WO2003086003A1

WO2003086003A1 - Timing controller and controlling method in radio network

Info

Publication number: WO2003086003A1
Application number: PCT/JP2002/003393
Authority: WO
Inventors: Eiji Ikeda; Tomonori Kumagai
Original assignee: Fujitsu Limited
Priority date: 2002-04-04
Filing date: 2002-04-04
Publication date: 2003-10-16
Also published as: JPWO2003086003A1; JP3821297B2

Abstract

A radio network controller, i.e. an IP node (1), sends a time stamp request message to a base station, i.e. an IP node (2), at a time of Tsend 1. The Tsend 1 is stored in the time stamp storage area at the originator of time stamp request message. Upon receiving the time stamp request message, the IP node (2) acquires the time Treceive 2 when that message is received and generates a time stamp response message. At a time Tsend 2, the time stamp response message is sent to the IP node (1). The Treceive 2 and the Tsend 2 are stored in the time stamp response message along with the Tsend 1. Upon receiving the time stamp response message, the IP node (1) calculates a transmission time from the IP node (1)to the IP node (2) and a transmission time from the IP node (2)to the IP node (1) based on the Tsend 1, Treceive 2 and Tsend 2 and uses them for timing control.

Description

Description: Timing control apparatus and method in wireless network

The present invention relates to a timing control apparatus and method between communication nodes in a digital bucket communication system using an IP protocol. Background art

In recent years, CDMA (Code Division Multiple Access) communication systems have been rapidly developed, and commercial services for narrowband CDMA communication systems have been implemented. Also, in order to exchange not only voice but also large data such as images, development of a system with a wider band (W-CDMA: Wideband-CDMA) is urgent. Under these circumstances, 3GPP (3rd Generation Partnership Project: http://www.3gpp.org/), which is a standardization organization for third-generation communication systems, suggests that specifications based on the W-CDMA system are being developed. The system has been developed and the introduction of the system specified in the 3GPP has begun.

Figure 1 shows an overview of the current 3GPP system.

Each node 101, 102-0: 102-n, 103-0 to 103_n, 104-0: L04-n is physically connected by an ATM (Asynchronous Transfer Mode) transmission line. Further, the exchange 101 and the core network 100 are physically connected by an ATM transmission line. In FIG. 1, a mobile station 105 transmits data to a plurality of base stations 103-0 to L03-n. After receiving this data, each of the base stations 103-0 to 103-n converts the data into an ATM cell and transmits it to the wireless network control device 102-0 via the ATM transmission line. Wireless network control equipment 1 In the case of 02-0, after processing these data, the data is converted into a replay ATM cell and transmitted to the exchange 101 via the ATM transmission line. Each of the wireless network controllers 102-0 to 102-n has a built-in protocol terminator and a controller for controlling the protocol terminator (see 3GPP Specification TS25.301 _S TS25.401, etc.). In addition, between the wireless network control devices 102-0 to L02-n and the exchange 101, between the wireless network control devices 102 to 102 to n, the wireless network control devices 102 to 102 to n and the base station 103. The interfaces between 0-; 103-n, 104- 0-: 104-n are called Iu, Iur, and Iub, respectively.

In the 3GPP system, the channels used for data transfer are specified for each protocol layer.

FIG. 2 is a diagram showing a typical protocol stack in a 3GPP system.

In FIG. 2, a channel for transmitting a signal in the RLC layer or higher is defined as a logical channel, and a channel for transmitting a signal in the MAC layer or higher is defined as a transport channel.

In 3GPP, the timing of signal transmission and reception is specified for each interface. Among them, Iub, which is the interface closest to radio, specifies the timing of signal transmission and reception in detail (TS25.402 , TS25.427, TS25.435) _D

In FIG. 2, the meaning of each abbreviation is as follows.

RRC: Radio Resource Control 3GPP document TS25.331 RLC: Radio Link Control 3GPP document TS25.322

MA C: Medium Access Control 3GPP document See TS25.321 FP: Frame Protocol 3GPP document See TS25.415, 425, 427, 435 AAL 2: ATM Adaptation Layer 2

ATM: Asynchronous Transfer Mode

PHY: Physical

RN L: Radio Network Layer

TN L: Transport Network Layer

Fig. 3 to Fig. 5 are diagrams explaining the synchronization acquisition procedure for signal transmission and reception in the 3GPP system.

In order to synchronize the timing between the radio network controller and the base station, a procedure called Node Synchronization is specified in 3GPP TS25.402 as shown in FIG. According to this, the wireless network control device SNRC and the base station No de B exchange timing between nodes by exchanging a control frame called DL Node Synchronisation ^ UL Node Synchronisation in which time information at each node is included. Is to be measured. Here, DL indicates downlink and UL indicates uplink. The two times (t2, t1 + t4-t3) indicate a round trip delay. 4094, 4095 '' of 31? ^ 〇-and 147, 148-■ of Node B indicate frame numbers, respectively.

On the other hand, on the transport channel on the Iub, each signal is assigned a connection synchronization number called CFN (Connection Frame Number), and this signal is transmitted and received according to a timing called TTI (Transmission Time Interval). It is carried out. In particular, the base station side has a reception window as shown in Fig. 4 for the received signal from the wireless network control device, and within this reception window, the signal having the expected CFN is contained. The normality of the transmission / reception timing is to be determined based on whether or not it has arrived. The signal sent by the wireless network controller arrives outside the reception window of the base station. In this case, the base station stores the timing deviation (ToA) in a control frame called iming Adjustment and sends it to the radio network controller. The radio network controller receiving the o Correct the signal transmission timing to the base station according to the value of A. Signals delayed at the base station are discarded.

In FIG. 4, TOA is ime Of Arrival (hereinafter simply referred to as arrival time in the description of the embodiment and others), LTOA is Latest Time Of Arrival, TO AWS is TOA Window Startpoint, TOA AWE is the TOA Window Endpoint, and t proc is the processing time before transmission to the radio. DL Data Frame 152 becomes OK when received in the reception window.

Therefore, as a precondition for performing the timing correction as described above, the CFN timings of the radio network controller and the base station must match each other. For this reason, after measuring the timing between the radio network controller and the base station by the above-mentioned Node Synchronization, the timing correction for CFN is performed for each transport channel of Iub by a procedure called Transport Channel Synchronization. Done. This is performed by exchanging control frames called DL Synchronization and UL Synchronisation that store reception timing information at the CFN and the base station on each transport channel, as shown in FIG. Since NodeB was able to receive the DL Data Frame with a difference between the end of the reception window and the TOA, the UL Data Frame can be correctly returned to the RNC. Frame Offset indicates the processing time of a frame within NodeB.

In FIG. 5, the abbreviations are as described above. In particular, the UE is a mobile station, and a DL Radio Frame and a UL Radio Frame are transmitted and received between the base station and the mobile station. As described above, the transmission timing on the I ub is strictly defined. In particular, for the downlink signal (signal from the radio network controller to the base station), the transmission timing on the radio and the base station have Precise timing control is needed because it greatly affects the amount of buffer to be used.

At present, in order to increase the affinity between the current 3GPP system and the existing Internet network, and to construct a flexible and cost-effective network, 3GPP's TNL protocol in the current system (see Fig. 2) Next-generation systems using the IP protocol group are being studied.

FIG. 6 is a diagram illustrating an example of a system using the IP protocol group as the TNL protocol.

In FIG. 6, a solid line indicates a physical path that is physically connected between nodes, and a dotted line indicates that nodes are logically connected via the Internet network or the like.

