Abstract: A system, device, and method for evaluating dynamic range in a communication system utilizes a narrow band multiple tone test signal for emulating a wide band composite signal equivalent to the symbol rate bandwidth of a digitally modulated carrier. The multiple tone test signal is constructed such that a significant portion of the third order intermodulation distortion products fall within the channels adjacent to the test channel so that the dynamic range can be evaluated with a commercially available industry standard CATV analyzer using a standard adjacent channel power measurement technique.

Abstract: A device and method for detecting digital impairments affecting an upstream pulse code modulation (PCM) channel in a digital communication network, involves: receiving, by a digital PCM modem interconnected to the digital communication network, a random sequence of digital values selected from a constellation of digital values transmitted over the upstream PCM channel of the digital communication network; establishing distributions of the received digital values, each distribution corresponding to one of a plurality of time intervals; and deriving from the distributions the types of robbed bit signaling and digital loss affecting the upstream PCM channel of the digital communication network for each time interval.

Abstract: The apparatus (101) and method for spectrum management in a multipoint communication system controls upstream channel usage for secondary stations (110) transmitting information to a primary station (101) and downstream channel usage for secondary stations (110) receiving information from a primary station (101). The preferred apparatus (101) embodiment includes a processor arrangement (120) having a master controller (121) and a plurality of processors (130), with the processor arrangement connected to a channel interface (125). The apparatus (101) and method controls channel load balancing, channel congestion, and channel assignment in a multipoint communication system, and controls upstream channels independently from downstream channels. Factors and parameters utilized in such channel control and allocation include error parameters, channel noise parameters, transmit and receive loading factors, and congestion parameters.

Abstract: A system, device, and method allowing a host device to communicate with, and initialize, an uninitialized peripheral device includes, on the peripheral device, logic for storing a separate mask corresponding to each of a plurality of memory locations, and logic, responsive to a request for reading a memory location, for outputting a bit-wise exclusive-OR of data stored in the memory location and the corresponding mask. The mask is equal to a bit-wise exclusive-OR of a predetermined configuration value and a preset value. Thus, if the memory location is not pre-programmed with configuration information, the bit-wise exclusive-OR of the data stored in the memory location and the corresponding mask results in a valid default configuration value. Once the host device is able to communicate with the peripheral device, the host device programs the peripheral device by storing in the memory location a new data value equal to the bit-wise exclusive-OR of a new configuration value and the corresponding mask.

Abstract: A system, device, and method for improving access in a hybrid contention/polling protocol maintains a list of active users, a list of recently active users, and a list of inactive users. An active user that becomes inactive is moved into the list of recently active users, and a recently active user that remains inactive is moved into the list of inactive users. A limited contention poll addressed to a number of inactive users and at least one recently active user authorizes any of the addressed users to contend for access to the shared channel. Upon detection of a collision, addressed users that are in the list of recently active users are polled individually, while the inactive users are sent a collision resolution poll which forces the inactive users to contend again for access. Users that become active are moved into the list of active users.

Abstract: A system, device, and method for contention-based reservation in a shared medium network resolves collisions resulting from contention access using a combination of probabilistic tree splitting and first-come-first-served splitting techniques. The collision resolution procedure utilizes the first-come-first-served splitting technique to select a collision resolution interval, and provides two contention mini-slots to improve the likelihood of successful reservations. Each contending user transmits a reservation request in a randomly selected contention mini-slot. Two contention mini-slots are provided for a predetermined maximum number of collision resolution iterations, after which only one contention mini-slot is provided.

Abstract: A multimedia file and method for forming the same organize instances of multimedia information according to media information type (e.g., audio, video, MIDI, etc.), encoding format, media subtype, and encoding rate. Several instances of the same media information type are included, each of such instances having a different encoding format, media subtype, and/or encoding rate. A presentation application utilizes the subject multimedia file to identify, select, and present specific instances of the multimedia information, permitting the presentation application to customize a multimedia presentation based on, among other things, the rate of the connection from the presentation application to the presentation consumer and the decoding capabilities of the presentation consumer.

Abstract: A system (800), device (820), and method (600, 700) for aggregating MAC users in a shared medium network improve MAC performance and minimize complexity of a headend scheduler by aggregating a number of MAC Users into an Aggregate MAC User. The Aggregate MAC User acts as a proxy for its Constituent MAC Users by contending for network resources on behalf of the Constituent MAC Users and allocating network resources to the Constituent MAC Users as needed.

Abstract: The present invention provides a system (100), device (400, 500) and method (600, 700) for forward error correction (FEC) coding and interleaving in a variable length burst transmission communications system. The system incorporates at least one shortened FEC encoder to accomplish FEC coding and burst interleaving for transmission from a variable length burst data source. Decoding/de-interleaving is accomplished by a device consisting of at least one fixed length FEC decoder. The technique of padding with zero symbols at the end of burst is used in the device to allow decoding with fixed length FEC decoders and for minimizing delay.

Abstract: A system, device, and method for sharing contention mini-slots among multiple priority classes determines an aggregate feedback state for each of the priority classes, determines a preferred allocation of contention mini-slots for each of the plurality of priority classes using the aggregate feedback state, and determines an actual allocation of contention mini-slots for each of the plurality of priority classes using the preferred allocation. The actual allocation of contention mini-slots is determined by making a preliminary allocation for each of the priority classes based on the preferred allocation and then allocating any remaining contention mini-slots among the priority classes.

