Multi point wireless transmission repeater system and wireless equipments

• US 20030124976A1
• Filed: 07/11/2002
• Published: 07/03/2003
• Est. Priority Date: 12/28/2001
• Status: Active Grant

• Current Assignee: Hitachi, Ltd., Hitachi Cable Limited (Proterial Ltd.)
• Original Assignee: Hitachi, Ltd., Hitachi Cable Limited (Proterial Ltd.)
• Inventors: Yano, Takashi, Tamaki, Tsuyoshi, Sakai, Katsumi
• Granted Patent: US 7,139,527 B2
• Time in Patent Office: Days
• US Class Current: 455/15
• CPC Class Codes: H04B 7/0669 using different channel coding between antennas space-time coding H04L1/0618
• CPC Class Codes: H04B 7/2606 Arrangements for base station coverage control, e.g. by using relays in tunnels

Abstract

A communication system having an excellent communication path capacity characteristic even in an insight transmission environment in which a transmitter and a receiver can see each other directly in an MIMO communication system and a wireless communication device for the communication system, including: a wireless device having a transmitter for distributing transmission data including encoded data and a training signal to a plurality of antennas, and transmitting the data as radio signals from the plurality of antennas at a predetermined timing; a plurality of wireless devices having repeaters each for receiving the radio signal, storing the radio signal into a buffer so that the radio signal is delayed by predetermined time, and transmitting the radio signal delayed; and a wireless device having a receiver for receiving the radio signals from the plurality of second wireless devices by a plurality of antennas and demodulating the encoded data by using the training signal multiplexed on the received radio signal. Each wireless device determines whether relaying operation is necessary or not and transmits a control signal for controlling the relaying operation.

Claims

1. A wireless transmission repeater system comprising:

a first wireless device having a transmitter for distributing transmission data including encoded data and a training signal to a plurality of antennas, and transmitting the data as radio signals from said plurality of antennas at a predetermined timing;

a plurality of second wireless devices having repeaters each for receiving said radio signal, storing said radio signal into a buffer so that said radio signal is delayed by predetermined time, and transmitting said radio signal delayed; and

a third wireless device having a receiver for receiving the radio signals from said plurality of second wireless devices by a plurality of antennas and demodulating said encoded data by using said training signal multiplexed on the received radio signal.

8. The wireless transmission repeater system according to claim 1, wherein either said first or second wireless device is fixedly mounted in a position, and a reflector for reflecting the radio signal in place of said second wireless device is disposed in an insight range in which the reflector can be directly seen by said fixedly disposed wireless device.

2. A wireless transmission repeater system comprising:

a first wireless device having a transmitter including means for distributing encoded data to a plurality of antennas, means for multiplexing a training signal for restoring the distributed data on a reception side onto said data, and means for controlling a transmission timing, the transmitter for transmitting radio signals from the plurality of antennas;

a second wireless device having a repeater including means for receiving the signal transmitted from said first wireless device and storing the signal into a buffer, and means for delaying the stored signal by predetermined time to thereby control a timing of transmitting the signal; and

a third wireless device having a receiver including means for controlling a reception timing to receive the radio signals transmitted from said second wireless device by a plurality of antennas, means for restoring the data distributed from the transmitter of said first wireless device to the plurality of antennas by using said training signal multiplexed on the received radio signal, and means for parallel-to-serial converting the data distributed to the plurality of antennas to combine the distributed data into encoded data, thereby obtaining reception data.

3. The wireless transmission repeater system according to claim 2, wherein the encoding means of said first wireless device has encoding means for adding redundancy to said encoded data so that error in the data is corrected, and the receiver of said third wireless device has means for performing an error correction decoding process on said encoded data by using said redundancy.

4. The wireless transmission repeater system according to claim 2, wherein said first, second, and third wireless devices are a base station, a repeater station, and a mobile station, respectively,

said mobile station measures a reception power of a pilot signal periodically transmitted from said base station, when the reception power of said pilot signal is equal to or higher than a threshold value, notifies said base station of a demand to start relaying by the repeater station, and when the reception power of said pilot signal is lower than the threshold value, notifies said base station of a demand to stop relaying by the repeater station,

when said relay start demand is received, said base station instructs said repeater station to start the relaying operation, and when said relay stop demand is received, said base station instructs said repeater station to stop the relaying operation.

