摘要:
In one embodiment, estimating a length of a network connection, determining whether the estimated network connection length deviates from a predetermined threshold range, modifying one or more signal characteristics when it is determined that the estimated network connection length deviates from the predetermined threshold range are provided.
摘要:
A local ISDN transmission system has a central base station and a number of subscriber radio terminals greater than the number of communication channels. The system is connectable to subscriber ports through an S.sub.0 wireless transmission interface and is responsive to an activation request from a subscriber radio terminal for opening any available and free communication channel for a communication. An intermediate generator in the base station and in each subscriber terminal divides an ISDN two-wire subscriber connection line between a line termination section and a network termination section communicating by radio transmission. The intermediate generator, upon the occurrence of an activation request by a subscriber terminal, allocates a communication channel within waiting and monitoring periods for the activation of the ISDN two-wire subscriber connecting line. A delay system delays the activation request by a delay period sufficient to switch the allocated communication channel and activate a radio system of the subscriber terminal.
摘要:
The present invention overcomes various problems by defining two upstream masks (U1, U2) and two downstream masks (D1, D2) and using a mask selectable system for the long reach digital subscriber line (LDSL), in which a unique modem feature is activated during handshake to automatically check for physical layer status in terms of spectral compatibility and, thus, automatically optimize the boosted mode with the use of the mask selectable system choose the best combination of upstream/downstream masks in any physical layer noise scenario.
摘要:
A system and method for extending the distance that xDSL services are able to be provided to subscribers. A DSLAM located at a Central Office is connected to a general-purpose network, such as the Internet. The DSLAM is additionally connected to a first fiber optic transceiver. The first fiber optic transceiver is connected via a fiber optic link to a second fiber optic transceiver located proximate to the subscribers' premises, preferably in a street cabinet. Each subscriber premise's equipment is connected to the broadband transceiver via subscriber lines. Electrical signals to be transmitted between the Central Office and the subscribers' premises are utilized to form a frequency division multiplexed signal. The frequency division multiplexed signal is used to modulate a light subcarrier for transmission across the fiber optic link. At the respective receiving transceiver, the frequency division multiplexed signal is reconverted to the electrical signals, which are then applied to the subscriber premises equipment or DSLAM, depending upon the direction of communication.
摘要:
The currently defined industry standard framing structure for 2B1Q ISDN signaling, at 160 kilobaud, provides 128 kbps for a customer (B1, B2) data channel, and 16 kbps for a data (D) channel. Of the remaining 16 kbps non payload bandwidth, 4 kbps are used for overhead maintenance data. Eight kbps of the remaining 12 kbps of non payload bandwidth, that customarily transport a repeated framing pattern, are usurped for the transport of an auxiliary compressed (from 64 KHz to 8 KHz) digitized voice POTS channel, that is sufficient to transport toll quality voice. The remaining framing pattern bandwidth is adequate prevent an unacceptable reduction in bit error rate.
摘要:
The transmission distance for DDS subscriber lines over a repeaterless four-wire link is extended to customer premises beyond the standard four-wire loop range of approximately 18 kft (56 kbps, 56 kbps with secondary channel capability, and 64 kbps) by employing commercially available ISDN transceiver chip hardware to multiplex a DDS data channel into quarter-rate (2B1Q) ISDN channels. At least one of a signalling channel and an out-of-band maintenance channel is used to convey differential delay compensation information, without modifying the framing structure of the transported channels, or requiring additional bandwidth for a separate framing channel.
摘要:
The range of digital data communication services, such as a basic rate 2B1Q ISDN channel, to customer premises located beyond the industry standard achievable range of a two-wire loop can be extended by increasing the capacity of the ISDN line code from two information bits per symbol to three information bits per symbol, so as to reduce the effective symbol rate, which is error correction encoded to an effective 4B1H line code for defining a sixteen level PAM signal waveform, and employing enhanced low signal-to-noise ratio signal processing techniques in both the transmitter and receiver to accommodate the increased insertion loss of the two-wire line resulting from its extended length. Such enhanced low signal-to-noise ratio signal processing techniques include a Tomlinson precoder in the transmitter, and an adaptive linear equalizer and a module unit in the receiver.
摘要:
One, or more, ISDN interfaces have their reach extended without violating ISDN interface standards by a method which converts ISDN coded information which is to be delivered over an extended channel into binary coded data prior to transmission, transmitting the binary coded information to a receiver at an extended location and there, after storage, and assembly, converting the binary coded data into ISDN specific coded data for delivery to an ISDN interface.
摘要:
The present invention overcomes various problems by defining two upstream masks (UI, U2) and two downstream masks (DI, D2) and using a mask selectable system for the long reach digital subscriber line (LDSL), in which a unique modem feature is activated during handshake to automatically check for physical layer status in terms of spectral compatibility and, thus, automatically optimize the boosted mode with the use of the mask selectable system choose the best combination of upstream/downstream masks in any physical layer noise scenario.
摘要:
A nullSmart DSL Systemnull for addressing the performance objectives of LDSL and examples of smart systems for LDSL are disclosed. In accordance with embodiments of the invention, there is disclosed a method for implementing smart DSL for LDSL systems. Embodiments of the method include presenting a number of spectral masks that are available on the LDSL system, and selecting from the number of spectral masks an upstream mask and a downstream mask wherein the upstream mask and the downstream mask exhibit complimentary features.