Dynamic Configuration of a Flexible Orthogonal Frequency Division Multiplexing PHY Transport Data Frame

• US 20170054581A1
• Filed: 07/28/2016
• Published: 02/23/2017
• Est. Priority Date: 08/07/2014
• Status: Active Grant

• Current Assignee: One Media LLC (Sinclair, Inc.)
• Original Assignee: One Media LLC (Sinclair, Inc.)
• Inventors: SIMON, Michael J., Shelby, Kevin A., Earnshaw, Mark
• Granted Patent: US 9,853,851 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H04L 27/26025 Numerology, i.e. varying one or more of symbol duration, subcarrier spacing, Fourier transform size, sampling rate or down-clocking allocating sub-channels of the transmission path H04L5/003
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/003 Arrangements for allocating sub-channels of the transmission path
• CPC Class Codes: H04W 72/30 Resource management for broadcast services
• CPC Class Codes: H04W 88/16 Gateway arrangements

Abstract

A base station may generate and transmit a transport stream including a sequence of frames. A frame may include a plurality of partitions, where each partition includes a corresponding set of OFDM symbols. For each partition, the OFDM symbols in that partition may have a corresponding cyclic prefix size and a corresponding FFT size, allowing different partitions to be targeted for different collections of user devices, e.g., user devices having different expected values of maximum delay spread and/or different ranges of mobility. The base station may also dynamically re-configure the sample rate of each frame, allowing further resolution in control of subcarrier spacing. By allowing the cyclic prefixes of different OFDM symbols to have different lengths, it is feasible to construct a frame that conforms to a set payload duration and has arbitrary values of cyclic prefix size per partition and FFT size per partition. The partitions may be multiplexed in time and/or frequency.

Claims

1. An apparatus, comprising:

a processor configured to generate a data frame; and

a transmitter configured to wirelessly broadcast the data frame,

wherein the data frame comprises a first set of orthogonal frequency domain multiplexing (OFDM) symbols and a second set of OFDM symbols, each OFDM symbol in the first set of OFDM symbols and the second set of OFDM symbols comprising a useful portion and a cyclic prefix,

wherein, to generate said each OFDM symbol, the processor is further configured to;

convert a block of frequency domain data to time-domain samples using an inverse fast Fourier transform having a transform size to form the useful portion; and

form the cyclic prefix by prepending to said each OFDM symbol a plurality of time-domain samples from the end of the useful portion,

wherein the processor is further configured to form the first set of OFDM symbols using a first transform size and a first cyclic prefix size, and to form the second set of OFDM symbols using a second transform size and a second cyclic prefix size, and

wherein the data frame further comprises a plurality of parameters separately indicating the first cyclic prefix size, the second cyclic prefix size, the first transform size, and the second transform size.

2. The apparatus of claim 1, wherein the first cyclic prefix size is different than the second cyclic prefix size.

3. The apparatus of claim 2, wherein the first transform size is different than the second transform size.

4. The apparatus of claim 1, wherein the first transform size is different than the second transform size.

5. The apparatus of claim 1, wherein the first transform size and the second transform size are each selected from the group consisting of:

8192, 16384, and 32768.

6. The apparatus of claim 1, wherein the first cyclic prefix size and the second cyclic prefix size are each selected from the group consisting of:

192, 384, 512, 768, 1024, 1536, 2048, 3072, and 4096 samples.

7. The apparatus of claim 1, wherein the frequency domain data comprises a set of useful subcarriers and a set of non-useful subcarriers.

8. The apparatus of claim 7, wherein the data frame further comprises a second plurality of parameters separately indicating the number of useful subcarriers in the first set of OFDM symbols and the number of useful subcarriers in the second set of OFDM symbols.

9. A method, comprising:

generating a data frame; and

wirelessly broadcasting the data frame,

wherein generating the data frame comprises;

generating a first set of orthogonal frequency domain multiplexing (OFDM) symbols; and

generating a second set of OFDM symbols,

wherein each OFDM symbol of the first set of OFDM symbols and the second set of OFDM symbols comprises a useful portion and a cyclic prefix,

wherein generating said each OFDM symbol comprises;

converting a block of frequency domain data to time-domain samples using an inverse fast Fourier transform having a transform size to form the useful portion; and

forming the cyclic prefix by prepending to said each OFDM symbol a plurality of time-domain samples from the end of the useful portion of the OFDM symbol,

wherein generating the data frame further comprises;

forming the first set of OFDM symbols using a first transform size and a first cyclic prefix size; and

forming the second set of OFDM symbols using a second transform size and a second cyclic prefix size, and

wherein the data frame comprises a plurality of parameters separately indicating the first cyclic prefix size, the second cyclic prefix size, the first transform size, and the second transform size.

10. The method of claim 9, wherein the first cyclic prefix size is different than the second cyclic prefix size.

11. The method of claim 10, wherein the first transform size is different than the second transform size.

12. The method of claim 9, wherein the first transform size is different than the second transform size.

13. The method of claim 9, wherein the first transform size and the second transform size are each selected from the group consisting of:

8192, 16384, and 32768.

14. The method of claim 9, wherein the first cyclic prefix size and the second cyclic prefix size are each selected from the group consisting of:

192, 384, 512, 768, 1024, 1536, 2048, 3072, and 4096 samples.

15. The method of claim 9, wherein the frequency domain data comprises a set of useful subcarriers and a set of non-useful subcarriers.

16. The method of claim 15, wherein the data frame further comprises a second plurality of parameters separately indicating the number of useful subcarriers in the first set of OFDM symbols and the number of useful subcarriers in the second set of OFDM symbols.

