Fast adaptive power control for a variable multirate communications system

• US 6,823,194 B2
• Filed: 07/12/2001
• Issued: 11/23/2004
• Est. Priority Date: 07/26/2000
• Status: Expired due to Term

• Current Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Original Assignee: Interdigital Technology Corporation (InterDigital, Inc.)
• Inventors: Haim, John W.
• Primary Examiner(s): Corsaro, Nick
• Assistant Examiner(s): TRINH, TAN H
• Application Number:
  US09/904,001
• Publication Number:
  US 20020027959A1
• Time in Patent Office: 1,230 Days
• Field of Search: 455/522, 455/70, 455/296, 455/69, 455/39, 455/517, 455/571, 455/226.1
• US Class Current: 455/522
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/10 Open loop power control
• CPC Class Codes: H04W 52/12 Outer and inner loops
• 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 52/242 taking into account path loss
• CPC Class Codes: H04W 52/265 taking into account the quality of service QoS
• CPC Class Codes: H04W 52/267 taking into account the information rate
• CPC Class Codes: H04W 52/362 Aspects of the step size

Abstract

A system and a method of controlling transmitter power in a wireless communication system in which user data is processed as a multirate signal having a rate N(t) and in which the user data signal having rate N(t) is converted into a transmission data signal having a faster rate M(t) for transmission. The transmission power is adjusted on a relatively slow basis based on quality of data received by a receiver of the transmitted data. The transmitter power is determined as a function of N(t)/M(t) such that a change in the data rate in the multiple channels or the rate of the transmission data signal is compensated in advance of a quality of data based adjustment associated with such data rate change. Preferably, the user data signal having rate N(t) is converted into the transmission data signal having the faster rate M(t) by repeating selected data bits whereby the energy per bit to noise spectrum density ratio is increased in the transmission data signal.

Claims

1. A method of controlling transmitter power in a wireless communication system in which user data is processed in a multirate signal having a rate N(t) where N(t) is a function time and in which the user data signal having rate N(t) is converted into a transmission data signal having a faster rate M(t) for transmission by a transmitter and in which the transmission power is adjusted on a relatively slow basis based on quality of data received by a receiver of the transmitted data comprising determining a transmitter scale factor as a function of N(t)/M(t) such that a change in the user data signal rate or the rate of the transmission data signal is compensated for in advance of a quality of data based adjustment associated with such data rate change wherein transmitter power is controlled by an open loop system where the transmitter:

receives from the receiver a reference signal, reference signal power data, measured interference power data, and target signal to interference ratio (SIR) data which SIR data is based on relatively slowly collected received signal quality data,

measures the reference signal to determine received reference signal power,

computes a path loss based on the received reference signal power data and the determined reference signal power, and

computes the scale factor based on the computed path loss, the received measured interference power data, the target SIR data and (N(t)/M(t)).

2. The method of claim 1 wherein the user data signal having rate N(t) is converted into the transmission data signal having the faster rate M(t) by repeating selected data bits whereby the energy per bit to noise spectrum density ratio is increased in the transmission data signal.

3. A method of controlling transmitter power in a wireless communication system in which user data is processed in a multirate signal having a rate N(t) where N(t) is a function time and in which the user data signal having rate N(t) is converted into a transmission data signal having a faster rate M(t) for transmission by a transmitter and in which the transmission power is adjusted on a relatively slow basis based on quality of data received by a receiver of the transmitted data comprising determining a transmitter scale factor as a function of N(t)/M(t) such that a change in the use data signal rate or the rate of the transmission data signal is compensated for in advance of a quality of data based adjustment associated with such data rate change wherein transmitter power is controlled by a closed loop system where the transmitter utilizes step up/down data generated by the receiver and compute the scale factor based on the step up/step down data and (N(t)/M(t)).

4. The method of claim 3 wherein the user data signal having rate N(t) is converted into the transmission data signal having the faster rate M(t) by repeating selected data bits whereby the energy per bit to noise spectrum density ratio is increased in the transmission data signal.

5. The method of claim 3 wherein the step up/down data is generated by the receiver by combining measured interference power data of the signal received from the transmitter with target signal to interference ratio (SIR) data based at least in part on relatively slowly collected received signal quality data.

