Time varying delay diversity of OFDM

• US 9,100,076 B2
• Filed: 07/16/2012
• Issued: 08/04/2015
• Est. Priority Date: 05/17/2004
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Naguib, Ayman Fawzy, Agrawal, Avneesh
• Primary Examiner(s): Fotakis, Aristocratis
• Application Number:
  US13/550,549
• Publication Number:
  US 20120328045A1
• Time in Patent Office: 1,114 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 7/0417 Feedback systems
• CPC Class Codes: H04B 7/0632 Channel quality parameters, e.g. channel quality indicator [CQI]
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0673 using feedback from receiving side
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0618 Space-time coding
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 27/2634 Inverse fast Fourier transform [IFFT] or inverse discrete Fourier transform [IDFT] modulators in combination with other circuits for modulation
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Methods and apparatuses that apply a time-varying delay to symbols to be transmitted from one or more antennas are provided. In a first embodiment, first and second transmission orders for samples in first and second data symbols, respectively, are determined. First and second cyclic prefixes are appended to the beginnings of the first and second transmission orders, respectively. The first and second data symbols are then provided to the same antenna for transmissions beginning at different time slots in accordance with a delay diversity scheme. In a second embodiment, either the first data symbol or the second data symbol can be provided to different antennas for transmissions beginning at different time slots in accordance with a delay diversity scheme.

Claims

1. A method of wireless transmission, comprising:

determining a first transmission order for a first plurality of samples of a first data symbol;

determining a second transmission order for a second plurality of samples of a second data symbol;

determining a first cyclic prefix for the first data symbol that is based on a first subset of the first plurality of samples;

determining a second cyclic prefix for the second data symbol that is based on a second subset of the second plurality of samples;

appending the first cyclic prefix to a beginning of the first transmission order;

appending the second cyclic prefix to a beginning of the second transmission order;

providing the first data symbol to a given single antenna for transmission based on the appended first transmission order starting at a first sample period position of a first time slot; and

providing the second data symbol to the given single antenna for transmission based on the appended second transmission order starting at a second sample period position of a second time slot, wherein a delay between a starting point of the second time slot and a starting point of the second sample period position of the second time slot is changed from a delay between a starting point of the first time slot and a starting point of the first sample period position of the first time slot in accordance with a time varying delay scheme;

wherein the first and second data symbols are consecutive data symbols in a symbol stream that are to be consecutively transmitted by the given single antenna.

2. The method of claim 1, wherein the delay change is a single sample period.

3. The method of claim 1, wherein the first and second subsets correspond to the last N samples within the first and second transmission orders, respectively, wherein N is an integer.

4. The method of claim 1, further comprising:

determining N transmission orders for a plurality of additional samples of N additional data symbols;

determining N cyclic prefixes for the N data symbols based on N respective subsets of the plurality of additional samples;

appending the N cyclic prefixes to beginnings of the N transmission orders, respectively; and

providing the N data symbols to the given single antenna for transmission based on the appended N transmission orders starting at respective sample period positions that are each delayed from N respective starting points of N additional time slots by a different number of sample periods,

wherein N is an integer.

5. The method of claim 1, wherein the second data symbol corresponds to a next transmitted symbol by the given single antenna following the transmission of the first data symbol.

6. The method of claim 1, wherein the delay change is a fixed slot delay that is maintained between transmissions of successive data symbol transmissions by the single given antenna.

7. The method of claim 6, further comprising:

providing a third data symbol to the given single antenna for transmission starting at a third sample period position of a third time slot,

wherein a delay between a starting point of the third time slot and a starting point of the third sample period position of the third time slot is changed from a delay between the starting point of the second time slot and the starting point of the first sample period position of the first time slot is based on the fixed slot delay.

8. The method of claim 1, wherein the delay change is a random slot delay that is determined based on a pseudo random sequence.

9. The method of claim 8, further comprising:

providing a third data symbol to the given single antenna for transmission starting at a third sample period position of a third time slot,

wherein a delay between a starting point of the third time slot and a starting point of the third sample period position of the third time slot is changed from a delay between the starting point of the second time slot and the starting point of the first sample period position of the first time slot is based on a different random slot delay.

10. The method of claim 1, wherein the delay change is dynamically calculated based on a mathematical function.

11. The method of claim 10, wherein the mathematical function corresponds to a time varying function.

12. The method of claim 11, wherein the time varying function includes a sine function and/or a cosine function.

13. The method of claim 1, wherein the delay change is (i) a multiple of a sample period, and/or (ii) a fraction of one or more sample periods.

