Downlink broadcasting by sequential transmissions from a communication station having an antenna array

• US 7,299,071 B1
• Filed: 10/11/2000
• Issued: 11/20/2007
• Est. Priority Date: 12/10/1997
• Status: Expired due to Fees

• Current Assignee: Intel Corporation
• Original Assignee: ArrayComm LLC (Ygomi LLC)
• Inventors: Barratt, Craig H., Parish, David M., Uhlik, Christopher R., Boyd, Stephen, Yun, Louis C., Goldburg, Marc H.
• Primary Examiner(s): Gesesse, Tilahun
• Application Number:
  US09/689,228
• Time in Patent Office: 2,596 Days
• Field of Search: 455/562, 455/103, 455/105, 455/107, 455/129, 455/562.1, 455/524, 455/560, 455/561, 455/525, 455/277.1, 455/63.1, 370/334, 375/135, 375/145, 375/315, 375/296, 375/292, 375/146, 375/260, 375/269, 375/299
• US Class Current: 455/562.1
• CPC Class Codes: H01Q 1/246 specially adapted for base stations
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H04B 7/0697 using spatial multiplexing
• CPC Class Codes: H04W 16/28 using beam steering

Abstract

This invention relates to a method and apparatus for transmitting a downlink signal from a communication station to one or more subscriber units to achieve a desired radiation level over a desired sector (e.g., everywhere), the communication station including an array of antenna elements and one or more signal processors programmed (in the case of programmable signal processors) to weight the downlink signal according to one of a sequence of complex valued weight vectors. The method includes sequentially repeating transmitting the downlink signal, each repetition with a different weight vector from the sequence until all weight vectors in the sequence have been transmitted with. The sequence is designed for achieving the desired radiation level during at least one of the repetitions. In this way, every user in the desired region is transmitted to in the time period.

Claims

1. A method comprising:

developing a plurality of signal processing procedures by selecting a weight vector from a sequence of different weight vectors, wherein elements of the weight vectors selectively modify one or more characteristics of transmission of a signal from each antenna of an antenna array,

iteratively processing the signal through the plurality of signal processing procedures to generate a plurality of processed signals; and

sequentially transmitting the plurality of processed signals through a coupled antenna array, generating a desired radiation level at a number of locations within a desired sector.

2. A method according to claim 1, wherein the signal is transmitted using a CDMA protocol.

3. A method according to claim 1, wherein the desirable radiation level is a non-null level.

4. A method according to claim 1, wherein the desired sector is comprised of a range of azimuths up to a complete range of azimuths of the antenna array.

5. A method according to claim 1, wherein the transmission characteristics include one or more of signal amplitude and/or phase.

6. A method according to claim 5, wherein the sequence of weight vectors share an amplitude value and have random phase values.

7. A method according to claim 5, wherein the sequence of weight vectors is comprised of weight vectors that are orthogonal.

8. A method according to claim 7, wherein the orthogonal weight vectors have elements with the same magnitude.

9. A method according to claim 7, wherein the orthogonal weight vectors are developed from one or more of rows or columns of a complex valued Walsh-Hadamard matrix, rows or columns of a real valued Hadamard matrix, and/or a sequence whose elements are basis vectors of a Fourier transform.

10. A method according to claim 1, wherein the sequence of weight vectors is comprised of weight vectors designed to provide a desirable radiation pattern within at least a sub-sector of the desired sector.

11. A method according to claim 10, wherein the desirable radiation pattern is a near omni-directional radiation pattern.

12. A method according to claim 10, wherein the desired sector is the whole range in azimuth.

13. A method according to claim 1, wherein the sequence of weight vectors includes weight vectors that are representative of weight vectors designed for transmission to known communication unit(s).

14. A method according to claim 13, wherein the weight vectors designed for transmission to known communication unit(s) are determined from spatial signature(s) associated with each of the communication unit(s).

