802.11 networks using dynamic power control for RF transmission

• US 7,570,929 B1
• Filed: 01/14/2000
• Issued: 08/04/2009
• Est. Priority Date: 01/14/2000
• Status: Expired due to Term

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Symbol Technologies, Inc. (Zebra Technologies Corporation)
• Inventors: Trompower, Michael L.
• Primary Examiner(s): MEHRPOUR, NAGHMEH
• Application Number:
  US09/483,399
• Time in Patent Office: 3,490 Days
• Field of Search: 455/114, 455/91, 455/522, 455/127, 455/575, 455/64, 455/114.3, 455/574, 455/127.1, 455/127.5, 455/13.4, 375/297, 375/296, 375/295, 370/318, 370/319, 370/321, 370/465, 370/337, 370/347, 370/338, 709/229, 709/240
• US Class Current: 455/114.3
• CPC Class Codes: H04W 28/22 Negotiating communication rate
• CPC Class Codes: H04W 52/286 during data packet transmission, e.g. high speed packet access [HSPA]

Abstract

A system and method is provided for adjusting transmission power of different portions of a data packet. The system and method is especially useful when utilizing the IEEE 802.11 standard protocol due to the varying transmission data rates of a packet. A IEEE 802.11 packet includes a preamble portion, a header portion and a data portion. The preamble portion has a data rate of 1 Mbps, the header has a data rate of 1 or 2 Mbps and the data portion has a data rate of 1, 2, 5.5 or 11 Mbps. At a given fixed power level, a transmission at a higher data rate has a lower transmission range than a transmission at a lower data rate. Therefore, the present invention provides for a system and method that adjusts the power level of different portions of a data packet, so that the entire data packet has a more uniform range. This eliminates the need for components in the system receiving a preamble portion of a transmission at higher ranges to remain idle during transmission of an entire frame. The system and method can be applied to both access points and mobile units in a cellular communications system.

Claims

1. A communication unit in a cellular communication system, the unit comprising:

a transmitter that transmits a data packet over an RF link, the data packet includes a first portion that is transmitted at a first data rate and a second portion that is transmitted at a second data rate that is not equal to the first data rate; and

a power control module that receives the data packet and that determines a first transmission power for the first portion and a second transmission power for the second portion such that the first portion and the second portion when transmitted at disparate data rates will achieve a uniform transmission range.

2. The unit of claim 1, the data packet includes a third portion and the power control module determines a third transmission power for the third portion based upon the uniform transmission range.

3. The unit of claim 2, the communication unit transmits the first portion of the data packet at a first data rate, the second portion of the data packet at a second data rate and the third portion of the data packet at a third data rate.

4. The unit of claim 3, the data packet conforms to the IEEE 802.11 standard protocol and the first portion of the data packet is a PLCP preamble, the second portion of the data packet is a PLCP header and the third portion of the data packet is a data portion.

5. The unit of claim 1, the communication unit is an access point system.

6. The unit of claim 1, the communication unit is a mobile communication unit.

7. The unit of claim 1, the power control module includes a transmission power amplifier adapted to receive the data packet and dynamically control the transmission power of the first portion and the second portion.

8. The unit of claim 7, the power control module includes a D/A converter that receives power data information in digital format and that converts the power data information to an analog control signal, the analog signal controls the transmission power of the transmission power amplifier.

9. The unit of claim 8, further including a processor coupled to the D/A converter, the processor transmits the power data information to the D/A converter.

10. The unit of claim 9, further including a receiver coupled to the processor, the receiver receives a transmission from another communication unit.

11. The unit of claim 10, the receiver provides transmission power information to the processor from a transmission communication unit transmitting information to the receiver, the processor evaluates a range from the transmission power information and downloads power data information to the power control circuit based on the uniform transmission range of the data packet.

12. The unit of claim 8, the power control module includes a power data register section coupled to the D/A converter, the power data register module stores the power data information and provides the power data information to the D/A converter.

13. The unit of claim 12, further including a processor coupled to the power data register section, the processor transmits the power data information to the power data register section.

14. The unit of claim 13, further including a receiver coupled to the processor, the receiver receives a transmission from other communication units.

