JPH10191435A - Mobile object communication system, base station and mobile communication control station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the generation of the hit of a signal at the time of switching a base station by allowing plural base stations to transmit signals obtained by adding reliability information to the received signal to a mobile communication control station (MCC: mobile communication control center) and allowing the control station to select one of plural signals concerning the same connection in a handover state. SOLUTION: At MCC, an exchanging part 105 selects one receiving signal before/after exchange based on reliability information included in the received signal from among the plural received signal of the same mobile station 104-4 of a transmission source, which is given from plural base stations 103-1 and 103-2 received by interface parts 106-1 and 106-2. On the other hand, MCC 102 where a signal to a mobile station 104-2 in a handover state sends the signal by the function of the part 105 to plural base stations 103-1 and 103-2 by synchronizing as a signal to the same mobile station 104-2, and the mobile station 104-2 fetches the signal inside by largest rate composition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a base station, a mobile communication control station, and a mobile communication system, and more particularly, to preventing deterioration of communication quality at the time of handover.

[0002]

2. Description of the Related Art When a mobile station moves from a cell range of a certain base station to a cell range of an adjacent base station, a so-called handover process for switching a base station accommodating the mobile station occurs.

Conventionally, at the time of handover, a signal from a mobile station is transmitted from a base station of a handover source to a mobile communication control station (Mobile Communication Control Station) accommodating a plurality of base stations.
communication control center; hereinafter, referred to as MCC) is switched from the handover destination base station to the MCC, and the signal from the mobile station is transmitted to the MCC only through one of the base stations. It is made to be given.

[0004] Here, the base station of the handover source and the base station of the handover destination are configured to transmit signals synchronously under the control of the MCC, and to transmit a signal from a mobile station to the MCC. Is switched, the continuity of the signal from the mobile station reaching the MCC is ensured.

[0005]

By the way, conventionally, each base station and MCC have a GPS (Global Positioning System).
ng System) has a timer capable of measuring an absolute time using a receiver, and based on the measurement of such a timer, the MCC causes each base station to synchronously transmit a signal from a mobile station in a handover state. Therefore, even if the base station which supplies the signal from the mobile station to the MCC is switched from the handover source base station to the handover destination base station, the continuity of the signal from the mobile station reaching the MCC is almost guaranteed. I was

[0006] However, the configuration of the base station and the MCC has been large and complicated because of the provision of the GPS receiver.

Therefore, it is conceivable to apply a timer having a simple configuration as a timer of a base station (or MCC). However, in such a case, the timekeeping accuracy of the timer is lower than before, and there may be a difference in the timekeeping time between adjacent base stations, so that synchronous transmission is performed, and the MCC is transmitted from the handover source base station. Even if the state of transmission to the MCC is switched from the state of transmission to the MCC to the state of transmission to the MCC, a momentary interruption may occur in the signal of the mobile station reaching the MCC.

[0008] Such an instantaneous interruption does not hinder the call, but it still reduces the call quality.

Therefore, there is a demand for a base station, a mobile communication control station, and a mobile communication system capable of supplying a high-quality signal from a mobile station to a communication partner regardless of the type of a timer mounted on the base station or the MCC. .

[0010]

In order to solve the above-mentioned problems, a first aspect of the present invention is to provide a mobile station, a base station for communicating with the mobile station, and a mobile communication control system accommodating a plurality of base stations. In a mobile communication system having stations, each base station comprises:
When receiving a radio signal from a mobile station in a handover state, the mobile communication control station includes transmission means for adding reliability information on a radio channel to the received signal and transmitting the signal to a mobile communication control station, When a signal transmitted by the same mobile station in a handover state is received from a plurality of base stations, one reception signal to be provided to a transmission partner terminal based on reliability information included in each of the plurality of received signals. It is characterized by comprising selection means for selecting a signal.

Further, according to a second aspect of the present invention, when a base station that performs communication with a mobile station receives a radio signal from a mobile station in a handover state, the received signal has a reliability on a radio channel. Transmission means for adding information and transmitting the information to a mobile communication control station accommodating the self is provided.

