Abstract: A mobile communication system transmitting data in frame unit includes a base station apparatus and a terminal apparatus. The transmitter has a controller having consecutive first and second frames each divided into a first interval and a second interval following the first interval. In a handoff mode, the controller transmits respective frame data in the first interval of the first frame and the second interval of the second frame and stops transmission of the data in the second interval of the first frame and the first interval of the second frame. Further, the terminal apparatus (i.e.

Abstract: A method and a system for expanding the capacity for transmission of information in a data frame which comprises at least an information element and a control element. After the data frame is subjected to channel coding, a portion of the control element is either removed or replaced by a divided portion of the information to be transmitted in the data frame.

Abstract: An information transfer system includes circuit packages each being connected in cascade through a transmission line. An input cell stream including idle cells is transferred through the transmission line from an input circuit package to an output circuit package. The idle cells of the cell stream are used to transfer necessary control information to the circuit packages through the transmission line. In the input circuit package, a control cell is generated which includes a plurality of control signals each including the control information and specifying information. The control information set is inserted into an idle cell detected from the input cell stream to produce a multiplex cell stream. Each circuit package is provided with an information detector which detects its own control information from the multiplex cell stream based on the specifying information.

Abstract: A data transfer rate control method inserts a stuff packet in real time to resolve the problem present in an ATM transmission for MPEG data. The method, for controlling a data transfer rate at which coded data are transferred in an asynchronous transfer mode may include the steps of: forming the coded data for an AAL layer (ATM Adaptation Layer); calculating an insertion timing for insertion of a NULL packet; inserting the NULL packet into the coded data of the AAL layer in consonance with the insertion timing, obtained by the calculation, for the NULL packet; and transferring, in the asynchronous transfer mode, the coded data of the AAL layer into which the NULL packet is inserted.

Abstract: A timing technique for a Quantization-Level-Sampling (QLS) modem puts timing information in a downstream pulsed signal transmitted from the public switched telephone network (PSTN) to the QLS modem. In response to this timing information, the QLS modem synchronizes to the network sampling clock in the PSTN. In particular, the pulsed signal includes data-bearing samples, which were provided by a far-end QLS modem, and at least one non-user-data-bearing (NUDB) sample in which the level of this NUDB sample periodically alternates. The QLS modem extracts timing information from this periodic alternating signal level to synchronize the QLS modem to the network sampling clock.

Abstract: Data are transmitted in blocks over a channel together with control signals for coordinating access to the channel. The control signals have the same values as some of the data blocks, these values being selected so that the control signals are spaced throughout the population of data block values and so that there is a greater Hamming distance between the control signal values than between the data signals. The control signals are transmitted between delimiter signals which differ from any of the data block signals, and are passed through a scrambling and encoding system in the same way as data signals, so that the spectrum of radiated electromagnetic emissions from the channel is not affected by the control signals.

Abstract: A method for selectively modifying an information signal at a remote site in a telecommunications system having a head end and a number of remote sites connected to form a ring. An initiation signal is received at a head end. The initiation signal indicates when to start modifying the information signal. Further, the method retrieves at least one stored modification signal. The method also transmits the modification signal to at least one selected remote site over a packet ring network of the telecommunications system. The packet ring network includes ring switches that self-learn the location of network devices based on addresses in packets processed by the switches and which learn that addresses of network devices associated with other ring switches are reachable out of at least one ring port of the ring switch. The information signal is modified with the modification signal. The method also detects the end of the modification signal and ends the modifying of the information signal.

Abstract: A method and system for transmitting control information, such as Fast Associated Control Channel (FACCH) information in a digital TDMA communication system. Control information, when required, is transmitted over every other TDMA frame, and speech and data are transmitted over the remaining TDMA frames. Coding protection is reduced during transmission of the control information.

Abstract: A method for diminishing the effect of transmission errors in samples produced on the output of a decoder in a data transmission system, wherein the samples are attenuated when transmission errors are detected during various successive frames. The invention makes it possible to take isolated transmission errors into account when they are situated in a silence, that is, when they are particularly annoying to the user.