Note that 3GPP requires that the RNL in Fig. 2 does not significantly change the current system, so the functions implemented between nodes or between nodes are not Most will be carried over to next-generation systems.

Each of the wireless network control devices 601 to 603 and the base stations 604 to 608 can be directly connected to the Internet 600, respectively, and the nodes communicate with each other by the IP protocol group.

In the current system, the wireless network controller 102—102 to 102—n and the base station 103—103 to 103—n, 104—0 to 104—n are physically connected by an ATM transmission line. However, transmission time fluctuations are usually not a problem. However, for example, when the wireless network control device 601 and the base station 605 are connected via the Internet as shown in FIG. It is also conceivable that a signal is transmitted between nodes via a number of routers.In this case, due to a route failure or congestion, the transmission time between the radio network controller 61 and the base station 605 is reduced. It is considered that the fluctuation becomes very large.

A typical IP network is designed with a system design that focuses on network independence, flexibility, durability, simplicity, cost, etc., and requires complete timing control for all signals. Had not been. In other words, the design is based on the assumption that, even if a signal is delayed or lost due to a network failure or the like, it can be remedied by appropriate retransmission control in the upper layer. .

However, for systems that perform mobile communications, especially communications via radio, in addition to the characteristics of the IP network described above, in order to make effective use of the limited radio resources, strict It is necessary to guarantee a proper timing. In wireless communication, it is necessary to match the transmission and reception timings of the network side and mobile station side for all signals from normal traffic data to control signals. Naturally, wireless protocols have retransmission control, but unlike wired systems, in order to effectively utilize limited wireless resources, it is necessary to minimize unnecessary signal transmission and reception due to retransmission. In the current wireless system, it is possible to transmit and receive signals at a rate of up to about 38.4 kbps.In the near future, the rate will be about 2 Mbps, and in the future up to about 10 OM bps. The system is designed in the direction of improvement. If such retransmission occurs during such high-speed communication, a systemically fatal problem arises in that the effective rate cannot be increased simply by wasting radio resources. In addition, as a result of the accumulation of such states, it is possible that resources become insufficient and services cannot be performed.

Furthermore, in mobile communications, the mobile device continues communication while changing the transmission / reception position. For this purpose (handover), multiple radio channels (branches) must be established for one mobile device (mobile device 609 and base stations 604, 605 in Fig. 6). Unless the timing between branches is guaranteed, instantaneous interruption of communication or the like may occur when moving between areas, and communication quality may not be maintained, leading to call disconnection.

Based on the above, in the next-generation wireless system using the IP protocol, the timing control between nodes, especially on the Iub, which is the interface closest to wireless, is constantly performed, and the necessary timing control is performed in real time. There is a need to do. According to the timing control method on Iub in the current 3GPP system, it is possible to perform control that predicts timing deviation in advance. Whether or not to do this is left to the actual design. In systems that are already designed for pre-timing, changing the TNL protocol to the IP protocol may not be a big problem, but systems developed based on low-latency ATM technology. However, it is often the case that the timing control is not performed so frequently. In order to effectively utilize existing development assets and develop in a short period of time and low cost while developing such a system, the timing control function must be provided only in the lower layer (TNL). It is important to make it happen. Furthermore, if precise timing control becomes possible, the amount of buffers to be implemented by the base station can also be saved, and a low-cost system as a whole can be constructed. Disclosure of the invention

An object of the present invention is to provide an apparatus and a method for timing control when a wireless network control device and a base station are connected by an IP protocol in a wireless communication system. In particular, as described above, when a mobile communication system shifts from an ATM-based system with no transmission delay to an IP-based system with large transmission delay, the timing deviation when signals pass through the Internet is detected in advance.捕 Effective use of radio resources and improvement of the quality of radio communication (especially at the time of handover) are realized by preventing signal loss and signal loss 未 retransmission, etc. By using only the functions of the transport layer, and by reducing memory resources such as buffers, system development can be realized efficiently and at low cost in a short period of time. It is to provide price services.

The timing control device of the present invention is a wireless network control device in a wireless network in which a base station accommodating a mobile device and a wireless network control device for controlling a wireless network are connected by an IP protocol. A timing control device, comprising: a time stamp message storing a time stamp with a plurality of base stations; and a measuring means for measuring a round trip transmission time of a line connecting the base stations. Storage management means for storing and managing the measured transmission time in association with the base station, and control means for controlling the timing of transmitting a signal to each base station using the stored and managed transmission time. It is characterized by having.

The timing control method according to the present invention relates to a timing control method for a wireless network control device in a wireless network connected by a SIP protocol to a base station accommodating a mobile device, a wireless network control device for controlling a wireless network, and a wireless network control device. And transmitting and receiving a timestamp message containing a timestamp to and from a plurality of base stations, thereby measuring a transmission time of each round trip of a line connecting the base stations; and A storage management step of storing and managing the base station in association with the base station; and a control step of controlling a timing of transmitting a signal to each base station using the stored and managed transmission time. And

ADVANTAGE OF THE INVENTION According to the present invention, even if a base station and a radio network controller are configured by a network having a large fluctuation in transmission time, such as an IP network, the base station needs to communicate with a mobile device. Timing control can be easily performed. In particular, if each means is realized in the transport network layer of the 3GPP specifications, there is no need to change the upper layer, and the system development cost to conform to the 3GPP specifications can be reduced. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a diagram showing an overview of the current 3GPP system.

FIG. 2 is a diagram showing a typical protocol stack in a 3GPP system.

FIG. 3 is a diagram illustrating a procedure for acquiring synchronization of signal transmission and reception.

FIG. 4 is a diagram for explaining a procedure for acquiring synchronization of signal transmission and reception.

FIG. 5 is a diagram for explaining a procedure for acquiring synchronization of signal transmission and reception.

FIG. 6 is a diagram showing an example of a system using an IP protocol group as a TNL protocol.

FIG. 7 is a diagram showing an ICMP timestamp request Z response message format according to an embodiment of the present invention.

FIG. 8 is a diagram showing how a time stamp request response message is transmitted and received between IP node 1 and IP node 2 according to the present embodiment.

FIG. 9 is a diagram showing a state where the timestamp request / response message is stored in the payload of the IP bucket.

FIG. 10 is a diagram showing an embodiment of a signal termination unit in a wireless network control device for realizing the present invention. FIG. 11 is a diagram (part 1) illustrating a communication control sequence between the wireless network control device and the base station.

FIG. 12 is a diagram (part 2) illustrating a communication control sequence between the wireless network control device and the base station.

FIG. 13 is a diagram showing a configuration diagram of the transmission scheduling unit.

FIG. 14 is a diagram showing a configuration example of each table.

FIG. 15 is a diagram showing a configuration example of each table.

FIG. 16 is a diagram showing a configuration example of each table.

FIG. 17 is a diagram showing a processing flow when the wireless network control device is activated. FIG. 18 is a diagram depicting a processing flow for updating the inter-branch phase difference management table; FIG. 19 is a diagram showing a processing flow when transmitting a time stamp request message.

FIG. 20 is a diagram (part 1) illustrating a processing flow from updating of the transmission time management table to timing control.

