System and method for generating signal waveforms in a CDMA cellular telephone system

• US 20060088134A1
• Filed: 12/07/2005
• Published: 04/27/2006
• Est. Priority Date: 06/25/1990
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Wheatley, Charles E. III, Gilhousen, Klein S., Padovani, Roberto, Jacobs, Irwin M., Viterbi, Andrew J., Weaver, Lindsay A. Jr.
• Granted Patent: US 7,839,960 B2
• Time in Patent Office: Days
• US Class Current: 375/345
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/70757 with increased resolution, i.e. higher than half a chip H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 7/2618 using hybrid code-time division multiple access [CDMA-TDMA]
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04B 7/2637 for logical channel control
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/0048 Walsh
• CPC Class Codes: H04J 13/12 Generation of orthogonal codes
• CPC Class Codes: H04J 3/02 Details electronic switching or gating H03K17/00
• CPC Class Codes: H04J 3/1688 the demands of the users being taken into account after redundancy removal, e.g. by predictive coding, by variable sampling reducing bandwidth of signals in general H04B1/66; in PCM-systems H04B14/046; removal of redundancy in telegraph communication H03M7/30
• CPC Class Codes: H04J 3/22 in which the sources have different rates or codes simultaneous speech and digital data or video transmission H04M11/06; see provisional also H04J3/16
• CPC Class Codes: H04L 1/0002 by adapting the transmission rate
• CPC Class Codes: H04L 1/0071 Use of interleaving interleaving per se H03M13/27
• CPC Class Codes: H04L 1/0072 Error control for data other than payload data, e.g. control data
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 1/08 by repeating transmission, e.g. Verdan system H04L1/1858 and H04L1/189 take precedence
• CPC Class Codes: H04L 23/02 adapted for orthogonal signalling
• CPC Class Codes: H04L 5/02 : Channels characterised by the type of signal
• CPC Class Codes: H04L 5/12 : the signals being represented by different phase modulations of a single carrier
• CPC Class Codes: H04W 52/08 : Closed loop power control
• CPC Class Codes: H04W 52/10 : Open loop power control
• CPC Class Codes: H04W 52/26 : using transmission rate or quality of service QoS [Quality of Service]

Abstract

A system and method for communicating information signals using spread spectrum communication techniques. PN sequences are constructed that provide orthogonality between the users so that mutual interference will be reduced, allowing higher capacity and better link performance. With orthogonal PN codes, the cross-correlation is zero over a predetermined time interval, resulting in no interference between the orthogonal codes, provided only that the code time frames are time aligned with each other. In an exemplary embodiment, signals are communicated between a cell-site and mobile units using direct sequence spread spectrum communication signals. In the exemplary embodiment, transmit power of mobile unit signals is controlled based on signal power received by the mobile unit and power adjustment commands sent to the mobile unit.

Claims

1. A mobile unit, comprising:

means for receiving a signal including power adjustment commands;

first means for adjusting a power level of a transmit signal in response to the power adjustment commands; and

second means for adjusting the power level of the transmit signal in response to a power level of the signal.

2. The mobile unit of claim 1, wherein the means for receiving comprises means for removing the power adjustment commands from the signal, the power adjustment commands having been punctured into the signal.

3. The mobile unit of claim 1, wherein the first means comprises a digital control signal.

4. The mobile unit of claim 1, wherein the second means comprises an analog control signal.

5. A method of controlling a power level of a transmit signal, comprising:

receiving a signal including power adjustment commands;

controlling a power level of a transmit signal in response to the power adjustment commands; and

adjusting the power level of the transmit signal in response to a power level of the signal.

6. The method of claim 5, wherein the receiving comprises removing the power adjustment commands from the signal, the power adjustment commands having been punctured into the signal.

7. The method of claim 5, wherein the controlling comprises controlling with a digital control signal.

8. The method of claim 5, wherein the adjusting comprises adjusting with an analog control signal.

9. A mobile unit, comprising:

a receiver configured to receive and demodulate a signal having a received power level and including power adjustment commands;

a control processor coupled to the receiver and configured to receive the power adjustment commands from the receiver and generate therefrom a first control signal;

an automatic gain control (AGC) circuit coupled to the receiver and configured to generate a second control signal based on the received power level of the signal; and

power control circuitry coupled to the control processor and the AGC circuit and configured to receive the first control signal from the control processor and adjust a power level of a transmit signal in accordance with the first control signal, and to receive the second control signal from the AGC circuit and adjust the power level of the transmit signal based on the second control signal.

10. The mobile unit of claim 9, wherein the receiver is further configured to remove the power adjustment commands from the signal, the power adjustment commands having been punctured into the signal.

11. The mobile unit of claim 9, wherein the first control signal is a digital control signal.

12. The mobile unit of claim 9, wherein the second control signal is an analog control signal.