Apparatus and method for controlling transmit power of preamble sequence for AAS in OFDMA communication system

• US 20060092875A1
• Filed: 10/31/2005
• Published: 05/04/2006
• Est. Priority Date: 10/29/2004
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kwon, Young-Hoon, Yang, Jang-Hoon, Hwang, In-Seok
• Granted Patent: US 7,826,417 B2
• Time in Patent Office: Days
• US Class Current: 370/329
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/16 Deriving transmission power values from another channel
• CPC Class Codes: H04W 52/285 taking into account the mobility of the user
• CPC Class Codes: H04W 52/286 during data packet transmission, e.g. high speed packet access [HSPA]
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A method for controlling transmit power of a preamble sequence by a Subscriber Station in an Orthogonal Frequency Division Multiple Access communication system, the system dividing an entire frequency band into a plurality of sub-carrier bands, transmitting an preamble sequence for an Adaptive Antenna System through a predetermined number of sub-carrier bands from among the sub-carrier bands, transmitting a data symbol through remaining sub-carrier bands excluding the sub-carrier bands used for transmitting the preamble sequence. The method includes determining the transmit power used for transmitting the data symbol; and determining the transmit power used for transmitting the preamble sequence to be identical to a preset threshold transmit power when the transmit power of the data symbol is smaller than the threshold transmit power, and determining the transmit power used for transmitting the preamble sequence to be identical to the transmit power of the data symbol when the transmit power of the data symbol exceeds the threshold transmit power.

Claims

1. A method for controlling transmit power of a preamble sequence by a Subscriber Station (SS) in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system, the OFDMA communication system dividing an entire frequency band into a plurality of sub-carrier bands, transmitting an preamble sequence for an Adaptive Antenna System (AAS) through a predetermined number of sub-carrier bands from among the sub-carrier bands, transmitting a data symbol through remaining sub-carrier bands excluding the sub-carrier bands used for transmitting the preamble sequence, the method comprising:

determining the transmit power used for transmitting the data symbol; and

determining the transmit power used for transmitting the preamble sequence to be identical to the transmit power of the data symbol.

2. The method as claimed in claim 1, wherein the transmit power used for transmitting the data symbol is determined by selecting one of an open loop power control mode, a closed loop power control mode and an outer loop power control mode.

3. The method as claimed in claim 2, further comprising:

transmitting a power control mode request to a Base Station (BS) when the SS detects that a selected power control mode must be changed while determining the transmit power used for transmitting the data symbol by means of the selected power control mode of the open loop power control mode and the closed loop power control mode.

4. The method as claimed in claim 3, wherein, when a power control mode to be set later is different from a currently set power control mode, the SS detects that the selected power control mode must be changed, the power control mode to be set later and the currently set power control mode being determined according to a comparison result of a mobility index of the SS and a preset mobility index.

5. The method as claimed in claim 4, further comprising:

changing the power control mode into the power control mode to be set at a later time, when a power control mode change command responding to transmission of the power control mode request is received by the SS from the BS after the power control mode request is transmitted to the BS.

6. The method as claimed in claim 1, wherein the transmit power used for transmitting the data symbol is determined by considering a modulation scheme and a coding rate, which are applied to the data symbol, according to preset reference transmit power.

7. An apparatus for controlling the transmit power of a preamble sequence by a Subscriber Station (SS) in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system, the OFDMA communication system dividing an entire frequency band into a plurality of sub-carrier bands, transmitting an preamble sequence for an Adaptive Antenna System (AAS) through a predetermined number of sub-carrier bands from among the sub-carrier bands, transmitting a data symbol through remaining sub-carrier bands excluding the sub-carrier bands used for transmitting the preamble sequence, the apparatus comprising:

a transmit power controller for determining transmit power used for transmitting the data symbol, and determining the transmit power used for transmitting the preamble sequence to be identical to the transmit power of the data symbol; and

a mobility estimator for detecting a mobility index of the SS.

8. The apparatus as claimed in claim 7, wherein the transmit power controller determines the transmit power used for transmitting the data symbol by selecting one of an open loop power control mode, a closed loop power control mode and an outer loop power control mode.

9. The apparatus as claimed in claim 8, wherein the transmit power controller transmits a power control mode request to a Base Station (BS) when the SS detects that a selected power control mode must be changed while determining the transmit power used for transmitting the data symbol by means of the selected power control mode of the open loop power control mode and the closed loop power control mode.

