Subchannel control loop

• US 5,991,284 A
• Filed: 02/13/1997
• Issued: 11/23/1999
• Est. Priority Date: 02/13/1997
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Willenegger, Serge, Jou, Yu-Chen
• Primary Examiner(s): NGO, RICKY QUOC
• Application Number:
  US08/800,734
• Time in Patent Office: 1,013 Days
• Field of Search: 370/206, 370/208, 370/252, 370/310, 370/311, 370/313, 370/328, 370/329, 370/335, 370/342, 370/441, 370/336, 370/337, 370/341, 370/347, 370/442, 375/200, 375/206, 375/208, 455/69, 455/522, 455/103, 455/127, 455/38.1, 455/38.3, 455/501, 455/517, 455/63, 455/67.1, 455/68, 455/70
• US Class Current: 370/335
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/288 taking into account the usage mode, e.g. hands-free, data transmission, telephone
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

Independently controlling the transmitted power of each subchannel by a subchannel control loop is described. A transmitting station generates a channel made up of a sum of subchannels wherein each subchannel or group of subchannels is amplified with a unique gain value that is varied in accordance with subchannel power control messages from the receiving station. The receiving station generates each subchannel power control message subsequent to monitoring and calculating metrics based on that received subchannel.

Claims

1. In a wireless communication system in which a remote station transmits a reverse link signal comprising a plurality of subchannel signals, a power control subsystem located in a base station for independently adjusting the transmission power of one or more of said plurality of subchannel signals, comprising:

a receiver that receives said reverse link signal;

a demodulator that demodulates said reverse link signal to provide said plurality of subchannel signals, including;

a PN demodulator that demodulates said reverse link signal in accordance with a pseudorandom noise (PN) sequence to provide a remote station signal; and

a plurality of orthogonal demodulators, each of which receives said remote station signal and demodulates said remote station signal in accordance with an orthogonal demodulation sequence to provide a corresponding one of said subchannel signals; and

a message generator that generates a power control message for adjusting the transmit power of at least one of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding one of said subchannel signals.

9. The power control subsystem of claim 1 further comprising:

a plurality of accumulators, wherein each of said accumulators receives a corresponding one of said subchannel signals and accumulates the energy of said subchannel signal for a predetermined period of time to provide an accumulated subchannel energy; and

a comparator that receives said accumulated subchannel energies and compares each of said accumulated subchannel energies with a corresponding threshold value of a plurality of threshold values.

10. The power control subsystem of claim 1 further comprising:

a plurality of decoders, wherein each of said decoders receives a corresponding subchannel signal and determines the existence of frame errors in said subchannel signal; and

a comparator that compares a frame error rate based on said determined frame errors with a frame error rate threshold.

11. The power control subsystem of claim 9 further comprising:

a threshold generator that generates said plurality of threshold values in accordance with a measured frame error rate for each of said subchannel signals.

12. The power control system of claim 1 wherein said power control message comprises:

a plurality of bits, wherein each bit represents a command to increase or decrease the transmit power of said subchannel signal by a predetermined amount.

13. The power control system of claim 1 wherein said power control message comprises:

a plurality of gain values, wherein each gain value is applied to one of said plurality of subchannel signals to control the transmit power of said subchannel signal.

14. The power control system of claim 1 wherein said power control message comprises:

a plurality of values, wherein each value is made up of more than one bit and fewer than the number required to determine the entire gain value, and each of said plurality of values represents a command to increase or decrease the transmit power of said subchannel signal by said value multiplied by a predetermined amount.

15. The power control system of claim 1 further comprising:

a modulator that modulates said power control message in accordance with a modulation format.

16. The power control system of claim 15 wherein said modulator comprises:

a modulator that modulates said power control message in accordance with a CDMA format.

2. In a wireless communication system in which a remote station transmits a reverse link signal comprising a plurality of subchannel signals, a power control subsystem located in a base station for independently adjusting the transmission power of one or more of said plurality of subchannel signals, comprising:

a receiver that receives said reverse link signal;

a demodulator that demodulates said reverse link signal to provide said plurality of subchannel signals;

a message generator that generates a power control message for adjusting the transmit power of at least one of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding one of said subchannel signals

a plurality of accumulators, wherein each of said accumulators receives a corresponding one of said subchannel signals and accumulates the energy of said subchannel signal for a predetermined period of time to provide an accumulated subchannel energy; and

a comparator that receives said accumulated subchannel energies and compares each of said accumulated subchannel energies with a corresponding threshold value of a plurality of threshold values.