FIG. 21 is a diagram (part 2) illustrating a process flow from the transmission time management table update to the timing control. BEST MODE FOR CARRYING OUT THE INVENTION

A system according to an embodiment of the present invention includes a radio network controller and a base station, each of which implements an Internet Protocol (IP) and an Internet Control Message Protocol (ICMP). In addition to a signal termination unit including a transmission / reception processing unit, a route control unit, an ICMP processing unit, etc., it further has a base station information management unit and an inter-branch phase difference management unit, based on information managed by these. Then, the timing control between the wireless network control device and the base station is realized by using the I CMP time stamp request / response message. This place In this case, the above 3GPP specifications shall be complied with.

The base station information management unit associates and manages the IP address of the base station, the transmission time between the radio network controller and the base station, and the like, and obtains a node obtained by the ICMP time stamp request response message. Timing control between the radio network controller and the base station is performed according to the inter-transmission time.

The inter-branch phase difference management unit dynamically updates, for each mobile device, the branch information according to the deletion of the additional tl ■ of the branch corresponding to the mobile device. In addition, the phase difference between branches is dynamically updated when data is received from the mobile station, and the timing control is triggered based on the updated phase difference between branches.

Further, all of the above functions are realized only by TNL functions.

FIG. 7 is a diagram showing an ICMP time stamp request / response message format.

The format of the time stamp request / response message in FIG. 7 is specified in IETRFFC950. In particular, in addition to the field indicating the message type, code, checksum, identifier, and sequence number, it has fields to store the source timestamp, reception timestamp, and transmission timestamp. The present embodiment is realized by using.

FIG. 8 is a diagram showing how a time stamp request / response message is transmitted and received between IP node 1 and IP node 2 according to the present embodiment.

In FIG. 8, the IP node 1 transmits a time stamp request message 800 to the IP node 2 at the time Tsendl. At this time, OxOD and time Tsendl are stored in the type code and source timestamp of the timestamp request message, and nothing is stored in the reception timestamp and transmission timestamp. Other fields store appropriate values. When the time stamp is received by the IP node 2 at the time Treceive2, the IP node 2 performs a receiving process, and then performs a receiving process. Then, the type code, the source time stamp, the reception time stamp, and the transmission time stamp of the time stamp response message 801 are received. In the amplifier, OxOE, Tsendl, Treceive2, and Tsend2 are stored, and the timestamp response message 801 is transmitted to the IP node 1 at time Tsend2. At this time, an appropriate value is stored in another area of the time stamp response message.

Then, when the time stamp response message is received by the IP node 1 at the time Treceivel, the IP node 1 calculates the transmission time 1 from the IP node 1 to the IP node 2 by Treceive2-Tsendl. Similarly, the transmission time 1 from the IP node 2 to the IP node 1 is calculated by T receive 1−T send 2.

The above timestamp request / response message is carried as the payload part of the IP bucket. Therefore, this message can be used for both IPv4 and IPv6.

An IP bucket header is added to the head of the IP bucket, and information (not shown) indicating from which part of the IP packet payload the I CMP timestamp request / response message is stored is stored. . Then, as shown in FIG. 9, the I CMP time stamp request / response message is stored in the payload of the IP packet and transferred. Therefore, when the wireless network controller and the base station are constructed with an IP network, time stamp information can be exchanged between the wireless network controller and the base station using such an IP bucket. .

The timing control method according to the embodiment of the present invention is a wireless network control device. An acquisition and management method of a transmission time between the radio network controller and the base station for guaranteeing a signal transmission / reception timing between the base station and the base station, and a timing control method,

(a) Initializing each table and setting initial information

(b) managing the IP address of the base station and the transmission time corresponding to the base station in a table

(c) Step of dynamically managing the phase difference between branches assigned to mobile devices for each mobile device using a table

(d) From a variety of information, a predetermined trigger is used to send an ICMP timestamp request message to the base station specified by the wireless network controller.

(e) calculating the transmission time from the time stamp response message received from the base station, and calculating the transmission time in the base station IP address management table in step (a).

(f) Step of controlling the transmission timing of the IP bucket for each base station based on the transmission time in the base station IP address management table described in step (a).

Further, such a timing control method between the radio network controller and the base station is based on a similar table for managing the IP address of the opposing radio network controller (connected by Iur in FIG. 6). By being provided in the control device, it is also applicable to timing control between wireless network control devices, that is, timing control on Iur shown in FIG.

Hereinafter, the configuration and processing steps of the present embodiment will be described in more detail. FIG. 10 is a diagram showing an embodiment of a signal termination unit in a wireless network control device for realizing the present invention. Figure 11 shows the wireless network controller and It is a figure showing the communication control sequence between base stations.

The meaning of each number in parentheses in FIG. 10 is as follows.

(1) Source IP address

(2) Received RNL data

(3) Receive I CMP data

(4) Destination IP address

(5) Transmission RNL data

(6) Transmission timing correction value

(7) Send I CMP data

(8) 1 CMP sending trigger

(9) Branch information phase difference information

(10) Phase difference information

(1 1) Timestamp request message transmission request

The signal termination unit is an IP datagram reception processing unit 1013, an IP datagram transmission processing unit 1000, a route control unit 1002, an RNL processing unit 1003, an ICMP processing unit 1010, a base station information management unit 1004, and an inter-branch location. It comprises a phase difference management unit 1007. The IP datagram reception processing unit 1013 receives the IP datagram, extracts necessary information from the IP datagram, and passes the information to each processing unit. The IP datagram transmission processing unit 1000 is a processing unit that transmits an IP datagram based on the processing result after the IP datagram is processed according to the information that the IP datagram had when it was input. The route control unit 1002 performs routing from the source IP address and notifies the IP datagram transmission processing unit 1000 of the destination IP address. The RNL processing unit 1003 performs RNL processing from the received RNL data, and inputs the result to the IP datagram transmission processing unit 1000 as transmission RNL data. The I CMP processing unit 10110 is a processing unit that performs timestamp response message processing and performs a timestamp request message processing, and internally includes a timestamp response message processing unit 1011, and a timestamp. It has a request message processing unit 101.

The base station information management unit 1004 has a control unit 1005 and a transmission time management table 1006 inside. The transmission time management table 1006 manages base station information for each entry. This management information can be of various types, for example, the IP address of the base station, a flag indicating whether the base station supports the ICMP, the reference radio network controller and the base station. The transmission time between them, the newly measured transmission time, the threshold used to compare the reference transmission time with the newly measured transmission time, etc. -Also, the control unit 1005 in the base station information management unit 1004 controls the information exchanged between the base station information management unit 1004 and other function blocks, and transmits Storing and retrieving information in the time management table, and setting for other function blocks.

The inter-branch phase difference management unit 1007 has a control unit 10◦8 and an inter-branch phase difference management table 1009 inside. The inter-branch phase difference management table 1009 manages, for each entry, branch information (plurality) set for the mobile station. There are various types of this management information.For example, when performing timing control based on a branch identifier for branch identification, phase difference information between a plurality of branches set in a single mobile station, and phase difference information This is threshold information used for the judgment criteria. The inter-branch phase difference management unit 1007 dynamically updates information in the inter-branch phase difference management table when adding or deleting a branch or acquiring an inter-branch phase difference at the time of data reception.

Note that the transmission scheduling unit 1001 that controls the transmission timing is based on the IP It is conceivable to incorporate it in the datagram transmission processing section 100.

The transmission scheduling unit 1001 in the IP data durum transmission processing unit 1001 controls the radio network control in order to absorb the transmission time difference (phase difference between branches) between the radio network controller and the base station. The transmission data from the device to each base station is transmitted after being buffered by the transmission scheduling unit for a certain period of time. That is, when a change occurs in the transmission time between the wireless network control device and the base station due to a network failure or the like, an appropriate transmission timing is corrected by adjusting the buffering time described above. It is. As a result, the timing can be corrected only by the IP layer independently of the upper layer.