6. The method of claim 5 wherein the target SIR data is computed by multiplying a nominal target SIR data based on relatively slowly collected received signal quality data by a factor N(t)/M(t) so that the target SIR data is quickly adjusted when a change in data rate occurs.

7. The method of claim 6 wherein the user data signal having rate N(t) is converted into the transmission data signal having the faster rate M(t) by repeating selected data bits whereby the energy per bit to noise spectrum density ratio is increased in the transmission data signal.

8. A method of controlling transmitter power in a wireless communication system in which user data is processed in a multirate signal having a rate N(t) where N(t) is a function time and in which the user data signal having rate N(t) is converted into a transmission data signal having a faster rate M(t) for transmission by a transmitter and in which the transmission power is adjusted on a relatively slow basis based on quality of data received by a receiver of the transmitted data comprising determining a transmitter scale factor as a function of N(t)/M(t) such that a change in the user data signal rate or the rate of the transmission data signal is compensated for in advance of a quality of data based adjustment associated with such data rate change wherein the user data signal having rate N(t) is converted into the transmission data signal having the faster rate M(t) by repeating selected data bits whereby the energy per bit to noise spectrum density ratio is increased in the transmission data signal.

9. A transmitter for a wireless communication system in which user data is processed as a multirate signal having a rate N(t) where N(t) is a function time and in which the user data signal having rate N(t) is converted into a transmission data signal having a faster rate M(t) for transmission and in which transmission power is adjusted on a relatively slow basis by applying a scale factor to the transmitter power based on quality of data received by a receiver of the transmitted data comprising:

a data signal rate converter which increases the user data signal rate N(t) to a higher data transmission rate M(t);

a processor for computing a transmission power scale factor based in part on data generated by the receiver related to quality of data received; and

said data signal rate converter associated with said processor such that said processor computes the transmission power scale factor as a function of N(t)/M(t) whereby a change in the data rate in the multiple channels or the rate of the transmission data signal is compensated for in advance of a receiver quality of data based adjustment associated with such data rate change.

10. The transmitter of claim 9 wherein said data signal rate converter converts the user data signal having rate N(t) into the transmission data signal having the faster rate M(t) by repeating selected data bits whereby the energy per bit to noise spectrum density ratio is increased in the transmission data signal.

11. The transmitter of claim 9 having an open loop power control system where the transmitter receives from the receiver of the transmitted data:

a reference signal, reference signal power data, measured interference power data, and target signal to interference ratio (SIR) data which SIR data is based on relatively slowly collected received signal quality data, further comprising;

a signal measuring device which measures received reference signal power, path loss processing circuitry for computing a path loss based on the received reference signal power data and the measured received reference signal power, and said processor computes the transmission power scale factor based on the computed path loss, the received measured interference power data, the target SIR data and (N(t)/M(t)).

12. The transmitter of claim 11 wherein said data signal rate converter converts the user data signal having rate N(t) into the transmission data signal having the faster rate M(t) by repeating selected data bits whereby the energy per bit to noise spectrum density ratio is increased in the transmission data signal.

13. The transmitter of claim 9 having a closed loop power control system where the transmitter receives step up/down data on the receiver of the transmitted data wherein said processor computes the transmission power scale factor based on the received step up/step down data and (N(t)/M(t)).

14. The transmitter of claim 13 wherein said data signal rate converter converts the user data signal having rate N(t) into the transmission data signal having the faster rate M(t) by repeating selected data bits whereby the energy per bit to noise spectrum density ratio is increased in the transmission data signal.

15. A method of controlling transmitter power in a wireless communication system in which user data is processed as a multirate signal having a rate N(t) where N(t) is a function time and in which the combined multichannel signal having rate N(t) is converted into a transmission data signal having a faster rate M(t) for transmission by a transmitter and in which the transmission power is adjusted on a relatively slow basis based on quality of data received by a receiver of the transmitted data comprising:

determining the transmitter scale factor as a function of N(t)/M(t) such that a change in the data rate in the multiple channels or the rate of the transmission data signal is compensated in advance of a quality of data based adjustment associated with such data rate change.

16. The method of claim 15 wherein the user data signal having rate N(t) is converted into the transmission data signal having the faster rate M(t) by repeating selected data bits whereby the energy per bit to noise spectrum density ratio is increased in the transmission data signal.