Abstract: A system and device for, and method of, detecting, characterizing, and mitigating deterministic distortion in a communication system. An exemplary communication system includes a digital adaptor for sending octets on to a backbone of a PSTN, which then sends, and potentially distorts the octets, received by a line interface. The line interface converts the octets to baseband signals received by an analog adaptor. Several mechanisms and methods are described in which the analog and digital adaptor cooperate to detect the presence of distortion, in particular, robbed bit signaling, on the communication system. The characterization may then be used to mitigate the effects of the distortion. Several receive constellations are provided, each constructed in view of the transmit constellation and in view of the manner in which the deterministic distortion will distort signals transmitted over the system. The receive constellations differ from the transmit constellation.

Abstract: A system (400) and apparatus (200, 300) for, and method (100) of, interfacing a demodulator and a forward error correction decoder enables a forward error correction decoder to be used in conjunction with an otherwise incompatible demodulator. Data received from the demodulator having a first encoding and formatted as M bits per baud at a first baud rate is encoded into data having a second encoding. The data having the second encoding is output to the forward error correction decoder as N bits per baud at a second baud rate as required by the forward error correction decoder.

Abstract: The apparatus (101, 110) and method for authentication is provided by generating R and encrypting it using a selected algorithm K as the key in a primary station, encrypting the verification key, V using R as the key and encrypting the result using K as the key, transmitting both pieces of information (VAR1 and VAR3) to the secondary station (110), using K to decrypt VAR1 and VAR3 to obtain R and eventually V which is encrypted using R in the secondary station (110)verifying authenticity of the primary station (101) if the decrypted V matches the secret key portion of V that is stored at the secondary station (110).

Abstract: A cell based network (100) for transmitting ATM user cells (118), including ABR data cells (118.sub.D) and forward control, or RM, cells (118.sub.FRM) at predetermined cell rates from at least one user source (102) in a virtual connection (VC, 110) through at least one ATM switch (120) and at least one transmission link (130) in the network to at least one user destination (104), employs a method and apparatus for controlling a user source (102) transmission cell rate in the presence of congestion in the VC (110). The calculation of a Fair Share cell transmission rate is written into a backward control, or RM, cell (118.sub.BRM) optionally takes place only in the presence of congestion at an ATM Switch (120). The calculation of the Fair.sub.-- Share value is simplified and calculation time is shortened by changing the number of active ABR VCs (N.sub.ABR) to a factor of two (E.sub.NABR) and dividing the maximum cell transmission rate by E.sub.NABR.

Abstract: An apparatus (101, 110) and method for channel acquisition in a communication system (100) provides for selecting a channel, from a multiplicity of available channels (205), and determining whether the selected channel is the properly assigned channel for data and other information to be received by the apparatus (101, 110). The selected channel is monitored for a predetermined or adaptive energy level (210), a predetermined modulation mode (215), for a protocol signal, and for a protocol signal having an identification specifying the particular apparatus (225), such as a protocol frame containing a serial number corresponding to the apparatus. When a protocol signal having an identification specifying the particular apparatus (225) is received, the selected channel is acquired (250) for reception of data and other information.

Abstract: A control station (8) is coupled to a plurality of tributary devices (20, 16, 18) by way of at least one high speed broadcast downstream data channel and more than one shared lower speed upstream data channels. The control station (8) broadcasts data to all the tributary devices (20, 16, 18) and selects a channel for a specific tributary device (20, 16, 18) to respond to a poll. After polling, the tributary device (20, 16, 18) changes the tributary device transmitter (42) to the frequency of the selected channel. The tributary device (20, 16, 18) either sends data to send to the control station (8) or sends a negative acknowledge to the control station (8). If a negative acknowledgment was transmitted, the control station (8) notifies the control station transmitter that the channel is idle.

Abstract: A plurality of secondary stations (10.sub.a through 10.sub.n) are coupled to a primary station (8) by way of a shared communication medium (15, 16). The secondary stations (10.sub.a through 10.sub.n) sends information to the primary channel on the upstream channel. The primary station sending information to the secondary stations (10.sub.a through 10.sub.n) on a downstream channel. The power level of a secondary station (10.sub.n) is set at the power level stored in secondary station memory (55). The secondary station (10.sub.n) transmits a message to the primary station on the upstream channel. The primary station (8) receives the message, determines the power level of the received message, and sets the power level of the secondary device to the nominal power level.

Abstract: An apparatus and method to implement a hybrid contention and polling protocol for a communications or computer network is disclosed.

Abstract: The event scheduler (100; 200) and method (300) of the present invention solve the problem of mixing multiple service categories on the same physical link or media by utilizing a calendar queue scheduling method (i.e., based on prior actual transmission times of previous packets). The event-driven cell scheduler is, for example used in an asynchronous transfer mode ATM network and may, for example, be embodied in software, hardware and firmware.

Abstract: A method (1200, 1500, 1600, 1700, 1800) and packet switch (500, 600, 700, 1400,1900, 2000) for efficient switching of a plurality of received packets from a plurality of ingress ports to a plurality of egress ports, using the steps of: A) storing the packets in memory; B) sending arrival information for each packet to a destination egress port for the packet; C) storing, in memory at each destination egress port, the arrival information; D) requesting, by each destination egress port, the packets from the packet memory in accordance with a predetermined scheme; and E) sending, by the packet memory, to the destination egress ports, the packets requested.