KR100301704B1 - Packet Handoff Control without Packet Loss in Wireless Data Mobile Communication Networks - Google Patents

Abstract

According to the present invention, packet handoff of an IP level is performed through a plurality of IP addresses in order to eliminate packet loss occurring when a mobile station having an IP address performs handoff and to prevent retransmission of packets in a wireless data communication network. Its purpose is to provide a method of treatment.

According to the present invention, in a mobile station side handoff of a wireless data mobile communication network including a mobile station, a base station, a control station and a packet data service node, when the mobile station enters a handoff area, a new IP address request message is sent to a new packet. Transmitting to a data service node to be assigned a new IP address; In the first step, if a new IP address is allocated, a message indicating that a new IP address has been allocated is transmitted to a previous packet data service node, and duplicate packet data is received from the old packet data service node and the new packet data service node. A second step; In the second step, during the duplicate reception of the packet data, if the signal strength from the control station directly connected to the previous packet data service node is smaller than a predetermined value, a third step of disconnecting communication with the previous packet data service node. Provided is a mobile station side handoff method of a wireless data mobile communication network, comprising the steps of:

Description

Method of packet handoff without packet loss in wireless data telecommunication

The present invention relates to a packet handoff control method. In particular, the present invention provides a network structure for providing a packet data service in a packet-switched manner in a wireless data communication network such as IMT-2000. When moving to a packet data service node, the present invention relates to a packet handoff control method using a plurality of IP addresses without loss of packets.

There are two methods of providing packet data services in a wireless data communication network such as Future Public Land Mobile Telecommunication Systems (FPLMTS / IMT-2000). There is this.

In the existing mobile communication network, a packet data service is formed in a circuit switched method of exchanging data through an assigned channel while exclusively occupying a transmission path after establishing a call in the same manner as a voice call. This method has the disadvantage of wasting wireless resources due to the inefficient use of wireless resources and exclusively occupying the transmission path, and the burden of paying the channel fee for subscribers not having to send and receive data. There is this.

On the other hand, when providing a packet data service in a packet-switched scheme, it can meet the characteristics of data that does not require relatively real time, and can simultaneously use a radio resource because several subscribers can share a channel.

On the other hand, in the circuit-switched packet data service, when the mobile station moves, handoff is supported in the mobile network itself.However, in the packet-switched scheme, handoff is considered in the layer where the actual packet routing occurs, that is, the IP layer. need.

At the IP layer, the destination IP address is used for routing. When a mobile station moves to a new wireless subnet, the area governed by another packet data service node, a single IP address completes the move to the new packet data service node. The packet until registering the fact that the packet has been moved is lost, and for this purpose, a transmission process due to a retransmission request is required.

This method consumes more radio resources, increases overall transmission time, and, for services such as Internet Fax, disconnects the Transmission Control Protocol (TCP) connection itself due to the timer value being designed based on the fixed network. Problem occurs. In addition, frequent retransmission requests every time the mobile station handoffs cause the size of the TCP window transmitted from the host of the fixed Internet network or the protocol of another mobile station to be backed off, thereby reducing the overall network efficiency. Occurs.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art as described above, and proposes a network structure for providing a packet data service in a packet-switched manner in a wireless data communication network such as IMT-2000. It is an object of the present invention to provide a method of performing packet handoff in an efficient manner without loss of packets by using a plurality of IP addresses when moving to another packet data service node while using a data service.

1 is a system diagram of a wireless data communication network including packet data communication according to an embodiment of the present invention;

FIG. 2 is a system diagram when a plurality of IP addresses are used in the wireless data communication network shown in FIG. 1.

3 is a signal flowchart of a packet handoff control method according to an embodiment of the present invention;

4 is a flowchart illustrating a packet handoff control method shown in FIG. 3.

