Abstract: A communications network and method for over the air service programming a mobile station (2), where the mobile station transmits a service programming request to a communications network, which results in the mobile station (2) being connected to a customer service center (26). Customer service center (26) queries the user of mobile station (2) for information in response to which the customer service center (26) selects a home location register (18) and authentication center (22) within the communication network with which the mobile station (2) is to be associated. Service programming information associated with the mobile station (2) is transferred from the home location register (18) and/or the authentication center (22) into mobile station (2).

Abstract: A method and apparatus for reducing transmission delay in a wireless communication system that carries packetized voice and data information. Interruptions in the traffic channels cause loss of synchronization between a header compressor and a header decompressor. Rather than transmitting resynchronization information on the traffic channel, the information dropped by an interruption is re-transmitted on a non-traffic channel in parallel with the traffic channel. At the remote station, information from the traffic channel and the non-traffic channel is reassembled before input into the decompressor. Alternatively, the non-traffic channel can be used to carry overflow information so that a higher average data rate can be achieved than the average data rate of the traffic channel alone.

Abstract: The certainties of transmitted bits at predetermined locations in time are determined a priori. This information is then used to set the states of a Viterbi decoder to different state metrics in accordance with the certainties of the transmitted bits. High certainty of a transmitted bit results in resetting the states corresponding to that bit to a high state metric. In contrast, low certainty of a transmitted bit results in resetting the states corresponding to that bit to a low state metric. Resetting the states to different state metrics improves the decoding performance and shortens the time required to converge the decoding trellis by eliminating improbable paths.

Abstract: A method and apparatus for generating encryption stream ciphers. The recurrence relation is designed to operate over finite fields larger than GF(2). The linear feedback shift register used to implement the recurrence relation can be implemented using a circular buffer or sliding a window. Multiplications of the elements of the finite field are implemented using lookup tables. A non-linear output can be obtained by using one or a combination of non-linear processes. The stream ciphers can be designed to support multi-tier keying to suit the requirements of the applications for which the stream ciphers are used.

Abstract: A method and an apparatus for generating encryption stream ciphers are based on a recurrence relation designed to operate over finite fields larger than GF(2). A non-linear output can be obtained by using one or a combination of non-linear processes to form an output function. The recurrence relation and the output function can be selected to have distinct pair distances such that, as the shift register is shifted, no identical pair of elements of the shift register are used twice in either the recurrence relation or the output function. Under these conditions, the recurrence relation and the output function also can be chosen to optimize cryptographic security or computational efficiency.

Abstract: In a half-duplex communication system in which additional delays in the communication channel may cause a message collision between a message and a response, a collision detector is utilized to prevent and detect message collisions. The collision detector determines if a response may be transmitted from the communication device while it is receiving the current message. If no response is expected, the collision detector is placed into a train mode. If a response is possible, the collision detector is placed into the monitor mode. In the monitor mode, the collision detector monitors the communication channel and determines if a message collision has occurred during transmission of the message. A detection of a message collision causes retransmission of the message or possibly a new message at a later time after it has been determined that the communication channel is clear.

Abstract: It is an objective of the present invention to provide an optimized method of selection of the encoding mode that provides rate efficient coding of the input speech. It is a second objective of the present invention to identify and provide a means for generating a set of parameters ideally suited for this operational mode selection. Third, it is an objective of the present invention to provide identification of two separate conditions that allow low rate coding with minimal sacrifice to quality. The two conditions are the coding of unvoiced speech and the coding of temporally masked speech. It is a fourth objective of the present invention to provide a method for dynamically adjusting the average output data rate of the speech coder with minimal impact on speech quality.

Abstract: A method and apparatus for balancing the forward link capacity of a wireless communication system with the reverse link capacity of the system is presented. Speech coders with selectable modes are implemented in both links so that a forward link speech coder will not be operating with a mode set that is identical to the mode set used by a reverse link speech coder. Since the reverse link has a higher user capacity than a forward link, the reverse link speech coder can operate with a higher average data rate. Hence, the mode set used by the reverse link speech coder can be implemented without low average data rate modes. Elimination of modes from the mode set reduces complexity of the speech coder.

Abstract: A method and apparatus for coding a quasi-periodic speech signal. The speech signal is represented by a residual signal generated by filtering the speech signal with a Linear Predictive Coding (LPC) analysis filter. The residual signal is encoded by extracting a prototype period from a current frame of the residual signal. A first set of parameters is calculated which describes how to modify a previous prototype period to approximate the current prototype period. One or more codevectors are selected which, when summed, approximate the error between the current prototype period and the modified previous prototype. A multi-stage codebook is used to encode this error signal. A second set of parameters describe these selected codevectors. The decoder synthesizes an output speech signal by reconstructing a current prototype period based on the first and second set of parameters, and the previous reconstructed prototype period.

Abstract: A method and apparatus for using coding scheme selection patterns in a predictive speech coder to reduce sensitivity to frame error conditions includes a speech coder configured to select from among various predictive coding modes. After a predefined number of speech frames have been predictively coded, the speech coder codes one frame with a nonpredictive coding mode or a mildly predictive coding mode. The predefined number of frames can be determined in advance from the subjective standpoint of a listener. The predefined number of frames may be varied periodically. An average coding bit rate may be maintained for the speech coder by ensuring that an average coding bit rate is maintained for each successive pattern, or group, of predictively coded speech frames including at least one nonpredictively coded or mildly predictively coded speech frame.

