OFDM transmission and reception for non-OFDM signals

• US 8,718,211 B2
• Filed: 06/06/2011
• Issued: 05/06/2014
• Est. Priority Date: 05/08/2007
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Hassan, Amer A., Huitema, Christian
• Primary Examiner(s): HA, DAC V
• Application Number:
  US13/153,801
• Publication Number:
  US 20110235732A1
• Time in Patent Office: 1,065 Days
• Field of Search: 375/260, 375/267, 375/285, 375/340, 375/346, 375/347, 375/349, 370/203, 370/208, 370/319, 370/344, 370/437, 370/441, 370/442, 370/464, 370/465, 370/480, 370/482, 370/487, 370/490
• US Class Current: 375/347
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/26524 Fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators in combination with other circuits for demodulation
• CPC Class Codes: H04L 69/12 Protocol engines
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Methods and apparatuses for Orthogonal Frequency-Division Multiplexing (OFDM) communication of non-OFDM radio signals are disclosed. The non-OFDM radio signals are force-modulated into OFDM signals. In one example, a non-OFDM signal is received and is processed into an OFDM signal to produce a created OFDM signal. An actual OFDM signal is also received and is processed together with the created OFDM signal.

Claims

1. At least one computer memory device storing computer-readable instructions that, when executed by a computing device, cause the computing device to perform actions for accommodating non-Orthogonal Frequency-Division Multiplexing signals (non-OFDM signals), the actions comprising:

a) receiving a non-OFDM signal;

b) processing the non-OFDM signal into a created OFDM signal;

c) processing the created OFDM signal;

d) transmitting OFDM and non-OFDM signals; and

e) processing the non-OFDM signals to transmit over a first set of sub-channels, processing the OFDM signals to transmit over a second set of sub-channels, and performing an Inverse Fast Fourier Transform (1FFT) of the signals.

2. The at least one computer memory device of claim 1, where the receiving the non-OFDM signal comprises receiving a wireless signal in a Bluetooth format.

3. The at least one computer memory device of claim 1, where the actions further comprise receiving the signals, combining the first and second sets of sub-channels and performing a Fast Fourier Transform (FFT) of the signals from the combined sets of sub-channels.

4. The at least one computer memory device of claim 1, where the actions further comprise receiving a second OFDM signal, the second OFDM signal being a wireless signal in a WiFi format.

5. The at least one computer memory device of claim 4, where the actions further comprise processing the received second OFDM signal using a Fast Fourier Transform (FFT).

6. The at least one computer memory device of claim 5, where the actions further comprise transmitting data from the received second OFDM signal through a serial to parallel converter to produce parallel data streams.

7. The at least one computer memory device of claim 6, the actions further comprising:

deciding bits of the data in the produced parallel data streams by a detector;

providing the decided bits of the data in the produced parallel data streams from the detector to a parallel to serial converter; and

outputting the decided bits from the parallel to serial converter in a serial stream.

8. At least one computer memory device storing computer-readable instructions that, when executed by a computing device, cause the computing device to perform actions for accommodating non-Orthogonal Frequency-Division Multiplexing signals (non-OFDM signals), the actions comprising:

a) receiving a non-OFDM signal by receiving a wireless signal in a Bluetooth format;

b) processing the non-OFDM signal into an OFDM signal to produce a created OFDM signal;

c) receiving an actual OFDM signal by receiving a wireless signal in a WiFi format; and

d) processing the actual OFDM signal with the created OFDM signal.

9. The at least one computer memory device of claim 8, where the processing the non-OFDM signal into an OFDM signal to produce a created OFDM signal comprises:

subdividing an information sequence from the non-OFDM signal into a plurality of frames;

generating a plurality of independent QAM sub-channels based on the plurality of frames;

multiplexing information from the plurality of independent QAM sub-channels into a serial stream of bits; and

converting digital symbols in the serial stream of bits to an analogue form.

10. The at least one computer memory device of claim 9, where the processing the actual OFDM signal with the created OFDM signal comprises:

receiving a transmitted signal including first information from the received actual OFDM signal and second information from the created OFDM signal;

converting the received transmitted signal from analog form to digital form;

subdividing the first information in the digital form from the received actual OFDM signal into a first plurality of parallel streams;

subdividing the second information from the received created OFDM signal into a second plurality of parallel streams;

performing a Fast Fourier Transform(FFT) on the first plurality of parallel streams and the second plurality of parallel streams to produce a first plurality of FFT-processed parallel streams and a second plurality of FFT-processed parallel streams; and

deciding bits of the first plurality of FFT-processed parallel streams and the second plurality of FFT-processed streams.

11. The at least one computer memory device of claim 10, where the performing an FFT on the first plurality of parallel streams and the second plurality of parallel streams to produce a first plurality of FFT-processed parallel streams and a second plurality of FFT-processed parallel streams comprises:

performing the FFT on the first plurality of parallel streams; and

performing the FFT on the second plurality of parallel streams separately from the performing the FFT on the first plurality of parallel streams.

12. The at least one computer memory device of claim 11, where:

a number of the first plurality of parallel streams is equal to a number of the second plurality of parallel streams, and

at least one of the second plurality of parallel streams is set to zero.

13. The at least one computer memory device of claim 11, where:

a number of the first plurality of parallel streams is different from a number of the second plurality of parallel streams.

14. At least one computer memory device storing computer-readable instructions that, when executed by a computing device, cause the computing device to perform actions for accommodating non-Orthogonal Frequency-Division Multiplexing signals (non-OFDM signals), the actions comprising:

a) receiving a non-OFDM signal;

b) processing the non-OFDM signal into an OFDM signal to produce a created OFDM signal;

c) receiving an actual OFDM signal;

d) processing the actual OFDM signal with the created OFDM signal;

e) transmitting OFDM and non-OFDM signals, processing the non-OFDM to transmit over a first set of sub-channels, processing the OFDM to transmit over a second set of sub-channels and performing an Inverse Fast Fourier Transform (IFFT) of the signals.

15. The at least one computer memory device of claim 14, where the actions are performed, at least in part, in software defined radio.

16. The at least one computer memory device of claim 14, where the actions further comprise adding a cyclic prefix before transmitting OFDM and non-OFDM signals.

17. The at least one computer memory device of claim 14, where the processing the non-OFDM signal into an OFDM signal to produce a created OFDM signal comprises:

subdividing an information sequence from the non-OFDM signal into a plurality of frames;

generating a plurality of parallel independent QAM sub-channels based on the plurality of frames;

multiplexing information from the plurality of parallel independent QAM sub-channels into a serial stream of bits; and

converting digital symbols in the serial stream of bits to an analogue form.

18. The at least one computer memory device of claim 17, where the actions further comprise adding a cyclic prefix to the plurality of parallel independent QAM sub-channels.

19. The at least one computer memory device of claim 17, where the actions further comprise up-converting the digital signals in the serial stream of bits in the analogue form to a radio frequency (RF) of interest.

20. The at least one computer memory device of claim 14, where the actions further comprise zeroing at least one sub-channel of the first set of sub-channels before transmitting the non-OFDM signal.