Abstract: A method for selectively enabling one of X agents in a system so as to allow the selected agent to be active in a shared communication system. The method comprises the steps of assigning each agent to a unique subset M of a plurality of N select lines, M being greater than 1 and less than N, and translating an identification number so as to assert M of the plurality of N select lines. The asserted M select lines uniquely select a designated agent. For one embodiment, all of the X agents may be selected by enabling all N select lines. For another embodiment, more than one but not all of the agents may be selected.

Abstract: The disclosure concerns a procedure for insertion of samples representing digital data from a first source having a first bit rate in a digitized signal from a second source having a second bit rate, wherein the second bit rate is greater than the first bit rate, and each data of the first source is associated with at least one sample of a series of samples at the second bit rate, the samples being presented to a polyphase filter for which a set of coefficients is associated with a specific phase error previously introduced by said associations, the filtered samples being included in the digitized signal. The invention also includes a device that implements the above insertion procedure. The invention is applicable notably in the field of insertion of Teletext data into a digitized video signal.

Abstract: Variable length LAN frames can be segmented into fixed length cells to allow the data in the frames to be transported through an intermediate cell-based system, such as an ATM network. Where transport through the intermediate system results in time gaps between data units extracted from the cells, special symbol combinations can be inserted into the time gaps to permit frame-representing data to be forwarded toward its destination as a "stretched frame" without waiting for all the cells representing the frame to arrive. When a stretched LAN frame is received at a "stretch-aware" LAN station, the special symbol combinations are detected and removed to recover at least the data payload of the original LAN frame.

Abstract: A radio telephone apparatus for performing space diversity reception to communicate with base stations in a TDMA radio communication system under an operating condition in which a frame period containing a signal transmission period, a signal reception period and a base station observation period is provided, which comprises first and second antennas for signal transmission in the signal transmission period, the space diversity reception prior to each of the signal reception period and the base station observation period and signal reception in each of the signal reception period and the base station observation period, and an antenna selector operative to select one of the first and second antennas in accordance with space diversity technique to be used for receiving a data signal from a specific base station in the signal reception period and to select further one of the first and second antennas in accordance with space diversity technique to be used for receiving a data signal from one of base stations ot

Abstract: A data transmission system is used for the transmission of a large number of telephone channels between nodes in a transmission network built as a Synchronous Digital Hierarchy (SDH), where a pulse frame (e.g. STM-1) contains a large number of bytes, each of which can be used for the transmission of a telephone channel or of overhead signals for the administration of the system, and where signals from a Plesiochronous Digital Hierarchy (PDH) are introduced into the pulse frame of the Synchronous Digital Hierarchy, so that the signals from the Plesiochronous Digital Hierarchy when introduced do not occupy all the bytes in said pulse frame. At least some of the bytes of the pulse frame which are not occupied by introduction, are used for the transmission of user-specified data signals.

Abstract: A master station and at least one slave station are connected by radio channels. Each slave station transmits data to the master station by time division multiple access. A first circuit equally divides a prescribed area into at least two sub-areas. The prescribed are is defined in a burst signal for transmitting data from each slave station to the master station, the prescribed area being provided for an arrangement of message signals which are sent from at least one terminal connected to the slave station. The first circuit also arranges a message signal in each sub-area. A second circuit generates a burst signal in which at least a control signal and a channel quality monitoring signal are arranged. The control signal and the channel quality monitoring signal are generated in the area peripheral to each sub-area in which a message signal is arranged. The prescribed area in the burst signal may be an area corresponding to a data quantity of 64 kbps in transmission speed.

Abstract: A method and an apparatus for removing the silence from the digitalized voice signals conveyed through packets or cells switching networks. The silence samples are neither packetized nor sent over the network but are regenerated at the output of the network. The silence samples generated are white noise samples, where the level is adapted to the background noise of the silence samples received at the input node of the network. For long periods of silence, the white noise level is periodically refreshed to be adapted to the last silence samples received at the input node of the network. The method provides also a control of packet or cell loss. The method uses are not control packets; in the later case, it can be used for ATM networks with AAL1. The method is implemented as a program executed in a Digital Signal Processor located on adapter cards dedicated to voice processing in the network access nodes.

Abstract: In a mobile satellite communication system including a land-earth station which communicates with a mobile earth station via a satellite, a method is employed for providing an overlay short messaging service. According to the method, a short messaging service is selected. In addition, a short message is transmitted from one of the land earth station and the mobile earth station via the satellite to the other. The short message is transmitted in one of a plurality of out-of-band signalling channels. The transmission occurs at a time when no signalling information is being transmitted.

