EP0984639A2
Expired / Lapsed
EP
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Automobile communications method and system
Assignee: NEC Corp
•
Filing: 1999-07-06
•
Granted: —
•
Expires: 2019-07-06
Abstract
Abstract An automobile communication system which can ensure fast hand-over without putting unnecessary burden on mobile stations and can adequately handle changes in road condition is disclosed. For each of the radio zones (RZ1-RZ5) formed by roadside transceivers (TRX1-TRX5) arranged along a road (10), a plurality of transmission and reception frequencies ft1/fr1 and ft2/fr2 are provided. The in-use transmission/reception frequencies in adjoining radio zones are switched at predetermined timing such that they are not permitted to be overlapped. By switching a time slot allocated to the vehicle-mounted transceiver, the vehicle-mounted transceiver can continuously communicate with the roadside transceivers at the same communication frequency over the radio zones. <IMAGE>
Inventors
- 👤 Yasuharu Yoshida
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-02 20:17
CPC Classifications
H; H04; H04W; H04W28/00; H04W28/16; H04W28/26; H04W16/00; H04W16/14; H04W36/00
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
123 words
An automobile communications method for an on-board
mobile station (21) in a plurality of radio zones
(RZ 1 -RZ 5 ) which are consecutively arranged along a road (10),
comprising the steps of: providing each of the radio zones with a
plurality of predetermined communication frequencies (ft1,
ft2, fr1, ft1); characterized by: controlling a communication frequency used in
each of the radio zones in time division scheme such that
simultaneous transmission at a same communication frequency
is not permitted in adjoining radio zones and different
time slots are allocated for communications at a same
communication frequency in adjoining radio zones; and switching a time slot allocated to the on-board
mobile station to continuously communicate with the on-board
mobile station over the radio zones.
Claim 2
Dependent Claim
45 words
The automobile communication method according to
claim 1, wherein the time slot used for communication with
the on-board mobile station is switched in such a manner
that communication with the on-board mobile station is
continuously performed at a same communication frequency
over the radio zones.
Claim 3
Dependent Claim
36 words
The automobile communication method according to
claim 1, wherein the time slot is switched in such a manner
that communication with the on-board mobile station is
continuously performed at different communication
frequencies over the radio zones.
Claim 4
Dependent Claim
111 words
An automobile communications method between an
on-board mobile station and a fixed station system in a
plurality of radio zones which are consecutively arranged
along a road, comprising the steps of: providing each of the radio zones with a
plurality of predetermined communication frequencies; characterized by: controlling a communication frequency used in
each of the radio zones in time division scheme such that
simultaneous transmission at a same communication frequency
is not permitted in adjoining radio zones and different
time slots are allocated for communications at a same
communication frequency in adjoining radio zones; and continuously communicating with the on-board
mobile station at a same communication frequency over the
radio zones.
Claim 5
Dependent Claim
38 words
The automobile communication method according to
claim 4, wherein the plurality of predetermined
communication frequencies in each radio zone are generated
from a single reference frequency in accordance with a
predetermined conversion to be in a frequency-coherence
state.
Claim 6
Dependent Claim
79 words
The automobile communication method according to
claim 4, wherein a predetermined number N (N is an integer
equal to or greater than 2) of time slots are determined in
one period in each of the radio zones, wherein one time
slot is assigned to a single on-board mobile station and M
(M is an integer equal to or greater than 2) predetermined
communication frequencies are sequentially switched from
one to another at a timing of every N/M time slot.
Claim 7
Dependent Claim
40 words
The automobile communication method according to
claim 6, wherein the time slot allocated to the on-board
mobile station is switched in such a way that the on-board
mobile station uses a same communication frequency over the
plurality of radio zones.
Claim 8
Dependent Claim
40 words
The automobile communication method according to
claim 4, wherein each of the predetermined communication
frequencies is used for both transmission and reception to
perform communication with the on-board mobile station
according to TDMA/TDD (Time Division Multiple Access/Time
Division Duplex) scheme.
Claim 9
Dependent Claim
70 words
The automobile communication method according to
claim 4, wherein the plurality of predetermined
communication frequencies in each radio zone are generated
from a single reference frequency in accordance with a
predetermined conversion to be in a frequency-coherence
state, wherein each of the predetermined communication
frequencies is used for both transmission and reception to
perform communication with the on-board mobile station
according to TDMA/TDD (Time Division Multiple Access/Time
Division Duplex) scheme.
Claim 10
Dependent Claim
58 words
The automobile communication method according to
claim 4, wherein the plurality of predetermined
communication frequencies comprises a plurality of
different pairs of first frequencies and second frequencies,
wherein the first frequencies are generated from one
reference frequency in accordance with a first
predetermined conversion so that the first frequencies are
in a frequency-coherence state over the radio zones.