Further, according to a third aspect of the present invention, in a mobile communication control station accommodating a plurality of base stations responsible for communication with a mobile station, the same mobile station in a handover state transmits from a plurality of base stations. When a signal is received, there is provided a selecting means for selecting one received signal to be provided to the transmission destination terminal based on the reliability information included in each of the plurality of received signals.

According to the first to third aspects of the present invention, a plurality of base stations which have received a radio signal from a mobile station in a handover state respectively transmit a signal obtained by adding reliability information to the received signal to a mobile communication control station. The mobile communication control station allows the mobile communication control station to select one from a plurality of signals related to the same connection in the handover state, thereby eliminating the need for mounting a high-precision timer as a timer for the mobile communication control station or the base station. Even when the base station is switched at the time of the handover, it is possible to prevent the instantaneous interruption of the signal from occurring.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a base station, a mobile communication control station and a mobile communication system according to the present invention will be described in detail with reference to the drawings.

FIG. 2 shows the configuration of the mobile communication system according to this embodiment. In FIG. 2, each base station 103-1, 103-2,...
Mobile stations 104-1, 10 existing within the range of AR2,.
4-2,... Are executed. These base stations 103-i (i is 1, 2,...) Are accommodated in a mobile communication control station (MCC) 102, and the MCC 10
2 and can be connected to the communication network 101.

Here, mobile station 104-j (j is 1, 2,
..) Moves from the cell range of one base station to the cell range of another base station due to the movement, a handover process for switching the base station as a communication partner of the mobile station is executed.

For example, in the case of FIG.
When the mobile station 10-2 moves from the cell range of the base station 103-1 to the cell range of another adjacent base station 103-2 due to the movement, the base station serving as the communication partner of the mobile station 104-2 is set as the base station. A handover process for switching from 103-1 to the base station 103-2 is executed.

This embodiment has a feature in the execution configuration of the handover process. FIG. 1 shows a conceptual signal flow at the time of handover in this embodiment, and the same reference numerals as those in FIG. 2 denote the same or corresponding parts.

In FIG. 1, a radio transmission signal from a mobile station 104-2 is transmitted to a plurality of base stations 10 at the time of handover.
3-1 and 103-2 are reached. In this embodiment,
Under the control of the MCC 102, the base stations 103-1 and 103-2 transmit the transmission signal from the mobile station 104-2 to the MCC 102 in synchronization (including the synchronization information in the signal). is there.

At this time, each of the base stations 103-1 and 103-2
Respectively, adds reliability information in a wireless channel to a transmission signal, and transmits the transmission signal to the MCC 102. In the MCC 102, the source mobile station 104-2 provided from the plurality of base stations 103-1 and 103-2 received by the interface units 106-1 and 106-2 is the same (that is, has the same connection). The switching unit 105 selects one of the received signals before or after the exchange based on the reliability information included in the received signal. One received signal selected in this way is transmitted to the communication partner terminal by the function of the switching unit 105.

On the other hand, the mobile station 10 in the handover state
In the MCC 102 having received the signal to 4-2, the function of the switching unit 105 (multicast function) divides the signal into a plurality of signals, and the interface unit 106-
1, 106-2, and a plurality of base stations 103-1 and 13-1.
03-2 and synchronously transmits the signal to the same mobile station 104-2. Thereby, each base station 103-1, 1
From 03-2, the same signal is given to the same mobile station 104-2, and the mobile station 104-2 combines the signals at the maximum ratio and fetches them inside.

Next, the configuration and operation of the MCC 102 of this embodiment will be described in detail with reference to FIG.

In FIG. 3, the MCC 102 includes a channel separating device 201, a channel multiplexing device 202, a time stamp adding device 203, a time stamp separating device 204,
Multicast device 205, handover memory table 206, route selection device (exchange switch) 207, 20
8, clock generation device 209, selection / synthesis device 210, channel multiplexing / clock insertion devices 211, 212,
It comprises channel separation / clock separation devices 213 and 24.

