Abstract: A mobile station accesses a base station by randomly selecting a first reverse link common control channel from a set of random access channels. The mobile station transmits a request portion of an access probe over the first reverse link common control channel. The request portion is subject to collision with other signals. The request portion comprises a hash identification which is derived from a uniquely identifying number using a hash function. The hash identification quasi-uniquely identifies the mobile station. The mobile station receives a channel assignment message from the base station designating the hash identification and a reserved access channel. The reserved access channel provides communication with a low probability of contention. The mobile station transmits a message portion of the access probe over the reserved access channel.

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: A system for enhancing low frequency spectral content of a digitized signal which identifies a fundamental frequency component in the signal and selectively boosts signals within a predetermined range thereof. In the illustrative embodiment, the digitized signal is a frequency domain transformed speech signal. The invention amplifies the low frequency components of the speech signal. The speaker unique fundamental frequency of the speech is computed using pitch delay information and is thus dynamic from frame to frame and also speaker to speaker. This fundamental frequency defines the center point of a gain window which is applied to select frequency components. Only such fundamental frequency components which exhibit a large enough signal to noise ratio have the amplification function applied. Thus, this function can be applied directly following a noise suppression system which has knowledge of the signal quality in each frequency bin.

Abstract: A communication network having a plurality of subscriber units that receive a finite resource from a common node is disclosed. Individual subscriber units may seize the finite resource of the common node to the exclusion of all other subscriber units in the network. A scheduler allocates the finite resource to the individual subscriber units based upon a weight associated with the individual subscriber units. The scheduler determines the weight for each of the subscriber units based upon an instantaneous rate of consuming the finite resource.

Abstract: A method and apparatus for eighth-rate random number generation for speech coders includes a random number generator configured to generate values of a first random variable. A lookup table is used to store values of a second random variable. The lookup table is addressed with the values of the first random variable. The second random variable is an inverse transform of a cumulative distribution function of the first random variable. An codec encodes input silence frames with the values of the first and second random variables, and regenerates the silence frames with the values of the first and second random variables. The speech coder may be an enhanced variable rate coder, and the silence frames may be encoded at eighth rate. The random variables are advantageously Gaussian random variables with values that are uniformly distributed between zero and one.

Abstract: Techniques for detecting zero rate frames in a received data transmission. A modulated signal is received and demodulated in accordance with a particular demodulation format to generate demodulated symbols. The demodulated symbols are partitioned into a number of received frames. For each received frame, a quality metric is computed and compared against a threshold value. The threshold value is selected based, in part, on the quality metrics of received frames. Based on the comparison result, the received frame is indicated as being either transmitted and received in error (i.e., erased or bad) or not transmitted at all (i.e., zero rate or empty). The quality metric can relate to an energy of a received frame, a distance between a received frame and a codeword corresponding to the received frame, or other metrics.

Abstract: A hands free telephone system includes a telephone having audio circuits for processing an audio signal and a telephone audio connector for transmitting the audio signal between the audio circuits and the telephone audio connector. A telephone holder has a holder program for instructing the telephone holder to perform telephone functions in accordance with the stored program. The telephone holder has a holder audio connector for mechanically mating with the telephone audio connector and transmitting the audio signal between the telephone audio connector and the programmable holder.

Abstract: A method and apparatus for controlling a data rate associated with the transmission of information from a base station to a mobile station in a mobile radio communication system. The mobile station alternately receives information from a base station either in a variable rate mode or a fixed rate mode. The transmission rate from a base station in the variable rate mode varies between successive data transmit intervals, and the transmission rate from a base station in the fixed rate mode remains fixed between successive data transmit intervals. Data is transmitted from a first base station to the mobile station in the variable rate mode until the first base station is unable to receive variable data rate control information from the mobile station.

Abstract: The mobile telephone detects bad data packets by decoding speech parameters represented by the packets and comparing those speech parameters against acceptable ranges of speech parameters. If the speech parameters do not lie within the acceptable ranges, the packets are discarded. This speech parameter-based detection of bad data packets is particularly useful in mobile telephones receiving variable rate data packets wherein an error in determining the rate of a packet results in the entire packet being decoded at an incorrect rate, thereby likely causing an annoying audible artifact in the decode speech signal. Such rate detection errors can occur even though a CRC or other conventional error detection check fails to detect the bad packet. In an exemplary implementation, the mobile telephone receives signals encoded with TIA/EIA/IS-95-A standards.

Abstract: The invention provides technology that improves the security of the A-Keys in a wireless communications system. The technology effectively prevents any human access to the A-Keys and eliminates cloning. The invention improves the security and integrity of the wireless communications system. A secure processor exchanges random numbers with a wireless communications device to generate the A-Key. The secure processor then encrypts the A-Key and transfers the encrypted A-Key to an authentication system. When the authentication system generates or updates the SSD, the authentication system transfers the encrypted A-Key and other information to the secure processor. The secure processor decrypts the A-Key and calculates the SSD. The secure processor transfers the SSD to the authentication system for use in authenticating the wireless communications device.

Abstract: The signal strength of a received signal in a communication system is estimated by the measured signal strength of a desired signal which is transmitted from a source device to a destination device. The energy of the desired signal and the energy of the noise are measured or computed. The measured signal strength can be computed by dividing the energy of the desired signal with the energy of the noise. The signal strength of the desired signal can be estimated as the maximum likelihood estimate of the actual signal strength &agr;. The signal strength of the desired signal can also be estimated based on the expected value of the energy of the desired signal. The signal strength of the desired signal can further be estimated based on the expected value of the energy of the desired signal and accounting for a predetermined bias.

