Data burst randomizer

• US 5,535,239 A
• Filed: 08/16/1994
• Issued: 07/09/1996
• Est. Priority Date: 06/25/1990
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Kindred, Daniel R., Rueth, Timothy I., Jou, Yu-Cheun, Padovani, Roberto, McDonough, John G.
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US08/291,231
• Time in Patent Office: 693 Days
• Field of Search: 375/168, 375/200-210, 375/309, 380/34, 380/28, 365/233, 370/18, 370/19, 370/20, 370/58.1, 370/58.2, 370/60, 370/68, 370/91, 370/94.1, 370/95.3
• US Class Current: 370/209
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/70757 with increased resolution, i.e. higher than half a chip H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 7/2618 using hybrid code-time division multiple access [CDMA-TDMA]
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04B 7/2637 for logical channel control
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04J 13/10 Code generation
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04J 3/1688 the demands of the users being taken into account after redundancy removal, e.g. by predictive coding, by variable sampling reducing bandwidth of signals in general H04B1/66; in PCM-systems H04B14/046; removal of redundancy in telegraph communication H03M7/30
• CPC Class Codes: H04J 3/22 in which the sources have different rates or codes simultaneous speech and digital data or video transmission H04M11/06; see provisional also H04J3/16
• CPC Class Codes: H04L 1/0006 by adapting the transmission format
• CPC Class Codes: H04L 1/0065 Serial concatenated codes
• CPC Class Codes: H04L 1/0068 by puncturing
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 23/02 adapted for orthogonal signalling
• CPC Class Codes: H04L 5/02 Channels characterised by the type of signal
• CPC Class Codes: H04L 5/12 : the signals being represented by different phase modulations of a single carrier
• CPC Class Codes: H04W 52/26 : using transmission rate or quality of service QoS [Quality of Service]

Abstract

A method and system, for use in a communication system in which data is transmitted in data frames of a predetermined time duration, for the positioning of the data within the data frames for transmission. A computation circuit computes according to the deterministic code a pseudorandom position for the data within each data frame. A positioning circuit positions the data within each data frame in the computed position.

Claims

1. A spread spectrum modulator for modulating variable rate digital data generated in data frames of a predetermined time duration with each frame of data having a number of data bits which is a predetermined multiple of data bits in a frame of a least number of data bits, comprising:

encoder means for receiving and convolutionally encoding a frame of variable rate digital data, and generating a frame of symbol data with said symbol data in a first ordered sequence;

interleaver means for reordering said symbol data in said frame and generating said frame of symbol data in a second ordered sequence, and if said frame of symbol data corresponds to a frame of variable rate digital data having a number of data bits less than a frame maximum of data bits said interleaver means generating said symbol data and a predetermined number of repeats of said symbol data in said frame of symbol data in said second ordered sequence to generate a predetermined frame maximum number of symbols in said frame of sequence symbol data in said second ordered sequence;

symbol encoder means for determining from a value of each one of consecutive portions of said frame of symbol data in said second ordered sequence an modulation symbol of a set of modulation symbols, and generating an output frame of function data;

first spreading means for generating a first pseudorandom noise (PN) code;

first combining means for combining said frame of modulation symbol data and said first PN code, and generating an output frame of first PN spread data;

randomizer logic means responsive to said first PN code and an indication of a data rate of said frame variable rate digital data for generating a mask signal; and

filter means for responsive to said mask signal for filtering out portions of said first PN spread data in said frame of first PN spread data.

2. The modulator of claim 1 further comprising:

second and third spreading means for respectively generating second and third PN codes;

second combining means for receiving and combining said second PN code with said frame of first PN spread data for generating a frame of second PN spread data;

third combining means for combining said third PN code with said frame of first PN spread data and generating a frame of third PN spread data; and

wherein said filter means comprises first and second finite impulse response (FIR) filter means for respectively digitally filtering out portions of said frames of second and third PN spread data.

