Increased capacity communications systems, methods and/or devices

• US 8,462,860 B2
• Filed: 06/09/2009
• Issued: 06/11/2013
• Est. Priority Date: 07/07/2008
• Status: Active Grant

• Current Assignee: Odyssey Wireless, Inc.
• Original Assignee: Odyssey Wireless, Inc.
• Inventors: Karabinis, Peter D.
• Primary Examiner(s): FILE, ERIN M
• Application Number:
  US12/481,084
• Publication Number:
  US 20100002789A1
• Time in Patent Office: 1,463 Days
• Field of Search: 375/260
• US Class Current: 375/260
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

Communications architectures, systems, devices and/or methods are disclosed that can increase capacity of conventional OFDM/OFDMA systems, devices, methods and/or protocols by as much as 100%. Conventional OFDM/OFDMA transmitter/receiver architectures, methods, systems and/or devices are improved upon via additional signal processing to provide the increased capacity and reduce non-linear distortion effects on higher-order modulation alphabets such as, for example, 256-QAM.

Claims

1. A method comprising:

receiving by a receiver a signal comprising N first sub-carriers and M second sub-carriers;

wherein N≧

2, M≧

1, the N first sub-carriers are received over a set of frequencies and over a T seconds time interval, the M second sub-carriers are received over at least some of the set of frequencies and, at least partially, over the T seconds time interval, the N first sub-carriers are orthogonal therebetween, the M second sub-carriers are orthogonal therebetween when M>

1 and wherein at least one of the M second sub-carriers is not orthogonal to at least one of the N first sub-carriers;

processing the N first sub-carriers and the M second sub-carriers jointly at the receiver to reduce interference from the N first sub-carriers into the M second subcarriers and/or from the M second sub-carriers into the N first sub-carriers; and

deriving data responsive to said jointly processing,

wherein a spacing between two adjacent sub-carriers of the N first sub-carriers is 1/T Hz, a spacing between two adjacent sub-carriers of the M second sub-carriers is 1/T Hz and a spacing between a first sub-carrier of the N first sub-carriers and a sub-carrier of the M second sub-carriers that is adjacent to the first sub-carrier of the N first sub-carriers is less than 1/T Hz.

2. The method according to claim 1, wherein said jointly processing comprises:

generating at the receiver at least 2N samples of the signal;

performing a first transformation on a first sub-set of the at least 2N samples;

performing a second transformation on a second sub-set of the at least 2N samples; and

combining an output of the first transformation with an output of the second transformation.

3. The method according to claim 1, wherein a spacing between two adjacent sub-carriers of the N first sub-carriers is 1/T Hz, a spacing between two adjacent sub-carriers of the M second sub-carriers is 1/T Hz and a spacing between a first sub-carrier of the N first sub-carriers and a sub-carrier of the M second sub-carriers that is adjacent to the first sub-carrier of the N first sub-carriers is ½

T Hz.

4. The method according to claim 2, wherein the first sub-set of the at least 2N samples comprises at least N samples and the second sub-set of the at least 2N samples comprises at least N samples.

5. The method according to claim 4, wherein a spacing in time between two adjacent samples of the first sub-set is T/N seconds, a spacing in time between two adjacent samples of the second sub-set is T/N seconds and a spacing in time between a first sample of the first sub-set and a sample of the second sub-set that is adjacent in time to the first sample of the first sub-set is T/2N seconds.

6. The method according to claim 2, wherein the first transformation and the second transformation each comprises a time-domain to frequency-domain transformation.

7. The method according to claim 6, wherein the time-domain is a discrete time-domain, the frequency-domain is a discrete frequency-domain and wherein the time-domain to frequency-domain transformation comprises a Discrete Fourier Transform and/or a Fast Fourier Transform.

8. The method according to claim 2, further comprising modifying the output of the first transformation and/or modifying the output of the second transformation prior to the combining.

9. The method according to claim 8, wherein combining comprises:

forming γ

^Tb+δ

^Tr;

wherein b comprises the output of the first transformation, r comprises the output of the second transformation, γ

^Tb comprises modifying the output of the first transformation, δ

^Tr comprises modifying the output of the second transformation and wherein the superscript T denotes transpose and/or conjugate transpose.

10. The method according to claim 9, further comprising:

calculating γ and

δ

such that the statistical expectation E[|γ

^Tb+δ

^Tr−

B_k|²] is minimized;

wherein E[•

] denotes statistical expectation, |•

| denotes magnitude and B_k denotes a data element that is associated with a k^th sub-carrier;

k=1, 2, . . . , N.