Next, the operation of the downlink (communication link to the mobile station) in the MCC 102 will be described.

The communication network 101 superimposes data of a plurality of connections between terminals (mobile stations, ordinary telephones, etc.) by time multiplexing and transmits the data to the MCC 102. The MCC 102 is connected to the communication network 101 and a synchronous digital hierarchy (synchronous hierarchy).
s Digital Hierarchy (hereinafter referred to as SDH). The transmission / exchange mode between the communication network 101 and the MCC 102 is an asynchronous transfer mode (Asynchronous Trans
fer Mode; hereinafter referred to as ATM) and synchronous transfer mode (Sy
nTM (hereinafter referred to as STM).

In the MCC 102, the time-multiplexed data is separated into respective channels in a channel separation device 201. A time stamp is added to the separated data in the time stamp adding device 203 for each fixed data amount.

For example, short cells are used in layering in which one ATM cell is shared by a plurality of communication connections. In the short cell, a sequence number is added to the same data amount for each connection. This sequence number is a time stamp (synchronization information)
It is realized as. The time stamp is reset at a cycle (for example, 10 ms) of a radio frame between the base station and the mobile station, and circulates. The radio frame cycle is a review cycle of signal selection at the time of handover described later.

In the channel separating device 201 and the time stamp adding device 203, the protocol of the data link layer of the external communication network 101 is terminated, and the protocol of the data link layer on the mobile communication system side is implemented.

The output data of the time stamp adding device 203 is input to the multicast device 205. Communication data between terminals (mobile stations) in the mobile communication system is looped back by the route selection device 207 and transmitted via the selection / synthesis device 210 in the same manner as the output data of the time stamp addition device 203, as described later. Are input to the multicast device 205.

The multicast device 205 recognizes the connection for performing the inter-cell handover by searching the handover memory table 206, performs data multicast for the corresponding connection, and sends each data to the route selection device 208. give. The route selection device 208 distributes the multicast data to a plurality of base stations involved in the inter-cell handover. Connection data not involved in inter-cell handover
The multicast is passed through the multicast device 205 without being multicast, and is provided to the route selection device 208 to select a route to the base station related to the destination mobile station.

Each channel multiplexing / clock inserting device 21
1, 212 receives data of one or more connections, multiplexes the data, and respectively receives the corresponding base station 103.
-1, 103-2. Here, a clock signal generated by the clock generation device 209 is inserted as a synchronization signal. For example, if the data rate is 1.544 Mbit
If it is s / s, a clock signal of 8 kbits / s is inserted.

The MCC 102 and each of the base stations 103-1 and 103-1
.. Are connected with an appropriate transmission line interface defined by SDH. MCC102
The transmission / exchange form between the base stations 103-1, 103-2,... May be any of ATM and STM. In this embodiment, ATM is mainly conscious.

Next, the operation of the uplink (communication link from the mobile station) in the MCC 102 will be described.

The multiplexed data transmitted from each of the base stations 103-1 and 103-2 is supplied to a corresponding clock separation / channel separation device 213 or 214, where the clock signal is separated. With synchronization, the multiplexed data is separated.

The data on the separated channel is input to the route selection device 207. The destination terminal of the data on the separated channel by the route selection device 207 is a terminal (mobile station) of the mobile communication system or the external communication network 1
01 is determined to be a terminal that needs to be connected via the mobile communication system, and if the terminal is a terminal (mobile station) of the mobile communication system, data on the separated channel is looped back,
Multicast device 205 via selective combining device 210
And if the terminal must be connected via the external communication network 101,
It is provided to the time stamp separator 204.

The selection / synthesizing device 210 stores the connection related to the handover in the handover memory table 206.
, And the selection of the received data at the time of performing the handover of the corresponding connection is performed for each radio frame,
A cell diversity effect has been obtained. For example, transmitted from the mobile station 104-2 in FIG.
, And 103-2, the two pieces of received data of the same connection given to the MCC 102 are narrowed down to one piece of received data by the selective combining device 210.

