KR100944634B1 - Apparatus for hot swapping in software defined radio and mehtod for operating the same - Google Patents

Abstract

The present invention relates to a hot swapping device for software-based wireless communication and a method of operating the same, which can eliminate latency and packet loss when there is a network connection change. According to the present invention, when a hot swapping middleware performing a change connection in a network changes connection from a first network to a second network in an SCA-compliant software-based wireless communication (SDR), a new second in addition to the existing first modem is used. A first step of driving a modem to obtain an IP address of the second modem, and simultaneously transmitting and receiving packets from the first network and the second network through the first modem and the second modem to perform multi-wireless communication And a third step of stopping the driving of the first modem and completing a handoff by transmitting and receiving a packet only through the second modem.

SCA, SDR, Network, Handoff, IP, Middleware, Latency, Packet Loss

Description

Apparatus for hot swapping in software defined radio and mehtod for operating the same}

The present invention relates to a hot swapping device for software-based wireless communication and a method of operating the same.

SCA (Software Communication Architecture) is a standardized communication software structure proposed to greatly improve interoperability between different communication systems and to reduce development and deployment costs. The SCA is composed of a hierarchical structure of an application and an operating environment, and the dual operating environment includes a real-time operating system (RTOS), a core framework (CF), and a KOVA. It consists of the Common Object Request Broker Architecture (CORBA) interface. SCA adopts CORBA (Common Object Request Broker Architecture), an industry standard for distributed object models, as a middleware to provide an integrated environment of different types of hardware and software. It is an independent system design framework.

Therefore, the SCA based application system refers to a communication system based on the SCA structure. As a representative example of the SCA based application system, a plurality of wireless communication standards can be obtained through the conversion of modular software without modification of hardware. There are multiple acceptable Software Defined Radio (SDR) systems, which adopt SCA as a standard for the software framework.

As described above, software-based wireless communication (SDR) has recently received rapid attention for interworking in different wireless networking technology fields. This SCA-compliant software-based radio (SDR) provides switching and self-configuration in radio protocols on different networks.

However, in the conventional software-based radio communication (SDR) that drives a standard upper layer protocol stack such as TCP / IP, radio protocol switching (change) is not performed without affecting application performance.

Usually, each radio protocol switching (change) has a change in the IP address of the SDR device if there is no base station and radio access point belonging to the same network. Switching (modification) in IP addresses results in discontinuities in traditional connection-oriented protocols such as TCP. This problem of discontinuity may be solved by mobile IP and Universal Seamless Handoff Architecture (USHA), which require a lot of handoff latency and the cost of the underlying design.

However, their adoption has the problem of causing data loss due to handoff latency. In addition, the cost of building a baseline design is expensive and difficult to implement in the field. On the other hand, a lot of handoff latency when executed by an application has the problem of causing data loss which ultimately leads to a deterioration in terms of quality of service (QoS).

The present invention proposes hot swapping to eliminate latency and packet loss when there is a handoff to different types of networks.

The present invention provides an antenna module comprising two or more individual antennas and an antenna module for transmitting and receiving different waveforms from a plurality of wireless networks, respectively, and a modem module having a plurality of modems respectively matched to the individual antennas to perform modulation and demodulation; The modem control module controls the operation of each modem in the modem module, and when the connection change occurs in the SCA standard software-based wireless communication (SDR) to a different network, the modem control module is used to prevent disconnection. A new second modem is driven in addition to one modem to simultaneously transmit and receive packets through the different networks, and after a predetermined time, the first modem is stopped and a packet is transmitted and received through only the second modem. It includes hot swapping middleware.

In addition, the present invention is a hot swapping middleware that performs a change connection in the network, when the connection change occurs from the first network to the second network in the SCA standard software-based wireless communication (SDR), new communication in addition to the existing first modem A first step of driving a second modem to obtain an IP address of the second modem, and simultaneously transmitting and receiving packets from the first network and the second network through the first modem and the second modem to perform multi-wireless communication; And a third step of completing the handoff by stopping the driving of the first modem and transmitting and receiving a packet only through the second modem.

In the first step, the modem control module performing modem control forms a connection configuration with the second antenna through the initialization of the second modem according to the instruction of the hot swapping middleware, and the modem control module performs the second control. Obtaining an IP address of a modem, and transmitting, by the modem control module, the obtained IP address to the hot swapping middleware.