11. The method according to claim 10, wherein calculating comprises calculating for at least one value of k;

k=1, 2, . . . , N.

12. The method according to claim 11, further comprising:

using γ

^Tb+δ

^Tr to determine an estimate of B_k for at least one value of k.

13. The method according to claim 1, further comprising:

transmitting by a transmitter the N first sub-carriers, N≧

2, over the set of frequencies such that the N first sub-carriers span a time duration of T seconds and are orthogonal therebetween; and

transmitting by the transmitter the M second sub-carriers, M≧

1, at least partially concurrently with said transmitting by the transmitter the N first sub-carriers, using at least some of the set of frequencies, such that the M second sub-carriers are orthogonal therebetween, when M>

1;

wherein at least one of the M second sub-carriers is not orthogonal to at least one of the N first sub-carriers.

14. The method according to claim 13, further comprising:

transmitting the N first sub-carriers using a first antenna element/pattern of the transmitter; and

transmitting the M second sub-carriers using a second antenna element/pattern of the transmitter.

15. The method according to claim 14, wherein transmitting the N first sub-carriers using a first antenna element/pattern of the transmitter comprises transmitting the N first sub-carriers to a first device and wherein transmitting the M second sub-carriers using a second antenna element/pattern of the transmitter comprises transmitting the M second sub-carriers to a second device that is at a distance from the first device.

16. The method according to claim 1, wherein said receiving by a receiver a signal comprising N first sub-carriers and M second sub-carriers comprises:

receiving by the receiver the N first sub-carriers from a first device; and

receiving by the receiver the M second sub-carriers from a second device that is at a distance from the first device.

17. The method according to claim 16, wherein receiving by the receiver the N first sub-carriers from a first device comprises using a first antenna element/pattern of the receiver and wherein receiving by the receiver the M second sub-carriers from a second device comprises using a second antenna element/pattern of the receiver.

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

segregating by a transmitter a plurality of sub-carriers into first and second subsets of sub-carriers;

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

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

transmitting by the transmitter the amplified first subset of sub-carriers and the amplified second subset of sub-carriers.

19. The method according to claim 18, further comprising:

prior to said transmitting, combining the amplified first subset of sub-carriers with the amplified second subset of sub-carriers; and

exciting a transmission medium with the amplified first subset of sub-carriers and the amplified second subset of sub-carriers that have been combined.

20. The method according to claim 19, wherein said exciting a transmission medium comprises:

providing the amplified first subset of sub-carriers and the amplified second subset of sub-carriers that have been combined to an antenna; and

radiating from the antenna the amplified first subset of sub-carriers and the amplified second subset of sub-carriers that have been combined.

21. The method according to claim 18, further comprising:

prior to said transmitting, maintaining the amplified first subset of sub-carriers segregated from the amplified second subset of sub-carriers; and

exciting a transmission medium with the amplified first subset of sub-carriers and the amplified second subset of sub-carriers that have been maintained segregated therebetween.

22. The method according to claim 21, wherein said exciting a transmission medium comprises:

providing the amplified first subset of sub-carriers and the amplified second subset of sub-carriers to respective first and second antennas; and

radiating from the first and second antennas, respectively, the amplified first subset of sub-carriers and the amplified second subset of sub-carriers.

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

transmitting by a transmitter the signal comprising the N first sub-carriers and the M second sub-carriers;

wherein N≧

2, M≧

1;

wherein the N first sub-carriers are transmitted by the transmitter over the set of frequencies and over the T seconds time interval;

wherein the M second sub-carriers are transmitted by the transmitter over at least some of the set of frequencies and, at least partially, over the T seconds time interval;

wherein the N first sub-carriers are transmitted by the transmitter such that they are orthogonal therebetween;

wherein the M second sub-carriers are transmitted by the transmitter such that they are orthogonal therebetween when M>

1; and

wherein the N first sub-carriers and the M second sub-carriers are transmitted by the transmitter such that at least one of the M second sub-carriers is not orthogonal to at least one of the N first sub-carriers.

24. The method according to claim 23, wherein said transmitting by a transmitter the signal comprising the N first sub-carriers and the M second sub-carriers comprises:

transmitting by the transmitter the N first sub-carriers using a first component of the transmitter; and

transmitting by the transmitter the M second sub-carriers using a second component of the transmitter that is physically separate and at a distance from the first component of the transmitter.

25. The method according to claim 23, further comprising:

amplifying the N first sub-carriers and the M second sub-carriers using respective first and second different amplifiers by the transmitter.

