Device and method for controlling initial transmission power of forward link channel in mobile communications system

• US 6,643,520 B1
• Filed: 08/02/1999
• Issued: 11/04/2003
• Est. Priority Date: 08/01/1998
• Status: Expired due to Fees

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Park, Jin-Soo, Kim, Young-Ky, Ahn, Jae-Min
• Primary Examiner(s): Nguyen, Lee
• Assistant Examiner(s): GELIN, JEAN ALLAND
• Application Number:
  US09/366,013
• Time in Patent Office: 1,555 Days
• Field of Search: 455/13.4, 455/511-515, 455/522, 455/69, 455/70, 455/571, 455/572, 455/574, 455/127, 455/136, 455/138, 455/67.1, 455/423, 370/318, 370/252, 370/320, 370/342, 370/441, 375/136, 375/146, 375/367
• US Class Current: 455/522
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment

Abstract

Devices and methods are provided for determining an initial transmission power for a forward link channel transmitter of a base station in a mobile communications system. A preferred method includes the steps of measuring, at a mobile station, the strength of a specified forward link channel signal received from the base station and sending information indicative of the strength of the specified forward link channel signal to the base station; and determining, at the base station, the initial transmission power for the specified forward link channel signal according to the information received from the mobile station and using the determined transmission power for controlling an initial transmission power for an other forward link channel.

Claims

1. A method for determining an initial transmission power for a forward link channel transmitter of a base station in a mobile communications system, comprising the steps of:

measuring, at a mobile station, a strength of a specified forward link channel received from the base station and sending information indicative of the strength of the specified forward link channel to the base station, wherein the strength is measured according to a ratio of the received power of the specified forward link channel to the received power of other channels; and

determining, at the base station, the initial transmission power for the specified forward link channel based on information received from the mobile station, including the ratio of the received power of the specified forward link channel to the received power of the other channels, and using the determined transmission power for controlling an initial transmission power for an other forward link channel.

2. The method as claimed in claim 1, wherein the specified forward link channel is a pilot channel.

3. The method as claimed in claim 2, wherein the step of measuring comprises the substeps of:

despreading signals received from the base station to measure energy per pilot channel chip;

measuring total received power spectral density of the signals received from the base station; and

determining the strength of the pilot channel signal according to a ratio of the energy per pilot chip to the total received power spectral density.

4. The method as claimed in claim 3, wherein the step of determining the initial transmission power comprises the substeps of:

calculating, at the base station, a ratio of a desired base station signal to interference and noise for other base stations using the ratio of the transmit energy per pilot channel chip to the total transmit power spectral density and the strength of the pilot channel signal; and

determining the initial transmission power for the other forward link channel from the ratio of the desired base station signal to the interference and noise for the other base stations.

5. The method as claimed in claim 3, wherein the step (2) of determining the initial transmission power comprises the steps of:

receiving from the mobile station the ratio of the energy per pilot channel chip to the total receiving power spectral density as the strength of the pilot channel signal; and

receiving the strength of the pilot channel signal and determining the initial transmission power to be proportional to a difference between the ratio of a required energy per the forward link channel signal bit to noise power spectral density and the strength of the pilot channel signal.

6. The method as claimed in claim 1, wherein the initial transmission power is an initial transmission power for a traffic channel.

7. The method as claimed in claim 1, wherein the initial transmission power is an initial transmission power for a control channel.

8. A method for determining an initial transmission power for a forward link channel transmitter of a base station in a mobile communications system, comprising the steps of:

sending, at a mobile station, information indicating a specified reverse link channel signal and a transmission power of the specified reverse link channel signal;

measuring, at the base station, a received power of the specified reverse link channel signal and determining the initial transmission power to be proportional to a difference between the transmission power included in the information received from the mobile station and the received power; and

sending a forward link channel signal with the initial transmission power.

