Forward direction power control method using backward direction power control sub-channel for mobile communication system

• US 6,781,966 B1
• Filed: 08/22/2000
• Issued: 08/24/2004
• Est. Priority Date: 08/31/1999
• Status: Expired due to Fees

• Current Assignee: Utstarcom Korea Limited
• Original Assignee: Hyundai Electronics Industries Co. Ltd. (SK Hynix Inc.)
• Inventors: Kim, Jin Sook
• Primary Examiner(s): HSU, ALPUS
• Application Number:
  US09/643,496
• Time in Patent Office: 1,463 Days
• Field of Search: 370/311, 370/328, 370/329, 370/331, 370/332, 370/335, 370/342, 375/130, 375/140, 375/141, 455/38.3, 455/67.1, 455/68, 455/69, 455/422, 455/436, 455/507, 455/509, 455/517, 455/522, 455/13.4
• US Class Current: 370/311
• CPC Class Codes: H04W 52/08 Closed loop power control
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/20 using error rate

Abstract

In the present invention, a forward direction power control method using a backward direction power control sub-channel for a mobile communication system is disclosed. The method according to the present invention is directed to rapidly and effectively controlling the power of a base station transmission signal using a power control, sub-channel in a backward direction pilot channel when performing an outer loop and inner loop in a mobile station of a mobile communication system which adapts an IS-2000 CDMA method and rapidly coping with a channel environment and forward direction wireless environment for thereby decreasing the power of a transmission signal of the base station and increasing the capacity of the system.

Claims

1. A forward direction power control method using a backward direction power control sub-channel for a mobile communication system, comprising the steps of:

a channel information and channel transmission and receiving step for transmitting and receiving a channel information for performing an inner loop and a channel corresponding to the channel information for a forward direction power control between a mobile station and a base station;

a channel-based receiving power measuring step for measuring a channel-based current receiving power when a mobile station receives a channel in the channel information and channel transmission and receiving step;

an outer loop operation step for determining a channel-based reference receiving power that the mobile station receives as the mobile station performs an outer loop at a period of 20 ms after the channel-based receiving power measuring step;

an inner loop operation step for performing an inner loop at a period of 1.25 ms by the mobile station after the outer loop operation step and comparing the current channel-based receiving power measured in the channel-based receiving power measuring step and the channel-based reference receiving power determined in the outer loop operation and determining an information for requesting a power up or down of the base station transmission signal and allocating the determined information to a power control bit (PCB) of the backward direction power control sub-channel;

a backward direction power control sub-channel transmission and receiving and power control step for transmitting and receiving a backward direction power control sub-channel including the PCB having an information allocated in the inner loop operation between the mobile station and the base station and controlling the power of the base station transmission signal in accordance with the information allocated to the PCB of the backward direction power control sub-channel;

an outer loop report message transmission state determination step in which the mobile station is determined to transmit the outer loop report message to the base station after the backward direction power control sub-channel transmission and receiving and power control step;

an outer loop report message transmission and power control step for transmitting and receiving an outer loop report message between the mobile station and the base station in the case that the result determined in the outer loop report message transmission state determination step corresponds to the outer loop report message transmission permission and performing the power control of the base station transmission signal with respect to the base station transmission signal; and

an outer loop report message non-transmission step for performing the channel information and channel transmission and receiving step in a state that the mobile station does not transmit the outer loop report message to the base station in the case that the result determined in the outer loop report message transmission state determination step does not correspond to the outer loop report message transmission permission and performing the next steps.

2. The method of claim 1, wherein said outer loop operation step includes the steps of:

a channel-based receiving frame state check and frame error ratio computation step in which the mobile station checks the state of each channel-based receiving frame for computing the current channel-based frame error ratio in accordance with the state of the checked channel-based receiving frame;

a frame error ratio comparison step for judging whether the current channel-based frame error ratio computed in the channel-based receiving frame state check and frame error ratio computation step is below a channel-based reference frame error ratio;

a channel-based reference receiving power down step for determining the channel-based reference receiving power by decreasing the channel-based reference receiving power when the current channel-based frame error ratio is below the channel-based reference frame error ratio as a result of the frame error ratio comparison step; and

a channel-based reference receiving power up step for determining the channel-based reference receiving power by increasing the channel-based reference receiving power when the current channel-based frame error ratio exceeds the channel-based reference frame error ratio as a result of the comparison of the frame error ratio comparison step.