26. The method according to claim 23, further comprising:

transmitting the N first sub-carriers and the M second sub-carriers using respective first and second different antennas by the transmitter.

27. The method according to claim 1, wherein said receiving by a receiver a signal comprising N first sub-carriers and M second sub-carriers further comprises:

receiving by the receiver the N first sub-carriers using a first antenna of the receiver; and

receiving by the receiver the M second sub-carriers using a second antenna of the receiver that is different from the first antenna of the receiver.

28. A communications system comprising a receiver that is configured to:

receive a signal comprising N first sub-carriers and M second sub-carriers;

wherein N≧

2, M≧

1, the N first sub-carriers are received by the receiver over a set of frequencies and over a T seconds time interval, the M second sub-carriers are received by the receiver over at least some of the set of frequencies and, at least partially, over the T seconds time interval, the N first sub-carriers are orthogonal therebetween, the M second sub-carriers are orthogonal therebetween when M>

1 and wherein at least one of the M second sub-carriers is not orthogonal to at least one of the N first sub-carriers;

process the N first sub-carriers and the M second sub-carriers jointly to reduce interference from the N first sub-carriers into the M second subcarriers and/or from the M second sub-carriers into the N first sub-carriers; and

derive data responsive to having processed jointly the N first sub-carriers and the M second sub-carriers,

wherein a spacing between two adjacent sub-carriers of the N first sub-carriers is 1/T Hz, a spacing between two adjacent sub-carriers of the M second sub-carriers is 1/T Hz and a spacing between a first sub-carrier of the N first sub-carriers and a sub-carrier of the M second sub-carriers that is adjacent to the first sub-carrier of the N first sub-carriers is less than 1/T Hz.

29. The communications system according to claim 28, wherein the receiver is further configured to:

generate at least 2N samples of the signal;

perform a first transformation on a first sub-set of the at least 2N samples;

perform a second transformation on a second sub-set of the at least 2N samples; and

combine an output of the first transformation with an output of the second transformation.

30. The communications system according to claim 28, wherein a spacing between two adjacent sub-carriers of the N first sub-carriers is 1/T Hz, a spacing between two adjacent sub-carriers of the M second sub-carriers is 1/T Hz and a spacing between a first sub-carrier of the N first sub-carriers and a sub-carrier of the M second sub-carriers that is adjacent to the first sub-carrier of the N first sub-carriers is ½

T Hz.

31. The communications system according to claim 29, wherein the first sub-set of the at least 2N samples comprises at least N samples and the second sub-set of the at least 2N samples comprises at least N samples.

32. The communications system according to claim 31, wherein a spacing in time between two adjacent samples of the first sub-set is T/N seconds, a spacing in time between two adjacent samples of the second sub-set is T/N seconds and a spacing in time between a first sample of the first sub-set and a sample of the second sub-set that is adjacent in time to the first sample of the first sub-set is T/2N seconds.

33. The communications system according to claim 29, wherein the first transformation and the second transformation each comprises a time-domain to frequency-domain transformation.

34. The communications system according to claim 33, wherein the time-domain is a discrete time-domain, the frequency-domain is a discrete frequency-domain and wherein the time-domain to frequency-domain transformation comprises a Discrete Fourier Transform and/or a Fast Fourier Transform.

35. The communications system according to claim 29, wherein the receiver is further configured to modify the output of the first transformation and/or to modify the output of the second transformation before the receiver combines the output of the first transformation with the output of the second transformation.

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

^Tb+δ

^Tr;

wherein b comprises the output of the first transformation, r comprises the output of the second transformation, γ

^Tb comprises the modified output of the first transformation, δ

^Tr comprises the modified output of the second transformation and wherein the superscript T denotes transpose and/or conjugate transpose.

37. The communications system according to claim 36, wherein the receiver is further configured to calculate the vectors γ

and δ

such that the statistical expectation E[|γ

^Tb+δ

^Tr−

B_k|²] is minimized;

wherein E[•

] denotes statistical expectation, |•

| denotes magnitude and B_k denotes a data element that is associated with a k^th sub-carrier;

k=1, 2, . . . , N.

38. The communications system according to claim 37, wherein the receiver is configured to calculate the vectors γ

and δ

for at least one value of k;

k=1, 2, . . . , N.

39. The communications system according to claim 38, wherein the receiver is further configured to use γ

^Tb+δ

^Tr to determine an estimate of B_k for at least one value of k.

