Communication device with code sequence and frequency selection system

• US 5,317,593 A
• Filed: 03/03/1993
• Issued: 05/31/1994
• Est. Priority Date: 03/03/1993
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Fulghum, Tracy L., Cadd, Jimmy W., Lee, Edward K. B.
• Primary Examiner(s): Swann, Tod R.
• Application Number:
  US08/025,494
• Time in Patent Office: 454 Days
• Field of Search: 375/1, 380/34
• US Class Current: 370/342
• CPC Class Codes: H04J 13/16 Code allocation

Abstract

A code division multiple access (CDMA) communication system (10) for reuse of available spreading codes includes a first communication device (100) and a second communication device (106). The first and second communication devices (100, 106) are capable of identifying spreading codes and operating frequencies that are optimum for their respective radios. The identity of the optimum spreading code and the frequency of the optimum frequency is communicated from one communication device (100) to another (106), hence allowing the two devices to communicate with each other using their respective optimum codes and frequencies. These codes and frequencies may be periodically updated to provide reusability of codes. By dynamically updating codes and frequencies without the use of a central station, the efficiency and reusability of codes in the CDMA system (10) is significantly enhanced.

Claims

1. A Code Division Multiple Access (CDMA) communication system for reuse of available spreading codes, the system having a control spreading code and a control frequency and comprising:

a first communication device for transmitting a signal having the control frequency and spread by the control spreading code, the signal includes a request for an optimum spreading code and an optimum operating frequency;

a second communication device, including;

a receiver for receiving the signal;

first means for identifying a first operating frequency optimum for the second communication device;

second means for identifying a first spreading code optimum for the reception of signals by the second communication device; and

a transmitter for transmitting the identity of the first spreading code and the first optimum operating frequency to the first communication device;

whereby the first and second communication devices communicate using the first operating frequency and the first spreading code.

2. The communication system of claim 1, wherein the first and second communication devices include Direct Sequence Code Division Multiple Access (DSCDMA) communication devices.

3. The communication system of claim 1, wherein the second means for identifying identifies a plurality of spreading codes optimum for the reception of signals by the second communication

4. The communication system of claim 3, wherein the first communication device selects one of the plurality of spreading codes to communicate with the second communication device.

5. The communication system of claim 1, wherein the transmitter includes a controller for requesting a second spreading code that is optimum for the first communication device.

6. The communication system of claim 5, wherein the first communication device includes means for identifying a second spreading code optimum for the first communication device.

7. The communication system of claim 6, wherein the first communication device includes means for identifying a second operating frequency optimum for the first communication device.

8. The communication system of claim 7, wherein the first communication device includes a transmitter for transmitting the second spreading code and the second operating frequency.

9. The communication system of claim 1, wherein the first communication device includes means for periodically checking for optimum codes and communicating them to the second communication device.

10. The communication system of claim 1, wherein the first communication device includes means for periodically checking for optimum operating frequencies and communicating them to the second communication device.

11. In a DS-CDMA communication system having at least a first and a second communication device, a method for providing communication between the first and the second communication devices with optimum reuse of spreading codes and available frequencies, comprising the steps of:

in the first communication device;

transmitting a signal to the second communication device requesting an optimum spreading code and an optimum operating frequency;

in the second communication device;

receiving the signal;

identifying a first operating frequency optimum for the second communication device;

identifying a first spreading code optimum for the second communication device;

transmitting information about the first spreading code and the first operating frequency; and

communicating with the first communication device using the first spreading code and the first operating frequency.

12. The method of claim 11, further including the step of:

in the first communication device, identifying a second spreading code optimum for the first communication device.

13. The method of claim 12, further including the step of:

in the first communication device, transmitting the second spreading code.

14. The method of claim 11 further including the step of:

in the first communication device, identifying a second optimum operating frequency for the first communication device.

15. The method of claim 14, further including the step of:

in the first communication device, transmitting the second optimum operating frequency.

16. The method of claim 11, further including the step of:

in the second communication device, receiving the second spreading code and communicating with the first communication device using the second spreading code.

17. The method of claim 11, further including the step of:

periodically updating the first and second spreading codes.

18. The method of claim 17, further including the step of:

the first and the second communication devices communicating the updated spreading codes to each other as they are updated.

19. The method of claim 11, wherein the step of identifying identifies a plurality of spreading codes optimum for the second communication device.

20. The method of claim 19, further including the step of:

in the first communication device, identifying which of the plurality of spreading codes is optimum to communicate with the second communication device.

21. A multi-channel CDMA communication device having a plurality of codes including a control code, comprising:

a receiver for receiving a signal on a control channel and coded with the control code from a communication unit, the signal including a request for an optimum spreading code and an optimum operating frequency;

first means for identifying the optimum operating frequency;

second means for identifying the optimum spreading code;

a transmitter for transmitting the optimum operating frequency and information about the optimum spreading code; and

the receiver includes means for receiving signals on the optimum operating frequency and decoding signals spread by the optimum spreading code.

22. The receiver of claim 21, further including an adaptable matched filter.

23. The receiver of claim 21, wherein the first means for identifying includes means for periodically searching for optimum spreading codes.

24. The receiver of claim 21, wherein the second means for identifying includes means for periodically searching for optimum operating frequencies.