Demodulation method, information process apparatus, and reception station

Patent metadata

Field	Value
Publication number	US-9729248-B2
Application number	US-201615268863-A
Country	US
Kind code	B2
Filing date	Sep 19, 2016
Priority date	Sep 25, 2015
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

A non-transitory computer-readable recording medium on which a program is recorded for a causing a processor to execute a demodulation process. The demodulation process includes detecting a preamble of a wireless signal transmitted from a first transmission station by way of a short wavelength carrier wave, extracting a first signal superimposed on the short wavelength carrier wave, the first signal being extracted from a wireless signal that is identified in accordance with the detection of the preamble, extracting a second signal superimposed on a carrier wave transmitted from a second transmission station, and performing demodulation on a target demodulation signal obtained by superimposing the first signal on the second signal.

First claim

What is claimed is:

1. A non-transitory computer-readable recording medium on which a program is recorded for causing a processor to execute a demodulation process, the demodulation process comprising:
detecting a preamble of a wireless signal transmitted from a first transmission station by way of a short wavelength carrier wave;
extracting a first signal superimposed on the short wavelength carrier wave, the first signal being extracted from the wireless signal that is identified in accordance with the detection of the preamble;
extracting a second signal superimposed on a carrier wave transmitted from a second transmission station different from the first transmission station; and
performing demodulation on a target demodulation signal obtained by superimposing the first signal on the second signal.

2. The non-transitory computer-readable recording medium as claimed in claim 1 ,
wherein the demodulation process further comprises:
referring to a storage unit that stores types of the first signal in association with combinations of a transmission start time of the wireless signal and a frequency of the short-wave carrier wave; and
storing the first signal in a database with respect to each of the types of the first signal associated with the combinations of the transmission time of the wireless signal included in the preamble;
wherein the demodulation includes superimposing same types of signals extracted from the wireless signals.

3. The non-transitory computer-readable recording medium as claimed in claim 2 ,
wherein the superimposing includes
comparing signal strengths of the first signal with respect to each predetermined time,
obtaining a signal strength in accordance with the comparison, and
generating a target demodulation signal that is subjected to demodulation in accordance with the signal strength of the first signal with respect to each predetermined time, and

wherein the demodulation includes demodulating the target demodulation signal.

4. The non-transitory computer-readable recording medium as claimed in claim 3 , wherein the superimposing includes generating the target demodulation signal in accordance with a largest signal strength among the signal strengths of the first signal with respect to each predetermined time.

5. The non-transitory computer-readable recording medium as claimed in claim 3 , wherein the superimposing includes generating the target demodulation signal in accordance with an average strength among the signal strengths of the first signal with respect to each predetermined time.

6. The non-transitory computer-readable recording medium as claimed in claim 3 ,
wherein the preamble includes a characteristic signal included in the wireless signal,
wherein the signal extracted by the extracting includes the characteristic signal, and
wherein the demodulation does not include demodulating the characteristic signal in a case where the characteristic signal includes a disordered part.

7. The non-transitory computer-readable recording medium as claimed in claim 6 ,
wherein the superimposing further includes superimposing an ordered part of the characteristic signal instead of superimposing the disordered part of the characteristic signal.

8. The non-transitory computer-readable recording medium as claimed in claim 6 ,
wherein the characteristic signal includes a synchronization signal having a frequency that continues for a predetermined period.

9. The non-transitory computer-readable recording medium as claimed in claim 8 ,
wherein the demodulation includes comparing the synchronization signal and a waveform data of the synchronization signal stored in the storage unit, and
wherein the synchronization signal is determined as the target demodulation signal in a case where a matching degree between the synchronization signal and the waveform data is greater than or equal to a predetermined value.

10. The non-transitory computer-readable recording medium as claimed in claim 8 ,
wherein the demodulation includes determining that a start point of the synchronization signal is a reference position of the superimposing in a case where the synchronization signal continues for the predetermined period,
wherein the first signal is not superimposed in a case where the synchronization signal does not continue for the predetermined period and is not followed by a header information signal.

11. A demodulation method comprising:
detecting a preamble of a wireless signal transmitted from a first transmission station by way of a short wavelength carrier wave;
extracting a first signal superimposed on the short wavelength carrier wave, the first signal being extracted from the wireless signal that is identified in accordance with the detection of the preamble;
extracting a second signal superimposed on a carrier wave transmitted from a second transmission station different from the first transmission station; and
performing demodulation on a target demodulation signal obtained by superimposing the first signal on the second signal.

12. An information process apparatus comprising:
a processor; and
a memory that stores a program, the program causes the processor to execute a demodulation process including
detecting a preamble of a wireless signal transmitted from a first transmission station by way of a short wavelength carrier wave;
extracting a first signal superimposed on the short wavelength carrier wave, the first signal being extracted from a wireless signal that is identified in accordance with the detection of the preamble;
extracting a second signal superimposed on a carrier wave transmitted from a second transmission station; and
performing demodulation on a target demodulation signal obtained by superimposing the first signal on the second signal.

13. A non-transitory computer-readable recording medium on which a program is recorded for a causing a processor to execute a demodulation process, the demodulation process comprising:
detecting a preamble of a wireless signal transmitted from a first communication station by way of a short wavelength carrier wave;
extracting a first signal superimposed on the short wavelength carrier wave, the first signal being extracted from the wireless signal that is identified in accordance with the detection of the preamble;
extracting a second signal superimposed on a carrier wave transmitted from a second communication station different from the first communication station;
performing demodulation on a target demodulation signal obtained by superimposing the first signal on the second signal; and
transmitting the target demodulation signal to an information process apparatus.

14. A demodulation method comprising:
detecting a preamble of a wireless signal transmitted from a first communication station by way of a short wavelength carrier wave;
extracting a first signal superimposed on the short wavelength carrier wave, the first signal being extracted from the wireless signal that is identified in accordance with the detection of the preamble;
extracting a second signal superimposed on a carrier wave transmitted from a second communication station different from the first communication station;
performing demodulation on a target demodulation signal obtained by superimposing the first signal on the second signal; and
transmitting the target demodulation signal to an information process apparatus.

15. An information process apparatus comprising:
a processor configured to execute a program in accordance with the demodulation method of claim 14 .

16. An information process apparat

Assignees

• Fujitsu Ltd

Inventors

• Kono Taki

Classifications

• H04H2201/12

  digital radio mondiale [DRM] · CPC title

• H04H40/09

  Arrangements for receiving desired information automatically according to timetables · CPC title

• H04L7/06

  the synchronisation signals differing from the information signals in amplitude, polarity or frequency {or length} · CPC title

• H04L5/0048

  Allocation of pilot signals, i.e. of signals known to the receiver (allocation of control signalling H04L5/0053; use of control signalling H04L5/0091) · CPC title

• H04H60/00

  Arrangements for broadcast applications with a direct linking to broadcast information or broadcast space-time; Broadcast-related systems · CPC title