Method and subscriber unit for performing an access procedure

• US 7,117,004 B2
• Filed: 06/14/2004
• Issued: 10/03/2006
• Est. Priority Date: 06/27/1996
• Status: Expired due to Fees

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Lomp, Gary R., Ozluturk, Fatih M.
• Primary Examiner(s): LE, LANA N
• Application Number:
  US10/866,851
• Publication Number:
  US 20040242259A1
• Time in Patent Office: 841 Days
• Field of Search: 455/522, 455/63.11, 455/69, 455/517, 455/507, 370/335, 370/342, 370/394, 370/395.2, 370/395.21, 370/514, 370/278, 370/491
• US Class Current: 455/522
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/70753 Partial phase search
• CPC Class Codes: H04B 1/70755 Setting of lock conditions, e.g. threshold
• CPC Class Codes: H04B 1/70758 Multimode search, i.e. using multiple search strategies
• CPC Class Codes: H04B 1/7077 Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
• CPC Class Codes: H04B 1/708 Parallel implementation
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 2201/7071 with dynamic control of receiver resources
• 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: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 52/60 using different transmission rates for TPC commands

Abstract

A base station for controlling transmission power during the establishment of a communication channel utilizes the reception of a short code during initial power ramp-up. The short code is a sequence for detection by the base station which has a much shorter period than a conventional access code. The ramp-up starts from a power level that is lower than the required power level for detection by the base station. The power of the short code is quickly increased until the signal is detected by the base station. Once the base station detects the short code, it transmits an indication that the short code has been detected.

Claims

1. A method for performing power control in a wireless code division multiple access communication system, the method comprising:

transmitting dynamically selected code signals at increasing power levels until an acknowledgement is received indicating that one of said dynamically selected code signals was detected, wherein the transmitted dynamically selected code signals carry no data; and

in response to detecting the acknowledgment, transmitting an access signal wherein the access signal is associated with the dynamically selected code signals and each of the dynamically selected code signals are shorter than the access signal.

2. A wireless code division multiple access subscriber unit, the subscriber unit comprising:

a transmitter configured such that a first code is transmitted at an initial power level wherein the first code is of a first code type and the transmitter further configured to repeatedly transmit dynamically selected codes of said first code type at increasing power levels wherein the transmitted codes of said first code type carry no data;

a receiver configured such that an acknowledgement is detected indicating a code of said first type was received; and

the transmitter configured such that in response to detecting the acknowledgement, a signal having a second code is transmitted to access a communication channel wherein the second code is associated with the first code.

3. A wireless code division multiple access base station, the base station comprising:

a receiver configured such that a code of a first code type is received, the received code carrying no data and being repeatedly transmitted at increasing power levels;

a transmitter configured such that an acknowledgement is transmitted indicating a code of said first type was received; and

the receiver configured such that a signal having a second code is received as part of an access procedure wherein the second code is associated with the first code.

4. A method for transmitting a communication in a wireless code division multiple access communication system, the method comprising:

repeatedly transmitting portions of the communication without a remainder of the communication wherein each subsequently transmitted portion is transmitted at an increased power level with respect to a prior transmitted portion, the transmitted portions not including any data;

detecting an acknowledgement indicating one of the transmitted portions was received;

transmitting the remainder of the communication in response to detecting the acknowledgement as part of an access procedure; and

wherein each of the portions include a code sequence.

5. A wireless code division multiple access subscriber unit, the subscriber unit comprising:

a transmitter configured such that portions of a communication are transmitted without a remainder of the communication wherein each subsequently transmitted portion is transmitted at an increased power level with respect to a prior transmitted portion, the portions not carrying any data;

a receiver configured such that an acknowledgement is detected indicating the transmitted portion was received; and

the transmitter configured such that the remainder of the communication is transmitted in response to detecting the acknowledgement wherein each of the portions include a code sequence.

6. A wireless code division multiple access base station, the base station comprising:

a receiver configured such that a portion of a communication is received without a remainder of the communication, the portion including no data;

a transmitter configured such that an acknowledgement is transmitted indicating the portion was received;

the receiver configured such that a remainder of the communication is received as part of an access procedure; and

wherein each of the portions include a code sequence.