The second step may include performing a handshaking indicating a start of signal exchange between the second modem and the second network, and transmitting an IP packet (original IP packet) from an IP layer in which the hot swapping middleware is an upper layer. And replaces the IP address of the first modem in the source IP field with the IP address of the second modem in the original IP packet and the IP address of the first network in the destination address field with the IP address of the second network. Generating a duplicate IP packet, transmitting the original IP packet and the duplicate IP packet to a modem control module performing modem control, wherein the modem control module delivers the original IP packet to the first modem, Transmitting the duplicated IP packet to a second modem to perform multi-radio communication.

The performing of the handshaking may include: transmitting, by the hot swapping middleware, a multi-communication request IP packet indicating a multi-radio communication request to the second network according to an SCA standard, and receiving the multi-communication request IP packet. And the second network transmits an ACK to the hot swapping middleware to complete handshaking.

The multi-communication request IP packet is a packet including information of <hot swap, parallel, ip1, and ip2>, wherein the 'hot swap' is a message indicating that it is currently in a mode for hot swapping, and 'parallel' is simultaneously The message indicates that the multi-communication will be performed, and ip1 indicates an IP address of the first modem and ip2 indicates an IP address of the second modem.

In the third step, if it is determined that the connection between the first modem and the first network is to be terminated, the hot swapping middleware transmits a connection termination IP packet requesting termination of the connection to the first network; The second network receiving the connection termination IP packet transmits an ACK to the hot swapping middleware to complete the termination of the connection.

The connection termination IP packet is a packet including information of <hot swap, swap, ip1, ip2>, wherein the 'hot swap' is a message indicating that it is currently in a hot swapping mode, and the 'swap' is a hot swapping. This indicates that the connection is terminated, wherein ip1 is an IP address of the first modem and ip2 is an IP address of the second modem.

As a result, hot swapping using the software of the present invention provides an automatic mechanism for upgrading or reconfiguring software, components, and the operation of the entire software is performed in a non-interrupted manner. Therefore, having a stop time near '0' or '0' eliminates waiting time during handoff. In addition, the hot swapping mechanism of the present invention does not cause packet loss without a separate base design.

The present invention is suitable for wireless communication of the SCA standard. This is because SCA is provided modularly and provides an independent platform for defining wireless communication. In addition, the present invention can be applied to the wireless communication definition of other reconfiguration. Thus, the present invention can be implemented in all cases where hot swapping middleware can be executed.

Hereinafter, a detailed description of embodiments of the present invention will be described with reference to the accompanying drawings. In the following description of the reference numerals to the components of the drawings it should be noted that the same reference numerals as possible even if displayed on different drawings.

1 is a diagram illustrating how hot swapping is performed when different wireless networks overlap each other according to an exemplary embodiment of the present invention.

The present invention provides middleware based on a hot swapping mechanism in protocol stack switching. In the above, hot swapping means that the mobile terminal switches (changes) a connection interface between networks on a different wireless network without terminating the interface between the networks.

Protocol stack switching that occurs when a network is changed in connection is called network hot swapping.

As shown in FIG. 1, it is assumed that a plurality of radio network cells overlap in the same place, and a user's mobile terminal communicates on a network using SCA standard wireless communication. In addition, it is assumed that a mobile terminal performs file transmission on the Internet together with SCA standard wireless communication.

At this time, when there is a movement of a user having a mobile terminal, that is, when moving from one network to another network, handoff (roaming) will be performed on a plurality of networks.

This handoff can be made in a number of cases, in which cells of the same network type, for example, handoff from WLAN1 10 to WLAN2 11 (so-called 'horizontal handoff') can be made. In the case of the horizontal handoff, handoff can be easily achieved by the protocol itself.

However, when the user moves to another type of network, for example from WLAN2 11 to GPRS 12, or from GPRS 12 to WLAN2 11, handoff alone cannot be achieved by the protocol itself. Because, when moving to another network, the IP is changed, the TCP session is interrupted by the IP change, and the source needs information about the new IP allocation of the SDR, which causes the packet to be changed due to the network connection change. Loss occurs.

