Method and apparatus for asynchronous OFDMA/SC-FDMA

• US 9,923,701 B2
• Filed: 12/04/2015
• Issued: 03/20/2018
• Est. Priority Date: 03/31/2014
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: Abdoli, Javad, Jia, Ming, Ma, Jianglei
• Primary Examiner(s): Wong, Warner
• Application Number:
  US14/960,167
• Publication Number:
  US 20160094329A1
• Time in Patent Office: 837 Days
• CPC Class Codes: H04L 27/2636 with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 27/265 Fourier transform demodulators, e.g. fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators H04L27/26524 takes precedence
• CPC Class Codes: H04L 27/26526 with inverse FFT [IFFT] or inverse DFT [IDFT] demodulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] receiver or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 5/005 of common pilots, i.e. pilots destined for multiple users or terminals
• CPC Class Codes: H04L 5/0066 Requirements on out-of-channel emissions
• CPC Class Codes: H04L 7/06 the synchronisation signals differing from the information signals in amplitude, polarity or frequency or length
• CPC Class Codes: H04W 72/0446 Resources in time domain, e.g. slots or frames

Abstract

Various disclosed embodiments include methods and systems for communication in a wireless communication system. A method comprises receiving a signal corresponding to a plurality of modulated signals, each of the plurality of modulated signals corresponding to a unique electronic device. The method comprises filtering the received signal with a plurality of filters, each of which is matched to a corresponding filter in a respective electronic device to obtain a filtered signal for the respective electronic device. The method comprises performing a fast Fourier transform (FFT) operation on the filtered signal to obtain demodulated data corresponding to the respective electronic device.

Claims

1. A method of transmitting data, the method comprising:

receiving, by a receiver, a first Orthogonal Frequency Division Multiplexing (OFDM) modulated signal from a first wireless electronic device over a first plurality of subcarriers; and

receiving, by the receiver, a second OFDM modulated signal from a second wireless electronic device over a second plurality of subcarriers, wherein main lobes of the first OFDM modulated signal and the second OFDM modulated signal have bandwidths in the frequency domain that are equal to respective bandwidths associated with the first plurality of subcarriers and the second plurality of subcarriers, and wherein side lobes of the first OFDM modulated signal and the second OFDM modulated signal have amplitudes below a threshold outside the respective bandwidths of the first plurality of subcarriers and the second plurality of subcarriers.

2. The method of claim 1, further comprising receiving a resource assignment from a scheduler.

3. The method of claim 1, wherein the first OFDM modulated signal and the second OFDM modulated signal are Cyclic Prefix OFDM (CP-OFDM) signals.

4. The method of claim 1, wherein a transmission of the first OFDM modulated signal is asynchronous with a transmission of the second OFDM modulated signal.

5. A receiver comprising:

a processor; and

a non-transitory computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

receive a first Orthogonal Frequency Division Multiplexing (OFDM) modulated signal from a first wireless electronic device over a first plurality of subcarriers; and

receive a second OFDM modulated signal from a second wireless electronic device over a second plurality of subcarriers, wherein main lobes of the first OFDM modulated signal and the second OFDM modulated signal have bandwidths in the frequency domain that are equal to respective bandwidths associated with the first plurality of subcarriers and the second plurality of subcarriers, and wherein side lobes of the first OFDM modulated signal and the second OFDM modulated signal have amplitudes below a threshold outside the respective bandwidths of the first plurality of subcarriers and the second plurality of subcarriers.

6. The receiver of claim 5, wherein a transmission of the first OFDM modulated signal is asynchronous with a transmission of the second OFDM modulated signal.

7. The receiver of claim 5, wherein the programming further includes instructions to receive a resource assignment from a scheduler.

8. The receiver of claim 5, wherein the first OFDM modulated signal and the second OFDM modulated signal are filtered Cyclic Prefix OFDM (CP-OFDM) signals.

9. A method of transmitting data, the method comprising;

transmitting, by a first wireless electronic device, a first Orthogonal Frequency Division Multiplexing (OFDM) modulated signal over a first plurality of subcarriers, a second OFDM modulated signal having been transmitted over a second plurality of subcarriers by a second wireless electronic device, wherein main lobes of the first OFDM modulated signal and the second OFDM modulated signal have bandwidths in the frequency domain that are equal to respective bandwidths associated with the first plurality of subcarriers and the second plurality of subcarriers, and side lobes with amplitudes below a threshold outside the respective bandwidths of the first plurality of subcarriers and the second plurality of subcarriers.

