Frequency-hopping communication system and communication station

• US 6,061,389 A
• Filed: 03/01/1994
• Issued: 05/09/2000
• Est. Priority Date: 03/05/1993
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Adachi, Shuichi, Takiyasu, Yoshihiro, Jusa, Hidehiko, Ishii, Genichi, Ishifuji, Tomoaki, Amada, Eiichi
• Primary Examiner(s): Gregory, Bernarr E.
• Application Number:
  US08/203,373
• Time in Patent Office: 2,261 Days
• Field of Search: 375/1, 375/200-210, 380/34, 379/58, 379/59, 455/33.1, 455/49.1, 455/53.1, 455/54.1, 455/56.1
• US Class Current: 375/133
• CPC Class Codes: H04B 1/713 using frequency hopping
• CPC Class Codes: H04B 1/7136 Arrangements for generation of hop frequencies, e.g. using a bank of frequency sources, using continuous tuning or using a transform
• CPC Class Codes: H04B 1/7156 Arrangements for sequence synchronisation
• CPC Class Codes: H04B 2001/71365 using continuous tuning of a single frequency source
• CPC Class Codes: H04B 2001/71566 Tracking

Abstract

A frequency hopping communication system having a plurality of wireless mobile stations and at least one base station. Each wireless mobile station is operated to communicate according to a communication frame format generated by a base station. The system performing slow frequency hopping by keeping a frequency hopping interval within each frame. The hopping pattern of a frequency is designated at a field located at the tail of each communication frame by the base station.

Claims

1. In a communication system for communicating between a base station and a wireless mobile station through communication frames each having a predetermined format consisting of plural fields, each of said base and wireless mobile stations comprising:

oscillating means for generating a local oscillation signal;

hopping means for hopping said local oscillation signal outputted from said oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame;

a transmission circuit for transmitting a wireless signal in one of said fields of one of said communication frames using said local oscillation signal outputted from said oscillating means as a carrier; and

a receiving circuit for receiving a wireless signal in said one communication frame tuned to said local oscillating signal outputted from said oscillating means;

wherein said one communication frame includes a control field to transfer control information and an information field to transfer data information,

said base station includes means for supplying said transmission circuit with a signal representing control information for designating a station which has a right to transmit a wireless signal in said information field of said one communication frame, based on a timing of said control field of said one communication frame, and

said wireless mobile station includes control means for selecting either operation mode of receiving and transmission at said information field of said one communication frame depending upon said control information extracted from said control field of said one communication frame.

2. In a communication system for communicating between a base station and a wireless mobile station through communication frames having a predetermined format consisting of plural fields,

said base station comprising:

means for generating a first signal representing frame control information to be transmitted at a first field of each of said communication frames and a second signal representing base station identification information to be transmitted at a second field of each of said communication frames,

first oscillating means for generating a local oscillation signal,

hopping means for hopping said local oscillation signal outputted from said first oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a predetermined hopping pattern, and

transmitting means for transmitting said first and second signals generated from said signal generating means by using said local oscillation signal outputted from said first oscillating means as a carrier of a wireless signal;

said wireless mobile station comprising;

second oscillating means for generating a local oscillation signal,

first hopping means for hopping said local oscillation signal outputted from said second oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies a plurality of times a communication frame,

second hopping means for hopping said local oscillation signal outputted from said second oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a hopping pattern specified in accordance with base station identification information,

means for receiving a wireless signal in a communication frame by tuning to said local oscillation signal outputted from said second oscillating means, and

hopping control means for monitoring an output of said receiving means while a frequency of said local oscillation signal outputted from said second oscillating means is being hopped by said first hopping means and for switching said first hopping means to said second hopping means when tuning of said wireless signal to said frequency of said local oscillation signal is detected.

3. A communication system as claimed in claim 2, wherein said wireless mobile station further comprises:

means for outputting a transmission signal of data information with a third field of plural fields of said communication frame; and

transmitting means for transmitting said transmission signal of data information with the local oscillation signal outputted from said second oscillating means and being hopped from one frequency to another frequency among a predetermined sequence of hopping frequencies by said second hopping means as a carrier signal.