7. A method for use in a code division multiple access subscriber unit for establishing communications between said subscriber unit and a base station, said method comprising:

transmitting a plurality of different codes by said subscriber unit to said base station wherein each different code is transmitted at increasing power levels;

receiving an acknowledgement by said subscriber unit from said base station and ceasing transmitting the plurality of different codes, said acknowledgement indicating to said subscriber unit that said base station has received at least one of said different codes; and

transmitting, in response to receipt of said acknowledgement, an access signal to facilitate communication initialization between said subscriber unit and said base station, said access signal as transmitted by said subscriber unit and said different codes as transmitted by said subscriber unit each being a function of a same code.

8. The method of claim 7 wherein each different code is sequentially transmitted at increasing power levels.

9. The method of claim 8 wherein the transmitting of the plurality of different codes ceases based on receipt of said acknowledgement.

10. The method of claim 7 wherein the transmitting of the plurality of different codes ceases based on receipt of said acknowledgement.

11. The method of claim 7 wherein said different codes have a bit length less than said access signal.

12. The method of claim 7 wherein said same code comprises a spreading code.

13. The method of claim 12 wherein said different codes as transmitted by said subscriber unit comprise a portion of said spreading code, and wherein said access signal as transmitted by said subscriber unit comprises at least a portion of said spreading code.

14. The method of claim 7 wherein said access signal is transmitted at a power level related to a last power level of said transmitting of said different codes.

15. The method of claim 14 wherein said power level related to said last power level of said transmitting said different codes is an increased power level with respect to said last power level of said transmitting said different codes.

16. The method of claim 7 wherein said transmitting said different codes comprises transmitting a first plurality of different codes derived from a first code before transmitting a second plurality of different codes derived from a second code different than the first code.

17. A method for establishing communications between a subscriber unit and a base station in a code division multiple access communications system, said method comprising:

transmitting less than a complete initialization code sequence from the subscriber unit to the base station at a first power level;

subsequently transmitting less than a complete initialization code sequence at an increased power level;

repeating said subsequently transmitting until an acknowledgement is received by said subscriber unit from said base station; and

transmitting, in response to receipt of said acknowledgement, enough of the initialization code sequence to facilitate communication initialization between said subscriber unit and said base station at a power level related to a last power level of said transmitting of said less than said complete initialization code sequence.

18. The method of claim 17 wherein the less than a complete initialization code sequence is dynamically selected for each subsequent transmission.

19. The method of claim 17 wherein the initialization code sequence includes a spreading code.

20. The method of claim 17 wherein the subsequently transmitted less than a complete initialization code sequence includes different portions of said complete initialization code sequence for at least one of each subsequent transmission.

21. A method for performing an access procedure in a code division multiple access subscriber unit for establishing communications between said subscriber unit and a base station, said method comprising:

transmitting a first code to be used by a base station in establishing communication between said base station and said subscriber unit at a first power level, said first code not providing data of said subscriber unit;

subsequently transmitting, with respect to said first code a same or a different code, at increasing power levels until an acknowledgement is received by the subscriber unit, reception of said acknowledgement by said subscriber unit indicating to said subscriber unit that the base station has detected transmission by the subscriber unit; and

transmitting, in response to receipt of said acknowledgement, a signal by said subscriber unit as part of the access procedure wherein the signal includes a second code that is associated with the same or different code.

22. The method of claim 21 wherein said same or different code is dynamically selected.

23. The method of claim 21 wherein said same or different code has a shorter bit length than the signal transmitted as part of the access procedure.

24. The method of claim 21 wherein said same or different code and said signal transmitted as part of the access procedure are a function of a single code.

25. The method of claim 21 wherein said single code includes a spreading code.

26. A method performed by a code division multiple access subscriber unit for establishing communications between the subscriber unit and a base station, the method comprising:

repeatedly transmitting codes of a first type until the subscriber unit receives an acknowledgement signal from the base station, each transmission of a code of the first type being at an increased power level with respect to a prior transmission of a code of the first type;

upon receiving the acknowledgement signal from the base station, transmitting a code of a second type,

wherein, the acknowledgement signal is an indication to the subscriber unit that the base station has received a code of the first type, and

wherein the subscriber unit sends data to the base station only after the base station has received a code of the first type.

27. The method of claim 26 wherein the code of the first type and the code of the second type are derived from a same code sequence.

