CDMA receiver comprising a synchronous timing notifying section capable of reaching low consumption of current

• US 6,574,200 B1
• Filed: 08/31/1999
• Issued: 06/03/2003
• Est. Priority Date: 09/01/1998
• Status: Expired due to Term

• Current Assignee: Lenovo Innovations Ltd Hong Kong (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Tsumura, Soichi
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): WEST, LEWIS G
• Application Number:
  US09/387,296
• Time in Patent Office: 1,372 Days
• Field of Search: 370/311, 455/572, 455/574, 455/343, 455/550, 455/255, 455/256
• US Class Current: 370/311
• CPC Class Codes: H04B 1/70758 Multimode search, i.e. using multiple search strategies
• CPC Class Codes: H04B 2201/70709 with discontinuous detection
• CPC Class Codes: H04W 52/0274 by switching on or off the equipment or parts thereof
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In a CDMA receiver for intermittently receiving a spread spectrum received signal using a despreading code and comprising a high-resolution time reference generating section and a low-resolution time reference generating section, a state control section puts, for substantially a reception operation stop time interval, the CDMA receiver into a cold standby state where the high-resolution time reference generating section does not operate while the low-resolution time reference generating section operates. On or immediately before a reception return time instant, the state control section puts the CDMA receiver into a hot standby state where the high-resolution time reference generating section operates.

Claims

1. A code division multiple access (CDMA) receiver for intermittently receiving a spread spectrum received signal using a despreading code having a chip duration, said CDMA receiver being alternatively put into a reception operation state and reception operation stop state for an intermittent reception state, the reception operation stop state continuing for a reception operation stop time interval between a reception stop starting time instant and a reception return time instant, said CDMA receiver comprising:

a high-resolution time reference generating section for generating a high-resolution timing signal having a high-resolution period which is shorter than the chip duration;

a low-resolution time reference generating section for generating a low-resolution timing signal having a low-resolution period which is longer than the high-resolution period;

a state control section, connected to said high resolution time reference generating section, for putting, for substantially the operation stop time interval, said CDMA receiver into a cold standby state where said high-resolution time reference generating section does not operate while said low-resolution time reference generating section operates, said state control section putting, on or immediately before the reception return time instant, said CDMA receiver into a hot standby state where said high-resolution time reference generating section operates;

said CDMA receiver further comprising a demodulating section for demodulating the spread spectrum received signal using the despreading code to produce a demodulated signal and a synchronous timing generating section, connected to said demodulating section, for generating a synchronous timing signal for synchronizing said despreading code with the spread spectrum received signal, wherein said state control section comprises;

a time interval measuring section, connected to said high-resolution time reference generating section and said low-resolution time reference generating section, for measuring the reception operation stop time interval by using a combination of a multiple of the low-resolution period and a multiple of the high-resolution period, said time interval measuring section producing an operation control trigger signal and a despreading code timing adjustment signal in response thereto;

an operation control section, connected to said time interval measuring section and said high-resolution time reference generating section, for controlling operation of said high-resolution time reference generating section in response to the operation control trigger signal; and

a notification signal producing section, connected to said time interval measuring section and said synchronous timing generating section, for notifying said synchronous timing generating section of a synchronous timing notification signal in response to the despreading code timing adjustment signal.

2. A CDMA receiver as claimed in claim 1, wherein said time interval measuring section holds a low-resolution use time interval for which said low-resolution time reference generating section is used, the low-resolution use time interval including a time duration for which said CDMA receiver is put into the cold standby, the low-resolution use time interval being k times as large as the low-resolution period, where k represents a predetermined positive integer which is not less than two, said time interval measuring section measuring, in synchronism with the high-resolution timing signal, a starting difference time interval between the reception stop starting time instant and a starting time instant of the low-resolution use time interval, said time interval measuring section calculating a high-resolution compensation time interval on the basis of the reception operation stop time interval, the starting difference time interval, and the low-resolution use time interval, said high-resolution compensation time interval being a time duration for which said CDMA receiver is put into the hot standby state, said time interval measuring section producing the operation control trigger signal indicative of operation stop of said high-resolution time reference generating section at a time when said CDMA receiver is put into the cold standby state, said time interval measuring section producing the operation control trigger signal indicative of operation start of said high-resolution time reference generating section at a time when said CDMA receiver is put into the hot standby state,

