Abstract: The present invention relates to packet-distributed data transmission of compressed data. According to the invention, parity bits are supplied to the compressed data. The parity bits are used in the entire transmission chain between an encoder having compressed the data, and a decoder which decompresses it. According to one embodiment, the data is speech and the packet-distributed network is a mobile radio network with packet-distribution in included links. However, sending in the radio link of the compressed speech is circuit switched.

Abstract: A method and system are provided for optimal routing of calls in an Internet Protocol-based Base Station System (IP-based BSS), whereby a plurality of new messages are introduced on the A-interface. One such message informs the BSS that the Circuit Identity Codes (CICs) included in the message can be connected to the BSS to provide optimal routing of one or more calls. Another such message informs the BSS that the CICs included in the message are to be restored as separate CICs on the A-interface. The provision of such messages overcomes the significant disadvantages of the existing and developing BSS implementations.

Abstract: A telecommunications system and method are disclosed for mapping a Transcoder/Rate Adaptor (TRAU) protocol onto a User Datagram Protocol (UDP) for use in an Internet Protocol (IP) based Base Station System (BSS) architecture. All in-band control bits in the TRAU protocol are not relevant when using the UDP protocol. Therefore, when speech information is mapped onto a UDP datagram for transfer to a Channel Codec Unit(CCU) in a Base Transceiver Station (BTS), some of the information normally transferred between a CCU and the TRAU can be removed. For example, a Time Alignment command included in some of frame types is not needed, and should be removed. In addition, bits relating to a frame structure, such as TRAU synchronization bits, tail bits and spare control bits, should be removed from all frame types. Furthermore, a new control bit that contains a sequence number must be added to handle reordering of a packet data stream.

Abstract: The present invention relates to a mobile communication system supporting communication of data which comprises a base station communicating with a switching arrangement. A communication protocol is used for communication between a mobile station and the switching arrangement. The connection between the base station and the switching arrangement supports packet switched communication and detecting means are provided in the base station to detect if data frames sent from the mobile station are correctly received over the air interface. Means are also provided for sending only data frames detected as correctly received onto the switching arrangement using the packet switched connection between the base station and the switching arrangement.

Abstract: A base station subsystem (BSS) and method is provided that handles an increase in traffic volume which temporarily overloads at least one terrestrial link in an IP network by gracefully downgrading the transmission rate of one or more calls. More specifically, the BSS includes a base station transmitter (BTS), an IP gateway and an IP network which passes at least one packet based call on a terrestrial link between the BTS and the IP gateway. The BTS and IP gateway each include an end-point having a buffer for measuring a delay in passing the at least one packet based call through the terrestrial link of the IP network and for downgrading a service when the delay as measured by one of the buffers exceeds a predetermined value.

Abstract: The present invention relates to an arrangement for improving the speech quality, especially for VoIP (Voice over IP) calls, which arrangement comprises a Transceiver and Rate Adapter Unit (TRAU) in which an encoded speech signal from a Mobile Station (MS) is transcoded, and for the purpose of reducing the necessary encoding/decoding for thereby avoiding detorioration of speech quality, and also for the purpose of avoiding reduction in bandwidth, it is according to the present invention suggested that said arrangement comprises means for either putting the TRAU in a transparent mode or letting the TRAU be bypassed altogether.

Abstract: A circuit emulation method with garbage removal is used to convert a circuit-switched network for packet-switched transmissions while reusing as much of the existing circuit-switched infrastructure as possible. The garbage removal function removes unnecessary information from a packet before it can be transported, which increases the transport efficiency and decreases the transport delay.

Abstract: A system and method reduces the delay of speech processing over a packet-switched network in a discontinuous transmission system. According to exemplary embodiments, a base transceiver station assigns priority indicators to information received therein. When the information is speech or a first SID frame, a high priority indicator is assigned. When the information is a SID update frame, a low priority indicator is assigned. The information is transferred from the base transceiver station to a base station controller in an order determined by the priority indicators. As such, the delay in transferring and processing speech information is reduced.

Abstract: A method and system are provided for optimal routing of calls in an Internet Protocol-based Base Station System (IP-based BSS), whereby a plurality of new messages are introduced on the A-interface. One such message informs the BSS that the Circuit Identity Codes (CICs) included in the message can be connected to the BSS to provide optimal routing of one or more calls. Another such message informs the BSS that the CICs included in the message are to be restored as separate CICs on the A-interface. The provision of such messages overcomes the significant disadvantages of the existing and developing BSS implementations.

