Multi-carrier transmission apparatus, multi-carrier reception apparatus, and multi-carrier radio communication method

• US 20040009783A1
• Filed: 03/12/2003
• Published: 01/15/2004
• Est. Priority Date: 07/13/2001
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Miyoshi, Kenichi
• Granted Patent: US 7,200,177 B2
• Time in Patent Office: Days
• US Class Current: 455/522
• CPC Class Codes: H04B 1/692 Hybrid techniques using combinations of two or more spread spectrum techniques
• CPC Class Codes: H04L 1/0025 Transmission of mode-switching indication
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 1/0032 Without explicit signalling
• CPC Class Codes: H04L 1/0034 where the transmitter decides based on inferences, e.g. use of implicit signalling
• CPC Class Codes: H04W 52/346 distributing total power among users or channels
• CPC Class Codes: H04W 52/42 in systems with time, space, frequency or polarisation diversity

Abstract

A subcarrier transmission ON/OFF control system based on an MC-CDMA system capable of improving information transmission efficiency and reception performance while keeping the number of transmission bits constant. Furthermore, a subcarrier transmit power control system based on an MC-CDMA system or OFDM system capable of improving information transmission efficiency and reception performance. The former system based on the MC-CDMA system does not carry out transmission through subcarriers of low reception quality, with no transmit power assigned (transmission OFF), assigns the corresponding transmit power to subcarriers with transmit power assigned (transmission ON) and carries out transmission (subcarrier transmission ON/OFF control) The latter system based on the MC-CDMA system or OFDM system carries out transmission according to a reception level of each subcarrier on the receiving side, with greater transmit power assigned to subcarriers with higher reception levels and smaller transmit power assigned to subcarriers with lower reception levels (subcarrier reverse transmit power control).

Claims

1. A multicarrier transmission apparatus that carries out radio communication by spreading signals in a frequency axis direction, comprising:

an acquisition section that acquires assignment presence/absence information on whether transmit power is assigned to each subcarrier or not; and

an assignment section that assigns transmit power for subcarriers with no transmit power assigned, to subcarriers with transmit power assigned, based on the assignment presence/absence information acquired by said acquisition section.

2. A multicarrier transmission apparatus according to claim 1, wherein said acquisition section performs said assignment so that the total data transmit power is kept constant.

3. A multicarrier transmission apparatus according to claim 1, wherein subcarriers with no transmit power assigned are a preset number (P) of subcarriers of relatively low reception quality for each symbol among subcarriers to which signals of chips corresponding in number (N) to a predetermined spreading factor (N) are respectively assigned obtained by spreading each symbol with said predetermined spreading factor in the frequency axis direction and the subcarriers with transmit power assigned are transmitted with transmit power multiplied by N/(N−

P) times.

4. A multicarrier transmission apparatus according to claim 3, wherein the number (P) per one symbol of subcarriers with no transmit power assigned is adaptively changeable.

5. A multicarrier transmission apparatus according to claim 3, wherein the number (P) per one symbol of subcarriers with no transmit power assigned is set to a value that satisfies the following expression:

2<sup>(N−

P−

1)</sup>≧

N

6. A multicarrier transmission apparatus according to claim 1, wherein said acquisition section comprising:

a reception section that receives reception quality information on the reception quality of each subcarrier estimated on the receiving side; and

a decision section that decides said assignment presence/absence information based on the reception quality information received by said reception section.

7. A multicarrier transmission apparatus according to claim 1, wherein said acquisition section comprises a reception section that receives said assignment presence/absence information decided on the receiving side.

8. A multicarrier transmission apparatus according to claim 1, wherein said acquisition section comprising:

a first estimation section that estimates a delay profile of a received signal;

a second estimation section that estimates the reception quality information on the reception quality of each subcarrier using the delay profile estimated by said first estimation section; and

a decision section that decides said assignment presence/absence information based on the reception quality information estimated by said second estimation section.

9. A multicarrier reception apparatus that carries out radio communication with the multicarrier transmission apparatus according to claim 6, comprising:

an estimation section that estimates reception quality information on the reception quality of each subcarrier; and

a transmission section that transmits the reception quality information estimated by said estimation section.

