RADIO COMMUNICATION DEVICE, AND RECEPTION QUALITY ESTIMATION METHOD

• US 20100266078A1
• Filed: 09/25/2008
• Published: 10/21/2010
• Est. Priority Date: 09/28/2007
• Status: Abandoned Application

• Current Assignee: Kyocera Corporation
• Original Assignee: Kyocera Corporation
• Inventors: Okino, Kenta, Nakayama, Taku
• Application Number:
  US12/680,543
• Publication Number:
  US 20100266078A1
• Time in Patent Office: Days
• US Class Current: 375/346
• CPC Class Codes: H04B 17/336 Signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR]
• CPC Class Codes: H04L 1/20 using signal quality detector
• CPC Class Codes: H04L 2025/03414 Multicarrier
• CPC Class Codes: H04L 25/0204 of multiple channels
• CPC Class Codes: H04L 25/022 of frequency response
• CPC Class Codes: H04L 25/03159 operating in the frequency domain H04L25/03165, H04L25/03178 take precedence
• CPC Class Codes: H04L 27/26526 with inverse FFT [IFFT] or inverse DFT [IDFT] demodulators, e.g. standard single-carrier frequency-division multiple access [SC-FDMA] receiver or DFT spread orthogonal frequency division multiplexing [DFT-SOFDM]
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT

Abstract

A radio base station 1100 comprises a frequency-domain/time-domain converter 1160 for converting transfer route estimation information again into a time domain signal series or a signal series in a time domain, and a time domain SNR estimator 1170 for calculating the signal power of a radio signal on the basis of the time domain signal series contained in a time band (ts), of the whole time domain containing the time domain signal series converted again, and for calculating a noise power on the basis of the time domain signal series contained in a time band (tn), thereby to estimate the signal-to-noise ratio of the radio signal.

Claims

1. A radio communication device that converts a received radio signal into a signal sequence in frequency domain, and calculates channel estimation information on the basis of a known signal included in the radio signal, the channel estimation information indicating estimation of a state of a channel of the radio signal, the radio communication device comprising:

a re-converter configured to re-convert the channel estimation information into a time-domain signal sequence which is a signal sequence in time domain;

a divider configured to divide a total time range including the time-domain signal sequence obtained by the re-conversion by the re-converter, into a first time range and a second time range, the first time range including a signal component whose amplitude of the time-domain signal sequence exceeds a predetermined threshold, the second time range being a time range other than the first time range; and

an SNR estimator configured to estimate a signal-to-noise ratio of the radio signal by calculating a signal power of the radio signal on the basis of the time-domain signal sequence included in the first time range, and by calculating a noise power on the basis of the time-domain signal sequence included in the second time range.

2. The radio communication device according to claim 1, wherein the divider determines a division position between the first time range and the second time range in accordance with a multipath state of the radio signal.

3. The radio communication device according to claim 2, wherein the divider determines the division position on the basis of a reception timing of a delay wave of the radio signal.

4. The radio communication device according to claim 1, wherein the radio signal is formed according to an orthogonal frequency division multiplexing scheme, and includes a guard interval preventing interference between symbols, and

the divider determines a division position between the first time range and the second time range on the basis of a time length of the guard interval.

5. The radio communication device according to claim 1, wherein the re-converter converts only the channel estimation information in the known signal into the time-domain signal sequence.

6. The radio communication device according to claim 5, wherein

the radio signal is formed of a plurality of subcarriers using different frequency bands,

the radio signal includes a plurality of the known signals, and

the plurality of known signals are arranged at a predetermined interval in a frequency-axis direction.

7. The radio communication device according to claim 6, wherein

the plurality of known signals form a plurality of the predetermined intervals, and

the plurality of predetermined intervals are equal to each other.

8. The radio communication device according to claim 6, wherein

the plurality of known signals form a plurality of the predetermined intervals, and

the plurality of predetermined intervals include:

a first pattern in which an interval between the known signals is a first interval; and

a second pattern in which an interval between the known signals is a second interval.

9. The radio communication device according to claim 8, wherein the first pattern and the second pattern overlap each other in the frequency-axis direction.

10. The radio communication device according to claim 8, wherein the interval between the known signals in the first pattern is different from the interval between the known signals in the second pattern.

17. The radio communication device according to claim 9, wherein the interval between the known signals in the first pattern is different from the interval between the known signals in the second pattern.

