Receiver for receiving a spectrum dispersion signal

• US 7,471,715 B2
• Filed: 10/12/2007
• Issued: 12/30/2008
• Est. Priority Date: 03/31/1998
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Eguchi, Toshiya, Hasegawa, Osamu, Sudo, Shigeyuki
• Primary Examiner(s): Ha, Dac V
• Application Number:
  US11/907,423
• Publication Number:
  US 20080049815A1
• Time in Patent Office: 445 Days
• Field of Search: 375/130, 375/147, 375/153, 375/354, 370/311, 370/318, 370/335, 370/503, 455/425, 455/574, 455/343.2, 713/320, 713/324, 713/500, 713/502
• 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 mobile communication terminal, comprising:

a receiver which receives a spread spectrum signal transmitted by a base station;

a demodulator which generates a dispreading code for de-spreading the spread spectrum signal received by the receiver and demodulates the spread spectrum signal using the generated dispreading code;

a first oscillator which outputs a first frequency signal, wherein the first frequency signal is a signal having a first frequency;

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

wherein the second frequency signal is a signal having a second frequency, and

wherein an accuracy of a timing implemented based on the second frequency signal is higher than an accuracy of a timing implemented based on the first frequency signal; and

a controller which executes an intermittent receiving operation in which the receiver changes from the suspension state to the receiving state based on a repetition cycle of a slot assigned to the mobile communication terminal,

wherein the controller controls so that the receiver changes from the suspension state to the receiving state and the demodulator starts demodulation operation using the second frequency signal, and controls to maintain the intermittent receiving operation if an output of a signal demodulated by the demodulator is equal to or larger than a predetermined value, and controls to cancel the intermittent receiving operation if the output of the signal is smaller than the predetermined value.

2. The mobile communication terminal according to claim 1, wherein the repetition cycle of the slot is prescribed by 1.28 seconds multiplied by the nth power of 2.