JP2001326959A - Method for detecting whereabouts zone, radio communication system and radio mobile station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it is difficult to detect a whereabouts zone of a radio mobile station in a radio communication system which performs plural station simultaneous transmission. SOLUTION: Each radio base station 1-i (i=1,..., n) offsets a carrier frequency fi by a value different from other radio base station 1-j (i≠j) to perform the plural station simultaneous transmission, the radio mobile station 2 detects the offset value fi of the carrier frequency, and its whereabouts zone is detected to the basis of the detected offset value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a location zone for detecting a zone in which a wireless mobile station itself is located in a wireless communication system in which an area in which a wireless mobile station operates is covered by a plurality of wireless base stations that perform multi-station simultaneous transmission. The present invention relates to a detection method, a wireless communication system thereof, and a wireless mobile station thereof.

[0002]

2. Description of the Related Art A mobile telephone system is known as a typical example of a wireless communication system in which a plurality of wireless base stations cover an area where a wireless mobile station operates. In the car phone system,
Each radio base station transmits a signal for identifying the radio base station at a frequency unique to each radio base station, and the radio mobile station checks the received signal of the highest electric field level while switching the reception frequency. The zone where the user is located is determined based on the frequency.

On the other hand, in a commercial wireless communication system for performing simultaneous broadcast to a plurality of wireless mobile stations, a large-area wireless base station that covers an area with a plurality of high-output wireless base stations is not a small-zone system such as an automobile telephone system. A zone system is used. Also, multi-station simultaneous transmission in which data of the same content is transmitted from a plurality of wireless base stations at the same time is used together. In a wireless communication system that performs multi-station simultaneous transmission, a wireless mobile station does not need to change the frequency for each wireless base station when moving between zones, and it is not necessary to change the frequency used by the wireless base station for each zone. Therefore, effective use of frequency resources becomes possible.

[0004]

Since the conventional location zone detection method, radio communication system and radio mobile station are configured as described above, in multi-station simultaneous transmission, a plurality of radio base stations transmit the same data at the same time. It is difficult to transmit a signal for identifying each base station as in the case of a mobile telephone system because the data of the content is transmitted. In a wireless communication system that performs simultaneous multi-station transmission, the location zone of the wireless mobile station is detected. There was a problem that it was difficult to do.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. Each radio base station executes radio communication by offsetting a carrier frequency by a value different from other radio base stations, and Detects the offset value of the carrier frequency, and detects its own zone based on the detected offset value, so that the wireless mobile station can detect its own zone in a wireless communication system that performs multi-station simultaneous transmission. It is an object of the present invention to obtain a possible location zone detection method, a wireless communication system, and a wireless mobile station.

[0006]

According to the present invention, there is provided a method for detecting a location zone, in which each radio base station executes radio communication by offsetting a carrier frequency by a value different from that of another radio base station, and a radio mobile station receives a signal. It detects the offset value of the carrier frequency of the signal and detects its own zone based on the detected offset value.

[0007] A location zone detecting method according to the present invention is such that a radio mobile station detects an offset value by a frequency tracking process for a carrier frequency of a received signal.

In the radio communication system according to the present invention, each radio base station executes radio communication by offsetting the carrier frequency by a value different from the other radio base stations, and the radio mobile station determines the carrier frequency of the received signal. The offset value is detected, and the own zone is detected based on the detected offset value.

In a radio communication system according to the present invention, a radio mobile station detects an offset value by performing a frequency tracking process on a carrier frequency of a received signal.

[0010] A radio mobile station according to the present invention comprises: a receiving means for receiving a radio signal from a radio base station; a demodulation means for demodulating a radio signal received by the receiving means into an original signal;
An offset frequency detecting means for detecting an offset value of a carrier frequency of a radio signal from a radio base station, and a zone determining means for detecting its own zone based on the offset value detected by the offset frequency detecting means. is there.

[0011] The radio mobile station according to the present invention is provided with frequency tracking means for executing frequency tracking processing on a carrier frequency of a radio signal to detect an offset value.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a diagram showing a configuration of a wireless communication system according to Embodiment 1 of the present invention, and FIG. 2 is a block diagram showing a configuration of a wireless mobile station according to Embodiment 1 of the present invention. FIG. 3 is a diagram illustrating an example of a correspondence relationship between the offset amount of the carrier frequency and the radio base station.

In FIG. 1, 1-1 to 1-n are values f1 to fn different from other radio base stations 1-1 to 1-n, respectively.
The carrier frequency f is offset by
, A plurality of radio base stations that perform multi-station simultaneous transmission to the radio base stations 1 to 11-n, perform radio communication with the radio base station 1-i of the zone 11-i where the base station 1 is located, and receive a reception signal. Is a wireless mobile station that detects an offset value of the carrier frequency of its own and detects its own zone based on the detected offset value.

In the radio mobile station 2 shown in FIG. 2, reference numeral 21 denotes a radio base station 1 in a zone 11-i where the radio mobile station 2 is located.
An antenna 22 receives a wireless signal from the wireless base station 1-i via the antenna 21; a reference frequency oscillator 24;
A demodulation circuit 31 that demodulates a received radio signal based on a local oscillation signal from the device, and a frequency tracking circuit (AFC circuit, frequency tracking circuit) that tracks the frequency of the received radio signal and outputs an oscillation frequency control signal corresponding to the frequency. Tracking means)
32, a reference frequency oscillator that oscillates a local oscillation signal having a frequency based on the oscillation frequency control signal from the AFC circuit 32, and 25 a carrier frequency based on the oscillation frequency control signal from the AFC circuit 32. An offset frequency judging circuit (offset frequency detecting means) 26 for judging the offset amount holds a correspondence relationship between the carrier frequency offset amount and the radio base station as shown in FIG. ,
Zone determining circuit (zone determining means) for determining the zone 11-i where the wireless mobile station 2 is located and the wireless base station 1-i.
It is.