3. The method of claim 1, wherein said inner loop operation step includes:

a channel-based receiving power check step in which the mobile station checks the current channel-based receiving power;

a channel-based receiving power comparison step for judging whether the current channel-based receiving power checked in the channel-based receiving power check step is below the channel-based reference receiving power determined in the channel-based reference receiving power down or up step of the outer loop operation step;

an information determination and PCB allocation step for determining an information for requesting a power up of the base station transmission signal when the current channel-based receiving power is below the channel-based reference receiving power as a result of the channel-based receiving power comparison step and allocating the determined information to the backward direction power control sub-channel; and

an information determination and PCB allocation step for determining an information for requesting a power down of the base station transmission signal when the current channel-based receiving power exceeds the channel-based reference receiving power as a result of the channel-based receiving power comparison step and decreasing the power of the base station transmission signal for allocating the determined information to the PCB of the backward direction power control sub-channel.

4. The method of claim 3, wherein in the information determination and PCB allocation step for a power up of the base station transmission signal, the information for requesting a power up of the base station transmission signal is “

1”

.

5. The method of claim 3, wherein in the information determination and PCB allocation step for a power up of the base station transmission signal, the information for requesting a power down of the base station transmission signal is “

0”

.

6. The method of claim 1, wherein said backward direction power control sub-channel transmission and receiving and power control step includes the steps of:

a backward direction power control sub-channel receiving step for receiving the backward direction power control sub-channel including the PCB having an information allocated in the information determination and PCB allocation step from the mobile station for increasing or decreasing the power of the base station transmission signal of the inner loop operation step in the base station;

a backward direction power control sub-channel information verification step for verifying an information allocated to the PCB of the backward direction power control sub-channel received in the backward direction power control sub-channel receiving step;

a base station transmission signal power down control step for decreasing the power of the base station transmission signal in the case that the information allocated to the PCB of the backward direction power control sub-channel is “

0”

as a result of the backward direction power control sub-channel information verification step; and

a base station transmission signal power up control step for increasing the power of the base station transmission signal in the case that the information allocated to the PCB of the backward direction power control sub-channel is “

1”

as a result of the backward direction power control sub-channel information verification step.

7. The method of claim 6, wherein in the backward direction power control sub-channel receiving step, in the case that the information of “

0”

or “

1”

allocated to the PCB of the backward direction power control sub-channel continuously exceeds a certain threshold value, the power up value of the base station transmission signal is increased, and the power of the base station transmission signal is controlled, and in the case that the information does not continuously exceed the threshold value, the power up and down value of the vase station transmission signal is decreased for thereby controlling the power of the base station transmission signal.

8. The method of claim 1, wherein said outer loop report message transmission state determination step includes the steps of:

an inner loop non-performed channel existing check and receiving power difference measuring step in which the mobile station judges whether there is an inner loop non-performed channel for measuring the difference between the current receiving power of the inner loop non-performed channel and the current receiving power of the inner loop performed channel in the case that there is a loop non-performed channel as a result of the judgement;

a threshold value comparison step for judging whether the difference measured in the inner loop non-performed channel existing check and receiving power difference measuring step exceeds the threshold value;

an outer loop report message transmission determination step for transmitting an outer loop report message to the base station when the measured difference exceeds the threshold value as a result of the comparison of the threshold value comparison step; and

an outer loop report non-transmission determination step in which the outer loop report message is not transmitted to the base station when the measured difference is below the threshold value as a result of the threshold value comparison step.

9. The method of claim 1, wherein said outer loop report message transmission and receiving and power control step includes:

a receiving power comparison step in which the base station receives an outer loop report message from the mobile station, and it is judged whether the current receiving power of the inner loop non-performed channel is below the current receiving power of the inner loop performing channel based on the information of the received outer loop report message;

a base station transmission signal power up step for increasing the power of the base station transmission signal with respect to the inner loop non-performed channel when the current receiving power of the inner loop non-performed channel is below the current receiving power of the inner loop performing channel as a result of the receiving power comparison step; and

a base station transmission signal power down step for decreasing the power of the base station transmission signal with respect to the inner loop non-performed channel when the current receiving power of the inner loop non-performed channel exceeds the current receiving power of the inner loop performing channel as a result of the receiving power comparison step.