said operation control section making, in response to the operation control trigger signal indicative of the operation stop of said high-resolution time reference generating section, said high-resolution time reference generating section stop operation thereof, said operation control section making, in response to the operation control trigger signal indicative of the operation start of said high-resolution time reference generating section, said high-resolution time reference generating section restart operation thereof.

3. A CDMA receiver as claimed in claim 2, wherein said synchronous timing generating section supplies said notification signal producing section with a current synchronous timing signal indicative of a period of the synchronous timing signal,

said notification signal producing section supplying, in response to the current synchronous timing signal, said time interval measuring section with a despreading code timing signal,

said time measuring section carrying out a measurement operation of the starting difference time interval in response to the despreading code timing signal.

4. A CDMA receiver as claimed in claim 3, wherein said time measuring section comprises:

a phase measurement section, connected to said high-resolution time reference generating section, said low-resolution time reference generating section, and said notification signal producing section, for measuring, in synchronism with the high-resolution timing signal, the starting difference time interval on the basis of the despreading code timing signal and the low-resolution timing signal, said phase measurement section calculating the high-resolution compensation time interval using the reception operation stop time interval, the starting difference time interval, and the low-resolution use time interval, said phase measurement section producing a phase measurement result signal indicative of the high-resolution compensation time interval; and

a timing generating section, connected to said high-resolution time reference generating section, said low-resolution time reference generating section, said phase measurement section, said operation control section, and said notification signal producing section, for counting, in response to the phase measurement result signal, timings for production of the operation control trigger signal and the despreading code timing adjustment signal on the basis of the low-resolution timing signal and the high-resolution timing signal, said timing generating section supplying said operation control section and said notification signal producing section with the operation control trigger signal and the despreading code timing adjustment signal, respectively.

5. A CDMA receiver as claimed in claim 4, wherein said phase measurement section comprises:

a starting difference time interval timer, connected to said high-resolution time reference generating section, said low-resolution time reference generating section, and said notification signal producing section, for timing, in synchronism with the high-resolution timing signal, the starting difference time interval between the despreading code timing signal and the starting time instant of the low-resolution use time interval in response to the low-resolution timing signal and the despreading code timing signal;

a calculating circuit, connected to said starting difference time interval timer, for calculating the high-resolution compensation time interval using the reception operation stop time interval, the starting difference time interval, and the low-resolution use time interval; and

a register, connected to said calculation circuit, for holding the high-resolution compensation time interval as a held time interval, said register producing the phase measurement result signal indicative of the held time interval.

6. A CDMA receiver as claimed in claim 5, wherein said timing generating section comprises:

a low-resolution use time interval timer, connected to said low-resolution time reference time generating section, for timing, in synchronism with the low-resolution timing signal, a first elapsed time duration from the starting time instant of the low-resolution use time interval, said low-resolution use time interval timer producing a first time-out signal when the first elapsed time duration amounts to the low-resolution use time interval;

a trigger producing circuit, connected to said low-resolution use time interval timer and said phase measurement section, for producing the operation control trigger signal indicative of the operation stop of said high-resolution time reference generating section in response to the phase measurement result signal, said trigger producing circuit producing the operation control trigger signal indicative of the operation start of said high-resolution time reference generating section in response to the first time-out signal; and

a high-resolution compensation time interval timer, connected to said low-resolution use time interval timer, said phase measurement section, and said high-resolution time reference generating section, for timing, in synchronism with the high-resolution timing signal, a second elapsed time duration from an expiry time instant of the low-resolution use time interval, said high-resolution compensation time interval timer producing a second time-out signal as the despreading code timing adjustment signal when the second elapsed time duration amounts to the high-resolution compensation time interval.