3. The modulator of claim 2 wherein said first PN code is of a first code length and said second and third PN codes are of a second code length, with said first code length being substantially greater in length than said second code length.

4. The modulator of claim 1 wherein said symbols are Walsh functions.

5. The modulator of claim 4 wherein said encoder means is a convolutional encoder.

6. The modulator of claim 5 wherein said symbol encoder means comprises a 64-ary Walsh function encoder.

7. The modulator of claim 1 wherein said randomizer logic means is further for generating an additional mask signal for controlling a power amplifier.

8. A spread spectrum transmitter for modulation and transmission of a data packet of a variable number of bits in a data frame of a predetermined data capacity, comprising:

interleaver means for receiving said data packet, and if said variable rate data packet is less than said frame data capacity ordering the bits of said data packet in said data frame in accordance with a pseudorandom ordering signal to generate said data frame;

randomizing logic for generating, in accordance with a pseudorandom code, said pseudorandom ordering signal;

spread spectrum modulation means for receiving said data frame and spread spectrum modulating said data frame; and

transmitter for transmitting said spread spectrum modulated data frame.

9. The apparatus of claim 8 wherein said randomizing logic is responsive to the data rate of said data packet.

10. The apparatus of claim 8 wherein said transmitter is responsive to said randomizing logic for selectively gating the transmission of portions of said spread spectrum modulated data frame.

11. The apparatus of claim 8 wherein said spread spectrum modulation means is responsive to a long code for determining a corresponding spread spectrum format.

12. The apparatus of claim 11 wherein said randomizing logic is responsive to said long code for determining said pseudorandom code.

13. The apparatus of claim 8 further comprising a convolutional encoder for encoding said data packet.

14. A spread spectrum transmitter for modulation and transmission of a data packet of a variable number of bits in a data frame of a predetermined data capacity, comprising:

interleaver means for receiving said data packet, and if said data packet is less than said data capacity generating repeated copies of bits in said data packet and inserting said copies in said data frame;

spread spectrum modulation means for spread spectrum modulating said data frame;

randomizing logic for generating, in accordance with a pseudorandom code, a pseudorandom gating signal; and

transmitter for selectively transmitting bits of said data frame in accordance with said pseudorandom gating signal.

15. The apparatus of claim 14 wherein said transmitter transmits only a single instance of each of said bits of said data packet.

16. The apparatus of claim 14 wherein said randomizing logic is responsive to the data rate of said data packet.

17. The apparatus of claim 14 wherein said spread spectrum modulation means is responsive to a long code for determining a corresponding spread spectrum format.

18. The apparatus of claim 17 wherein said randomizing logic is responsive to said long code for determining said pseudorandom code.

19. A spread spectrum transmitter for modulation and transmission of a data packet of a variable number of data packet bits in a data frame of a predetermined data capacity, comprising:

interleaver means for receiving said data packet, and if said data packet is less than said data capacity generating a copy of said data packet bits in said data packet and inserting said copy of said data packet bits in said data frame;

filtering means for receiving said data frame and filtering out a portion of said data packet bits and said copy of said data packet bits from said data frame in accordance with a pseudorandom filtering signal;

spreading means for spread spectrum modulating said filtered data frame; and

transmitter means for transmitting said spread spectrum modulated data frame.

20. The apparatus of claim 19 wherein the filter response of said filtering means is determined by a set of variable coefficients.

21. The apparatus of claim 20 wherein said filter coefficients are determined in accordance with said pseudorandom filtering signal.

22. The apparatus of claim 19 wherein said filtering means generates a filtered data frame consisting of only a single instance of said data packet bits.

23. The apparatus of claim 19 wherein said filtering means is a finite impulse response filter.

24. The apparatus of claim 19 wherein said randomizing logic is further for generating a pseudorandom gating signal and wherein said transmitter is responsive to said pseudorandom gating signal for selectively transmitting bits of said spread spectrum modulated data frame.

