Method and device for frequency hopping communication by changing a carrier frequency
AssigneeSanyo Electric Co., Ltd.
InventorTetsuichi Emi
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Abstract
A receiver block comprises a receiver circuit, a down-converter, a mixer, a modulator circuit, a decoding circuit, a synchronization circuit, a spread code control unit, and a frequency synthesizer. No synchronization holding circuit is needed. MSFK and PSK are used as a primary modulation. Synchronization is initially acquired by repeatedly mixing a part of the frequency hopping code sequence. Synchronization is improved during a period arranged separately from data communication periods. Before data transmission, the primary modulation components are fixed and transmitted for two code periods. The time changes in phases attributed to secondary modulation components will be known. After this, the primary modulation components are found.
Claims21
A communication method comprising:
- sequentially changing a carrier frequency of a carrier to transmit data according to a spread code sequence for frequency hopping;
- and
- repeatedly mixing a partial code string that is a part of the spread code sequence with a received signal and performs synchronization acquisition by judging detection level by referring to a signal obtained by the mixing.
A communication method comprising:
- sequentially changing a carrier frequency of a carrier to transmit data according to a spread, code sequence for frequency hopping, wherein at least a data communication period and a synchronization period are provided separately within a communication period;
- after synchronization acquisition, measuring a detection level during the synchronization period while shifting hopping timing;
- judging a difference in hopping timings between received and transmitted signals by comparing the detection level with detection level measured at an original timing without shift;
- and
- performing synchronization of the hopping timings between the received and transmitted signals according to the judgment.
A communication method using a primary modulation of data to be transmitted and a secondary modulation using frequency hopping, comprising:
- sequentially changing a carrier frequency of a carrier to transmit the data according to a spread code sequence for frequency hopping;
- transmitting data while fixing a primary modulation component during a predetermined period;
- and
- detecting and holding temporal changes of the primary modulation component and a secondary modulation component by comparing data receipted at different timings to thereby reproduce original data by extracting the primary modulation component of data received during data communication.
A communication method comprising:
- sequentially changing a carrier frequency of a carrier to transmit data according to a spread code sequence for frequency hopping in which one period of the spread code sequence for frequency hopping is defined as one frame and a modulation of data as a primary modulation;
- modulating data including at least phase shift as a primary modulation;
- transmitting data while fixing a phase of the primary modulation signal;
- storing a phase shift of the hopping frequency, obtained by comparing the signals received at corresponding hopping periods in two different frames, in order to determine a correction phase for the hopping period;
- deciding a reference phase for each hopping period in each frame using the correction phase;
- and
- sequentially obtaining information based on the phase shift by comparing the phase of a signal actually received during the hopping period with the corresponding reference phase.
The method as claimed 11, wherein 10 transmitter block transmits the data while fixing the frequency as well as the phase of the primary modulation signal before starting data transmission.
A communication method comprising:
- sequentially changing a carrier frequency of a carrier to transmit data according to a spread code sequence for frequency hopping in which one period of the spread code sequence for frequency hopping is defined as one frame and a modulation of data as a primary modulation;
- modulating data including at least phase shift as a primary modulation, and an angle area comprising a plurality of angle areas within one of which the phase falls is held in advance;
- and
- sequentially obtaining information based on the phase shift by individually deciding which angle area the phase of a signal received falls within in each hopping period in each frame.
A device for communication comprising;
- a receiver circuit which applies a bandpass filtering to a received signal transmitted in sequentially changed carrier frequencies according to a spread code sequence for frequency hopping,
- a frequency converter which lowers frequency of an output signal of the receiver circuit to an aimed frequency band,
- a spread control unit which performs spread control according to the spread code sequence for frequency hopping,
- a frequency synthesizer which supplies, by a control of the spread control unit, frequency corresponding to each hopping period,
- a mixer which mixes output of both the frequency synthesizer and the frequency converter,
- a demodulator circuit which demodulates at least a phase of an output signal of the mixer,
- a decoding circuit which judges a phase for each hopping period by using a demodulated phase, and
- a synchronization circuit which controls operation timings of the spread control unit according to an instruction from the demodulator circuit.
Dependencies are inferred from the claim text.