5. The wireless transmission repeater system according to claim 2, wherein said first, second, and third wireless devices are a base station, a repeater station, and a mobile station, respectively,

said mobile station measures a signal-to-noise ratio of a pilot signal periodically transmitted from said base station, when the signal-to-noise ratio of said pilot signal is equal to or higher than a threshold value, notifies said base station of a demand to start relaying,by the repeater station, and when the signal-to-noise ratio of said pilot signal is lower than the threshold value, notifies said base station of a demand to stop relaying by the repeater station,

when said relay start demand is received, said base station instructs said repeater station to start the relaying operation, and when said relay stop demand is received, said base station instructs said repeater station to stop the relaying operation.

6. The wireless transmission repeater system according to claim 2, wherein said first, second, and third wireless devices are a base station, a repeater station, and a mobile station, respectively,

said mobile station measures a signal-to-noise ratio of a pilot signal periodically transmitted from said base station, presumes a propagation path by using said training signal, calculates a communication capacity from said signal-to-noise ratio and the result of said propagation path estimation, when said communication capacity is equal to or lower than a threshold value, notifies said base station of a demand to start relaying by the repeater station, when said communication capacity is higher than the threshold, notifies said base station of a demand to stop the relaying by the repeater station,

when said relay start demand is received, said base station instructs said repeater station to start the relaying operation, and when the relay stop demand is received, said base station instructs said repeater station to stop the relaying operation.

7. The wireless transmission repeater system according to claim 2, wherein the base station notifies the repeater station and the mobile station of an offset of each of a transmission timing of the transmitter, a reception timing and a transmission timing of the repeater, and a reception timing of the receiver with respect to the pilot signal as a reference which is periodically transmitted from said base station by using a control signal, to thereby determine operation timings at the time of relaying operation.

9. The wireless transmission repeater system according to claim 2, wherein either said first or second wireless device is fixedly mounted in a position, and a reflector for reflecting the radio signal in place of said second wireless device is disposed in an insight range in which the reflector can be directly seen by said fixedly disposed wireless device.

10. A mobile station for use in a wireless transmission repeater system for performing wireless communication in an MIMO communication system in which a plurality of repeater stations are disposed between a mobile station and a base station, comprising:

a separator for separating a control signal and transmission data from said base station from a reception signal;

a receiver for restoring the separated transmission data;

a repeater judgment part for judging whether relaying operation by said plurality of repeater stations is necessary or not on the basis of the control signal from said reception signal;

a transmitter for generating data to be transmitted and transmitting the data; and

a control part for controlling said receiver and transmitter by using said control signal, generating a control signal of a relay start demand or a relay stop demand to said base station in accordance with a result of judgment of said relay judgment part, and adding the control signal of said relay start demand or relay stop demand to said data to be transmitted.

11. A base station for use in a wireless transmission repeater system for performing wireless communication in accordance with an MIMO communication system, in which a plurality of repeater stations are disposed between a mobile station and a base station, comprising:

a separator for separating a control signal and transmission data from said base station from a reception signal;

a receiver for restoring the separated transmission data;

a repeater judgment part for judging whether relaying operation by said plurality of repeater stations is necessary or not on the basis of the control signal from said reception signal;

a transmitter for generating data to be transmitted and transmitting the data; and

a control part for controlling said receiver and transmitter by using said control signal, generating a control signal of a relay operation instruction to said base station and repeater station in accordance with a result of judgment of said relay judgment part, and adding the control signal of said operation instruction to said data to be transmitted.

13. The repeater station according to claim 11, further comprising a transmission/reception part for performing a wireless communication which is not according to the MIMO communication system.

12. A repeater station for use in a wireless transmission repeater system for performing wireless communication in accordance with an MIMO communication system, in which a plurality of repeater stations are disposed between a mobile station and a base station, comprising:

a separator for separating a control signal and transmission data from said mobile station or base station from a reception signal;

a repeater for buffering the separated transmission data;

a repeater judgment part for judging whether relaying operation is necessary or not by measuring a power of a base station pilot signal included in said control signal or said transmission data;

a calculation part for obtaining a transmission timing by using said base station pilot signal; and

a transmitter for transmitting transmission data of said repeater at said transmission timing.