The time stamp separator 204 terminates the protocol in the mobile communication system (performs cell disassembly, etc.), and the channel multiplexer 202 is terminated so as to match the protocol of the external communication network 101. The data of each channel is multiplexed and transmitted to the communication network 101.

This embodiment, as described above, is transmitted from the mobile station 104-2 in FIG.
It is characterized in that a plurality of pieces of received data of the same connection provided to the MCC 102 via the first and second 103-2 are narrowed down to one piece of received data by the selection / combination device 210.

FIG. 3 shows an example in which a selection / synthesis device 210 is provided downstream of the route selection device (exchange switch) 207 to narrow down one piece of received data and send the data to the destination terminal as it is. The device 210 may be provided at the position shown in FIG. 4 or FIG.

FIG. 4 shows an example in which the selection / synthesis device 210 is provided in a stage preceding the route selection device (exchange switch) 207. That is, the MCC 10 transmitted from the mobile station 104-2 in FIG. 1 and transmitted through the plurality of base stations 103-1 and 103-2.
After the plurality of pieces of reception data of the same connection given to the second connection data are narrowed down to one piece of reception data by the selection / synthesis device 210, the route selection device 207 executes the route selection.

FIG. 5 shows an example in which the selecting / combining device 210 is provided as an outgoing-side trunk of a route selecting device (exchange switch) 207. That is, a plurality of pieces of reception data of the same connection transmitted from the mobile station 104-2 of FIG. 1 and given to the MCC 102 via the plurality of base stations 103-1 and 103-2 are transmitted through the route selection device 207. , And the data is narrowed down to one piece of received data, and then the received data is again provided to the route selecting device 207 to execute route selection according to the destination.

3-3 of the selective synthesizing device 210 shown in FIGS.
Although there are advantages and disadvantages in the types of installation methods, MC
Expandability due to the increase in the number of base stations accommodated by C102, and data (cells) reaching the communication partner terminal when the handover state changes from the non-handover state
Considering the order and the like, the installation method shown in FIG. 3 is considered to be the most practical.

FIG. 6 is a block diagram showing an example of the internal configuration of the selection / synthesis device 210. The internal configuration of the selection / synthesis device 210 can be represented by FIG. FIG. 6 shows MCC1
., The transmission / exchange mode between the base station 103 and each of the base stations 103-1, 103-2,... Is ATM.

In FIG. 6, the selection / synthesizing unit 210 has cell processing units 401 (401) for the number of input lines (M lines).
-1 to 401-M), the ATM cell buffers 402 (402-1 to 402-M) for the number of input lines, the selection unit 40
3 and a handover controller 404.

The cell processing unit 401 performs connection identification of a received ATM cell, identification of a short cell header, and the like, and provides such identification information to the handover controller 404. Further, the cell processing unit 401 gives the ATM cell that has been subjected to the above identification processing to the corresponding ATM cell buffer 402.

The ATM cell buffer 402 has a FIFO
(First-in first-out memory), and performs writing and reading of incoming ATM cells at timing specified by the handover controller 404.
It absorbs the fluctuation of the ATM cell flow of the same connection. The ATM cells read from the ATM cell buffer 402 are provided to the selection unit 403.

Under the control of the handover controller 404, the selection unit 403 passes the ATM cells from the ATM cell buffer 402 of the connection that is not in the handover state as it is, and transmits a plurality of ATM cells from the plurality of ATM cell buffers 402 of the connection that is in the handover state. ATM
It allows one of the cells to pass and discards the other ATM cells.

The handover controller 404 performs an interface function between a switch controller (not shown) and the handover memory table 206, writes information from the cell processing unit 401 into the handover memory table 206, and outputs information from the cell processing unit 401. It controls the ATM cell buffer 402 and the selection unit 403 based on the contents stored in the handover memory table 206 and the like.