♠ Explanation of symbols on the main parts of the drawing ♠

100: mobile station (mobile terminal + portable computer)

101: base station 102: control station

103: packet data service node 104: location register / authenticator

105: mobile switching center 106: packet data service network

107: packet data gateway node 108: Internet host

According to the present invention for achieving the above object, in the mobile station side handoff of a wireless data mobile communication network including a mobile station, a base station, a control station and a packet data service node, when the mobile station enters the handoff region Sending a new IP address request message to a new packet data service node to receive a new IP address; In the first step, if a new IP address is allocated, a message indicating that a new IP address has been allocated is transmitted to a previous packet data service node, and duplicate packet data is received from the old packet data service node and the new packet data service node. A second step; In the second step, during the duplicate reception of the packet data, if the signal strength from the control station directly connected to the previous packet data service node is smaller than a predetermined value, a third step of disconnecting communication with the previous packet data service node. Provided is a mobile station side handoff method of a wireless data mobile communication network, comprising the steps of:

Further, in a previous packet data service node side handoff of a wireless data mobile communication network including a mobile station, a base station, a control station, and a packet data service node, upon receiving a message indicating that a new IP address has been allocated from the mobile station, the packet data is received. There is provided a method for handing off a previous packet data service node side of a wireless data mobile communication network comprising the step of transmitting a duplicate transmission to a mobile station and a new packet data service node.

Further, in a new packet data service node side handoff of a wireless data mobile communication network including a mobile station, a base station, a control station, and a packet data service node, upon receiving a new IP address request message from the mobile station, a new IP address assignment message is received. A first step of transmitting to the mobile station; A new packet data service node side handoff method is provided in a wireless data mobile communication network, comprising receiving a packet data from a previous packet data service node, the second step of sending packet data to the mobile station.

Further, in a handoff of a wireless data mobile communication network including a mobile station, a base station, a control station, and a packet data service node, when the mobile station enters a handoff area, a new IP address request message is sent to a new packet data service node. A first step of allocating a new IP address; In the first step, if the mobile station is assigned a new IP address, after transmitting a message to the previous packet data service node that the new IP address has been allocated, the old packet data service node sends packet data to the mobile station and the new packet. A second step of transmitting the data service node in duplicate; In the second step, the new packet data service node receiving the packet data transmits the received packet data to the mobile station; In the second and third steps, if the signal strength from the control station directly connected to the previous packet data service node is smaller than a predetermined value while the mobile station is repeatedly receiving packet data, the previous packet data service node And a fourth step of cutting off communication with the wireless data mobile communication network.

Further, in a computer-readable recording medium for performing a mobile station side handoff method of a wireless data mobile communication network including a mobile station, a base station, a control station and a packet data service node, when the mobile station enters a handoff area, Transmitting a new IP address request message to a new packet data service node to receive a new IP address; In the first step, if a new IP address is allocated, a message indicating that a new IP address has been allocated is transmitted to a previous packet data service node, and duplicate packet data is received from the old packet data service node and the new packet data service node. A second step; In the second step, a third step of receiving and receiving only the duplicated packet data through a transmission control protocol (TCP); In the second and third steps, during the duplicate reception of the packet data, if the signal strength from the control station directly connected to the previous packet data service node is smaller than a predetermined value, communication with the previous packet data service node is performed. A computer readable recording medium having recorded thereon a program for executing the fourth step of cutting is provided.

A computer-readable recording medium for performing a previous packet data service node side handoff method of a wireless data mobile communication network including a mobile station, a base station, a control station, and a packet data service node, the method comprising: receiving a new IP address from the mobile station; Receiving a message indicating that the message has been allocated, transmitting packet data redundantly to the mobile station and a new packet data service node; In the first step, executing a second step of disconnecting communication with the mobile station when a communication disconnection request message is received from the mobile station while repeatedly transmitting packet data to the mobile station and the new packet data service node. A computer readable recording medium having recorded thereon a program is provided.

A computer-readable recording medium performing a new packet data service node-side handoff method of a wireless data mobile communication network including a mobile station, a base station, a control station, and a packet data service node, comprising: requesting a new IP address from the mobile station Receiving a message, sending a new IP address assignment message to the mobile station; Upon receiving packet data from a previous packet data service node, a computer-readable recording medium having recorded thereon a program for executing the second step of transmitting packet data to the mobile station is provided.

In the following, with reference to the accompanying drawings, a preferred embodiment according to the present invention will be described in detail.

1 is a system diagram of a wireless data communication network including packet data communication according to an embodiment of the present invention.

1, the system configuration of a wireless data communication network including packet data communication according to an embodiment of the present invention is a mobile station (100, MS: Mobile Station), base station (101, BTS: Base Transceiver System), the control station ( 102, BSC (Base Station Controller), Packet Data Service Node (103, PDSN: Packet Data Service Node), Location Register (104, LR: Location Register), Mobile Switching Station (105, MSC: Mobile Switching Center), Mobile Packet Data The service backbone network 106 includes a mobile packet data service backbone network (mPDS BN), a packet data gateway node (107), and an internet host (108).