7. A CDMA receiver as claimed in claim 5, wherein said starting difference time interval timer comprises an up-counter for starting, in synchronism with the high-resolution timing signal, an up-count operation in response to an edge of the low-resolution timing signal and for stopping the up-count operation in response to the despreading code timing signal, said up-counter producing an up-counted value indicative of the starting difference time interval,

said calculation circuit calculating a calculated value indicative of the high-resolution compensation time interval using the reception operation stop time interval, the starting difference time interval, the low-resolution use time interval, and the high-resolution period,

said register holding the calculated value as a held value to produce the held value as the phase measurement result signal.

8. A CDMA receiver as claimed in claim 7, wherein said timing generating section comprises:

a first down-counter, connected to said low-resolution time reference time generating section and provided with the predetermined positive integer, for carrying out, in synchronism with the low-resolution timing signal, a first down-count operation on a first down-counted value from the predetermined positive integer, said first down-counter producing a first countdown end signal when the first down-counted value is equal to zero;

a trigger producing circuit, connected to said first down-counter and said phase measurement section, for producing the operation control trigger signal indicative of the operation stop of said-high-resolution time reference generating section in response to the phase measurement result signal, said trigger producing circuit producing the operation control trigger signal indicative of the operation start of said high-resolution time reference generating section in response to the first countdown end signal; and

a second down-counter, connected to said first down-counter, said phase measurement section, and said high-resolution time reference time generating section, for carrying out, in synchronism with the high-resolution timing signal, a second down-count operation on a second down-counted value from the calculated value in response to the first countdown end signal, said second down-counter producing a second countdown end signal as the despreading code timing adjustment signal when the second down-counted value is equal to zero.

9. A CDMA receiver as claimed in claim 8, wherein said predetermined positive integer k is represented by an expression as follows:

10. A CDMA receiver as claimed in claim 9, wherein said low-resolution use time interval (kT_L) is a time interval obtained by multiplying the predetermined positive integer (k) by the low-resolution period (T_L).

11. A CDMA receiver as claimed in claim 10, wherein said starting difference time interval (mT_H) is a time interval obtained by multiplying the up-counted value (m) by the high-resolution period (T_H).

12. A CDMA receiver as claimed in claim 11, wherein said calculated value depicted at n is represented by an expression as follows:

13. A CDMA receiver as claimed in claim 12, wherein said high-resolution compensation time interval (nT_H) is a time interval obtained by multiplying the calculated value (n) by the high-resolution period (T_H).

14. A CDMA receiver as claimed in claim 10, wherein said low-resolution period (T_L) is selected so as to satisfy a relationship among the reception operation stop time interval (Ts), the chip duration depicted at Tc, the predetermined positive integer (k), and the low-resolution period (T_L) as follow:

15. A CDMA receiver as claimed in claim 5, wherein said starting difference time interval timer comprises an up-counter for starting, in synchronism with the high-resolution timing signal, an up-count operation in response to the despreading code timing signal and for stopping the up-count operation in response to an edge of the low-resolution timing signal, said up-counter producing an up-counted value indicative of the starting difference time interval,

said calculation circuit calculating a calculated value indicative of the high-resolution compensation time interval using the reception operation stop time interval, the starting difference time interval, the low-resolution use time interval, and the high-resolution period,

said register holding the calculated value as a held value to produce the held value as the phase measurement result signal.

16. A CDMA receiver as claimed in claim 15, wherein said timing generating section comprises:

a first down-counter, connected to said low-resolution time reference time generating section and given with the predetermined positive integer, for carrying out, in synchronism with the low-resolution timing signal, a first down-count operation on a first down-counted value from the predetermined positive integer, said first down-counter producing a first countdown end signal when the first down-counted value is equal to zero;

a trigger producing circuit, connected to said first down-counter and said phase measurement section, for producing the operation control trigger signal indicative of the operation stop of said high-resolution time reference generating section in response to the phase measurement result signal, said trigger producing circuit producing the operation control trigger signal indicative of the operation start of said high-resolution time reference generating section in response to the first countdown end signal; and

a second down-counter, connected to said first down-counter, said phase measurement section, and said high-resolution time reference time generating section, for carrying out, in synchronism with the high-resolution timing signal, a second down-count operation on a second down-counted value from the calculated value in response to the first countdown end signal, said second down-counter producing a second countdown end signal as the despreading code timing adjustment signal when the second down-counted value is equal to zero.

