Automatic power control system for a code division multiple access (CDMA) communications system

• US 6,674,788 B2
• Filed: 02/27/2002
• Issued: 01/06/2004
• Est. Priority Date: 06/30/1995
• Status: Expired due to Term

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Ozluturk, Fatih, Kowalski, John, Lomp, Gary
• Primary Examiner(s): Ghebretinsae, Temesghen
• Application Number:
  US10/083,846
• Publication Number:
  US 20020118722A1
• Time in Patent Office: 678 Days
• Field of Search: 375/130, 375/148, 375/146, 455/69, 455/522, 370/342, 370/335
• US Class Current: 375/130
• CPC Class Codes: G06F 13/374 using a self-select method with individual priority code comparator
• CPC Class Codes: H03H 17/0226 comprising look-up tables
• CPC Class Codes: H03H 17/06 Non-recursive filters
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/70753 Partial phase search
• CPC Class Codes: H04B 1/70754 Setting of search window, i.e. range of code offsets to be searched H04B1/70758 takes precedence
• CPC Class Codes: H04B 1/70755 Setting of lock conditions, e.g. threshold
• CPC Class Codes: H04B 1/70758 Multimode search, i.e. using multiple search strategies
• CPC Class Codes: H04B 1/7077 Multi-step acquisition, e.g. multi-dwell, coarse-fine or validation
• CPC Class Codes: H04B 1/708 Parallel implementation
• CPC Class Codes: H04B 1/7085 using a code tracking loop, e.g. a delay-locked loop
• CPC Class Codes: H04B 1/709 Correlator structure
• CPC Class Codes: H04B 1/7093 Matched filter type
• CPC Class Codes: H04B 1/711 the interference being multi-path interference
• CPC Class Codes: H04B 1/7115 Constructive combining of multi-path signals, i.e. RAKE receivers
• CPC Class Codes: H04B 1/712 Weighting of fingers for combining, e.g. amplitude control or phase rotation using an inner loop
• CPC Class Codes: H04B 2201/70701 featuring pilot assisted reception
• CPC Class Codes: H04B 2201/70702 Intercell-related aspects
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 2201/70707 : Efficiency-related aspects
• CPC Class Codes: H04B 2201/7071 : with dynamic control of receiver resources
• 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: H04B 7/264 : for data rate control
• CPC Class Codes: H04J 13/00 : Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04J 13/004 : Orthogonal
• CPC Class Codes: H04J 13/0048 : Walsh
• CPC Class Codes: H04J 13/0077 : Multicode, e.g. multiple codes assigned to one user
• CPC Class Codes: H04J 13/10 : Code generation
• CPC Class Codes: H04J 13/107 : by concatenation
• CPC Class Codes: H04J 13/12 : Generation of orthogonal codes
• CPC Class Codes: H04J 13/16 : Code allocation
• CPC Class Codes: H04J 2013/0037 : Multilevel codes
• CPC Class Codes: H04L 1/0001 : Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/004 : by using forward error control H04L1/0618 takes precedence; coding, decoding or code conversion, for error detection or correction H03M13/00
• CPC Class Codes: H04L 1/0042 : Encoding specially adapted to other signal generation operation, e.g. in order to reduce transmit distortions, jitter, or to improve signal shape H04L1/0067 takes precedence
• CPC Class Codes: H04L 1/0047 : Decoding adapted to other signal detection operation in conjunction with sequence estimation or equalization H04L25/03286
• CPC Class Codes: H04L 1/0054 : Maximum-likelihood or sequential decoding, e.g. Viterbi, Fano, ZJ algorithms