Abstract: By constructing a plurality of packs from a first packet including first data having a high bit rate and a second packet including second data having a low bit rate, when the first data and the second data are multiplexed, it is first detected whether a data length of second data is smaller than a maximum data length of second packet or not. Subsequently, when it is detected that the data length of second data is smaller than the maximum data length of second packet, one pack is constructed by a redundancy data packet including redundancy data of a data length which is equal to a difference between the maximum data length of second packet and the data length of second data and the second packet.

Abstract: In the case of an OAM cell for each of N paths being generated and transmitted at a rate of one OAM cell per a predetermined time period of 1 second in each of the N paths, first, N subperiods is prepared which are allocated to the N paths, respectively, and are obtained by dividing the predetermined time period by N. From the N subperiods, a single subperiod is sequentially selected. A cell stream is checked for an idle cell and the OAM cell for a single path of the N paths corresponding to the single subperiod selected is checked whether it is requested to be inserted into the cell stream within the single superiod selected. When an idle information block is first detected and the OAM cell is requested to be inserted into the cell stream, the OAM cell is inserted into the first idle cell which is first detected within the single subperiod selected.

Abstract: An audio-on-demand communication system provides real-time playback of audio data transferred via telephone lines or other communication links. One or more audio servers include memory banks which store compressed audio data. At the request of a user at a subscriber PC, an audio server transmits the compressed audio data over the communication link to the subscriber PC. The subscriber PC receives and decompresses the transmitted audio data in less than real-time using only the processing power of the CPU within the subscriber PC., According to one aspect of the present invention, high quality audio data compressed according to lossless compression techniques is transmitted together with normal quality audio data. According to another aspect of the present invention, metadata, or extra data, such as text, captions, still images, etc., is transmitted with audio data and is simultaneously displayed with corresponding audio data.

Abstract: The present invention generates a reference signal including identification information based on a first coding method and generates data signals by a second coding method different from the first coding method. Next, it time division multiplexes signals by allocating the reference signal to a reference time slot and allocating data signals to time slots of which phase difference between the reference time slot is predetermined, and sends a multiplexed signal. In a receiver side, the reference time slot is detected based on identification information in a transmitted signal.

Abstract: In a packet network, message packets (130) are comprised of vacant or unused bits for future system enhancements or for remedying unknown design oversights or utilizing vacant portions of fixed length data packets. Furthermore, message packets (130) comprise a message type identifier distinguishing message architecture. A transmit and receive packet network node (100) maintains an unused bit catalog (125) listing vacant or unused bits of particular message packet types. When a message packet type having vacant or unused bits is detected propagating through the packet network, background data is retrieved from a transmit background data queue (115) and interleaved into such message packets to form enriched message packets (130') for transportation through the packet network. Receiving packet network nodes (100) detect enriched message packets (130') and extract and buffer the background data.

Abstract: A speech freeze-out method in a communication system for transmitting speech information, which is sent from public telephone terminals (1) to a control center (5) through voice channels, from the control center (5) to a base station (8) through time division multiplexing radio frequency channels (6), and from the base station (8) to mobile stations (17) through transponders (13). The freeze-out processing is carried out when the control center (5) feeds the speech information to the time division multiplexing radio frequency channels (6) so that the number of transmission channels from the base station (8) to the transponders (13) is limited within an upper limit value.

Abstract: A radio apparatus according to a TDMA/TDD system uses its own transmitter and receiver so as to perform a loopback test for checking normality of the apparatus during a period of an unassigned slot. A loopback test signal is output from its own transmitter during an unassigned transmitting slot and is received by its own receiver. The signal is temporarily stored in a memory and is read during an unassigned receiving slot. The apparatus thus performs a loopback test. Since a loopback test can be performed by use of its own transmitter and receiver during an unassigned slot, a transmitting and receiving device (tester) specifically used for a loopback test is not required. Also, a loopback test can be carried out even while normal communications are being made.