25. In a spread spectrum transmitter, a method for spread spectrum modulation and transmission of a data packet of a variable number of bits in a data frame of a predetermined data capacity, comprising:

receiving said data packet;

ordering the bits of said data packet in said data frame in accordance with a pseudorandom ordering signal if said variable rate data packet is less than said frame data capacity;

generating in accordance with a pseudorandom code, said pseudorandom ordering signal;

spread spectrum modulating said data frame; and

transmitting said spread spectrum modulated data frame.

26. The method of claim 25 wherein said step of generating said pseudorandom ordering signal is responsive to the data rate of said data packet.

27. The method of claim 25 wherein said step of transmitting is responsive to a pseudorandom gating signal for selectively transmitting portions of said spread spectrum modulated data frame.

28. The method of claim 25 wherein said step of spread spectrum modulating is responsive to a long code for determining a corresponding spread spectrum format.

29. The apparatus of claim 28 wherein said step of generating said pseudorandom ordering signal is responsive to said long code.

30. In a spread spectrum transmitter, a method for spread spectrum modulation and transmission of a data packet of a variable number of bits in a data frame of a predetermined frame data capacity, comprising:

receiving said data packet;

generating at least one copy of said bits in said data packet if said variable rate data packet is less than said frame data capacity;

combining said at least one copy of said data packet bits and said data packet bits to generate said data frame;

spread spectrum modulating said data frame;

generating, in accordance with a pseudorandom code, a pseudorandom gating signal; and

selectively transmitting bits of said data frame in accordance with said pseudorandom gating signal.

31. The method of claim 30, wherein said step of selectively transmitting transmits only a single instance of each of said bits of said data packet.

32. The method of claim 30 wherein said step of generating said pseudorandom gating signal is responsive to the data rate of said data packet.

33. The method of claim 30 wherein said step of spread spectrum modulating is responsive to a long code for determining a corresponding spread spectrum format.

34. The method of claim 33 wherein said step of generating said pseudorandom gating signal is responsive to said long code for determining said pseudorandom code.

35. In a spread spectrum transmitter, a method for spread spectrum modulation and transmission of a data packet of a variable number of bits in a data frame of a predetermined frame data capacity, comprising the steps of:

receiving said data packet;

generating an additional set of said bits in said data packet if said variable rate data packet is less than said frame data capacity;

combining said additional set of said data packet bits and said data packet bits to generate said data frame;

filtering out a sub-set of bits of said data packet bits and said additional set of of said data packet bits from said data frame in accordance with a pseudorandom filtering signal;

generating said pseudorandom filtering signal in accordance with a pseudorandom code;

spread spectrum modulating said filtered data frame; and

transmitting said spread spectrum modulated data frame.

36. The method of claim 35 wherein said step of filtering is responsive to a set of variable filter coefficients.

37. The method of claim 36 wherein said filter coefficient values are determined in accordance with said pseudorandom filtering signal.

38. The method of claim 35 wherein said step of filtering generates a filtered data frame consisting of only a single instance of each of said data packet bits.

39. The method of claim 35 wherein said step of filtering comprises passing said data frame through a finite impulse response filter.

40. A spread spectrum transmitter for spread spectrum modulation and transmission of a data packet of a variable number of bits in a data frame of a predetermined data capacity, comprising:

an interleaver having a first input for receiving said data packet and an output for generating said data frame and having a second input;

a data burst randomizer having an output coupled to said interleaver second input;

a spread spectrum modulator having an input coupled to said interleaver output and having an output; and

a transmitter having an input coupled to said spread spectrum modulator output and having an output.

41. The apparatus of claim 40 wherein said data burst randomizer has an input for receiving a signal indicative of the data rate of said data packet.

42. The apparatus of claim 40 wherein said data burst randomizer has a second output and wherein said transmitter has a second input coupled to said data burst randomizer second output.

43. The apparatus of claim 40, wherein said spread spectrum modulator has a second input for receiving a long code signal.