10. A multicarrier reception apparatus that carries out radio communication with a multicarrier transmission apparatus according to claim 7, comprising:

an estimation section that estimates reception quality information on the reception quality of each subcarrier;

a decision section that decides assignment presence/absence information on whether transmit power is assigned to each subcarrier or not based on the reception quality information estimated by said estimation section; and

a transmission section that transmits the assignment presence/absence information decided by said decision section.

11. A base station apparatus comprising a multicarrier transmission apparatus according to claim 1.

12. A mobile station apparatus comprising a multicarrier reception apparatus according to claim 9.

13. A mobile station apparatus comprising a multicarrier reception apparatus according to claim 10.

14. A mobile station apparatus comprising a multicarrier transmission apparatus according to claim 1.

15. A base station apparatus comprising a multicarrier reception apparatus according to claim 9.

16. A base station apparatus comprising a multicarrier reception apparatus according to claim 10.

17. A multicarrier radio communication method for a multicarrier transmission apparatus that carries out radio communication by spreading signals in a frequency axis direction, comprising:

an acquisition step of acquiring assignment presence/absence information on whether transmit power is assigned to each subcarrier or not; and

an assignment step of assigning transmit power for subcarriers with no transmit power assigned, to subcarriers with transmit power assigned, based on the assignment presence/absence information acquired in said acquisition step.

18. A multicarrier radio communication method according to claim 17, wherein in said acquisition step, said assignment is carried out so that the total data transmit power is kept constant.

19. A multicarrier radio communication method according to claim 17, wherein subcarriers with no transmit power assigned are a preset number (P) of subcarriers of relatively low reception quality for each symbol among subcarriers to which signals of chips corresponding in number (N) to a predetermined spreading factor (N) are respectively assigned obtained by spreading each symbol with said predetermined spreading factor in the frequency axis direction and the subcarriers with transmit power assigned are transmitted with transmit power multiplied by N/(N−

P) times.

20. A multicarrier radio communication method according to claim 19, wherein the number (P) of subcarriers with no transmit power assigned per one symbol is adaptively changeable.

21. A multicarrier radio communication method according to claim 19, wherein the number (P) of subcarriers with no transmit power assigned per one symbol is set to a value that satisfies the following expression:

2<sup>(N−

P−

1)</sup>≧

N

22. A multicarrier radio communication method according to claim 17, wherein said acquisition step comprising:

a reception step of receiving reception quality information on the reception quality of each subcarrier estimated on the receiving side; and

a decision step of deciding said assignment presence/absence information based on the reception quality information received in said reception step.

23. A multicarrier radio communication method according to claim 17, wherein said acquisition step comprises a reception step of receiving said assignment presence/absence information decided on the receiving side.

24. A multicarrier radio communication method according to claim 17, wherein said acquisition step comprising:

a first estimation step of estimating a delay profile of a received signal;

a second estimation step of estimating the reception quality information on the reception quality of each subcarrier using the delay profile estimated in said first estimation step; and

a decision step of deciding said assignment presence/absence information based on the reception quality information estimated in said second estimating step.

25. A multicarrier radio communication method for a multicarrier reception apparatus that carries out radio communication with a multicarrier transmission apparatus using a multicarrier radio communication method according to claim 22, comprising:

an estimation step of estimating reception quality information on the reception quality of each subcarrier; and

a transmission step of transmitting the reception quality information estimated in said estimation step.

26. A multicarrier radio communication method for a multicarrier reception apparatus that carries out radio communication with a multicarrier transmission apparatus using a multicarrier radio communication method according to claim 23, comprising:

an estimation step of estimating reception quality information on the reception quality of each subcarrier;

a decision step of deciding assignment presence/absence information on whether transmit power is assigned to each subcarrier or not based on the reception quality information estimated in said estimation step; and

a transmission step of transmitting the assignment presence/absence information decided in said decision step.