The receiving means 41 is constituted by the antenna 21 and the receiver 22, and the demodulating means 42 is constituted by the demodulation circuit 31 and the reference frequency oscillator 24.

The offset frequencies f1 to fn of the carrier frequency are set within a range that the AFC circuit 32 of the radio mobile station 2 can follow.

Next, the operation will be described. Each wireless base station 1-i (i = 1,..., N) is connected to another wireless base station 1-i.
The multi-station simultaneous transmission is executed by offsetting the carrier frequency by a value different from j (i ≠ j). Wireless base station 1-1 to 1
The wireless signal transmitted from −n is received by the receiver 22 via the antenna 21 of the wireless mobile station 2. The received radio signal is demodulated by the demodulation circuit 31 of the modem 23,
The original data is output to another built-in circuit (not shown).

At this time, the AFC circuit 32 of the modem 23
Performs a tracking operation so that the frequency of the local oscillation signal of the reference frequency oscillator 24 becomes the same as the carrier frequency of the received radio signal, and supplies an oscillation frequency control signal to the reference frequency oscillator 24. This oscillation frequency control signal is also supplied to the offset frequency determination circuit 25. The offset frequency determination circuit 25 stores the oscillation frequency control signal before tracking the carrier frequency of the received wireless signal (that is, when the offset value is zero), and offsets the oscillation frequency control signal from the oscillation frequency control signal before and after tracking. The frequency is determined, and the data of the offset frequency is supplied to the zone determination circuit 26. The zone determination circuit 26 determines the radio base station 1-i and the zone 11-i corresponding to the offset frequency with reference to the table shown in FIG.

As described above, according to the first embodiment, each radio base station executes radio communication by offsetting the carrier frequency by a value different from the other radio base stations, and the radio mobile station transmits the received signal. Since the offset value of the carrier frequency is detected and the own zone is detected based on the detected offset value, it is possible to detect the zone where the wireless mobile station itself is located in a wireless communication system that performs multi-station simultaneous transmission. The effect that it can be obtained is obtained.

Further, according to the first embodiment, the radio mobile station performs the frequency tracking process on the carrier frequency of the received signal to detect the offset value.
Generally, an effect is obtained that the location zone can be detected with a simple configuration using an AFC circuit built in the wireless mobile station 2.

The radio mobile station 2 is mounted on a vehicle such as an automobile, and is carried by a user as a portable terminal device such as a PDA (Personal Data Assistant).

Further, in the wireless communication system shown in FIG. 1, there is one wireless mobile station 2, but a plurality of wireless mobile stations 2 may of course be provided.

[0023]

As described above, according to the present invention, each radio base station executes radio communication by offsetting the carrier frequency by a value different from that of the other radio base stations, and the radio mobile station transmits the received signal. Detect the carrier frequency offset value,
Since the own location zone is detected based on the detected offset value, there is an effect that the wireless mobile station itself can detect the location zone in a wireless communication system that performs multi-station simultaneous transmission.

Further, according to the present invention, since the radio mobile station detects the offset value by executing the frequency tracking process on the carrier frequency of the received signal, it is generally built in the radio mobile station. There is an effect that the location zone can be detected with a simple configuration using the AFC circuit.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a wireless communication system according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a wireless mobile station according to Embodiment 1 of the present invention.

FIG. 3 is a diagram illustrating an example of a correspondence relationship between a carrier frequency offset amount and a radio base station.

[Explanation of symbols]

1-1 to 1-n wireless base station, 2 wireless mobile stations, 25
Offset frequency detection circuit (offset frequency detection means), 26 zone determination circuit (zone determination means), 32
Frequency tracking circuit (AFC circuit, frequency tracking means), 4
1 receiving means, 42 demodulation means.

Claims (6)

[Claims] 1. A location zone detection method for detecting a location zone of a radio mobile station itself among zones of a plurality of radio base stations performing simultaneous multi-station transmission, wherein each radio base station has a different value from other radio base stations. Performing a radio communication by offsetting a carrier frequency, wherein the radio mobile station detects an offset value of a carrier frequency of a received signal, and detects its own zone based on the detected offset value. Detection method. 2. The location zone detection method according to claim 1, wherein the wireless mobile station detects an offset value by performing a frequency tracking process on a carrier frequency of a received signal. 3. A radio communication system for performing radio communication between a plurality of radio base stations performing simultaneous multi-station transmission and a radio mobile station, wherein each radio base station has a carrier having a different value from the other radio base stations. Performing wireless communication by offsetting a frequency, wherein the wireless mobile station detects an offset value of a carrier frequency of a received signal, and detects its own zone based on the detected offset value. system. 4. The radio communication system according to claim 3, wherein the radio mobile station detects an offset value by performing a frequency tracking process on a carrier frequency of the received signal. 5. A wireless mobile station that performs wireless communication with a plurality of wireless base stations that perform multi-station simultaneous transmission, wherein: a receiving unit that receives a wireless signal from the wireless base station; Demodulation means for demodulating the radio signal obtained into the original signal, an offset frequency detection means for detecting an offset value of a carrier frequency of a radio signal from the radio base station, and an offset value detected by the offset frequency detection means. And a zone determining means for detecting a zone where the mobile station is located based on the mobile station. 6. The wireless mobile station according to claim 5, further comprising frequency tracking means for performing frequency tracking processing on a carrier frequency of the wireless signal to detect an offset value.