
US 6,888,790 · App. 10/017,607 · Granted May 3, 2005

Frame synchronization technique for OFDM based modulation scheme

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Quick Facts
Patent No.
US 6,888,790
App. No.
10/017,607
Granted
May 3, 2005
Kind
B2
Abstract

The present invention relates to the field of communications. The method includes generating a sequence of symbols, the sequence of symbols including preamble symbols and a data symbol. The method further includes receiving the sequence of symbols generated by the transmitter, the receiver including a frame synchronizer logic to perform frame synchronization.

Claims (22)

1. A system comprising:

a transmitter in a first network node to generate a sequence of symbols, the sequence of including preamble symbols and a data symbol, a last preamble symbol in the sequence of symbols having a different waveform than other preamble symbols in the sequence of symbols; and

a receiver in a second network node to receive the sequence of symbols generated by the transmitter, the receiver including a frame synchronizer logic to perform frame synchronization.

2. A system comprising:

a transmitter in a first network node to generate a sequence of symbols, the sequence of including preamble symbols and a data symbol, a waveform of a last preamble symbol in the sequence of symbols is different than waveforms of other preamble symbols in the sequence of symbols; and

a receiver in a second network node to receive the sequence of symbols generated by the transmitter, the receiver including a frame synchronizer logic to perform frame synchronization.

3. The system of claim 2 , wherein the difference between the waveform of the last preamble and the waveforms of other preamble symbols provide a way for the frame synchronizer logic to detect the last preamble symbol.

4. The system of claim 2 , wherein the last preamble symbol immediately precedes the data symbol and the frame synchronizer logic detects the data symbol by detecting the last preamble symbol.

5. The system of claim 2 , wherein the frame synchronizer logic obtains the data symbol by taking a Fast Fourier Transform (FFT) of the preamble symbols, conjugating FFT coefficients, and taking an inverse FFT.

6. The system of claim 2 , wherein the frame synchronizer logic obtains the data symbol by adding a constant to each carrier phase of the preamble symbols.

7. A method comprising:

generating a sequence of symbols, the sequence of symbols including preamble symbols and data symbol;

using a second waveform to represent a last preamble symbol in the sequence of symbols and a first waveform to represent other preamble symbols in the sequence of symbols, wherein the second waveform is substantially different than the first waveform; and

receiving the sequence of symbols generated by the transmitter, the receiver including a frame synchronizer logic to perform frame synchronization.

8. The method of claim 7 , further comprising:

detecting the last preamble symbol in the sequence of symbols by recognizing the substantial difference between the second waveform and the first waveform.

9. The method of claim 7 , further comprising placing the last preamble immediately before the data symbol.

10. The method of claim 7 , further comprising detecting the data symbol by recognizing the last preamble symbol.

11. The method of claim 7 , further comprising obtaining the data symbol by adding a constant to each carrier phase of the preamble symbols.

12. A machine-readable medium comprising instructions which, when executed by a machine, cause the machine to perform operations comprising:

generating a sequence of symbols, the sequence of symbols including preamble symbols and a data symbol, a last preamble symbol in the sequence of symbols having a different waveform than other preamble symbols in the sequence of symbols; and

receiving the sequence of symbols generated by the transmitter, the receiver including a frame synchronizer logic to perform frame synchronization.