In order to overcome this problem, the present invention provides a hot swapping mechanism for smooth handoff when there is a move to another network type as described above, thereby achieving '0' latency and '0' packet loss.

To this end, a mobile terminal having a handoff is provided with an antenna module including a dual antenna having two antennas or two antennas receiving two waveforms transmitted from different types of networks. This is because a single antenna cannot simultaneously receive two waveforms. When the handoff is performed between different types of networks, the present invention can achieve '0' latency and '0' packet loss through the antenna module and the hot swapping mechanism.

Hot swapping middleware that performs the hot swapping mechanism is provided in a mobile terminal that performs a handoff. The operation of the hot swapping middleware will be described with reference to FIG. 2.

2 is a block diagram illustrating a hot swapping apparatus for implementing hot swapping according to an exemplary embodiment of the present invention.

The hot swapping device 20 is configured to be formed on a physical layer, which is a first layer, a LLC layer, which is a second layer, and a network layer, which is a third layer. Accordingly, the hot swapping apparatus of the present invention includes both the physical layer related hardware implementation module and the data link / network related software implementation module. In order to help the understanding of the present invention, only the parts related to the IP of the network layer will be described.

When the modem control module 22 receives a signal change command from the hot swapping middleware corresponding to the MAC layer (LLC) position, the modem control module 22 newly selects the modem to change the network.

The antenna module 24 is composed of dual antennas or multi antennas of the first antenna and the second antenna which can internally receive two or more waveforms individually, thereby preventing '0' packet loss during hot swapping on the network. It is necessary to achieve. In general, packet loss in software-based mobile communications (SDR) occurs due to long delays during network switching on one antenna structure. Therefore, the present invention can continuously perform full-duplex operation without delay when the hot swapping is performed, which is a network connection change, so that packet loss does not occur when hot swapping is performed on the network.

The modem module 23 is provided with a modem as many as the number of internal antennas of the antenna module so as to process transmission and reception signals of different waveforms in the antenna module. The modem consists of a modulator and a demodulator for processing the transmit and receive waveforms at each antenna.

The hot swapping middleware 21 performs a function of determining when to perform a handoff (change) between different types of networks. In this case, the hot swapping middleware 21 controls the modem control module to instruct network change.

That is, when the mobile terminal with the hot swapping device 20 receives the data on all the networks (eg, WLAN, GPRS, CDMA) simultaneously through the multi-radio protocol, the mobile terminal may receive another radio while receiving / transmitting the data. Channel information for the protocol can be measured, where the hot swapping middleware 21 determines to change the network.

For this purpose, the hot swapping middleware 21 instructs the modem control module to operate a new modem 23b (second modem) in addition to the modem 23a (first modem) originally communicated. By operating the new second modem 23b, the connection interface with the two networks is simultaneously maintained in parallel for a while. The first antenna 24a and the second modem 23b connected to the first modem 23a are maintained. Through the second antenna 24b, which is connected to the two parallel connection interfaces, the two parallel connection interfaces are maintained continuously during the soft switching / handoff. Thereafter, the hot swapping middleware 21 instructs the modem control module 22 to stop the existing first modem 23a, thereby terminating the operation of the existing first modem 23a and the new second modem 23b. By sending and receiving packets only through), hot swapping with '0' latency and '0' packet loss in handoff can be achieved.

3 is a flowchart illustrating a process of performing hot swapping in software-based wireless communication (SDR) according to an embodiment of the present invention.

A mobile host performing SCA-compliant software-based wireless communication (SDR) communicates with any one network, for example, the first modem and the first network (S31), and then moves to another type of second network by a user's movement. For example, if there is a need to change from WLAN1 to GPRS to connect, a hot swapping mechanism is established to allow a seamless change of the network.

The hot swapping middleware issues a hot swapping instruction S32 to the modem control module to change the network. The modem control module then initializes the new modem configuration. As a second modem, which is a new modem, the second modem is initialized and configured to connect the second modem to the second antenna, and then an IP address of the second modem is obtained (S33).

Referring to FIG. 4, which is a flowchart of initial driving of a new second modem, the modem control module 22 which receives the hot swapping instruction S41 from the hot swapping middleware 21 is separated from the second antenna S430. The antenna separation initialization instruction (S42) as possible, and the modem control module 22 initializes the configuration of the second modem (S44) and initializes the configuration so that the second modem is connected to the second antenna (S45).

