Mobile station, mobile station communication control method, base station, and communication system

• US 7,974,600 B2
• Filed: 08/17/2004
• Issued: 07/05/2011
• Est. Priority Date: 03/03/2004
• Status: Expired due to Fees

• Current Assignee: Electronic Navigation Research Institute, Mitsubishi Space Software Company Limited (Mitsubishi Electric Corporation)
• Original Assignee: Electronic Navigation Research Institute, Mitsubishi Space Software Company Limited (Mitsubishi Electric Corporation)
• Inventors: Yamagishi, Atsushi, Kanada, Naoki, Shiomi, Kakuichi
• Primary Examiner(s): Corsaro; Nick
• Assistant Examiner(s): DEAN, JR, JOSEPH E
• Application Number:
  US10/591,353
• Publication Number:
  US 20070197208A1
• Time in Patent Office: 2,513 Days
• Field of Search: 455/403, 455/404.1, 455/404.2, 455/567
• US Class Current: 455/404.1
• CPC Class Codes: H04B 2201/70715 with application-specific features
• CPC Class Codes: H04W 4/90 Services for handling of emergency or hazardous situations, e.g. earthquake and tsunami warning systems [ETWS]
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 76/10 Connection setup
• CPC Class Codes: H04W 76/50 for emergency connections

Abstract

It aims at preferentially dealing with emergency communication etc. by a simple and effective method when emergency communication etc. is initiated. In emergency situation, at a mobile station 200, a special call part 206 is switched from a normal mode to an emergency mode, and a mobile station side communication part 206 transmits a radio wave with a transmitted signal of high power (power spectrum density) at the center frequency f₀ of a carrier wave. A base station 100 receives the radio wave with the transmitted signal of high power (power spectrum density) at the center frequency f₀ of the carrier wave, from the mobile station 200 which output communication for emergency situation. The base station 100 outputs suppression signals for suppressing signal intensity to the other mobile stations. Only the mobile station 200 which transmitted the communication for emergency situation establishes a channel to the base station 100.

Claims

1. A mobile station of which communicates with a base station by using a direct sequence system, comprising:

a special call part configured to request initiation of a special call;

a mobile station side transmission part configured to, in response to a request from the special call part, generate a special radio wave signal of high power spectrum density and transmit it to the base station; and

a spread modulation part configured to perform spread modulation of an information signal, wherein

the mobile station side transmission part generates the special radio wave signal to be of high power spectrum density by bypassing the spread modulation part.

3. The mobile station of claim 1 further including a communication control part to restrict a bit rate of the information signal to be low when the mobile station side transmission part generates the special radio wave signal, in order to increase power spectrum density of the special radio wave signal by restricting the bit rate to be low.

4. The mobile station of claim 1, wherein

the mobile station side transmission part performs communication by using the special radio wave signal until a session with the base station is established.

2. A mobile station which communicates with a base station by using a direct sequence system, comprising:

a special call part configured to request initiation of a special call; and

a mobile station side transmission part configured to, in response to a request from the special call part, generate a special radio wave signal of high power spectrum density and transmit it to the base station, wherein

the mobile station side transmission part includes a special code generation part to generate a special code of a direct-current component, and a spread modulation part to perform spread modulation of an information signal by selectively using the special code generated by the special code generation part or a spreading code having a low correlation with a direct-current component depending on whether or not the special radio wave signal is to be generated, and

the mobile station side transmission part generates the special radio wave signal of high power spectrum density by performing spread modulation of the information signal by using the special code of a direct-current component.

11. The mobile station of claim 2, further including a communication control part configured to restrict a bit rate of the information signal to be low when the mobile station side transmission part generates the special radio wave signal, in order to increase power spectrum density of the special radio wave signal by restricting the bit rate to be low.

12. The mobile station of claim 2, wherein

the mobile station side transmission part performs communication by using the special radio wave signal until a session with the base station is established.

