Abstract:
A very high data rate digital subscriber line (VDSL) modem. The VDSL modem comprises a plurality of first ports coupled to a plurality of local area networks, a second port coupled to a very high data rate digital subscriber line network, a flow control device coupled to the first ports, a transceiver coupled to the second port, a transmission device coupled between the transceiver and the flow control device, and a control device coupled between the flow control device and the transmission device to manage the flow control device and the transmission device.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates in general to a very high data rate digital subscriber line (VDSL) modem. In particular, the present invention relates to a VDSL modem with one VDSL port and several local area network (LAN) ports.  
           [0003]    2. Description of the Related Art  
           [0004]    Digital Subscriber Line technology architectures, generally denoted as xDSL, allow digital distribution of data services with traditional narrowband voice transmissions.  
           [0005]    One form of xDSL of particular interest to the present invention is very high data rate digital subscriber line (VDSL), a packet-based transmission architecture used to provide high bandwidth distribution of digital video and data signals to customers. The transmission capability of VDSL is higher than that of asymmetric digital subscriber line (ADSL) and cable modem.  
           [0006]    VDSL services are typically implemented in an asymmetric form having a maximum downstream transmission capability of about 52 Mbps over twisted pair. Upstream data rates in asymmetric implementations range to about 2.3 Mbps. Utilizing 10BaseS technology, the maximum downstream and upstream transmission capability of VDSL both range to 26 Mbps. The transmission capability of VDSL is ten times than transmission capability of ASDL, but the effective transmission distance of the local packets is less than 2000 meters. VDSL technology utilizes Frequency Division Duplexing (FDD) to separate downstram and upstream channel, and further, standard or so-called Plain Old Telephone Service (POTS)/ISDN in the frequency domain. VDSL technology utilizes high frequency bandwidth to transmit video signals and other data information requiring high-speed transmission, middle frequency bandwidth to transmit control signals, and low frequency bandwidth to transmit POTS packets. The transmission end modulates signals to different bandwidths through twisted pair and optic fiber nodes to the user end.  
           [0007]    A typical VDSL distribution system is similar to the typical ADSL distribution system. At the user end, it requires a modem to connect to the VDSL network. Typical telephone signals are transferred over a twisted-pair telephone line through a POTS coupler and splitter. High-definition television (HDTV), video on demand, and other video signals are transferred to the user end utilizing a VDSL upstream channel.  
           [0008]    [0008]FIG. 1 is a diagram illustrating the configuration of the VDSL modem in the prior art. As shown in FIG. 1, a typical VDSL modem  100  comprises a local area network (LAN) port  102 , a VDSL port  104 , a public switched telephone network (PSTN) port  106 , a transceiver  108 , a splitter  110 , a transmission device  112  and a packet processor  114 .  
           [0009]    The LAN port  102  is an Ethernet port coupled to the Ethernet  122 . The LAN port  102  receives local packets from Ethernet  122  and inputs them to the packet processor  114 . After processing the local packets, the packet processor  114  input them to transmission device  112 . The transmission device  112  controls the flow of the local packets to the splitter  110 . The splitter  110  is coupled to the VDSL port  104  and is also coupled to the PSTN port  106  through the splitter  110 . According the frequency of the local packets, the splitter  110  transmits the local packets to the VDSL network  124  through the VDSL port  104  or to the PSTN  126  through the PSTN port  106 .  
           [0010]    The PSTN port  106  is coupled to the transmission device  112  through the splitter  110 . The PSTN port  106  receives remote packets from the PSTN  126  and transmits them to the transceiver  108 . The VDSL port  104  receives remote packets from the VDSL network  124  and transmits them to the transceiver  108 . The transceiver  108  receives the remote packets from the PSTN port  106  and the VDSL port  104  and transmits them to the transmission device  112 . The transmission device  112  controls the flow of the remote packets from the transceiver  108 . The remote packets are through an error correction procedure in the transmission device  112 . Then, the remote packets are input to the packet processor  114 . The packet processor  114  transfers the remote packets to local packets that can be recognized by the Ethernet  122 . Then, the local packets are transmitted to Ethernet  122  through the LAN port  102 .  
           [0011]    The typical ADSL modem  100  usually has only one LAN port. Only one Internet connection device can be connected to the VDSL network through the ADSL modem  100 , an inconvenience for users. The user may use a notebook to connect to the VDSL network, and, at the same time, want to connect via video telephone through the VDSL network or to watch HDTV using a video on demand device to connect to the VDSL network. A need thus exists for a VDSL modem with several LAN ports to better serve the user.  
         SUMMARY OF THE INVENTION  
         [0012]    An object of the present invention is to provide a VDSL modem with one VDSL port and several local area network (LAN) ports for connection to a VDSL network through multiple devices at the same time.  
