Radio communication system using variable packet length
First Claim
1. A radio communication system comprising:
- a terminal station installed on a mobile object; and
a base station provided along a traveling route of the mobile object, wherein the base station forms a limited communication area and performs radio communication with the terminal station when the terminal station is in the communication area, wherein the base station transmits a radio signal of a predetermined reference frequency toward the terminal station, and the terminal station receives the radio signal from the base station, and wherein the terminal station detects a mobile object traveling speed based on a difference between a frequency of the received radio signal and the predetermined reference frequency, and communicates the detected mobile object traveling speed to the base station.
1 Assignment
0 Petitions
Accused Products
Abstract
A radio communication system performs radio communication between a terminal station installed on a vehicle and a plurality of base stations provided along a roadside. The system detects a vehicle traveling speed in each communication area formed by each base station. The vehicle traveling speed is detected by a method which uses radio communication between the terminal station and the base stations. The time of the vehicle stay in the communication area is estimated based on the detected vehicle traveling speed, and the length of a packet is determined based on the estimated time of the vehicle stay in the communication area. In this way, the present system performs data transmission using a packet of an appropriate length according to the detected vehicle traveling speed.
-
Citations
41 Claims
-
1. A radio communication system comprising:
-
a terminal station installed on a mobile object; and
a base station provided along a traveling route of the mobile object, wherein the base station forms a limited communication area and performs radio communication with the terminal station when the terminal station is in the communication area, wherein the base station transmits a radio signal of a predetermined reference frequency toward the terminal station, and the terminal station receives the radio signal from the base station, and wherein the terminal station detects a mobile object traveling speed based on a difference between a frequency of the received radio signal and the predetermined reference frequency, and communicates the detected mobile object traveling speed to the base station. - View Dependent Claims (7, 13, 19, 38, 39)
-
-
2. A radio communication system comprising:
-
a terminal station installed on a mobile object; and
a base station provided along a traveling route of the mobile object, wherein the base station forms a limited communication area and performs radio communication with the terminal station when the terminal station is in the communication area, wherein the base station transmits a radio signal of a predetermined reference bit rate and a predetermined reference frequency toward the terminal station, and the terminal station receives the radio signal from the base station, and wherein the terminal station detects a mobile object traveling speed based on a difference between a bit rate of the received radio signal and the predetermined reference bit rate, and communicates the detected mobile object traveling speed to the base station. - View Dependent Claims (8, 14, 20)
-
-
3. A radio communication system comprising:
-
a terminal station installed on a mobile object; and
a base station provided along a traveling route of the mobile object, wherein the base station forms a limited communication area and performs radio communication with the terminal station when the terminal station is in the communication area, wherein the terminal station transmits a radio signal of a predetermined reference frequency toward the base station, and the base station receives the radio signal from the terminal station, and wherein the base station detects a mobile object traveling speed based on a difference between a frequency of the received radio signal and the predetermined reference frequency. - View Dependent Claims (10, 15, 21)
-
-
4. A radio communication system comprising:
-
a terminal station installed on a mobile object; and
a base station provided along a traveling route of the mobile object, wherein the base station forms a limited communication area and performs radio communication with the terminal station when the terminal station is in the communication area, wherein the terminal station transmits a radio signal of a predetermined reference bit rate and a predetermined reference frequency toward the base station, and the base station receives the radio signal from the terminal station, and wherein the base station detects a mobile object traveling speed based on a difference between a bit rate of the received radio signal and the predetermined reference bit rate. - View Dependent Claims (11, 16, 22)
-
-
5. A radio communication system comprising:
-
a terminal station installed on a mobile object; and
a base station provided along a traveling route of the mobile object, wherein the base station forms a limited communication area and performs radio communication with the terminal station when the terminal station is in the communication area, wherein the base station transmits a non-modulated radio signal of a reference frequency toward the terminal station, and the terminal station receives the non-modulated radio signal from the base station, wherein the terminal station modulates the received non-modulated radio signal by a predetermined modulation technique and transmits the modulated signal toward the base station, and wherein the base station detects a mobile object traveling speed based on a difference between a frequency of the received modulated radio signal and the reference frequency of transmitted non-modulated radio signal. - View Dependent Claims (12, 17, 23)
-
-
6. A radio communication system comprising:
-
a terminal station installed on a mobile object; and
a base station provided along a traveling route of the mobile object, wherein the base station forms a limited communication area and performs radio communication with the terminal station when the terminal station is in the communication area, and wherein the terminal station has a speed detection device which detects a mobile object traveling speed by using a speed sensor installed on the mobile object or GPS, and communicates the mobile object traveling speed detected by the speed detection device to the base station so that the base station controls the radio communication with the terminal station based on the received traveling speed. - View Dependent Claims (9, 18, 24)
-
-
25. A terminal station being installed on a mobile object and performing radio communication with a base station provided along a traveling route of the mobile object,
wherein the base station transmits a radio signal of a predetermined reference frequency, wherein the terminal station receives the radio signal from the base station, and analyzes a frequency of the received radio signal, and wherein the terminal station detects a mobile object traveling speed based on a difference between the analyzed frequency and the predetermined reference frequency, and communicates the detected mobile object traveling speed to the base station.
-
26. A terminal station being installed on a mobile object and performing radio communication with a base station provided along a traveling route of the mobile object,
wherein the base station transmits a radio signal of a predetermined reference bit rate and a predetermined reference frequency, wherein the terminal station receives the radio signal from the base station, and analyzes a bit rate of the received radio signal, and wherein the terminal station detects a mobile object traveling speed based on a difference between the analyzed bit rate and the predetermined reference bit rate, and communicates the detected mobile object traveling speed to the base station.
-
27. A base station being provided along a traveling route of a mobile object on which a terminal station is installed, and performing radio communication with a terminal station which is in a communication area formed by the base station,
wherein the terminal station transmits a radio signal of a predetermined reference frequency, wherein the base station receives the radio signal and analyzes a frequency of the received radio signal, and wherein the base station detects a mobile object traveling speed based on a difference between the analyzed frequency and the predetermined frequency.
-
28. A base station being provided along a traveling route of a mobile object on which a terminal station is installed, and performing radio communication with a terminal station which is in a communication area formed by the base station,
wherein the terminal station transmits a radio signal of a predetermined reference bit rate and a predetermined reference frequency, wherein the base station receives the radio signal and analyzes a bit rate of the received radio signal, and wherein the base station detects a mobile object traveling speed based on a difference between the analyzed bit rate and the predetermined bit rate.
-
33. A radio communication system comprising a terminal station installed on a mobile object and a plurality of base stations provided along a traveling route of the mobile object, each of the base stations forming a limited communication area and performing radio communication with the terminal station which is in the corresponding communication area,
wherein if data transmission between a base station and a terminal station cannot be completed in one communication area corresponding to the base station, data is divided and transmitted in a plurality of communication areas corresponding to base stations arranged in a traveling direction of the mobile object, and wherein a mobile object traveling speed is detected, and data transmission is performed using a packet of an appropriate length according to the detected mobile object traveling speed.
Specification