Receiver for receiving a spectrum dispersion signal

• US 20080049815A1
• Filed: 10/12/2007
• Published: 02/28/2008
• Est. Priority Date: 03/31/1998
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Osamu Hasegawa, Shigeyuki Sudo, Toshiya Eguchi
• Inventors: Sudo, Shigeyuki, Hasegawa, Osamu, Eguchi, Toshiya
• Granted Patent: US 7,471,715 B2
• Time in Patent Office: Days
• US Class Current: 375/147
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/70756 Jumping within the code, i.e. masking or slewing H04B1/70758 takes precedence
• CPC Class Codes: H04B 2201/70709 with discontinuous detection
• CPC Class Codes: H04W 52/029 reducing the clock frequency of the controller
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A receiver for the CDMA system which reduces power consumption during a suspension period of intermittent receiving operation by monitoring a suspension period by a low-power timer so that a VC-TCXO, reference signal group generation and receiving units are turned off and a modem unit is set to a sleep state. Upon resumption of receiving operation, a high-accuracy timer is started to count a time period and part of a received signal is stored. A PN code phase of stored data is calculated during the time period to obtain an indication value for phase deviation. State vectors for short and long codes and a further reception time are calculated based on the indication value. When the high-accuracy timer counts the time period and produces 0V(d), demodulation operation by a rake demodulation, demultiplexing, and descrambler units is started and is continued during the reception time.

Claims

1. A receiver for receiving a spread spectrum signal and including means for generating a code for dispreading, comprising:

a first timer;

a second timer; and

intermittent receiving control means for controlling intermittent operation of said receiver,

wherein said intermittent receiving control means, in response to said first timer, controls a suspension period of intermittent receiving operation of said receiver, in response to said second timer, resumes receiving operation of said receiver by calculating a phase of spreading code for a received signal and setting a state value of dispreading code generating means based on the calculated phase of spreading code, and resumes demodulation operation of said receiver so as to demodulate a spread signal, and

wherein a continuation time of the demodulation operation of said receiver is adjusted based on the calculated phase of spreading code.

2. The receiver according to claim 1, further comprising:

a first oscillator which outputs a signal having a first frequency; and

a second oscillator which starts to output a signal having a second frequency when the receiver changes from the suspension period to a receiving period,

wherein the second frequency is higher than the first frequency.

3. The receiver according to claim 2, wherein the second frequency is higher than a chip rate of the spread spectrum signal.

4. The receiver according to claim 3, further comprising:

a frequency controller which adjusts the second frequency.

5. The receiver according to claim 2, wherein the second oscillator is suspended when the receiver is in the suspension period.

6. The receiver according to claim 2, wherein said second oscillator is a voltage controlled type temperature compensation crystal oscillator.

7. A method of receiving a spread spectrum signal intermittently, comprising the steps of:

receiving said spread spectrum signal;

demodulating said spread spectrum signal received by said receiving step;

starting a first timer when said receiving step changes from a suspension state to a receiving state,

wherein an accuracy of a second timer is higher than an accuracy of the first timer and a chip rate of said spread spectrum signal;

controlling said receiving state and said suspension state based on a count by the first timer and the second timer; and

calculating a timing error which occurred due to the first timer,

wherein said controlling step controls a demodulation unit so as to resume demodulation operation so that dispreading said spread spectrum signal attains synchronization based on the timing error after a receiver changes from said suspension state to the receiving state.

8. The method according to claim 7,

wherein a first oscillator outputs a signal having a first frequency,

wherein a second oscillator starts to output a signal having a second frequency when the receiver changes from the suspension state to a receiving state, and

wherein the second frequency is higher than the first frequency.

9. The method according to claim 8, wherein the second frequency is higher than a chip rate of the spread spectrum signal.

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

adjusting the second frequency.

11. The method according to claim 8, wherein the second oscillator is suspended when the receiver is in the suspension state.

12. The method according to claim 8, wherein said second oscillator is a voltage controlled type temperature compensation crystal oscillator.

13. A mobile communication terminal, comprising:

a receiver for receiving a spread spectrum signal and including means for generating a code for dispreading;

a demodulator;

an intermittent receiving control means for controlling intermittent operation of said receiver; and

at least three timers including a first timer, a second timer and a third timer, which are connected to said intermittent receiving control means,

wherein said intermittent receiving control means, in response to said first timer, controls a suspension period of intermittent receiving operation of said receiver, in response to said second timer, resumes receiving operation of said receiver by calculating a phase of spreading code for a received signal and setting a state value of dispreading code generating means based on the calculated phase of spreading code, and resumes demodulation operation of said receiver so as to demodulate a spread signal, and

wherein a continuation time of the demodulation operation of said receiver is adjusted based on the calculated phase of spreading code and provided to the third timer, which controls the continuation time of the demodulation operation.