Method of performing automatic frequency control in mobile station in waiting mode

• US 6,731,911 B1
• Filed: 09/30/1999
• Issued: 05/04/2004
• Est. Priority Date: 10/01/1998
• Status: Expired due to Term

• Current Assignee: Lenovo Innovations Ltd Hong Kong (Lenovo Group Ltd.)
• Original Assignee: NEC Corporation
• Inventors: Arimitsu, Kazuhiro, Hirata, Masaru
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Ward, Ronald J.
• Application Number:
  US09/410,383
• Time in Patent Office: 1,678 Days
• Field of Search: 455/71, 455/75, 455/515, 455/150.1, 455/164.1, 455/68, 455/70, 455/255, 455/257, 375/344, 370/335, 370/342
• US Class Current: 455/71
• CPC Class Codes: H03J 7/04 where the frequency control is accomplished by varying the electrical characteristics of a non-mechanically adjustable element or where the nature of the frequency controlling element is not significant
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception

Abstract

An AFC process is performed even when a mobile station is in a waiting mode in which an incoming call is monitored via a paging channel. Even in the waiting mode, a finger receiver receives a BCCH, and an AFC circuit carries out the AFC process using the BCCH. No reception failure occurs even when a TCXO, i.e., a reference oscillator, suffers frequency fluctuations in the waiting mode.

Claims

1. A method of performing an automatic frequency control process in a mobile station to equalize the frequency of a reference frequency signal for use in demodulating a signal received from a base station, with the frequency of a reference frequency signal in the base station, the method comprising the step of:

receiving a broadcast control channel by one finger receiver in a waiting mode in which a paging channel transmitted from the base station to indicate whether there is an incoming call or not is being received by another finger receiver; and

carrying out the automatic frequency control process using the broadcast control channel in the waiting mode.

3. A method according to claim 1, wherein said step of carrying out said automatic frequency control process comprises the step of controlling a reference oscillator which generates said reference frequency signal.

2. A method of performing an automatic frequency control process in a mobile station to equalize the frequency of a reference frequency signal for use in demodulating a signal received from a base station, with the frequency of a reference frequency signal in the base station, the method comprising the step of:

receiving a broadcast control channel by one finger receiver in a waiting mode in which a paging channel transmitted from the base station to indicate whether there is an incoming call or not is being received by another finger receiver and a frequency error measured using the paging channel is greater than a predetermined value; and

carrying out the automatic frequency control process using the broadcast control channel in the waiting mode.

4. A method according to claim 2, wherein said step of carrying out said automatic frequency control process comprises the step of controlling a reference oscillator which generates said reference frequency signal.