Abstract: This invention discloses an image transmission method, which keeps the quality of the image transmission unchanged and increases the capacity for code division multiple access (CDMA) mobile communication system. By applying the subband coding with threshold method and differential perspective coding method, which change the image compression ratio and coding rate according to the characteristics of the image, the image transmission quality keeps unchanged. By changing the spread spectrum factor and adjusting the emission power accordingly or by applying the discontinuous emission mode without changing the spread spectrum factor, the purpose of increasing CDMA system capacity is reached.

Abstract: A method and apparatus encompasses a technique for routing an information packet through a satellite communications system 20 from a source satellite 38 to a destination satellite 40. A path through the system 20 is chosen for the packet and an identifier identifying the path is appended to the packet. In addition, an identifier identifying the destination satellite 40 is appended to the packet. Satellites in the system 20 then use the identifiers in the packet to route the packet to the destination satellite 40. If the chosen path is not available, an alternate path can be taken by the packet. In one embodiment of the present invention, a centralized controller 36 is provided for controlling the routing of packets throughout the entire system 20.

Abstract: A communication system that provides two-way digital communication between a central site and a plurality of user terminals via standard cable television networks and facilities free from interference from “carrier lock-on” and “ingress” by transmitting an FSK signal over one frequency channel from the central site to the user sites and transmitting two spaced FSK subcarrier signals, on two other frequency channels, from the user terminals to the central site, and where the receiver at the central site has two channels matched in frequency to the subcarrier frequencies and having a decoder that will not pass received information unless it has been received for a prescribed duration at a prescribed level.

Abstract: A sender converts a non-compressed packet, which is to be transmitted, into a full-header packet including a full header or a header-compressed packet including a compressed header, and sends the converted packet to a receiver. The receiver receives the packet transmitted from the sender, and converts the received packet into a decompressed packet. In cases the full-header packet or header-compressed packet is lost between the sender and receiver, the receiver keeps header-compressed packers received during an interval from the packet loss to the next earliest reception of a full-header packet, and decompresses the compressed headers of the kept header-compressed packets on the basis of contents of the full header of the full-header packet.

Abstract: The invention provides a power sharing amplifier system having an N by N transform matrix circuit, N amplifiers and an N by N inverse transform matrix circuit. The N by N transform matrix circuit has N input ports that respond to M input signals and provide N transform matrix input signals, where M is less than N. The N by N transform matrix circuit features at least one input port that does not receive an input signal but instead is coupled to ground. The N amplifiers respond to the transform matrix input signals and provide N amplified transform matrix input signals. The N by N inverse transform matrix circuit responds to the N amplified transform matrix input signals and provides N inverse transform matrix amplified output signals to output ports. Moreover, the N by N inverse transform matrix circuit features at least one output dissipation port that is coupled to ground to dissipate the intermodulation products contain thereon.

Abstract: A method and system are disclosed for measuring data traffic with parameters of the token bucket (with queue) traffic shaping model. Based upon measurements of data traffic, token bucket capacity is calculated as a function of token generation. The complexity of the calculations is linearly related to the number of data packets in the traffic pattern.

Abstract: A receiver for spread spectrum communication system receives a traffic channel and common control channel by a plurality of matched filters at least one of which is selectively available for the traffic or the common control channel. At the initial acquisition, a plurality of matched filters are used for receiving the common control channel. At the hand-over, a plurality of matched filters are used to receive traffic channels of the current base station and the base stations in the adjacent cells.

Abstract: A bridge that can effectively use plural paths by restricting a single path by a spanning tree algorithm, thus preventing that a broadcast packet is circulated in a looped communication path when two neighbor brides configuring a spanning tree are physically connected with plural paths. The bridge incorporates a correspondence table for the correspondence between the transmission source Mac address and the transmission destination port of a packet. A transmission source Mac address registration section decides the transmission destination port of a packet to be transmitted from the port to other bridge. The transmission destination port is cataloged on the table. When the transmission packet is a broadcast packet or BPDU packet, it is divided to a specific port among ports of the bridge. Other packets are divided to the corresponding ports by referring to the content cataloged on the table. Thus all the paths can be effectively used.

Abstract: To manage band allocation as a function of occupancy loading on a local network with high quality of service, the invention proposes a decentralized management protocol distributing allocation at all times by adapting the load of application streams to be transmitted to the bandwidths available on the network.

Abstract: The CDMA synchronous capture circuit which calculates correlation values by using a part of received data for the detection of the peak position, and then decides an upper temporal peak position where the correlation values are great. The CDMA synchronous capture circuit of the present invention calculates the remaining correlation values, giving priority over the temporal peak position, by using the remaining received data, and finally decides a peak value from the correlation level by adding the above-mentioned two kinds of correlation values.