17. A CDMA receiver as claimed in claim 15, wherein said predetermined positive integer k is represented by an expression as follows:

18. A CDMA receiver as claimed in claim 17, wherein said low-resolution use time interval (kT_L) is a time interval obtained by multiplying the predetermined positive integer (k) by the low-resolution period (T_L).

19. A CDMA receiver as claimed in claim 18, wherein said starting difference time interval (mT_H) is a time interval obtained by multiplying the up-counted value (m) by the high-resolution period (T_H).

20. A CDMA receiver as claimed in claim 19, wherein said calculated value depicted at n is represented by an expression as follows:

21. A CDMA receiver as claimed in claim 20, wherein said high-resolution compensation time interval (nT_H) is a time interval obtained by multiplying the calculated value (n) by the high-resolution period (T_H).

22. A CDMA receiver as claimed in claim 18, wherein said low-resolution period (T_L) is selected so as to satisfy a relationship among the reception operation stop time interval (Ts), the chip duration (Tc), the predetermined positive integer (k), and the low-resolution period (T_L) as follow:

23. A CDMA receiver as claimed in claim 3, wherein said time measuring section comprises:

a phase measurement section, connected to said high-resolution time reference generating section, said low-resolution time reference generating section, and said notification signal producing section, for measuring, in synchronism with the high-resolution timing signal, the starting difference time interval on the basis of the despreading code timing signal and the low-resolution timing signal, said phase measurement section producing a phase measurement result signal indicative of the starting difference time interval; and

a timing generating section, connected to said high-resolution time reference generating section, said low-resolution time reference generating section, said phase measurement section, said operation control section, and said notification signal producing section, for calculating the high-resolution compensation time interval using the reception operation stop time interval, the starting difference time interval, and the low-resolution use time interval to obtain a calculated result signal indicative of the high-resolution compensation time interval, said timing generating section counting, in response to the calculated result signal, timings for production of the operation control trigger signal and the despreading code timing adjustment signal on the basis of the low-resolution timing signal and the high-resolution timing signal, said timing generating section supplying said operation control section and said notification signal producing section with the operation control trigger signal and the despreading code timing adjustment signal, respectively.

24. A CDMA receiver as claimed in claim 23, wherein said phase measurement section comprises:

a starting difference time interval timer, connected to said high-resolution time reference generating section, said low-resolution time reference generating section, and said notification signal producing section, for timing, in synchronism with the high-resolution timing signal, the starting difference time interval between the despreading code timing signal and the starting time instant of the low-resolution use time interval in response to the low-resolution timing signal and the despreading code timing signal; and

a first register, connected to said start difference time interval timer, for holding the starting difference time interval as a first held time interval, said first register producing the phase measurement result signal indicative of the first held time interval.

25. A CDMA receiver as claimed in claim 24, wherein said timing generating section comprises:

a calculating circuit, connected to said first register, for calculating the high-resolution compensation time interval using the reception operation stop time interval, the first held time interval, and the low-resolution use time interval to produce the calculated result signal indicative of the high-resolution compensation time interval;

a low-resolution use time interval timer, connected to said low-resolution time reference time generating section, for timing, in synchronism with the low-resolution timing signal, a first elapsed time duration from the starting time instant of the low-resolution use time interval, said low-resolution use time interval timer producing a first time-out signal when the first elapsed time duration amounts to the low-resolution use time interval;

a trigger producing circuit, connected to said low-resolution use time interval timer and said calculating section, for producing the operation control trigger signal indicative of the operation stop of said high-resolution time reference generating section in response to the calculated result signal, said trigger producing circuit producing the operation control trigger signal indicative of the operation start of said high-resolution time reference generating section in response to the first time-out signal;

a second register, connected to said calculating circuit, for holding the high-resolution compensation time interval as a second held time interval; and

a high-resolution compensation time interval timer, connected to said low-resolution use time interval timer, said second register, and said high-resolution time reference generating section, for timing, in synchronism with the high-resolution timing signal, a second elapsed time duration from an expiry time instant of the low-resolution use time interval, said high-resolution compensation time interval timer producing a second time-out signal as the despreading code timing adjustment signal when the second elapsed time duration amounts to the second held time interval.