28. The method of claim 27 wherein the same code sequence includes a spreading code.

29. The method of claim 26 wherein the code of the first type has a shorter bit length than the code of the second type.

30. A method performed by a code division multiple access subscriber unit for establishing communications between the subscriber unit and a base station, the method comprising:

(a) transmitting a code of a first type, wherein the code of the first type does not include data of the subscriber unit;

(b) determining if the subscriber unit has received an acknowledgement signal from the base station, the acknowledgement signal being an indication to the subscriber unit that the base station has received a code of the first type;

(c) repeating (a) at increasing power levels until the subscriber unit has received the acknowledgement signal; and

(d) transmitting a code of a second type after it is determined that the subscriber unit has received the acknowledgement signal.

31. The method of claim 30 wherein said code of a first type is a dynamically selected code associated with said code of a second type.

32. The method of claim 30 wherein said code of a first type is shorter than said code of a second type.

33. The method of claim 30 wherein said code of a first type carries no data.

34. A method for use in a code division multiple access subscriber unit for establishing communications between said subscriber unit and a base station, said method comprising:

(a) transmitting a first one of a plurality of different codes by said subscriber unit to said base station;

(b) if an acknowledgement is not received, transmitting another one of the plurality of different codes by said subscriber unit to said base station;

(c) repeating step (b) until an acknowledgement is received by said subscriber unit from said base station, said acknowledgement indicating to said subscriber unit that said base station has received at least one of said different codes; and

(d) transmitting, in response to receipt of said acknowledgement, an access signal to facilitate communication initialization between said subscriber unit and said base station, said access signal as transmitted by said subscriber unit and said different codes as transmitted by said subscriber unit each being a function of a same code.

35. The method of claim 34 wherein the transmitting of the plurality of different codes ceases based on receipt of said acknowledgement.

36. The method of claim 34 wherein the same code includes a spreading code.

37. The method of claim 34 wherein each of the plurality of different codes has a bit length less than said access signal.

38. A subscriber unit capable of establishing communications, said subscriber unit comprising:

a code generator for producing a plurality of different codes;

a transmitter for transmitting said produced plurality of different codes, wherein each different code is transmitted at increasing power levels;

a receiver for receiving an acknowledgement, said acknowledgement indicating that at least one of said different codes was received; and

wherein said code generator is operable in response to receipt of said acknowledgment by said receiver to produce an access signal and said transmitter transmits said access signal to facilitate communication initialization by said subscriber unit, said access signal and said different codes each being a function of a same code.

39. The subscriber unit of claim 38 wherein the transmitter sequentially transmits each different code at increasing power levels.

40. The subscriber unit of claim 38 wherein said different codes have a bit length less than said access signal.

41. The subscriber unit of claim 38 wherein said same code comprises a spreading code.

42. The subscriber unit of claim 41 wherein said different codes as transmitted by said subscriber unit comprise a portion of said spreading code, and wherein said access signal as transmitted by said subscriber unit comprises at least a portion of said spreading code.

43. The subscriber unit of claim 38 wherein said access signal is transmitted at a power level related to a last power level of said transmitting of said different codes.

44. The subscriber unit of claim 43 wherein said power level related to said last power level of said transmitting said different codes is an increased power level with respect to said last power level of said transmitting said different codes.

45. The subscriber unit of claim 38 wherein said transmitting said different codes comprises transmitting a first plurality of different codes derived from a first code before transmitting a second plurality of different codes derived from a second code different than the first code.

46. A subscriber unit operable to perform an access procedure in a code division multiple access system for establishing communications between said subscriber unit and a base station, said subscriber unit comprising:

a transmitter; and

a processor configured to control said transmitter to transmit a first code to be used by a base station in establishing communication between said base station and said subscriber unit at a first power level, said first code not providing data of said subscriber unit, wherein said processor is further configured to control said transmitter to subsequently transmit, with respect to said first code a same or a different code, at increasing power levels until an acknowledgement is received by the subscriber unit, reception of said acknowledgement by said subscriber unit indicating to said subscriber unit that the base station has detected transmission by the subscriber unit, and said processor is further configured to control said transmitter to transmit, in response to receipt of said acknowledgement, a signal by said subscriber unit as part of the access procedure wherein the signal includes a second code that is associated with the same or different code.

47. The subscriber unit of claim 46 wherein the processor is configured such that said same or a different code is dynamically selected.

48. The subscriber unit of claim 46 wherein said same or different code has a shorter bit length than the signal transmitted as part of the access procedure.

49. The subscriber unit of claim 46 wherein said same or different code and said signal transmitted as part of the access procedure are a function of a single code.

