Abstract: A digital broadcast receiver for determining the actual transmission mode of a Digital Audio Broadcast (DAB) signal with a delay circuit for delaying a received DAB signal is provided. With a correlation circuit for correlating a delay output of the delay circuit with the received DAB signal a moving average circuit for calculating a moving average of a correlation output of the correlation circuit. A transmission mode is assumed to be one of a plurality of transmission modes. The delay time of the delay circuit is set at a time corresponding to a symbol time length of the assumed transmission mode. The number of times that the output of the moving average circuit exceeds a prescribed value is counted. Based on counting results, the actual transmission mode is identified based on the maximum number of times that the output of the moving average circuit exceeds the prescribed value.

Abstract: A two-way communication system that can shorten the system recovery time when a link switching operation between a center station and a relay station occurs over two-way CATV networks, passive optical star networks and the like. A center station measures the round-trip propagation delay of a signal when a subscriber station starts its operation and then sets the transmission delay of the subscriber station so as to equalize the round-trip propagation delay to a fixed system delay. When a link switching operation occurs from a working system to a standby system, the center station measures the round-trip propagation delay of a signal for a subscriber station after the link switching operation and then resets transmission delays of all subscriber stations connected to the relay station to a time based on the difference between the measured delay and the round-trip propagation delay of a signal before the link switching operation.

Abstract: A method and system of determining a GGSN to serve data calls in a mobile communications network is provided. Messages are received from a SGSN, and analyzed to determine if the message is requesting the identity of a GGSN. If the received message is requesting the identity of a GGSN, a GGSN selection algorithm is executed to identify a GGSN to serve data calls from a specified MS. A reply is then constructed and sent to the SGSN identifying the selected GGSN.

Abstract: A method for flow control in asymmetric digital subscriber line (“ADSL”) devices. The method includes flow control that adapts to changes in line conditions such as noise signals, onhook/offhook signals, etc. that may result in degradations in the quality-of-service in an ADSL system. The flow control includes buffering outbound data and ceasing transmission of data at an original transmission rate on an ADSL device that is used on a customer site. An original data transmission rate is adjusted based on changes in line conditions. One more or data transmission characteristics may be adjusted before sending any data at a new data transmission rate. For example, Asynchronous Transport Mode (“ATM”) often uses ADSL devices as a physical layer to transmit data. ATM available bit-rate, constant bit-rate, variable bit-rate or unspecified bit-rate transmission characteristics or ATM quality-of -service characteristics may be adjusted before sending any data at a new data transmission rate.

Abstract: A packet network of interconnected nodes employs a constraint-based routing method to determine a path through the network for a requested label-switched path (LSP). Each of the nodes includes one or more routers that forward packets based on a forwarding table constructed from paths determined in accordance with the constraint-based routing method. The constraint-based method determines the path of the requested LSP based on the effect that routing those packets of the requested LSP may have on current and/or future demands on the capacity of network nodes for currently provisioned LSPs. Such constraint-based routing method may not necessarily route packets of a requested LSP along the shortest path, or minimum number of hops, through the network. Given the packet network and LSP request, a linear programming system is defined by a set of linear programming equations.

Abstract: There is provided a method and device for measuring a rate of message element traffic over a message path in a communications network. The path includes at least one connection and is associated with a maximum rate of transmission. The path is periodically polled for transmission of a message element, the polling being performed at a polling rate associated with polling intervals which are at least as frequent as the maximum rate of transmission. If transmission of a message element is detected during a polling interval, a running count of such detection is incremented, the running count of detection being associated with the connection over which the message element was detected. If transmission of a message element is not detected, a running count of such non-detection is incremented, the running count of non-detection being associated with inactivity of the message path.

Abstract: The current invention provides a method and apparatus for downconverting received digital data from the elevated frequencies at which the data is modulated. Various multi-tone communications systems (such as DMT in wire-line communication or OFDM in wireless communication) operate by up-converting output of the modulated signal at the output of the IFFT from baseband to a higher center frequency. Therefore, at the receiver, the inverse operation is required. At the receiver the signal must be down-converted to baseband before being available for processing by the FFT. In this invention, a simplified converter is provided, where the complex multiplication required by prior art downconverters is avoided, thus simplify the downconversion process and reducing power requirements. The apparatus and method may be implemented on a physical modem or a logical modem with the logical modem including a digital signal processor (DSP) coupled to an analog front end (AFE).

Abstract: A method and apparatus are disclosed for reclaiming frame buffers used to store data frames received by a network switch. The apparatus includes a multicopy queue for queuing entries corresponding to received data frames which must be transmitted by multiple output ports of the network switch, a free buffer queue for queuing frame pointers that identify locations in an external memory where reclaimed frame buffers are located, and a multicopy circuit that retrieves entries from the multicopy queue and determines if all copies of a received data frame have been transmitted by the specified output ports. The multicopy circuit also reclaims one or more frame buffers, based on the size of the received data frame. The present invention allows efficient reclaiming of frame buffers regardless of whether the received data frame is stored in a single frame buffer or multiple frame buffers.

Abstract: A controller module is coupled to a plurality of application modules over a backplane. The backplane comprises a differential bus(s) having a TX and RX data signal, a differential clock signal, and a single ended collision detection line. The application modules transmit data to the controller module. The controller module retransmits a recovered version of the data back to the application modules over the collision detection line. Each application module compares the retransmitted data bits with the data bits it originally transmitted. If the data is not the same, a collision has occurred and the application module removes itself from the bus. If the data is the same as that transmitted originally, that particular application module continues to transmit on the bus. Metastability at the controller module's differential receiver enables multiple differential transmitters to be on the differential bus at the same time.