26. A CDMA receiver as claimed in claim 24, wherein said starting difference time interval timer comprises an up-counter for starting, in synchronism with the high-resolution timing signal, an up-count operation in response to an edge of the low-resolution timing signal and for.stopping the up-count operation in response to the despreading code timing signal, said up-counter producing an up-counted value indicative of the starting difference time interval,

said first register holding the up-counted value as a first held value to produce the first held value as the phase measurement result signal.

27. A CDMA receiver as claimed in claim 26, wherein said timing generating section comprises:

a calculation circuit, connected to said first register, for calculating a calculated value indicative of the high-resolution compensation time interval using the reception operation stop time interval, the starting difference time interval, the low-resolution use time interval, and the high-resolution period to produce a calculated result signal indicative of the calculated value;

a first down-counter, connected to said low-resolution time reference generating section and provided with the predetermined positive integer, for carrying out, in synchronism with the low-resolution timing signal, a first down-count operation on a first down-counted value from the predetermined positive integer, said first down-counter producing a first countdown end signal when the first down-counted value is equal to zero;

a trigger producing circuit, connected to said first down-counter and said calculation circuit, for producing the operation control trigger signal indicative of the operation stop of said high-resolution time reference generating section in response to the calculated result signal, said trigger producing circuit producing the operation control trigger signal indicative of the operation start of said high-resolution time reference generating section in response to the first countdown end signal;

a second register, connected to said calculation circuit, for holding the calculated value as a second held value; and

a second down-counter, connected to said first down-counter, said second register, and said high-resolution time reference time generating section, for carrying out, in synchronism with the high-resolution timing signal, a second down-count operation on a second down-counted value from the second held value in response to the first countdown end signal, said second down-counter producing a second countdown end signal as the despreading code timing adjustment signal when the second down-counted value is equal to zero.

28. A CDMA receiver as claimed in claim 27, wherein said predetermined positive integer k is represented by an expression as follows:

29. A CDMA receiver as claimed in claim 28, wherein said low-resolution use time interval (kT_L) is a time interval obtained by multiplying the predetermined positive integer (k) by the low-resolution period (T_L).

30. A CDMA receiver as claimed in claim 29, wherein said starting difference time interval (mT_H) is a time interval obtained by multiplying the up-counted value (m) by the high-resolution period (T_H).

31. A CDMA receiver as claimed in claim 30, wherein said calculated value depicted at n is represented by an expression as follows:

32. A CDMA receiver as claimed in claim 31, wherein said high-resolution compensation time interval (nT_H) is a time interval obtained by multiplying the calculated value (n) by the high-resolution period (T_H).

33. A CDMA receiver as claimed in claim 29, wherein said low-resolution period (T_L) is selected so as to satisfy a relationship among the reception operation stop time interval (Ts), the chip duration depicted at Tc, the predetermined positive integer (k), and the low-resolution period (T_L) as follow:

34. A CDMA receiver as claimed in claim 24, wherein said starting difference time interval timer comprises an up-counter for starting, in synchronism with the high-resolution timing signal, an up-count operation in response to the despreading code timing signal and for stopping the up-count operation in response to an edge of the low-resolution timing signal, said up-counter producing an up-counted value indicative of the starting difference time interval,

said first register holding the up-counted value as a first held value to produce the first held value as the phase measurement result signal.