15. A method according to claim 13 wherein the communication unit(s) is at least one of a subscriber unit and a base station.

16. A method according to claim 1, wherein the weight vectors are determined from weight vectors designed for transmission to known subscriber unit(s) using a vector quantization clustering process.

17. A method according to claim 16, the vector quantization clustering process comprising:

assigning an initial set of weight vectors as a current set of representative weight vectors;

combining each designed for subscriber unit weight vector with its nearest representative weight vector in the current set, according to some association criterion;

determining an average measure of a distance between each representative weight vector in the current set and all weight vectors combined with that representative weight vector;

replacing each representative weight vector in the current set with a core weight vector for all the weight vectors that have been combined with that representative weight vector; and

iterative repeating the combining, determining and replacing steps until a magnitude of the difference between the average measure in a present iteration and the average distance in the previous iteration is less than a threshold.

18. A method according to claim 1, wherein the plurality of signal processing procedures is commensurate with the plurality of antennae within the antenna array used to sequentially transmit the plurality of processed signals.

19. A storage medium comprising content which, when executed by an accessing machine, implements a method according to claim 1.

20. A wireless communication system element comprising:

a storage medium including content; and

a processor element, coupled with the storage medium, to execute at least a subset of the content to implement a method according to claim 1.

21. A subscriber unit comprising:

two or more antennas configured as an antenna array; and

processing element(s), coupled with the antenna array, to select a weight vector from a sequence of different weight vectors to develop a plurality of signal processing procedures, wherein elements of the weight vectors selectively modify one or more characteristics of transmission of the signal from each antenna in the antenna array and to iteratively process a signal through the plurality of signal processing procedures to generate a plurality of processed signals which, when sequentially transmitted via the antenna array, generate a desired radiation level at a number of locations within a desired sector, wherein the desired sector is comprised of a range of azimuths up to a complete range of azimuths of the antenna array.

22. A subscriber unit according to claim 21, wherein the processing element(s) are comprised of one or more of an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable logic array (FPGA) and/or a microcontroller resident within the subscriber unit.

23. A subscriber unit according to claim 21, further comprising:

a transceiver, coupled with the antenna array and the processor element(s), to sequentially transmit each of the generated plurality of processed signals to achieve the desired radiation level at a number of locations in the desired sector during at least one of said sequential transmissions, wherein sequential transmission of the generated plurality of processed signals comprises a broadcast transmission.

24. A subscriber unit according to claim 23, wherein the processor element(s) are integrated within the transceiver.

25. A subscriber unit according to claim 24, wherein the transceiver comprises at least one processor element for each antenna within the antenna array.

26. A subscriber unit according to claim 21, wherein the processor element(s) select a radiation level that is a non-null level.

27. A subscriber unit according to claim 21, wherein the transmission characteristics include one or more of a signal amplitude and/or phase.

28. A subscriber unit according to claim 21, wherein the sequence of weight vectors share an amplitude value and have random phase values.

29. A subscriber unit according to claim 21, wherein the sequence of weight vectors are comprised of weight vectors which are orthogonal to one another.

30. A subscriber unit according to claim 29, wherein the orthogonal weight vectors share a common magnitude.

31. A subscriber unit according to claim 29, wherein the processor element(s) develop the orthogonal weight vectors from one or more of rows or columns of a complex valued Walsh-Hadamard matrix, rows or columns of a real valued Hadamard matrix, and/or a sequence whose elements are basis vectors of a Fourier transform.

32. A subscriber unit according to claim 21, wherein the sequence of weight vectors is comprised of weight vectors designed to provide a desirable radiation pattern within at least a sub-sector of an overall desired sector.

33. A subscriber unit according to claim 32, wherein the processor element(s) develop the sequence of weight vectors designed to provide a desirable radiation pattern based, at least in part, on information associated with known communication station(s) in the desired sector.

34. A subscriber unit according to claim 33, wherein the processor elements develop the sequence of weight vectors from spatial signature(s) associated with the known communication station(s).

