Patent Publication Number: US-2003227941-A1

Title: Apparatus and method for converting signal in mobile communication system

Description:
BACKGROUND OF THE INVENTION  
       [0001] 1. Field of the Invention  
       [0002] The present invention relates to a mobile communication system, and particularly, to an apparatus and a method for converting signals between mobile communication systems of different generations.  
       [0003] 2. Background of the Related Art  
       [0004] Mobile communication system can be classified into a first generation mobile communication system transmitting voice signal using an analog frequency modulation (for example, advanced mobile phone service (AMPS)), a second generation mobile communication system such as IS-95 standard mainly transmitting digital voice signal, and a third generation mobile communication system such as IMT-2000 standard that is able to transmit high speed and ultra-high speed data as well as the voice signal as being developed.  
       [0005] Generation shifts in technology and science fields are made gradually, and therefore, a shift into the new system is also made gradually. As a result of the shift, communication between the old and the new systems is inevitable.  
       [0006] An InterProcessor Communication (IPC) is a function supported by the systems so that two processors can communicate with each other, that a processor on one side (processor A) communicates with another processor in the same system (processor B) or with a processor of other system (processor C)/or controls it. Therefore, the processor A transmits a ping signal to the processor C, and grasps IPC path by analyzing returned ping reply signal. The processes of transmitting the ping signal and analyzing the ping reply signal are referred to as ‘IPC test’.  
       [0007] For the IPC test, generally third generation system (hereinafter, referred to as ‘3G system’) uses an ICMP echo request message (hereinafter, referred to as ‘ping’), the second generation system hereinafter, referred to as ‘2G system’) uses an echo request message (hereinafter, referred to as ‘ipclog’), and the IPC tests of the two systems are defined in a standard. However, since the communication between the 2G system and the 3G system is not defined in the standard, the IPC test from the 3G system to the 2G system or from the 2G system to the 3G system can not be performed according to the conventional art.  
       SUMMARY OF THE INVENTION  
       [0008] An embodiment of the present provides an apparatus and method for communication between different systems. According to one embodiment, there is provided an apparatus for converting signals in a mobile communication system comprising: a 3G system; a 2G system performing an IPC test with the 3G system; and a signal converting means for converting an IPC test signal of the 3G system into an IPC test signal of the 2G system or converting inversely.  
       [0009] Desirably, the signal converting means is installed on a gateway located between the 3G system and the 2G system. Desirably, the signal converting means comprises a protocol stack including a layer for converting an ICMP and IPoA of the 3G system into IPCLOG of the 2G system or converting inversely; a layer for converting AAL5 of the 3G system into an IPC of the 2G system or converting inversely; and a layer converting an ATM cell of the 3G system into an IPC packet of the 2G system or converting inversely.  
       [0010] In another embodiment, there is provided a method for converting signals in a mobile communication system. The method comprising: a step of receiving an IPC test signal (ping signal) of a 3G system; a step of converting the received ping signal into an IPC test signal (ipclog signal) of a 2G system; a step of transmitting the ipclog signal to a destination processor in the 2G system network; a step of receiving ipclog reply signal from the destination processor; a step of converting the received ipclog reply signal into an IPC test response signal (ping reply signal) of the 3G system; and a step of transmitting the generated ping reply signal to the source of the ping signal.  
       [0011] In another embodiment, there is provided a method for converting signals in a mobile communication system comprising: a step of receiving an IPC test signal (ipclog signal) of a 2G system; a step of converting the receive ipclog signal into an IPC test signal (ping signal) of a 3G system; a step of transmitting the ping signal to a destination processor in the 3G system network; a step of receiving a ping reply signal from the destination processor; a step of converting the received reply signal into an IPC test response signal (ipclog reply signal) of the 2G system; and a step of transmitting the generated ipclog reply signal to the ipclog signal source. Desirably, the step of converting the ipclog signal into the ping signal comprises: a step of converting the IPCLOG of the 2G system into an ICMP and an IPoA of the 3G system; a step of converting an IPC of the 2G system into an AAL5 of the 3G system; and a step of converting an IPC packet of the 2G system into an ATM cell of the 3G system. Desirably, the step of converting the ping reply signal into an ipclog reply signal comprises: a step of converting the ICMP and the IPoA of the 3G system into the IPCLOG of the 2G system; a step of converting the AAL5 of the 3G system into the IPC of the 2G system; and a step of converting the ATM cell of the 3G system into the IPC packet of the 2G system.  
       [0012] Additional advantages, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The advantages of the invention may be realized and attained as particularly pointed out in the appended claims. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0013] The invention will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:  
     [0014]FIG. 1 is a block diagram showing a mobile communication system according to an embodiment of the present invention;  
     [0015]FIG. 2 is a flow chart of a signal for performing an IPC test according to an embodiment of the present invention;  
     [0016]FIG. 3 is a view showing a 2G system, a protocol converter and a protocol stack of a 3G system according to an embodiment of the present invention; and  
     [0017]FIG. 4 is a view showing a data unit configuration of respective layers shown in FIG. 3.  
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
     [0018] The present invention provides a method for communicating between two systems so that a 3G system (or 2G system) performs an IPC test toward a 2G system (or 3G system). As shown in the FIG. 1 embodiment, the mobile communication system comprises: a 3G system  10 ; a 2G system  30  performing an IPC test with the 3G system  10 ; and a protocol converter  20  for converting an IPC test signal of the 3G system into an IPC test signal of the 2G system or for converting inversely.  