• CPC Class Codes: H04L 1/0059 : Convolutional codes
• CPC Class Codes: H04L 2027/003 : at baseband only
• CPC Class Codes: H04L 2027/0053 : Closed loops
• CPC Class Codes: H04L 25/0212 : of impulse response
• CPC Class Codes: H04L 27/206 : using a pair of orthogonal carriers, e.g. quadrature carriers
• CPC Class Codes: H04L 27/2332 : using a non-coherent carrier
• CPC Class Codes: H04L 5/1446 : of transmission speed
• CPC Class Codes: H04N 1/00912 : Arrangements for controlling a still picture apparatus or components thereof not otherwise provided for
• CPC Class Codes: H04N 1/3333 : during transmission, input or output of the picture signal; within a single document or page
• CPC Class Codes: H04N 2201/3335 : Speed or rate
• CPC Class Codes: H04W 52/04 : TPC
• CPC Class Codes: H04W 52/08 : Closed loop power control
• CPC Class Codes: H04W 52/143 : Downlink power control
• CPC Class Codes: H04W 52/146 : Uplink power control
• CPC Class Codes: H04W 52/24 : using SIR [Signal to Interference Ratio] or other wireless path parameters
• CPC Class Codes: H04W 52/241 : taking into account channel quality metrics, e.g. SIR, SNR, CIR, Eb/lo
• CPC Class Codes: H04W 52/245 : taking into account received signal strength
• CPC Class Codes: H04W 52/247 : where the output power of a terminal is based on a path parameter sent by another terminal
• CPC Class Codes: H04W 52/26 : using transmission rate or quality of service QoS [Quality of Service]
• CPC Class Codes: H04W 52/262 : taking into account adaptive modulation and coding [AMC] scheme AMC per se H04L1/0001
• CPC Class Codes: H04W 52/322 : Power control of broadcast channels
• CPC Class Codes: H04W 52/325 : Power control of control or pilot channels
• CPC Class Codes: H04W 52/343 : taking into account loading or congestion level
• CPC Class Codes: H04W 52/346 : distributing total power among users or channels
• CPC Class Codes: H04W 52/36 : with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/367 : Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 52/44 : in connection with interruption of transmission
• CPC Class Codes: H04W 52/50 : at the moment of starting communication in a multiple access environment
• CPC Class Codes: H04W 52/52 : using AGC [Automatic Gain Control] circuits or amplifiers
• CPC Class Codes: H04W 52/54 : Signalisation aspects of the TPC commands, e.g. frame structure
• CPC Class Codes: H04W 52/60 : using different transmission rates for TPC commands
• CPC Class Codes: Y02D 10/00 : Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A method and apparatus for communication data signal blocking for a base radio control station (RCS) which wirelessly communicates with subscriber units (SUs) via a spread spectrum communication system is disclosed. A transmitter sends signals as a baseband combined signal over global and assigned channels to SUs. The SUs are set to initial power levels and the power levels are adjusted in advance of receiving signals on assigned channels. The power levels are combined to define an RCS transmitter power level, which is preferably a root mean square value of the baseband combined signal. The transmission power levels are adjusted in response to corresponding power control signals received from the SUs. Transmission of a new communication data signal on an assigned channel is blocked if a predetermined RCS transmitter power level limit is reached before commencing transmission of that signal.