44. The apparatus of claim 43 wherein said data burst randomizer has input for receiving said long code signal.

45. A spread spectrum transmitter for modulation and transmission of a data packet of a variable number of bits in a data frame of a predetermined frame data capacity, comprising:

an interleaver having an input port for receiving said data packet and having an output port to generate said data frame consisting of a first instance of said bits of said data packet and a second instance of said bits of said data packet;

a spread spectrum modulator having an input coupled to said interleaver output and having an output;

a data burst randomizer having an output; and

transmitter having a first input coupled to said spread spectrum modulator output and a second input coupled to said data burst randomizer output and having an output.

46. The apparatus of claim 45 wherein said transmitter output generates only a single instance of each of said bits of said data packet.

47. The apparatus of claim 45 wherein said data burst randomizer has an input for receiving a signal indicative of the data rate of said data packet.

48. The apparatus of claim 45 wherein said spread spectrum modulator has an input for receiving a long code.

49. The apparatus of claim 48 wherein said data burst randomizer has an input for receiving said long code signal.

50. A spread spectrum transmitter for modulation and transmission of a data packet of a variable number of bits in a data frame of a predetermined data capacity, comprising:

an interleaver having an input for receiving said data packet and output for generating a data frame comprising first instance of said data packet bits and a second instance of said data packet bits;

a data burst randomizer having an output;

a filter having a first input coupled to said interleaver output and a second input coupled to said data burst randomizer output and having an output;

a spread spectrum modulator coupled to said filter output and having an output; and

transmitter means having an input coupled to said spread spectrum modulator output and having an output.

51. The apparatus of claim 50 wherein the filter response of said filter means is determined by a set of variable coefficients.

52. The apparatus of claim 50 wherein said filter generates a filtered data frame consisting of a single copy of said data packet bits.

53. The apparatus of claim 50 wherein said filter is a finite impulse response filter.

54. The apparatus of claim 50 wherein said data burst randomizer has a second output for generating a pseudorandom gating signal and wherein said transmitter has a second input coupled to said second data burst randomizer output.

55. A spread spectrum modulator for modulating variable rate digital data generated in data frames of a predetermined time duration with each frame of data having a number of data bits which is a predetermined multiple of data bits in a frame of a least number of data bits, comprising:

an encoder for receiving and convolutionally encoding a frame of variable rate digital data, and generating a frame of symbol data with said symbol data in a first ordered sequence;

an interleaver for reordering said symbol data in said frame and generating said frame of symbol data in a second ordered sequence, wherein if said frame of symbol data corresponds to a frame of variable rate digital data having a number of data bits less than a frame maximum of data bits, said interleaver means generating said symbol data and a predetermined number of repeats of said symbol data in said frame of symbol data in said second ordered sequence to generate a predetermined frame maximum number of symbols in said frame of sequence symbol data in said second ordered sequence;

a symbol encoder for determining from a value of each one of consecutive portions of said frame of symbol data in said second ordered sequence an modulation symbol of a set of modulation symbols, and generating an output frame of function data;

a PN code generator for generating a first pseudorandom noise (PN) code;

a first combiner for combining said frame of modulation symbol data and said first PN code, and generating an output frame of first PN spread data;

a randomizer logic responsive to said first PN code and an indication of a data rate of said frame variable rate digital data for generating a mask signal; and

a filter for responsive to said mask signal for filtering out portions of said first PN spread data in said frame of first PN spread data.

56. The modulator of claim 55 further comprising:

a second PN code generator for generating a second PN code;

a third PN code generator for generating a third PN code;

second combiner for receiving and combining said second PN code with said frame of first PN spread data for generating a frame of second PN spread data;

third combiner for combining said third PN code with said frame of first PN spread data and generating a frame of third PN spread data; and

wherein said filter comprises first and second finite impulse response (FIR) filter means for respectively digitally filtering out portions of said frames of second and third PN spread data.