     [0019] The protocol conversion means that information except source data (for example, header, etc.) among the components of a signal going toward a destination system (for example, IPC packet, ATM cell, etc.) is converted into the form suitable for the destination system. The protocol converter  20  performs the protocol conversion for communicating between the two systems  10  and  30 , and comprises a predetermined memory required for the protocol conversion and a CPU controlling the memory.  
     [0020]FIG. 2 is a flow chart of a signal for performing the IPC test, and shows the IPC test performed from the 3G system to the 2G system. In order to perform the IPC test, the 3G system  10  generates an IPC test signal (hereinafter, referred to as ‘ping signal’), and transmits the generated ping signal to the protocol converter  20  (S 10 ). The protocol converter  20  converts the protocol of the received ping signal to generate an IPC test signal of the 2G system (hereinafter, referred to as ‘ipclog signal’) (S 20 ), and transmits the generated ipclog signal to a destination processor in the 2G system network (S 30 ).  
     [0021] On receiving the ipclog signal, the 2G system  30  generates a response signal of the IPC test signal (hereinafter, referred to as ‘ipclog reply signal’) and transmits it to the protocol converter  20  (S 40 ), and the protocol converter  20  converts the protocol of the received ipclog reply signal to generate a response signal of the IPC test signal (hereinafter, referred to as ‘ping reply signal’) of the 3G system (S 50 ) and transmits the generated ping reply signal to the ping signal source (S 60 ). Since the 3G system has an ATM based network configuration, the protocol of the ping signal should be converted (ATM cell→IPC packet) and address mapping is performed in order to transmit the ping signal to the 2G system network  20 . The above operations are performed by the protocol converter  20  installed on a gateway  21 .  
     [0022] When passing through the gateway  21 , the ping signal is converted into the ipclog signal and the transmission type of the ping signal is converted from the ATM cell into the IPC packet, and then, the signal is transmitted into the 2G system  30 . In addition, the ipclog signal transmitted to the 2G system  30  is transmitted to the destination processor according to the IPC test procedures of the 2G system  30 .  
     [0023] The destination processor receiving the ipclog signal generates a predetermined response signal (ipclog reply signal) and sends the signal to the ping signal source (S 30 ). The ipclog reply signal sent from the 2G system  30  is transmitted to the 3G system  10  after passing through the gateway  21 . The gateway  21  converts the ipclog reply signal to the ping reply signal, and also converts the signal transmission type (IPC packet) to the ATM cell.  
     [0024] In addition, when the ping reply signal is received, the 3G system  10  delivers the signal to the ping signal source according to the IPC test procedures of the 3G system  10  (S 40 ). In above process S 20 , when the ping signal of the 3G system is converted into the ipclog signal, the ipclog signal processing in the 2G system is performed according to the IPC test procedures of the 2G system. The IPC test performed from the 2G system  30  to the 3G system  10  to the reverse direction of the signal flow shown in FIG. 2.  
     [0025]FIG. 3 is a view showing the 2G system, the protocol converter and a protocol stack of the 3G system. As shown therein, the protocol stack of the 3G system  10  comprises a layer for performing internet control message protocol (ICMP), a layer for performing IP over ATM (IPoA), a layer for performing ATM adaptation layer  5  (AAL5), and a layer for generating asynchronous transfer mode (ATM) cell. And the protocol stack of the 2G system  30  comprises a layer for performing inter processor communication LOG (IPCLOG), a layer for performing inter processor communication (IPC), and a layer for generating the IPC packet.  
     [0026] The IPoA is a definition about procedures for communicating between IP hosts in one logical IP subnet (LIS) directly using the ATM network and an address converting method, and an essential content of the IPoA is an address conversion for converting the IP address into the ATM address. The ICMP is a protocol for controlling a message and error notification between a host server and an internet gateway and defined on RFC  792 . When the ping signal performs the IPC test or the internet connection test, the ICMP is used.  
     [0027] When the IPC test signal (ping signal) of the 3G system is converted into the IPC test signal (ipclog signal) of the 2G system, the ICMP and IPoA of the ping signal are converted into the IPCLOG, the AAL5 of the ping signal is converted into the IPC, and the ATM cell of the ping signal is converted into the IPC packet. In contrast, when the IPC test response signal (ipclog reply signal) of the 2G system is converted into the IPC test response signal (ping reply signal) of the 3G system, the IPCLOG of the ipclog reply signal is converted into the ICMP and IPoA, the IPC of the ipclog reply signal is converted into the AAL5, and the IPC packet of the ipclog reply signal is converted into the ATM cell.  
     [0028]FIG. 4 is a view showing data unit configurations of the respective layers shown in FIG. 3. As described above, the mobile communication system according to an embodiment of the present invention is realized so that the second generation system is able to perform the IPC test for the third generation system or the third generation system is able to perform the IPC test for the second generation system by communicating between the second generation system and the third generation system.  
     [0029] The foregoing embodiments and advantages are merely exemplary and are not to be construed as limiting the present invention. The present teaching can be readily applied to other types of apparatuses. The description of the present invention is intended to be illustrative, and not to limit the scope of the claims. Many alternatives, modifications, and variations will be apparent to those skilled in the art. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents but also equivalent structures.