17. An apparatus, comprising:

a receiver configured to wirelessly receive a data frame; and

a processor configured to decode the data frame,

wherein the processor is further configured to;

decode a plurality of parameters for a first set of orthogonal frequency division multiplexing (OFDM) symbols and a second set of OFDM symbols of the data frame;

decode, based at least on a first parameter in the plurality of parameters, the first set of OFDM symbols using a first transform size; and

decode, based at least on a second parameter in the plurality of parameters, the second set of OFDM symbols using a second transform size,

wherein each OFDM symbol in the first set of OFDM symbols comprises a first useful portion and a first cyclic prefix having a first cyclic prefix size, and each OFDM symbol in the second set of OFDM symbols comprises a second useful portion and a second cyclic prefix having a second cyclic prefix size, and

wherein the processor is further configured to convert a useful portion of a selected OFDM symbol to a block of frequency domain data using a fast Fourier transform to form frequency domain data.

18. The apparatus of claim 17, wherein the first cyclic prefix size is different than the second cyclic prefix size.

19. The apparatus of claim 18, wherein the first transform size is different than the second transform size.

20. The apparatus of claim 17, wherein the first transform size is different than the second transform size.

21. An apparatus, comprising:

a processor configured to generate a data frame including a non-payload region and a payload region; and

a transmitter configured to wirelessly broadcast the data frame,

wherein the payload region of the data frame comprises a first set of orthogonal frequency domain multiplexing (OFDM) symbols and a second set of OFDM symbols, each OFDM symbol in the first set of OFDM symbols and the second set of OFDM symbols comprising a useful portion and a cyclic prefix,

wherein the processor is further configured to form the first set of OFDM symbols using a first transform size and a first cyclic prefix size, and to form the second set of OFDM symbols using a second transform size and a second cyclic prefix size,

wherein the first cyclic prefix size is a sum of a first base cyclic prefix size and an extension size, and

wherein the second cyclic prefix size is a sum of a second base cyclic prefix size and the extension size.

22. The apparatus of claim 21, wherein to generate said each OFDM symbol, the processor is further configured to:

convert a block of frequency domain data to time-domain samples using an inverse fast Fourier transform having a transform size to form the useful portion; and

form the cyclic prefix by prepending to said each OFDM symbol a plurality of time-domain samples from the end of the useful portion;

23. The apparatus of claim 21, wherein the processor is further configured to:

determine a number of excess samples based at least on a difference between a total number of samples in the payload region and a sum of a total number of samples in the first set of OFDM symbols and a total number of samples in the second set of OFDM symbols; and

determine the extension size based on at least a ratio between the number of excess samples and a sum of a total number of OFDM symbols in the first set of OFDM symbols and a total number of OFDM symbols in the second set of OFDM symbols.

24. The apparatus of claim 21, wherein the first cyclic prefix size is different than the second cyclic prefix size.

25. The apparatus of claim 21, wherein the first transform size is different than the second transform size.

26. The apparatus of claim 21, wherein the first transform size and the second transform size are each selected from the group consisting of:

8192, 16384, and 32768.

27. The apparatus of claim 21, wherein the first cyclic prefix size and the second cyclic prefix size are each selected from the group consisting of:

192, 384, 512, 768, 1024, 1536, 2048, 3072, and 4096 samples.

28. A method, comprising:

generating data frame including a non-payload region and a payload region; and

wirelessly broadcasting the data frame,

wherein the payload region of the data frame comprises a first set of orthogonal frequency domain multiplexing (OFDM) symbols and a second set of OFDM symbols, each OFDM symbol in the first set of OFDM symbols and the second set of OFDM symbols comprising a useful portion and a cyclic prefix,

wherein generating the data frame comprises;

forming the first set of OFDM symbols using a first transform size and a first cyclic prefix size, and

forming the second set of OFDM symbols using a second transform size and a second cyclic prefix size,

wherein the first cyclic prefix size is a sum of a first base cyclic prefix size and an extension size, and

wherein the second cyclic prefix size is a sum of a second base cyclic prefix size and the extension size.

29. The method of claim 28, further comprising:

determining a number of excess samples based at least on a difference between a total number of samples in the payload region and a sum of a total number of samples in the first set of OFDM symbols and a total number of samples in the second set of OFDM symbols; and

determining the extension size based on at least a ratio between the number of excess samples and a sum of a total number of OFDM symbols in the first set of OFDM symbols and a total number of OFDM symbols in the second set of OFDM symbols.

30. The method of claim 28, wherein the first cyclic prefix size is different than the second cyclic prefix size.

31. The method of claim 28, wherein the first transform size is different than the second transform size.

32. The method of claim 28, wherein the first transform size and the second transform size are each selected from the group consisting of:

8192, 16384, and 32768.

33. The method of claim 28, wherein the first cyclic prefix size and the second cyclic prefix size are each selected from the group consisting of:

192, 384, 512, 768, 1024, 1536, 2048, 3072, and 4096 samples.

34. An apparatus, comprising:

a processor configured to generate a data frame; and

a transmitter configured to wirelessly broadcast the data frame,

wherein the data frame comprises a first set of orthogonal frequency domain multiplexing (OFDM) symbols and a second set of OFDM symbols, each OFDM symbol in the first set of OFDM symbols and the second set of OFDM symbols comprising a useful portion and a cyclic prefix,

wherein, to generate each OFDM symbol, the processor is further configured to;

convert a block of frequency domain data to time-domain samples using an inverse fast Fourier transform having a transform size to form the useful portion; and

form the cyclic prefix by prepending to said each OFDM symbol a plurality of time-domain samples from the end of the useful portion,

wherein the block of frequency domain data corresponding to the first set of OFDM symbols comprises a parameter indicating a sampling rate corresponding to the second set of OFDM symbols.

35. The apparatus of claim 34, wherein the sampling rate corresponding to the second set of OFDM symbols is different than a sampling rate corresponding to the first set of OFDM symbols.