Cooperative transmission power control method and system for CDMA communication systems

• US 6,954,622 B2
• Filed: 01/29/2002
• Issued: 10/11/2005
• Est. Priority Date: 01/29/2002
• Status: Active Grant

• Current Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Original Assignee: L-3 Communications Corporation (L3Harris Technologies, Inc.)
• Inventors: Nelson, David S., Horne, Lyman D., Jones, Delon K.
• Primary Examiner(s): Maung, Nay
• Assistant Examiner(s): Perez, Angelica
• Application Number:
  US10/059,938
• Publication Number:
  US 20030144019A1
• Time in Patent Office: 1,351 Days
• Field of Search: 455/127, 455/522, 455/69, 455/13.1, 455/513, 455/574, 455/572
• US Class Current: 455/127.1
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/226 using past references to control power, e.g. look-up-table
• CPC Class Codes: H04W 52/228 using past power values or information
• CPC Class Codes: H04W 52/54 Signalisation aspects of the TPC commands, e.g. frame structure

Abstract

A method and system for cooperative transmission power control in a communication system is provided. The method, operating within a system having a base station and at least on mobile station, includes the step of providing a power control data structure having memory fields indexed according to a predetermined parameter set. The next step retrieves from one of the memory fields a transmission power control value and adjusts a transmission power level of the mobile station according to the retrieved value.

Claims

1. A method for cooperative transmission power control in a communication system having a first and a second transceiver device, the method comprising the steps of:

providing a power control data structure, the power control data structure comprising memory fields indexed according to a predetermined parameter set;

wherein the step of retrieving from one of the memory fields the transmission power control value further comprises the step of accessing the power control data structure according to an automatic gain control (AGC), a PN code correlation accumulator (PNCA) parameter, and an ambient receiver temperature parameter;

retrieving from one of the memory fields a transmission power control value; and

using the retrieved transmission power control value to adjust a transmission power level of the second transceiver device.

2. A method as in claim 1 wherein the step of providing the power control data structure further comprises the step of providing at least one power control table.

3. A method as in claim 1 wherein the step of retrieving from one of the memory fields the transmission power control value further comprises the steps of:

determining if the accessed memory field is null, and in response to a null determination executing the following steps;

determining a number of transmission bursts since transmitted, and in response to the determined number of transmission bursts;

if the number of bursts since transmitted is below a predetermined value then using a previous transmission power control value, wherein the previous transmission power control value comprises the last transmission power control value;

if the number of bursts since transmitted is above the predetermined value then selecting at least one transmission power control value from an alternate memory field and deriving a current transmission power control value;

deriving the current transmission power control value based upon the previous transmission power control value and whether or not the receiver device is entering or leaving a signal fade region if the at least one transmission power control value is also null; and

populating the accessed memory field with the current transmission power control value.

4. A method as in claim 1 wherein the step of providing the power control data structure further comprises the steps of:

receiving a power command table update from the first transceiver device, wherein the power command table update is directed to at least one memory field within the power control data structure;

adjusting the at least one memory field in accordance with the received power command table update from the first transceiver device; and

limiting the adjusted memory field to a predetermined threshold in response to determining the adjusted memory field exceeds the predetermined threshold.

5. A method as in claim 4 wherein the step of limiting the adjusted memory field to the predetermined threshold further comprises the step of sending a message to the first transceiver device.

6. A method as in claim 4 wherein the step of receiving the power command table update from the first transceiver device further comprises the steps of:

determining a noise level at the first transceiver device;

determining a difference between the noise level and a predetermined noise target;

converting the difference to a power command table update; and

transmitting the power command table update to the receiver device.

7. A method as in claim 6 wherein the step of determining the noise level at the first transceiver device further comprises the step of finding a pseudo-noise correlation squared sum (PNSS) of a received PN code.

8. A method as in claim 1 wherein the communications systems further comprises a code division multiple access (CDMA) communication system.

9. A system for controlling transmission power level of a plurality of receiver devices in a code division multiple access (CDMA) communication system having at least one access point device, the system comprising:

a plurality of at least two receivers;

each receiver device comprising;

a receiver device memory device for storing, according to a predetermined parameter set that comprises an automatic gain control value (AGC), an ambient temperature value, and a PN correlation accumulator (PNCA) value, a

plurality of receiver device transmission power values for the respective receiver device;

a receiver device memory access controller for accessing the receiver device memory device;

a receiver device memory controller for updating the receiver device memory device; and

access point device memory controller for updating the plurality of receiver device transmission power values.

10. A system as in claim 9 wherein each receiver device further comprises a temperature controller for determining ambient temperature.

11. A system as in claim 9 wherein the receiver device memory access controller comprises at least one open loop memory access controller.

12. A method for controlling receiver device transmission power in a communications system, the communication system having an access point device and a plurality of receiver devices, the method comprising the steps of:

providing each receiver device a transmission power level look-up table that relates transmission power to a set of parameters that include an automatic gain control value (AGC), an ambient temperature value, and a PN correlation accumulator (PNCA) value;

providing each receiver device an open-loop power control model; and

accessing the transmission power level look-up table with the open-loop power control model setting the transmit power according to said model.

13. A method as in claim 12 wherein the step of providing each receiver device the transmission power level look-up table further comprises the steps of:

at the access point device;

determining a received power level from one of the plurality of receiver devices;

determining a transmission power deviation for that receiver device;

transmitting a first update value based derived from the transmission power deviation to the receiver device; and

at the receiver device, using the first update value to update the transmission power level look-up table.

14. A method as in claim 13 wherein the step of determining at the base station the received power level further comprises the steps of:

accumulating a predetermined number of pseudo noise (PN) code correlations; and

squaring the sum of the predetermined number of PN code correlations (PNCSS).

15. A method as in claim 14 wherein the step of determining the transmission power deviation further comprises the step of comparing PNCSS to a predetermined target value.

16. A method as in claim 15 wherein the step of determining the transmission power deviation further comprises the step of determining the transmission power deviation according to:

 

deviation=(PNCSS*2{circumflex over (0)}(SF)−

Target)*2{circumflex over (0)}(−

Shift).

17. A method as in claim 16 wherein the step of using the first update value to update the transmission power level look-up table further comprises the steps of:

determining if the first update value exceeds a predetermined range; and

adjusting the first update value to closest range limit if determining the first update value exceeds the predetermined range.