4. A communication system as claimed in claim 3, wherein said communication frame includes in sequence a first field for transmitting frame control information, a third field for transmitting data information, and a second field for transmitting base station identification information, and the first hopping means of said wireless mobile station hops the local oscillation signal outputted from said second oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies so as to complete a hopping operation of all frequencies to be selected by said second hopping means during an interval which begins when the head of said communication frame is received and ends when the tail of said third field is received.

5. A communication system as claimed in claim 2, wherein said communication frame includes in sequence a first field for transmitting frame control information, a third field for transmitting frame control information, a third field for transmitting data information, and a second filed for transmitting base station identification information, and the first hopping means of said wireless mobile station hops the local oscillation signal outputted from said second oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies so as to complete a hopping operation of all frequencies to be selected by said second hopping means during a time interval which begins when the head of said communication frame is received and ends when the tail of said third field is received.

6. In a communication system for communicating between a base station and a wireless mobile station through communication frames having a predetermined format consisting of plural fields,

said base station comprising:

signal generating means for generating a first signal representing frame control information to be transmitted at a first field of each of said communication frames and a second signal representing a hopping pattern identifier to be transmitted at a second field of each of said communication frames,

first oscillating means for generating a local oscillation signal and for hopping said local oscillation signal from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a hopping pattern, and

transmission means for transmitting said first and second signals generated from said signal generating means by using said local oscillation signal outputted from said first oscillating means as a carrier of a wireless signal;

said wireless mobile station comprising;

second oscillating means for generating a local oscillation signal,

receiving means for receiving a wireless signal of a communication frame through an antenna by tuning to the local oscillation signal outputted from said second oscillating means,

first hopping means for hopping the local oscillation signal outputted from said second oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies a plurality of times a communication frame,

second hopping means for hopping the local oscillation signal outputted from said second oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a hopping pattern specified in accordance with the hopping pattern identifier received at the second field of said communication frame, and

means for monitoring an output of said receiving means while the local oscillation signal outputted from said second oscillating means is being hopped from one frequency to another frequency among a predetermined sequence of hopping frequencies by said first hopping means and for switching said first hopping means to said second hopping means when a carrier frequency of the wireless signal received at said antenna is detected to be tuned to a frequency of the local oscillation signal outputted from said second oscillating means,

whereby said wireless mobile station receives communication frames while hopping from one frequency to another frequency among a predetermined sequence of hopping frequencies in synchronous to said hopping of frequencies in said base station.

7. A communication system as claimed in claim 6, wherein said wireless mobile station further comprises:

means for outputting a transmission signal of data information on the timing of a third field of plural fields of said communication frame and transmission means for transmitting said transmission signal of data information with the local oscillation signal from said second oscillating means and hopped from one frequency to another frequency among a predetermined sequence of hopping frequencies by said second hopping means as a carrier signal.

8. A communication system as claimed in claim 7, wherein said communication frame includes in sequence a first field for transmitting frame control information, a third field for transmitting data information, and a second field for transmitting a hopping pattern identifier, and the first hopping means of said wireless mobile station hops said local oscillation signal from one frequency to another frequency among a predetermined sequence of hopping frequencies so as to complete a hopping operation of all the frequencies to be selected by said second hopping means during a time interval which begins when the head of said communication frame is received and ends when the tail of said third field is received.

9. A communication system as claimed in claim 6, wherein said communication frame includes in sequence a first field for transmitting frame control information, a third field for transmitting data information, and a second field for transmitting a hopping pattern identifier, and the first hoping means of said wireless mobile station hops said local oscillation signal from one frequency to another frequency among a predetermined sequence of hopping frequencies so as to to complete a hopping operation of all the frequencies to be selected by said second hopping means during a time interval which begins when the head of said communication frame is received to when the tail of said third field is received.

10. A wireless mobile station for communicating with a base according to a frame format of a wireless communication frame consisting of a plurality of fields and for hopping a carrier frequency of said wireless communication frame in synchronous to said base station, said wireless station comprising:

oscillating means for outputting a local oscillation signal;

a transmission circuit for transmitting a transmission signal according to the frame format of said wireless communication frame by using the local oscillation signal as a carrier of a wireless signal through an antenna;

a receiving circuit for receiving a wireless signal in a communication frame through said antenna by tuning to the local oscillation signal outputted from said oscillating means;

control means coupled with said transmission circuit and said receiving circuit for treating said communication frame to have a frame format corresponding to a media access control(MAC) layer frame which includes a data information transfer field at a location after said control field for transferring base station identification information; and

frequency hopping means for hopping the local oscillation signal outputted from said oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a hopping pattern in synchronous to said hopping of frequencies in said base station, said local oscillation signal being hopped from one frequency to another frequency of a predetermined sequence of hopping frequencies at a timing immediately after said control field for transferring said base station identifier in each MAC layer frame.