Claim 11
Dependent Claim
39 words
The automobile communication method according to
claim 10, wherein the on-board mobile station generates a
transmission local signal of the second frequency from a
radio signal received from the fixed station system in
accordance with a second predetermined conversion.
Claim 12
Dependent Claim
57 words
The automobile communication method according to
claim 11, wherein the fixed station system generates a
reception local frequency from the first frequency in
accordance with the second predetermined conversion as used
by the on-board mobile station so that the reception local
frequency and a radio signal received from the on-board
mobile station are in a frequency-coherence state.
Claim 13
Dependent Claim
130 words
An automobile communications system comprising: an on-board mobile station (21) movable on a road
(10); a plurality of fixed stations (30) forming a
plurality of radio zones consecutively arranged on the road,
respectively, wherein the fixed stations are communicable
with the on-board mobile station using one of a plurality
of predetermined communication frequencies; characterized by: a control station (40) controlling communication
frequencies used by the plurality of fixed stations at
predetermined timing in such a way as not to permit
simultaneous transmission at a same communication frequency
in adjoining radio zones, the plurality of fixed stations performing
continuous communication with the on-board mobile station
by allocating different time slots to communications at a
same frequency in adjoining radio zones and switching a
time slot allocated to the on-board mobile station.
Claim 14
Dependent Claim
47 words
The automobile communication system according to
claim 13, wherein the time slot allocated to the on-board
mobile station is switched from one to another in such a
manner that communication with the on-board mobile station
is continuously performed at a same communication frequency
over the radio zones.
Claim 15
Dependent Claim
102 words
The automobile communication system according to
claim 13, wherein each of the plurality of fixed stations
comprises: a frequency generator (107-110) for generating
the plurality of predetermined communication frequencies
from a signal of a reference frequency inputting from the
control station; a selector (111) for selecting one communication
frequency in use from the plurality of predetermined
communication frequencies under control of the control
station; a time-division controller (105) for allocating a
time slot to communication with the on-board mobile station
at the communication frequency in use; and an interface (106) for transmission and reception
of signals to and from the control station.
Claim 16
Dependent Claim
40 words
The automobile communication system according to
claim 15, wherein each of the predetermined communication
frequencies is used for both transmission and reception to
perform communication with the on-board mobile station
according to TDMA/TDD (Time Division Multiple Access/Time
Division Duplex) scheme.
Claim 17
Dependent Claim
66 words
The automobile communication system according to
claim 15, wherein the frequency generator generates the
plurality of predetermined communication frequencies so
that the predetermined communication frequencies are
frequency-coherent to the reference frequency wherein each
of the predetermined communication frequencies is used for
transmission and reception, and wherein the time-division
controller performs communication with the on-board mobile
station according to TDMA/TDD (Time Division Multiple
Access/Time Division Duplex) scheme.
Claim 18
Dependent Claim
56 words
The automobile communication system according to
claim 15, wherein the plurality of predetermined
communication frequencies comprises a plurality of
different pairs of first frequencies and second frequencies,
wherein the frequency generator generates the first
frequencies from one reference frequency in accordance with
a first predetermined conversion so that the first
frequencies are in a frequency-coherence state.
Claim 19
Dependent Claim
58 words
The automobile communication method according to
claim 18, wherein each of the fixed stations generates a
reception local frequency from the first frequency in
accordance with a second predetermined conversion as used
by the on-board mobile station so that the reception local
frequency and a radio signal received from the on-board
mobile station are in a frequency-coherence state.
Claim 20
Dependent Claim
62 words
The automobile communication system according to
claim 13, wherein the on-board mobile station comprises: frequency-in-use regenerator (203, 207-209) for
regenerating the communication frequency in use from a
signal received from a fixed station which forms a radio
zone for communication; and a communication controller (204) controlling
communication with the fixed station using the allocated
time slot at the communication frequency in use.
Claim 21
Dependent Claim
39 words
The automobile communication system according to
claim 20, wherein each of the plurality of predetermined
communication frequencies is used for transmission and
reception, and the communication controller carries out
communication with the fixed station according to a
TDMA/TDD scheme.
Claim 22
Dependent Claim
90 words
The automobile communication system according to
claim 20, wherein each of said plurality of predetermined
communication frequencies is used for transmission and
reception frequencies, wherein the frequency-in-use regenerator
comprises: a demodulator for demodulating the received
signal, and a phase controller for performing phase control
on a signal of an oscillation frequency based on an output
of the demodulator such that the demodulator acquires
synchronization; and wherein the communication controller carries out
communication with the fixed station according to a
TDMA/TDD scheme using the oscillation frequency as a
transmission local frequency.
Claim 23
Dependent Claim
94 words
The automobile communication system according to
claim 20, wherein the frequency-in-use regenerator
comprises: a demodulator for demodulating the received
signal using an oscillation frequency, and a phase controller for performing phase control
on the signal of the oscillation frequency based on an
output of the demodulator such that the demodulator
acquires synchronization; and wherein the on-board mobile station further
comprises: a converter for generating a transmission local
frequency from the signal of the oscillation frequency in
accordance with a predetermined conversion, and a modulator for generating a transmission signal
using the transmission local frequency.
