Motorola Corporation

Codex Corporation

Stephen Schroeder

John A Perreault

Mete Kabatepe

Abhay Joshi

Lawrence W Lloyd

Michael Jaimie Cooper

Manickam R Sridhar

Krishnan Ramakrishnan

Jeffrey T Klayman

Richard C Wade

Katherine A Unger

Keith M Conger

An adaptive and dynamic forward error correction scheme for a communication channel is disclosed. The method and apparatus calculates the actual bit error rate for comparison with a target bit error rate. When a channel is performing better than required by the performance specifications, the forward error correction power can be reduced to provide greater throughput. If the calculated actual bit error rate is greater than the target bit error rate, then the forward error correction power is increased in an attempt to lower the calculated bit error rate. A feedback loop is employed to continually calculate revised bit error rates as the forward error correction power is increased or decreased.

Apparatus and method for providing optimal adaptive forward error correction in data communications

In a system, device, and method for selecting a channel from among a plurality of channels, a number of available channels are selected for testing. A channel quality measurement is made for each of the number of available channels. The channel having the best channel quality measurement is then selected. To make the channel quality measurements, a primary station selects a channel to be tested and also selects a secondary station with which to perform the test. The primary station transmits a control frame to the selected secondary station, including a channel identifier identifying the selected channel. Upon receiving the control frame, the selected secondary station adjusts its transmitter to the selected channel based on the channel identifier in the control frame, and transmits a reference signal on the selected channel. Meanwhile, the primary station adjusts its receiver to the selected channel and receives the reference signal from the selected secondary station. The primary station then measures the quality of the received reference signal.

System, device, and method for selecting a channel in a multichannel communication network

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.

Hybrid contention/polling access method

An apparatus and method to implement a hybrid contention and polling protocol for a communications or computer network is disclosed. Various apparatus and method embodiments of the invention employ specific polls from a primary station for polling identified secondary stations of the network which may be in an active state, general polls to any of a plurality of secondary stations of the network which may be in an unresponsive state to initiate contention access to the network, and general polls for collision resolution in the event that a plurality of secondary stations may simultaneously contend for network access. Various embodiments may also include frequency channel allocation for transmission and reception of data and other information within the network. The various procedures and apparatus disclosed may also be used to apply various polling parameters to optimize network performance.

System for determining the frequency of repetitions of polling active

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.

Method, device and data communication system for multilink polling

An apparatus and method to implement a hybrid contention and polling protocol for a communications or computer network is disclosed. Various apparatus and method embodiments of the invention employ specific polls from a primary station for polling identified secondary stations of the network which may be in an active state; limited contention polls to an identified individual secondary station which may be in an idle state or to an identified subset of a plurality of secondary stations which may be in an idle state to initiate limited contention access to the network; limited contention polls for collision resolution in the event that a plurality of secondary stations in an idle state may have simultaneously contended for network access; general polls to any of a plurality of secondary stations of the network which may be in an unresponsive state to initiate contention access to the network; and general polls for collision resolution in the event that a plurality of secondary stations may simultaneously contend for network access. Various embodiments may also include frequency channel allocation for transmission and reception of data and other information within the network.

Method and apparatus for a hybrid limited contention and polling protocol

An apparatus (101, 110) and method for adaptive forward error correction in a data communication system (100) provides for dynamically changing forward error correction parameters based upon communication channel conditions, such as noise levels or error rates. In the method embodiment of the invention, data having a current degree of forward error correction is received (305), and a channel parameter is monitored (310), such as packet or bit error rates. A threshold level for the channel parameter is determined (315), and the monitored channel parameter is compared to the threshold level (320). When the channel parameter is not within a predetermined or adaptive variance of the threshold level, a revised forward error correction parameter having a greater or lesser degree of forward error correction capability is selected (330, 340, 350, 360), and the revised forward error correction parameter is transmitted (370). The device receiving the revised forward error correction parameter, such as a secondary station (110), then transmits data encoded utilizing the revised error correction parameter (425).

Apparatus and method for adaptive forward error correction in data

The system and method provide for efficiently resolving collisions in an environment where a transmitting device cannot hear collisions without a headend control station/control device, i.e., master, repeating transmission of all upstream frames in the downstream direction. This invention also prevents additional collisions from occurring between a device that is retransmitting and a device that is transmitting a packet for the first time. Further, the present invention allows continued utilization of a channel by other devices while contending devices are processing collision resolution procedures.

System and method for hybrid contention/polling protocol collison

A method and system provide efficient resolution of transmission collisions in a simultaneous channel access communication environment. At least a first Master device and a plurality of Slave devices utilize the steps of: (1) transmitting, by the plurality of Slave devices upon receiving a contention poll from the first Master device, information to the Master device, wherein transmissions of the Slave devices provide a collision; (2) selecting a subset of Slaves allowed to retransmit following the collision, by the first Master device using a collision resolution poll in accordance with a predetermined depth first tree search technique; and (3) retransmitting, by the subset of Slave devices, the information to the Master device, and, where another collision is obtained, recycling to step 2 and repeating steps 2 and 3 until all collisions are resolved.

System and method for hybrid contention/polling protocol collision

A method for providing access by secondary stations (12, 14, 16) to a shared transmission medium, maintains a list of secondary stations (12, 14, 16). A poll is transmitted poll by a primary station (10) to one of the secondary stations (12, 14, 16). The secondary station (12, 14, 16) waits for a poll, examines the transmission allocation, determines if there is congestion and transmits, along with the data in response to the poll, information regarding congestion. A system for providing such access includes a primary station (10) and a plurality of secondary stations (12, 14, 16). The primary station includes a polling controller (30), a receiver (32), a transmitter (34), a summer (36), a secondary station poll list database (38) and a data traffic controller (40).

Method and system for providing access by secondary stations to a shared

Automatically restoring data transmission by monitoring line degradation and switching to a new line (or lines) when line quality falls below a prescribed standard. Data transmission is maintained on the leased line while communication is being established on the dial line, so as not to disrupt data transmission; communication is established across two dial lines to restore full-duplex transmission; energy is maintained on the dial lines at times when data is not being transmitted to prevent a change of channel on a dial line; a signal processor, associated memory, and analog interface circuitry provide the data restoral functions; control of the restoral procedure is handled by one modem (e.g., the calling modem), and commands are sent to the other modem over either the leased or dial lines.

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Stoughton, MA, United States of America

Stephen Schroeder