Abstract: Data signals such as a pseudo noise pattern and character data are transmitted along with voice signals over one voice signal channel, thereby allowing an accurate measurement of communication channel quality during communication or enabling concurrent transmission of both voice and character information over one communication channel. At the transmitting end, a silence interval is detected by a voice detector, and a selector is controlled so that a PN pattern, with a start signal and an end signal appended at the start and end thereof, is substituted in the silence interval. At the receiving end, the start signal and end signal are detected by a silence notification frame detector, and a selector is controlled so that background noise is substituted in the intervening period.

Abstract: Low-frequency interference components produced by a time division multiple access (TDMA) portable radio transmitter that might potentially interfere with devices sensitive to low frequencies, such as cardiac pacemakers, are substantially produced. In those TDMA frames in which a protocol calls for either a burst of an information-bearing signal to not be transmitted in its designated time slot, or transmitted at a reduced power level, or for a shorter duration, an interference-compensating signal at a compensation frequency other than the transmitter's carrier frequency is transmitted. The interference-compensating signal is transmitted in the time slot in which the transmitter normally transmits the burst at a power level equal to the power level of the burst. If the protocol calls for a reduced power burst, the interference-compensating signal is transmitted within an adjacent time slot at a power level that compensates for the reduced burst power level.

Abstract: A communication device (e.g., 106) having multiple transmission modes employs a method of transmitting user information (309, 310) and intermittent overhead data (307, 308). The communication device (106) selects from a first transmission technique and a second transmission technique. When the first transmission technique is selected and overhead data (307) is to be transmitted, the communication device (106) replaces a first predetermined amount of the user information (309) with the overhead data (307) to form a data unit. When the second transmission technique is selected and overhead data (308) is to be transmitted, the communication device (106) replaces a second predetermined amount of the user information (310) with the overhead data (308) to form the data unit, wherein the second predetermined amount is less than the first predetermined amount.

Abstract: Improved throughput is provided in a spacecraft TDMA cellular communications system by in-call signalling without the need for flag bits, while still allowing the in-call signaling to be differentiated from other traffic. The terrestrial locations include mobile user terminals and gateways which provide connections to the land telephone line system. The spacecraft includes a transmitter and receiver, and an antenna which forms a plurality of spot beam footprints, in which the terrestrial terminals are located. Each of the terrestrial terminals transmits signals to, and receives signals from, the spacecraft. Each of the terrestrial terminals includes an encoder/decoder, for encoding at least call maintenance control signals, for temporarily interrupting the traffic signals to allow another action. The control signals may have bit content which exceeds the bit-carrying capability of the TDMA bursts, so transmission of the control signals must extended over a plurality of bursts.

Abstract: A digital communication network has a first end office which includes a first multiplexer unit and a second end office which includes a second multiplexer unit. The network performs transmission and reception of multiplexed signals between the first end office and the second end office. A monitor unit is provided within the first end office. Monitoring is performed of the accuracy of the signal received by the second end office from the first end office, signal accuracy information with regard to the received signal being included as subsignalling information in the input signal Sin which is input to the first end office from the second end office. The subsignalling information is extracted by the monitor unit from the input signal, so as to enable monitoring of the signal accuracy of the input signal. The result is a significant improvement in the improvement of transmission quality monitoring service provided in the digital communication network.

Abstract: The invention relates to a method for the transfer of data transmitted from a base station (PBS) to a central station (PAC) in a personal paging network, comprising base stations (PBS) for transmitting paging messages over a radio and a central station (PAC) for controlling operation of the base stations on the basis of data received from the base stations. The radio channel used for the transmission of paging messages is also used for the transfer of said data to be transmitted from the base stations (PBS) to the central station (PAC).

Abstract: A communication system includes a master station connected to a telephone line network and a plurality of remote stations for transmitting and receiving digital data to and from the master station through a radio transmission line. Among the master station and the remote stations, one channel is divided into a plurality of slots. One of the plurality of slots is assigned as a control slot to transmit and receive data in a time-division manner. The master station transmits control data to the remote stations by the control slot. The master station transmits control data by the control slot at every predetermined period and also transmits data concerning a communication by the control slot during a predetermined period.

