Increased capacity communications for OFDM-based wireless communications systems/methods/devices

• US 8,233,554 B2
• Filed: 03/29/2010
• Issued: 07/31/2012
• Est. Priority Date: 03/29/2010
• Status: Active Grant

• Current Assignee: Odyssey Wireless, Inc.
• Original Assignee: Odyssey Wireless, Inc.
• Inventors: Karabinis, Peter D.
• Primary Examiner(s): Wang, Ted
• Application Number:
  US12/748,931
• Publication Number:
  US 20110235728A1
• Time in Patent Office: 855 Days
• Field of Search: 375/260, 375/267, 375/295, 375/299
• US Class Current: 375/260
• CPC Class Codes: H03F 3/24 of transmitter output stages
• CPC Class Codes: H04B 1/04 Circuits
• CPC Class Codes: H04B 2001/0408 with power amplifiers
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04B 7/068 using space frequency diversity space-frequency coding H04L1/0606
• CPC Class Codes: H04B 7/0842 Weighted combining
• CPC Class Codes: H04B 7/0885 with combination
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04B 7/26 at least one of which is mobile
• CPC Class Codes: H04J 11/0036 at the receiver
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/0224 using sounding signals
• CPC Class Codes: H04L 25/03006 Arrangements for removing intersymbol interference
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 27/2627 Modulators
• CPC Class Codes: H04L 27/2633 using partial FFTs
• 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 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/26522 using partial FFTs
• 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 5/0007 : the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04W 72/046 : the resource being in the space domain, e.g. beams

Abstract

Numerous embodiments are provided that may be used to provide enhanced capacity and/or Quality-of-Service for OFDM-based systems such as LTE and/or WiMAX. Various service/device modes and/or applications are also provided. According to embodiments of the invention, a transformation may be performed on a data vector by a transmitter, prior to the transmitter transmitting the data vector, to distribute elements of the data vector over an available frequency space, thus providing robustness to channel anomalies such as fading and/or interference. The transformation may be based upon a Fourier transform or a truncated Butler matrix. At a receiver, an inverse of the transformation may be applied to recover data. The receiver and/or transmitter may be configured with an antenna array that may comprise a two-dimensional lattice of antenna elements, and may further be configured to estimate a number of resolvable signal paths and to form a spatial filter/rake that is matched to the number of resolvable signal paths. Embodiments relating to architectures, systems, methods, devices, software, firmware and/or computer program products are provided.

Claims

1. A communications method comprising:

forming a data vector comprising N data elements;

N≧

2;

subjecting the data vector to a transformation and forming a transformed vector responsive to said subjecting;

inserting at least one pilot symbol into the transformed vector and forming an augmented vector responsive to said inserting; and

transmitting by a transmitter the augmented vector;

wherein subjecting the data vector to a transformation occurs prior to said inserting at least one pilot symbol into the transformed vector and forming an augmented vector and wherein transmitting by a transmitter the augmented vector comprises transmitting by the transmitter simultaneously in time a plurality of sub-carriers;

wherein the transformation distributes an element/component/dimension of the data vector over a plurality of elements/components/dimensions of the transformed vector; and

wherein an element/component/dimension of the transformed vector comprises a superposition of values of a plurality of elements/components/dimensions of the data vector.

2. The communications method according to claim 1, further comprising:

prior to said transmitting by a transmitter, subjecting the augmented vector to a further transformation that depends upon a characteristic of a channel that exists between the transmitter and a receiver.

3. The communications method according to claim 1, wherein the transformation is based upon a Discrete Fourier Transform (DFT) and/or a Fast Fourier Transform (FFT).

4. The communications method according to claim 1, wherein the transformation is based upon a Butler matrix that is a truncated Butler matrix.

5. The communications method according to claim 1, further comprising:

receiving at a receiver the augmented vector responsive to said transmitting by a transmitter the augmented vector;

forming an estimate of the transformed vector at the receiver responsive to processing of the augmented vector that is received at the receiver;

subjecting the estimate of the transformed vector to an inverse of the transformation that the data vector has been subjected to at the transmitter; and

forming an estimate of the data vector responsive to said subjecting the estimate of the transformed vector to an inverse of the transformation.