14. The method of claim 1, wherein the delay change is based upon feedback information from a receiver in communication with the given single antenna.

15. The method of claim 14, wherein the feedback information corresponds to one or more channel quality indicators (CQIs) that describe a channel characteristic.

16. The method of claim 1, wherein no samples of the second data symbol are transmitted after the starting point of the second time slot and before the starting point of the second sample period position of the second time slot.

17. The method of claim 1, wherein the time varying delay scheme is a linear time-varying delay scheme.

18. A method of wireless transmission, comprising:

determining a transmission order for a plurality of samples of a data symbol;

determining a cyclic prefix for the data symbol that is based on a subset of the plurality of samples;

appending the cyclic prefix to a beginning of the transmission order;

providing the data symbol to a first antenna for transmission based on the appended transmission order starting at a first time slot; and

providing the data symbol to a second antenna for transmission based on the appended transmission order starting at a second time slot that is delayed from the first time slot in accordance with a delay diversity scheme,

wherein the delay from the first time slot to the second time slot corresponds to a random slot delay that is determined based on a pseudo random sequence.

19. The method of claim 18, wherein the second time slot is delayed from the first time slot by a single time slot.

20. The method of claim 18, wherein the subset corresponds to the last N samples within the transmission order, wherein N is an integer.

21. The method of claim 18, further comprising:

providing the data symbol to N antennas for transmission based on the appended transmission order starting at N time slots that are each delayed from the first time slot by a different number of slots,

wherein N is an integer.

22. The method of claim 18, further comprising:

providing the data symbol to a third antenna for transmission starting at a third time slot that is delayed from the second time slot based on a different random slot delay.

23. The method of claim 18, wherein the delay from the first time slot to the second time slot is dynamically calculated based on a mathematical function.

24. The method of claim 23, wherein the mathematical function corresponds to a time varying function.

25. The method of claim 24, wherein the time varying function includes a sine function and/or a cosine function.

26. The method of claim 18, wherein the delay between the first time slot and the second time slot corresponds to (i) a multiple of a sample period, and/or (ii) a fraction of one or more sample periods.

27. The method of claim 18, wherein the delay from the first time slot to the second time slot is based upon feedback information from a receiver in communication with the first and second antennas.

28. The method of claim 27, wherein the feedback information corresponds to one or more channel quality indicators (CQIs) that describe a channel characteristic.

29. The method of claim 18,

wherein the first and second time slots correspond to different sample period positions of a larger time slot.

30. A wireless transmission apparatus, comprising:

means for determining a first transmission order for a first plurality of samples of a first data symbol;

means for determining a second transmission order for a second plurality of samples of a second data symbol;

means for determining a first cyclic prefix for the first data symbol that is based on a first subset of the first plurality of samples;

means for determining a second cyclic prefix for the second data symbol that is based on a second subset of the second plurality of samples;

means for appending the first cyclic prefix to a beginning of the first transmission order;

means for appending the second cyclic prefix to a beginning of the second transmission order;

means for providing the first data symbol to a given single antenna for transmission based on the appended first transmission order starting at a first sample period position of a first time slot; and

means for providing the second data symbol to the given single antenna for transmission based on the appended second transmission order starting at a second sample period position of a second time slot, wherein a delay between a starting point of the second time slot and a starting point of the second sample period position of the second time slot is changed from a delay between a starting point of the first time slot and a starting point of the first sample period position of the first time slot in accordance with a time varying delay scheme;

wherein the first and second data symbols are consecutive data symbols in a symbol stream that are to be consecutively transmitted by the given single antenna.

31. A wireless transmission apparatus, comprising:

means for determining a transmission order for a plurality of samples of a data symbol;

means for determining a cyclic prefix for the data symbol that is based on a subset of the plurality of samples;

means for appending the cyclic prefix to a beginning of the transmission order;

means for providing the data symbol to a first antenna for transmission based on the appended transmission order starting at a first time slot; and

means for providing the data symbol to a second antenna for transmission based on the appended transmission order starting at a second time slot that is delayed from the first time slot in accordance with a delay diversity scheme,

wherein the delay from the first time slot to the second time slot corresponds to a random slot delay that is determined based on a pseudo random sequence.

