Cellular mobile telephone system

• US 5,257,400 A
• Filed: 01/30/1991
• Issued: 10/26/1993
• Est. Priority Date: 01/30/1990
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Yoshida, Ikio
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Charouel, Lisa
• Application Number:
  US07/647,792
• Time in Patent Office: 1,000 Days
• Field of Search: 455/33.1, 455/33.2, 455/33.3, 455/33.4, 455/34.1, 455/34.2, 455/54.1, 455/54.2, 455/56.1, 455/62, 455/161.2, 455/166.2, 379/58, 379/59, 379/60, 379/63
• US Class Current: 455/434
• CPC Class Codes: H04W 48/16 Discovering, processing access restriction or access information
• CPC Class Codes: H04W 76/10 Connection setup

Abstract

In a cellular mobile telephone system serving a plurality of cells, each of the cells being assigned a unique standby channel, the mobile station is assigned several standby channels and a system identifier identifying the system. The standby channels are scanned and one of the scanned channels having a highest signal level is selected. If there is a match between the system identifier of the selected standby channel and the system identifier of the mobile station, the mobile station is ready to originate or receive a call. If there is no originating or incoming call, the identifier of a call setup channel specified by the standby channel is stored into a different location of a memory. Otherwise, the identifiers stored in the memory are scanned, and one of the scanned call setup channels is selected.

Claims

1. A method for selecting channels in a mobile station for a cellular mobile telephone system serving a plurality of cells, each of the cells being assigned a unique standby channel, and said mobile station is assigned a plurality of standby channels and a system identifier identifying said system, the method comprising:

a) scanning said standby channels to detect signal levels and selecting one of the scanned standby channels having a highest signal level;

b) detecting whether there is a match between a system identifier contained in the selected standby channel and the system identifier of said mobile station;

c) if said match is detected, detecting whether there is an originating call from or an incoming call to the mobile station;

d) if there is no originating or incoming call detected by the step (c), storing a channel number of a call setup channel specified by the selected standby channel into a successive location of a memory;

e) repeating the steps (a) to (d); and

f) if there is an originating or incoming call detected by the step (c), selecting one of the call setup channels stored in said memory.

2. A method as claimed in claim 1, wherein the call setup channel selected in step (f) has a highest signal level.

3. A method as claimed in claim 1, wherein the channel number of the call setup channel selected by the step (f) is a most recently stored channel number among the channel numbers stored in said memory.

4. A method as claimed in claim 1, wherein the channel number of the call setup channel selected by the step (f) is a most frequently stored channel number of those stored in said memory.

5. A mobile station for a cellular mobile telephone system serving a plurality of cells, each of the cells being assigned a unique standby channel, and said mobile station is assigned a plurality of standby channels and a system identifier identifying said system, the mobile station comprising:

a tunable radio-frequency transceiver; and

a channel controller coupled to said transceiver for;

a) causing said transceiver to tune to one of the standby channels having a highest signal level;

b) detecting a match between a system identifier contained in the selected standby channel and the system identifier of said mobile station;

c) detecting whether there is an originating call from or an incoming call to the mobile station;

d) storing a channel number of a call setup channel specified by the selected standby channel into a different location of a memory in response to the absence of said originating or incoming call;

e) repeating steps (a)-(d);

f) selecting one of the stored channel numbers in response to the presence of said originating or incoming call; and

g) causing said transceiver to tune to one of the call setup channels having said selected channel number.

6. A mobile station as claimed in claim 5, wherein the tuned call setup channel has a highest signal level among the call setup channels whose channel numbers are stored in said memory.

7. A mobile station as claimed in claim 5, wherein the channel number of the tuned call setup channel is a most recently stored channel number among the channel numbers stored in said memory.

8. A mobile station as claimed in claim 5, wherein the channel number of the tuned call setup channel is a most frequently stored channel number of those stored in said memory.