Patent Application
20060193336
The methods and systems of this disclosure relate to adapting cable television infrastructures to carry both video services and broadband network communication signals.
The ability to interconnect computers and other intelligent devices is a common requirement wherever people live and work today. The electrical connections required to form many local area network (LAN) communication systems have traditionally been accomplished by installing dedicated wiring both inside buildings and between clusters of buildings. A number of wireless (i.e. radio) methods have also been developed and deployed to address this need.
More recently, a power-wire based technology was developed to allow electric power wiring infrastructure to simultaneously transport electrical power and high-speed data. This technology, known as “Power Line Carrier” (PLC) technology, typically uses broadband Orthogonal Frequency Division Modulated (OFDM) signals between 2 MHz and 30 MHz to facilitate communication on power wiring.
Power Line Carrier technology offers a number of significant practical advantage over other available LAN-based technologies. For example, a PLC-based LAN can be installed in a house or other building without installing a single in-wall wire. Further, PLC-based LANS can cover a greater area than can available wireless LANS. Unfortunately, existing PLC-based LANs have a limited data bandwidth of about 14 million bits-per-second and are subject to interference by every appliance and device drawing power from a LAN's power lines. Accordingly, new methods and systems capable of providing in-building LANs are desirable.
In one aspect, a communication apparatus for implementing a broadband communication network using a cable-based television network installed in a building is disclosed, wherein the cable-based television network includes a video distribution device coupled to one or more coaxial cables, and wherein each coaxial cable can carry one or more downstream television broadcast signals and one or more upstream television control signals, the device includes a communications modem configured to transmit first communication signals over the one or more coaxial cables using a first allocated spectrum designed to avoid contention with ongoing upstream television control signals.
In a second aspect, a device for implementing a shared communication system over a cable-based television network installed in a building includes a broadband communication device coupled to the cable network and configured to transmit and receive first communication signals to/from the wired cable network via a coupling device, the first communication signals being allocated according to a spectral profile designed to avoid contention with upstream television control signals, wherein the first communication signals use a LAN protocol.
In a third aspect, a method for communicating over a demand cable television network, includes transmitting a broadband communication signal having embedded information onto the cable television network, the embedded information being derived from a signal provided by an Internet Service Provider (ISP), wherein the broadband communication signal is compliant with a local area network protocol, and where transmitting the broadband communication signal is designed to have no appreciable affect on cable television control signals residing on the cable network.
In a fourth aspect, a Local Area Network (LAN) includes a plurality of high-frequency broadband communication devices, wherein each communication device is coupled to a coaxial cable, and wherein the coaxial cable is capable of carrying separate and independent cable television control signals, wherein the broadband communication devices can communicate using a local area network protocol without interfering with the television control signals.
There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described or referred to below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Current technologies available to homeowners to create Local Area Networks (LANs) include various wireless technologies, such as Bluetooth and 802.11 networks, and Power Line Communication (PLC) networks, such as those provided by the HomePlug® standards. Unfortunately, both technologies have limited bandwidth, which can prove problematic in high-density housing and office settings.
However, many buildings (especially hotels and apartment) that have electrical wiring also have coaxial cable wires installed that might also be used to provide LAN services. While various broadband standards, such as Digital Subscribe's Line (DSL) have been adapted for use on coaxial cable, these technologies were developed for point-to-point communication/Wide Area Network (WAN) systems where design emphasis has been sending and receiving data over long distances in an upstream/downstream configuration. Additionally, these technologies are ill-suited for demand cable television systems due to frequency contention issues.
While the approaches depicted in
(A) Point-to-multipoint capability, which refers to the capability where a first device can simultaneously communicate with multiple other devices on a LAN. Compare direct point-to-multipoint capability, which refers to the capability where a first device can simultaneously communicate with multiple other devices on a LAN without intervention of an intermediate device, such as a network hub. Also compare Specific-frequency point-to-multipoint capability, which refers to the capability where a first device can simultaneously communicate with multiple other devices on a LAN using a particular carrier frequency. Contrast this capability with the various DSL standards, which generally allow only point-to-point communication. While there are some DSL standards that are partially point-to-multipoint from the standpoint that an upstream device can simultaneously communicate with multiple downstream devices, such communication is limited in that the upstream device maintains communication with each downstream device using separate carrier frequencies in a Discrete Multi-Tone (DMT) environment.