5. A mobile station which communicates with a base station by using a direct sequence system, comprising:

a special call part configured to request initiation of a special call; and

a mobile station side transmission part configured to, in response to the request from the special call part, switch from a mode of generating a normal spread modulation signal for the direct sequence system to a mode of generating a special radio wave signal of higher power spectrum density than the normal spread modulation signal, and transmit the special radio wave signal to the base station, wherein

the mobile station side transmission part generates the special radio wave signal of same power as power used in generating the normal spread modulation signal for the direct sequence system, and of a narrower band than a band used in generating the normal spread modulation signal for the direct sequence system.

13. The mobile station of claim 5, wherein

the mobile station side transmission part performs communication by using the special radio wave signal until a session with the base station is established.

6. A communication control method performed by a mobile station side to communicate with a base station by using a direct sequence system, comprising:

requesting initiation of a special call; and

in response to the request for initiation of the special call, switching from a mode of generating a normal spread modulation signal for the direct sequence system to a mode of generating a special radio wave signal of higher power spectrum density than the normal spread modulation signal, and transmitting the special radio wave signal to the base station, wherein

the special radio wave signal is generated of same power as power used in generating the normal spread modulation signal for the direct sequence system, and of a narrower band than a band used in generating the normal spread modulation signal for the direct sequence system.

7. A base station which communicates with a plurality of mobile stations by using a direct sequence system, comprising:

a base station side reception part configured to receive a normal spread modulation signal used in the direct sequence system and a special radio wave signal of high power spectrum density from the plurality of mobile stations, the special radio wave signal being generated of same power as power used in generating the normal spread modulation signal for the direct sequence system, and of a narrower band than a band used in generating the normal spread modulation signal for the direct sequence system;

a detection part configured to detect whether the base station side reception part received the special radio wave signal, and switch modes of extracting information in response to the detection; and

a base station side transmission part configured to transmit an assignment signal for assigning a channel to a mobile station which had transmitted the special radio wave signal detected by the detection part.

8. A communication system where a base station and a plurality of mobile stations communicate using a direct sequence system, comprising:

the plurality of mobile stations, each including

a special call part configured to request initiation of a special call, and

a mobile station side transmission part configured to, in response to a request from the special call part, switch from a mode of generating a normal spread modulation signal for the direct sequence system to a mode of generating a special radio wave signal of higher power spectrum density than the normal spread modulation signal, and transmit the special radio wave signal to the base station, wherein the mobile station side transmission part generates the special radio wave signal of same power as power used in generating the normal spread modulation signal for the direct sequence system, and of a narrower band than a band used in generating the normal spread modulation signal for the direct sequence system; and

the base station including;

a base station side reception part configured to receive the special radio wave signal of high power spectrum density from the plurality of mobile stations,

a detection part configured to detect whether the base station side reception part received the special radio wave signal, and

a base station side transmission part configured to transmit an assignment signal for assigning a channel to a mobile station which had transmitted the special radio wave signal detected by the detection part.

9. A computer-readable medium on which is embodied a communication control program having computer executable instructions for causing a mobile station side to communicate with a base station by using a direct sequence system, comprising instructions for:

requesting initiation of a special call; and

in response to the request for initiation of the special call, switching from a mode of generating a normal spread modulation signal for the direct sequence system to a mode of generating a special radio wave signal of higher power spectrum density than the normal spread modulation signal, and transmitting the special radio wave signal into the base station, wherein

the special radio wave signal is generated of same power as power used in generating the normal spread modulation signal for the direct sequence system, and of a narrower band than a band used in generating the normal spread modulation signal for the direct sequence system.

10. A computer-readable medium on which is embodied a communication control program having computer executable instructions for causing a base station side to communicate with a plurality of mobile stations by using a direct sequence system, comprising instructions for:

receiving a normal spread modulation signal used in the direct sequence system and a special radio wave signal of high power spectrum density from the plurality of mobile stations, the special radio wave signal being generated of same power as power used in generating the normal spread modulation signal for the direct sequence system, and of a narrower band than a band used in generating the normal spread modulation signal for the direct sequence system;

detecting whether the special radio wave signal was received, and switching modes of extracting information in response to the detection; and

transmitting an assignment signal for assigning a channel to a mobile station which had transmitted the special radio wave signal detected.