35. A CDMA receiver as claimed in claim 34, wherein said timing generating section comprises:

a calculation circuit, connected to said first register, for calculating a calculated value indicative of the high-resolution compensation time interval using the reception operation stop time interval, the starting difference time interval, the low-resolution use time interval, and the high-resolution period to produce a calculated result signal indicative the calculated value;

a first down-counter, connected to said low-resolution time reference time generating section and provided with the predetermined positive integer, for carrying out, in synchronism with the low-resolution timing signal, a first down-count operation on a first down-counted value from the predetermined positive integer, said first down-counter producing a first countdown end signal when the first down-counted value is equal to zero;

a trigger producing circuit, connected to said first down-counter and said calculation circuit, for producing the operation control trigger signal indicative of the operation stop of said high-resolution time reference generating section in response to the calculated result signal, said trigger producing circuit producing the operation control trigger signal indicative of the operation start of said high-resolution time reference generating section in response to the first countdown end signal;

a second register, connected to said calculation circuit, for holding the calculated value as a second held value; and

a second down-counter, connected to said first down-counter, said second register, and said high-resolution time reference time generating section, for carrying out, in synchronism with the high-resolution timing signal, a second down-count operation on a second down-counted value from the second held value in response to the first countdown end signal, said second down-counter producing a second countdown end signal as the despreading code timing adjustment signal when the second down-counted value is equal to zero.

36. A CDMA receiver as claimed in claim 35, wherein said predetermined positive integer k is represented by an expression as follows:

37. A CDMA receiver as claimed in claim 36, wherein said low-resolution use time interval (kT_L) is a time interval obtained by multiplying the predetermined positive integer (k) by the low-resolution period (T_L).

38. A CDMA receiver as claimed in claim 37, wherein said starting difference time interval (mT_H) is a time interval obtained by multiplying the up-counted value (m) by the high-resolution period (T_H).

39. A CDMA receiver as claimed in claim 38, wherein said calculated value depicted at n is represented by an expression as follows:

40. A CDMA receiver as claimed in claim 39, wherein said high-resolution compensation time interval (nT_H) is a time interval obtained by multiplying the calculated value (n) by the high-resolution period (T_H).

41. A CDMA receiver as claimed in claim 37, wherein said low-resolution period (T_L) is selected so as to satisfy a relationship among the reception operation stop time interval (Ts), the chip duration (Tc), the predetermined positive integer (k), and the low-resolution period (T_L) as follow:

42. A CDMA receiver as claimed in claim 2, wherein further comprises a frequency correcting section, connected to said low-resolution time reference generating section and said high-resolution time reference generating section, for correcting a frequency of the low-resolution timing signal using the high-resolution timing signal.

43. A CDMA receiver as claimed in claim 42, wherein said frequency correcting section is provided with the reception operation stop time interval, said frequency correcting section controlling the frequency of the low-resolution timing signal so that the starting difference time interval is substantially equal to the high-resolution compensation time interval.

44. A CDMA receiver as claimed in claim 3, wherein further comprises a frequency correcting section, connected to said low-resolution time reference generating section, said high-resolution time reference generating section, and said notification signal producing section, for correcting a frequency and a phase of the low-resolution timing signal using the high-resolution timing signal and the despreading code timing signal.

45. A CDMA receiver as claimed in claim 44, wherein said frequency correcting section is provided with the reception operation stop time interval, said frequency correcting section controlling the frequency and the phase of the low-resolution timing signal so that each of the starting difference time interval and the high-resolution compensation time interval is substantially equal to zero.