9. The method as claimed in claim 8, wherein the specified reverse link channel is a pilot channel.

10. A mobile communications system for determining an initial transmission power for a forward link channel, comprising:

a mobile station for measuring a received power of a specified forward link channel and a received power of other channels and detecting a strength of the specified forward link channel according to a ratio of the received power of the specified forward link channel to the received power of the other channels; and

a base station for receiving the strength of the specified forward link channel, determining the initial transmission power according to the ratio and using the determined transmission power for controlling an initial transmission power for an other forward link channel.

11. The system as claimed in claim 10, wherein the specified forward link channel is a pilot channel.

12. The system as claimed in claim 11, wherein the mobile station comprises:

a power measurer comprising a pilot power measurer for despreading signals received from the base station and measuring energy per pilot channel chip, a total power measurer for measuring total power spectral density of signals received from the base station, and a pilot channel strength determiner for determining a strength of the pilot channel according to a ratio of the energy per pilot channel chip to the total received power spectral density; and

an access channel transmitter for sending the strength of the pilot channel through a reverse link access channel.

13. The system as claimed in claim 11, wherein the base station comprises:

a pilot channel transmitter for sending the pilot channel with fixed power;

a memory for storing the ratio of the transmit energy per pilot chip to the total transmission power spectral density;

a transmission power controller for calculating a ratio of a desired base station signal to interference and noise of other base stations using the strength of the pilot channel received from the mobile station, and determining an initial transmission power for the other forward link channel from the ratio of the desired base station signal to interference and noise of the other base stations; and

a forward link channel transmitter for transmitting a channel signal with the initial transmission power for the other forward link channel as determined by the transmission power controller.

14. The system as claimed in claim 11, wherein the base station comprises:

an access channel receiver for receiving the ratio of energy per pilot channel bit to total received noise power spectral density from the mobile station;

a memory for storing a ratio of required energy per forward link pilot channel bit to the total received noise power spectral density;

a transmission power controller for determining the initial transmission power by subtracting the ratio of the required energy per forward link pilot channel bit to the total received noise power spectral density and using the determined initial transmission power for the pilot channel; and

a forward link channel transmitter for transmitting a channel signal via the pilot channel with the initial transmission power determined by the transmission power controller.

15. The system as claimed in claim 10, wherein the initial transmission power is an initial transmission power for a traffic channel.

16. The system as claimed in claim 10, wherein the initial transmission power is an initial transmission power for a control channel.

17. A device for determining initial transmission power for a forward link channel in a mobile communications system, comprising:

a base station for sending a specified reverse link channel signal and transmission power for the specified reverse link channel signal,

wherein the base station measures received power of the specified reverse link channel signal, subtracts the measured received power from the transmission power of the specified reverse link channel to determine the initial transmission power, and uses the determined transmission power for controlling an initial transmission power for an other forward link channel.

18. The device as claimed in claim 17, wherein the specified reverse link channel is a pilot channel.

19. The device as claimed in claim 18, wherein the base station comprises:

a pilot transmitter for transmitting the reverse link pilot channel signal; and

an access channel transmitter for transmitting the transmission power of the reverse link pilot channel via a reverse link access channel message.

20. The device as claimed in claim 19, wherein the base station comprises:

a power measurer for measuring the received power of the reverse link pilot channel;

an access channel receiver for extracting the transmission power of the reverse link pilot channel from the reverse link access channel message;

a subtracter for subtracting the received power of the reverse link pilot channel from the transmission power of the reverse link pilot channel;

a transmission power controller for determining the initial transmission power of the reverse link pilot channel according by determining a difference between the transmission power and the received power of the reverse link pilot channel; and

a forward link channel transmitter for transmitting a channel signal with the initial transmission power determined for the reverse link pilot channel by the transmission power controller.

21. The device as claimed in claim 19, wherein the initial transmission power is an initial transmission power for a traffic channel.

22. The device as claimed in claim 19, wherein the initial transmission power is an initial transmission power for a control channel.