6. The communications method according to claim 5, further comprising:

estimating at the receiver, responsive to a processing of the at least one pilot symbol by the receiver, a state of a communications channel through which said receiving occurs; and

providing data to the transmitter responsive to said estimating at the receiver.

7. The communications method according to claim 1, further comprising:

receiving at a receiver using a spatial matched filter and/or a spatial rake.

8. The communications method according to claim 7, wherein receiving at the receiver using a matched filter and/or a spatial rake comprises:

determining at the receiver a number of signal paths arriving at the receiver; and

forming at the receiver a respective number of antenna lobes and/or spatial fingers responsive to said determining at the receiver.

9. The communications method according to claim 8, wherein said determining at the receiver a number of signal paths arriving at the receiver comprises:

forming at the receiver an initial number of antenna lobes and/or spatial fingers; and

processing at the receiver a respective initial number of signals that is provided by the initial number of antenna lobes and/or spatial fingers that is formed;

wherein the initial number of lobes and/or spatial fingers that is formed at the receiver is greater than the determined number of signal paths arriving at the receiver.

10. The communications method according to claim 8, further comprising:

combining at the receiver a respective number of signals that is provided by the respective number of antenna lobes and/or spatial fingers that is formed.

11. The communications method according to claim 9, wherein the initial number of lobes and/or spatial fingers that is formed at the receiver spans a grid of two-dimensional space.

12. The communications method according to claim 7, wherein said receiving at a receiver further comprises:

receiving at an antenna of the receiver that is situated at a distance from a processor of the receiver;

amplifying following said receiving at an antenna of the receiver;

wirelessly transmitting over a short-range link following said amplifying; and

receiving at the processor of the receiver responsive to said wirelessly transmitting.

13. The communications method according to claim 12, wherein the antenna of the receiver comprises a two-dimensional lattice of antenna elements.

14. The communications method according to claim 1, further comprising:

forming a plurality of data vectors comprising data to be transmitted to a respective plurality of receivers;

subjecting each one of the plurality of data vectors to the transformation and forming a respective plurality of transformed vectors responsive to said subjecting each one of the plurality of data vectors to the transformation;

inserting at least one pilot symbol into each one of the respective plurality of transformed vectors and forming a respective plurality of augmented vectors; and

sequentially transmitting by the transmitter the respective plurality of augmented vectors to the respective plurality of receivers;

wherein sequentially transmitting comprises sequentially transmitting and avoiding overlapping in time between any two of the respective plurality of augmented vectors that are sequentially transmitted by the transmitter.

15. The communications method according to claim 1, wherein transmitting by a transmitter the augmented vector further comprises:

generating a plurality of replicas of the augmented vector; and

transmitting by the transmitter the plurality of replicas of the augmented vector using a respective plurality of antenna elements.

16. The communications method according to claim 1, wherein an element of the transformed vector comprises a value that is a linear superposition of a plurality of values of a respective plurality of elements of the data vector.

17. The communications method according to claim 1, wherein each element of the transformed vector comprises a value that is a linear superposition of a plurality of values of a respective plurality of elements of the data vector.

18. The communications method according to claim 1, further comprising:

transmitting by the transmitter the augmented vector over a plurality of frequency intervals that are non-contiguous therebetween; and

/or

transmitting by the transmitter the augmented vector over a plurality of time intervals that are non-contiguous therebetween.

19. The communications method according to claim 1, further comprising:

subjecting the augmented vector to a further transformation comprising at least one element that is generated pseudo-randomly to thereby provide increased communications security, covertness and/or privacy.

20. The communications method according to claim 1, further comprising:

amplifying by the transmitter a first subset of the plurality of sub-carriers using a first amplifier; and

amplifying by the transmitter a second subset of the plurality of sub-carriers using a second amplifier;

wherein each one of the first and second subsets of the plurality of sub-carriers comprises at least one sub-carrier of the plurality of sub-carriers.