57. The modulator of claim 56 wherein said first PN code is of a first code length and said second and third PN codes are of a second code length, with said first code length being substantially greater in length than said second code length.

58. The modulator of claim 55 wherein said symbols are Walsh functions.

59. The modulator of claim 58 wherein said encoder is a convolutional encoder.

60. The modulator of claim 59 wherein said symbol encoder is a 64-ary Walsh function encoder.

61. The modulator of claim 55 wherein said randomizer logic means is further for generating an additional mask signal for controlling a power amplifier.

62. A spread spectrum transmitter for modulation and transmission of a data packet of a variable number of bits in a data frame of a predetermined frame data capacity, comprising:

interleaver means for receiving said data packet, and if said variable rate data packet has fewer bits than said frame data capacity generating additional sets of said bits in said data packet to generate a repetition frame;

spreader means for spread spectrum spreading said repetition frame thereby generating a spread spectrum modulated frame; and

transmitter means for selectively transmitting a sub-set of bits of said spread spectrum modulated data frame.

63. The apparatus of claim 62 wherein said sub-set of bits contains only a single set of said data packet bits.

64. The apparatus of claim 62 wherein said transmitter is responsive to the data rate of said data packet.

65. The apparatus of claim 62 wherein said spreading means is responsive to a long code signal.

66. The apparatus of claim 65 wherein said transmitter means is responsive to said long code signal.

67. A spread spectrum transmitter for modulation and transmission of a data packet of a variable number of data packet bits in a data frame of a predetermined frame data capacity, comprising:

an interleaver having an input port for receiving said data packet and having an output port for generating at least one copy of said data packet bits;

a spread spectrum modulator having an input port coupled to said interleaver output port and having an output port; and

a gating transmitter having an input port coupled to said spread spectrum spreader output port and having an output port.

68. The apparatus of claim 67 wherein said gating transmitted transmits only a single instance of said data packet bits.

69. The apparatus of claim 67 wherein said transmitter has a second input port for receiving a signal indicative of the data rate of said data packet.

70. The apparatus of claim 67 wherein said spread spectrum spreader has a second input for receiving a signal indicative of a long code signal.

71. The apparatus of claim 70 wherein said transmitter has a second input for receiving said long code signal.

72. In a spread spectrum transmitter, a method for transmitting data via a data frame having a maximum data capacity and a transmission time period comprising the steps of:

(a) receiving a data packet; and

(b) transmitting portions of said data packet at pseudo-random times within said transmission time period until a single copy of said data packet has been transmitted.

73. The method for transmitting data as set forth in claim 72 wherein step (b) is comprised the steps of:

(b.1) transmitting said data packet at all times if said data packet has a first amount of data equal to said maximum data capacity;

(b.2) transmitting said data packet during a first sub-set of time slots pseudo randomly chosen from a set of time slots if said data packet has a second amount of data that is less than said maximum data capacity; and

(b.3) transmitting said data packet during a second sub-set of time slots that is a sub-set of said first sub-set of time slots if said data packet has a third amount of data that is less than said second amount of data.

74. The method for transmitting data as set forth in claim 73 wherein said first and second set of time slots are chosen a function of a long code also used for spreading said data frame.

75. The method for transmitting data as set forth in claim 72 wherein step (b) is comprised of the steps of:

(b.1) generating sufficient copies of said data packet to generate an amount of data equal to said maximum data capacity;

(b.2) dividing each instance of said data packet into identical sets of slots;

(b.3) pseudo-randomly selecting a set of slots from said identical sets of slots that cumulatively contain only one instance of said data packet; and

(b.4) transmitting said set of slots.

76. The method for transmitting data as set forth in claim 75 wherein said set of slots contain a first set of slots if said data packet contains a first amount of data, and said set of slots contain said first set of slots and a second set of slots if said packet contains a second amount of data that is larger than said first amount of data, and said set of slots contains said first set of slots and a third set of slots if said packet contains a third amount of data that is larger than said second amount of data.