Pulse shaping for multicarrier modulation
Pulse shaping for multicarrier modulation
 CN 1,158,825 C
 Filed: 07/03/1996
 Issued: 07/21/2004
 Est. Priority Date: 07/14/1995
 Status: Active Grant
First Claim
1. method that sends data on the communication channel of a communication system, the communication in described communication system between the transmitter and receiver is f by a carrier frequency _{c}System carrier on communication channel on one group of subcarrier, carry out, described method comprises step:
 Utilize inverseFourier transform IFFT circuit that in one group of data symbol each is modulated in one group of subcarrier one, to produce one group of modulated subcarriers, described data symbol comprises that each has a plurality of symbol C of symbol period T _{k}, k=0 ..., N '"'"'1, described modulated subcarriers comprises one first datasignal;
Make described first datasignal and a pulse shaping waveform multiply each other, to produce one second datasignal, described pulse shaping waveform comprises the function that has one first and second amplitude at least, and wherein said first amplitude is greater than described second amplitude;
And the utilization frequency relevant with employed certain pulses shaping function adjust coefficient and remove to adjust selected subcarrier, to keep the orthogonality in the data transmission procedure;
On described system carrier, send described second datasignal.
Chinese PRB Reexamination
Abstract
A method and system for data transmission in an orthogonal frequency division multiplexed (OFDM) system is provided. In the invention each of a plurality of data symbols Ck, having a symbol period T, are modulated (404) onto one of a plurality of subcarriers comprising a first data signal. The first data signal is then multiplied (406) by a pulseshaping function over the period T to generate a second data signal. The second data signal is then modulated (412) and transmitted on a system carrier over a communications channel (414) of the OFDM system.
27 Claims

1. method that sends data on the communication channel of a communication system, the communication in described communication system between the transmitter and receiver is f by a carrier frequency _{c}System carrier on communication channel on one group of subcarrier, carry out, described method comprises step:

Utilize inverseFourier transform IFFT circuit that in one group of data symbol each is modulated in one group of subcarrier one, to produce one group of modulated subcarriers, described data symbol comprises that each has a plurality of symbol C of symbol period T _{k}, k=0 ..., N '"'"'1, described modulated subcarriers comprises one first datasignal;
Make described first datasignal and a pulse shaping waveform multiply each other, to produce one second datasignal, described pulse shaping waveform comprises the function that has one first and second amplitude at least, and wherein said first amplitude is greater than described second amplitude;
And the utilization frequency relevant with employed certain pulses shaping function adjust coefficient and remove to adjust selected subcarrier, to keep the orthogonality in the data transmission procedure;On described system carrier, send described second datasignal.


2. the method for claim 1 is characterized in that, described modulation step comprises:
One group of data symbol C with symbol period T _{K}In each be modulated to and have frequency f _{k}, k=0 ..., on the subcarrier of N '"'"'1, wherein, f _{k}=f _{c}+ α
k/T, α
comprise an adjustment coefficient greater than 1 constant, and described modulated subcarriers comprises described first datasignal.

3. the method for claim 2 is characterized in that, also comprises step:

Receive one the 3rd datasignal y (t) in receiver, described the 3rd datasignal is included in described second datasignal after the transmission on the described system carrier;
AndIn described receiver, detect described data symbol set C _{K}, k=0 ..., N '"'"'1.


4. the method for claim 2 is characterized in that, wherein said pulse shaping waveform comprises a raised cosine pulse with predetermined rollofffactor.

5. the method for claim 4 is characterized in that, wherein said pulse shaping waveform comprises a Hanning function.

6. the method for claim 1 is characterized in that, wherein said modulation step comprises:
One group of data symbol is carried out N '"'"' some inverse fast fourier transformed IFFT one time, to produce described first datasignal.

7. the method for claim 6 is characterized in that, the wherein said step that multiplies each other comprises:

To the continuation that circulates of described first datasignal, to produce the datasignal after the continuation;
AndMake datasignal and a time discrete pulse shaping function after the described continuation multiply each other, to produce described second datasignal.


8. the method for claim 7 is characterized in that, also comprises step:

Receive one the 3rd datasignal in receiver, described the 3rd datasignal is included in described second datasignal after the transmission on the described communication channel; Described the 3rd datasignal is made up, to produce the 4th datasignal;
AndDescribed the 4th datasignal is carried out a N '"'"' point fast Fourier conversion (FFT), to produce described data symbol set.


9. the method for claim 7 is characterized in that, wherein said pulse shaping function comprises a time discrete raised cosine with predetermined rollofffactor.

10. the method for claim 9 is characterized in that, wherein said pulse shaping function comprises a time discrete Hanning function.

11. the method for claim 1 is characterized in that, described coefficient carrier frequency is f _{c}, described modulation step comprises:
Described data symbol is carried out N '"'"' some inverse fast fourier transformed (IFFT), and to produce first datasignal, described first datasignal comprises a signal z _{n}, it is made up of the individual time discrete value of N '"'"', and each described time discrete value is corresponding frequency f in frequency domain _{k}, k=0 ..., N '"'"'1, wherein, f _{k}=f _{c}+ α
k/T, α
are the adjustment coefficients that comprises greater than 1 constant.