40. The communications system according to claim 28, further comprising a transmitter that is configured to:

transmit the N first sub-carriers, N≧

2, over the set of frequencies such that the N first sub-carriers span a time duration of T seconds and are orthogonal therebetween; and

transmit the M second sub-carriers, M≧

1, at least partially concurrently with the N first sub-carriers, using at least some of the set of frequencies, such that the M second sub-carriers are orthogonal therebetween, when M>

1;

wherein at least one of the M second sub-carriers is not orthogonal to at least one of the N first sub-carriers.

41. The communications system according to claim 40, wherein the transmitter is further configured to:

transmit the N first sub-carriers using a first antenna element/pattern of the transmitter; and

transmit the M second sub-carriers using a second antenna element/pattern of the transmitter.

42. The communications system according to claim 41, wherein the transmitter transmits the N first sub-carriers to a first device using the first antenna element/pattern of the transmitter and transmits the M second sub-carriers to a second device, that is at a distance from the first device, using the second antenna element/pattern of the transmitter.

43. The communications system according to claim 28, wherein the N first sub-carriers are received at the receiver from a first device and the M second sub-carriers are received at the receiver from a second device that is at a distance from the first device.

44. The communications system according to claim 43, wherein a first antenna element/pattern is used by the receiver to receive the N first sub-carriers from the first device and a second antenna element/pattern is used by the receiver to receive the M second sub-carriers from the second device.

45. The communications system according to claim 28, further comprising a transmitter that is configured to:

segregate a plurality of sub-carriers into first and second subsets of sub-carriers;

use a first amplifier to amplify the first subset of sub-carriers;

use a second amplifier to amplify the second subset of sub-carriers; and

transmit the amplified first subset of sub-carriers and the amplified second subset of sub-carriers.

46. The communications system according to claim 45, wherein the transmitter is further configured to:

combine the amplified first subset of sub-carriers with the amplified second subset of sub-carriers prior to transmission thereof; and

excite a transmission medium with the amplified first subset of sub-carriers and the amplified second subset of sub-carriers that have been combined.

47. The communications system according to claim 46, wherein the transmitter is configured to excite the transmission medium by providing the amplified first subset of sub-carriers and the amplified second subset of sub-carriers that have been combined to an antenna and to radiate from the antenna the amplified first subset of sub-carriers and the amplified second subset of sub-carriers that have been combined.

48. The communications system according to claim 45, wherein the transmitter is further configured to:

maintain the amplified first subset of sub-carriers segregated from the amplified second subset of sub-carriers; and

excite a transmission medium with the amplified first subset of sub-carriers and the amplified second subset of sub-carriers that are maintained segregated therebetween by the transmitter.

49. The communications system according to claim 48, wherein the transmitter is configured to excite the transmission medium by providing the amplified first subset of sub-carriers and the amplified second subset of sub-carriers that are maintained segregated therebetween to respective first and second antennas and to radiate from the first and second antennas, respectively, the amplified first subset of sub-carriers and the amplified second subset of sub-carriers.

50. The communications system according to claim 28, further comprising:

a transmitter that is configured to transmit the signal comprising the N first sub-carriers and the M second sub-carriers;

wherein N≧

2, M≧

1;

wherein the N first sub-carriers are transmitted by the transmitter over the set of frequencies and over the T seconds time interval;

wherein the M second sub-carriers are transmitted by the transmitter over at least some of the set of frequencies and, at least partially, over the T seconds time interval;

wherein the N first sub-carriers are transmitted by the transmitter such that they are orthogonal therebetween;

wherein the M second sub-carriers are transmitted by the transmitter such that they are orthogonal therebetween when M>

1; and

wherein the N first sub-carriers and the M second sub-carriers are transmitted by the transmitter such that at least one of the M second sub-carriers is not orthogonal to at least one of the N first sub-carriers.

51. The communications system according to claim 50, wherein the transmitter is configured to transmit the N first sub-carriers using a first component of the transmitter;

and to transmit the M second sub-carriers using a second component of the transmitter that is physically separate and at a distance from the first component of the transmitter.

52. The communications system according to claim 50, wherein the transmitter is configured to amplify the N first sub-carriers and the M second sub-carriers using respective first and second different amplifiers of the transmitter.

53. The communications system according to claim 50, wherein the transmitter is configured to transmit the N first sub-carriers and the M second sub-carriers using respective first and second different antennas of the transmitter.

54. The communications system according to claim 28, wherein the receiver is configured to receive the N first sub-carriers using a first antenna of the receiver;

and is further configured to receive the M second sub-carriers using a second antenna of the receiver that is different from the first antenna of the receiver.