Claims

1. A method of communication data signal blocking for a base radio control station (RCS) which conducts wireless communication with subscriber units (SUs) in a spread spectrum communication system using code division multiple access, the method comprising:

providing a transmitter for transmitting signals over global and assigned channels to SUs which are initialized at initial power levels and adjusted to controlled power levels in advance of transmitting communication data signals on assigned channels to SUs which power levels combine to define an RCS transmitter power level, said transmitter transmitting signals as a baseband combined signal;

controlling the power levels of said transmitter signals to adjust the signal power levels in response to corresponding power control signals received from the SUs; and

monitoring a root mean square value of the baseband combined signal as the RCS transmitter power level and controlling the transmitter such that transmission of a new communication data signal on an assigned channel is blocked if a predetermined RCS transmitter power level limit is reached before commencing transmission of the new communication data signal.

2. The method of claim 1 wherein said transmitter transmits signals as a combined RF signal and a transmission power level the RF signal is monitored as the RCS transmitter power level.

3. The method of claim 1 wherein said transmitter transmits power control signals to adjust SU transmission power levels, the method further comprising the steps of:

monitoring signal power levels of signals received from an SU in advance of transmitting a communication data signal on an assigned channel to that SU to determine if power control signals transmitted to that SU have been implemented; and

controlling the transmitter such that transmission of a communication data signal on an assigned channel to that SU is blocked if it is determined that a power control signal to increase signal power of that SU has not been implemented before commencing transmission of the communication data signal on the assigned channel to that SU.

4. The method of claim 3 wherein said transmitter is configured to transmit a plurality of types of communication data signals including plain old telephone service (POTS), FAX and integrated services digital network (ISDN) and transmits power control signals to adjust SU transmission power levels on a global channel.

5. The method of claim 3 wherein said transmitter transmits signals as a combined RF signal and a transmission power level the RF signal is monitored as the RCS transmitter power level.

6. The method of claim 1 wherein said transmitter is configured to transmit a plurality of types of communication data signals including plain old telephone service (POTS), FAX and integrated services digital network (ISDN) on assigned channels by first providing a dial tone in conjunction with channel assignment, and said blocking the transmission of a new communication data signal on an assigned channel is done if a predetermined RCS transmitter power level limit is reached before a dial tone is provided.

7. The method of claim 6 wherein said transmitter transmits signals as a combined RF signal and a transmission power level the RF signal is monitored as the RCS transmitter power level.

8. A base radio control station (RCS) having subscriber unit (SU) blocking control for wireless communication with multiple SUs in a spread spectrum communication system using code division multiple access, the RCS comprising:

a transmitter for transmitting signals over global and assigned channels to SUs which are initialized at initial power levels and adjusted to controlled power levels in advance of transmitting communication data signals on assigned channels to SUs which power levels combine to define an RCS transmitter power level, said transmitter transmitting signals as a baseband combined signal;

a receiver and associated circuitry for controlling the power levels of said transmitter signals;

said receiver and associated circuitry configured to adjust the signal power levels in response to corresponding power control signals received from the SUs; and

control circuitry for monitoring the RCS transmitter power level and controlling the transmitter such that transmission of a new communication data signal on an assigned channel is blocked if a predetermined RCS transmitter power level limit is reached before commencing transmission of the new communication data signal, said control circuitry monitoring a root mean square value of the baseband combined signal as the RCS transmitter power level.

9. The RCS of claim 8 wherein said transmitter transmits signals as a combined RF signal and said control circuitry monitors a transmission power level the RF signal as the RCS transmitter power level.

10. The RCS of claim 8 wherein:

said transmitter is configured to transmit power control signals to adjust SU transmission power levels; and

said receiver and associated circuitry is configured to monitor signal power levels of signals received from an SU in advance of transmitting a communication data signal on an assigned channel to that SU to determine if power control signals transmitted to that SU have been implemented and to control said transmitter such that transmission of a communication data signal on an assigned channel to that SU is blocked if it is determined that a power control signal to increase signal power of that SU has not been implemented before commencing transmission of the communication data signal on the assigned channel to that SU.

11. The RCS of claim 10 wherein said transmitter is configured to transmit a plurality of types of communication data signals including plain old telephone service (POTS), FAX and integrated services digital network (ISDN).

12. The RCS of claim 10 wherein said transmitter is configured to transmit power control signals to adjust SU transmission power levels on a global channel.

13. The RCS of claim 10 wherein said transmitter transmits signals as a combined RF signal and said control circuitry monitors a transmission power level the RF signal as the RCS transmitter power level.

14. The RCS of claim 8 wherein said transmitter is configured to transmit a plurality of types of communication data signals including plain old telephone service (POTS), FAX and integrated services digital network (ISDN) on assigned channels by first providing a dial tone in conjunction with channel assignment, and said control circuitry blocks the transmission of a new communication data signal on an assigned channel if a predetermined RCS transmitter power level limit is reached before a dial tone is provided.