4. The power control subsystem of claim 2 further comprising:

a threshold generator that generates said plurality of threshold values in accordance with a measured frame error rate for each of said subchannel signals.

3. In a wireless communication system in which a remote station transmits a reverse link signal comprising a plurality of subchannel signals, a power control subsystem located in a base station for independently adjusting the transmission power of one or more of said plurality of subchannel signals, comprising:

a receiver that receives said reverse link signal;

a demodulator that demodulates said reverse link signal to provide said plurality of subchannel signals;

a message generator that generates a power control message for adjusting the transmit power of at least one of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding one of said subchannel signals;

a plurality of decoders, wherein each of said decoders receives a corresponding subchannel signal and determines the existence of frame errors in said subchannel signal; and

a comparator that compares a frame error rate based on said determined frame errors with a frame error rate threshold.

5. In a wireless communication system in which a remote station transmits a reverse link signal comprising a plurality of subchannel signals, a power control subsystem located in a base station for independently adjusting the transmission power of one or more of said plurality of subchannel signals, comprising:

a receiver that receives said reverse link signal;

a demodulator that demodulates said reverse link signal to provide said plurality of subchannel signals;

a message generator that generates a power control message for adjusting the transmit power of at least one of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding one of said subchannel signals; and

a plurality of bits, wherein each bit represents a command to increase or decrease the transmit power of said subchannel signal by a predetermined amount.

6. In a wireless communication system in which a remote station transmits a reverse link signal comprising a plurality of subchannel signals, a power control subsystem located in a base station for independently adjusting the transmission power of one or more of said plurality of subchannel signals, comprising:

a receiver that receives said reverse link signal;

a demodulator that demodulates said reverse link signal to provide said plurality of subchannel signals;

a message generator that generates a power control message for adjusting the transmit power of at least one of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding one of said subchannel signals, and

a plurality of gain values, wherein each gain value is applied to one of said plurality of subchannel signals to control the transmit power of said subchannel signal.

7. In a wireless communication system in which a remote station transmits a reverse link signal comprising a plurality of subchannel signals, a power control subsystem located in a base station for independently adjusting the transmission power of one or more of said plurality of subchannel signals, comprising:

a receiver that receives said reverse link signal;

a demodulator that demodulates said reverse link signal to provide said plurality of subchannel signals;

a message generator that generates a power control message for adjusting the transmit power of at least one of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding one of said subchannel signals, and

a plurality of values, wherein each value is made up of more than one bit and fewer than the number required to determine the entire gain value, and each of said plurality of values represents a command to increase or decrease the transmit power of said subchannel signal by said value multiplied by a predetermined amount.

8. In a wireless communication system in which a remote station transmits a reverse link signal comprising a plurality of subchannel signals, a power control subsystem located in a base station for independently adjusting the transmission power of one or more of said plurality of subchannel signals, comprising:

a receiver that receives said reverse link signal;

a demodulator that demodulates said reverse link signal to provide said plurality of subchannel signals; and

a message generator that generates a power control message for adjusting the transmit power of at least one of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding one of said subchannel signals; and

a modulator that modulates said power control message in accordance with a CDMA format.

17. In a wireless communication system in which a remote station transmits a reverse link signal comprising a plurality of subchannel signals, a power control subsystem located in a base station for independently adjusting the transmission power of one or more of said plurality of subchannel signals, comprising:

a receiver that receives said reverse link signal;

a demodulator that demodulates said reverse link signal to provide said plurality of subchannel signals; and

a message generator that generates a power control message for adjusting the transmit power of at least one of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding one of said subchannel signals, and wherein said message generator generates a power control message for adjusting the transmit power of two of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding two of said subchannel signals.

18. In a wireless communication system in which a remote station transmits a reverse link signal comprising a plurality of subchannel signals, a power control subsystem located in a base station for independently adjusting the transmission power of one or more of said plurality of subchannel signals, comprising:

a receiver that receives said reverse link signal;

a demodulator that demodulates said reverse link signal to provide said plurality of subchannel signals; and

a message generator that generates a power control message for adjusting the transmit power of at least one of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding one of said subchannel signals, and wherein said message generator generates a power control message for adjusting the transmit power of three of said plurality of subchannel signals in accordance with a quality measurement or an energy measurement associated with a corresponding three of said subchannel signals.