10. The apparatus as claimed in claim 9, wherein the transmit power controller detects that the selected power control mode must be changed, when a power control mode to be set at a later time is different from a currently set power control mode, the power control mode to be set later and the currently set power control mode being determined according to a comparison result of a mobility index of the SS and a preset mobility index.

11. The apparatus as claimed in claim 10, wherein the transmission power controller changes the power control mode into the power control mode to be set at the later time, when a power control mode change command responding to a transmission of a power control mode request is received by the SS from the BS after the power control mode request is transmitted to the BS.

12. The apparatus as claimed in claim 7, wherein the transmit power controller determines the transmit power used for transmitting the data symbol in consideration of a modulation scheme and a coding rate, which are applied to the data symbol, according to a preset reference transmit power.

13. A method for controlling transmit power of a preamble sequence by a Subscriber Station (SS) in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system, the OFDMA communication system dividing an entire frequency band into a plurality of sub-carrier bands, transmitting an preamble sequence for an Adaptive Antenna System (AAS) through a predetermined number of sub-carrier bands from among the sub-carrier bands, transmitting a data symbol through remaining sub-carrier bands excluding the sub-carrier bands used for transmitting the preamble sequence, the method comprising:

determining the transmit power used for transmitting the preamble sequence to be identical to a preset threshold transmit power.

14. The method as claimed in claim 13, further comprising:

determining the transmit power used for transmitting the data symbol after determining the transmit power used for transmitting the preamble sequence.

15. The method as claimed in claim 14, wherein the transmit power used for transmitting the data symbol is determined by selecting one of an open loop power control mode, a closed loop power control mode and an outer loop power control mode.

16. The method as claimed in claim 15, further comprising:

transmitting a power control mode request to a Base Station (BS) when the SS detects that a selected power control mode must be changed while determining the transmit power used for transmitting the data symbol by means of the selected power control mode of the open loop power control mode and the closed loop power control mode.

17. The method as claimed in claim 16, wherein, when a power control mode to be set at a later time is different from a currently set power control mode, the SS detects that the selected power control mode must be changed, the power control mode to be set later and the currently set power control mode being determined according to a comparison result of a mobility index of the SS and a preset mobility index.

18. The method as claimed in claim 17, further comprising a step of changing the power control mode into the power control mode to be set at the later time, when a power control mode change command responding to transmission of the power control mode request is received by the SS from the BS after the power control mode request is transmitted to the BS.

19. The method as claimed in claim 14, wherein the transmit power used for transmitting the data symbol is determined by considering a modulation scheme and a coding rate, which are applied to the data symbol, according to a preset reference transmit power.

20. An apparatus for controlling transmit power of a preamble sequence by a Subscriber Station (SS) in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system, the OFDMA communication system dividing an entire frequency band into a plurality of sub-carrier bands, transmitting an preamble sequence for an Adaptive Antenna System (AAS) through a predetermined number of sub-carrier bands from among the sub-carrier bands, transmitting a data symbol through remaining sub-carrier bands excluding the sub-carrier bands used for transmitting the preamble sequence, the apparatus comprising

a transmit power controller for determining the transmit power used for transmitting the preamble sequence to be identical to a preset threshold transmit power.

21. The apparatus as claimed in claim 20, wherein the transmit power controller determines transmit power used for transmitting the data symbol

22. The apparatus as claimed in claim 21, further comprising a mobility estimator for detecting a mobility index of the SS.

23. The apparatus as claimed in claim 22, wherein the transmit power controller determines the transmit power used for transmitting the data symbol by selecting one of an open loop power control mode, a closed loop power control mode and an outer loop power control mode.

24. The apparatus as claimed in claim 23, wherein the transmit power controller transmits a power control mode request to a Base Station (BS) when the SS detects that a selected power control mode must be changed while determining the transmit power used for transmitting the data symbol by means of the selected power control mode of the open loop power control mode and the closed loop power control mode.

25. The apparatus as claimed in claim 24, wherein the transmit power controller detects that the selected power control mode must be changed, when a power control mode to be set at a later time is different from a currently set power control mode, the power control mode to be set later and the currently set power control mode being determined according to a comparison result of a mobility index of the SS and a preset mobility index.

26. The apparatus as claimed in claim 25, wherein the transmission power controller changes the power control mode into the power control mode to be set at the later time, when a power control mode change command responding to transmission of the power control mode request is received by the SS from the BS after the power control mode request is transmitted to the BS.

