Communication Method and Radio Transmitter

• US 20070258394A1
• Filed: 10/28/2005
• Published: 11/08/2007
• Est. Priority Date: 10/29/2004
• 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: Hamaguchi, Yasuhiro
• Granted Patent: US 8,488,688 B2
• Time in Patent Office: Days
• US Class Current: 370/310
• CPC Class Codes: H04L 27/2626 Arrangements specific to the transmitter only
• CPC Class Codes: H04L 27/2627 Modulators
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/26524 Fast Fourier transform [FFT] or discrete Fourier transform [DFT] demodulators in combination with other circuits for demodulation
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0039 Frequency-contiguous, i.e. with no allocation of frequencies for one user or terminal between the frequencies allocated to another
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/023 Multiplexing of multicarrier modulation signals multicarrier modulation H04L27/2601
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 72/0453 Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/0473 the resource being transmission power
• CPC Class Codes: H04W 72/20 Control channels or signalling for resource management
• CPC Class Codes: H04W 84/12 WLAN [Wireless Local Area Networks]

Abstract

Radio transmission is performed even to a communication party whose bandwidth that can be used for transmission and reception is limited without having an influence of an offset of a DC component. A radio transmitter applied to an OFDMA communication system in which a plurality of different terminals performs communication using OFDM signals at the same time that includes a mapping part that allocates transmission power to each subcarrier, and also selects a subcarrier to which minimum power of the transmission power to be allocated is allocated and modulates transmission data in units of communication slots to output the modulated data; and a transmission part for transmitting radio signals including the modulated data using each of the subcarriers.

Claims

1. A communication method in which a plurality of different terminals performs communication using OFDM signals at the same time, wherein

a transmitting terminal allocates minimum transmission power for transmission to a specific subcarrier mutually known between the transmitting terminal and a receiving terminal within a communication slot, which is a frequency band in units of access, and

the receiving terminal performs frequency conversion of a received signal assuming that a frequency of said specific subcarrier corresponds to a direct current potential and converts the frequency-converted received signal to a digital signal by using an analog to digital converter for data demodulation.

4. The communication method according to any of claims 1 to 3, wherein said minimum transmission power is zero.

5. The communication method according to claim 1, wherein said specific subcarrier mutually known between the transmitting terminal and receiving terminal is a center frequency of said communication slot.

6. The communication method according to claim 1, wherein said specific subcarrier mutually known between the transmitting terminal and receiving terminal is one of a maximum frequency and a minimum frequency of said communication slot.

7. The communication method according to any of claims 1 to 3, wherein said transmitting terminal does not allocate information data to a subcarrier to which the minimum transmission power is allocated.

2. A communication method in which a plurality of different terminals performs communication using OFDM signals at the same time, wherein

a receiving terminal performs frequency conversion of a received signal and notifies a transmitting terminal of information about whether or not a frequency of a subcarrier corresponding to a direct current potential about the received signal which was inputted to an analog to digital converter can be used for data communication, and

said transmitting terminal allocates, when said notified information indicates that the frequency of the subcarrier corresponding to the direct current potential cannot be used for data communication, minimum transmission power to said subcarrier for transmission.

3. A communication method in which a plurality of different terminals performs communication using OFDM signals at the same time, wherein

a receiving terminal performs frequency conversion of a received signal and notifies a transmitting terminal of information about whether or not a frequency of a subcarrier corresponding to a direct current potential about the received signal which was inputted to an analog to digital converter can be used for data communication, and

said transmitting terminal allocates minimum transmission power to a subcarrier of said notified frequency for transmission.

8. A radio transmitter applied to an OFDMA communication system in which a plurality of different terminals performs communication using OFDM signals at the same time, comprising:

a mapping part that allocates transmission power to each subcarrier, and also selects a subcarrier to which minimum power of said transmission power to be allocated is allocated, and modulates transmission data in units of communication slots to output the modulated data; and

a transmission part for transmitting radio signals including said modulated data using each of said subcarriers.

9. The radio transmitter according to claim 8, wherein said mapping part allocates zero to said selected subcarrier as the transmission power.

10. The radio transmitter according to claim 8 or 9, wherein said mapping part selects a subcarrier corresponding to a center of communication slots.

11. The radio transmitter according to claim 8 or 9, wherein said mapping part selects a subcarrier corresponding to a maximum frequency or a minimum frequency of a communication slot.

12. The radio transmitter according to claim 8 or 9, wherein said mapping part selects a frequency of a subcarrier corresponding to a direct current potential only if subcarrier availability information notified from a communication party indicates that the frequency cannot be used for data communication.

13. The radio transmitter according to claim 8 or 9, wherein said mapping part selects a frequency notified from a communication party.

14. The radio transmitter according to claims 8 or 9, wherein said mapping part updates a subcarrier frequency to be selected each time a communication party with which communication is performed using communication slots changes.

15. A communication method in which a plurality of different terminals performs communication using OFDM signals at the same time, wherein

a transmitting terminal allocates minimum transmission power for transmission to specific subcarriers mutually known between the transmitting terminal and a receiving terminal within a communication slot in a frequency band, which is an access unit of the receiving terminal, and

the receiving terminal selects a subcarrier from said specific subcarriers so that a receiving bandwidth falls within a system band, performs frequency conversion assuming that a frequency of said selected subcarrier corresponds to a direct current potential, and converts a frequency-converted received signal to a digital signal by using an analog to digital converter for data demodulation.

16. A radio transmitter applied to an OFDMA communication system in which a plurality of different terminals performs communication using OFDM signals at the same time, comprising:

a mapping part that allocates transmission power to each subcarrier, and also selects a specific subcarrier within a communication slot in a frequency band, which is an access unit of a receiving terminal, allocates minimum transmission power to the selected subcarrier, and modulates transmission data to output the modulated data; and

a transmission part for transmitting radio signals including said modulated data using each of said subcarriers.