JPH10164651A - Base station equipment for public phs - Google Patents

Abstract

PROBLEM TO BE SOLVED: To secure a communication traffic by increasing the efficiency of a frequency by avoiding the interference between the base station devices of a plurality of operators when the base station devices are installed closely to each other. SOLUTION: Base station devices 1 and 2 are closely housed in a housing box 3. A control section 8 connects an antenna 4 to a receiving section 7 by means of an antenna switch section 5, sets the frequency assigned to the operators of the base station device 2 in the receiving section 7 from a channel setting section 10 after reading out the frequency from an operator frequency table section 9, and informs the receiving section 7 of the identification code of the operator after reading out the code from a measurement parameter section 11. The receiving section 7 performs reception by using the assigned frequency, fetches the operator identification code of LCCH(long control channel) information from the received signal, and informs the control section 8 of the code after collating the code with above-mentioned code. The control section 8 generates a super frame pulse and a frame pulse and transmits the pulses to a transmitting section 6. On the other hand, when a maintenance monitoring device 13 sends a frame synchronizing command through an exchange 12 for public PHS, the base station device are synchronized to each other in a similar procedure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station apparatus for a public PHS (Personal Handy Phone System), and more particularly to a form in which base stations by a plurality of service providers are jointly installed on a traffic signal or the like. It is used in. More specifically, the present invention relates to a procedure for a certain carrier to synchronize between base station devices by means independent of another carrier when installing a base station device with improved frequency use efficiency.

[0002]

2. Description of the Related Art Conventionally, a base station apparatus for public PHS based on a digital cordless telephone is independently provided by a service provider in consideration of the transmission output of the base station apparatus and conditions of radio wave propagation. The installation place was secured. In recent years, a traffic signal installed at an intersection of roads as an installation location of a base station device has been a promising candidate for securing a service area. At this time, if multiple operators provide public PHS services in a certain area, the base station devices of the multiple operators must be the same from the viewpoint of using facilities efficiently and equally between operators. It is assumed to be installed in a storage box.

Here, each base station apparatus is generally operated by a different operator, and as described above, these base station apparatuses are installed very close to each other. Therefore, in order to effectively use the frequency provided for the public PHS, in order to avoid interference between the base station devices, a superframe (to be described later in detail) with another operator's base station device is used. It is considered effective to synchronize

[0004]

An example of a technique for achieving synchronization between base station apparatuses is disclosed in Japanese Patent Application No. 6-315003. This document discloses a method for realizing synchronization between a plurality of base station devices in a configuration in which a plurality of base station devices are connected to one PBX (private exchange). However, as described above, generally, a plurality of base station devices that need to be synchronized with each other belong to different operators, and exchanges to which the base station devices are connected generally differ. Therefore, in such a case, the method disclosed in the above-mentioned document cannot be applied.

By the way, as a common air interface for the public PHS, the standard of the second generation cordless telephone system by the Radio System Development Center has been established.
Specified in RCR STD-28. Where PH
In S, a wireless system is used between the base station device and the mobile station (user's terminal device), and the air interface defines the interface of this portion.

According to the above-mentioned standard, when using a communication channel, in order to avoid occurrence of interference due to allocating the same frequency to a plurality of base station apparatuses, it is necessary to determine whether or not there is interference at a time specified by the base station apparatus. Must be detected. However, as described above, in a form in which traffic signals and the like are shared, base station apparatuses are installed very close to each other, and if frame synchronization is not established between these base station apparatuses, another base station apparatus cannot be used for one frequency. Interference with a maximum of two channels among the channels of the base station apparatus may occur. If the frequency of interference increases, the traffic decreases.

[0007] A base station for public PHS is an ISD.
Public PH using N (Integrated Services Digital Network) line
Connected to the S exchange. Therefore, considering instantaneous interruptions and route changes in transmission lines, frame synchronization between base station apparatuses, even between base station apparatuses of the same carrier, requires special monitoring, control lines and equipment. It is economically disadvantageous, such as the need for a class. Further, it is not realistic to achieve the above-described frame synchronization between the base station apparatuses of a plurality of operators.

Further, as another method of achieving synchronization between base station apparatuses, a base station apparatus is used as a master, and a synchronization signal is transmitted from the master base station apparatus via a wired transmission line to other base station apparatuses. May be distributed,
It is still not realistic because there is a problem such as the need for standardization among the operators. The present invention has been made in view of the above points, and an object thereof is to provide a public PHS by a plurality of operators.
If the base station equipment is jointly installed at traffic lights, etc.,
It is an object of the present invention to provide a public PHS base station apparatus capable of avoiding interference between these base station apparatuses, increasing frequency use efficiency, and securing communication traffic.

