Receiver for receiving a spectrum dispersion signal

• US 20050147154A1
• Filed: 02/10/2005
• Published: 07/07/2005
• 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 7,269,203 B2
• Time in Patent Office: Days
• US Class Current: 375/130
• 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, in order to reduce a power consumption during a suspension period of intermittent receiving operation, monitors a suspension period t1 by means of a low-power timer 51 so that a VC-TCXO 1, a reference signal group generation unit 2 and a receiving unit 3 are turned off and a modem unit 4 is set to a sleep state. Upon resumption of receiving operation, a high-accuracy timer 44 is supplied with a start (d) to require counting of time t3 and a part of a received signal is stored. A PN code phase of stored data is calculated in a PN code phase calculator 46 during a period t3 to obtain an indication value i for a phase deviation. State vectors for short code and long code and further a reception time t4 are calculated on the basis of the indication value i to be set. When the high-accuracy timer 44 counts t3 and produces 0V(d), demodulation operation by a rake demodulation unit 40, a demultiplexing unit 41 and a descrambler unit 42 is started in accordance with the setting and is continued during the reception time t4.

Claims

1. (canceled)

2. A mobile communication terminal, comprising:

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

a demodulator which demodulates the spread spectrum signal received by said receiver;

a first timer which executes a counting operation when said receiver is in a suspension state, said first timer being driven by a first oscillator;

a second timer which executes a counting operation when the receiver is in a receiving state, said second timer being driven by a second oscillator,

wherein a frequency of said second oscillator is higher than that of said first oscillator and a chip rate of said spread spectrum signal; and

a controller which controls the receiving state and the suspension state of said receiver based on a count by said first timer and said second timer, and controls said demodulator so as to resume demodulation operation so that de-spreading the spread spectrum signal attains synchronization based on an occurrence of an error in said first timer.

3. The mobile communication terminal according to claim 2, further comprising:

a frequency controller which controls a frequency of said second oscillator.

4. The mobile communication terminal according to claim 3, wherein said frequency controller controls the frequency of said second oscillator based on a chip rate of the spread spectrum signal transmitted by a base station.