12. the method for claim 11 is characterized in that, the wherein said step that multiplies each other comprises:

On described symbol period T to the described first datasignal z _{n}The continuation that circulates is to produce the datasignal a that comprises N time discrete value after the continuation _{n}And Datasignal a after making described continuation on the described period T _{n}With a time discrete pulse shaping function w _{n}=w _{0}, w _{1}..., w _{N1}Multiply each other, to produce the described second datasignal x _{n}=w _{n}a _{n}, n=0 ... N1, described pulse shaping function has one first amplitude w _{N1}With one second amplitude w _{N2}, wherein said first amplitude is greater than described second amplitude.


13. the method for claim 12 is characterized in that, also comprises step:

In receiver, receive one the 3rd datasignal b _{n}, described the 3rd datasignal is included in the described second datasignal x after the transmission on the described communication channel _{n} On described symbol period T to described the 3rd datasignal b _{n}Make up, comprise the 4th datasignal y of the individual time discrete value of N '"'"' with generation _{n}And To described the 4th datasignal y _{n}Carry out a N '"'"' point fast Fourier conversion (FFT), to produce described data symbol set C _{K}, k=0 ..., N '"'"'1.


14. the method for claim 12 is characterized in that, wherein said pulse shaping function w _{n}Comprise a time discrete raised cosine with predetermined rollofffactor.

15. the method for claim 14 is characterized in that, wherein said pulse shaping function w _{n}Comprise a time discrete Hanning function.

16. be used to send the device of data in a communication system, wherein the communication between the transmitter and receiver is by a carrier frequency position f _{c}System carrier on communication channel on one group of subcarrier, carry out, described device comprises:

Be used for to one group each have the data symbol C of symbol period T _{K}, k=0 ..., N '"'"'1 carries out IFFT and produces the inverse fast fourier transformed IFFT circuit of one first datasignal;
A multiplier is used for described first datasignal and a pulse shaping function that has in the time domain of at least one first and second amplitude are multiplied each other, and wherein said first amplitude is greater than described second amplitude, to produce one second datasignal; A frequency relevant with used specific shaping function is adjusted coefficient, is used to adjust selected subcarrier, so that keep the orthogonality in the data transmission procedure; On described communication channel, send the transmitter of described second datasignal.


17. the device of claim 16 is characterized in that, wherein said multiplier comprises:

To the continuation that circulates of described first datasignal, to produce the circulation continuation circuit of a continuation signal;
AndMake a pulse shaping function in described continuation signal and the time domain multiply each other, to produce the multiplier of described second datasignal.


18. the device of claim 16 is characterized in that, wherein said this group data symbol comprises first group of data symbol, and described device also comprises:
A serial digital data stream is converted to the serialparallel converter of described first data symbol.

19. the device of claim 16 is characterized in that, wherein said first datasignal comprises a signal z who comprises the individual time discrete value of N '"'"' _{n}, each described time discrete value is corresponding frequency f in frequency domain _{k}, k=0 ..., N '"'"'1, wherein, f _{k}=f _{c}+ α
 k/T, α
comprise greater than the frequency of 1 constant adjusting coefficient.
 k/T, α

20. the device of claim 19 is characterized in that, wherein said multiplier comprises:

To the described first datasignal z _{n}The continuation that circulates is to produce the signal a that comprises N discrete time value after the continuation _{n}Circulation continuation circuit;
AndOn described period T, make described continuation signal a _{n}Multiply each other with a pulse shaping function in the time domain, to produce the multiplier of described second datasignal.


21. the device of claim 20 is characterized in that, wherein said multiplier comprises that makes a described continuation signal a on described period T _{n}With a pulse shaping function w _{n}=w _{0}, w _{1}..., w _{N1}Multiply each other, to produce the multiplier of described second datasignal, described second datasignal comprises a signal x _{n}=w _{n}a _{n}, n=0 ... N1, described pulse shaping function has one first amplitude w at least _{N1}With the second amplitude w _{N2}, wherein said first amplitude is greater than described second amplitude.

22. the device of claim 21 is characterized in that, wherein said multiplier comprises one group of multiplier, and each described multiplier is used to make a value a of described continuation signal _{n}Thresholding w when corresponding _{n}Multiply each other, to produce described second datasignal.

23. the device of claim 21 is characterized in that, wherein said pulse shaping function comprises a time discrete raised cosine pulse.

24. the device of claim 23 is characterized in that, wherein said pulse shaping function comprises a Hanning function.

25. be used to receive the device of data in a communication system, wherein the communication between the transmitter and receiver is f by a frequency _{c}System carrier on communication channel on one group of subcarrier, carry out, described device comprises:

Be used to be received in first datasignal that transmits on the described communication channel, and second a datasignal b who comprises N discrete time value is provided _{n}Receiver;
To the described second datasignal b _{n}Make up, to produce a composite signal y who comprises N discrete time value _{n}Combination device circuit;
AndTo described composite signal y _{n}Carry out a FFT and produce one group of data symbol C _{k}The fast Fourier transform (FFT) circuit, k=0 ..., N '"'"'1, each y _{n}The time discrete value in described FFT with a frequency f _{k}=f _{c}+ α
k/T is associated, and α
is the constant greater than 1.


26. the device of claim 25 is characterized in that, wherein said receiver comprises a serialparallel converter that receives the receiver of described first datasignal and described first datasignal is converted to described second datasignal.

27. the device of claim 25 is characterized in that, also comprises a parallel to serial converter that described this group data symbol is converted to serial data.
Specification(s)