50. The subscriber unit of claim 49 wherein said single code includes a spreading code.

51. A subscriber unit operable to perform an access procedure for establishing communications between the subscriber unit and a base station, the subscriber unit comprising:

a transmitter configured to repeatedly transmit codes of a first type wherein each transmission of a code of the first type is transmitted at an increased power level with respect to a prior transmission of a code of the first type;

a receiver configured to receive an acknowledgement from the base station wherein the acknowledgement signal is an indication to the subscriber unit that the base station has received a code of the first type;

the transmitter further configured to transmit a code of a second type to said base station upon receipt by the receiver of said acknowledgement, and

wherein the code of a second type includes data.

52. The subscriber unit of claim 51 wherein the transmitter is configured such that the code of the first type and the code of the second type are derived from a same code sequence.

53. The subscriber unit of claim 52 wherein the same code sequence includes a spreading code.

54. The subscriber unit of claim 51 wherein the code of the first type has a shorter bit length than the code of the second type.

55. A subscriber unit operable to perform an access procedure for establishing communications, the subscriber unit comprising:

a transmitter configured to receive a code of a first type and to transmit the received code of the first type, wherein the transmitted code of the first type does not include data of the subscriber unit;

a receiver configured to receive an acknowledgement signal, the acknowledgement signal being an indication to the subscriber unit that a code of the first type was received;

the transmitter further configured to repeatedly receive a code of the first type and to transmit each received code of the first type until the receiver receives the acknowledgement signal;

wherein the received transmitted codes of a first type are transmitted at increasing power levels until the receiver has received the acknowledgement signal; and

the transmitter, in response to the receiver receiving an acknowledgement, further configured to receive a code of a second type and to transmit the code of the second type.

56. The subscriber unit of claim 55 wherein the transmitter is configured such that said codes of a first type are dynamically selected codes associated with said code of a second type.

57. The subscriber unit of claim 55 wherein each of the received transmitted codes of a first type is shorter than said code of a second type.

58. The subscriber unit of claim 55 wherein said received transmitted codes of a first type carry no data.

59. A subscriber unit for performing an access procedure for establishing communications between said subscriber unit and a base station, said subscriber unit comprising:

a processor configured to control a transmitter such that the transmitter transmits a first one of a plurality of different codes by said subscriber unit to said base station;

a receiver configured to receive an acknowledgement wherein if said acknowledgement is not received, the processor configured to control the transmitter such that the transmitter transmits another one of the plurality of different codes by said subscriber unit to said base station;

the processor configured to control said transmitter such that said transmitter repeats the transmitting of another one of the plurality of different codes until said acknowledgement is received by said subscriber unit from said base station, said acknowledgement indicating to said subscriber unit that said base station has received at least one of said different codes; and

said processor configured to control the transmitter such that the transmitter transmits, in response to receipt of said acknowledgement, an access signal to facilitate communication initialization between said subscriber, unit and said base station, said access signal as transmitted by said subscriber unit and said different codes as transmitted by said subscriber unit each being a function of a same code.

60. The subscriber unit of claim 59 wherein the processor is configured to control said transmitter such that the transmitting of the plurality of different codes ceases based on receipt of said acknowledgement.

61. The subscriber unit of claim 59 wherein the same code includes a spreading code.

62. The subscriber unit of claim 59 wherein each of the plurality of different codes has a bit length less than said access signal.

63. A subscriber unit for performing an access procedure for establishing communications between a subscriber unit and a base station in a code division multiple access communications system, said subscriber unit comprising:

a transmitting arrangement configured to control a transmitter such that said transmitter transmits less than a complete initialization code sequence from the subscriber unit to the base station at a first power level;

the transmitting arrangement further configured to subsequently transmit less than a complete initialization code sequence at an increased power level and configured to repeat said subsequent transmitting until an acknowledgement is received by a receiver of said subscriber unit from said base station; and

the transmitting arrangement further configured to transmit, in response to receipt of said acknowledgement, enough of the initialization code sequence to facilitate communication initialization between said subscriber unit and said base station at a power level related to a last power level of said transmitting of said less than said complete initialization code sequence.

64. The subscriber unit of claim 63 wherein the transmitting arrangement is configured such that the less than a complete initialization code sequence is dynamically selected for each subsequent transmission.

65. The subscriber unit of claim 63 wherein the initialization code sequence includes a spreading code.

66. The subscriber unit of claim 63 wherein the subsequently transmitted less than a complete initialization code sequence includes different portions of said complete initialization code sequence for at least one of each subsequent transmission.