Abstract: A gateway device couples a mobile telephone with a data network, such as the Internet, for voice communications. The gateway device is configured to provide a consistent interface with a user of the voice communications facility, independent of the method of user-access to the gateway device, and independent of the access to the data network. The gateway device allows for user-access from both wired and wireless telephone instruments, and provides the user a consistent service profile, independent of the location of the user at the time of access. The gateway device provides a service, such as a conventional “Voice over the Internet” (VoIP) application, that allows the user to place and receive telephone calls to other VoIP users, or to conventional telephone service users.

Abstract: A speech processing system receives multiple streams of speech frames. The system selects among concurrent ones of the frames a subset of those frames that are the most relevant, based on pre-assigned stream priorities and energy content of the frames. The selected frames are then decoded and rendered. The resulting signals are mixed. This architecture provides bandwidth scalability and/or processing power scalability.

Abstract: Compressed digitally encoded video signals are transmitted over an asynchronous transfer mode network with varying grades of service dependent on bitrate requirements for a desired picture quality and the currently available network capacity. To maximize transmission quality and minimize cost, the grade of service requested from the network is changeable in response to scene changes.

Abstract: A transmission system wherein a plurality of digital signals are coded and the coded signals are used to amplitude modulate respective carrier waves. The amplitude modulated coded signals are then combined for conveyance over a non-linear transmission medium. Due to the transmission non-linearity there will be distortion of the received combined signal, thereby reducing the transmission capacity of the system. In order to increase the transmission capacity, coding of the digital signals is carried out in accordance with a code such that the amplitude of the modulated carrier for digital symbols of higher probability is reduced in relation to the amplitude thereof for digital symbols of lower probability of occurrence.

Abstract: In a multiple access network a main station is to be capable of distinguishing signals transmitted by sub-stations to the main station. A method of realising this is the use of SCMA (SubCarder Multiple Access). According to this method the signal to be transmitted is modulated on a subcarrier having its own frequency and then modulated on a main carrier in each sub-station. In prior-art multiple access network the distribution signals which are to be transmitted to the sub-stations by the main station are modulated each on its own distribution subcarrier and then applied to a shared distribution modulator. For diminishing the requirements posed on the high-frequency properties of the electronic components necessary for the network, the subcarriers for distribution signals and return signals are selected to lie in the same frequency band.

Abstract: In a multiple access network the signals transmitted by a plurality of sub-stations to a main station over a common channel must be distinguished for each sub-station. A method of achieving this is to employ SCMA (Subcarrier Multiple Access), according to which in each sub-station the transmit signal is modulated on a subcarrier having a different frequency for each substation, and the modulated subcarrier amplitude modulates a main carrier which has substantially the same frequency for all sub-stations. To minimize mutual interference between sub-stations, according to the invention the amplitude of the main carrier transmitted by a sub-station is reduced during intervals in which the modulated auxiliary signal from that sub-station is not present or is at a zero reference level. In this way the number of modulated carrier signals which are present at any given time is reduced. Mutual interference is thereby significantly reduced, because it depends on the squared number of carriers present in the system.

Abstract: In a multiple access network, signals transmitted by a plurality of secondary stations to a primary station are to be distinguished by the primary station. One method for realizing this is by the use of Sub-Carrier Multiple Access (SCMA). According to the method of SCMA, a transmit signal is modulated on a subcarrier having its own frequency and then amplitude modulated on a main carrier in each secondary station. To reduce a mutual disturbance by the secondary stations in SCMA, according to the present invention, a transmit signal is converted into high-speed bursts of a transmit signal. As a result, fewer secondary stations on average are active, so that the mutual disturbance by the secondary stations will diminish.