24. The method as claimed in claim 22, wherein the value (Ec/lor)_traffic_tx is in inverse proportion to the value (lor/(loc+No))_rx.

23. A method for determining an initial transmission power for a forward link channel in a mobile communication system, comprising the steps of:

at a mobile station, despreading a forward link channel signal received from a base station to measure energy per pilot channel chip and total received power spectral density of signals received from the base station, determining the strength of a pilot channel signal as (Ec/lo)_pilot_rx and sending the calculated strength of the pilot channel signal to a reverse link control channel;

at the base station, receiving the strength of the pilot channel signal and calculating the ratio (lor/(loc+No))_rx of a desired base station signal to interference and noise of other base stations using a ratio (Ec/lor)_pilot_tx of the transmit energy Ec per pilot channel chip to total transmission power spectral density lor, and the strength of the pilot channel signal according to the equation;

25. A method for determining an initial transmission power for a forward link channel in a mobile communications system, comprising the steps of:

at a mobile station, measuring energy Ec per pilot channel bit of a forward channel signal received from a base station and total received noise power spectral density Nt to determine a strength of a pilot channel signal as (Eb/Nt)_pilot_rx and sending the strength of the pilot channel signal to a reverse link control channel;

at the base station, receiving the strength of the pilot channel signal, comparing the strength of the pilot channel signal with a ratio (Eb/Nt)_required of required energy Eb per forward link channel signal bit to noise power spectral density Nt, and determining the initial transmission power according to the equation expressed by

26. A method for determining an initial transmission power for a forward link channel signal at a base station in a mobile communications system, comprising the steps of:

sending the forward link channel signal via a specified forward link channel and receiving information indicating a strength of the forward link channel signal from a mobile station;

determining the initial transmission power for the forward link channel according to the information about the strength of the forward link channel signal, and according to one of a total transmission power spectral density and the total noise power spectral density; and

sending signals via the specified forward link channel with the determined initial transmission power.

27. The method as claimed in claim 26, wherein the specified forward link channel is a pilot channel.

28. The method as claimed in claim 27, wherein the step of determining the initial transmission power comprising the substeps of:

calculating a ratio of a desired base station signal to interference and noise of other base stations, using a ratio of the transmit energy per pilot channel chip to a total transmission power spectral density and the strength of the pilot channel signal received from the mobile station; and

determining the initial transmission power for the forward link channel signal from the calculated ratio of the desired base station signal to the interference and noise of the other base stations.

29. The method as claimed in claim 27, wherein the step of determining the initial transmission power comprising the substeps of:

receiving a ratio of energy per pilot channel bit to a total noise power spectral density as the strength of the pilot channel signal from the mobile station; and

receiving the strength of the pilot channel signal and determining the initial transmission power for the forward link channel signal to be proportional to a difference between a ratio of energy per required forward channel bit to the total noise power spectral density and the strength of the pilot channel signal.

30. The method as claimed in claim 26, wherein the initial transmission power is an initial transmission power for a traffic channel.

31. The method as claimed in claim 26, wherein the initial transmission power is an initial transmission power for a control channel.

32. A method for communicating a channel in a mobile communications system, comprising the steps of:

receiving a specified forward link channel signal;

despreading the specified forward link channel signal to measure energy per forward link channel chip and measuring total received power spectral density of all forward link signals received;

determining a received power value according to a ratio of the energy per forward link channel chip for the specified forward link channel signal and the total receiving power spectral density; and

sending the determined received power value of the specified forward link channel signal via a specified reverse link common channel message.

33. The method as claimed in claim 32, wherein the specified forward link channel is a pilot channel.

34. A method for determining initial transmission power for a forward link channel signal at a base station in a mobile communications system, comprising steps of:

receiving information indicating a specified reverse link channel signal and the transmission power of the revere link channel signal from a mobile station;

measuring, at the base station, the received power of the specified reverse link channel signal and determining the initial transmission power to be in proportion to a difference between the transmission power of the specified reverse link channel and the measured received power of the specified reverse link channel; and

sending the forward link channel signal with the determined initial transmission power.