Abstract: A system and method for providing mobile switching center (MSC) initiated service negotiation in a wireless communication system. If a new call arrives for a subscriber unit while the subscriber unit is already on the traffic channel, a change in the service configuration may allow the subscriber unit to receive the new call while preserving the old call. MSC initiated service negotiation may be used to establish the change in service configuration. The MSC transmits a Change Service Command message to the base station in whose coverage area the subscriber unit is located. The Change Service Command proposes a new service configuration to accommodate both the old and the new call. The base station, subscriber unit, and MSC may interchange further messages to modify the proposed service configuration if necessary. Messages are exchanged until the base station, subscriber unit, and MSC reach an agreement regarding the new service configuration. The present invention also provides support for soft handoff.

Abstract: In a wireless communication system, in order to determine a level of loading, the system enters a period of silence during which a designated remote unit continues to transmit but other remote unit transmissions are interrupted. The base station and designated remote unit perform closed loop power control on a reverse link signal received from the designated remote. A first series of power control commands accumulated and a first corresponding transmit gain adjustment value is stored. Normal operation is resumed. Once again, the base station and designated remote unit perform closed loop power control on the reverse link signal received from the designated remote unit. A second series of power control commands are accumulated and a second corresponding transmit gain adjustment value is stored. A level of loading is determined based upon the first and second transmit gain adjustment values.

Abstract: A method and apparatus for normalizing a plurality of state-metric registers in a decoder using a trellis. The method includes determining an approximate minimum of respective state-metric values stored in the plurality of state-metric registers, and subtracting the approximate minimum from the values. Determining the approximate minimum preferably includes determining the minimum of a predetermined number of most significant bits in the plurality of state-metric registers.

Abstract: A system and method for performing base station initiated call setup is provided. A base station initiated call setup may be utilized to establish a test call, to deliver a packet data services call to a subscriber unit, or to reactivate a dormant packet call. The base station transmits a BS Service Request message to the mobile switching center, requesting initiation of the call. The mobile switching center will authorize the call if the call to be set up is directed to a subscriber unit located within the service area of the base station and if the service option to be used is authorized for the particular subscriber unit. The mobile switching center will allow or disallow the call depending on the state of the subscriber unit. The mobile switching center transmits a BS Service Response message to the base station, conveying the result of processing the BS Service Request message.

Abstract: A method and system for allocating a set of orthogonal PN code sequences of variable length among user channels operative at different data rates in a spread spectrum communication system is disclosed herein. PN code sequences are constructed that provide orthogonality between users so that mutual interference will be reduced, thereby allowing higher capacity and better link performance. In an exemplary embodiment, signals are communicated between a cell-site and mobile units using direct sequence spread spectrum communication signals. Information signals communicated on the cell-to-mobile link channels are encoded, interleaved, and modulated with orthogonal covering of each information symbol. Orthogonal Walsh function codes of varying length are employed to modulate the information signals. Code assignments are made on the basis of channel data rates in a manner which results in improved utilization of the available frequency spectrum.

Abstract: A voice mail system is provided in a CDMA wireless telephone system in which a base station controller (BSC) stores, in a encoded format, voice data transmitted by a wireless telephone to a receiving telephone, either wireless or fixed telephone, when the receiving telephone does not “pick up”. Also, the base station controller encodes and then stores voice data that is transmitted by a fixed telephone to a wireless telephone when the wireless telephone does not “pick up”. In either case, to retrieve voice mail the intended recipient can access the voice mail from a fixed telephone, in which case the voice mail is decoded at the BSC and then sent to the fixed telephone via a landline. Alternatively, the intended recipient can access the voice mail from a wireless telephone in the system, in which case the voice mail is not decoded at the BSC, but is transmitted directly to the wireless telephone, where the message is decoded.

Abstract: Apparatus for iterative decoding of a sequence of signal packets coded in accordance with a multi-component coding scheme. The apparatus includes a plurality of decoders, each of which performs a respective different decoding method on one of the signal packets, such that the plurality of decoders operate substantially concurrently. Iterative decoding may be stopped if a predefined threshold maximum number of iterations is reached, or if the previous two decoder iterations have satisfactory cyclic redundancy checks (CRC), or if the input frame buffer to the decoder is filled to within a predefined percentage of its storage capacity.

Abstract: In a mobile communication system having a first communication device for communicating with a plurality of second communication devices, a method for performing handoff within the mobile communication system includes transmitting from at least one of the second communication devices to the first communication device a handoff list of second communication devices to which the first communication device is permitted to handoff. A channel assignment message is transmitted from each of the second communications devices in the handoff list. The handoff list includes base stations controlled by a single controller that determines which of the second communication devices transmits the channel assignment message. The base stations on the handoff list have pilot signals and the energy levels of the pilot signals are measured by the first communication device.

Abstract: A method and apparatus for determining the rate of received data in a variable rate communication system. The receiving system decodes each frame of the received signal to produce a set of normalized correlation metrics, cyclic redundancy check (CRC) bits, and possibly Yamamoto quality metrics, one for each possible data rate. The normalized correlation metric for each rate is calculated from a correlation value an a constant computed for that rate. The correlation value is determined from a correlation of the demodulated soft frame symbols and the re-encoded frame. The highest normalized correlation metric is selected and the CRC bit for this data rate is checked. If the CRC checks, this data rate is indicated as the received data rate. Otherwise, the next highest normalized correlation metric is selected and the process continues. If no CRC check, an erasure is indicated.