The transmission scheduling unit 1 0 0 1

-Delay absorption buffer for buffering transmission data for a certain period of time-Delay time setting register that sets the time to buffer transmission data-In the delay absorption buffer based on the value stored in the delay time setting register Timing control unit that controls the transmission timing of the data

Consists of

When an error is detected in the transmission time between the wireless network controller and the base station by transmitting and receiving the time stamp request response message, the base station information management unit 1004 sends the corresponding information in FIG. Change the value of the CH delay time setting register. For example, if the transmission time to base station #A becomes much larger than normal (this judgment is made by comparing with the threshold (see Figs. 14 and 15)), Reduce the transmission data buffering time stored in the delay time setting register corresponding to A. Conversely, if the transmission time to base station #A becomes much shorter than normal, it is stored in the delay time setting register corresponding to base station A. Increase the transmission data buffering time.

If there is data to be transmitted, data transmission processing is performed according to the following procedure.

(1) The transmission data from the RNL processing unit 1003 is stored in the delay absorption buffer. At this time, it notifies the transmission timing control unit that the data has been stored.

(2) The route control unit 1002 notifies the IP processing unit of the destination IP address stored in the IP header. Upon receiving the notification, the IP processing unit immediately takes the data stored in (1) and generates an IP packet. The generated IP packet is stored again in the original delay absorption buffer.

(3) Upon receiving the notification in (1), the transmission timing control unit acquires the value stored in the corresponding delay time setting register, and after the delay time has elapsed, stores the value in (2). Send the IP bucket in the delayed absorption buffer.

Hereinafter, description will be made with reference to the sequences of FIGS. 11 and 12.

-Initialization of the transmission time management table at device startup

Normally, when the device starts up, the phase difference between the radio network controller and the base station is measured by the Node Synchronization procedure described above. At this time, the RNL processing unit 1003 compares the phase difference obtained by DL UL Node Synchronization with the corresponding base station in the transmission time management table 1006 in the base station information management unit 104. Set as an information element in the entry. By executing this procedure for all the base stations, the setting of all the reference transmission times in the transmission time management table 106 is completed and used for the subsequent timing control.

At the time of device startup, a time stamp request message is sent to all base stations set in the transmission time management table 106. This is not to measure the phase difference between nodes, but to check whether each base station supports the time stamp message. · At this time, the control unit 1005 in the base station information management unit 1004 sends a timestamp request message to the timestamp request message processing unit 1012 in the ICMP processing unit 1010. At the same time as issuing a transmission request, the base station obtains the IP address of the base station stored in the transmission time management table 1006, and sets it in the IP datagram transmission processing section 1000. Thereafter, IP datagram transmission processing section 1000 generates an IP datagram storing the time stamp request message, and transmits the IP datagram to the corresponding base station.

If the base station that received the time stamp request message does not support the time stamp request / response message (for example, if only the ICM PV 6 is installed), the base station controls the parameter error message by radio network control. Return to device. Since the wireless network control device that has received the parameter abnormality message knows that the base station that has transmitted the message cannot handle the time stamp message, it sets such information in the transmission time management table 106. By this procedure, the time stamp request message only needs to be sent to the base station that can handle the time stamp message thereafter. However, before the timestamp response message arrives, the parameter error message may be sent out for some other reason.In such a case, the timestamp request message must be sent again. Is desirable. In addition, base stations that are physically adjacent to the wireless network controller are less likely to have large transmission fluctuations as seen in normal IP networks. Can be set in advance not to send a time stamp message. As for system data such as a threshold, a predetermined value is set in the transmission time management table 106.

■ Initialization of the branch phase difference management table 1009 when the device is started

The contents of the inter-branch phase difference management table 1009 indicate when a call is set up. Information corresponding to the call is added to the entry, and when the call is released, the entry is deleted. Therefore, when the apparatus is started, all the contents of the inter-branch phase difference management table 1009 are initialized except for setting system parameters such as thresholds.

· Initialization of other function blocks at system startup

For other function blocks, perform appropriate initialization such as initializing storage means, initializing tables, and setting initial values.

• Procedure for setting the branch phase difference management table 1 0 9

As described above, the inter-branch phase difference management table 1009 is a table in which information is dynamically set and deleted when a call is set and released. Each entry in the table stores an ID number for identifying a mobile station and an ID of a branch assigned to the mobile station. At the time of handover or the like, a plurality of branches are allocated to one mobile device, so that a plurality of storage areas for the branch ID are also secured. This branch ID could use an IP address or could use a value that was uniquely mapped in the device. When multiple branches are allocated to one mobile station, the phase difference between the branches is calculated, and the calculated value is stored in the area in the corresponding entry. There are several methods for calculating this phase difference. For example, at the time of handover, the same data is duplicated in the mobile device and sent from each branch to the radio network controller. At this time, a method of setting the difference between the arrival times of the data arriving first and the data arriving latest as a phase difference in the table, and a method of setting an average value of the phase difference between the branches are conceivable. . When there is only one branch, it is necessary to perform processing to reduce the phase difference to zero.

When calculating the phase difference, it is necessary to keep the following points in mind. When a plurality of branches are set for a certain mobile station, the wireless network The network controller does not always receive the data for the number of branches from the mobile device, sometimes loses synchronization on the radio interface or on the Iub and loses the signal for a certain branch There is. In such a case, the radio network controller keeps data that should not arrive from the branch, and it is impossible to calculate the phase difference between branches accurately. In such a case, only the branch where the data arrives should be the target of the phase difference calculation. Therefore, in the inter-branch phase difference management table 1009, a threshold value for the arrival time is set for each mobile station, and the phase difference is set only for data arriving within the time specified by the threshold from the data arriving earliest. The method used for the calculation can be considered. The threshold value for the arrival time may be set in advance by system data. Also, the threshold value can be set to one for each device, not for each mobile device.

Further, when the radio network controller does not receive any data from a certain branch for a long time, for example, despite the disconnection of the call, the resources for the call remain without being released. It is expected that there is an abnormality in the radio resource management, such as that it is left standing. The accumulation of resources that are not released in this way eventually leads to a catastrophic state in which no service can be provided. Therefore, it is necessary to set a threshold for releasing resources and to forcibly release the resources if no data is received within the time indicated by the threshold. As before, the threshold may be provided for each mobile device, or one may be provided in the radio network controller.

As described above, various information related to the set branch is deleted from the template when the call is released.

■ Timestamp request message sending trigger

In this embodiment, a timestamp request message is transmitted at an appropriate timing. Then, the transmission time management table 1009 is updated from the information in the response message, and if necessary, timing control is performed to guarantee the transmission timing between nodes. Here, the trigger for sending the time stamp request message is described. First, as a first method, a method is conceivable in which a timer means is provided in the base station information management unit, and a time stamp request message is periodically transmitted by this means. At this time, a method is conceivable in which one timer is provided in the base station information management unit 1004, and when the timer times out, a time stamp request message is sent to all base stations all at once. . Alternatively, a timer is provided for each entry of the transmission time management table 1006 in the base station information management unit 104, that is, for each base station, and each independently transmits a time stamp request message periodically. A method is also conceivable. In the latter case, the transmission fluctuation is considered to be small for a base station that is close to the radio network controller, so the timer value is set relatively long, and conversely, for a base station that is far from the base station. Since the transmission fluctuation is considered to be large, it is possible to set a small timer value.