35. A subscriber unit according to claim 33, wherein the processor element(s) develop the sequence of weight vectors using a vector quantization clustering process.

36. A subscriber unit according to claim 29, wherein the processor element(s) develop a plurality of signal processing procedures commensurate with the plurality of antennae comprising the antenna array.

37. A subscriber unit according to claim 21 wherein the signal is transmitted using a CDMA protocol.

38. A communication station comprising:

two or more antennas configured as an antenna array; and

processing element(s), coupled with the antenna array, to select a weight vector from a sequence of different weight vectors to develop a plurality of processing procedures, wherein elements of the weight vectors selectively modify one or more characteristics of transmission of the signal from each antenna in the antenna array and to iteratively process a signal through the plurality of signal processing procedures to generate a plurality of processed signals which, when sequentially transmitted via the antenna array, generate a desired radiation level at a number of locations within a desired sector.

39. A communication station according to claim 38, wherein the processing element(s) are comprised of one or more of an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable logic array (FPGA) and/or a microcontroller resident within the communication station.

40. A communication station according to claim 38, further comprising:

one or more transceivers, coupled with the antenna array and the processor element(s), to sequentially transmit each of the generated plurality of processed signals to achieve the desired radiation level at a number of locations in the desired sector during at least one of said sequential transmissions, wherein sequential transmission of the generated plurality of processed signals comprises a broadcast transmission.

41. A communication station according to claim 40, wherein the processor element(s) are integrated within one or more of the transceiver(s).

42. A communication station according to claim 40, wherein the transceiver comprises at least one processor element for each antenna within the antenna array.

43. A communication station according to claim 38, wherein the desired sector is comprised of a range of azimuths up to a complete range of azimuths of the antenna array.

44. A communication station according to claim 38, wherein the transmission characteristics include one or more of a signal amplitude and/or phase.

45. A communication station according to claim 38, wherein the sequence of weight vectors share an amplitude value and have random phase values.

46. A communication station according to claim 38, wherein the sequence of weight vectors are comprised of weight vectors which are orthogonal to one another.

47. A communication station according to claim 46, wherein the processor element(s) develop the orthogonal weight vectors from one or more of rows or columns of a complex valued Walsh-Hadamard matrix, rows or columns of a real valued Hadamard matrix, and/or a sequence whose elements are basis vectors of a Fourier transform.

48. A communication station according to claim 38, wherein the sequence of weight vectors is comprised of weight vectors designed to provide a desirable radiation pattern within at least a sub-sector of an overall desired sector.

49. A communication station according to claim 48, wherein the processor element(s) develop the sequence of weight vectors designed to provide a desirable radiation pattern based, at least in part, on information associated with known subscriber unit(s) in the desired sector.

50. A communication station according to claim 49, wherein the processor elements develop the sequence of weight vectors from spatial signature(s) associated with the known subscriber unit(s).

51. A communication station according to claim 49, wherein the processor element(s) develop the sequence of weight vectors using a vector quantization clustering process.

52. A communication station according to claim 51, wherein performing the vector quantization cluster process, the processor element(s):

assign an initial set of weight vectors as a current set of representative weight vectors;

combine each designed for subscriber unit weight vector with its nearest representative weight vector in the current set, according to some association criterion;

determine an average measure of a distance between each representative weight vector in the current set and all weight vectors combined with that representative weight vector;

replace each representative weight vector in the current set with a core weight vector for all the weight vectors that have been combined with that representative weight vector; and

iteratively repeat the combining, determining and replacing elements until a magnitude of the difference between the average measure in a present iteration and the average distance in the previous iteration is less than a threshold.

53. A communication station according to claim 38, wherein the processor element(s) develop a plurality of signal processing procedures commensurate with the plurality of antennae comprising the antenna array.

54. A communication station according to claim 38 wherein the signal is transmitted using a CDMA protocol.