RADIO COMMUNICATION SYSTEM AND TRANSMITTING APPARATUS USED FOR THE SAME

• US 20110032973A1
• Filed: 04/22/2009
• Published: 02/10/2011
• Est. Priority Date: 04/22/2008
• 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: Miyamoto, Shinichi, Ibi, Shinsuke, Sampei, Seiichi, To, Shimpei, Yokomakura, Kazunari, Kubota, Minoru, Nakamura, Osamu, Hamaguchi, Yasuhiro
• Granted Patent: US 8,995,540 B2
• Time in Patent Office: Days
• US Class Current: 375/141
• CPC Class Codes: H04J 11/00 Orthogonal multiplex systems, e.g. using WALSH codesH04J13/00 takes precedence
• CPC Class Codes: H04L 25/03171 Arrangements involving maximum a posteriori probability [MAP] detection
• CPC Class Codes: H04L 27/2636 with FFT or DFT modulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] transmitter or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• 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: H04W 72/563 of the wireless resources

Abstract

To provide a system that can accommodate a greater number of terminals within a limited band and can obtain a higher transmission rate. While the number of frequency signals (spectrums) output in parallel by performing a spread spectrum from the DFT unit of each terminal is 12, the number of sub-carriers constituting one sub-channel is set at 10 or 11. In this case, the users (users A and G) allocated to the sub-channels at both ends of the band will not perform transmission of one frequency signal at the end (one sub-carrier) of all the frequency signals output from the DFT unit, whereas the users (users B to F) allocated to the other sub-channels will not perform transmission of the frequency signals at the ends (two sub-carriers). This transmission can be realized by deleting (clipping) the associated number of signals from both ends or from one end of the frequency signals output from the DFT unit of each terminal and allocating the frequency signals after clipping, to individual sub-channels.

Claims

1-11. -11. (canceled)

12. A radio communication system comprising:

a transmitting apparatus that generates a first spread spectrum signal by performing a spread spectrum of a time-domain information signal and transmits the spread spectrum transmitting signal by allocating the spread spectrum transmitting signal to any one of a plurality of contiguous frequency channels defined in a constant frequency band formed of a plurality of sub-carriers and to any one of a plurality of time channels defined as having a constant time length; and

a receiving apparatus for receiving the transmitting signal, wherein

the number of sub-carriers N that constitute one of the frequency channels is previously set so as to be lower than the number of sub-carriers M that constitute the first spread spectrum signal,

the transmission apparatus generates a second spread spectrum signal by deleting part of the first spread spectrum signal by (M−

N) sub-carriers in order to allocate the transmitting signal to the frequency channel and transmits the second spread spectrum signal by allocating the second spread spectrum signal to the frequency channel, and,

the receiving apparatus receives the transmitted signal from the transmitting apparatus and performs a reproducing process of the information signal to be noticed by the first spread spectrum signal, based on the received signal,

whereby the information signal should be sent by M sub-carriers is noticed using the frequency channel formed of N sub-carriers.

13. The radio communication system according to claim 12, wherein the receiving apparatus reproduces the information signal by performing non-liner iteration equalization on the received signal.

14. The radio communication system according to claim 12, wherein one or more frequency channel whose number of sub-carriers that constitute the frequency channel is different from that of the other frequency channels is included.

15. The radio communication system according to claim 12, wherein one or more time channel whose number of the frequency channels that constitute the time channel is different from that of the other time channels is included.

16. The radio communication system according to claim 12, wherein the transmitting apparatus deletes a signal for (M−

N)/2 sub-carriers at both ends of the first spread spectrum signal.

17. The radio communication system according to claim 12, wherein the transmitting apparatus deletes a signal for (M−

N) sub-carriers at one end of the first spread spectrum signal.

18. A transmitting apparatus that generates a first spread spectrum signal formed of M sub-carriers by performing a spread spectrum of a time-domain information signal and transmits the spread spectrum transmitting signal by allocating the spread spectrum transmitting signal to any one of a plurality of contiguous frequency channels defined in a constant frequency band formed of a plurality of sub-carriers and to any one of a plurality of time channels defined as having a constant time length,

wherein

when the number of sub-carriers constituting one of the frequency channels is N which is smaller than M, in order to allocate the transmitting signal to the frequency channel, the transmitting apparatus deletes part of the first spread spectrum signal by (M−

N) sub-carriers to generate a second spread spectrum signal and transmits the second spread spectrum signal by allocating the second spread spectrum signal to the frequency channel.

19. The transmitting apparatus according to claim 18, wherein signals for (M−

N)/2 sub-carriers are deleted at both ends of the first spread spectrum signal.

20. The transmitting apparatus according to claim 18, wherein a signal for (M−

N) sub-carriers is deleted at one end of the first spread spectrum signal.

21. The receiving apparatus that receives a signal transmitted from a transmitting apparatus that generates a first spread spectrum signal formed of M sub-carriers by performing a spread spectrum of a time-domain information signal, transmits the spread spectrum transmitting signal by allocating the spread spectrum transmitting signal to a frequency channel formed of N sub-carriers which is smaller than M, wherein

the receiving apparatus, based on the received signal in the frequency channel formed of the N sub-carriers, performs a reproducing process of the information signal to be noticed by the first spread spectrum signal formed of the M sub-carriers.

22. The receiving apparatus according to claim 21, wherein the receiving signal is subjected to non-linear iterative equalization to reproduce the information signal.