Wireless computer network communication system and method which determines an available spreading code

• US 6,400,752 B1
• Filed: 10/29/1998
• Issued: 06/04/2002
• Est. Priority Date: 09/29/1994
• Status: Expired due to Fees

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Takahashi, Satoshi, Suzuki, Masamitsu, Kokaji, Harumi, Nakagawa, Yoshikatsu
• Primary Examiner(s): VO, DON NGUYEN
• Application Number:
  US09/181,925
• Time in Patent Office: 1,314 Days
• Field of Search: 375/130, 375/132, 375/133, 455/63, 455/434, 455/515, 370/335, 370/344, 370/445
• US Class Current: 375/133
• CPC Class Codes: H04B 1/7103 the interference being multiple access interference
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 72/0466 the resource being a scrambling code

Abstract

A wireless network communication system and method in which the wireless channel can be determined by selecting a vacant pseudonoise (PN) or spreading code. When communication is started, in order to judge whether a PN code is being employed by another communication group, the degree of correlation between the received signal converted to an intermediate frequency or a base-band frequency by a transceiver and a reference pseudonoise code signal is detected using a correlation circuit within a correlation detector. There is a channel controller which controls the PN code used by the communication terminal which receives an output of the correlation detector which correlates a received channel signal with a reference PN code generated by the PN code generator. If the correlation output signal is not smaller than a threshold value, it is determined that the PN code is to be employed. Furthermore, at the time of transmission, the pseudonoise code generator is controlled so as to supply the selected PN code to a transceiver. The transceiver combines the data to be transmitted with the PN code to be used in order to determine the final signal which is to be transmitted by the terminal.

Claims

1. A wireless network communication method using at least two groups of wireless terminals, comprising the steps of:

communicating using a sub-band of a frequency band by a first group of the wireless terminals;

determining, by a terminal of a second group of terminals, information defining how sub-bands of the frequency band are to be used by the second group of wireless terminals;

notifying, by said terminal, other terminals of the second group of said information;

communicating, by the second group of terminals, on a sub-band of said frequency band in accordance with said information when there is an absence of a signal from the first group of wireless terminals on the sub-band being used by the second group of terminals.

2. A method according to claim 1, further comprising, performed before said step of determining information, the step of:

determining a vacancy and use of sub-bands of the frequency band, by the terminal of the second group of the wireless terminals,

wherein the step of determining information is performed using a result of the analyzing step.

3. A method according to claim 2, wherein said determining step of determining the vacancy and use comprises:

determining the vacancy and use of sub-bands by analyzing communications on the sub-bands of the frequency band.

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

acknowledging the selected channel by the other terminals of the second group.

5. A method of communicating by a first group of terminals, comprising the steps of:

transmitting, by the host terminal of the first group, an inquiry code requesting information indicating at least one spreading code used by another group of terminals;

receiving information indicating the at least one spreading codes being used;

selecting a spreading code to be used by the first group using the information which was received; and

communicating by the first group using spread spectrum communication in accordance with the spreading code which has been selected.

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

sensing, by a host terminal of the first group, spreading codes which are vacant and available for use by the first group.

7. A method according to claim 5, wherein:

said step of transmitting an inquiry includes transmitting an inquiry using a spreading code having a maximum correlation magnitude.

8. A method according to claim 5, wherein:

said step of selecting a spreading code comprises selecting a pseudonoise (PN) code; and

said step of communicating comprises communicating by the first group using code-division multiple access communication using the spreading code which has been selected.

9. A wireless network communication system using at least two groups of wireless terminals, comprising:

means for communicating, using a sub-band of a frequency band, by a first group of the wireless terminals;

means for determining, by a terminal of a second group of wireless terminals, information defining how sub-bands of the frequency band are to be used by the second group of wireless terminals;

means for notifying, by said terminal, other terminals of the second group of said information; and

means for communicating, by the second group of terminals, on a sub-band of said frequency band in accordance with said information when there is an absence of a signal from the first group of wireless terminals on the sub-band being used by the second group of terminals.

10. A system according to claim 9, further comprising:

means for determining a vacancy and use of sub-bands of the frequency band, by a terminal of a second group of the wireless terminals,

wherein the means for determining information operates using a result of the analyzing step.

11. A system according to claim 10, wherein said means for determining the vacancy and use comprises:

means for determining the vacancy and use of sub-bands by analyzing communications on the sub-bands of the frequency band.

12. A system according to claim 9, further comprising the step of:

acknowledging the selected channel by the other terminals of the second group.

13. A system for communicating by a first group of terminals, comprising:

means for transmitting, by the host terminal of the first group, an inquiry code requesting information indicating at least one spreading code used by another group of terminals;

means for receiving information indicating the at least one spreading codes being used;

means for selecting a spreading code to be used by the first group using the information which was received; and

means for communicating by the first group using spread spectrum communication in accordance with the spreading code which has been selected.

14. A system according to claim 13, further comprising:

means for sensing, by a host terminal of the first group, spreading codes which are vacant and available for use by the first group.

15. A system according to claim 13, wherein:

said means for transmitting an inquiry includes means for transmitting an inquiry using a spreading code having a maximum correlation magnitude.

16. A system according to claim 13, wherein:

said means for selecting a spreading code comprises means for selecting a pseudonoise (PN) code; and

said means for communicating comprises means for communicating by the first group using code-division multiple access communication using the spreading code which has been selected.