21. The communications method according to claim 1, further comprising:

using by the transmitter a plurality of amplifiers that are configured in accordance with a Butler matrix architecture to amplify the augmented vector prior to said transmitting.

22. The communications method according to claim 1, further comprising:

using by the transmitter a plurality of antennas that are configured to transmit a respective plurality of augmented vectors so as to increase a signal-to-noise/interference ratio at a receiver by providing the respective plurality of augmented vectors at an antenna of the receiver substantially coherently therebetween;

wherein each antenna of the plurality of antennas is configured to transmit a replica of the augmented vector.

23. The communications method according to claim 1, further comprising:

transmitting by the transmitter information to a first and to a second device sequentially in time, over respective non-overlapping first and second time intervals; and

refraining by the transmitter from transmitting information to the first and to the second device simultaneously in time.

24. The communications method according to claim 1, wherein an element of the transformed vector comprises a value that is a non-linear combination of a plurality of values of a respective plurality of elements of the data vector.

25. A communications system comprising a transmitter that is configured:

to form a data vector comprising N data elements;

N≧

2;

to subject the data vector to a transformation and to form a transformed vector responsive to having subjected the data vector to the transformation;

to insert at least one pilot symbol into the transformed vector and to form an augmented vector responsive to having inserted the at least one pilot symbol into the transformed vector; and

to transmit the augmented vector;

wherein the transmitter is configured to subject the data vector to the transformation prior to inserting the at least one pilot symbol into the transformed vector and prior to forming the augmented vector and wherein the transmitter is configured to transmit the augmented vector by transmitting simultaneously in time a plurality of sub-carriers;

wherein the transformation distributes an element/component/dimension of the data vector over a plurality of elements/components/dimensions of the transformed vector; and

wherein an element/component/dimension of the transformed vector comprises a superposition of values of a plurality of elements/components/dimensions of the data vector.

26. The communications system according to claim 25, wherein the transmitter, prior to transmitting the augmented vector, is configured to subject the augmented vector to a further transformation that depends upon a characteristic of a channel that exists between the transmitter and a receiver.

27. The communications system according to claim 25, wherein the transformation is based upon a Discrete Fourier Transform (DFT) and/or a Fast Fourier Transform (FFT).

28. The communications system according to claim 25, wherein the transformation is based upon a Butler matrix that is a truncated Butler matrix.

29. The communications system according to claim 25, further comprising a receiver that is configured:

to receive the augmented vector responsive to the transmitter having transmitted the augmented vector;

to form an estimate of the transformed vector by processing the augmented vector that is received;

to subject the estimate of the transformed vector to an inverse of the transformation that the data vector has been subjected to by the transmitter; and

to form an estimate of the data vector responsive to having subjected the estimate of the transformed vector to the inverse of the transformation.

30. The communications system according to claim 29, wherein the receiver is further configured to estimate a state of a communications channel through which the transmitter is transmitting and the receiver is receiving, responsive to a processing of the at least one pilot symbol by the receiver, and to provide data to the transmitter responsive to the processing of the at least one pilot symbol.

31. The communications system according to claim 25, wherein the transmitter is further configured:

to form a plurality of data vectors comprising data to be transmitted by the transmitter to a respective plurality of receivers;

to subject each one of the plurality of data vectors to the transformation and to form a respective plurality of transformed vectors responsive to having subjected each one of the plurality of data vectors to the transformation;

to insert at least one pilot symbol into each one of the respective plurality of transformed vectors thus forming a respective plurality of augmented vectors; and

to sequentially transmit the respective plurality of augmented vectors to the respective plurality of receivers;

wherein the transmitter is configured to sequentially transmit the respective plurality of augmented vectors to the respective plurality of receivers while avoiding any time overlap between any two of the respective plurality of augmented vectors that are sequentially transmitted by the transmitter.

32. The communications system according to claim 25, wherein the transmitter is further configured:

to generate a plurality of replicas of the augmented vector; and

to transmit the plurality of replicas of the augmented vector using a respective plurality of antenna elements.