In FIG. 3, since the functional blocks are represented by functional blocks such as the path selecting device 207, the selecting / combining device 210, and the time stamp separating device 204, it is assumed that the functional blocks have the elements, Although not described, there is a switch controller that controls the route selection device 207, the selection / synthesis device 210, the time stamp separation device 204, and the like.

The handover memory table 206 stores information required for processing at the time of handover under the control of the handover controller 404. The handover memory table 206 of this embodiment basically stores various information for each connection in a handover state. This stored information will be clarified in the following operation description.

FIGS. 7 to 9 are flowcharts showing the processing flow of the selection / synthesizing device 210 having the configuration as shown in FIG. In the flowcharts of FIGS. 7 to 9, the term “handover” is represented by “HO”.

When connection information to be handed over is provided to the handover controller 404 from a switch controller (not shown), the handover controller 404 stores the connection information in the handover memory table 206.
Information indicating that the connection is in a handover state is written (step 500). This process is actually executed in parallel with the following processes.

When an ATM cell arrives at the cell processing unit 401 (step 501), the corresponding ATM cell buffer 4
02 (step 502), and updating of the handover memory table 206 (steps 503 to 503).
509) is executed.

In the updating process of the handover memory table 206, first, it is determined whether or not the arrived ATM cell is related to the connection defined in the handover memory table 206 (connection in which connection information is written in the table 206). A determination is made (step 503).

If the cell is an ATM cell of a connection that is not defined in the table 206, the updating of the handover memory table 206 is terminated without updating the table 206 as a cell not to be subjected to handover (step 504) (step 509). .

On the other hand, if the ATM cell is a connection ATM cell defined in the handover memory table 206, the address of the ATM cell buffer 402 in which the cell is written is stored in the handover memory table 206 as an ATM cell to be handed over. Write (step 505). Here, the handover memory table 206
Has an area in which the address information of each of the ATM cell buffers 402-1,..., 402-M can be stored in association with the connection information. In the area,
Write the address where the ATM cell is stored.

Thereafter, the ATM cell that has arrived this time is a radio frame (a frame between the mobile station and the base station; for example, 1).
It is determined whether or not the ATM cell is the ATM cell at the head of (the cycle is 0 ms) (step 506). This decision is made by the ATM
This is performed based on the time stamp (sequence number) added to the cell.

If it is not the ATM cell related to the head of the radio frame, the updating process of the handover memory table 206 is ended without writing the reliability information and the radio frame head information in the handover memory table 206 (step 507). 509).

On the other hand, if the ATM cell is at the head of the radio frame, the handover memory table 20
6, the reliability information of the ATM cell arrived this time,
It writes that the ATM cell that has arrived this time is the head of the radio frame (step 508), and ends the update processing of the handover memory table 206 (step 50).
9).

It is to be noted that the following ATM after step 510 is used.
The reading process from the cell buffer 402 is executed in parallel with the writing process in step 502 described above, but is shown as a continuous process in FIGS. 7 to 9.

Each ATM cell buffer 402 cyclically reads data, including empty cells (step 510). By the write processing at the time of arrival of the above-described step 502 and the periodic and cyclic read processing,
Fluctuations in the ATM cell flow for the same connection can be absorbed. Therefore, it is not necessary to provide the fluctuation absorbing buffer outside the buffer in the selective combining device 210 (although it may be provided).

When one ATM cell is read from a certain ATM cell buffer 402, the handover memory table 2
On the basis of the stored contents of 06, it is determined whether or not the ATM cell is a cell for the connection to be handed over (steps 511 and 512).

If the cell is not an ATM cell for the connection to be handed over, the cell is passed through the selection unit 403 as it is and output from the selection / combination device 210 (step 528).

On the other hand, if the ATM cell is for a connection to be handed over, another ATM cell for the same connection (the content of the data body is read out based on the address information corresponding to the connection in the handover memory table 206). (Same as ATM cell)
Is stored in another ATM cell buffer 402 (step 513).