In a system in which an IP address is assigned to each branch and the branch is identified by the IP address, a method of transmitting a timestamp request / response message for each branch IP address is also possible. Control becomes possible.

In any case, these timer values may use predetermined values as system data, and new values are set each time a timeout occurs.

A second method is to send a timestamp request message when the phase difference between branches increases.

As described above, the information in the inter-branch phase difference management table 1009 is dynamically updated with the call setup and release, but the control unit in the inter-branch phase difference management unit 1007 Based on these real-time information, base station information management It is possible to give a trigger for sending a timestamp request message to the control unit 1004. The determination as to whether to give the trigger is made by comparing the inter-branch phase difference stored in the inter-branch phase difference management table 1009 with a certain threshold value. There are several possible treatments. For example, there is a method in which one threshold value is provided in the inter-branch phase difference management unit 1007, and all the phase differences corresponding to each mobile station are compared with the threshold value. Alternatively, a threshold value can be set for each entry, that is, for each call. In general, strict timing control is not always necessary for all services, and it is effective to perform timing control according to services.

In either method, when the phase difference between branches stored in the table becomes equal to or larger than the threshold value, the base station information management unit 1004 Request to send a timestamp request message to the server. At this time, it is necessary to send a timestamp request message to each base station to which the triggered branch belongs, but there are several ways to deal with this branch and the base station. As an example, if the branch is managed by IP address, the IP address of the branch and the base station should be the same as the subnet address, so this can be used for judgment. Alternatively, if the branch ID is assigned independently by the device, the information (IP address) of the base station may be provided in the mapping table, and the phase difference management unit 1007 for the inter-branch may be used. When giving the base station information management unit 1004 a trigger for the time stamp request message, the IP address of the base station itself should be set.

As a third method, when a timing abnormality is detected in the RNL processing unit 1003, that is, when the wireless network control device detects Timing Adjustment (refer to 3GPP Recommendation TS25.402), the trigger is used. I can think of a way You. In this case, the 1 1 3 processing unit 1003, upon receiving the iming Adjustment, sends an interrupt notification to the base station information management unit 1004, thereby triggering the transmission of the time stamp request message. It can be. Alternatively, a method is also conceivable in which the base station information management unit 104 periodically polls the RNL processing unit 1003 to detect whether or not a Timing Adjustment has been received. In addition, information for specifying which base station has transmitted the iming Adjustment is also required. This can be realized as follows. When receiving the data, the IP datagram reception processing unit 101 performs the processing of the IP layer to extract the RNL data. After that, the RNL data is passed to the RNL processing unit 1003, but the source IP address is used for route control and also passed to the base station information management unit 1004. The base station information management unit 104 that has received the transmission source IP address is held in the base station information management unit 104 until the reception of the iming adjustment is received. If the received data is normal data that is not Timing Adjustment, the IP address stored in the base station information management unit 104 is only overwritten when the next IP data is received. If it knows that the received data is an iming adjustment, it uses the held IP address as the timestamp destination.

■ Timestamp request message sending process

As described above, all the triggers of the time stamp request are collected by the base station information management unit 1004, and the base station information management unit 1004 that has detected the transmission trigger sends the ICMP processing unit 101 Requests the time stamp request message processing unit 1 0 1 2 within 0 to send a time stamp request message. At the same time, as described above, since the base station information management unit 1004 knows the IP address of the base station to which the time stamp request message should be sent, it sends the base station IP address to the IP datagram transmission process. Set to 100000. In addition, the time stamp request When receiving the trigger from the base station information management unit 104, the message processing unit 101 generates a time stamp request message and transfers it to the IP datagram transmission processing unit 100000. In this way, the timestamp request message and the destination IP address thereof are passed to the IP datagram transmission processing unit 1000, and the IP datagram transmission processing unit 1000 Generate and send.

■ Timestamp request message reception processing

The base station sends a timestamp response message in response to the timestamp request message sent by the wireless network controller, but describes the operation when the wireless network controller receives the timestamp response message.

After the IP datagram storing the time stamp response message is received by the IP datagram reception processing unit 103, if it is determined that the content of the IP datagram is an ICM The data is passed to the ICMP processing unit 10010, and the source address is also passed to the base station information management unit 1004 in addition to being used by the route control unit 1002. The ICMP processing unit 11010 receiving the ICMP data further processes the data in the timestamp response message processing unit 1011, if the data type is a timestamp response message. The time stamp response message processing unit 1011 calculates the transmission time between the radio network controller and the base station from the time information in the time stamp response message, and calculates the transmission time as the base station information management unit. Pass it to 1004. The base station information management unit 1004 includes: a source base station of the time stamp response message acquired from the IP datagram reception processing unit; and phase difference information acquired from the time stamp response message processing unit 101. And updates the phase difference information for the corresponding base station entry in the transmission time management table. -Timing control method

So far, a method for sending a timestamp request message and a method for extracting phase difference information between nodes from the received timestamp response message and updating the transmission time management table have been described. The method of actually performing timing control based on the information in the transmission time management table updated in real time is described below.

FIGS. 14 to 16 are diagrams showing configuration examples of each table.

As described above, the transmission time management table 1006 in the base station information management unit 1004 (see FIG. 14) compares the new and old phase differences held in the table, and A threshold is provided to determine whether to perform the timing control. When the transmission time management table is updated, the difference between the old phase difference and the new phase difference is calculated, and this value is compared with the threshold. In this case, for example, when a method of subtracting the old phase difference from the new phase difference is used as the difference calculation of the phase difference, the calculation result may naturally take both positive and negative values. Therefore, it is necessary to prepare at least two types of thresholds: the upper threshold (positive value) and the lower threshold (negative value). Alternatively, a method is also conceivable in which only one positive threshold is provided, and a negative threshold inverts the sign of the positive threshold. At this time, if the calculation result does not fall between the upper threshold value and the lower threshold value, it means that the phase difference has greatly deviated from the previous value, and thus the timing control is performed. Good. The IP datagram transmission processing unit 1000 has a transmission scheduling unit 1001 therein, which includes a phase difference between the radio network controller and each base station, and The timing offset for each transport channel is stored. Therefore, when performing the timing control, the control unit 1005 in the base station information management unit 1004 transmits the phase difference between the radio network control device in the transmission scheduling unit 1001 and the corresponding base station. By setting the corrected inter-node phase difference It is. Thereafter, a signal is transmitted to the base station on which the timing control has been performed, based on the detected phase difference.

FIG. 14 is a diagram illustrating an example of the embodiment of the transmission time management table.

For each entry, an area for storing the base station IP address, the ICMP flag, the reference transmission time Tbase, the measured transmission time Tnieasure, the upper and lower thresholds, and the transmission timer is provided.

The base station address indicates the IP address of the base station controlled by the radio network controller.

The I CMP flag is a flag indicating whether or not the base station supports the time stamp message, and is set according to the procedure at the time of starting the system described above. That is, when the base station returns a time stamp response message in response to the time stamp request message transmitted by the radio network controller,

If "Enable" is returned and a parameter error message is returned, set "Disable".

The reference transmission time T base stores the transmission time between the radio network controller and the base station obtained by Node Synchronization, which is also performed at system startup. This value is updated to a new value when timing control is actually performed.

The measured transmission time T measure stores the transmission time between the radio network controller and the base station, which is obtained by transmitting and receiving a time stamp message during system operation. This value is always compared to the reference transmission time.