Abstract: The present invention relates to a mobile communication system supporting communication of data which comprises a base station communicating with a switching arrangement. A communication protocol is used for communication between a mobile station and the switching arrangement. The connection between the base station and the switching arrangement supports packet switched communication and detecting means are provided in the base station to detect if data frames sent from the mobile station are correctly received over the air interface. Means are also provided for sending only data frames detected as correctly received on to the switching arrangement using the packet switched connection between the base station and the switching arrangement.

Abstract: A method for maintaining synchronization between a base transceiver station (BTS) and an interworking function (IWF) within a cellular communications network is disclosed. The method utilizes a synchronization procedure between the IWF and the BTS that makes the IWF aware of propagation delays between the IWF and BTS. The IWF utilizes this information to adapt to the delays such that the correct sequence is unpacked uplink when obtained from the base transceiver station. The IWF also uses synchronization data to control transmissions from the IWF to the BTS such that frame numbers and timeslots are received at the BTS in the correct sequence.

Abstract: The present invention relates to the technique of handover in mobile telephony. A new Transcoder and Rate Adaptation Unit (100 FIG. 3) is introduced which provides two uplink (230, 250 respectively, FIG. 3) and two downlink (240, 260 respectively, FIG. 3) channels. The use of these two channels (230, 250 respectively, FIG. 3) on the uplink during handover provides for the use of distributed handover on the uplink. The result minimizes the audible interruption during handover by minimizing the loss of Traffic Channel frames to what is possible within the GSM standard. Additionally, interruption of the speech or background noise during these lost frames is masked by an error concealment algorithm, since the Transcoder and Rate Adaptation Unit (100 FIG. 3) still has information from the Base Transceiver Station responsible for transmission before the handover.

Abstract: A system and method are provided for improving speech quality for signals divided into a frame structure. Speech information in a signal is detected, and a lost or corrupted transmitted frame is detected. The lost or corrupted frame is replaced by a suitable frame if a number of frames represented e.g., by a counter value, exceeds a predetermined value. The counter value may be changed, depending on whether the system is in a comfort noise generation state or in a muting period. The frame may be replaced by a frame representing mainly background noise, generated at the transmitting end during speech pauses or at the receiving end, or such a frame and a correctly received frame. The predetermined value may be the length of a muting period or may be the number of lost or corrupted frames preceding a speech frame. A first of the correctly received speech frames that follows a number of lost or corrupted frames may also be replaced. The output frames gradually approach pure speech frames.

Abstract: A method for protecting the transmission of network independent clocking and status information over an air interface between a mobile station and base transceiver station is disclosed. The method involves defining a parallel logical channel between the mobile station and base transceiver station to carry network independent clocking and status information. The network independent clocking and status information are removed from the data stream of the traffic channel and transmitted on the parallel channel over the air interface. Alternatively, a buffer may be used in conjunction with or singly to process the data stream of the traffic channel to delete or insert bits or characters to minimize or eliminate the need for network independent clocking information.

Abstract: A synchronization frame is first formatted and transmitted in accordance with the Global System for Mobile (GSM) 08.60 specification. After an initial synchronization procedure is accomplished between a transcoder/rate adaptor unit (TRAU) and a particular base transceiver station (BTS) serving a mobile station, a modified GSM 08.60 frame is thereafter used to transport greater user data payload across the established communications link. The modified frame replaces the synchronization bits included in the GSM 08.60 formatted data frame with user data to increase data payload from the conventional 13.5 Kbit/s to a more desirable 14.4 Kbit/s without altering the standardized 16 Kbit/s transmission rate supported by the IWF and the BTS.

Abstract: A method and apparatus for operating a first base station in a cellular telecommunications system, wherein the first base station has first and second transceivers that receive radio signals that are divided into uplink time slots, includes operating the first transceiver in synchronization with a first frame of uplink time slots and operating the second transceiver in synchronization with a second frame of uplink time slots, wherein the second frame of uplink time slots are offset by a predetermined amount relative to the first frame of uplink time slots. A united random access channel is formed by using a first time slot in each of the first and second transceivers in combination. A mobile station that transmits an uplink radio frequency burst may access the first base station by having the uplink radio frequency burst received by at least one of the first and second transceivers during that transceiver's first time slot.