11. In a communication system for communicating between a base station and a wireless mobile station through communication frames each having a predetermined format consisting of plural fields, each of said base and wireless mobile stations comprising:

an oscillator for generating a local oscillation signal;

a hopping circuit for hopping said local oscillation signal outputted from said oscillator from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame;

a transmission circuit for transmitting a wireless signal in one of said fields of one of said communication frames using said local oscillation signal outputted from said oscillator as a carrier signal; and

a receiving circuit for receiving a wireless signal in said one communication frame tuned to said local oscillating signal outputted from said oscillator;

wherein said one communication frame includes a control field to transfer control information and an information field to transfer data information,

said base station includes a supply circuit for supplying said transmission circuit with a signal representing control information for designating a station which has a right to transmit a wireless signal in said information field of said one communication frame based on a timing of said control field of said communication frame, and

said wireless mobile station includes a control circuit for selecting either operation mode of receiving and transmission at said information field of said one communication frame depending upon said control information extracted from said control field of a received communication frame.

12. In a communication system for communicating between a base station and a wireless mobile station through communication frames having a predetermined format consisting of plural fields,

said base station comprising:

a signal generator for generating a first signal representing frame control information to be transmitted at a first field of each of said communication frames and a second signal representing base station identification information to be transmitted at a second field of each of said communication frames,

a first oscillator for generating a local oscillation signal,

a first hopping circuit for hopping said local oscillation signal outputted from said first oscillator from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a predetermined hopping pattern, and

a transmitter for transmitting said first and second signals generated from said signal generator by using said local oscillation signal outputted from said first oscillator as a carrier of a wireless signal;

said wireless mobile station comprising;

a second oscillator for generating a local oscillation signal,

a first hopping circuit for hopping said local oscillation signal outputted from said second oscillator from one frequency to another frequency among a predetermined sequence of hopping frequencies a plurality of times a communication frame,

a second hopping circuit for hopping said local oscillation signal outputted from said second oscillator from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a hopping pattern specified in accordance with base station identification information,

a receiving circuit for receiving a wireless signal in a communication frame by tuning to said local oscillation signal outputted from said second oscillator, and

a hopping control circuit for monitoring an output of said receiving circuit while said local oscillation signal outputted from said second oscillating means is being hopped from one frequency to another frequency among a predetermined sequence of hopping frequencies by said first hopping circuit and for switching said first hopping circuit to said second hopping circuit when tuning of said wireless signal to said frequency of said local oscillation signal is detected.

13. A communication system as claimed in claim 12, wherein said wireless mobile station further comprises:

an output circuit for outputting a transmission signal of data information with a third field of plural fields of said communication frame; and

a transmitter for transmitting said transmission signal of data information with the local oscillation signal outputted from said second oscillator and being hopped from one frequency to another frequency among a predetermined sequence of hopping frequencies by said second hopping circuit as a carrier signal.

14. A communication system as claimed in claim 13, wherein said communication frame includes in sequence a first field for transmitting frame control information, a third field for transmitting data information, and a second field for transmitting base station identification information, and the first hopping circuit of said wireless mobile station hops the local oscillation signal outputted from said second oscillator from one frequency to another frequency among a predetermined sequence of hopping frequencies so as to complete a hopping operation of all frequencies to be selected by said second hopping circuit during an interval which begins when the head of said communication frame is received and ends when the tail of said third field is received.

15. A communication system as claimed in claim 12, wherein said communication frame includes in sequence a first field for transmitting frame control information, a third field for transmitting frame control information, a third field for transmitting data information, and a second filed for transmitting base station identification information, and the first hopping circuit of said wireless mobile station hops the local oscillation signal outputted from said second oscillator from one frequency to another frequency among a predetermined sequence of hopping frequencies so as to complete a hopping operation of all frequencies to be selected by said second hopping circuit during a time interval which begins when the head of said communication frame is received and ends when the tail of said third field is received.

