Abstract:
The present invention discloses a variable rate transmission system wherein a packet of variable rate data generated by a variable rate data source (20) is modulated on traffic channel by traffic channel modulator (30) if the capacity of said traffic channel is greater than or equal to said data rate of said packet. The packet of variable rate data is modulated onto traffic channel by traffic channel modulator (30) and at least one overflow channel by traffic channel modulator (32) if the capacity of said traffic channel is less than said data rate. The present invention further discloses a receiving system for receiving variable rate data wherein a received packet of variable rate data is received on traffic channel if the capacity of said traffic channel is greater than or equal to a data rate of said packet and wherein a packet of variable rate data is received on traffic channel and at least one overflow channel if the capacity of said traffic channel is less than said data rate.
Abstract:
A method and apparatus for controlling transmission power in a mobile communication system is disclosed. The method disclosed provides for a closed-loop power control method. A mobile station (30) provides information on the quality of the signal received from the base station (50), and the base station (50) responds by adjusting the power allocated to that user in a shared base station signal. The transmission power is adjusted initially by a large increment and then ramped down at an increasingly decreasing rate. The mobile station (30) also provides information to the base station (50) as to its relative velocity and the base station (50) adjusts its transmission power in accordance with this velocity information.
Abstract:
A system for monitoring and the adjustment of control unit parameter settings of vehicle electronic control units (44, 45). The monitoring system may be implemented in a vehicle (12, 14) in which are incorporated one or more electronic control units (44, 45) for regulating one or more operational parameters of the vehicle (12, 14) in accordance with corresponding control unit parameter settings. In an exemplary implementation the vehicle (12, 14) is equipped with a mobile communications terminal, MCT (38), which receives from a base station (18) a list of operational parameters to be monitored. Each of the electronic control units (44, 45), as well as a memory unit (62), are connected to an internal data link (40) of the vehicle. When a parameter value within the memory unit (62) corresponding to a given electronic control unit (44, 45) is changed, a message is provided to the base station (18) specifying the value currently registered by the particular electronic control unit (44, 45). The currently registered value is then compared to an expected parameter value, and an error message is generated if disagreement exists therebetween. The system also allows vehicle electronic control unit parameter settings to be adjusted from a remote location such as a base station (18).
Abstract:
A method and apparatus for arranging various types of data, and at various rates, into a uniquely structured format for transmission. Data for transmission formatting may be speech data provided by vocoder (14) or different types of secondary traffic. The data organized into frames of a predetermined time duration for transmission by a microprocessor (18). The data frames are organized, depending on the data, to be at one of several data rates. Vocoder data is provided by vocoder (14) at one of several data rates and is organized in the frame according to a predermined format. Frames may be formatted with a sharing of vocoder data with non-vocoder data to be at a highest frame data rate. Different types of non-vocoder data may be organized so as to also be at the highest frame data rate. Additional control data may be provided within the data frames to support various aspects of the transmission and recovery upon reception.
Abstract:
The invention provides a system and method for testing signal transmission quality wihin a digital communication system and may be incorporated within a digital cellular communication system in which information is exchanged over spread spectrum communication channels. A test sequence of digital data transmitted over the communication channel is received at a receiving station, within which is also generated a replica of the test sequence of digital data. The accuracy of transmission over the communication channel is then determined by comparing the replica of the test sequence of digital data to the test sequence of data received over the communication channel. The invention allows the test sequence of digital data to be transmitted at one of a set of known data rates, with the received station being disposed to identify the data rate associated with each test sequence of digital data. In order to simulate the transmission of, for example, voice data, the system may be configured such that each test sequence of digital data is generated in accordance with a pseudorandom process.
Abstract:
An apparatus and method for adding and removing a target base station from a network of base stations, which includes base stations adjacent the target base station. The apparatus is comprised of two attenuators: a first (210) for setting an artificial receive noise power level and a second (218) for setting a transmit level. The transmit level determines the forward link coverage area of the base station. The artificial noise level sets the reverse link coverage area of the base station. When a base station is added, initially the transmit power is low and the artificial receive noise power is high such that the forward and reverse link coverage areas are collocated in close proximity to the base station. As the base station blossoms into full operation, the artificial receive noise power is decreased and the transmit level is increased such that the two coverage areas of the base station remain balanced as the coverage areas expand. When a base station is to be removed from a system, the same attenuators are used to wilt the two coverage areas in unison as the power level transmitted from the base station decreases.
Abstract:
The present invention provides a method by which to reduce the probality of coding low energy unvoiced speech as background noise. An encoding rate is determined by dividing the input signal into subbands using digital subband filters (4) and (6) and comparing the energy in those bands to a set of thresholds in subband rate decision elements (12) and (14) and then examining those comparisons in an encoding rate selector (16). By this method, unvoiced speech can be distinguished from background noise. The present invention, also, provides a means for setting the threshold levels using the signal to noise ratio of the input signal, and the present invention provides a method for coding music through a variable rate vocoder by examining the periodicity of the input signal to distinguish the music from background noise.
Abstract:
A method and an apparatus for controlling transmission power in a variable rate communication system. A base station (30) monitors the reverse link signal transmitted from a mobile station (50). Base station (30) determines whether mobile station (50) should increase or decrease its power based either upon frame error rates detected by a decoder (44) or by the level of received signal power detected at a receiver (42). In response to this analysis, a control processor (46) generates a power control signal and transmits this signal to mobile station (30).
Abstract:
The invention provides a layered channel software element (200) which supervises the operation of channel element modem resources (59) in a CDMA cellular telephone system (8) that includes forward channels (20a, 22a) for conveying message and signalling data from a CDMA system base station (12) to mobile units (16, 18) and reverse channels (20b, 22b) for conveying message and signalling data from mobile units (16, 18) to base stations (12, 14). Each channel is implemented in a channel element (59) including a general purpose processor (60) and a modem application-specific integrated circuit ASIC (62). The layered channel software element (200) executes on the general processor (60). The layered channel software element (200) provides a structure and function for transferring message and signalling data between the telecommunication system (10) and the modem ASIC (62) via channel element controller (44), and also for establishing channel operations by providing channel configuration information to the modem ASIC (62).
Abstract:
An automatic gain control (AGC) and D.C. offset correction method and apparatus for controlling signal power of a received RF signal within a dual mode quadrature receiver is disclosed herein. The AGC apparatus includes an adjustable gain amplifier (18). A quadrature downconverter (20) coupled to the amplifier (18) serves to translate the frequency of the output signal to a baseband frequency which is offset by a predetermined margin from D.C. Two high gain active lowpass filters (76 and 78) provide out-of-band signal rejection for the baseband signals. A D.C. feedthrough suppression loop supresses D.C. offsets produced by a downconverter (20) and the lowpass filters (76 and 78). The AGC apparatus also generates a received power signal based on the power of the output signal. A saturating integrator compares the received power signal to a reference signal and produces the gain control signal by integrating or by refraining from integration based on values of the reference, received power signal, and gain control signals.