Wireless communication device capable of controlling transmission power and transmission power control method therefor and wireless communication system employing the same

• US 20010011023A1
• Filed: 01/30/2001
• Published: 08/02/2001
• Est. Priority Date: 01/31/2000
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Ohnishi, Hidetomo, Nishioka, Ryousuke
• Granted Patent: US 6,871,078 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets
• CPC Class Codes: H04W 52/50 at the moment of starting communication in a multiple access environment

Abstract

The present invention provides a method of controlling transmission power including the steps of: increasing transmission power immediately after a data transmission without waiting for a response signal to be received indicating a result of receiving the transmitted data; if the response signal received reveals that the transmitted data has been unsuccessfully received, retransmitting the same data and also holding transmission power applied when the data is retransmitted; if the response signal received reveals that the transmitted data has been successfully received and data previously transmitted has also been successfully received, reducing transmission power for a subsequent data transmission by a predetermined amount; and if the response signal received reveals that the data transmitted has been successfully received and data previously transmitted has been unsuccessfully received, setting transmission power for the subsequent data transmission depending on the transmission power held being applied when the data was retransmitted.

Claims

1. A wireless communication device comprising:

a control portion for setting data to be transmitted subjected to data transmission, and a level of transmission power for said data transmission;

a transmitter for performing said data transmission with the level of transmission power set by said control portion; and

a response signal determination portion for determining from an externally received signal whether said data transmission provides a successful transmission result or an unsuccessful transmission result,

wherein said control portion

i) after said data transmission has completed and before said transmission result is determined, increases a level of transmission power for a current data transmission by a first predetermined level to a first level of power to set a level of transmission power for a subsequent data transmission, and

ii) if said response signal determination portion determines that said data transmission provides said successful transmission result, sets the level of transmission power for said subsequent data transmission to have a second level of power corresponding to said first level of power minus a second predetermined level.

2. The wireless communication device of

claim 1

, wherein if said response signal determination portion determines that said data transmission provides an unsuccessful transmission result then said control portion subjects data to be transmitted identical to that with said unsuccessful transmission result to said subsequent data transmission and said transmitter in said subsequent data transmission uses said first level of power to retransmit data to be transmitted identical to that with said unsuccessful transmission result.

3. The wireless communication device of

claim 2

, further comprising a memory for storing as a lower limit level of transmission power the level of transmission power of said retransmission when said data transmission is determined to provide said unsuccessful transmission result, wherein if said data transmission is determined to provide said successful transmission result said control portion refers to whether said memory stores said lower limit level of transmission power, to set the level of transmission power for said subsequent data transmission to be either one of said lower limit level of transmission power and said second level of power.

4. The wireless communication device of

claim 3

, further comprising a timer detecting whether a predetermined period has elapsed, wherein whenever said timer detects that said predetermined period has elapsed said control portion clears said lower limit level of transmission power held in said memory.

5. The wireless communication device of

claim 3

, wherein if said data transmission is determined to provide said unsuccessful transmission result and said lower limit level of transmission power has already been held then said control portion initializes said lower limit level of transmission power and increases the level of transmission power for said subsequent data transmission up to a predetermined level of power.

6. The wireless communication device of

claim 5

, wherein said predetermined level of power is a maximal value in a controllable range of the level of transmission power in said wireless communication device.

7. The wireless communication device of

claim 2

, wherein:

said second predetermined level is greater than said first predetermined level; and

if said response signal determination portion determines that said data transmission provides said successful transmission result, then said control portion provides, in parallel, setting data to be transmitted subjected to said subsequent data transmission and setting the level of transmission power for said subsequent data transmission to be said second level of power.

8. The wireless communication device of

claim 2

, wherein:

said second predetermined level is greater than said first predetermined level; and

if said response signal determination portion determines that said data transmission provides said successful transmission result, then said control portion provides, in series, setting data to be transmitted subjected to said subsequent data transmission and setting the level of transmission power for said subsequent data transmission to be said second level of power.

9. The wireless communication device of

claim 1

, wherein said second predetermined level is greater than said first predetermined level.

10. A method of controlling transmission power of a wireless communication device capable of controlling a level of transmission power, comprising the steps of:

performing data transmission with the level of transmission power;

after said data transmission has completed, increasing the level of transmission power in said data transmission by a first predetermined level to provide a level of transmission power for a subsequent data transmission;

determining from an externally received signal whether said data transmission provides a successful transmission result or an unsuccessful transmission result; and

if said data transmission provides said successful transmission result, decreasing by a second predetermined level the level of transmission power for said subsequent data transmission corresponding to the level of transmission power increased by said first predetermined level.

11. The method of

claim 10

, further comprising the step of retransmitting data identical to that transmitted in said data transmission determined to provide said unsuccessful transmission result, with the level of transmission power increased by said first predetermined level.

12. The method of

claim 11

, further comprising the steps of:

if said data transmission is determined to provide said unsuccessful transmission result, holding as a lower limit level of transmission power a level of transmission power being applied when said unsuccessful transmission result is detected; and

if said data transmission is determined to provide said successful transmission result and said lower limit level of transmission power has already been held, setting the level of transmission power for said subsequent data transmission to be said lower limit level of transmission power, rather than the step of decreasing.

13. The method of

claim 12

, further comprising the steps of:

determining whether a predetermined period has elapsed; and

whenever said predetermined period elapses, initializing said lower limit level of transmission power held.

14. The method of

claim 12

, further comprising the step of initializing said lower limit level of transmission power, if any held, and increasing the level of transmission power for said subsequent data transmission up to a predetermined level of power, if said data transmission is determined to provide said unsuccessful transmission result.

15. The method of

claim 12

, wherein said predetermined level of power is a maximal value in a controllable range of the level of transmission power in said wireless communication device.

16. The method of

claim 11

, said second predetermined level being greater than said first predetermined level, further comprising the step of processing data subjected to said subsequent data transmission, if said data transmission is determined to provide said successful transmission result, the step of processing being provided in parallel with the step of decreasing.

17. The method of

claim 11

, said second predetermined level being greater than said first predetermined level, further comprising the step of processing data subjected to said subsequent data transmission, if said data transmission is determined to provide said successful transmission result, the step of processing being provided in series with the step of decreasing.

18. The method of

claim 10

, wherein said second predetermined level is greater than said first predetermined level.

19. A wireless communication system comprising:

a receiving, first wireless communication device returning a response signal indicative of a result of receiving transmitted data;

a transmitting, second wireless communication device capable of controlling a level of transmission power in data transmission, said second wireless communication device including

a control portion for setting data to be transmitted subjected to said data transmission and a level of transmission power for said data transmission,

a transmitter for performing said data transmission with the level of transmission power set by said control portion, and

a response signal determination portion determining from said response signal whether said data transmission provides a successful transmission result or an unsuccessful transmission result, said control portion

i) after said data transmission completes and before said transmission result is determined, increasing a level of transmission power for a current data transmission by a first predetermined level to a first level of power to provide a level of transmission power for a subsequent data transmission, and

ii) if said response signal determination portion determines that said data transmission provides said successful transmission result, setting the level of transmission power for the subsequent data transmission to be a second level of power corresponding to said first level of power minus a second predetermined level.

20. The wireless communication system of

claim 19

, wherein if said response signal determination portion determines that said data transmission provides said unsuccessful transmission result then said control portion subjects data to be transmitted identical to that with said unsuccessful transmission result to said subsequent data transmission and said transmitter in said subsequent data transmission uses said first level of power to retransmit data to be transmitted identical to that with said unsuccessful transmission result.