Abstract: A data receiver for receiving data including multi-component signals representing symbols selected from a set of multi-component, multi-value symbols such as 16-QAM, 64-QAM or 256-QAM symbols. Each component of the signals denotes values for a plurality of bits, each bit being associated with one component of the signal. The receiver is arranged to set a value of a bit metric for each bit denoted by each signal based upon the value of the signal component associated with that bit. The bit metrics are selected so that when the signal component is in a first range, the bit metric is at a maximum; when the signal component is in a second range, the bit metric is at a minimum, whereas the signal component is in a third range, the bit metric has an intermediate value between the minimum and maximum values. The bit metric represents the probability that the receive signal represents a symbol denoting a particular value of the bit.

Abstract: The present invention includes interrogators, communication systems, communication methods, and methods of processing a communication signal. One aspect of the present invention provides a backscatter system interrogator including a downconverter configured to receive a backscatter communication signal having a first frequency and convert the backscatter communication signal having the first frequency to a subcarrier signal having a second frequency less than the first frequency; a filter coupled with the downconverter and configured to filter direct path energy from the subcarrier signal; and a gain control coupled with the filter and configured to adjust the gain of the filtered subcarrier signal.

Abstract: A message is encoded in a punctured convolutional code by an encoding process involving bit erasure and transmitted in a multi-component modulation system such as 16-QAM in which each component of a signal denotes values for more than one bit. At the receiver, a bit metric calculation circuit calculates a bit metric for each bit of data denoted by each received signal. The resulting sequences of bit metrics undergo bit insertion processing to yield one or more augmented sequences of bit metrics corresponding to the encoded message before bit erasure. The one or more augmented sequences of bit metrics are subjected to most-likelihood decoding scheme such as Viterbi decoding.

Abstract: A method and apparatus utilizing a data processing system are disclosed for multi-level data communication providing self-clocking. A first digital signal is input which includes a series of digital bits. One of a plurality of output levels is associated with each group of data bits for each of the plurality of the digital bits included within the first digital signal. A particular output level is associated with a clock output level. An output signal is generate which includes a transmission of the output level for each of the groups of digital bits and includes multiple transmissions of the clock output level, where a clock output level is transmitted after each transmission of an output level for each of the groups of digital bits.

Abstract: A system and method for user information transfer before modem connection. The invention makes high-speed modems more efficient, particularly for transaction and Internet applications, by providing for transmission of pre-connection user data during modem training. A training sequence for a modem in accordance with the invention may be summarized as follows: beginning training of the modem at a first data rate using a defined training sequence; after a selected amount of training, transmitting pre-connection user data from the modem at up to the first data rate while continuing training of the modem; ending training; and enabling transmission of user data at a full connected data rate of the modem.

Abstract: A communication system and method for transmitting relatively short data messages in the communication system. A dedicated frequency is sequentially switched into each of a plurality of satellite beams or traffic channels to transmit data messages at an increased power level to provide an increased signal margin. The increased power level of the dedicated frequency can be combined with coding and bit and message repetition to further increase the signal margin.

Abstract: The subject invention improves tracking performance of an adaptive equalizing operation while reducing the calculation volume. A frame including a training sequence and a mixed data sequence in which at least one symbol of a whitened sequence is dispersively inserted into a data sequence is generated. The frame is converted into a wireless signal, which is then transmitted. The wireless signal of the frame is received. Tap coefficients of an equalization filter are set by using the training sequence in the frame. During reception of the mixed data sequence, an adaptive operation is performed by using the respective symbols of the whitened sequence in the frame and the tap coefficients of the equalization filter are updated.

Abstract: A hybrid fiber/coax digital data transmission system in which data from a plurality of subscribers are transmitted upstream to a headend demodulator in a series of data bursts. The headend demodulator acquires and synchronizes a data burst by detecting a BPSK preamble having a repetitive one and zero pattern (10101010101000). The pattern is detected by integrating clock energy in an envelope of a preamble length transmission and using the last three symbols (0,0,0) as a frame marker after differential decoding. Noise in the system is periodically measured by detecting an empty burst placed periodically in the data stream. A first-in, first-out (FIFO) memory allows closer spacing for the data bursts by permitting asynchronous received and output clocks.

Abstract: A system and method for transparently transmitting aural signals across a wide area network (WAN). The system of present invention is connected to one or more of a private branch exchange, a key telephone system, a telephone, a facsimile machine, and a modem, for example. In the case of voice transmission, a user places a telephone call using the same procedure that is used when placing a telephone call over a conventional public switched network. The aural signals are translated into a format that is compatible with the local area network (LAN) and the translated signals are transmitted to a router or a switch that connects the LAN to the WAN. The data is transmitted across the WAN to a router or switch coupled to a second LAN. The data is then sent to a destination central site unit or PC which translates the signal into a format that is compatible with the telephone system connected thereto.

Abstract: A method and system are provided for communicating in a time-varying medium. A transmitter sends transmissions of the same message data separated in time with respect to one another. A single sensor receives the transmissions. Each received transmission is buffered until all of the transmissions that were sent are received. The buffered transmissions are simultaneously processed via multichannel adaptive equalization only when all of the transmissions that were sent are received.