Frequency channel selection method for radio communication system

• US 6,198,924 B1
• Filed: 08/08/1997
• Issued: 03/06/2001
• Est. Priority Date: 08/14/1996
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ishii, Kenichi, Osawa, Tomoki
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): Kincaid, Lester G.
• Application Number:
  US08/908,979
• Time in Patent Office: 1,306 Days
• Field of Search: 455/11.1, 455/434, 455/62, 455/450, 455/69, 455/522, 455/515, 455/511, 455/440, 455/10, 455/13.4, 455/13.1, 455/516, 370/445, 370/437, 370/450, 370/462
• US Class Current: 455/434
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 72/563 of the wireless resources
• CPC Class Codes: H04W 74/0808 using carrier sensing, e.g. carrier sense multiple access [CSMA]
• CPC Class Codes: H04W 74/0816 with collision avoidance

Abstract

In a channel selection method for a radio communication system constituted by a plurality of radio stations, each radio station transmits a control signal only when required, but need not constantly transmit a control signal.

Claims

1. A communication channel selection method for a radio communication system comprising a plurality of radio stations, wherein each radio station transmits a control packet only when required on the communication channel, said communication channel selection method comprising the steps of:

when establishing a new communication link,

checking a use state of a communication channel to determine if another radio station is using said communication channel; and

selecting said communication channel if said communication channel is not in use, else repeating without delay said checking step for another communication channel; and

when connecting to an existing link,

checking a use state of a communication channel to determine if another radio station is using said communication channel; and

selecting said communication channel if said communication channel is in use, else repeating said checking step for another communication channel;

wherein said steps of checking a use state comprises;

transmitting a control packet on said communication channel;

receiving a response from another one of said radio stations indicating that said communication channel is in use.

2. A method according to claim 1, further comprising the step of:

causing said another one of said radio stations which has received the control packet to transmit no response control packet upon reception of a response control packet from some other radio station.

3. A channel selection method for a radio communication system comprising one or more radio cells, one radio cell comprising a plurality of radio stations connecting to one radio cell sharing one channel, said channel selection method comprising the steps of:

causing each radio station to transmit a control signal only when required, but causing each radio station not to constantly transmit a control signal, when each radio station is to perform packet communication to irregularly and discontinuously perform communication;

causing each radio station to transmit a control signal as a control packet by using a communication channel; and

causing a radio station which is to perform communication to check a state of a communication channel, select a channel determined as a channel that is not being used by any other radio station when a new radio link is to be established, and select a channel determined as a channel that is being used by some other radio station when said radio station is to be connected to an existing radio link.

4. A method according to claim 3, further comprising the step of:

when a radio station which is to perform communication checks states of communication channels, causing said radio station to determine the use states of the channels by receiving packets transmitted from other radio stations by using the respective channels.

5. A method according to claim 3, further comprising the step of:

when a radio station which is to perform communication checks a state of a communication channel, causing said radio station to transmit the control packet and determine the use state of the channel on the basis of a response to the control packet from some other station.

6. A method according to claim 5, further comprising the step of:

causing a radio station which has received the control packet transmitted from said radio station which is to perform communication to transmit a response control packet.

7. A method according to claim 5, further comprising causing only a specific one of radio stations which have received the control packet transmitted from said radio station which is to perform communication to transmit a response control packet.

8. A method according to claim 3, further comprising, when a radio station which is to perform communication checks states of communication channels, causing said radio station to determine the use states of the channels by receiving packets transmitted from other radio stations by using the respective channels.

9. A method according to claim 3, further comprising, when a radio station which is to perform communication checks a state of a communication channel, causing said radio station to transmit the control packet and determine the use state of the channel on the basis of a response to the control packet from some other station.

10. A method according to claim 4, further comprising, when a radio station which is to perform communication checks a state of a communication channel, causing said radio station to transmit the control packet and determine the use state of the channel on the basis of a response to the control packet from some other station.

11. A method according to claim 8, further comprising, when a radio station which is to perform communication checks a state of a communication channel, causing said radio station to transmit the control packet and determine the use state of the channel on the basis of a response to the control packet from some other station.

12. A method according to claim 9, further comprising causing a radio station which has received the control packet transmitted from said radio station which is to perform communication to transmit a response control packet.

13. A method according to claim 10, further comprising causing a radio station which has received the control packet transmitted from said radio station which is to perform communication to transmit a response control packet.

14. A method according to claim 11, further comprising causing a radio station which has received the control packet transmitted from said radio station which is to perform communication to transmit a response control packet.

15. A method according to claim 9, further comprising causing a radio station which has received the control packet transmitted from said radio station which is to perform communication to transmit no response control packet upon reception of a response control packet from some other radio station.