           [0013]    The very high data rate digital subscriber line (VDSL) modem of the present invention comprises a plurality of first ports, a second port, a flow control device, a transceiver, a transmission device, and a control device. The first ports are coupled to a plurality of local area networks. The first ports receive a plurality of local packets from the local area networks and output a plurality of remote packets to the local area network. The second port is coupled to a very high data rate digital subscriber line (ADSL) network. The second port receives the remote packets and outputs the local packets to the very high data rate digital subscriber line network. The flow control device is coupled to the first ports. The flow control device controls the flow of the local packets output from the first ports and distributes the flow of the remote packets to the first ports. The transceiver is coupled to the second port. The transceiver receives the remote packets from the second port and transmits the local packets to the second port. The transmission device is coupled between the transceiver and the flow control device. The transmission device receives the local packets from the flow control device, makes the effective transmission distance of the local packets become further through a process procedure, controls the flow of the remote packets transmitted from the transceiver, and transmits the remote packets to the flow control device through an error correction procedure. The control device is coupled between the flow control device and the transmission device to manage the flow control device and the transmission device.  
           [0014]    The local area networks of the present invention are Ethernet or Fast Ethernet. The first ports are Ethernet ports or Fast Ethernet ports. Each of the first ports is coupled to a video on demand device, a voice over Internet protocol device, a personal computer, a portable electronic device, or any other Internet connection device through an Ethernet line or a Fast Ethernet line.  
           [0015]    Furthermore, the very high data rate digital subscriber line (VDSL) modem further comprises a third port coupled between a public switched telephone network and the transceiver, and a splitter coupled between the transceiver and the first and second ports. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    The present invention can be more fully understood by reading the subsequent detailed description in conjunction with the examples and references made to the accompanying drawings, wherein:  
         [0017]    [0017]FIG. 1 is a diagram illustrating the configuration of the VDSL modem in the prior art;  
         [0018]    [0018]FIG. 2 is a diagram illustrating the configuration of the VDSL modem in the embodiment of the present invention; and  
         [0019]    [0019]FIG. 3 is a diagram illustrating the appearance of the VDSL modem in the embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0020]    The invention provides a VDSL modem with one VDSL port and several local area network (LAN) ports. At the same time, a user can use several Internet connection devices to connect a VDSL network through the VDSL modem. A video on demand device, a voice over Internet protocol device, a personal computer, a portable electronic device or any other Internet connection device may connect to local area network (LAN) ports through an Ethernet line or a Fast Ethernet line. Through the following description, the embodiments of the present invention can be understood in conjunction with the accompanying drawings.  
         [0021]    [0021]FIG. 2 is a diagram illustrating the configuration of the VDSL modem in the embodiment of the present invention. The VDSL modem  200  in the embodiment of the present invention is used in a system with 10BaseS technology. Utilizing 10BaseS technology, the maximum downstream and upstream transmission capability of VDSL will both reach 26 Mbps, and the effective transmission distance utilizing 10BaseS technology is between 1.35 and 2 kilometers. The VDSL modem  200  comprises four LAN ports  202   a ˜ 202   d , a VDSL port  204 , a PSTN port  206 , a transceiver  208 , a splitter  210 , a transmission device  212 , a flow control device  214  and a processor  216 .  
         [0022]    In the embodiment, the four LAN ports  202   a ˜ 202   d  are connected to different LAN systems. The LAN ports  202   a  and  202   b  are Fast Ethernet ports. The LAN ports  202   c  and  202   d  are Ethernet ports. Through one Fast Ethernet line (not shownn in FIG. 2), the LAN port  202   a  is coupled to a video on demand (VOD) system. Users of the VOD system can choose video information through the VDSL network. Through another Fast Ethernet line (not shown in FIG. 2), the LAN port  202   b  is coupled to a voice over Internet protocol (VOIP) system. VOIP utilizes an open network i.e. the VDSL network in the embodiment, to transmit voices and images, using packets. Through a telephone set, VOIP users can call each other anywhere, paying only network and local telephone bills. Through one Ethernet line (not shown in FIG. 2), the LAN port  202   c  is coupled to a personal computer  236 . Through another Ethernet line (not shown in FIG. 2), the LAN port  202   d  is coupled to a notebook  238 .  
         [0023]    As described above, the four LAN ports  202   a ˜ 202   d  are connected to different LAN systems. Each of the four LAN ports  202   a ˜ 202   d  receives a plurality of local packets from its LAN system and outputs the local packets to the flow control device  214 . The transmission capability to the flow control device  214  may be 10 Mbps or 100 Mbps. Thus, the flow control device  214  controls the flow of the local packets from the four LAN ports  202   a ˜ 202   d . Then, the flow control device  214  transmits the local packets to the transmission device  212 .  