Here, unless another ATM cell having the same connection (and having the same time stamp) as the ATM cell related to the current read is not received (until the ATM cell related to the current read is read). (Step 514), and the selection unit 403 selects the ATM cell to be output (Step 527), and outputs it from the selection / combination device 210 (Step 527). Step 528).

On the other hand, if the same ATM cell as the ATM cell related to the current read has been received, the AT to be selectively combined is determined.
The M cell determination process is started (step 515), and the reliability information included in the plurality of ATM cells is recognized.
It is determined whether or not the reliability information is OK (step 516).

If there is no ATM cell for which the reliability information is OK, this is set (step 519), and it is determined whether or not there is valid selection information in the previous radio frame (step 520). ). If there is no valid selection information in the previous radio frame, it is determined that the ATM cell on the handover source side is to be selected from the plurality of ATM cells (step 521).
At the same time as selecting a cell, other ATM cells are discarded (step 527), and the selected ATM cell is output from the selective combining device 210 (step 528). If there is valid selection information in the previous radio frame, it is determined to select an ATM cell according to the logic determined by the selection information from the plurality of ATM cells (step 52).
2) The selection unit 403 selects the ATM cell, discards the other ATM cell (step 527), and outputs the selected ATM cell from the selection / combination device 210 (step 528).

If there is only one ATM cell whose reliability information is OK among a plurality of ATM cells related to the same connection, the fact is set (step 517), and then OK is performed.
(Step 5)
18) The selection unit 403 selects the ATM cell and discards other ATM cells (step 527),
The selected ATM cell is output from the selective combining device 210 (step 528).

If there is a plurality of ATM cells whose reliability information is OK among a plurality of ATM cells related to the same connection, after setting them (step 523), there is valid selection information in the previous radio frame. It is determined whether or not this is the case (step 520). If there is no valid selection information in the previous radio frame, it is determined to select the ATM cell on the handover source side from the plurality of ATM cells (step 525), and the selection unit 403 selects the ATM cell. At the same time, the other ATM cells are discarded (step 527), and the selected ATM cells are output from the selective combining device 210 (step 528). If there is valid selection information in the previous radio frame, multiple ATMs
ATM according to the logic determined by the selection information from cells
After deciding to select a cell (step 526),
The selection unit 403 selects the ATM cell, discards the other ATM cell (step 527), and outputs the selected ATM cell from the selection / combination device 210 (step 528).

As described above, the selective combining device 21
At 0, adjustment and selection of the ATM cell for the same connection in the handover state are executed in the radio frame period.

Next, the configuration and operation of the base station 103 of this embodiment will be described in detail with reference to FIG.

In FIG. 10, a base station 103 includes a clock separation / channel separation device 301, a channel multiplexing / clock insertion device 302, a time stamp separation device 303,
Clock synchronizer 304, time stamp adding device 30
5, frame configuration / offset correction device 306, frame period generation device 307, frame decomposition device 308, channel coding device 309, pilot coding device 310,
Channel decoding device 311, spreading modulation devices 312 and 3
13, rake receiver 314, carrier modulator 31
5. Carrier demodulation device 316 and antenna device 31
7.

Next, the operation of the downlink (communication link to the mobile station) in the base station 103 will be described.

Clock separation / channel separation device 301
Separates the multiplexed data transmitted from the MCC 102 into respective channels and separates a clock signal, further refers to the separated clock signal, and adjusts the clock signal inside the base station 103 to the separated clock signal. The clock synchronizer 304 is operated.

As the clock synchronizer 304, for example, a phase-locked loop (Phase-Locked LOOP; hereinafter,
PLL circuit). The PLL circuit 304 converts the clock signal of the base station 103 into the MCC 102
, But the phase difference is only a phase delay due to transmission, and has the same clock frequency and the same time can be calculated.

After the time stamp is separated from the data from the clock separation / channel separation device 301 by the time stamp separation device 303, the frame structure
The frame is supplied to the offset correction device 306, and the frame configuration / offset correction device 306 forms a frame that is a unit transmitted in a wireless section.