35. The method as claimed in claim 34, wherein the specified reverse link channel is a reverse link pilot channel and a channel for receiving the information about the transmission power is an access channel.

36. A method for communication of a channel at a mobile station in a mobile communications system, wherein a base station receives information about a specified channel from the mobile station and determines an initial transmission power for a forward link channel, the method comprising the steps of:

sending a specified reverse link channel signal via a first channel;

sending information about the transmission power of the specified reverse link channel signal via a common channel, wherein the common channel is not the first channel; and

determining a difference between the transmission power of the specified reverse link channel signal and the reception power of the specified reverse link channel signal to determine the initial transmission power for the forward link channel,

wherein the initial transmission power for the forward link channel is determined to be proportional to the difference between the transmission power of the specified reverse link channel signal and the reception power of the specified reverse link channel signal.

37. The method as claimed in claim 36, wherein the specified revere link channel is a reverse link pilot channel and the common channel is an access channel.

38. A device for determining an initial transmission power for a forward link channel signal at a base station in a mobile communications system, comprising:

a pilot channel transmitter for transmitting a pilot channel signal via a pilot channel;

a common channel receiver for receiving information indicating a strength of a specified channel from a mobile station, wherein the specified channel in not the pilot channel;

a transmission power controller for controlling the initial transmission power for the forward link channel signal according to the received information about the strength of the specified channel by determining a difference between the transmission power of the pilot channel signal and the reception power of the specified channel signal; and

a channel transmitter for transmitting the forward link channel signal with the determined initial transmission power,

wherein the initial transmission power for the forward link channel signal is controlled proportional to the difference between the transmission power of the pilot channel signal and the reception power of the specified channel signal.

39. The device as claimed in claim 38, wherein the common channel receiver is an access channel and the channel transmitter is a control channel.

40. The device as claimed in claim 38, wherein the common channel receiver is an access channel and the channel transmitter is a traffic channel.

41. A device for communicating a channel at a mobile station in a mobile communications system, comprising:

a pilot channel receiver for receiving a specified forward link channel signal;

a power measurer for despreading the specified forward link channel signal to measure energy per forward link channel chip, measuring total received power spectral density of all received signals, and determining received power of the specified forward link channel signal according to a ratio of the energy per a specified channel signal chip to the total received power spectral density; and

a common channel transmitter for transmitting the received power of the specified forward link channel signal via a specified forward link common channel message.

42. A device for determining an initial transmission power for a forward link channel signal at a base station in a mobile communications system, the device comprising:

a power measurer for receiving a specified reverse link channel signal from a mobile station and measuring a received power of the specified reverse link channel signal;

a common channel receiver for receiving information indicating a transmission power of the specified reverse link channel signal;

a transmission power controller for determining the initial transmission power to be proportional to a difference between the transmission power and the measured received power of the specified reverse link channel signal; and

a channel transmitter for sending the forward link channel signal with the determined initial transmission power.

43. A device for communicating a channel at a mobile station in a mobile communications system, wherein a base station receives information about a specified channel from the mobile station and determines initial transmission power for a forward link channel, the device comprising:

a reverse link pilot channel transmitter for transmitting a specified reverse link channel signal via a first channel;

an access channel transmitter for transmitting via an access channel transmission power of the specified reverse link channel signal via a message, wherein the access channel is not the first channel; and

a transmission power controller for determining a difference between the transmission power of the specified reverse link channel signal and the reception power of the specified reverse link channel signal to determine the initial transmission power for the forward link channel,

wherein the initial transmission power for the forward link channel is controlled proportional to the difference between the transmission power of the specified reverse link channel signal and the reception power of the specified reverse link channel signal.