Spread spectrum method

• US 5,235,615 A
• Filed: 07/21/1992
• Issued: 08/10/1993
• Est. Priority Date: 05/22/1991
• Status: Expired due to Fees

• Current Assignee: Taggert Hodings LLC (Intellectual Ventures LLC)
• Original Assignee: Cylink Corp. (Thales SA)
• Inventors: Omura, Jimmy K.
• Primary Examiner(s): Swann, Tod R.
• Application Number:
  US07/915,741
• Time in Patent Office: 385 Days
• Field of Search: 375/1, 380/34, 379/59, 379/61, 379/63, 455/33.1, 455/51, 455/57, 370/18, 370/19, 370/20, 370/21, 370/22
• US Class Current: 370/342
• CPC Class Codes: H04B 7/2668 Arrangements for Wireless Code-Division Multiple Access [CDMA] System Synchronisation, for code acquisition H04B1/7075, for code tracking H04B1/7085
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04W 36/0085 Hand-off measurements
• CPC Class Codes: H04W 56/00 Synchronisation arrangements

Abstract

A method for establishing and communicating synchronous, code division multiple access communications between a base station and a plurality of remote units. A plurality of remote-communications signals which have spread-spectrum modulation are transmitted from the plurality of remote units and arrive simultaneously at the base station. The method includes transmitting repetitively from the base station a access signal having spread-spectrum modulation and receiving the access signal at an accessing-remote unit. The accessing-remote unit transmits an echo signal which has spread-spectrum modulation. The echo signal is received at the base station and a time delay is measured between the access signal and the received echo signal. A protocol signal which has spread-spectrum modulation is transmitted to the accessing-remote unit, with the protocol signal communicating a chip codeword and the time delay measured at the base station. The accessing-remote unit adjusts a delay time such that the communications signal transmitted from the accessing-remote unit arrives simultaneously at the base station with communications signals transmitted from the plurality of remote units. The base station communicates to the plurality of remote units, with a plurality of base-communications signals. Each chip codeword of each base-communications signal is orthogonal to chip codewords of the plurality of base-communications signals.

The plurality of remote-communications signals arrive simultaneously at the base station with each chip codeword of each remote-communications signal orthogonal to chip codewords of the plurality of remote-communications signals.

Claims

1. A method for establishing and communicating synchronous, code division multiple access communications on a same frequency between a base station and a plurality of remote units, with a plurality of remote-communications signals having spread-spectrum modulation from the plurality of remote units arriving simultaneously at said base station, the method for each accessing-remote unit comprising the steps of:

transmitting repetitively from said base station an access signal having spread-spectrum modulation;

receiving the access signal at said access-remote unit;

transmitting responsive to the access signal, from said accessing-remote unit, an echo signal having spread-spectrum modulation;

receiving the echo signal at said base station;

measuring a time delay at said base station between the access signal and the received echo signal;

transmitting a protocol signal having spread-spectrum modulation from said base station to said accessing-remote unit, with the protocol signal communicating a chip codeword and the time delay measured at said base station;

receiving the protocol signal at said accessing-remote unit;

adjusting at said accessing-remote unit a delay time such that the communications signal transmitted from said accessing-remote unit arrives simultaneously at said base station with communications signals transmitted from the plurality of remote units;

communicating from said base station to said plurality of remote units, with a plurality of base-communications signals having spread-spectrum modulation transmitted simultaneously from said base station, with each chip codeword of each base-communications signal orthogonal to chip codewords of the plurality of base-communications signals; and

communicating from said plurality of remote units to said base station with the plurality of remote-communications signals having spread-spectrum modulation transmitted from said plurality of remote units, respectively, the plurality of remote-communications signals arriving simultaneously at said base station with each chip codeword of each remote-communications signal orthogonal to chip codewords of the plurality of remote-communications signals.

