Channel adaptive fast power control in CDMA

• US 6,760,320 B1
• Filed: 04/21/1999
• Issued: 07/06/2004
• Est. Priority Date: 04/12/1999
• Status: Expired due to Term

• Current Assignee: WSOU Investments, LLC (WSOU Holdings, LLC)
• Original Assignee: Alcatel SA (Nokia Corporation)
• Inventors: Bune, Paul A. M.
• Primary Examiner(s): Olms, Douglas
• Assistant Examiner(s): Pizarro, Ricardo M.
• Application Number:
  US09/295,392
• Time in Patent Office: 1,903 Days
• Field of Search: 370/342, 370/343, 370/344, 370/346, 370/255, 370/319, 370/311, 370/310, 370/335, 375/130, 375/227, 455/517, 455/522, 455/452, 455/515
• US Class Current: 370/342
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/24 using SIR [Signal to Interference Ratio] or other wireless path parameters

Abstract

The invention relates to a method of channel-adaptive power control. According to the invention, the method makes it possible to control the transmission power in a channel-adapting way, employing an arbitrary large set of different TPC algorithms (TPCAs) for use. Each TPCA should be well adapted to a special kind of channel characteristics. The set of TPCAs is all the better performing when it covers the largest scale possible of channel characteristics. At any time, the transmission power is controlled by that algorithm chosen among the set of algorithms that appears to be optimal for the actual channel characteristics.

Claims

1. A method of controlling the power transmitted by a unit in a digital CDMA radio transmission system using a closed loop power control scheme based on an operative algorithm which generates commands to adapt the transmitted power according to the channel characteristics, comprising:

(a) processing at least one competitive algorithm different from said operative algorithm;

(b) evaluating a performance of all said algorithms according to a common quality criterion; and

(c) replacing the operative algorithm by one of said competitive algorithms if the latter shows better performance.

16. The method of claim 1, wherein the operative algorithm is replaced by a competitive algorithm immediately after determining that the competitive algorithm shows better performance than the operative algorithm and any other competitive algorithms.

17. The method of claim 1, wherein the operative algorithm is replaced by a competitive algorithm that shows better performance than the operative algorithm and any other competitive algorithms only if a quality of the competitive algorithm exceeds a predetermined threshold.

18. The method of claim 1, wherein the operative algorithm is replaced by a competitive algorithm that shows better performance than the operative algorithm and any other competitive algorithm only if the competitive algorithm shows the best performance for a predetermined period of time.

2. A method of controlling the power transmitted by a unit in a digital CDMA radio transmission system using a closed loop power control scheme based on an operative algorithm which generates commands to adapt the transmitted power according to the channel characteristics, comprising:

(a) processing at least one competitive algorithm different from said operative algorithm;

(b) evaluating a performance of all said algorithms according to a common quality criterion; and

(c) replacing the operative algorithm by one of said competitive algorithms if the latter shows better performance,

wherein the competitive algorithms are provided with information about the radio channel and simulate a behavior of each algorithm by computing simultaneously and independently of each other individual Transmission Power Control (TPC) commands.

3. The method of claim 2, wherein the common quality criterion determines in which extent the TPC commands generated by an algorithm enables it to approach a target transmission quality in the CDMA radio transmission system, while minimizing the transmitted power.

4. The method of claim 3, wherein a best fitting algorithm (Ak) is determined according to the common quality criterion and a switching between algorithms is triggered, the best fitting algorithm (Ak) becomes the operative algorithm, while the former operative algorithm is maintained as a competitive algorithm.

5. A method of controlling the power transmitted by a unit in a digital CDMA radio transmission system using a closed loop power control scheme based on an operative algorithm which generates commands to adapt the transmitted power according to the channel characteristics, comprising:

(a) processing at least one competitive algorithm different from said operative algorithm;

(b) evaluating a performance of all said algorithms according to a common quality criterion;

(c) replacing the operative algorithm by one of said competitive algorithms if the latter shows better performance; and

(d) using an algorithm for processing a measured Signal-to-Interference Ratio (SIR measured) in relation to a first threshold (SIR threshold) to generate a Transmission Power Control (TPC) command,

wherein a decrease of the transmitting power is required when the measured Signal-to-Interference Ratio (SIR measured) is increasing with a gradient above a defined threshold gradient and the measured Signal-to-Interference Ratio (SIR measured) is above a second threshold (pre-braking SIR).