Note that the frame configuration / offset correction device 306 receives the radio channel propagation delay information from the handover source base station via the MCC 102 (this means that the base station is the handover destination base station). ), And an offset corresponding to the information is corrected to form a frame. This is because the handover source and the handover destination base stations are synchronized to allow the mobile station to perform radio transmission.

The data formed in the frame is subjected to error correction coding such as convolutional coding or interleaving in the channel coding device 309 (conscious of CDMA communication), and then spread by the spread modulation device 312. Spread to bandwidth. For example, the symbol rate after error correction 6
4.9 by spreading 4 ksymbols / s 64 times.
096 Mchip / s, that is, a signal with a spread band of 5 MHz.

On the other hand, the clock separation / channel separation device 3
The frame period is calculated by counting the clock signal separated from 01 in the frame period generation device 307, and the signal of this frame period is subjected to predetermined encoding in the pilot encoding device 310 to generate a pilot signal. You. This pilot signal is spread to a spreading band in spreading modulator 313.

The spread pilot signal and the spread user signal are added and combined with those of the other channels, modulated to a radio frequency by carrier modulation apparatus 315, and transmitted to mobile station 104 by antenna apparatus 317. .

Next, the operation of the uplink in the base station 103 (communication link from the mobile station) will be described.

A signal from one or a plurality of mobile stations 104 received by the antenna device 317 via the radio propagation path is demodulated into a spread band signal by the carrier demodulator 316 and provided to the rake receiver 314. The rake receiving apparatus 314 performs fading phase rotation correction, multipath synthesis, and despreading, and demodulates the signal into a baseband signal.

The baseband signal is subjected to error detection based on the CRC code inserted in the radio frame, error correction such as deinterleaving and Viterbi decoding by the channel decoding device 311, and the frame decomposing device 311 performs the error correction.
08, the radio frame is decomposed, and the radio interface is terminated.

The channel decoding device 311 transmits the signal from the base station to the mobile station, and accordingly, based on the time information of the control channel arriving at the base station from the mobile station,
It captures the propagation delay in the wireless link and forms information to be given to the handover destination base station.

In the case of this embodiment, the channel decoding device 311 outputs the error detection result (1 bit) using the CRC code.
Is added to the radio frame data as reliability information,
The frame disassembly device 308
In step 8, when the radio frame is disassembled (when the cell is assembled by disassembly), the reliability information is inserted into the head disassembled data (cell). As described above, this reliability information indicates that MC
In C102, it is used to determine selection from a plurality of data of the same connection.

The time stamp is added to the output data from the frame decomposing device 308 by the time stamp adding device 305 every predetermined unit of data. For example, when data is transmitted at a speed of 32 kbits / s, the predetermined unit is 1
In the case of ms, a time stamp is added for each 4-byte user data amount. This is also used by the MCC 102 to determine the synchronization data of the same connection.

The time-stamped data is multiplexed with other channels by the channel multiplexing / clock inserting device 302, and a clock signal is inserted into the data.
Sent to CC 102.

According to the above-described embodiment, a plurality of base stations that have received a radio signal from a mobile station in a handover state respectively transmit a signal obtained by adding reliability information to the received signal to the MCC. Since one is selected from a plurality of signals related to the same connection in the handover state, even if a high-precision timer is not installed as a timer of the MCC or the base station, the instantaneous signal may be changed when the base station is switched at the time of the handover. The occurrence of disconnection can be prevented.

The present invention is applicable regardless of whether the radio line is an analog line or a digital line. Further, the mobile station may be a mobile phone or a car phone. Further, the form of connection / exchange between the base station and the MCC does not matter.

Further, in the above embodiment, the reliability information used when selecting one from a plurality of signals related to the same connection in the handover state is a result of a CRC check on a radio frame. Other things may be used. For example, the reliability information may be formed using the result of estimating the propagation path characteristics of the wireless circuit.