Abstract: Despreading means 10 despreads a pilot signal included in a first received signal 1. Strength determination means 15 determines the strength of the despread pilot signal. Integration control means 16 determines the integration interval used by integration means 13, from the strength of the received pilot signal. The differences in strength detected by strength difference detection means 12 are added together by the integration means 13 over the period of time decided by the integration control means 16. The integration interval used by the integration means 13 is made changeable according to the receiving environment. Accordingly, when there is the superior receiving environment, there is reduced the load imposed on the integration means 13 when the integration means 13 performs the processing operations. Therefore, there can be realized a superior CDMA receiver phase tracking system which dissipates a fewer amount of electric power.

Abstract: The system and method of the invention enable any channel of a multi-channel communication link to be used for transmission of a control signal to a system component by a system controller. The system component, connected to the system controller by the multi-channel communication link, automatically locates the one or more signaling channels carrying the control signal(s) and then establishes communication with the system controller in accordance with the control signal(s). If no signaling channels are located after a predetermined number of attempts or after a predetermined period of time, the system component may, if particular conditions are met, reset itself before continuing to search for the signaling channel(s).

Abstract: An integrated multimedia encoding system is disclosed. Multimedia encoders which are capable of adjusting bit rates receive multimedia data to compress the data. After compressing the data, the multimedia encoders adjust the bit rates of the elementary streams responsive to a control input. Bit rates are increased or decreased using delays or, for video data, by allocating more or less bits to each macroblock, frame or group of frames. A unified memory module is coupled to the multimedia encoders to store the multimedia elementary stream data, the Program or Transport stream data, and data from other sources as needed. The unified memory is capable of adjusting storage allocations responsive to the realtime requirements of the incoming multimedia streams and the outgoing Program or Transport stream data.

Abstract: In an automatic gain control type demodulation apparatus, an orthogonal demodulation circuit receives an analog input signal to generate a first I-signal and a second Q-signal orthogonal to each other. An analog/digital converter circuit performs an analog/digital conversion operation upon the first I-signal and the first Q-signal to generate a second I-signal and a second Q-signal. An automatic gain control (AGC) circuit suppresses amplitude errors of the second I-signal and the second Q-signal to generate a third I-signal and a third Q-signal. A complex multiplier removes frequency and phase offset components of a carrier wave included in the third I-signal and the third Q-signal to generate a fourth I-signal and a fourth Q-signal. A phase detector detects first and second amplitude errors of the fourth I-signal and the fourth Q-signal, respectively, with respect to one normal signal point and calculates a phase error of the fourth I-signal and the fourth Q-signal.

Abstract: The invention relates to a data transmission method and a base station system. The method comprises transmitting radio interface information over a bidirectional data link between a base station and a base station controller. The radio interface information comprises signalling information, user information and error control information. The method is characterized in that the radio interface information is compressed to fit into at least one ATM cell by replacing the original error control information of the radio interface information with simple status information. Other information may also be compressed and inserted into the ATM cell. Realization of the method is exemplified in the DECT system. The invention also relates to the necessary means and their protocol stacks.

Abstract: A communication protocol stack apparatus and method determine the aggregate maximum header and trailer lengths(H, T) and a payload size(P) for each layer of the protocol stack and pre-allocate for each layer one or more buffers of a length equal to the sum of “H”, “T” and “P”. The layer copies receiving data into the pre-allocated buffer at a position determined by “H”, and copies its header and trailer immediately before and after the data in the buffer. The layer sets two references. The next lower layer copies its header and trailer into the buffer at the positions determined by the references and updates the references. The process is repeated until the lowest layer and data between the references is copied to a physical device for transmission.

Abstract: A multiplex communications system includes a plurality of master-slave sub-systems which include master nodes (10, 20) connected to a multiplex communications line (BL) and slave nodes (30, 40, 50) connected to the same. Each master node transmits a signal to the slave node of the same sub-system at a first given cycle, and in response the slave node transmits a signal, thereby establishing communication between the master node and the slave node. If periodic transmission of a signal at the first given cycle is not correctly carried out, the master node, which correctly performs periodic transmission of a signal, periodically transmits a signal to both the slave nodes at a second given cycle which is slightly longer than the first given cycle.

Abstract: An OFDM receiver system for performing precise OFDM demodulation is provided. The OFDM receiver system performs demodulation by sharing memories and operators in a time-divisional manner. FFT-processed data is separated into specific pilot signals and data according to the timing indicated by a controller to then be rearranged and stored, thereby facilitating extraction of corresponding pilot signals and data for various synchronization and equalization steps. Therefore, the demodulation system having an optimal structure can be realized in view of resource utilization efficiency and chip areas, the cost and time for fabricating and designing the system can be reduced, and verification of the system can be easily performed.

Abstract: A reliable facsimile transmission protocol and method for transmission of facsimile data over an IP network such as the Internet. The protocol features error correction through the use of a retransmission of packets with a flow-control window and a dynamic redundancy window which alters the number of redundant frames that are transmitted in the packet. The size of the dynamic redundancy window expands or contracts depending on the behavior and quality of the IP network, for example whether it exhibits choppy, error-causing characteristics.

Abstract: In a data communication network, a system clock rate can be inferred at a receiver by measuring the data rate during successive periods. This information is used to adjust or adapt a receiver output clock to the inferred system clock. To adapt a receiver buffer output clock frequency to the buffer input clock frequency, the level of the buffer is periodically monitored. If the fill level is greater than an upper threshold, the output clock frequency is incremented. If the fill level is less than a lower threshold, the output clock frequency is decremented. A count is maintained of the number of successive adjustment operations performed while the fill level is outside the range bounded by the thresholds. When the fill level returns to the bounded range, a number of reverse frequency adjustments are performed. The number of reverse frequency adjustments are less than the number of earlier opposite frequency adjustments, preferably by a factor of two.