Abstract: An ATM cell switching apparatus which prevents degradation of user cells in the ATM switch and preserve the quality of control cells, even upon increase in the control cells. Control cell discriminator 2.sub.1 discriminates whether the cells on the input cell highways 1.sub.1 are control cells or user cells, and output control cell dropping instruction signal 3.sub.1 when the cells are discriminated as control cells. Control cell dropper 4.sub.1 distributes the user cells onto the cell highways 5.sub.1 and the control cells onto the input control cell highway 6.sub.1. Control cell processing unit 8 performs a termination of the control cells and processes necessary operation ralating to the control cells. The control cells to be output are temporarily stored in the control cell FIFO 13.sub.1, and inserted into an idle cell position in the switch output cell highway 10.sub.1 when an idle cell is appeared. If no idle cell is available, the idle cell output instruction signal 14.sub.

Abstract: An apparatus and method, applicable to variable bit rate video and constant bit rate video, is disclosed for replacing "stuffing bytes" with private data. The invention takes advantage of the otherwise wasted resources dedicated to "stuffing" in a data stream in order to insert private data. This is accomplished by inserting useful private data in a Transport Stream instead of the stuffing bits. That is, effectively, a re-multiplexing operation occurs where, based on the existence of certain conditions in a Transport Packet (e.g., stuffing bytes exist), the information necessary to replace stuffing bytes with private data yet still comply with established standards is accomplished. This data generally is referred to as privatestuff data in order to distinguish it from typical private data which may otherwise be encoded into a Transport Stream. The stuffing bytes removed from the Transport Packet may come from an adaptation field in the Transport Header or directly from the Transport Payload or both.

Abstract: A recording/reproducing apparatus for a data packet stream having an extractor for extracting data packets of a selected type from an input packet train in which different types of data packets have been time-division multiplexed together. The apparatus also has a recording circuit for recording the extracted data packets, and a reproducing circuit for reproducing the recorded extracted data packets. A dummy packet producer, which produces dummy packets that correspond to data packets that have not been extracted, is also provided. Further, the apparatus has an output circuit that outputs an output data packet train. The output data packet train is produced by combining the reproduced extracted data packets and the dummy packets in accordance with the order in which the different types of data packets are positioned within the input packet train.

Abstract: At a transmitting end, frequencies used to a construct a digital signal are substantially removed from an analog signal by a notch filter circuit to produce an interim signal which is then combined with the digital signal as by combining to produce a composite analog signal that is transmitted to a receiving end. At the receiving end the frequencies used to construct the digital signal are substantially removed from the composite analog signal by a notch filter circuit. In this way the digital signal can be transmitted simultaneously with the analog signal without errors that could be introduced by the analog signal, and with only a slight change to the frequency spectrum of the analog signal. In a second embodiment, the system provides clear and error free continuous transmission of digital signals over an analog channel simultaneously with an analog signal by periodically analyzing the analog signal and, during any given period, transmitting the digital signals in open bands, i.e.

Abstract: A variety of methods of coordinating communications between a plurality of remote units and a central unit to facilitate communications using a frame based discrete multi-tone (DMT) transmission scheme am disclosed. In one aspect of the invention, synchronized quiet times are periodically provided in the upstream communication stream. The synchronized quiet times are used to handle a variety of control type functions such as synchronization of new remote units, transmission channel quality checking and handling data transfer requests. The information received is used to facilitate the dynamic allocation of bandwidth during use. In another aspect, a data request signal may be used to indicate either a desire to transmit at a particular data rate or a desire to transmit a particular amount of information. In the former case, the central unit allocates sufficient sub-channels to the remote unit to facilitate transmission at a requested data rate that is specified in the data request information.

Abstract: Data capacity mismatches between a communication node, including end node work stations, and a communication link usually require large buffer storage to prevent the loss of transmitted data frames due to transmission of an incomplete frame. Transmitted data frame continuity is maintained in the present invention by using small FIFO buffers in the node to store small portions of a data frame as data is sent and received. In addition, the data frame is maintained by stretching the transmitted frame on the link when necessary to prevent loss of the frame and compress the stretched frame when it is received from the link. The stretching and compressing is accomplished by inserting and removing non-data symbols, or command code words, in the transmitted and received string of data words. Small FIFO buffers (much less than a data frame in data capacity) operate on the fly to transmit and receive data without requiring contiguous transmission of a complete frame.

