Wireless communication system

• US 20070177683A1
• Filed: 04/27/2005
• Published: 08/02/2007
• Est. Priority Date: 04/30/2004
• 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: Matsushita, Yoshiteru, Sanpei, Seiichi
• Granted Patent: US 8,320,493 B2
• Time in Patent Office: Days
• US Class Current: 375/260
• CPC Class Codes: H04L 1/0003 by switching between different modulation schemes
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01

Abstract

Improvement of transmission efficiency is sought by stopping transmission of unnecessary MLI data.

A transmitting circuit 111 in a base station apparatus 110 has an MLI modulation part 248 composed of an MLI generating circuit 238, a symbol modulation circuit 239, and an IFFT circuit 240, a user data modulation part 249 composed of an encoder circuit 234, a symbol modulation circuit 235, a transmission power control circuit 236, and an IFFT circuit 237, and a transmission operation control circuit 113. The transmission operation control circuit 113 controls operation timing of the MLI modulation part 248, the user datamodulationpart 249, and a multiplexer 243 based on a signal to notify that ACK input from a receiving circuit 112 has been received so that slots containing no MLI data are generated.

Claims

1. A modulator applied to a wireless communication system that conducts wireless communication by a multi-carrier modulation level using a communication frame composed of a plurality of slots, comprising:

a slot generation part generating said slots by multiplexing header information containing at least channel estimation information for estimating channel, modulation level information for notifying a receiving side of a modulation level of each sub-carrier, and user data; and

a determination part determining whether or not demodulation information for notifying successful demodulation of said modulation level information has been received from the receiving side, wherein,

said slot generation part, when said determination part determines that said demodulation information has been received, generates, after receiving said demodulation information, slots which do not contain said modulation level information in a relevant communication frame.

2. The modulator according to claim 1, wherein said slot generation part, when said determination part determines that said demodulation information has been received, generates, generates, after receiving said demodulation information, after generating n (n is a natural number) slots containing said modulation level information, slots which do not contain said modulation level information in a relevant communication frame.

7. The modulator according to claim 1, wherein said slot generation part, when generating slots which do not contain said modulation level information, shortens a slot length by deleting a time allocated to said modulation level information in said slots and, as a result of shortened slot length, further generates slots having a shortened slot length without containing said modulation level information in accordance with an idle time generated in said communication frame.

8. The modulator according to claim 1, wherein said slot generation part generates slots that do not contain said modulation level information without changing a slot length by allocating, instead of said modulation level information, said user data to a time to which said modulation level information is allocated in said slots.

9. A demodulator applied to a radio communication system that conducts radio communication by a multi-carrier modulation level using a communication frame composed of a plurality of slots containing at least modulation level information for notifying a receiving side of a modulation level of each sub-carrier and user data;

said modulator comprising;

a modulation level information demodulation part that extracts said modulation level information from slots generated by the modulator according to claim 1 at a transmitting side and received via a radio, and demodulates said extracted modulation level information;

a demodulation information generation part that determines whether or not said modulation level information has been successfully demodulated, and when said demodulation has been successful, generates demodulation information for notifying a transmitting side of successfuil demodulation of said modulation level information; and

a user data demodulation part that, after said demodulation information is generated, uses said successfully demodulated modulation level information to demodulate each sub-carrier corresponding to said user data in each slot existing in the same communication frame.

11. A base station appratus comprising the modulator according to claim 1.

12. A mobile ststion apparatus comprising the demodulator according to claim 9.

3. A modulator applied to a wireless communication system that conducts wireless communication by a multi-carrier modulation level using a communication frame composed of a plurality of slots;

comprising;

a slot generation part generating said slots by multiplexing header information containing at least channel estimation information for estimating channel, modulation level information for notifying a receiving side of a modulation level of each sub-carrier, and user data; and

a slot number information generation part that estimates the number of slots in which said modulation level information is to be contained and generates slot number information for notifying the receiving side of said estimated number of slots, wherein

said slot generation part generates, after generating said estimated number of slots by adding said slot number information to said modulation level information, slots which do not contain said modulation level information in a relevant communication frame.

4. The modulator according to claim 3, wherein said slot number information generation part estimates, based on channel estimation information, the number of slots in which signal power necessary for demodulating said modulation level information can be obtained.

5. The modulator according to claim 3, wherein said slot number information is information all representing the same numeric value.

6. The modulator according to claim 3, wherein said slot number information is information representing a remaining number of times of transmission of slots containing said modulation level information.

10. A demodulator applied to a wireless communication system that conducts wireless communication by a multi-carrier modulation level using a communication frame composed of a plurality of slots containing at least modulation level information to notify a receiving side of a modulation level of each sub-carrier and user data;

said modulator comprising;

an extraction part extracting said modulation level information and slot number information added to said modulation level information to indicate the number of slots containing said modulation level information existing in same said communication frame;

a modulation level/slot number information demodulation part demodulating said extracted modulation level information and slot number information; and

a user data demodulation part that determines whether or not said modulation level information and slot number information has been successfully demodulated and, when said demodulation has been successful, eztracts said number of slots to identify a last slot containing said modulation level information and slot number information based on the extracted number of slots, and uses said successfully demodulation level information to demodulate each sub-carrier corresponding to said user data of each slot existing in the same communication frame after the slot following said identified slot.

13. canceled