Thereafter, an IP address of the second modem is obtained (S46) so that the IP address passes through the modem control module to be transmitted to the upper layer hot swapping middleware (S47, S48).

On the other hand, after the second modem as a new modem is configured as described above to obtain the corresponding IP address (S33), the hot swapping middleware simultaneously performs the multi-radio communication (S35) through the first modem and the second modem.

In order to maintain communication between the existing first modem and the first network (e.g., WLAN1) and simultaneously maintain communication between the newly initialized second modem and the second network (e.g., GPRS), the newly constructed second An initial session must be established between the modem and the second network.

The process of the multi-radio communication (S34) is shown in Figure 5, wherein the initial session is first performed by handshaking (handshaking) to inform the start of the signal exchange between the middleware between the hot swapping middleware in the mobile terminal and the second network (S51) Should be After the handshaking is completed, the original IP packet is duplicated to generate a duplicate IP packet (S52), and then the original IP packet and the duplicate IP packet are transmitted to each network through each modem (S53), thereby multi-radio communication is performed. Can be done.

First, referring to the state of performing the handshaking (S51), the hot swapping middleware in the mobile terminal transmits a multi-communication request IP packet to the middleware of the second network of the other party. The multi-communication request IP packet has a format having information of <hot swap, parallel, ip1, ip2>. The multi-communication request IP packet is a packet for notifying that simultaneous communication is performed in parallel with two networks for hot swapping. The 'hot swap' is a message for notifying that a mode is currently in hot swapping, and 'parallel' Is a message indicating that the multi-communication will be performed at the same time, ip1 represents the IP address of the first modem and ip2 represents the IP address of the second modem.

The middleware of the second network receiving the multi-communication request IP packet transmits an acknowledgment (ACK) to complete handshaking, thereby performing multi-communication. The middleware of the second network is the middleware in the server of the second network existing on the same layer as the hot swapping middleware of the mobile host, and the hot swapping middleware of the mobile host and the middleware of the second network are hot at the same layer location. Exchange signals for swapping.

When the handshaking operation (S51) is completed and the communication channel is formed between the second modem and the second network, the hot swapping middleware transmits two multi-communications in parallel through the first modem and the second modem for a while and transmits them to each network. This is possible at the same time. For this transmission, a source IP replacement and a destination address replacement are duplicated to generate a duplicate IP packet (S52), and then transmitted (S53). This will be described.

Source address replacement

When the application sends data to be sent to the IP layer, the IP layer generates an IP packet and sends it to the hot swapping middleware. The hot swapping middleware duplicates the received IP packet (the original IP packet) and generates one more, wherein the replication uses the IP address of the first modem in the source address field as the IP address of the new second modem. Substitute a duplicate IP packet.

Replacement of the destination address

Upon generation of the duplicate IP packet, the IP address of the destination address field is also replaced, which duplicates the IP address of the first network in the destination address field as a second network IP address. Create an IP packet.

After the duplicated IP packet is generated (S52) as described above, the hot swapping middleware transmits the original IP packet and the duplicated IP packet to the modem control module. The modem control module gives each packet to each corresponding modem according to the IP mapped to the MAC address. Each modem generates a physical frame with each received packet and transmits it (S53), thereby performing multi-radio communication. That is, the original IP packet is delivered to the first modem, and the duplicated IP packet is delivered to the second modem for transmission.

Meanwhile, when the existing first network connection is terminated after the multi-wireless communication (S34) through the parallel connection interface is performed for a while as described above, the hot swapping middleware determines to stop the first modem (S35). The multi-radio communication S34 continues until the first modem stop determination S35 is made.

When the first modem stop determination is made, handshaking (handshaking) is performed to inform the stop of the existing first modem is driven (S36).

In detail, when the hot swapping middleware maintains the connection with the new second network and wants to terminate communication between the existing first networks, the hot swapping middleware transmits the connection termination IP packet to the middleware of the first network to terminate the connection. do.