11. A radio communication device that converts a received radio signal into a signal sequence in frequency domain, and calculates channel estimation information on the basis of a known signal included in the radio signal, the channel estimation information indicating estimation of a state of a channel of the radio signal, the radio communication device comprising:

a re-converter configured to re-convert the channel estimation information into a time-domain signal sequence which is a signal sequence in time domain;

a divider configured to divide a total time range including the time-domain signal sequence obtained by the re-conversion by the re-converter, into a first time range and a second time range, the first time range including a signal component whose amplitude of the time-domain signal sequence exceeds a predetermined threshold, the second time range being a time range other than the first time range; and

a noise-power calculator configured to calculate a noise power of the radio signal on the basis of the time-domain signal sequence included in the second time range, wherein

the divider determines a division position between the first time range and the second time range in accordance with a multipath state of the radio signal.

12. A radio communication device that converts a received radio signal into a signal sequence in frequency domain, and calculates channel estimation information on the basis of a known signal included in the radio signal, the channel estimation information indicating estimation of a state of a channel of the radio signal, the radio communication device comprising:

a re-converter configured to re-convert the channel estimation information into a time-domain signal sequence which is a signal sequence in time domain;

a divider configured to divide a time range including the time-domain signal sequence obtained by the re-conversion by the re-converter, into a first time range and a second time range, the first time range including a signal component whose amplitude of the time-domain signal sequence exceeds a predetermined threshold, the second time range being a time range other than the first time range; and

a noise-power calculator configured to calculate a noise power of the radio signal on the basis of the time-domain signal sequence included in the second time range, wherein

the re-converter converts only the channel estimation information in the known signal into the time-domain signal sequence.

13. A reception quality estimation method for a radio communication device that converts a received radio signal into a signal sequence in frequency domain, and calculates channel estimation information on the basis of a known signal included in the radio signal, the channel estimation information indicating estimation of a state of a channel of the radio signal, the reception quality estimation method comprising the steps of:

re-converting the channel estimation information into a time-domain signal sequence which is a signal sequence in time domain;

dividing a total time range including the time-domain signal sequence obtained by the re-conversion, into a first time range and a second time range, the first time range including a signal component whose amplitude of the time-domain signal sequence exceeds a predetermined threshold, the second time range being a time range other than the first time range; and

estimating a signal-to-noise ratio of the radio signal by calculating a signal power of the radio signal on the basis of the time-domain signal sequence included in the first time range, and by calculating a noise power on the basis of the time-domain signal sequence included in the second time range.

14. The reception quality estimation method according to claim 13, wherein, in the reconversion step, only the channel estimation information in the known signal is converted into the time-domain signal sequence.

15. A reception quality estimation method for a radio communication device that converts a received radio signal into a signal sequence in frequency domain, and calculates channel estimation information on the basis of a known signal included in the radio signal, the channel estimation information indicating estimation of a state of a channel of the radio signal, the reception quality estimation method comprising the steps of:

re-converting the channel estimation information into a time-domain signal sequence which is a signal sequence in time domain;

dividing a time range including the time-domain signal sequence obtained by the re-conversion, into a first time range and a second time range, the first time range including a signal component whose amplitude of the time-domain signal sequence exceeds a predetermined threshold, the second time range being a time range other than the first time range; and

calculating a noise power of the radio signal on the basis of the time-domain signal sequence included in the second time range, wherein

in the noise-power calculation step, a division position between the first time range and the second time range is determined in accordance with a multipath state of the radio signal.

16. A reception quality estimation method for a radio communication device that converts a received radio signal into a signal sequence in frequency domain, and calculates channel estimation information on the basis of a known signal included in the radio signal, the channel estimation information indicating estimation of a state of a channel of the radio signal, the reception quality estimation method comprising the steps of:

re-converting the channel estimation information into a time-domain signal sequence which is a signal sequence in time domain;

dividing a time range including the time-domain signal sequence obtained by the re-conversion, into a first time range and a second time range, the first time range including a signal component whose amplitude of the time-domain signal sequence exceeds a predetermined threshold, the second time range being a time range other than the first time range; and

calculating a noise power of the radio signal on the basis of the time-domain signal sequence included in the second time range, wherein

in the re-conversion step, only the channel estimation information in the known signal is converted into the time-domain signal sequence.