27. A multicarrier transmission apparatus that carries out radio communication by spreading signals in a frequency axis direction, comprising:

an acquisition section that acquires reception level information on a reception level of each subcarrier on the receiving side; and

a control section that controls transmit power of each subcarrier based on the reception level information acquired by said acquisition section so that subcarriers with higher reception levels have greater transmit power and subcarriers with lower reception levels have smaller transmit power.

28. A multicarrier transmission apparatus according to claim 27, wherein said control section carries out said subcarrier transmit power control so that a total value of transmit power of all subcarriers per one symbol is kept constant.

29. A multicarrier reception apparatus that carries out radio communication with a multicarrier transmission apparatus according to claim 27, comprising:

a detection section that detects reception level information on a reception level of each subcarrier; and

a transmission section that transmits the reception quality information detected by said detection section.

30. A base station apparatus comprising a multicarrier transmission apparatus according to claim 27.

31. A mobile station apparatus comprising a multicarrier reception apparatus according to claim 29.

32. A mobile station apparatus comprising a multicarrier transmission apparatus according to claim 27.

33. A base station apparatus comprising a multicarrier reception apparatus according to claim 29.

34. A multicarrier radio communication method for a multicarrier transmission apparatus that carries out radio communication by spreading signals in a frequency axis direction, comprising:

an acquisition step of acquiring reception level information on a reception level of each subcarrier on the receiving side; and

a control step of controlling transmit power of each subcarrier based on the reception level information acquired in said acquisition step so that subcarriers with higher reception levels have greater transmit power and subcarriers with lower reception levels have smaller transmit power.

35. A multicarrier radio communication method according to claim 34, wherein in said control step, said subcarrier transmit power control is carried out so that a total value of transmit power of all subcarriers per one symbol is kept constant.

36. A multicarrier radio communication method for a multicarrier reception apparatus that carries out radio communication with a multicarrier transmission apparatus using a multicarrier radio communication method according to claim 34, comprising:

a detection step of detecting reception level information on a reception level of each subcarrier; and

a transmission step of transmitting the reception quality information detected in said detection step.

37. A multicarrier transmission apparatus that carries out radio communication based on an OFDM system, comprising:

an acquisition section that acquires reception level information on a reception level of each subcarrier on the receiving side; and

a control section that controls transmit power of each subcarrier based on the reception level information acquired by said acquisition section so that subcarriers with higher reception levels have greater transmit power and subcarriers with lower reception levels have smaller transmit power.

38. A multicarrier transmission apparatus according to claim 37, wherein said control section carries out said subcarrier transmit power control so that a total value of transmit power of all subcarriers per one symbol is kept constant.

39. A multicarrier reception apparatus that carries out radio communication with a multicarrier transmission apparatus according to claim 37, comprising:

a detection section that detects reception level information on a reception level of each subcarrier; and

a transmission section that transmits the reception quality information detected by said detection section.

40. A base station apparatus comprising a multicarrier transmission apparatus according to claim 37.

41. A mobile station apparatus comprising a multicarrier reception apparatus according to claim 39.

42. A mobile station apparatus comprising a multicarrier transmission apparatus according to claim 37.

43. A base station apparatus comprising a multicarrier reception apparatus according to claim 39.

44. A multicarrier radio communication method for a multicarrier transmission apparatus that carries out radio communication based on an OFDM system, comprising:

an acquisition step of acquiring reception level information on a reception level of each subcarrier on the receiving side; and

a control step of controlling transmit power of each subcarrier based on the reception level information acquired in said acquisition step so that subcarriers with higher reception levels have greater transmit power and subcarriers with lower reception levels have smaller transmit power.

45. A multicarrier radio communication method according to claim 44, wherein in said control step, said subcarrier transmit power control is carried out so that a total value of transmit power of all subcarriers per one symbol is kept constant.

46. A multicarrier radio communication method for a multicarrier reception apparatus that carries out radio communication with a multicarrier transmission apparatus using a multicarrier radio communication method according to claim 44, comprising:

a detection step of detecting reception level information on a reception level of each subcarrier; and

a transmission step of transmitting the reception quality information detected in said detection step.