Data transmission within a spread-spectrum communication system

• US 6,233,231 B1
• Filed: 12/03/1998
• Issued: 05/15/2001
• Est. Priority Date: 12/03/1998
• Status: Expired due to Term

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Felix, Kenneth A., Cudak, Mark C., Ghosh, Amitava
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): Bayard, Emmanuel
• Application Number:
  US09/204,702
• Time in Patent Office: 894 Days
• Field of Search: 375/130, 375/135, 375/146, 375/134, 375/133, 375/141, 375/295, 370/206, 370/208, 370/209, 370/320, 370/335, 370/342, 370/431, 370/441, 370/479, 370/524, 370/264, 455/522, 455/456, 455/457, 455/427, 455/450, 455/524
• US Class Current: 370/335
• 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 1/0002 by adapting the transmission rate

Abstract

Remote units (113) having large amounts of data to transmit will be dynamically assigned Orthogonal Variable Spreading Factor (OVSF) codes corresponding to higher data rates and remote units (113) with lower amounts of data to be transmitted will be assigned OVSF codes corresponding to lower data rates. Additionally, in an alternate embodiment of the present invention, once system interference becomes greater than a predetermined threshold, the data rate between the base station (100) and remote units (113) in communication with the base station (100) is reduced. The reduction of the data rate between the base station (100) and remote units (113) occurs by changing the current OVSF codes utilized by both the remote units (113) and the base station (100).

Claims

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

determining data bits to transmit to a remote unit, wherein the data bits include a remote unit identification and a first Walsh (OVSF) code for use by the remote unit;

scrambling the data bits with a second Walsh (OVSF) code to produce scrambled data bits; and

transmitting the scrambled data bits to the remote unit, wherein the remote unit utilizes the first Walsh (OVSF) code to receive high-speed data transmitted to the remote unit from the base station.

2. A method for data transmission from a base station within a spread spectrum communication system, the method comprising the steps of:

determining first data bits to transmit to a first remote unit from the base station, wherein the first data bits include a first remote unit identification and a first Walsh (OVSF) code for use by the remote unit;

determining second data bits to transmit to a second remote unit from the base station, wherein the second data bits include a second remote unit identification and a second Walsh (OVSF) code for use by the second remote unit, wherein the second Walsh (OVSF) code differs from the first Walsh (OVSF) code;

scrambling the first data bits with a third Walsh (OVSF) code to produce first scrambled data bits;

scrambling the second data bits with the third Walsh (OVSF) code to produce second scrambled data bits;

transmitting the first scrambled data bits to the first remote unit, wherein the first remote unit utilizes the first Walsh (OVSF) code to receive high-speed data transmitted to the first remote unit from the base station; and

transmitting the second scrambled data bits to the second remote unit, wherein the second remote unit utilizes the second Walsh (OVSF) code to receive high-speed data transmitted to the second remote unit from the base station.

3. A method for data transmission from a base station within a spread spectrum communication system, the method comprising the steps of:

determining first data bits to transmit to a first remote unit from the base station, wherein the first data bits include a first remote unit identification and a first Walsh (OVSF) code for use by the remote unit;

scrambling the first data bits with a second Walsh (OVSF) code to produce first scrambled data bits;

transmitting the first scrambled data bits to the first remote unit, wherein the first remote unit utilizes the first Walsh (OVSF) code to receive high-speed data transmitted to the remote unit from the base station; and

after the high-speed data has been transmitted to the first remote unit, transmitting second scrambled data bits to a second remote unit, wherein the second remote unit utilizes the first Walsh (OVSF) code to receive high-speed data transmitted to the second remote unit from the base station.

4. An apparatus comprising:

a static Walsh (OVSF) code scrambler having a remote unit identification and a first Walsh (OVSF) code as an input and outputting scrambled data, wherein the scrambled data comprises the remote unit identification and the first Walsh (OVSF) code scrambled by a second, static Walsh (OVSF) code; and

a Cell Specific Scrambler having the scrambled data as an input and outputting the scrambled data further scrambled by a cell-specific scrambling code.

5. An apparatus comprising:

means for determining data bits to transmit to a remote unit, wherein the data bits include a remote unit identification and a first Walsh (OVSF) code for use by the remote unit;

means for scrambling the data bits with a second Walsh (OVSF) code to produce scrambled data bits; and

means for transmitting the scrambled data bits to the remote unit, wherein the remote unit utilizes the first Walsh (OVSF) code to receive second data transmitted to the remote unit from a base station.