(B) Digital encryption, such as the Digital Encryption Standard (DES) or triple Digital Encryption Standard (3DES or DES3). Presently, DSL and other known WAN standards do not use or need such capability.
(C) An Orthogonal Frequency Division Multiplexing (OFDM) format, which helps to increase data bandwidth while decreasing the effects of multi-path signal distortion. While various DSL protocols use a signal format having similarities to OFDM known as DMT, OFDM has a number of advantages over DMT, such as the need for but a single modem.
(D) A contention protocol, such as Carrier Sense Multiple Access/Collision Detection (CSMA/CD), Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) and Token Passing. The CSMA/CD is a popular protocol that is both fast and commonly used. Examples of networks using CSMA/CD include Ethernet and 100baseT networks.
While the CSMA/CA protocol is not as fast as the CSMA/CD protocol, CSMA/CA has an advantage in that it provides for the “hidden node” problem. The hidden node problem occurs in a point-to-multipoint network having at least three nodes, e.g., Node A, Node B and Node C. It may be possible that in certain cases Node B can hear Node A (and vice versa) and Node B can hear Node C (and vice versa) but Node C cannot hear Node A. That is, Nodes A and C are effectively hidden from one another. In such an environment both Node A and Node C could both properly transmit a packet simultaneously in a CSMA/CD environment since they cannot hear each other on a ‘listen’ phase, but the result is that Node B would get corrupted data. However, unlike a CSMA/CD protocol, a CSMA/CA protocol could prevent Nodes A and C from simultaneously transmitting (with resulting data corruption).
(E) Full spectral bi-directionality, which for the purpose of this disclosure means that almost any device coupled to a network can both receive and transmit information using all or substantially all of an available communication bandwidth. For example, the POTS, ISDN and SHDSL technologies shown in
(F) Error Detection and/or Error Correction, which may include Cyclic Redundancy Coding CRC), Forward Error Correction (FEC), Block coding (such as BCH) or any other existing or later developed error detection or correction technology.
(G) Packet Transmission, which infers that data is transmitted in discrete packets.
(G) Burst Transmission, which infers that data is transmitted in discrete bursts, i.e., the carrier signal is silent when there is no communication.
(H) Hub-and-Spoke Topology, which refers to a widely-known communication topology where a central hub is used to receive and retransmit data.
(H) Hub-Versatile Topology, which refers to a topology where various terminals may optionally use a hub to communicate or may opt to communicate directly with one another.
(H) Daisy-chain Topology, which refers to a widely known topology where data is passed from one terminal to another, then to another until the intended destination terminal receives the transmitted data.
In operation, the cable network 510 can be used to transport television signals from the cable service provider 530 to consumers (located at the client access points 540-546). When a client access point 540-546 is in communication with the cable service provider 530, the television signals would, of course, be relayed/transmitted/received via the external access equipment 532 and coupler 512
Simultaneously, the cable network 510 can be used to transport various broadband signals, such as HomePlug compatible (or other LAN signals) both between client access points 540-546 and to/from individual client access points 540-546 and an external device or system, e.g., a specific communication node on the ISP 520. When a client access point 540-546 is in communication with the ISP 520, the broadband signals would, of course, be relayed/transmitted/received via the LAN gateway 522 and coupler 512.
As discussed above, in addition to the television and LAN signals, the cable network 510 might also be used to convey WAN signals to and from an external WAN node via the WAN coupler 592. Additionally, Integrated Services Digital Network (ISDN) or Symmetric High-speed DSL (SHDSL) communication signals might be simultaneously transmitted over the cable network without interference of both television and Homeplug (or HomePNA) signals.