6. A method of controlling the power transmitted by a unit in a digital CDMA radio transmission system using a closed loop power control scheme based on an operative algorithm which generates commands to adapt the transmitted power according to the channel characteristics, comprising:

(a) processing at least one competitive algorithm different from said operative algorithm;

(b) evaluating a performance of all said algorithms according to a common quality criterion;

(c) replacing the operative algorithm by one of said competitive algorithms if the latter shows better performance; and

(d) using an algorithm for processing a measured Signal-to-Interference Ratio (SIR measured) and an estimated Absolute or Relative Channel Loss (ACL measured, RCL measured) in relation to a first threshold (SIR threshold) to generate a Transmission Power Control (TPC) command,

wherein a decrease of the transmitting power is required when the Absolute or Relative Channel Loss (ACL measured, RCL measured) is decreasing with a gradient below a defined threshold gradient and the measured Signal-to-Interference Ratio (SIR measured) is above a second threshold (pre-braking SIR).

7. A digital radio communication system based on CDMA comprising:

(a) at least one transmitter;

(b) at least one receiver; and

(c) a controller controlling a transmission power,

wherein an estimation unit (41) measures and processes a channel signal, a reconstruction unit (42) provides a pure channel information, an operating unit (43) generates Transmission Power Control commands, n simulation units (441 . . . 44n) compute a set of competitive algorithms, and a selection unit (45) activates one algorithm out of the set of the competitive algorithms.

8. A transceiver device for a digital CDMA radio communication channel comprising a control circuit (4) for controlling a transmission power, wherein an estimation unit (41) measures and processes a channel signal, a reconstruction unit (42) provides a pure channel information, an operating unit (43) generates Transmission Power Control commands, n simulation units (441 . . . 44n) compute a set of competitive algorithms, and a selection unit (45) activates one algorithm out of the set of the competitive algorithms.

9. The transceiver device of claim 8, wherein said transceiver device is comprised in a mobile station.

10. The transceiver device of claim 8, wherein said transceiver device is comprised in a base station.

11. A digital radio communication system based on CDMA comprising:

(a) at least one transmission means;

(b) at least one reception means;

(c) a control means for controlling a transmission power,

(d) an estimation means for measuring and processing a channel signal;

(e) a reconstruction means for providing a pure channel information;

(f) an operation means for generating Transmission Power Control commands;

(g) n simulation means for computing a set of competitive algorithms; and

(h) a selection means for activating one algorithm out of the set of competitive algorithms.

12. The digital communication system of claim 11, wherein the selection means activates the algorithm providing optimal power control.

13. A transceiver device for a digital CDMA radio communication channel comprising:

(a) a control means for controlling a transmission power;

(b) an estimation means for measuring and processing a channel signal;

(c) a reconstruction means for providing a pure channel information;

(d) an operation means for generating Transmission Power Control commands;

(e) n simulation means for computing a set of competitive algorithms; and

(f) a selection means for activating one algorithm out of the set of competitive algorithms.

14. The transceiver device of claim 13, wherein the selection means activates the algorithm providing optimal power control.

15. A method of controlling the power transmitted by a unit in a digital CDMA radio transmission system using a closed loop power control scheme based on an operative algorithm which generates commands to adapt the transmitted power according to the channel characteristics, comprising:

(a) processing at least one competitive algorithm different from said operative algorithm;

(b) evaluating a performance of all said algorithms according to a common quality criterion; and

(c) replacing the operative algorithm by one of said competitive algorithms if the latter shows better performance,

wherein the evaluation of the performance of all said algorithms, according to a common quality criteria, occurs in parallel.