15. The unit of claim 14, the receiver provides transmission power information to the processor from a transmission communication unit transmitting information to the receiver, the processor evaluates a range from the transmission power information and downloads power data information to the power control circuit based on the uniform transmission range of the data packet.

16. The unit of claim 1, the communication unit is coupled to a network and the network provides the power control circuit with information relating to the power transmission level of the first portion and the second portion.

17. A method of transmitting a data packet in a cellular communication system, comprising:

transmitting a first portion of the data packet at a first transmission power level;

transmitting a second portion of the data packet at a second transmission power level; and

transmitting a third portion of the data packet at a third transmission power level.

18. The method of claim 17, the first portion of the data packet is transmitted at a first data rate and the second portion of the data packet is transmitted at a second data rate.

19. The method of claim 17, the first power level and the second power level are adjusted so that the first portion and the second portion have essentially the same transmission range.

20. The method of claim 17, further comprising providing a communication unit prior to transmitting a first portion of the data packet at a first transmission power level, the communication unit including a transmitter, a power control module coupled to the transmitter, a processor coupled to the power control module and a receiver coupled to the processor.

21. The method of claim 20, the processor provides the power control module with the first transmission power and the second transmission power after providing a communication unit and prior to transmitting a first portion of the data packet at a first transmission power level.

22. The method of claim 21, the processor evaluates the first transmission power and the second transmission power based on a desired transmission range for the first portion and the second portion of the data packet.

23. The method of claim 22, the processor evaluates the first transmission power and the second transmission power based on a desired transmission range for the first portion and the second portion of the data packet based on a transmission power level of a transmission received from another mobile communication unit.

24. The method of claim 22, the communication unit is coupled to a network and the processor evaluates the first transmission power and the second transmission power based on a desired transmission range for the first portion and the second portion of the data packet, the network providing the processor information relating to the desired transmission range.

25. The method of claim 17, the power level of the first portion and the second portion is dynamically adjusted during the transmission of the data packet.

26. An access point system in a cellular communication system utilizing an IEEE 802.11 standard protocol, comprising:

a transmitter that transmits data over an RF link;

a power control module coupled to the transmitter, the power control module receives a data packet having a PLCP preamble and PLCP header portion and a data portion and dynamically adjusts the transmission power of the packet during transmission of the packet, such that the PLCP preamble portion begins transmitting at a first transmission power level and the data portion begins transmitting at a second transmission power level, the dynamic adjustment of transmission power made to facilitate transmitting the PLCP preamble and the data portion over a substantially similar transmission range;

a processor coupled to the power adjustment module, the processor provides power adjustment information to the power control module; and

a receiver coupled to the processor, the receiver receives data over an RF link, the access point system is coupled to a network.

27. The system of claim 26, the power control module includes a transmission power amplifier that receives the data packet and control the transmission power of the PLCP preamble portion and the data portion, the transmission power amplifier coupled to a D/A converter, the D/A converter receives power data information in digital format and converts the power data information to an analog control signal, the analog control signal controls the transmission power of the transmission power amplifier.

28. The system of claim 27, the power control module includes a power data register module coupled to the D/A converter, the power data register stores the power data information and provides the power data information to the D/A converter, the processor is coupled to the D/A converter, the processor transmits the power data information to the D/A converter.

29. A cellular communication system, comprising:

means for transmitting a data packet having a first portion and a second portion;

means for dynamically adjusting a transmission power level of the first portion with respect to the second portion of the data packet coupled to the means for transmitting a data packet having a first portion and a second portion; and

means for determining the transmission power level of the first and second portion, whereby each portion is to be transmitted at a disparate data rate, the transmission power level is determined in order to match a desired transmission range.

30. The system of claim 29, the means for dynamically adjusting the transmission power level of the first portion with respect to the second portion of the data packet further provides for adjusting the power transmission level of a third portion of the data packet with respect to the first and second portions, in order to match the desired transmission range.

31. A signal transmitted over a wireless communication system, the signal comprising:

a data packet having a first portion transmitted at a first power level, a second portion transmitted at a second power level, and a third portion transmitted at a third power level.