Also as discussed above, in various embodiments, it may be desirable to reconfigure the spectral profile of upstream cable television signals rather than reconfigure the spectral profile of the LAN signals. In either case, such reconfiguring might be accommodated using optional link 502 between the gateway 522 and the television external access equipment 532. For example, before the gateway 522 goes online, the gateway 522 and the television external access equipment 532 can share spectral information and allow for one or the other to reconfigure.
The exemplary cable network 510 consists of one or more pairs of coaxial cables commonly used for cable television purposes and interconnected using various connectors and splitters/combiners also commonly used for cable television. However, it should be appreciated that the particular physical makeup of the cable network 510 can take any combination of electrical forms as long as such form is amicable to high-frequency signals
The external access equipment 532 of the present example of
The gateway 522 of the present example of
While some network developers have attempted (with limited success) to bypass this limitation by relying on a small amount of “leakage” inherent in splitters or using sufficiently low frequencies where splitters behave differently, these approaches are generally unsuitable for high-speed communication. Accordingly, the inventors of the disclosed methods and systems have employed an upstream gateway that would be in the operable data path for various client access points as a repeater. For example, while client access point 540 could not directly communicate with client access point 542, messages between the two client access points 540 and 542 could easily be relayed to one another via a gateway (or other device) upstream relative to both client access points 540 and 542.
Although the exemplary gateway 522 uses a bussed architecture, it should be appreciated that any other architecture may be used as is well known to those of ordinary skill in the art. For example, in various embodiments, the various components 610-690 can take the form of separate electronic components coupled together via a series of separate busses.
Still further, in other embodiments, one or more of the various components 610-690 can take form of separate servers coupled together via one or more networks. Additionally, it should be appreciated that each of components 610-690 advantageously can be realized using multiple computing devices employed in a cooperative fashion.
It also should be appreciated that some of the above-listed components can take the form of software/firmware routines residing in memory 620 and be capable of being executed by the controller 610, or even software/firmware routines residing in separate memories in separate servers/computers being executed by different controllers. Further, it should be understood that the functions of any or all of components 630-640 can be accomplished using object-oriented software, thus increasing portability, software stability and a host of other advantages not available with non-object-oriented software.
Further, while the exemplary secondary network interfaces 690 are a combination of devices and software/firmware configured to couple computer-based systems to the Internet over an electrically wired line using an ethernet protocol, it should be appreciated that, in differing embodiments, the secondary network interfaces 690 can take the forms of modems, networks interface card, serial buses, parallel busses, WAN or LAN interfaces, wireless or optical interfaces, any number of distributed processing networks or systems, a virtual private network device, Token Ring, a Fiber Distributed Datalink Interface (FDDI), an Asynchronous Transfer Mode (ATM) based system, a telephony-based system including Ti and El devices, a, a wireless system and the like as may be desired or otherwise dictated by design choice.
In operation, an operator can first couple one or more of the secondary interfaces to a number of external devices, such as an ISP connection and perhaps equipment related to a cable television provider. The operator can then couple the primary network interface 680 to a coaxial cable or other physical medium carrying television signals.
Next, the operator can program the gateway 522 to transmit and receive according to a specific spectral profile in order to avoid signal contention between the gateway 522 and any resident television-related signals.
In a first mode of operation, the gateway 522 can receive such spectral information/instructions via an external source via an operator. This mode assumes that the operator can either determine the used and available frequency spectra via testing or using some other technique, such as by inspecting the relevant television equipment, reviewing the appropriate equipment logs, requesting the information from a cable television provider, etc.
In a second mode of operation, the gateway 522 can receive such information directly from the relevant television equipment via one of the secondary network interfaces 690. Alternatively, such information may be taken from a computer-based device containing a database of such information.
In a third mode of operation, the gateway 522 can receive such information by performing certain tests directly on the television cable (or other physical medium) via the primary network interface 680. In this mode, operation starts by using the data acquisition device 684 of the PHY 682 to record significant activity at certain frequencies of interest. For example, if the gateway 522 were using 256 frequencies equally spaced between 5 MHz and 25 MHz to communicate, the data acquisition device 684 (which can be any combination of filtering, frequency shifting, digitizing and other electronic devices) could digitally sample about each frequency of interest and store the data in memory 620.