Further, the detailed configuration of the selective synthesizing device 210 is not limited to that shown in FIG. For example, an ATM cell buffer may be provided in common for a plurality of input lines, and the handover memory table may be configured to manage the common buffer as a unit instead of a connection unit.

[0092]

As described above, according to the present invention, from a plurality of base stations receiving radio signals from a mobile station in a handover state, a signal obtained by adding reliability information to the received signal is used for mobile communication. A high-precision timer is installed as a timer for the mobile communication control station and the base station by allowing the control station to transmit and allowing the mobile communication control station to select one from multiple signals related to the same connection in the handover state Even without doing so, it is possible to prevent instantaneous interruption of the signal from occurring when the base station is switched at the time of handover.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a conceptual flow of a signal at the time of handover according to an embodiment.

FIG. 2 is a block diagram illustrating a configuration of a mobile communication system according to the embodiment.

FIG. 3 is a block diagram illustrating a configuration of an MCC according to the embodiment.

FIG. 4 is a block diagram illustrating a second installation method of the selective combining device according to the embodiment.

FIG. 5 is a block diagram illustrating a third installation method of the selective combining device according to the embodiment.

FIG. 6 is a block diagram illustrating a detailed configuration of a selective combining device according to the embodiment.

FIG. 7 is a processing flowchart (part 1) of the selection / synthesis device of the embodiment.

FIG. 8 is a flowchart (part 2) of the processing performed by the selection / synthesizing apparatus according to the embodiment;

FIG. 9 is a processing flowchart (part 3) of the selection / synthesis device of the embodiment.

FIG. 10 is a block diagram illustrating a detailed configuration of a base station according to the embodiment.

[Explanation of symbols]

101: communication network, 102: MCC (mobile communication control station),
103: base station, 104: mobile station, 207: route selecting device, 210: selective combining device.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Masato Onishi 1-7-12 Toranomon, Minato-ku, Tokyo Oki Electric Industry Co., Ltd.

Claims (8)

[Claims] 1. A mobile communication system comprising a mobile station, a base station for communicating with the mobile station, and a mobile communication control station accommodating a plurality of base stations, wherein each of the base stations is in a handover state. When receiving a radio signal from a mobile station located in the mobile communication control station, the mobile communication control station comprises: When a signal transmitted by the same mobile station in a handover state is received from a plurality of the base stations, one signal to be given to a transmission destination terminal based on reliability information included in each of the plurality of received signals. A mobile communication system comprising a selection unit for selecting a reception signal. 2. The received signal is divided into predetermined selection units, and the selection means includes:
2. The mobile communication system according to claim 1, wherein a process of selecting one received signal to be provided to a destination terminal is performed. 3. A base station which is in charge of communication with a mobile station, when receiving a radio signal from a mobile station in a handover state, adds reliability information on a radio channel to the received signal, and A base station comprising a transmitting means for transmitting to a mobile communication control station accommodating the. 4. A mobile communication control station accommodating a plurality of base stations responsible for communication with a mobile station, when receiving a signal transmitted by the same mobile station in a handover state from the plurality of base stations. A mobile communication control station comprising: a selection unit that selects one reception signal to be provided to a transmission destination terminal based on reliability information included in each of a plurality of reception signals. 5. The mobile communication control station according to claim 4, wherein said selection means is provided before a path switching means for switching a signal path toward a destination terminal. 6. The mobile communication control station according to claim 4, wherein said selection means is provided at a subsequent stage of a path switching means for switching a signal path toward a destination terminal. 7. The selection means is provided as an outgoing-side trunk of a path switching means for switching a signal path toward a destination terminal, and the selection means re-inputs a selected reception signal to the path switching means. The mobile communication control station according to claim 4, wherein the mobile communication control station is directed to a destination terminal. 8. The reception signal is divided into predetermined selection units, and the selection means includes:
The mobile communication control station according to any one of claims 4 to 7, wherein a selection process of one reception signal to be provided to a transmission partner terminal is performed.