The upper and lower threshold values are reference values when comparing the reference transmission time with the measured transmission time. As a comparison method here, timing control shall be performed when "lower threshold value (measured transmission time) one (reference transmission time) less than upper threshold value" is not satisfied. Also, the threshold is 1 per table, not per entry. It is also possible to provide three thresholds.

FIG. 15 shows another embodiment of the transmission time management table. In addition to the embodiment of FIG. 14, an upper threshold protection stage number and a lower threshold protection stage number are further provided. This is a method for not performing timing control immediately even if the difference between the measured transmission time and the reference transmission time exceeds a threshold. For example, if the transmission delay of a certain path increases instantaneously and then returns to the original state, useless timing control is not performed. In this embodiment, the number of protection steps is set at the time of table initialization, and the value is decremented by 1 each time the threshold value is exceeded, and timing control is performed only when the value becomes 0. . In Fig. 15, the number of protection steps for the upper threshold and the number of protection steps for the lower threshold are separately provided for each entry, but this is set as one protection step that combines the upper and lower limits, or for each entry, Instead, it is possible to provide one protection stage in the table. As described above, it is possible to set one threshold value in the table instead of the threshold value for each entry. FIG. 16 is a diagram showing an embodiment of the inter-branch phase difference management table. For each entry, an area for storing the mobile device ID, branch ID # 0 to n, the maximum phase difference between branches, and the threshold value is provided. At startup, this table has nothing stored (0 entries) and is set up only when a call is set up and a branch is set up for that call. When the call is released, the entry for the call is deleted. The branch information shall always be updated by appropriate means.

The inter-branch phase difference storage area is set based on the phase difference information between the branches obtained from the RNL processing unit 1003. Here, the maximum phase difference between a plurality of branches is set. Also, the phase difference is always compared with a value stored in a threshold storage area in the same entry, and when the phase difference is exceeded, the base station information management unit 1 A trigger can be triggered to send a timestamp request message to 004.

Here, too, the threshold value can be set to one protection level in the table instead of each entry.

■ Processing flow

Hereinafter, the flow of processing in the above embodiment will be described. FIG. 17 is a diagram showing a processing flow when the wireless network control device is activated. When the wireless network control device is started in S14-1, the various tables, storage means, etc. are initialized in S144-2, and the hardware initialization setting and application loading are performed. Various settings are made. Then, in S14-4, the platform or application acquires the system data, and stores the IP address of the base station, the threshold value corresponding to the base station, the number of protection steps, and the timer value in the transmission time management table 106. Set as many as the number of base stations. When this setting is completed, the Node Synchronization procedure is executed for all base stations by the RNL processing unit 1003, and the resulting transmission time between the radio network controller and each base station is calculated. It is stored as the value of the reference transmission time Tbase in the transmission time management table 1006 (S14_4). When the Node Synchronization is completed, in S14-5, the timestamp request message processing unit 101 in the ICMP processing unit 11010 and the base station information management unit 1004 cooperate, A time stamp request message is sent to each base station. Upon receiving the response message of the message, the ICMP processing unit 11010 identifies and determines the response message in S14-6, and if the response message is not a time stamp response message (for example, the parameter In S14-8, the base station that has returned the message determines that it cannot handle the time stamp message, and determines that the ICMP in the corresponding base station entry in the transmission management table 106 is not available. Flag It requests the base station information management unit 1004 to set it to Disable (this request is processed by the control unit 1005, etc.). On the other hand, if the response message is a time stamp response message in S14-6, the base station that has returned the message determines that the time stamp message can be received, and the The unit 11010 requests the base station information management unit 1004 to set the I CMP flag in the corresponding base station entry in the transmission management table 1006 to Enable. Further, at this time, the processing of the time stamp response message is transferred to the time stamp response message processing section 101, where the transmission time between the wireless network control device and the base station that has returned the message is calculated. It is. The transmission time calculated in this way is passed from the time stamp response message processing unit 101 to the base station information management unit 104 in S14-9, and the calculated value is transmitted to the transmission management unit. It is stored in Tmeasure in the corresponding base station entry in Table 106. The transmission / reception of the time stamp message and the calculation of the transmission time as described above are performed for all the base stations, and the initialization is completed (S14-10).

FIG. 18 is a diagram depicting a processing flow for updating the inter-branch phase difference management table; The inter-branch phase difference management unit 1007 performs a process of updating the information of the inter-branch phase difference management table 1009 and a process of monitoring the information in the table and triggering the transmission of a time stamp request message. Done. The former process is performed in cooperation with the RNL processing unit 1003, and the latter process is performed in cooperation with the time stamp request message processing unit 101 in the ICMP processing unit 110.

First, the processing flow when a branch ID is added to the left branch inter-branch phase difference management table 109 in FIG.

When a new branch is set by the RNL processing unit 1003 (S15-1), the setting information is passed from the RNL processing unit 1003 to the inter-branch phase difference management unit 1007. Is done. At this time, there are two cases: a case where a branch is set in accordance with the setting of a new call, and a case where a new branch is set for an existing call. Accordingly, the inter-branch phase difference management unit 1007 determines whether the mobile station corresponding to the newly set branch already exists as an entry in the inter-branch phase difference management table 1009 in S15-2. (S 15-2). Here, if the mobile station corresponding to the branch does not exist in the entry, in step S15-4 and S15-5, the mobile station determines the phase difference between the branches together with the branch information. It is newly registered in the management table 1009. On the other hand, if the mobile device corresponding to the branch has already been registered in the table in S15-2, a branch having the same branch ID as the branch in the entry of the mobile device in S15-3 To see if it already exists. If it exists, it means that the same branch is duplicated for the same mobile station, and an error response is returned to the upper-level processing unit in S15-8. If it does not exist, it is registered in the tuple as a newly set branch for the mobile station in S15-5.

Next, a processing flow when a branch ID is deleted from the right inter-branch phase difference management table 1009 in FIG. When the known branch is deleted by the length 1 ^ 1 ^ processing unit 1003 (S15-6), the deletion information is passed from the RNL processing unit 10 • 3 to the inter-branch phase difference management unit 1007. At this time, the inter-branch phase difference management section 1 • 07 checks whether the branch to be deleted is indeed already entered in the inter-branch phase difference management table (S15-7). If the entry is not in the table, if the instruction is to delete a branch existing in the entry, the branch is deleted in S15-9.

Finally, the message is sent from the same mobile station shown in Fig. 2 (b) via multiple branches. This section describes the processing when the wireless network control device receives the same data.

The inter-branch phase difference management unit 1007 constantly monitors the reception processing in the RNL processing unit 1003, and upon receiving uplink data from the mobile station (S15-10), the data is transmitted. Is stored in the primary storage area internally (S15—11). This reception time acquisition process is performed for each branch of each mobile device, so that the phase difference between branches is calculated for each mobile device, and the phase difference between branches is stored in the entry of the corresponding mobile device in the inter-branch phase difference management table 1009. Is set in the inter-branch phase difference storage area (S15-1-2). This calculation method includes, for example, taking the difference between the reception time of the earliest data and the reception time of the latest data. The phase difference calculated in this way is compared with the threshold value in the table in S15-13, and if it is larger than the threshold value, all base stations to which the branch assigned to the mobile station belongs Trigger the base station information management unit to send a timestamp request message to the base station (S15-14). At this time, the inter-branch phase difference management unit 1007 only needs to pass only the branch ID of the branch to the base station information management unit 104, and the base station information management unit 1004 By comparing the branch ID with the IP address of the base station in the transmission time management table 1006, it is possible to identify to which base station the branch belongs. Of course, other methods of determining the correspondence between the branch ID and the base station to which it belongs are conceivable and are not limited to this method. If the calculated phase difference is within the threshold value in the table in S15-13, the process returns to S15-10 to repeat the above processing.

