WIRELESS COMMUNICATION SYSTEM, WIRELESS COMMUNICATION DEVICE, AND WIRELESS COMMUNICATION METHOD

• US 20120033571A1
• Filed: 04/26/2010
• Published: 02/09/2012
• Est. Priority Date: 04/24/2009
• 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: Shimezawa, Kazuyuki, Nogami, Toshizo, Yamada, Shohei
• Granted Patent: US 9,350,478 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 7/026 Co-operative diversity, e.g. using fixed or mobile stations as relays
• CPC Class Codes: H04B 7/0671 using different delays between antennas
• CPC Class Codes: H04B 7/0678 using different spreading codes between antennas code allocation H04J13/16
• CPC Class Codes: H04B 7/068 using space frequency diversity space-frequency coding H04L1/0606
• CPC Class Codes: H04B 7/0689 using different transmission schemes, at least one of them being a diversity transmission scheme
• CPC Class Codes: H04B 7/0854 using error minimizing algorithms, e.g. minimum mean squared error [MMSE], "cross-correlation" or matrix inversion
• CPC Class Codes: H04J 11/0053 using co-ordinated multipoint transmission/reception co-ordinated antenna or beam-forming aspects H04B7/022
• CPC Class Codes: H04L 1/0026 Transmission of channel quality indication
• CPC Class Codes: H04L 2001/0092 Error control systems characterised by the topology of the transmission link
• CPC Class Codes: H04L 2025/03426 transmission using multiple-input and multiple-output channels
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/0234 by non-linear interpolation
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals
• CPC Class Codes: H04L 5/0073 Allocation arrangements that take into account other cell interferences for intercell interference mitigation or co-ordination in orthogonal multiplex systems H04J11/005
• CPC Class Codes: H04W 72/541 : using the level of interference

Abstract

A wireless communication system includes a first channel state measurer and a second channel state measurer. When a second communication device measures a state of a channel between the second communication device and a first communication device using reference signals transmitted from the first communication device, the first channel measurer is configured to measure a state of the channel including an interference due to a signal transmitted from another first communication device. When measuring the state of the channel between the second communication device and the first communication device using the reference signals transmitted from the first communication device, the second channel state measurer measures the state of the channel while suppressing the interference due to the signal transmitted from the another first communication device. Accordingly, the wireless communication system can generate adequate feedback information both when cooperative communication is performed and when cooperative communication is not performed.

Claims

1. A wireless communication system comprising:

at least two first communication devices; and

at least one second communication device configured to communicate with the first communication devices,

the first communication device comprising;

a reference signal generator configured to generate reference signals; and

a radio transmitter configured to transmit the reference signals and transmit transmission data to the second communication device, and

the second communication device comprising;

a first channel state measurer configured to measure, when measuring a state of a channel between the second communication device and one of the first communication devices using the reference signals transmitted from the at least one of the first communication devices, a state of the channel including an interference due to a signal transmitted from the other one of the first communication devices; and

a second channel state measurer configured to measure, when measuring the state of the channel between the second communication device and the one of the first communication devices using the reference signals transmitted from the at least one of the first communication devices, the state of the channel while suppressing the interference due to the signal transmitted from the other one of the first communication devices.

2. The wireless communication system according to claim 1, wherein

one of the first communication device and the second communication device comprises:

a communication parameter determining unit configured to determine a communication parameter to be used when transmission from the first communication device to the second communication device is performed, and

the communication parameter determining unit is configured to determine the communication parameter using a result of measurement performed by one of the first channel state measurer and the second channel state measurer.

3. The wireless communication device according to claim 1, wherein

the reference signal generator generates the reference signal based on a sequence that is predetermined and differs between the first communication devices, and

the second channel state measurer is configured to perform a despreading process using the sequence on the reference signals transmitted from the first communication device, in order to suppress the interference due to the signal transmitted from the other one of the first communication devices.

4. The wireless communication system according to claim 1, having a first communication scheme in which a first communication device and at least one second communication device communicate with each other, and a second communication scheme in which a plurality of the first communication devices cooperatively communicate with the at least one second communication device,

wherein the first communication device further comprises a communication scheme selector configured to select one of the first and second communication schemes, and

the second communication device further comprises a communication scheme switcher configured to switch between the first and second state measurers based on the one of the first and second communication schemes which is selected by the communication scheme selector.

5. The wireless communication system according to claim 4, wherein

if the first communication scheme is selected, the communication scheme switcher is configured to switch to the first channel state measurer, and

if the second communication scheme is selected, the communication scheme switcher is configured to switch to the second channel state measurer.

6. The wireless communication system according to claim 3, wherein the second channel state measurer is configured to perform the despreading process based on a length of the sequence.

7. The wireless communication system according to claim 1, wherein the reference signal generator is configured to generate the reference signals based on a pseudo noise sequence.

8. The wireless communication system according to claim 3, wherein

the second communication device further comprises a channel estimator configured to estimate a channel variation value based on the reference signals, and

the second channel state measurer is configured to determine, based on the channel variation value, a combination of the reference signals to be subjected to the despreading process.

9. The wireless communication system according to claim 8, wherein the second channel state measure is configured to determine a combination of the reference signals to be subjected to the despreading process, based on an interference power from the first communication device present in a peripheral region.

10. The wireless communication system according to claim 8, wherein the second channel state measurer is configured to combine the reference signals spread in a frequency domain, in order to perform the despreading process.

11. The wireless communication system according to claim 8, wherein the second channel state measurer is configured to combine the reference signals spread in a time domain, in order to perform the despreading process.

12. A wireless communication device in a wireless communication system including:

at least two other wireless communication devices; and

at least one wireless communication device configured to communicate with the other wireless communication devices, the wireless communication device comprising;

a first channel state measurer configured to measure, when measuring a state of a channel between the wireless communication device and one of the other wireless communication devices using reference signals transmitted from the at least one of the other wireless communication devices, a state of the channel including an interference due to a signal transmitted from the other one of the other communication devices; and

a second channel state measurer configured to measure, when measuring the state of the channel between the wireless communication device and the one of the other wireless communication devices using the reference signals transmitted from the at least one of the other wireless communication devices, the state of the channel while suppressing the interference due to the signal transmitted from the other one of the other communication devices.

13. A wireless communication method for a wireless communication system including:

at least two first communication devices; and

at least one second communication device configured to communicate with the first communication devices, the wireless communication method comprising;

a first step of the first communication device generating reference signals;

a second step of the first communication device transmitting transmission data and the reference signals to the second communication device;

a third step of the second communication device, when measuring a state of a channel between the second communication device and one of the first communication devices using the reference signals transmitted from the at least one of the first communication devices, measuring a state of the channel including an interference due to a signal transmitted from the other one of the first communication device; and

a fourth step of the second communication device, when measuring the state of the channel between the second wireless communication device and the one of the first wireless communication devices using the reference signals transmitted from the at least one of the first wireless communication devices, the state of the channel while suppressing the interference due to the signal transmitted from the other one of the first communication devices.