2. A method for communicating synchronous, code division multiple access communications between a base station and a plurality of remote units, with a plurality of remote-communication signals having spread-spectrum modulation from the plurality of remote units arriving simultaneously at said base station, comprising the steps of:

transmitting repetitively from said base station an access signal having spread-spectrum modulation;

receiving the access signal at said access-remote unit;

transmitting, responsive to the access signal, from said accessing-remote unit, an echo signal having spread-spectrum modulation;

receiving the echo signal at said base station;

measuring a time delay at said base station between the access signal and the received echo signal;

transmitting a protocol signal having spread-spectrum modulation from said base station to said accessing-remote unit, with the protocol signal communicating a chip codeword and the time delay measured at said base station;

receiving the protocol signal at said accessing-remote unit;

adjusting at said accessing-remote unit a delay time such that the communications signal transmitted from said accessing-remote unit arrives simultaneously at said base station with communications signals transmitted from the plurality of remote units; and

communicating from said base station to said plurality of remote units, with a plurality of base-communications signals having spread-spectrum modulation transmitted simultaneously from said base station.

3. A method for establishing synchronous, code division multiple access communications between a base station and a plurality of remote units, with a plurality of remote-communications signals having spread-spectrum modulation from the plurality of remote units arriving simultaneously at said base station, the method for each accessing-remote unit comprising the steps of:

transmitting repetitively from said base station an access signal having spread-spectrum modulation;

receiving the access signal at said accessing-remote unit;

transmitting responsive to the access signal, from said accessing-remote unit, an echo signal having spread-spectrum modulation;

receiving the echo signal at said base station;

measuring a time delay at said base station between the access signal and the received echo signal;

transmitting a protocol signal having spread-spectrum modulation from said base station to said accessing-remote unit, with the protocol signal communicating the time delay measured at said base station;

receiving the protocol signal at said accessing-remote unit; and

adjusting at said accessing-remote unit a delay time such that the communications signal transmitted from said accessing-remote unit arrives simultaneously at said base station with communications signals transmitted from the plurality of remote units.

4. A method for establishing and communicating synchronous, code division multiple access communications on a same frequency between a base station and a plurality of remote units, with a plurality of remote-communication signals having spread-spectrum modulation from the plurality of remote units arriving simultaneously at said base station, the method for each accessing-remote unit comprising the steps of:

transmitting repetitively from said base station an access signal having spread-spectrum modulation;

receiving the access signal at said access-remote unit;

transmitting, responsive to the access signal, from said accessing-remote unit, an echo signal having spread-spectrum modulation;

receiving the echo signal at said base station;

measuring a time delay at said base station between the access signal and the received echo signal;

transmitting a protocol signal having spread-spectrum modulation from said base station to said accessing-remote unit, with the protocol signal communicating a chip codeword and the time delay measured at said base station;

receiving the protocol signal at said accessing-remote unit;

adjusting at said accessing-remote unit a delay time such that the communications signal transmitted from said accessing-remote unit arrives simultaneously at said base station with communications signals transmitted from the plurality of remote units;

communicating from said base station to said plurality of remote units, with a plurality of base-communication signals having spread-spectrum modulation transmitted simultaneously from said base station; and

communicating from said plurality of remote units to said base station with the plurality of remote-communication signals having spread-spectrum modulation transmitted from said plurality of remote units, respectively, the plurality of remote-communication signals arriving simultaneously at said base station.

5. A method for communicating synchronous, code division multiple access communications on a same frequency between a base station and a plurality of remote units, the method comprising the steps of:

transmitting repetitively from said base station an access signal having spread-spectrum modulation;

receiving the access signal at said access-remote unit;

transmitting, responsive to the access signal, from said accessing-remote unit, an echo signal having spread-spectrum modulation;

receiving the echo signal at said base station;

measuring a time delay at said base station between the access signal and the received echo signal;

transmitting a protocol signal having spread-spectrum modulation from said base station to said accessing-remote unit, with the protocol signal communicating a chip codeword and the time delay measured at said base station;

receiving the protocol signal at said accessing-remote unit;

adjusting at said accessing-remote unit a delay time such that the communications signal transmitted from said accessing-remote unit arrives simultaneously at said base station with communications signals transmitted from the plurality of remote units; and

communicating from said plurality of remote units to said base station with the plurality of remote-communication signals having spread-spectrum modulation transmitted from said plurality of remote units, respectively, the plurality of remote-communication signals arriving simultaneously at said base station.