FIG. 19 is a diagram showing a processing flow when transmitting a time stamp request message.

In the present embodiment, when a timing stamp request message is transmitted and the phase difference between the nodes needs to be re-examined, the triggers are all based on the base station information. It is collected in the management unit 1004. Thereafter, the base station information management unit 1004 that has received the trigger issues a message transmission request directly to the time stamp request message processing unit 101 in the ICMP processing unit 11010. The reason why the transmission trigger is collected in the base station information management unit 1004 is that the IP address of the base station to which the time stamp request message is sent is transmitted by the transmission time management table in the management unit 1004. This is to control which base station should send the timestamp request message for each trigger. In the present embodiment, the transmission trigger of the time stamp request message includes (1) transmission when an iming Adjustment is received, (2) transmission at a fixed period, and (3) when the phase difference between branches becomes large. Three types are possible. In particular, if an abnormality is detected in the signal transmission / reception timing as in (1) or (3), immediately confirm the normality between the wireless network controller and the base station using a time stamp message. Becomes important.

The actual processing flow is described below. When the imling adjustment is detected by the RNL processing unit 1003 (S16-1), the information is transmitted to the base station information management unit 1

It is passed to 004 as a timestamp request message sending trigger. At this time, at the same time, the IP address of the transmission source is passed from the IP datagram reception processing unit 101 to the base station information management unit 1004, so that the base station information management unit 1004

The IP address of the base station that sent the Timing Adjustment from the 1P address is determined (S16-2). Thereafter, in S 16-7, the base station information management unit 10

004 sends a timestamp request message sending request to the timestamp request message processing unit 101. Upon receiving the request, the time stamp request message processing unit 101, immediately generates a time stamp request message, and passes the message to the IP datagram transmission processing unit (S16-8). Also, the base station information management unit 1004 sends the IP datagram transmission processing unit 1004 To set the destination IP address determined in S16-2 (S16-9). In S16-10, the IP datagram transmission processing unit 1000 generates an IP datagram using the timestamp request message received in S16-8 and S16-19 and the destination IP address, and sends the IP datagram to the base station. And send it out.

Further, as shown in S16-3, when the trigger is periodically triggered by the time out of the transmission timer in the transmission time management table 1006, the base station corresponding to the expired timer is transmitted in S16-4. A timestamp request message is sent by the processing from S16-7 to S16-10 as described above, using the IP address of the IP address. Further, when the trigger is activated from the phase difference between the branches as shown in S15-10 to S15-14 in FIG. 18, the trigger is recognized in S16-5 and the branch is executed as described above. The base station IP address is determined from the ID (S16-6). After that, the time stamp request message is transmitted by the processing from S16-7 to S316-10 as described above.

FIG. 20 and FIG. 21 are diagrams illustrating a processing flow from updating of the transmission time management table to timing control.

In step S17-1, when an IP datagram is received, in step S17-2, the IP datagram reception processing unit 1013 performs an IP datagram reception process and an error check. If such an error is detected, error processing is performed in S17-3. If the IP datagram is normal in S 17-2, it is determined in S17-4 whether the payload of the IP datagram is an I CMP message. In step S17-5, normal IP bucket processing is performed. If the message is an I CMP message in S17-4, the ICMp message part is passed from the Ip datagram reception processing unit 1013 to the ICMP processing unit 1010, and a checksum and the like are sent in S17-6. I CMP messages Is checked for normality, and if an error is found, error processing is performed in S17-7. If the I CMP message is normal in S17-6, the type field in the I CMP message is checked in S17-8, and the message is an I CMP time stamp response message. Check if it is.

Here, if the I CMP message is not a time stamp response message in S 17-8, the normal I CMP message processing is performed by the I CMP processing unit 1010 in S 17-9.

On the other hand, if the message is a time stamp response message, the time stamp response message portion is passed to the time stamp response message processing unit 1011, and in S17-10, the time stamp response message processing unit The source time stamp, the reception time stamp, and the transmission time stamp are extracted from the time stamp response message, and the transmission time between the radio network controller and the base station is calculated. At this time, the base station information management unit 1004 stores a value in T measure in the entry of the pertinent base station in the IP datagram reception processing unit 1006 (S17-11). Then, in S17-12, for the entry updated in S17-11 in the transmission time management table 1006, the difference between the updated transmission time (Tmeasure) and the reference transmission time (Tbase) is calculated. The calculated transmission time difference is calculated in S 17-13 and compared with the upper threshold and the lower threshold in the same entry.

Here, if the difference between the transmission times is equal to or greater than the lower threshold and equal to or less than the upper threshold, there is no need to perform timing correction, and the process ends in S17-18 and the next IP datagram is deleted. Wait for reception. On the other hand, if the difference between the transmission times is equal to or less than the lower threshold value or equal to or greater than the upper threshold value in S17-13, the lower threshold is set in S17-14 if the difference exceeds the lower threshold. If the number of protection steps exceeds the upper threshold, Reduce the number of protection steps of the upper threshold by one. Then, in S 17-15, it is checked whether the number of protection steps directly above the upper threshold or the lower protection step is 0, and if not, the process ends in S 17 — 18.

On the other hand, if the number of protection stages becomes 0 in S17-15, it can be determined that the transmission time between the wireless network control device and the base station has deviated from the original one, It is necessary to correct the timing when sending data from the network controller. Accordingly, in S 17 _ 16, the base station information management unit 1004 sends the IP address of the base station to be corrected and the correction value (for example, T measure) to the transmission scheduling unit 1001. — Pass T base (the sign is the opposite of the difference in transmission time since it is a correction value)) and request that the timing be corrected. Thereafter, in S 17-17, the transmission scheduling unit changes the transmission timing offset for the base station specified by the base station information management unit by the correction value. As described above, the transmission timing is controlled.

As mentioned above, mobile communication systems will shift from ATM systems with low transmission delays and high costs to IP-based systems with high transmission delays and low costs according to the standard specifications defined by the 3GPP. The possibilities are becoming very high. In particular, for wireless communications that require strict timing control, it is expected that IP networks, which are usually said to be highly flexible, will increase transmission fluctuations and make it difficult to guarantee timing as a result. Under such conditions, for example, in the case of a handover technology that characterizes wireless communication, timing may not be guaranteed between a plurality of branches set in a certain mobile device, so that even its function cannot be satisfied. In addition, retransmissions due to delays occur frequently, and as a result, not only waste radio resources, but also retransmission of such signals leads to a significant decrease in the effective transmission rate, and will be further increased in the future. A big barrier to the demand for high-speed wireless communication I will. However, this is not the case if large-scale system changes such as mounting large-capacity buffers on each node and making changes to the existing control procedures are required for precise timing control. In terms of time and cost, there is no point in migrating existing systems to IP network systems.

According to the present invention, it is possible to realize timing control using only the functions below the transport network layer, that is, the IP layer, and it is not necessary to change the radio protocol layer (RNL) that controls the main function of radio communication. . As a result, existing development assets can be used effectively, and as a result, development time can be shortened and development costs can be reduced.