The connection termination IP packet has a format form with information of <hot swap, swap, ip1, ip2>. The access termination IP packet is a packet indicating that the hot swapping is to terminate the existing access network, wherein the 'hot swap' is a message indicating that the current hot swapping mode, and the 'swap' is a hot swapping The connection is terminated, ip1 represents the IP address of the first modem and ip2 represents the IP address of the second modem.

When the middleware of the first network receiving the multi-communication request IP packet transmits an acknowledgment (ACK) to complete handshaking, the hot swapping middleware instructs the modem control module to stop the operation of the first modem. .

In the above description of the present invention, specific embodiments have been described, but various modifications may be made without departing from the scope of the present invention. Therefore, the scope of the present invention is not to be determined by the embodiments described above, but will be apparent in the claims as well as equivalent scope.

1 is a diagram illustrating how hot swapping is performed when different wireless networks overlap each other according to an exemplary embodiment of the present invention.

2 is a block diagram illustrating a hot swapping apparatus for implementing hot swapping according to an exemplary embodiment of the present invention.

3 is a flowchart illustrating a process of performing hot swapping in software-based wireless communication (SDR) according to an embodiment of the present invention.

4 is a flowchart illustrating a process of acquiring an IP of a new second modem according to an embodiment of the present invention.

5 is a flowchart illustrating a process of performing multi-radio communication according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

20: hot swapping device 21: hot swapping middleware

22: modem control module 23: modem module

24: antenna module

Claims (8)

delete Hot swapping middleware that performs a modified connection in the network drives a new second modem in addition to the first modem that was previously communicating when a connection change occurs from the first network to the second network in SCA-compliant software-based wireless communication (SDR). A first step of obtaining an IP address of the second modem; A second step of simultaneously transmitting and receiving packets from the first network and the second network through the first modem and the second modem to perform multi-wireless communication; A third step of completing handoff by stopping driving of the first modem and transmitting and receiving a packet through only the second modem; Includes, the second step, Performing a handshaking notifying start of signal exchange between the second modem and the second network; The hot swapping middleware receives an IP packet (original IP packet) from an upper layer IP layer, and replaces the IP address of the first modem in the source address field with the IP address of the second modem in the original IP packet. Generating a duplicate IP packet by replacing an IP address of the first network with an IP address of the second network in a nation address field; Transmitting the original IP packet and the duplicated IP packet to a modem control module performing modem control; Step 2-4, wherein the modem control module delivers the original IP packet to the first modem and transmits the duplicated IP packet to the second modem to perform multi-wireless communication. Hot swapping method of the software-based wireless communication comprising a. The method of claim 2, wherein the first step, A modem control module performing modem control to establish a connection configuration with a second antenna by initializing the second modem according to an instruction of the hot swapping middleware; Obtaining, by the modem control module, an IP address of the second modem; Transmitting, by the modem control module, the obtained IP address to the hot swapping middleware Hot swapping method of the software-based wireless communication comprising a. delete The method of claim 2, wherein performing the handshaking step 2-1, Transmitting, by the hot swapping middleware, a multi-communication request IP packet informing of the multi-radio communication request to the second network according to an SCA standard; The second network receiving the multi-communication request IP packet transmits an ACK to the hot swapping middleware to complete handshaking. Hot swapping method of the software-based wireless communication comprising a. The method of claim 5, wherein the multi-communication request IP packet is a packet including information of <hot swap, parallel, ip1, and ip2>, wherein the 'hot swap' is a message indicating that it is currently in a mode for hot swapping. , 'parallel' is a message indicating that multi-communication will be performed at the same time, ip1 represents the IP address of the first modem and ip2 is the IP address of the second modem hot swapping method. The method of claim 2, wherein the third step, If it is determined that the connection between the first modem and the first network is to be terminated, the hot swapping middleware sending a connection termination IP packet to the first network requesting termination of the connection; The first network receiving the connection termination IP packet sends an ACK to the hot swapping middleware to complete the termination of the connection. Hot swapping method of the software-based wireless communication comprising a. The method of claim 7, wherein the connection termination IP packet is a packet including information of <hot swap, swap, ip1, ip2>, wherein the 'hot swap' is a message indicating that the current hot swapping mode, 'swap' 'Indicates a connection termination due to hot swapping, ip1 is an IP address of the first modem, ip2 is an IP address of the second modem.

Images