The operation principle of the wireless data communication network including the packet data communication shown in FIG. 1 will be described in detail as follows.

Mobile station 100 is a mobile subscriber station, which requires additional computing functionality (eg, a notebook computer) to use packet data services. The mobile station has a wireless connection with the base station and is characterized by mobility.

The base station 101 performs a wired / wireless connection function between the mobile station and the control station, CDMA signal processing, and a wireless connection function with the mobile station.

The control station 102 performs mobile call control, handoff control for voice calls, channel allocation for CDMA voice data processing, and power control functions.

When there is a packet service request from the mobile station, the packet data service node 103 performs packet service by a procedure defined with each other. That is, an IP address is assigned to the mobile station to provide a packet data service, and packet handoff is performed according to a change in the location of the mobile station.

The location register 104 performs a function of finding and storing location information of the mobile station whenever the location of the mobile station changes or periodically. In addition, when there is an incoming call to a mobile station, it finds in which area the mobile station is located and provides location information.

The mobile switching center 105 performs circuit switching, handoff, paging, roaming, and subscriber authentication based on circuit switching between mobile subscribers and incoming and outgoing call processing.

The mobile packet data service backbone network 106 is a network for interworking these devices when there are several packet data service nodes interconnected with the base station located closest to the mobile station. The packet data service nodes use IP in IP or tunneling to exchange necessary information with each other. The packet data service nodes are also connected to the packet data gateway node 107 for internet service. The mobile packet data service backbone network is a network connecting packet data service nodes and packet data service gateway nodes.

The packet data gateway node 107 determines which packet data service node to send packet information to according to address translation between the mobile network and the Internet and the location of the subscriber, and transmits it through a tunneling technique. It also performs packet data transmission and reception from the mobile network to the Internet.

The internet host 108 is a computer fixed to the existing Internet network to provide Internet services.

FIG. 2 is a system diagram when a plurality of IP addresses are used in the packet data service network shown in FIG. 1.

The code division multiple access (CDMA) mobile communication network simultaneously receives voice signals from the call channels of two base stations within the handoff procedure, and resets the call channel to a place where the signal strength is strong among the received voice signals. Therefore, a little more resources are required, but ultimately, it is an advantage of providing a good quality communication service to subscribers without interruption during a call.

In general, when the same frequency is used in a CDMA mobile network, a handoff between base stations managed by the same control station is caused by soft handoff. In recent years, research has been conducted to provide soft handoff between control stations by connecting the control stations to each other and providing only the same frequency between the control stations.

This embodiment is based on the soft handoff between the control stations in the communication network configuration as shown in FIG. 2, when the mobile station enters another control station beyond the area of the control station in service and generates a soft handoff, the packet of the network layer is generated. By allowing duplicate reception through two paths at the same time, no packet loss occurs.

The packet data service node, the control station, and the base station are basic units configuring a subnet (SubNet). As shown in FIG. 2, two packet forwarding paths 200 and 201 exist during handoff.

In the circuit-switched data service support network, a new route is established from the channel occupied by the voice to the new channel. However, in a packet-switched network, when a mobile station moves to another base station, the mobile station must notify itself of the newly entered base station and inform the location register 104 of its own move. When all of these steps are completed, the packet can be transmitted from the newly established base station. That is, some of the packets that were in transit are lost, and the remaining packets are retransmitted from the other host by the retransmission request only after the handoff of the mobile station is completed. In addition, even if the mobile station moves to a new control station while using the service, using multiple IP addresses, as in the case of circuit-switched voice transmission, does not cause any loss of information and does not require retransmission. Quality can be provided to the subscriber.

3 is a signal flowchart of a packet handoff control method according to an embodiment of the present invention, and FIG. 4 is a flowchart illustrating a packet handoff control method shown in FIG. 3.

In step 400, the handoff control procedure to which the present invention is applied is initiated when the mobile station moves from the old packet data service node OldPDSN where it was originally located to the new packet data service node NewPDSN, where the mobile station moves to its new area. The fact that entry is made is known according to the protocol determined by the radio procedure of the mobile network. At this time, the mobile station transmits a new IP address (COA: Care-Of-Address) request message to the new packet data service node in preparation for packet transmission (NewCOA_Req: 300).