32. A wireless transmission apparatus, comprising:

a transmitter; and

a processor coupled to the transmitter and configured to;

determine a first transmission order for a first plurality of samples of a first data symbol;

determine a second transmission order for a second plurality of samples of a second data symbol;

determine a first cyclic prefix for the first data symbol that is based on a first subset of the first plurality of samples;

determine a second cyclic prefix for the second data symbol that is based on a second subset of the second plurality of samples;

append the first cyclic prefix to a beginning of the first transmission order;

append the second cyclic prefix to a beginning of the second transmission order;

provide the first data symbol to a given single antenna for transmission based on the appended first transmission order starting at a first sample period position of a first time slot; and

provide the second data symbol to the given single antenna for transmission based on the appended second transmission order starting at a second sample period position of a second time slot, wherein a delay between a starting point of the second time slot and a starting point of the second sample period position of the second time slot is changed from a delay between a starting point of the first time slot and a starting point of the first sample period position of the first time slot in accordance with a time varying delay scheme;

wherein the first and second data symbols are consecutive data symbols in a symbol stream that are to be consecutively transmitted by the given single antenna.

33. A wireless transmission apparatus, comprising:

a transmitter; and

a processor coupled to the transmitter and configured to;

determine a transmission order for a plurality of samples of a data symbol;

determine a cyclic prefix for the data symbol that is based on a subset of the plurality of samples;

append the cyclic prefix to a beginning of the transmission order;

provide the data symbol to a first antenna for transmission based on the appended transmission order starting at a first time slot; and

provide the data symbol to a second antenna for transmission based on the appended transmission order starting at a second time slot that is delayed from the first time slot in accordance with a delay diversity scheme,

wherein the delay from the first time slot to the second time slot corresponds to a random slot delay that is determined based on a pseudo random sequence.

34. A non-transitory computer-readable medium containing instructions stored thereon, which, when executed by a wireless transmission apparatus, cause the wireless transmission apparatus to perform operations, the instructions comprising:

at least one instruction to cause the wireless transmission apparatus to determine a first transmission order for a first plurality of samples of a first data symbol;

at least one instruction to cause the wireless transmission apparatus to determine a second transmission order for a second plurality of samples of a second data symbol;

at least one instruction to cause the wireless transmission apparatus to determine a first cyclic prefix for the first data symbol that is based on a first subset of the first plurality of samples;

at least one instruction to cause the wireless transmission apparatus to determine a second cyclic prefix for the second data symbol that is based on a second subset of the second plurality of samples;

at least one instruction to cause the wireless transmission apparatus to append the first cyclic prefix to a beginning of the first transmission order;

at least one instruction to cause the wireless transmission apparatus to append the second cyclic prefix to a beginning of the second transmission order;

at least one instruction to cause the wireless transmission apparatus to provide the first data symbol to a given single antenna for transmission based on the appended first transmission order starting at a first sample period position of a first time slot; and

at least one instruction to cause the wireless transmission apparatus to provide the second data symbol to the given single antenna for transmission based on the appended second transmission order starting at a second sample period position of a second time slot, wherein a delay between a starting point of the second time slot and a starting point of the second sample period position of the second time slot is changed from a delay between a starting point of the first time slot and a starting point of the first sample period position of the first time slot in accordance with a time varying delay scheme;

wherein the first and second data symbols are consecutive data symbols in a symbol stream that are to be consecutively transmitted by the given single antenna.

35. A non-transitory computer-readable medium containing instructions stored thereon, which, when executed by a wireless transmission apparatus, cause the wireless transmission apparatus to perform operations, the instructions comprising:

determine a transmission order for a plurality of samples of a data symbol;

at least one instruction to cause the wireless transmission apparatus to determine a cyclic prefix for the data symbol that is based on a subset of the plurality of samples;

at least one instruction to cause the wireless transmission apparatus to append the cyclic prefix to a beginning of the transmission order;

at least one instruction to cause the wireless transmission apparatus to provide the data symbol to a first antenna for transmission based on the appended transmission order starting at a first time slot; and

at least one instruction to cause the wireless transmission apparatus to provide the data symbol to a second antenna for transmission based on the appended transmission order starting at a second time slot that is delayed from the first time slot in accordance with a delay diversity scheme,

wherein the delay from the first time slot to the second time slot corresponds to a random slot delay that is determined based on a pseudo random sequence.