10. The method of claim 9, wherein the first OFDM modulated signal is transmitted asynchronously with the second OFDM modulated signal.

11. The method of claim 9, wherein the first OFDM modulated signal and the second OFDM modulated signal are filtered Cyclic Prefix OFDM (CP-OFDM) signals.

12. The method of claim 9, wherein the first OFDM modulated signal is generated by applying an Inverse Fast Fourier Transform (IFFT) to data.

13. The method of claim 9, further comprising:

filtering the first OFDM modulated signal to attenuate the amplitude of the side lobes of the first OFDM modulated signal below the threshold prior to transmitting the first OFDM modulated signal over the first plurality of subcarriers.

14. The method of claim 13, wherein filtering the first OFDM modulated signal comprises localizing the first OFDM modulated signal in the frequency domain.

15. The method of claim 13, wherein filtering the first OFDM modulated signal includes applying a spectrum shaping filter to the first OFDM modulated signal.

16. The method of claim 15, wherein the spectrum shaping filter is a Finite Impulse Response (FIR) filter.

17. The method of claim 9, wherein transmitting the first OFDM modulated signal includes transmitting the first OFDM modulated signal over the first plurality of subcarriers without synchronizing transmission of the first OFDM modulated signal with the second OFDM modulated signal.

18. The method of claim 9, wherein transmitting the first OFDM modulated signal comprises transmitting the first OFDM modulated signal to a receiver indicated by a scheduler.

19. The method of claim 18, wherein transmitting the first OFDM modulated signal comprises transmitting the first OFDM modulated signal without regard to synchronization information from the scheduler.

20. A first wireless electronic device comprising:

a processor; and

a non-transitory computer readable storage medium storing programming for execution by the processor, the programming including instructions to;

transmit a first Orthogonal Frequency Division Multiplexing (OFDM) modulated signal over a first plurality of subcarriers, a second OFDM modulated signal having been transmitted over a second plurality of subcarriers by a second wireless electronic device, wherein main lobes of the first OFDM modulated signal and the second OFDM modulated signal have bandwidths in the frequency domain that are equal to respective bandwidths associated with the first plurality of subcarriers and the second plurality of subcarriers, and side lobes with amplitudes below a threshold outside the respective bandwidths of the first plurality of subcarriers and the second plurality of subcarriers.

21. The first wireless electronic device of claim 20, wherein the first OFDM modulated signal is transmitted asynchronously with the second OFDM modulated signal.

22. The first wireless electronic device of claim 20, wherein the first OFDM modulated signal and the second OFDM modulated signal are filtered Cyclic Prefix OFDM (CP-OFDM) signals.

23. The first wireless electronic device of claim 20, wherein the first OFDM modulated signal is generated by applying an Inverse Fast Fourier Transform (IFFT) to data.

24. The first wireless electronic device of claim 20, wherein the programming further includes instructions to:

filter the first OFDM modulated signal to attenuate the amplitude of the side lobes of the first OFDM modulated signal below the threshold prior to transmitting the first OFDM modulated signal over the first plurality of subcarriers.

25. The first wireless electronic device of claim 24, wherein the instructions to filter the first OFDM modulated signal include instructions to localize the first OFDM modulated signal in the frequency domain.

26. The first wireless electronic device of claim 24, wherein the instructions to filter the first OFDM modulated signal include instructions to apply a spectrum shaping filter to the first OFDM modulated signal.

27. The first wireless electronic device of claim 26, wherein the spectrum shaping filter is a Finite Impulse Response (FIR) filter.

28. The first wireless electronic device of claim 20, wherein the instructions to transmit the first OFDM modulated signal includes instructions to transmit the first OFDM modulated signal over the first plurality of subcarriers without synchronizing the first OFDM modulated signal with the second OFDM modulated signal.

29. The first wireless electronic device of claim 20, wherein the instructions to transmit the first OFDM modulated signal include instructions to transmit the first OFDM modulated signal to a receiver indicated by a scheduler.

30. The first wireless electronic device of claim 29, wherein the instructions to transmit the first OFDM modulated signal include instructions to transmit the first OFDM modulated signal without regard to synchronization information from the scheduler.