27. The apparatus as claimed in claim 21, wherein the transmit power controller determines the transmit power used for transmitting the data symbol in consideration of a modulation scheme and a coding rate, which are applied to the data symbol, according to a preset reference transmit power.

28. A method for controlling transmit power of a preamble sequence by a Subscriber Station (SS) in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system, the OFDMA communication system dividing an entire frequency band into a plurality of sub-carrier bands, transmitting an preamble sequence for an Adaptive Antenna System (AAS) through a predetermined number of sub-carrier bands from among the sub-carrier bands, transmitting a data symbol through remaining sub-carrier bands excluding the sub-carrier bands used for transmitting the preamble sequence, the method comprising:

determining the transmit power used for transmitting the data symbol; and

determining the transmit power used for transmitting the preamble sequence to be identical to a preset threshold transmit power when the transmit power of the data symbol is smaller than the threshold transmit power, and determining the transmit power used for transmitting the preamble sequence to be identical to the transmit power of the data symbol when the transmit power of the data symbol exceeds the threshold transmit power.

29. The method as claimed in claim 28, wherein the transmit power used for transmitting the data symbol is determined by selecting one of an open loop power control mode, a closed loop power control mode and an outer loop power control mode.

30. The method as claimed in claim 29, further comprising:

transmitting a power control mode request to a Base Station (BS) when the SS detects that a selected power control mode must be changed while determining the transmit power used for transmitting the data symbol by means of the selected power control mode of the open loop power control mode and the closed loop power control mode.

31. The method as claimed in claim 30, wherein, when a power control mode to be set at a later time is different from a currently set power control mode, the MS detects that the selected power control mode must be changed, the power control mode to be set later and the currently set power control mode being determined according to a comparison result of a mobility index of the SS and a preset mobility index.

32. The method as claimed in claim 31, further comprising:

changing the power control mode into the power control mode to be set at the later time, when a power control mode change command responding to transmission of the power control mode request is received by the SS from the BS after the power control mode request is transmitted to the BS.

33. The method as claimed in claim 28, wherein the transmit power used for transmitting the data symbol is determined by considering a modulation scheme and a coding rate, which are applied to the data symbol, according to a preset reference transmit power.

34. An apparatus for controlling transmit power of a preamble sequence by a Subscriber Station (SS) in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system, the OFDMA communication system dividing an entire frequency band into a plurality of sub-carrier bands, transmitting an preamble sequence for an Adaptive Antenna System (AAS) through a predetermined number of sub-carrier bands from among the sub-carrier bands, transmitting a data symbol through remaining sub-carrier bands excluding the sub-carrier bands used for transmitting the preamble sequence, the apparatus comprising:

a transmit power controller for determining the transmit power used for transmitting the data symbol, determining the transmit power used for transmitting the preamble sequence to be identical to a preset threshold transmit power when the transmit power of the data symbol is smaller than the threshold transmit power, and determining the transmit power used for transmitting the preamble sequence to be identical to the transmit power of the data symbol when the transmit power of the data symbol exceeds the threshold transmit power; and

a mobility estimator for detecting a mobility index of the MS.

35. The apparatus as claimed in claim 34, wherein the transmit power controller determines the transmit power used for transmitting the data symbol by selecting one of an open loop power control mode, a closed loop power control mode and an outer loop power control mode.

36. The apparatus as claimed in claim 35, wherein the transmit power controller transmits a power control mode request to a Base Station (BS) when the SS detects that a selected power control mode must be changed while determining the transmit power used for transmitting the data symbol by means of the selected power control mode of the open loop power control mode and the closed loop power control mode.

37. The apparatus as claimed in claim 36, wherein the transmit power controller detects that the selected power control mode must be changed, when a power control mode to be set at a later time is different from a currently set power control mode, the power control mode to be set later and the currently set power control mode being determined according to a comparison result of a mobility index of the SS and a preset mobility index.

38. The apparatus as claimed in claim 37, wherein the transmit power controller changes the power control mode into the power control mode to be set at a later time, when a power control mode change command responding to transmission of the power control mode request is received by the SS from the BS after the power control mode request is transmitted to the BS.

39. The apparatus as claimed in claim 34, wherein the transmit power controller determines the transmit power used for transmitting the data symbol in consideration of a modulation scheme and a coding rate, which are applied to the data symbol, according to a preset reference transmit power.