« ZurückWeiter »
6 Wideband Modem [W05 210/7
Wideband _ Switch Duplexer Control |— Vlfideband
RX H H Channel H RX
227 Diplexer 228
0--vo L I—— H Home Coaxial L
Network I_ TX
TX ~ J L L L K
\ \ J \ \
237 Modem A 238 Modern B
ControI CATV Duplexer
Signal Reverse CATV Forward Modem A Transition Modem B 215
Band Band (not to scale) TX Band TX
Lfi/—J H—J Frequency
250 Low 216 High 217 F ' 2
Transition Bands Band\/ Band\/ .
910 z mus zmz ‘0I 1191‘ luewd ‘Sn
L H Diplexer 300 Reverse TX 308 -J T T T U U U N N N E E E R R R 1 2 3
310 J \ 320 \ 330
U.S. Patent Jan. 10,2012 Sheet 4 of5 US 8,094,640 B2 Coaxial Cable \/ K 305 CATV Forward Band! L30 L H Reverse Band Diplexer l—_ /“ 405 L H Mod-em/HCT Diplexer 234 V K L H Duplexer H L K 230 K /415 6 ti Band-Select T T Switch U U RX Switch N N E E R R 225 1 2 K 310 -J 320 J 5 Wideband 410 TX N / E R 3 K 245 Control ' RX Reverse TX \ 420
1 FULL DUPLEX WIDEBAND COMMUNICATIONS SYSTEM FOR A LOCAL COAXIAL NETWORK
This patent application is a continuation-in-part of copending U.S. patent application Ser. No. 10/342,670 filed Jan. 15, 2003.
This invention relates in general to broadband communications systems, and more particularly, to the field of a full duplex wideband communications system operating within a local coaxial network.
DESCRIPTION OF THE RELATED ART
Subscriber premises receiving cable television or satellite service typically have a coaxial network for providing received signals to various rooms in the premises. The coaxial network typically connects set-top terminals (STT) for decoding the signals (e.g., cable or satellite television (CATV) signals) to a communications system. It will be appreciated that other equipment, such as cable modems and video recorders, to name a couple, can also be connected to the coaxial network. The transmitted signals may be, therefore, video/audio signal, telephony signals, or data signals.
Traditionally, an individual STT could not communicate with the other networked STTs; they were receiving devices that may have had the capability to transmit data to a headend facility in the system. As technology progressed, a server STT could communicate with a plurality of remote STTs in a network. This communication is desirable in that the server STT could share files or programs with the remote STTs upon command from the remote STT. By way of example, the server STT may contain storage media, such as hard disk drives, to store video programs. Accordingly, the networked remote STTs may want to view those stored programs. In this manner, upon request, the server STT can transmit a program to the requesting remote STT for viewing at that STT. Further information regarding a networked multimedia system that includes a server and remote STTs can be found in copending U.S. patent application Ser. No. 10/342,670 filed Jan. 15, 2003, the disclosure and teachings of which are hereby incorporated by reference.
A need exists, however, for systems and methods that improve upon communications among networked equipment in a subscriber premises.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, emphasis instead being placed upon clearly illustrating the principles of the invention. In the drawings, like reference numerals designate corresponding parts throughout the several views.
FIG. 1 illustrates a block diagram of a coaxial network 100 that includes a plurality of STTs for receiving and decoding CATV signals.
FIG. 2 illustrates a block diagram of two networked modems and a frequency range plan that are suitable for employing the full duplex wideband communications in accordance with the present invention.
FIG. 3 illustrates a simplified block diagram of the RF portion of a set-top terminal.
FIG. 4 illustrates a simplified STT including a wideband modem in accordance with the present invention.
FIG. 5 is a graph illustrating a frequency response of a wideband modem in a coaxial network having a multipath environment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Preferred embodiments of the invention can be understood in the context of a broadband communications system and a local network. Note, however, that the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. For example, transmitted broadband signals include at least one of video/audio, telephony, data, or Internet Protocol (IP) signals, to name but a few. Devices included in the broadband communications system for receiving the transmitted broadband signals may include a set-top terminal (STT), a television, a consumer electronics device such as a DVD player/ recorder, a computer, a personal digital assistant (PDA), or other type of electronics device. Furthermore, in accordance with the present invention all of these receiving devices may include a modem or be connected to a stand-alone modem for receiving high speed data. All examples given herein, therefore, are intended to be non-limiting and are provided in order to help clarify the description of the invention.
The present invention is directed towards a full duplex wideband communications device and system that are suitable for use in a coaxial network. The coaxial network is typically confined to a subscriber premises. It will be appreciated, however, that the network can also be used in a multiunit dwelling, business, school, hotel, or hospital, among others. Advantageously, the present invention allows for full duplex wideband communications among STTs or modems that are connected in the coaxial network. The communications between any pair of STTs (e.g., a server STT and a remote STT or two remote STTs) are at data rates suitable for high definition video transmissions. The present invention also allows multiple STTs to share the network without interference with each other. Additionally, a STT, for example, the server STT, is capable of providing different content to different remote STTs concurrently. Furthermore, the communication between STTs and the reception of conventional CATV signals occur simultaneously without interference to the received CATV signals. As mentioned, the modem can be a standalone device that is connected to an STT and still utilize the full duplex wideband communications in accordance with the present invention.
FIG. 1 illustrates a block diagram of a coaxial network 100 that includes coaxial cables 105 and power splitters 106. The coaxial network 100 is designed to connect set-top terminals (STTs) 110a-n within the premises to the CATV communications system. In the coaxial network, the STTs 110a-n (or other devices connected to the network 100) should preferably be able to communicate with each other. However, there is high loss between the STTs 110a-n due to port-port isolation of the splitters 106. To reduce the loss between the STTs 110a-n, a reflector 120 is inserted between the coaxial network 100 and the CATV communications system. The reflector 120 contains one or more band-rej ect filters that are centered on frequencies used to communicate between the STTs 110a-n. The filters reflect signals at these frequencies with low loss, so that the loss between STTs is minimized. Additionally, the band reject filters prevent the in-home signals