Claim 24
Dependent Claim
36 words
The automobile communication system according to
claim 23, wherein the predetermined conversion of the
converter is the same as a predetermined conversion for
generating a reception local signal from a transmission
frequency at each fixed station.
Claim 25
Dependent Claim
97 words
A fixed station in the automobile communication
system as recited in claim 13, comprising: a communication frequency generator for
generating the plurality of predetermined communication
frequencies from a signal of a reference frequency coming
from the control station; a selector for selecting one communication
frequency in use from the plurality of predetermined
communication frequencies under control of the control
station; a time-division controller for allocating a time
slot to communication with the on-board mobile station at
the communication frequency in use; and an interface for implementing transmission and
reception of signals to and from the control station.
Claim 26
Dependent Claim
37 words
The fixed station according to claim 25, wherein
each of the plurality of predetermined communication
frequencies is used for transmission and reception, and
communication with the on-board mobile station is carried
out according to a TDMA/TDD scheme.
Claim 27
Dependent Claim
66 words
The fixed station according to claim 25, wherein
each of the plurality of predetermined communication
frequencies is used for transmission and reception, the
communication frequency generator generates the plurality
of predetermined communication frequencies in each radio
zone so that the predetermined communication frequencies
are frequency-coherent to the reference frequency, and the
time-division controller carries out communication with the
on-board mobile station according to a TDMA/TDD scheme.
Claim 28
Dependent Claim
67 words
The fixed station according to claim 25, wherein
the plurality of predetermined communication frequencies
comprises a plurality of different pairs of a first
frequency and a second frequency, and the communication
frequency generator generates the first frequency from the
reference frequency in accordance with a first
predetermined conversion in such a manner that those first
frequencies are in a frequency-coherence state over the
plurality of radio zones.
Claim 29
Dependent Claim
77 words
The fixed station according to claim 25 or 28,
wherein the plurality of predetermined communication
frequencies comprises a plurality of different pairs of a
first frequency and a second frequency, and a reception
local frequency for demodulating a received radio signal
from the on-board mobile station is generated from the
first frequency in accordance with a second predetermined
conversion so that the reception local signal is frequency-coherent
to the received radio signal from the on-board
mobile station.
Claim 30
Dependent Claim
63 words
An on-board radio mobile station in the
automobile communication system as recited in claim 13,
comprising: a frequency-in-use regenerator for regenerating
the communication frequency in use from a signal received
from a fixed station which forms a radio zone for
communication; and a communication controller for communicating with
the fixed station using the allocated time slot based on
the communication frequency in use.
Claim 31
Dependent Claim
40 words
The on-board radio mobile station according to
claim 30, wherein each of the plurality of predetermined
communication frequencies is used for transmission and
reception, and the communication controller carries out
communication with the fixed station according to a
TDMA/TDD scheme.
Claim 32
Dependent Claim
90 words
The on-board radio mobile station according to
claim 30, wherein each of the plurality of predetermined
communication frequencies is used for transmission and
reception; wherein the frequency-in-use regenerator
comprises: a demodulator for demodulating the received
signal, and a phase controller performing phase control on a
signal of an oscillation frequency based on an output of
the demodulator such that the demodulator acquires
synchronization; and wherein the communication controller carries out
communication with the fixed station according to a
TDMA/TDD scheme by using the oscillation frequency as a
transmission local frequency.
Claim 33
Dependent Claim
95 words
The on-board radio mobile station according to
claim 30, wherein the frequency-in-use regenerator
comprises: a demodulator for demodulating a received signal
of an oscillation frequency, and a phase controller performing phase control on
the signal of the oscillation frequency based on an output
of the demodulator such that the demodulator acquires
synchronization; and wherein the on-board radio mobile station further
comprises: a converter for generating a transmission local
frequency from the signal of the oscillation frequency in
accordance with a predetermined conversion, and a modulator for generating a transmission signal
using the transmission local frequency.
Claim 34
Dependent Claim
37 words
The on-board radio mobile station according to
claim 30, wherein the predetermined conversion of the
converter is the same as a predetermined conversion for
generating a reception local signal from a transmission
frequency at each fixed station.
Claim 35
Dependent Claim
89 words
A control station in the automobile communication
system as recited in claim 13, comprising: a reference frequency generator for generating a
reference frequency signal for producing the plurality of
predetermined communication frequencies in each fixed
station; a communication controller for transmitting and
receiving signals to and from the plurality of fixed
stations; and a system controller controlling communication
frequencies in use by the plurality of fixed stations at
predetermined timing in such a way as not to permit
simultaneous transmission at a same communication frequency
in adjoining radio zones.
References Cited (Backward Citations)
No citation records indexed.
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