Wireless communication system

• US 5,896,412 A
• Filed: 07/22/1994
• Issued: 04/20/1999
• Est. Priority Date: 07/22/1994
• Status: Expired due to Fees

• Current Assignee: Crossbow Inc.
• Original Assignee: Crossbow Inc.
• Inventors: Peled, Benjamin, Levanon, Yohanan
• Primary Examiner(s): Pham, Chi H.
• Assistant Examiner(s): WEBSTER, BRYAN E
• Application Number:
  US08/278,885
• Time in Patent Office: 1,733 Days
• Field of Search: 375/200-210, 375/219, 375/222, 375/259, 455/63, 455/509, 455/510, 370/221, 370/222, 370/258
• US Class Current: 375/133
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04B 1/7156 Arrangements for sequence synchronisation
• CPC Class Codes: H04B 7/2621 using frequency division multiple access [FDMA] H04B7/2615 takes precedence

Abstract

A method of wireless communication among a plurality of stations in which each station communicates with all of the other stations over a cycle time divided into a plurality of communication sectors during each of which one of the stations transmits, including the step of changing the frequency of the transmission in accordance with a predetermined protocol, only at the end of a sector in which one of the stations transmits. Preferably, the frequency of transmission is reset to a given frequency in accordance with the protocol when none of the stations transmit over a predetermined period.

Claims

1. A method of wireless communication among a plurality of stations comprising:

causing each of said plurality of stations to directly receive transmission from all other stations on a single common frequency of transmission and in which the frequency of transmission changes in accordance with a predetermined protocol;

determining if one of the stations has transmitted during a given sector;

determining the starting time of a sector based on the time of the last previous transmission prior to the sector; and

changing the frequency of transmission in accordance with the protocol, only for a sector which follows a sector in which one of the stations transmits, wherein each station communicates with all of the other stations over a cycle time divided into a plurality of communication sectors during each of which one of the stations transmit;

wherein the frequency changes at the end of each sector in which a station transmits, in accordance with the protocol.

2. A method of wireless communication among a plurality of stations comprising:

causing each of said plurality of stations to directly receive transmission from all other stations on a single common frequency of transmission and in which the frequency of transmission changes in accordance with a predetermined protocol;

determining if one of the stations has transmitted during a given sector;

determining the starting time of a sector based on the time of the last previous transmission prior to the sector; and

changing the frequency of transmission in accordance with the protocol, only for a sector which follows a sector in which one of the stations transmits, wherein each station communicates with all of the other stations over a cycle time divided into a plurality of communication sectors during each of which one of the stations transmit;

wherein the frequency changes at the end of each sector in which a station transmits, in accordance with the protocol.

3. A method of wireless communications among a plurality of stations in a spread-spectrum, frequency-hopping mode in which a transmission frequency is hopped or changed, comprising:

determining that none of the stations has transmitted during a predetermined period;

determining the starting time of a sector based on the last previous transmission prior to the sector; and

resetting the hopping frequency to a given frequency in accordance with the protocol when none of the stations transmit over a predetermined period,

wherein each station communications with all of the other stations over a cycle time divided into a plurality of communication sectors during each of which one of the stations transmit, and wherein the hopping frequency remains constant during a time in a particular cycle during which one of the station transmits.

6. Apparatus according to claim 3 wherein the predetermined period is one cycle and one sector in length.

4. A method of wireless communication among a plurality of stations, each station communicating with all of the other stations over a cycle time divided into a plurality of communication sectors, comprising:

noting the starting time of each transmission by any station; and

determining the starting time of a sector based on the starting time of the previous transmission by any of the stations prior to the sector,

wherein one station may communicate with all of the other stations during one of the plurality of communication sectors.

5. Communication apparatus for wireless communication among a plurality of stations, each said station comprising:

an antenna;

a transmitter which transmits signals to all of the other stations when it is connected to the antenna;

a receiver which receives signals from all of the other stations when it is connected to the antenna;

a switch which selectively connects one of said transmitter or receiver to the antenna in respective transmission and receiving modes of operation; and

an oscillator which determines the frequency of the transmitter and receiver and which is set to a given frequency in accordance with the protocol when the station has neither received nor transmitted signals during a given period,

wherein each station communicates with all of the other stations in a spread-spectrum, frequency hopping mode in accordance with a predetermined protocol over a cycle time divided into a plurality of communication sectors during each of which one of the stations may transmit,

wherein the transmitter transmits during a sector whose starting time is based on the time of the previous transmission prior to the sector.

7. Apparatus according to claim 5 wherein the frequency changes only at the end of each detector in which the station either transmits or receives a signal or when the station has neither received nor transmitted signal during said given period, in accordance with the protocol.

8. Apparatus according to claim 5 wherein the transmitter transmits during a sector whose starting time is based on the time of the previous transmission prior to the sector.

13. Apparatus according to claim 5 wherein the predetermined length is at least one cycle and one sector in length.

9. Communication apparatus for wireless communication among a plurality of stations, each station comprising:

an antenna;

a transmitter which transmits signals to all of the other stations when it is connected to the antenna;

a receiver which receives signals from all of the other stations when it is connected to the antenna;

a switch which selectively connects one of said transmitter or receiver to the antenna in respective transmission and receiving modes of operation; and

an oscillator which determines the frequency of the transmitter and receiver and which changes said frequency at the end of a sector in response to either transmission or receipt of signals during the sector,

wherein each station communicates with all of the other stations in accordance with a spread-spectrum, frequency hopping mode in accordance with a predetermined protocol over a cycle time divided into a plurality of communication sectors during each of which one of the stations may transmit,

wherein the transmitter transmits during a sector whose starting time is based on the time of the last previous transmission prior to the sector.

10. Apparatus according to claim 9 wherein the oscillator is operative to reserve the frequency to a given frequency in accordance with the protocol when the station neither receives nor transmits during a predetermined period.

11. Apparatus according to claim 10 wherein the predetermined period is at least one cycle and one sector in length.

12. Apparatus according to claim 11 wherein the predetermined period is one cycle and one sector in length.