Data transmission within a spread-spectrum communication system

• US 6,400,755 B1
• Filed: 04/23/1999
• Issued: 06/04/2002
• Est. Priority Date: 04/23/1999
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Pazhyannur, Rajesh, Harris, John M.
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): PHU, PHUONG M
• Application Number:
  US09/298,422
• Time in Patent Office: 1,138 Days
• Field of Search: 375/140, 375/146, 375/141, 375/147, 375/150, 370/320, 370/335, 370/342, 370/441
• US Class Current: 375/146
• CPC Class Codes: H04J 13/0044 OVSF [orthogonal variable spreading factor]
• CPC Class Codes: H04J 13/20 having an orthogonal variable spreading factor [OVSF]
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 1/0009 by adapting the channel coding H04L1/1812 takes precedence
• CPC Class Codes: H04L 1/002 Algorithms with memory of the previous states, e.g. Markovian models
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Rate assignment circuitry (102) detects when a data transmission begins and originally assigns an Orthogonal Variable Spreading Factor (OVSF) code corresponding to low data rate. Over time, a base station controller (101) determines when an OVSF code and/or a repetition rate should be changed (i.e., data rate increased or decreased). The OVSF code and/or the repetition rate is changed in order to gradually increase the data rate, up to a maximum allowable data rate. Once data transmission ceases for a period of time the OVSF code and/or the repetition rate is changed in order to gradually decrease the data rate, down to a lowest allowable data rate.

Claims

1. A method for data transmission within a spread-spectrum communication system, the method comprising the steps of:

determining that a data transmission needs to take place;

initiating data transmission within the communication system utilizing a first Orthogonal Variable Spreading Factor (OVSF) code;

determining if data transmission has continued for a preceding period of time to produce a determination;

transmitting data within the communication system utilizing a second OVSF code based on the determination;

wherein the step of transmitting data within the communication system utilizing the second OVSF code based on the determination comprises the steps of transmitting data within the communication system utilizing a second OVSF code of lesser length than the first OVSF code when data transmission has continued for the preceding period of time, and transmitting data within the communication system utilizing a second OVSF code of greater length than the first OVSF code when data transmission has not continued for the preceding period of time.

2. The method of claim 1 further comprising the steps of:

initiating data transmission within the communication system utilizing a first symbol-repetition rate; and

transmitting data within the communication system utilizing a second symbol-repetition rate based on the determination.

3. The method of claim 2 wherein the first symbol-repetition rate corresponds to a low-data-rate symbol repetition rate and the second symbol-repetition rate corresponds to a high-data-rate symbol repetition rate.

4. The method of claim 1 wherein the step of initiating data transmission within the communication system utilizing the first OVSF code comprises the step of initiating data transmission within the communication system utilizing a low-data-rate OVSF code.

5. The method of claim 1 wherein the Step of transmitting data within the communication system utilizing the second OVSF code based on the determination comprises the step of transmitting data within the communication system utilizing the second OVSF code based on the determination, wherein the second OVSF code corresponds to a higher data rate OVSF code.

6. A method for data transmission within a spread-spectrum communication system, the method comprising the steps of:

determining that data transmission needs to take place;

initiating data transmission within the communication system utilizing a first symbol-repetition rate;

determining if data transmission has continued for a preceding period of time to produce a determination;

transmitting data within the communication system utilizing a second symbol-repetition rate based on the determination;

wherein the step of transmitting data within the communication system utilizing the second symbol-repetition rate based on the determination comprises the steps of transmitting data within the communication system utilizing a second symbol-repetition rate of lesser length than the first symbol-repetition rate when data transmission has continued for the preceding period of time, and transmitting data within the communication system utilizing a second symbol-repetition rate of greater length than the first symbol-repetition rate when data transmission has not continued for the preceding period of time.

7. The method of claim 6 further comprising the steps of:

initiating data transmission within the communication system utilizing a first Orthogonal Variable Spreading Factor (OVSF) code; and

transmitting data within the communication system utilizing a second OVSF code based on the determination.

8. The method of claim 7 wherein the first OVSF code corresponds to a low-data-rate code and the second OVSF code corresponds to a high-data-rate code.

9. The method of claim 6 wherein the step of initiating data transmission within the communication system utilizing the first symbol-repetition rate comprises the step of initiating data transmission within the communication system utilizing a symbol-repetition rate corresponding to a low data rate.

10. The method of claim 6 wherein the step of transmitting data within the communication system utilizing the second symbol-repetition rate based on the determination comprises the step of transmitting data within the communication system utilizing the second symbol-repetition rate based on the determination, wherein the second symbol-repetition rate corresponds with a higher data rate.

11. An apparatus for data transmission within a spread-spectrum communication system, the apparatus comprising a symbol repeater outputting symbols having a repetition rate based on a determination that a data transmission has continued for a preceding period of time, wherein the symbol repeater utilizes a symbol-repetition rate of a lesser rate when data transmission has continued for the preceding period of time, otherwise the symbol repeater utilizes a symbol-repetition rate of a greater rate when data transmission has not continued for the preceding period of time.

12. The apparatus of claim 11 further comprising a orthogonal encoder outputting an Orthoganol Variable Spreading Factor (OVSF) code having a length based on the determination.