6. A method for establishing and communicating synchronous, code division multiple access communications on a same frequency between a base station and a plurality of remote units, with a plurality of remote-communication signals having spread-spectrum modulation from the plurality of remote units arriving simultaneously at said base station, the method for each accessing-remote unit comprising the steps of:

transmitting an access signal;

receiving the access signal;

transmitting an echo signal;

receiving the echo signal;

measuring a time delay between the access signal and the received echo signal;

transmitting a protocol signal;

receiving the protocol signal; and

adjusting a delay time.

7. The method as set forth in claim 6, further comprising the step of:

communicating from said plurality of remote units to said base station with the plurality of remote-communication signals having spread-spectrum modulation transmitted from said plurality of remote units, respectively, the plurality of remote-communication signals arriving simultaneously at said base station.

8. The method as set forth in claim 6, further comprising the step of:

communicating from said base station to said plurality of remote units.

9. The method as set forth in claim 7, further comprising the step of:

communicating from said base station to said plurality of remote units.

10. A system for communicating synchronous, code division multiple access communications on a same frequency between a base station and a plurality of remote units, with a plurality of remote-communication signals having spread-spectrum modulation from the plurality of remote units arriving simultaneously at said base station, the system comprising:

a base station for transmitting simultaneously a plurality of base-communication signals having spread-spectrum modulation; and

a plurality of remote units for transmitting simultaneously a plurality of remote-communication signals having spread-spectrum modulation;

wherein each remote unit receives an access signal, each remote unit transmits an echo signal having spread-spectrum modulation, each remote unit receives a protocol signal, each remote unit adjusts a delay time such that the remote-communication signals transmitted from each remote unit arrives simultaneously at said base station with the remote-communication signals transmitted from the plurality of remote units.

11. A system for establishing and communicating synchronous, code division multiple access communications on a same frequency between a base station and a plurality of remote units, with a plurality of remote-communication signals having spread-spectrum modulation from the plurality of remote units arriving simultaneously at said base station, the system comprising:

a base station, said base station transmitting repetitively an access signal having spread-spectrum modulation, said base station receiving an echo signal having spread-spectrum modulation, said base station measuring a time delay between the access signal and the received echo signal, said base station transmitting a protocol signal having spread-spectrum modulation; and

a plurality of remote units, each remote unit receiving the access signal, each remote unit transmitting the echo signal having spread-spectrum modulation, each remote unit receiving the protocol signal, each remote unit adjusting a delay time such that the remote-communication signal transmitted from each remote unit arrives simultaneously at said base station with the remote-communication signals transmitted from the plurality of remote units.

12. A system for communicating synchronous, code division multiple access communications on a same frequency between a base station and a plurality of remote units, comprising:

a base station, said base station transmitting repetitively an access signal having spread-spectrum modulation, said base station receiving an echo signal having spread-spectrum modulation, said base station measuring a time delay between the access signal and the received echo signal, said base station transmitting a protocol signal having spread-spectrum modulation; and

a plurality of remote-units;

wherein said plurality of remote units communicate to said base station with a plurality of remote-communication signals having spread-spectrum modulation transmitted from said plurality of remote units, respectively, the plurality of remote-communication signals arriving simultaneously at said base station.

13. The system as set forth in claim 12, wherein said base station communicates to said plurality of remote units, with a plurality of base-communication signals having spread-spectrum modulation transmitted simultaneously from said base station.