Next, spectral usage determining device 630 can analyze the stored data using any number of available techniques, e.g., Fourier transforms, to determine whether each frequency of interest is being used by other (non-LAN) equipment. Once these determinations are made, the spectral usage information (whether internally determined or provided by an external source) is sent to the spectral allocation device 640, which can then allocate the spectral profile available to the gateway 522 also taking into account the need for guard-band between television signals and gateway signals as well as other considerations of interest. The allocate the spectral profile information is then programmed into the primary network device 680, which in turn can then be activated so that it can communicate with other LAN-based devices without interfering with television-related signals.
Again as discussed above, in an alternative mode of operation, instead of programming primary network device 680, the exemplary gateway 522 can communicate with various pieces of television equipment in order to request that such equipment reassign its used spectra above that used by the gateway 522, but within the specified range, e.g., between 21 MHz and 50 MHz for Homeplug 1.0. In situations where some, but not all, of such used spectra can be reassigned, the gateway 522 can still benefit by using a combination of cable television reassignment and LAN spectral allocation techniques to substantially maximize the available communication bandwidth.
Once the spectral profile for the gateway 522 is established, such information may be made available to other devices via the available cable network using a special protocol, or such information may be programmed into the other devices before installation, manually after installation and so on.
However, in certain circumstances where a substantial connectivity between two sub-networks is required, the isolation depicted in
In step 906, the spectral profile for the communication device and/or the relevant television equipment is reassigned/reallocated to avoid contention issues. Next, in step 908, communication between the gateway and various client access points can commence. Control then continues to step 950 where the process stops.
In step 1008, the transmitted LAN signals are then coupled from the first coaxial cable onto a second coaxial cable of the cable-based television network. As discussed above such coupling can be made possible via an appropriate coupling device or combiner/splitter. Next, in step 1010, the transmitted LAN signals can be further distributed onto multiple coaxial cables. Control continues to step 1012.
In step 1012, the LAN signal can be received by each intended recipient on the second coaxial cable. Next, in step 1014, the received LAN signals can be appropriately converted. Then, in step 1016, the converted signals are transmitted to a targeted receiving device. Control then continues to step 1050 where the process stops.
In step 1108, information contained in the received signal is extracted. Next, in step 1110, the ultimate/desired destination of the LAN signal is determined based on a portion of the extracted information. Then, in step 1120, a determination is made as to whether the desired destination is local, i.e., coupled to the cable television network. If the desired destination is local, control continues to step 1122: other wise, control jumps to step 1130.
In step 1122, the information extracted in step 1110 is repackaged and transmitted in a downstream LAN signal. Next, in step 1144, the downstream LAN signal is transported downstream through the appropriate cables and coupled through the appropriate couplers. Then, in step 1126, the downstream LAN signal is received by the intended device. Control continues to step 1150 where the process stops.
In step 1130, the information extracted in step 1110 is repackaged and transmitted off-network to an ISP or another network. Control continues to step 1150 where the process stops.
In various embodiments where the above-described systems and/or methods are implemented using a programmable device, such as a computer-based system or programmable logic, it should be appreciated that the above-described systems and methods can be implemented using any of various known or later developed programming languages, such as “C”, “C++”, “FORTRAN”, Pascal”, “VHDL” and the like.
Accordingly, various storage media, such as magnetic computer disks, optical disks, electronic memories and the like, can be prepared that can contain information that can direct a device, such as a computer, to implement the above-described systems and/or methods. Once an appropriate device has access to the information and programs contained on the storage media, the storage media can provide the information and programs to the device, thus enabling the device to perform the above-described systems and/or methods.
For example, if a computer disk containing appropriate materials, such as a source file, an object file, an executable file or the like, were provided to a computer, the computer could receive the information, appropriately configure itself and perform the functions of the various systems and methods outlined in the diagrams and flowcharts above to implement the various functions. That is, the computer could receive various portions of information from the disk relating to different elements of the above-described systems and/or methods, implement the individual systems and/or methods and coordinate the functions of the individual systems and/or methods related to communication services.
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