16. In a communication system for communicating between a base station and a wireless mobile station through communication frames having a predetermined format consisting of plural fields,

said base station comprising:

a signal generator for generating a first signal representing frame control information to be transmitted at a first field of each of said communication frames and a second signal representing a hopping pattern identifier to be transmitted at a second field of each of said communication frames,

a first oscillator for generating a local oscillation signal and for hopping said local oscillation signal from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a hopping pattern, and

a transmitter for transmitting said first and second signals generated from said signal generator by using said local oscillation signal outputted from said first oscillator as a carrier of a wireless signal;

said wireless mobile station comprising;

a second oscillator for generating a local oscillation signal,

a receiver for receiving a wireless signal of a communication frame through an antenna by tuning to the local oscillation signal outputted from said second oscillator,

a first hopping circuit for hopping the local oscillation signal outputted from said second oscillator from one frequency to another frequency among a predetermined sequence of hopping frequencies a plurality of times a communication frame,

a second hopping circuit for hopping the local oscillation signal outputted from said second oscillator from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a hopping pattern specified in accordance with the hopping pattern identifier received at the second field of said communication frame, and

a monitor circuit for monitoring an output of said receiver while the local oscillation signal outputted from said second oscillator is being hopped from one frequency to another frequency among a predetermined sequence of hopping frequencies by said first hopping circuit and for switching said first hopping circuit to said second hopping circuit when a carrier frequency of the wireless signal received at said antenna is detected to be tuned to a frequency of the local oscillating signal outputted from said second oscillator,

whereby said wireless mobile station receives communication frames while hopping from one frequency to another frequency among a predetermined sequence of hopping frequencies in synchronous to said hopping of frequencies in said base station.

17. A communication system as claimed in claim 16, wherein said wireless mobile station further comprises:

an output circuit for outputting a transmission signal of data information on the timing of a third field of plural fields of said communication frame and a transmitter for transmitting said transmission signal of data information with the local oscillation signal from said second oscillator and hopped from one frequency to another frequency among a predetermined sequence of hopping frequencies by said second hopping circuit as a carrier signal.

18. A communication system as claimed in claim 17, wherein said communication frame includes in sequence a first field for transmitting frame control information, a third field for transmitting data information, and a second field for transmitting a hopping pattern identifier, and the first hopping circuit of said wireless mobile station hops said local oscillation signal from one frequency to another frequency among a predetermined sequence of hopping frequencies so as to complete a hopping operation of all the frequencies to be selected by said second hopping circuit during a time interval which begins when the head of said communication frame is received and ends when the tail of said third field is received.

19. A communication system as claimed in claim 16, wherein said communication frame includes in sequence a first field for transmitting frame control information, a third field for transmitting data information, and a second field for transmitting a hopping pattern identifier, and the first hoping circuit of said wireless mobile station hopes said local oscillation signal from one frequency to another frequency among a predetermined sequence of hopping frequencies so as to complete a hopping operation of all the frequencies to be selected by said second hopping circuit during a time interval which begins when the head of said communication frame is received to when the tail of said third field is received.

20. A wireless mobile station for communicating with a base according to a frame format of a wireless communication frame consisting of a plurality of fields and for hopping a carrier frequency of said wireless communication frame in synchronous to said base station, said wireless station comprising:

a oscillator for outputting a local oscillation signal;

a transmission circuit for transmitting a transmission signal according to the frame format of said wireless communication frame by using the local oscillation signal as a carrier of a wireless signal through an antenna;

a receiving circuit for receiving a wireless signal in a communication frame through said antenna by tuning to the local oscillation signal outputted from said oscillator;

a control circuit coupled with said transmission circuit and said receiving circuit for treating said communication frame so as to have such a frame format corresponding to a media access control (MAC) layer frame which includes a data information transfer field at a location after said control field for transferring base station identification information; and

a frequency hopping circuit for hopping the local oscillation signal outputted from said oscillating means from one frequency to another frequency among a predetermined sequence of hopping frequencies once a communication frame according to a hopping pattern in synchronous to said hopping of frequencies in said base station, said local oscillation signal being hopped from one frequency to another frequency among a predetermined sequence of hopping frequencies at a timing immediately after said control field for transferring said base station identifier in each MAC layer frame.