Abstract:
In accordance with a first aspect of the present invention there is provided a telephone apparatus including a transmitter portion and a receiver portion, an input transducer for converting input audio signals into electrical signals, a connectable input link between the input transducer and the transmitter portion to deliver whenconnected an input electrical signal to the transmitter portion to be transmitted by the transmitter portion, an output transducer for converting an output electrical signal into an audio signal and a connectable output link between the receiver portion and the output transducer for delivering when connected an output signal to the output transducer, optionally an echo cancellation circuitry portion adapted to sample the output signal and produce an echo replica signal, optionally a mixer included in the input link for mixing an echo replica signal produced by the echo cancellation circuit with an input signal produced by the input transducer, and an echo suppression circuitry portion including detector means for producing a first magnitude signal which represents a magnitude property of a first smple of an output signal S o in the output link and a second magnitude signal which represents a magnitude property of a second sample of an input electrical signal S i in the input link between the mixer and the transmitter portion, an analyser, connected to receive inputs comprising the first and second magnitude signals from the detector means, for measuring a relationship between thefirst and second magnitude signals and for producing a control signal when the relationship exceeds a threshold, wherein the detector means is operable periodically to analyse characteristics of the signal S o to estimate the amount of background noise in the signal S o and to pass as an input to the analyser a signal representing the estimated amount of backgroudn noise wherein the threshold above which the analyser produces an output control signal is set adaptively by the analyser dependent on the estimated background noise.
Abstract:
A method and system for operational improvements in a dispatch console in a multi-source environment includes receiving (310) a plurality of audio streams simultaneously from a plurality of mobile devices, transcribing received audio streams by the means of speech-to-text conversion, presenting real-time transcriptions to the user and determining (320) if a first keyword is present in at least one of the plurality of audio and/or text streams. Upon determining the presence of the first keyword, the dispatch console automatically performs (330) at least one predefined dispatch console operation from a list of predefined dispatch console operations. The dispatch console further receives (340) a second keyword based on determining the presence of the first keyword and checks (350) for the presence of the second keyword within the audio and/or text streams thereby enabling additional automated dispatch console operations.
Abstract:
A method of reducing impact of interference on a first control channel in a digital wireless communication system comprising a backup control channel, wherein the first control channel is being replicated (104) into plurality of control channels and a wireless communication unit operating on the first control channel switches (118) to one of the replicated control channels.
Abstract:
A method for use in a mobile communication system for estimating the location of a target mobile station (MS) which includes receiving signals from the trarget MS at a plurality of receivers in differencet locations and calculating the location of the target MS from information obtained from the received signals, wherein the calculation of location is carried out by the searching MS. The method may involve the target MS and the searching MS or MSs communicating by a direct mode of operation (DMO) link. The searching MSs may conveniently have GPS attachments. A mobile station which may be used as the target MS or as a searching MS and a system incorporating the same is also disclosed.
Abstract:
A cell-based communication system (10,58) having at least two cells (60,62) facilitating a communication link between at least one of a plurality of mobile stations (88-92) and at least one of a plurality of base transceiver stations (74-86) is characterised by at least one mobile station (88) and/or its respective serving base transceiver station (74) having means (94, 96, 108) for providing cell parameter information of a neighbour cell (62) which information is known to both the mobile station and its serving base transceiver station so as to facilitate handover of a communication between the respective serving base transceiver station (74) and a second base transceiver station (76) serving the neighbouring cell (62) without the mobile station accessing or receiving information from the neighbouring cell providing said neighbouring cell parameter information. A radio transceiver unit, base station transceiver and method for use in the system are also described.
Abstract:
At least one subscriber unit (SU) (110) can register with a radio frequency (RF) site (120) for radio services. For each registered SU, a SU push to talk over cellular (PoC) client (342-346) can be activated/established. Communications can be mapped at the RF Site (120) between each registered SU (110) and a corresponding SU PoC client (342-346). Each SU PoC client (342-346) at the RF site (120) can be communicatively linked to a remotely located PoC server (132) using a PoC interface (226). The SU PoC client (342-346) is a communication endpoint of the PoC server (132). In one embodiment, a talkgroup PoC client (350-352) can be established at the RF site (120) that is linked to the PoC server (132). Radio communications to and from the SU (110) can be routed through the SU PoC client (342-346) and/or the talkgroup PoC client (350-352) and through the PoC server (132).
Abstract:
Echo canceling method including the steps of determining an Euclidean norm of an echo-replica signal, determining an Euclidean norm of an input signal, determining a gradient step size, correcting the coefficients of an adaptive filter, deriving an updated echo-replica signal, and determining an updated error signal by subtracting the updated echo-replica signal from the input signal.
Abstract:
A method for sharing access to a resource in a mobile communication system by a plurality of mobile stations in the system, comprises the steps of: (a) assigning mobile stations to one of a plurality of location classes depending on the location of the terminal relative to a fixed terminal of the system; and (b) providing the mobile stations in each location class with random access opportunities to access the resource, the random access opportunities being different for the different location classes; and characterised by the steps of: (e) monitoring the number of random access attempts being made in a given period of time by mobile stations in the different location classes; and (d) dynamically adjusting the ratio of random access opportunities available to mobile stations in the different location classes using the monitored numbers. Also disclosed are a system, system infrastructure apparatus and mobile stations which operate using the method.
Abstract:
A wireless communication system (100) includes at least one wireless serving communication unit (122) having a processor (320), operably coupled to a transmitter (220), encrypting network identification data (330) for transmission to a remote communication unit (112). A remote communication unit (112) includes a receiver (210) for receiving encrypted network identification data (330) from at least one of the serving wireless communication units (122-132), and a processor (360) to decrypt the encrypted network identification data (340) in order to determine whether the serving wireless communication unit (122) is a valid serving wireless communication unit (122). A remote communication unit (112), a broadcast message, a wireless serving communication unit (122) and method for obtaining network identification data (330) 20 are also provided. In this manner, fraudulent wireless serving communication units or fraudulent networks can be more readily detected.
Abstract:
A wireless communication system (300) includes a wireless serving communication unit (322) serving a plurality of remote units (312-316) with a communication resource (318-320). The at least one wireless serving communication unit (322) includes a transmitter (421) for transmitting data on an outbound communication resource, and a receiver (422) for receiving a communication on an inbound communication resource, wherein said inbound and outbound communication resources have a variable communication resource offset. A communication unit, a broadcast message, a wireless serving communication unit and method of communication are also provided. By using a variable communication resource offset, the potential for a third party to jam a communication between the wireless serving communication unit and a remote communication unit is reduced.