33. The communications system according to claim 32, wherein all replicas that are included in the plurality of replicas of the augmented vector are transmitted by the respective plurality of antenna elements substantially concurrently/simultaneously in time.

34. The communications system according to claim 25, further comprising a receiver that is configured to use a spatial matched filter and/or a spatial rake.

35. The communications system according to claim 34, wherein the receiver that is further configured to use a matched filter and/or a spatial rake is further configured:

to determine a number of signal paths arriving at the receiver; and

to form a respective number of antenna lobes and/or spatial fingers responsive to having determined the number of signal paths arriving at the receiver.

36. The communications system according to claim 35, wherein the receiver is further configured:

to form an initial number of antenna lobes and/or spatial fingers; and

to process a respective initial number of signals that is provided by the initial number of antenna lobes and/or spatial fingers that is formed;

wherein the initial number of lobes and/or spatial fingers that is formed at the receiver is greater than the determined number of signal paths arriving at the receiver.

37. The communications system according to claim 35, wherein the receiver is further configured to combine a respective number of signals that is provided by the respective number of antenna lobes and/or spatial fingers that is formed.

38. The communications system according to claim 36, wherein the initial number of lobes and/or spatial fingers that is formed by the receiver spans a grid of two-dimensional space.

39. The communications system according to claim 34, wherein the receiver is further configured:

to receive a signal at an antenna of the receiver that is situated at a distance from a processor of the receiver;

to amplify the signal that is received at the antenna;

to wirelessly transmit the amplified signal over a short-range link; and

to receive at the processor the signal that has been wirelessly transmitted over the short-range link.

40. The communications system according to claim 39, wherein the antenna of the receiver comprises a two-dimensional lattice of antenna elements.

41. The communications system according to claim 25, wherein an element of the transformed vector comprises a value that is a linear superposition of a plurality of values of a respective plurality of elements of the data vector.

42. The communications system according to claim 25, wherein each element of the transformed vector comprises a value that is a linear superposition of a plurality of values of a respective plurality of elements of the data vector.

43. The communications system according to claim 25, wherein the transmitter is further configured to transmit the augmented vector over a plurality of frequency intervals that are non-contiguous therebetween and/or over a plurality of time intervals that are non-contiguous therebetween.

44. The communications system according to claim 25, wherein the transmitter, prior to transmitting the augmented vector, is further configured to subject the augmented vector to a further transformation comprising at least one element that is generated pseudo-randomly to thereby provide increased communications security, covertness and/or privacy.

45. The communications system according to claim 25, wherein the transmitter that is configured to transmit the augmented vector by transmitting simultaneously in time a plurality of sub-carriers is further configured:

to amplify a first subset of the plurality of sub-carriers using a first amplifier; and

to amplify a second subset of the plurality of sub-carriers using a second amplifier;

wherein each one of the first and second subsets of the plurality of sub-carriers comprises at least one sub-carrier of the plurality of sub-carriers.

46. The communications system according to claim 25, wherein the transmitter that is configured to transmit the augmented vector by transmitting simultaneously in time a plurality of sub-carriers comprises a plurality of amplifiers that are configured in accordance with a Butler matrix architecture and wherein the transmitter is configured to use the plurality of amplifiers that are configured in accordance with the Butler matrix architecture to amplify the augmented vector.

47. The communications system according to claim 25, wherein the transmitter that is configured to transmit the augmented vector by transmitting simultaneously in time a plurality of sub-carriers comprises a plurality of antennas that are configured to transmit a respective plurality of augmented vectors so as to increase a signal-to-noise/interference ratio at a receiver by providing the respective plurality of augmented vectors at an antenna of the receiver substantially coherently therebetween;

wherein each antenna of the plurality of antennas is configured to transmit a replica of the augmented vector.

48. The communications system according to claim 25, wherein the transmitter that is configured to transmit the augmented vector by transmitting simultaneously in time a plurality of sub-carriers is further configured to transmit information to a first and to a second device sequentially in time, over respective non-overlapping first and second time intervals, and is also configured to refrain from transmitting information to the first and to the second device simultaneously in time.