46. A receiver for intermittently receiving a received signal, said receiver being alternatively put into a reception operation state and a reception operation stop state for an intermittent reception state, the reception operation stop state continuing for a reception operation stop time interval between a reception stop starting time instant and a reception return time instant, said receiver comprising:

a high-resolution time reference generating section for generating a high-resolution timing signal having a high-resolution period;

a low-resolution time reference generating section for generating a low-resolution timing signal having a low-resolution period which is longer than the high-resolution period; and

a state control section, connected to said high-resolution time reference generating section, for putting, for substantially the operation stop time interval, said receiver into a cold standby state where said high-resolution time reference generating section does not operate while said low-resolution time reference generating section operates, said state control section putting, on or immediately before the reception return time instant, said receiver into a hot standby state where said high-resolution time reference generating section operates;

said receiver further comprising a demodulating section for demodulating the spread spectrum received signal using the despreading code to produce a demodulated signal and a synchronous timing generating section, connected to said demodulating section, for generating a synchronous timing signal for synchronizing said despreading code with the spread spectrum received signal, wherein said state control section comprises;

a time interval measuring section, connected to said high-resolution time reference generating section and said low-resolution time reference generating section, for measuring the reception operation stop time interval by using a combination of a multiple of the low-resolution period and a multiple of the high-resolution period, said time interval measuring section producing an operation control trigger signal and a despreading code timing adjustment signal in response thereto;

an operation control section, connected to said time interval measuring section and said high-resolution time reference generating section, for controlling operation of said high-resolution time reference generating section in response to the operation control trigger signal; and

a notification signal producing section, connected to said time interval measuring section and said synchronous timing generating section, for notifying said synchronous timing generating section of a synchronous timing notification signal in response to the despreading code timing adjustment signal.

47. A method of intermittently receiving a spread spectrum received signal using a despreading code having a chip duration in a code division multiple access (CDMA) receiver which is alternately put into a reception operation state and a reception operation stop state for an intermittent reception state, the reception operation stop state continuing for a reception operation stop time interval between a reception stop starting time instant and a reception return time instant, said CDMA receiver comprising a high-resolution time reference generating section for generating a high-resolution timing signal having a high-resolution period which is shorter than the chip duration and a low-resolution time reference generating section for generating a low-resolution timing signal having a low-resolution period which is longer than the high-resolution period, said method comprising the steps of:

putting, for substantially the reception operation stop time interval, said CDMA receiver into a cold standby state where said high-resolution time reference generating section does not operate while said low-resolution time reference generating section operates; and

putting, on or immediately before the reception return time instant, said CDMA receiver into a hot standby state where said high-resolution time reference generating section operates;

demodulating the spread spectrum received signal using the despreading code to produce a demodulated signal;

generating a synchronous timing signal for synchronizing said despreading code with the spread spectrum received signal;

measuring the reception operation stop time interval by using a combination of a multiple of the low-resolution period and a multiple of the high-resolution period, and producing an operation control trigger signal and a despreading code timing adjustment signal in response thereto;

controlling operation of said high-resolution time reference generating section in response to the operation control trigger signal; and

notifying said synchronous timing generating section of a synchronous timing notification signal in response to the despreading code timing adjustment signal.

48. A method of intermittently receiving a received signal in a receiver which is alternatively put into a reception operation state and a reception operation stop state for an intermittent reception state, the reception operation stop state continuing for a reception operation stop time interval between a reception stop starting time instant and a reception return time instant, said receiver comprising a high-resolution time reference generating section for generating a high-resolution timing signal having a high-resolution period and a low-resolution time reference generating section for generating a low-resolution time reference generating section for generating a low-resolution timing signal having a low-resolution period which is longer than the high-resolution period, said method comprising the steps of:

putting, for substantially the reception operation stop time interval, said receiver into a cold standby state where said high-resolution time reference generating section does not operate while said low-resolution time reference generating section operates; and

putting, on or immediately before the reception return time instant, said receiver into a hot standby state where said high-resolution time reference generating section operates;

demodulating the spread spectrum received signal using the despreading code to produce a demodulated signal;

generating a synchronous timing signal for synchronizing said despreading code with the spread spectrum received signal;

measuring the reception operation stop time interval by using a combination of a multiple of the low-resolution period and a multiple of the high-resolution period, and producing an operation control trigger signal and a despreading code timing adjustment signal in response thereto;

controlling operation of said high-resolution time reference generating section in response to the operation control trigger signal; and

notifying said synchronous timing generating section of a synchronous timing notification signal in response to the despreading code timing adjustment signal.