[0009]

In order to solve the above-mentioned problems, the invention according to the first aspect is directed to a position where base stations independently operated by a plurality of operators can mutually obtain a sufficient reception electric field. Public PH in the form installed in close proximity to
In the S base station apparatus, a base station apparatus operated by another carrier detects timing of a super frame transmitted at a predetermined cycle on a control channel, and a timing detecting unit that synchronizes with a timing of the super frame. Timing setting means for setting the timing of its own superframe, and performing communication in accordance with the set timing.

According to a second aspect of the present invention, in the first aspect of the present invention, the reception electric field level exceeds a preset value in an unused communication channel, or
Synchronization monitoring means for detecting a state in which the rate of occurrence of a frame error in a communication channel in use exceeds a preset value, and, when the state is detected, the timing setting means And first control means for instructing resetting of timing.

According to a third aspect of the present invention, in the first or the second aspect of the present invention, a command detecting means for detecting that a synchronization command has been sent from an external device; And a second control unit for instructing the timing setting unit to reset the timing of the superframe. According to a fourth aspect of the present invention, in the second or third aspect, each of the control means immediately blocks an unused communication channel and sets the unused communication channel to a blocked state. On the other hand, when the use state of the channel is released, the channel is set to the closed state, and after all the communication channels are set to the closed state, resetting of the timing of the super frame is instructed.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a base station apparatus for public PHS according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a base station apparatus according to the embodiment and an exchange connected to the apparatus. In the figure, a base station apparatus 1 and a base station apparatus 2 are public PHS base station apparatuses having different operators. here,
The base station apparatus 1 is a base station apparatus according to the present invention having a function for synchronizing between base station apparatuses, while the base station apparatus 2 is a conventional base station apparatus operated by another operator. It is. The base station device 1 and the base station device 2 are installed in an accommodation box 3 arranged at a traffic light or the like.

Next, the configuration of the base station apparatus 1 will be described in detail. In FIG. 1, reference numeral 4 denotes an antenna, and an antenna switching unit 5 connects the antenna 4 to either a transmitting unit 6 or a receiving unit 7 described later. That is, the antenna switching unit 5 connects the antenna 4 to the transmitting unit 6 when transmission is performed from the base station device 1, and connects the antenna 4 to the receiving unit 7 when the base station device 1 performs reception.

Here, the radio channel of the public PHS handled by the transmitting unit 6 and the receiving unit 7 will be described. The base station apparatus 1, which is a base station for public PHS, employs a TDMA (Time Division Multiple Access) system as a digital radio access system and a TDD as a transmission system.
(Time-division duplex) method. That is, the transmission information and the reception information are alternately communicated at the same frequency and time-division multiplexed (TDMA-TDD).

[0015] More specifically, the radio channel is used by a plurality of users, and in a frame transmitted and received periodically, each frame is divided into a plurality of time slots, and each user uses a different time slot. .
And a downlink channel from the base station device to the mobile station;
In order to separate an uplink channel from a mobile station to a base station apparatus, the same frequency is separated by time.

As can be seen from FIG. 2, the frame length is 5
ms, one frame is composed of eight slots, the first four slots are allocated to transmission slots, and the last four slots are allocated to reception slots. Therefore, one slot becomes 5 ms / 8 = 625 μs, and
In a normal operation state, the transmitting unit 6 by the antenna switching unit 5
The switching of the connection between the control unit and the receiving unit 7 is performed at a period of 5 ms / 2 = 2.5 ms. This switching control is performed by the control unit 8.
This is done according to the control signal sent from. Further, of these transmission slots and reception slots, one of them is used as a control slot, and the remaining three slots are used as communication slots.

In general, a communication protocol includes a call connection phase and a communication phase. In the PHS, the former phase includes a link channel establishment phase for establishing a link in a wireless section, and a telephone service such as voice transmission or IS service.
It is separated into a service establishment phase for establishing a radio link for non-telephone services such as DN. Among them, in the link channel establishment phase, the base station apparatus or the terminal establishes a link by an LCCH (logical control channel) using a control slot.

And the super frame mentioned earlier is
This means the minimum period of the downlink LCCH group transmitted intermittently by the same base station device. That is, this superframe is composed of m intermittent transmission slots for every n frames, and in a public PHS, n = 20 and m = 12
Is set to That is, 20 frames (= 5 ms ×
In this case, m (= 12) intermittent transmission slots are sequentially transmitted in a period of 20 = 100 ms).