16. A method according to claim 10, further comprising causing a radio station which has received the control packet transmitted from said radio station which is to perform communication to transmit no response control packet upon reception of a response control packet from some other radio station.

17. A method according to claim 11, further comprising causing a radio station which has received the control packet transmitted from said radio station which is to perform communication to transmit no response control packet upon reception of a response control packet from some other radio station.

18. A method according to claim 9, further comprising causing only a specific one of radio stations which have received the control packet transmitted from said radio station which is to perform communication to transmit a response control packet.

19. A method according to claim 10, further comprising causing only a specific one of radio stations which have received the control packet transmitted from said radio station which is to perform communication to transmit a response control packet.

20. A method according to claim 11, further comprising causing only a specific one of radio stations which have received the control packet transmitted from said radio station which is to perform communication to transmit a response control packet.

21. A communication channel selection method for a radio communication system comprising a plurality of radio stations, wherein each radio station transmits a control packet only when required on the communication channel, said communication channel selection method comprising the steps of:

when establishing a new communication link,

checking a use state of a communication channel to determine if another radio station is using said communication channel; and

selecting said communication channel if said communication channel is not in use, else repeating said checking step for another communication channel; and

when connecting to an existing link,

checking a use state of a communication channel to determine if another radio station is using said communication channel; and

selecting said communication channel if said communication channel is in use, else repeating said checking step for another communication channel;

wherein said steps of checking a use state comprises;

transmitting a control packet on said communication channel; and

receiving a response from another one of said radio stations indicating that said communication channel is in use,

wherein said steps of checking the use state of a communication channel comprises the steps of;

checking states of communication channels in a predetermined order common to all radio stations;

checking the states of the communication channels in a reverse order to the predetermined order when an independent network is to be constructed.

22. A communication channel selection method for a radio communication system comprising a plurality of radio stations, wherein each radio station transmits a control packet only when required on the communication channel, said communication channel selection method comprising the steps of:

when establishing a new communication link,

checking a use state of a communication channel to determine if another radio station is using said communication channel; and

selecting said communication channel if said communication channel is not in use, else repeating said checking step for another communication channel; and

when connecting to an existing link,

checking a use state of a communication channel to determine if another radio station is using said communication channel; and

selecting said communication channel if said communication channel is in use, else repeating said checking step for another communication channel;

wherein said steps of checking a use state comprises;

transmitting a control packet on said communication channel; and

receiving a response from another one of said radio stations indicating that said communication channel is in use,

wherein said plurality of radio stations comprise radio base stations and radio mobile stations, said channel selection method further comprising the steps of;

causing each radio base station to transmit a transmission power of a packet as information;

causing a mobile radio station which is to perform communication to transmit a packet with a maximum transmission power; and

determining a transmission power of a packet on said communication channel on the basis of said maximum power and said transmission power transmitted from said base station.

23. A channel selection method for a radio communication system comprising one or more radio cells, one radio cell comprising a plurality of radio stations connecting to one radio cell sharing one channel, said channel selection method comprising the steps of

causing each radio station to transmit a control signal only when required, but causing each radio station not to constantly transmit a control signal, when each radio station is to perform packet communication to irregularly and discontinuously perform communication;

causing each radio station to transmit a control signal as a control packet by using a communication channel;

causing a radio station which is to perform communication to check a state of a communication channel, select a channel determined as a channel that is not being used by any other radio station when a new radio link is to be established, and select a channel determined as a channel that is being used by some other radio station when said radio station is to be connected to an existing radio link;

causing each radio base station to transmit a transmission power of a packet from a self-station as information; and

causing a radio station which is to perform communication to determine, if a packet has been received from a destination radio station, a transmission power of a packet from said self-station in packet transmission on the basis of a reception power of the received packet and a transmission of the power packet, and set, if no packet has been received from said destination radio station, the transmission power of the packet from said self-station to the maximum transmission power.

24. A method for establishing a communication link between a plurality of radio stations using minimum transmission power comprising the steps of:

transmitting a control signal over a communication channel with a first transmission power when a communication link is desired, said control signal containing a data identifying said transmission power;

waiting to receive a response to said control signal from another one of said radio stations;

repeating transmitting said control signal and waiting to receive a response until a response is received, each time increasing said transmission power;

receiving said control signal by another one of said radio stations; and

transmitting a response with a power equal to said data identifying said received transmission power.

25. A method for establishing a communication link between a plurality of radio stations using minimum transmission power comprising the steps of:

transmitting a control signal over a communication with a maximum transmission power when a communication link is desired, said control signal containing a data identifying said maximum transmission power;

receiving said control signal at another one of said radio stations;

determining a power of said received control signal;

calculating a propagation loss by subtracting said power of said received control signal from said maximum power data contained in said control signal; and

establishing a communication link using a transmission power based on said propagation loss.