Abstract: A method and apparatus for negotiating service configuration in a digital communication system is disclosed. In an exemplary embodiment the service negotiation system is implemented in a wireless spread spectrum communication system. The service configuration comprises data rates, frame formats and types of services. Types of service may include speech encoding, facsimile or digital data services. Further described herein is a digital transmitter and receiver using the service negotiation system to provide service configuration mutually acceptable at both ends of a communication link.

Abstract: In a communications system, a method of transforming a set of message signals representing a message comprising the steps of first encoding one of the set of message signals in accordance with a first keyed transformation, a second encoding of the one of the set of message signals in accordance with at least one additional keyed transformation, a third encoding of the one of the set of message signals in accordance with a self inverting transformation in which at least one of the set of message signals is altered, a fourth encoding of the one of the set of message signals in accordance with at least one additional inverse keyed transformation wherein each of the at least one additional inverse keyed transformation is a corresponding inverse of at least one additional keyed transformation, and fifth encoding the one of the set of message signals in accordance with first inverse keyed transformation wherein the first inverse keyed transformation is the inverse of the first keyed transformation.

Abstract: A communications network and method for over the air service programming a mobile station (2), where the mobile station transmits a service programming request to a communications network, which results in the mobile station (2) being connected to a customer service center (26). Customer service center (26) queries the user of mobile station (2) for information in response to which the customer service center (26) selects a home location register (18) and authentication center (22) within the communication network with which the mobile station (2) is to be associated. Service programming information associated with the mobile station (2) is transferred from the home location register (18) and/or the authentication center (22) into mobile station (2).

Abstract: The present invention provides an apparatus and method for supporting analog fax calls between two wireless subscriber stations in a tandem configuration. The existence of a tandem configuration is detected, and a more efficient communication protocol is established between two base stations upon detection of the tandem configuration. A message generator in a first base station generates an identification message. If the identification message is received by a second base station, the second base station will be informed that the tandem configuration exists. A message generator in a second base station may then generate a return message, which when received by the first base station, will notify the first base station of the existence of the tandem configuration. To support the tandem configuration, full duplex communication may be established between the two base stations.

Abstract: A method and apparatus for generating encryption stream ciphers. The recurrence relation is designed to operate over finite fields larger than GF(2) and is maximal length. An output equation generates the output based on a plurality of elements in the shift register used to implement the recurrence relation. The recurrence relation and the output equation are selected to have distinct pair distances such that, as the shift register shifts, no particular pair of elements of the shift register are used twice in either the recurrence relation or the output equation.

Abstract: It is an objective of the present invention to provide an optimized method of selection of the encoding mode that provides rate efficient coding of the input speech. It is a second objective of the present invention to identify and provide a means for generating a set of parameters ideally suited for this operational mode selection. Third, it is an objective of the present invention to provide identification of two separate conditions that allow low rate coding with minimal sacrifice to quality. The two conditions are the coding of unvoiced speech and the coding of temporally masked speech. It is a fourth objective of the present invention to provide a method for dynamically adjusting the average output data rate of the speech coder with minimal impact on speech quality.

Abstract: In a communication system which conforms to the IS-99 standard, a concatenated code is used to provide for error free file transfer over the air. The concatenated code comprises Reed-Solomon coding, CRC block coding, and convolutional coding. The file is partitioned into data frames and Reed-Solomon encoding is performed on the data frames. CRC block encoding is then performed on the Reed-Solomon encoded data. The CRC encoded data is convolutionally encoded. The CRC block encoding and convolutional encoding are performed in accordance with the IS-99 standard. The additional Reed-Solomon encoding step provides improved error correction capability while maintaining compatibility with the IS-99 standard. At the receiver, Reed-Solomon decoding is performed if the number of erasures in a code word is less than or equal to (n−k) or the symbol errors in a code word is less than or equal to (n−k)/2. Otherwise, a request for retransmission is sent.

Abstract: A method and apparatus for controlling the transmit power of a plurality of mobile radio units transmitting to a base station in a mobile radio telephone system. For each of the mobile units in the system, a signal strength estimate is measured at the base station based on reverse link signals sent from the mobile units and received at the base station, wherein each signal strength estimate is associated with one of the mobile units. The signal strength estimate associated with each mobile unit is compared to a threshold. Next, for each mobile unit in the plurality of mobile units, if the signal strength estimate associated with the mobile unit is greater than the threshold, then a power control bit having a first value is assigned to the mobile unit; conversely, if the signal strength estimate associated with the mobile unit is less than the threshold, then a power control bit having a second value is assigned to the mobile unit.

Abstract: A method and apparatus to facilitate service negotiation by a digital telecommunications system that allows a low activity communication to be transmitted by the system over vocoded channels. In one embodiment, once the telecommunication system is noticed that a low activity signal needs to be transmitted, each telecommunication system vocoder involved in the transmission automatically locks into full rate, and where applicable, adjusts the transmission power to reduce frame error rate. Further, the telecommunications system may include any number of wireless links. The invention includes a noticing apparatus coupled to a sensor that receives a low activity communication device attachment and notices the digital telecommunications system that a low activity communication is being initiated or discontinued.

Abstract: The certainties of transmitted bits at predetermined locations in time are determine a priori. This information is then used to set the states of a Viterbi decoder to different state metrics in accordance with the certainties of the transmitted bits. High certainty of a transmitted bit results in resetting the states corresponding to that bit to a high state metric. In contrast, low certainty of a transmitted bit results in resetting the states corresponding to that bit to a low state metric. Resetting the states to different state metrics improves the decoding performance and shortens the time required to converge the decoding trellis by eliminating improbable paths.