The transmitting section 6 manages a radio channel transmission process in the base station apparatus 1 in accordance with a timing signal transmitted from the control section 8 described later. In addition, the receiving unit 7 controls the receiving process of the wireless channel in the base station device 1 according to the set frequency. At this time, the receiving unit 7 also performs a process of monitoring a received electric field level and a monitoring of occurrence of an error in a received frame, as described in detail later. On the other hand, the control unit 8 supervises each unit of the base station device 1, and details of its function will be described in the description of the operation. The carrier frequency table 9 stores LCCH information assigned to another public PHS carrier and stores signal frequencies. In the present embodiment, the carrier frequency of the carrier of the base station apparatus 2 is used. Is stored.

The channel setting unit 10 sets the receiving frequency of the receiving unit 7 according to the frequency information sent from the control unit 8. The measurement parameter unit 11 stores a carrier identification code of another carrier corresponding to the base station device 2, and stores in advance a reception electric field level and a threshold of a reception frame error rate. The LCCH transmitted from each base station apparatus
The information includes a carrier identification code of a carrier corresponding to each of the base station devices. On the other hand, in FIG.
Reference numeral 12 denotes a public PHS exchange. Further, the maintenance monitoring devices 13 and 13 transmit frame synchronization commands to the base station devices 1 and 2 via the public PHS exchanges 12 and 12, respectively.

Next, a procedure for realizing synchronization between base stations in the public PHS base station having the above configuration will be described. FIG. 2 is a timing chart for explaining this procedure. In FIG.
-2 "is a transmission signal from the base station apparatus 2 operated by another carrier, and the LCCH information is 100 m
This indicates that the data is transmitted in s cycles. Also, "SF
The signals "P" and "FP" are a superframe pulse and a frame pulse, respectively, and the details thereof will be described later.

In FIG. 2, a signal represented by “CTX-1” indicates the transmission / reception timing of the base station device 1. Here, the portion shown by the solid line is the transmission timing of the LCCH information. On the other hand, the portions indicated by broken lines indicate the timing of a communication channel for three slots used for voice communication during transmission and the timing of a communication channel for four slots used for reception. Here, the LCCH information is 100 ms
Since the data is transmitted intermittently in a cycle, the LCCH information is not transmitted at the timing indicated by the broken line. further,
In the figure, portions represented by “CS-T” and “CS-R” are enlarged views of timings of time slot allocation on the transmission side and the reception side, respectively. In these, time slots B (1) to B (3) following the LCCH information indicate communication channels used for voice communication.

First, the control unit 8 controls the antenna switching unit 5 to connect the antenna 4 to the receiving unit 7 at the time of initial setting such as turning on the power of the base station apparatus 1, and maintains this state. Further, the control unit 8 reads the reception electric field level and the threshold of the error rate of the reception frame from the measurement parameter unit 11 and sends the thresholds to the reception unit 7 to set them.

Next, the control unit 8 reads out the frequency of the LCCH information allocated to the other carrier corresponding to the base station device 2 from the carrier frequency table unit 9 and receives it via the channel setting unit 10. Set to section 7. Next, the control unit 8 reads the carrier identification code of the other carrier corresponding to the base station device 2 from the measurement parameter unit 11, notifies the receiving unit 7, and instructs the receiving unit 7 to start synchronization by continuous reception.

Then, the receiving unit 7 switches the receiving frequency to the frequency specified by the channel setting unit 10 and converts the signal received via the antenna 4 and the antenna switching unit 5 into an LC
Extract CH information. Next, the receiving unit 7 extracts the extracted LCC.
The operator identification code is extracted from the H information, and it is checked whether the identification code matches the one stored in the measurement parameter unit 11 and sent to the receiving unit 7. In this way, when receiving section 7 captures the LCCH information transmitted by base station apparatus 2 at a period of 100 ms, superframe detection pulse SF indicating that the LCCH information has been detected is received.
P is transmitted to the control unit 8 via the line La (see FIG. 1). Thereby, the control unit 8 generates a superframe pulse SFP of its own base station apparatus 1 at a cycle of 100 ms based on the received superframe detection pulse SFP, and based on the pulse, the transmission / reception frame in the base station apparatus 1. A frame pulse FP serving as a timing is generated at a period of 5 ms. These pulses are transmitted to the transmission unit 6 via the line Lb in FIG.

As described above, the signal CTX-2 shown in FIG.
, A superframe detection pulse SFP is generated at a period of 100 ms on the base station apparatus 1 side in synchronization with the LCCH information included in the base station apparatus 1, and a frame pulse FP is generated at an interval of 5 ms in synchronization with the superframe detection pulse SFP. This means that frame synchronization has been achieved between the base station apparatuses. Thereafter, according to the generated transmission / reception timing, transmission / reception processing similar to the conventional one is performed.