Abstract: An arrangement for modulating orthogonal signals with an analog signal or a digital information signal. In either event, the information signal is partitioned into component signals which respectively modulate an associated one of the orthogonal signals. The analog signal has a predetermined bandwidth and may be represented by samples generated at no less than a predetermined rate. The component signals derived from this analog signal, on the other hand, may be represented by samples generated at a rate which is less than the predetermined rate. Apparatus is incorporated which detects a predetermined event which, in turn, determines whether the orthogonal signals are modulated by the analog or digital information signal. The value of the latter signal may be known at any time, such as when the digital information signal is a training sequence, or may be unknown. The foregoing modulation arrangement can also incorporate privacy or encryption schemes.

Abstract: A high-speed signal input to and output from a high-speed optical interface part connected to an optical fiber transmission line is switched to different lines such that the switching is conducted by cross connect parts on an arbitrary basis. The high-speed signal is separated so as to obtain the low-speed signal. The low-speed signal output from the cross connect parts is separated so as to obtain the subscriber signal by signal terminal parts. Call connections are conducted for each subscriber by a time slot interchange part, whereupon a subscriber interface part performs analog-to-digital and digital-to-analog conversion so as to serve as an interface for a subscriber.

Abstract: A mobile radio for operation in a system includes a plurality of mobile radios, in which each mobile radio transmits, selectively, traffic frames containing traffic data responsive to inputting of information to the mobile radio when the mobile radio is in an active transmit state of operation, and silence descriptor frames responsive to absence of input information when the mobile radio is in active transmit state of operation. The mobile radio includes: a transmitter for transmitting traffic on a radio channel; a receiver for monitoring signals on the radio channel; a control input for inputting a transmit command; a controller, responsive to the receiver and responsive to the control input, for controlling the transmitter, where the controller is arranged to enable activation of the transmitter, when the receiver detects continuous silence descriptor frames on the radio channel for a predetermined duration and a transmit channel command is input at the control input.

Abstract: A paging network having a master transmitter and several local radio transmitters is disclosed. The network is designed to allow the transmission of local and global messages. Global messages must be sent by all radio transmitters synchronously. Local messages are only sent by a single radio transmitter. The master transmitter generates a signal that contains the global messages and sends it to the radio transmitters. If a radio transmitter has no local messages to be sent, it emits the unchanged signal received from the master transmitter. If a radio transmitter has one or more local messages to be added to the signal, it will determine if there are suitable gaps in the signal received from the master transmitter where the local messages can be included. If such gaps are found, the local messages are added to the signal to generate a modified signal which is then emitted by the radio transmitter.

Abstract: A video data transmitter includes: chrominance-data multiplexer which multiplexes parallel data obtained by digitizing a chrominance signal Pb, which is a component signal of an analog HDTV video signal, with parallel data obtained by digitizing a chrominance signal Pr; a word multiplexer which multiplexes parallel data obtained by digitizing a luminance signal Y, which is a component signal of analog HDTV video signal, with the output data of the chrominance-data multiplexer, and a parallel-to-serial converter which converts the parallel data output from the word multiplexer. A video data receiver includes a serial-to-parallel converter which converts received serial data into parallel data and a word separator which separates the output data of the serial-to-parallel converter into parallel data in the Y channel and parallel data in the Pb/Pr channel.

Abstract: A method used in a communication system (10) having central controllers (14) in communication with a plurality of user devices (12) where synchronizing data (34) and user data (35) are transmitted for a predetermined period of time defining a dwell (30). The method for delivering data to more than one user device (12) simultaneously includes the steps of providing an indicator (34) associated with at least a portion of a dwell indicating that the transmission of user data (35) is directed towards more than one user device (12), and informing the user devices of the repetition rate at which the indicator is transmitted. The user device schedules periods of time during which it is enabled and disabled respectively, based upon the repetition rate of the indicator received such that the user device is enabled and receives the data directed towards more than one user device.

Abstract: A slip buffer includes a first-in-first-out memory, an input address generating means, an output address generating means, and a slip buffer control logic. The input address generating means generates addresses into which data is read into the first-in-first-out memory. The output address generating means generates addresses from which data is read from the first-in-first-out memory. The slip buffer control logic includes a first latch, a second latch and a slip address generation means. A first boundary address of a first frame boundary is stored in the first latch. The first latch includes a first validity bit which indicates whether the first boundary address is valid, A second boundary address of a second frame boundary is stored in the second latch. The second latch includes a second validity bit which indicates whether the second boundary address is valid.