The timing control method described above not only measures the phase difference between nodes periodically, but also dynamically reflects the phase difference information between branches set for a certain mobile device. By doing so, it is possible to ensure a high level of signal transmission and reception during communication, especially at the time of handover. Of course, retransmission of signals can be minimized, and very efficient high-speed communication becomes possible from the viewpoint of radio resources.

Furthermore, since transmission fluctuations between nodes are monitored in real time, even if an error is detected even if it does not cause the signal to be discarded, it is corrected to the optimal timing in advance. As a result, the amount of reception buffer that the base station should have is kept to a minimum, which brings advantages such as miniaturization of equipment and cost reduction. In a normal wireless system, since a large number of base stations are installed, a reduction in the cost per unit greatly contributes to a reduction in the cost of the entire system, and therefore the impact is large. Industrial applicability As described above, according to the present invention, a high-quality and efficient system will be realized in a short period of time and at low cost even in the case of performing large-capacity wireless communication in an IP network with large transmission fluctuations in the future. As a result, services can be provided at low prices.

Claims

The scope of the claims

1. A radio network controller timing controller in a radio network in which a base station accommodating a mobile device and a radio network controller controlling a radio network are connected by an IP protocol,

Measuring means for measuring the transmission time of each round trip of a line connecting the base stations by exchanging a time stamp message storing the time stamp with a plurality of base stations;

Storage management means for storing and managing the measured transmission time in association with the base station, and control means for controlling the timing of signal transmission to each base station using the stored and managed transmission time. ,

A timing control device for dynamically performing timing control.

2. The timing control device according to claim 1, wherein the wireless network complies with specifications defined by 3GPP.

3. The timing control device according to claim 2, wherein each of the means is realized in a transport network layer.

4. The timing control device according to claim 1, wherein the time stamp message is a time stamp request / response message of an Internet control message protocol.

5. The storage management means stores the previously measured transmission time, the currently measured transmission time, the upper threshold and the lower threshold, and stores the previously measured transmission time and the currently measured transmission time. 2. The timing control device according to claim 1, wherein the timing control is performed when a difference between the transmission times falls outside the upper / lower threshold range.

6. The timing control device according to claim 5, wherein the timing control is performed when the difference between the transmission times falls outside the upper and lower threshold range by a predetermined number of times or more.

7. The timing control device according to claim 6, wherein the predetermined number of times can set different values for an upper threshold and a lower threshold.

8. The timing control device according to claim 1, wherein the time stamp message is periodically transmitted at predetermined time intervals.

9. The timing control device according to claim 1, wherein the time stamp message is transmitted when a message requesting message transmission from the base station is received.

10. The timing control device according to claim 1, wherein the time stamp message is transmitted only to a base station that can handle the time stamp message.

11. The apparatus according to claim 10, wherein a time stamp message is transmitted to each base station, and whether or not the base station can handle the time stamp message is determined based on a response content returned. Timing control device.

1 2. At the time of handover of the mobile station using the time stamp message Further comprising handover means for measuring and managing the phase difference between the plurality of branches for each mobile device, and controlling the timing of transmitting a signal from the wireless network control device based on the measurement result. 2. The timing control device according to 1.

13. The timing control according to claim 12, wherein the storage management means stores at least a mobile device identifier, a branch identifier, an inter-branch phase difference, and a threshold value for comparison with the inter-branch phase difference. apparatus.

14. The timing control according to claim 12, wherein the time stamp message is transmitted when a phase difference between a plurality of branches set for the mobile device becomes larger than a predetermined value. apparatus.

15. The timing control device according to claim 12, wherein the largest phase difference between the values of the phase differences for a plurality of branches is stored and managed as the inter-branch phase difference.

16. The timing control device according to claim 12, wherein an average value of the phase difference values for a plurality of branches is stored and managed as the inter-branch phase difference.

17. The timing control device according to claim 12, wherein the phase difference between branches is set to 0 when a phase difference is obtained only for a single branch from the same mobile station.

18.For measuring the phase difference between branches, use only the timestamp messages received within a predetermined time from the first received timestamp messages. 13. The timing control device according to claim 12, wherein:

19. The timing control device according to claim 18, wherein the predetermined time is set for each mobile device.

20. The timing control device according to claim 18, wherein the predetermined time is set to one of the wireless network control devices.

21. A timing control method for a wireless network control device in a wireless network in which a base station accommodating a mobile device and a wireless network control device for controlling a wireless network are connected by an IP protocol.

A measurement step of measuring a transmission time of each round trip of a line connecting the base stations by exchanging a time stamp message storing the time stamp with a plurality of base stations;

A storage management step of storing and managing the measured transmission time in association with the base station;

A control step of controlling transmission timing of a signal to each base station using the transmission time managed and stored;

A timing control method comprising:

22. The timing control method according to claim 21, wherein the wireless network complies with specifications defined by 3GPP.

23. The timing control method according to claim 22, wherein each of the steps is realized in a transport network layer.

24. The timing control method according to claim 21, wherein the time stamp message is a time stamp request / response message of an Internet control message protocol.

25. In the storage management step, the previously measured transmission time, the currently measured transmission time, the upper threshold and the lower threshold are stored, and the difference between the previously measured transmission time and the currently measured transmission time is stored. 22. The timing control method according to claim 21, wherein timing control is performed when the value falls outside the upper / lower threshold range.

26. The timing control method according to claim 25, wherein timing control is performed when the difference between the transmission times falls outside the upper and lower threshold ranges by a predetermined number of times or more.

27. The timing control method according to claim 26, wherein the predetermined number of times can set different values for an upper threshold and a lower threshold.

28. The timing control method according to claim 21, wherein the time stamp message is periodically transmitted at predetermined time intervals.

29. The timing control method according to claim 21, wherein the time stamp message is transmitted when a message requesting message transmission from the base station is received.

3 0. The time stamp message handles the time stamp message. 22. The timing control method according to claim 21, wherein transmission is performed only to a base station that can perform the control.

31. The method according to claim 30, wherein a time stamp message is transmitted to each base station, and whether or not the base station can handle the time stamp message is determined based on a response content returned. Timing control method.

32. Using the time stamp message, measure and manage the phase difference between a plurality of branches at the time of handover of the mobile station for each mobile station, and based on the result, determine the timing of signal transmission from the radio network controller. 22. The timing control method according to claim 21, further comprising a handover step for performing control.

33. The timing according to claim 32, wherein in the storage management step, at least a mobile device identifier, a branch identifier, an inter-branch phase difference, and a threshold value for comparison with the inter-branch phase difference are stored. Control method.

34. The timing control according to claim 32, wherein the time stamp message is transmitted when a phase difference between a plurality of branches set for the mobile station becomes larger than a predetermined value. Method.

35. The timing control method according to claim 32, wherein the largest phase difference among the values of the phase differences for a plurality of branches is stored and managed as the inter-branch phase difference.

36. The timing control method according to claim 32, wherein an average value of the phase difference values for a plurality of branches is stored and managed as the inter-branch phase difference.

37. The timing control method according to claim 32, wherein when a phase difference is obtained only for a single branch from the same mobile station, the phase difference between branches is set to 0. .

38. The measurement of the phase difference between branches uses only the timestamp message received within a predetermined time from the first timestamp message among the timestamp messages, according to claim 32. Timing control method.

39. The timing control method according to claim 38, wherein the predetermined time is set for each mobile device.

40. The timing control method according to claim 38, wherein the predetermined time is set to one of the radio network controllers.