Next, a description will be given of the monitoring control of the synchronization state performed in the operation state of the base station apparatus. In a normal operation state, the receiving unit 7 constantly monitors the reception electric field level in a slot not used for communication, and constantly monitors an error occurrence of a reception frame in a slot used for communication. Then, the receiving unit 7 determines whether the received electric field level exceeds the threshold value in an unused communication channel based on the received electric field level and the received frame error rate threshold value notified from the control unit 8 at the time of the initial setting, or When the occurrence rate of the frame error in the communication channel in use exceeds the threshold, the occurrence of interference is notified to the control unit 8.

Then, if the communication channel is unused, the control unit 8 immediately sets the communication channel to the closed state. On the other hand, if the communication channel is in use, the control unit 8 sets the communication channel in a pre-blocked state,
After that, when this communication channel becomes unused, the communication channel is closed. Then, when all the communication channels are blocked, the LCCH information included in the superframe transmitted by the base station apparatus 2 by another operator is detected by the same procedure as that performed at the time of the initial setting. Thus, the transmission timing in the transmission unit 6 and the reception timing in the reception unit 7 are adjusted. As described above, in the base station device 1 of the present embodiment, the monitoring and control of synchronization between the base station devices is performed autonomously in the operation state.

On the other hand, when a trouble such as a poor reception rate occurs, the maintenance monitoring device 13 issues a frame synchronization command to the public P.
The data is transmitted to the base station device 1 via the HS exchange 12. Then, the base station device 1 that has received the command performs a synchronization process between the base station devices in accordance with the same procedure as described above, and when the synchronization is completed, the base station device 1 sends a message to the maintenance monitoring device 13. To transmit a frame synchronization completion notification. As described above, in the base station apparatus 1 of the present embodiment, the synchronization between the base station apparatuses can be performed even by a command from a remote apparatus. Note that the present invention is not limited to the above description. For example, in the above embodiment, the case where two base station apparatuses are installed in the accommodation box 3 has been described, but it is needless to say that three or more base station apparatuses may be accommodated.

[0030]

As described above, according to the present invention,
A superframe transmitted from the base station device of another carrier is detected, and the timing of the superframe of the own base station device is set in synchronization with this timing to achieve synchronization. As a result, even when the base station apparatus is installed very close to the base station apparatus, the occurrence of frequency interference in a communication channel with another base station apparatus by means independent of the base station apparatus of another operator. This has the effect of minimizing power consumption, increasing the efficiency of equipment utilization, and enabling effective use of frequency.

According to the second aspect of the present invention, the superframe timing is reset when the reception electric field level exceeds a set value or when the occurrence rate of a frame error exceeds the set value. Therefore, even when these inconveniences occur, there is an effect that the synchronization between the base station devices can be autonomously re-established before the frequency of the interference of the communication channel increases.

According to the third aspect of the present invention, the timing of the superframe is reset by the synchronization command from the external device, so that the synchronization between the base station devices is appropriately controlled from outside. The effect of being able to do so is obtained. According to the fourth aspect of the invention, if the communication channel is not used, the communication channel is immediately closed, while if the communication channel is in use, the communication channel is closed when the use state is released. And synchronizing superframes can be performed as quickly as possible.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a public PHS base station apparatus according to an embodiment of the present invention and an exchange and the like connected to the base station apparatus.

FIG. 2 is a timing chart for explaining a synchronization procedure between base station devices according to the embodiment.

[Explanation of symbols]

 1, 2 base station apparatus 3 accommodation box 4 antenna 5 antenna switching section 6 transmitting section 7 receiving section 8 control section 9 carrier frequency table section 10 channel setting section 11 measurement parameter section 12 public PHS exchange 13 maintenance and monitoring device

Claims (4)

[Claims] 1. A public PHS base station apparatus in which base stations independently operated by a plurality of carriers are installed close to a position where a sufficient reception electric field can be obtained. Timing detecting means for detecting the timing of a superframe transmitted at a predetermined cycle on a control channel by the base station apparatus operated by the control unit; and timing setting for setting the timing of the superframe in synchronization with the timing of the superframe. Means for performing communication in accordance with the set timing. 2. A state in which a received electric field level exceeds a preset value in an unused communication channel or a frame error occurrence rate in a used communication channel exceeds a preset value is detected. And a first control unit that instructs the timing setting unit to reset the timing of the superframe when the state is detected. The base station apparatus for public PHS according to the above. 3. A command detecting means for detecting that a synchronization command has been sent from an external device, and when the command is detected, resetting the timing of the superframe to the timing setting means. The public PHS base station apparatus according to claim 1 or 2, further comprising a second control means for instructing. 4. Each of the control means immediately closes an unused communication channel and blocks the communication channel in use when the use state of the channel is released. The public PHS base station apparatus according to claim 2 or 3, wherein the channel is set in a closed state, and an instruction to reset the timing of the superframe is issued after all communication channels are set in a closed state.