         [0024]    The transmission device  212  receives the local packets from the flow control device and increases the effective transmission distance of the local packets. The procedure increases the effective transmission distance of the local packets to between 1.35 and 2 kilometers. Then, the transmission device  212  transmits the local packets to the transceiver  208 . The transmission device  212  also controls the flow of the local packets to the transceiver  208  and maintains the transmission capability to the transceiver  208  to be 12.5 Mbps.  
         [0025]    The transceiver  208  is coupled to the VDSL port  204  and also to the PSTN port  206  through the splitter  210 . According the frequency of the local packets, the transceiver  208  transmits the local packets to the VDSL network  224  through the VDSL port  204  or to the PSTN  226  through the PSTN port  206 . For example, POTS packets with voice signals are transmitted from the LAN port  202   b  to the PSTN  226  utilizing low frequency bandwidth. Control signal packets for controlling VOD system are transmitted from the LAN port  202   a  to the VDSL network  224  utilizing middle frequency bandwidth. Packets with data information requiring high-speed transmission are transmitted from the LAN ports  202   c  and  202   d  to the VDSL network  224  utilizing high frequency bandwidth.  
         [0026]    The PSTN port  206  is coupled to the transceiver  208  though the slipper  210  and receives remote packets from PSTN  226 . The remote packets may be packets with voice signals. The PSTN port  206  transmits the remote packets to transceiver  208 . The VDSL port  204  receives remote packets from the VDSL network  224  and transmits the remote packets to transceiver  208 . The remote packets may be packets with VOD signals or packets with data information requiring high-speed transmission. The transceiver  208  receives the remote packets from the VDSL port  204  and the PSTN port  206  and transmits them to the transmission device  212 . The transmission device  212  controls the flow of the remote packets from the transceiver  208 , and transmits the remote packets to the flow control device  214  through an error correction procedure. The error correction procedure comprises detecting a plurality of errors of the remote packets and recovering the errors. The flow control device  214  distributes the flow of the remote packets to the LAN ports. The flow control device  214  transfers the remote packets to local packets that can be recognized by the different LAN systems. Then, the local packets are transmitted to different LAN systems through different LAN ports according to their types. For example, packets with voice signals are transmitted to the LAN port  202   b . Then, through the Fast Ethernet line, the packets with voice signals are transmitted to the VOIP system  234 . Packets with VOD signals are transmitted to the LAN port  202   a . Then, through the Fast Ethernet line, the packets with VOD signals are transmitted to the VOD system  232 . Packets with data information requiring high-speed transmission are transmitted to the LAN ports  202   c  or  202   d . Then, through the Ethernet line, the packets are transmitted to the personal computer  236  or the notebook  238 .  
         [0027]    The processor  216  is coupled between the flow control device  214  and the transmission device  212  to manage the flow control device  214  and the transmission device  212 . The processor  216  detects whether the LAN ports  202   a ˜ 202   d  have errors or not. If the processor  216  detects an error, the processor  216  must take some action, such as stopping the operation of the LAN port that produces the error or recovering the error. The processor  216  also controls the flow control device  214  to set priority of the LAN ports  202   a ˜ 202   d  to provide instantaneous voice or video transmission. Thus, the VOD or VOIP service will have higher quality. In order to do so, typically, packets with voice or video signal have higher priority than packets with data information. Thus, the packets from the LAN ports  202   a  and  202   b  have higher priority than packets from the LAN ports  202   c  and  202   d . Furthermore, the processor  216  also controls the error correction procedure and the process procedure of the transmission device  212 .  
         [0028]    [0028]FIG. 3 is a diagram illustrating the appearance of the VDSL modem in the embodiment of the present invention. As shown in FIG. 3, the VDSL modem  300  of the present invention has four LAN ports  302   a ˜ 302   d , one VDSL port  304  and one PSTN port  306 .  
         [0029]    The four LAN ports  302   a ˜ 302   d  are connected to different LAN systems. Each of the four LAN ports  202   a ˜ 202   d  receives a plurality of local packets from its LAN system and transmits them to the VDSL modem  300 . The VDSL modem  300  transmits local packets to the VDSL network through the VDSL port  304  or to the PSTN through the PSTN port  306  according the frequency of the local packets.  
         [0030]    Furthermore, remote packets from the PSTN are received by the PSTN port  306  and are transmitted into the VDSL modem  300 . Remote packets from the VDSL network are also received by the VDSL port  304  and are transmitted into the VDSL modem  300 . The VDSL modem  300  transmits the remote packets to different LAN systems through different LAN ports according to the types of the remote packets.  
         [0031]    As described above, the VDSL modem provided by the present invention supports several LAN ports. Because a user can use several Internet connection devices to f through the VDSL modem, the VDSL modem can varied VDSL service at the same time.  
         [0032]    Finally, while the invention has been described by way of example and in terms of the preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements as would be apparent to those skilled in the art. Thus, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.