Efficient cyclic prefix generation with half tone offset
View Patent ↗Half tone offset may be utilized to mitigate signal distortion caused by DC bias within OFDM-based systems. In addition a cyclic prefix may be utilized within an OFDM-based system to mitigate inter-symbol-interference. Presented herein are techniques and methods to efficiently apply a cyclic prefix to an OFDM symbol with half tone offset for low power systems.
1. A cyclic prefix generation method for wireless communication comprising:
receiving a symbol waveform associated with one or more subcarriers, where each subcarrier of the one or more subcarriers is associated with a first frequency;
identifying a last portion of the symbol waveform;
modifying, by applying a half tone offset, a second frequency associated with the symbol waveform to generate a frequency shifted symbol waveform;
in response to generating the frequency shifted symbol waveform, inverting a sign of the last portion of the symbol waveform to generate an inverted portion;
prepending the inverted portion to the frequency shifted symbol waveform to generate an output signal; and
transmitting, to a receiving device, the output signal.
2. The cyclic prefix generation method for wireless communication of claim 1 , further comprising generating, based at least in part on an Inverse Fast Fourier Transform, the symbol waveform.
3. The cyclic prefix generation method for wireless communication of claim 1 , wherein the second frequency is a center frequency of the symbol waveform.
4. The cyclic prefix generation method for wireless communication of claim 1 , wherein the symbol waveform comprises a sample length of x and the last portion comprises a sample length of y, wherein x is a positive integer and y is a positive integer that is less than x.
5. The cyclic prefix generation method for wireless communication of claim 1 , wherein the output signal comprises a sample length of x and the inverted portion comprises a sample length y, wherein the inverted portion is prepended to a sample portion length of x and x is a positive integer and y is a positive integer that is less than x.
6. The cyclic prefix generation method for wireless communication of claim 1 , wherein the symbol waveform is an orthogonal frequency division multiplexing symbol waveform or a single carrier frequency divisional multiple access symbol waveform.
7. The cyclic prefix generation method for wireless communication of claim 1 , wherein the receiving device is a sensor within a narrow band Internet of Things system.
8. A non-transitory computer-readable storage medium having stored thereon instructions for causing at least one computer system to efficiently generate a cyclic prefix for wireless communication, the instructions comprising:
receiving a symbol waveform associated with one or more subcarriers, where each subcarrier of the one or more subcarriers is associated with a first frequency;
identifying a last portion of the symbol waveform;
modifying, by applying a half tone offset, a second frequency associated with the symbol waveform to generate a frequency shifted symbol waveform;
in response to generating the frequency shifted symbol waveform, inverting a sign of the last portion of the symbol waveform to generate an inverted portion;
prepending the inverted portion to the frequency shifted symbol waveform to generate an output signal; and
transmitting, to a receiving device, the output signal.
9. The computer-readable storage medium of claim 8 , the instructions further comprising generating, based at least in part on an Inverse Fast Fourier Transform, the symbol waveform.
10. The computer-readable storage medium of claim 8 , wherein the second frequency is a center frequency of the symbol waveform.
11. The computer-readable storage medium of claim 8 , wherein the symbol waveform comprises a sample length of x and the last portion comprises a sample length of y, wherein x is a positive integer and y is a positive integer that is less than x.
12. The computer-readable storage medium of claim 8 , wherein the output signal comprises a sample length of x and the inverted portion comprises a sample lengthy, wherein the inverted portion is prepended to a sample portion length of x and x is a positive integer and y is a positive integer that is less than x.
13. The computer-readable storage medium of claim 8 , wherein the symbol waveform is an orthogonal frequency division multiplexing symbol waveform or a single carrier frequency divisional multiple access symbol waveform.
14. The computer-readable storage medium of claim 8 , wherein the receiving device is a sensor within a narrow band Internet of Things system.
15. A system for efficiently generating a cyclic prefix for wireless communication, comprising:
one or more processors; and
a memory coupled with the one or more processors, the memory configured to store instructions that when executed by the one or more processors cause the one or more processors to:
receive a symbol waveform associated with one or more subcarriers, where each subcarrier of the one or more subcarriers is associated with a first frequency;
identify a last portion of the symbol waveform;
modify, by applying a half tone offset, a second frequency associated with the symbol waveform to generate a frequency shifted symbol waveform;
in response to generating the frequency shifted symbol waveform, invert a sign of the last portion of the symbol waveform to generate an inverted portion;
prepend the inverted portion to the frequency shifted symbol waveform to generate an output signal; and
transmit, to a receiving device, the output signal.
16. The system of claim 15 , wherein the instructions that when executed by the one or more processors further cause the one or more processors to generate, based at least in part on an Inverse Fast Fourier Transform, the symbol waveform.
17. The system of claim 15 , wherein the second frequency is a center frequency of the symbol waveform.
18. The system of claim 15 , wherein the symbol waveform comprises a sample length of x and the last portion comprises a sample length of less than 25 percent of x, wherein x is greater than or equal to 2048.
19. The system of claim 15 , wherein the output signal comprises a sample length of x and the inverted portion comprises a sample length of greater than 7 percent of x, wherein x is greater or equal to 2048.
20. The system of claim 15 , wherein the symbol waveform is an orthogonal frequency division multiplexing symbol waveform or a single carrier frequency divisional multiple access symbol waveform.