Then, in step 401, the new packet data service node receives the COA request message of the mobile station and assigns a new IP address COA (NewCOA_Assign: 301).

The mobile station is then assigned a new IP address to have two IP addresses, and at step 402, it informs the previous packet data service node that the new address has been allocated and ready to receive packets (NewCOA_Notify: 302).

In addition, the new packet data service node transmits a message requesting registration of the mobile station to the home packet data service node HomePDSN for location registration in step 403, since the mobile station has entered its area (step S403). Registration_Req: 303).

Then, in step 404, the previous packet data service node transmits the packet to the mobile station as in the existing packet transmission process (Packet_Send: 304), and simultaneously, in step 405, copies the packet to the new packet data service node of the mobile station. Relay transmission (Packet_Forward: 305). At this time, the destination address of the packet sent by the previous packet data service node is the address of the new packet data service node. In addition, the new packet data service node sends a packet transmitted to the mobile station to the corresponding mobile station (Packet_Send: 306).

Then, in step 406, it is determined whether all the packets in the buffer have been transmitted.

As a result of the determination in step 406, if all packets in the buffer have not been transmitted, steps 404, 405, and 406 are repeated. On the other hand, the mobile station receives duplicate packets from a plurality of packet data service nodes through the above process, and the duplicated packets are selectively accommodated by a transmission control protocol (TCP). If a packet is not selected, it is discarded.

As a result of the determination in step 406, when all the packets in the buffer are transmitted, the signal strength from the previous packet data service node is lowered to a predetermined value or less. In step 407, the mobile station requests binding update from the previous packet data service node. Send the message (BindingUpdate_Req: 308).

Then, in step 408, the previous packet data service node completes the binding update and sends the result back to the mobile station (BindingUpdate_Ack: 309).

This ends communication with the previous packet data service node, and in step 409 the mobile station transmits a packet to the new packet data service node with each other (Packet_Send: 310). At this time, the COA used in the previous packet data service node is no longer used.

Meanwhile, the present invention can be utilized not only in the case of providing a packet data service in a mobile network, but also in a mobile IP that is currently being promoted.

As described in detail above, the present invention provides a method for processing an IP level packet handoff through a plurality of IP addresses, thereby eliminating packet loss occurring when a mobile station having an IP address performs a handoff, and a wireless data communication network. Since the packet is not retransmitted within the service, the service usage time of the subscriber is reduced, and the radio resource is efficiently used in comparison with the wired network.

The technical spirit of the present invention has been described above with reference to the accompanying drawings. However, the present invention has been described by way of example only, and is not intended to limit the present invention. In addition, it is obvious that any person skilled in the art can make various modifications and imitations without departing from the scope of the technical idea of the present invention.

Claims (3)

A handoff control method for supporting roaming between wireless data networks in a wireless data mobile communication network including a mobile station, a base station, a control station, and a packet data service node, An eleventh step of, when the mobile station enters a handoff area, sends a new IP address request message to a new packet data service node to be assigned a new IP address; Performing a procedure of transmitting a message indicating that a new IP address has been allocated to a previous packet data service node, and receiving packet data from the old packet data service node and the new packet data service node in duplicate. Steps; Performing a thirteenth step of disconnecting the communication with the previous packet data service node if the signal strength from the control station connected to the previous packet data service node is smaller than a predetermined value during the duplicate reception of the packet data; When the old packet data service node receives a new IP address assignment message from the mobile station, the packet data service node transmits the packet data to the mobile station and the new packet data service node in duplicate. The new packet data service node, when receiving a new IP address request message from the mobile station, transmitting a new IP address assignment message to the mobile station; And twenty-second step of transmitting the received packet data to the mobile station when the packet data is received from the previous packet data service node. The method of claim 1, In the twelfth step, the method further comprises a fourteenth step of selecting and receiving only one packet data duplicated from the old packet data service node and the new packet data service node through a transmission control protocol (TCP). Handoff method of wireless data mobile communication network. The method of claim 1, The previous packet data service node disconnects communication with the mobile station when a communication disconnection request message is received from the mobile station while repeatedly transmitting packet data to the mobile station and the new packet data service node. Handoff control method of wireless data mobile communication network.