Abstract: Forward power control during a soft handoff in a wireless communication system is accomplished by tracking each power command (PC) transmitted from a mobile unit to two or more base station transceiver systems (BTSs). Each BTS may interpret power commands differently due to noise. However, the power commands are relayed to a selector along with additional data transmitted in a conventional fashion. The selector determines the power levels of each BTS and transmits power charge commands to maintain power balance between the BTSs. The BTSs may transmit each PC command to the selector or accumulate several PC commands and send a PC history to the selector. The selector generates a reference PC history, which may be one of the PC histories transmitted from a BTS, a combination thereof, the result of data processing on the one or more PC histories.

Abstract: A method and apparatus for maintaining a target bit rate in a speech coder includes a speech coder for encoding a frame at a preselected encoding rate, computing a running average bit rate for a predefined number of encoded frames, subtracting the running average bit rate from a predefined target average bit rate, and dividing the difference by the preselected encoding rate. If the quotient value is negative, a predefined number of possible occurrence counts of speech coder performance threshold values that are less than a current performance threshold value is accumulated, the accumulated number being greater than the absolute value of the quotient. The product of a decrement-per-occurrence-count-value and the predefined number of occurrence counts is subtracted from the current performance threshold value to obtain a new performance threshold value.

Abstract: The present invention employs a method and apparatus for providing improved power control when changing the rate at which data is sent in a communications system. When data arrives at the transmitter for transmission at a high rate, power control feedback is changed from a slow mode (with a low bandwidth feedback channel) to a fast mode (with a high bandwidth feedback channel). This control changes even before the data is transmitted at the high rate. Once the power level is accurately estimated for data transmission at the high rate, then data transmission begins at the high rate.

Abstract: A method and apparatus for communicating both voice and control data between a communication device (such as a cellular phone) and an external accessory (such as a hands-free kit) over a data bus. The method includes formatting a sequence of bits into a repeating sequence of first time slots and second time slots, transmitting the voice data in the first time slot, and transmitting the control data in the second time slot. Notably, a first bit of each of the second time slots comprises a clock bit that alternates between a high value and a low value (e.g. a ‘1’ or a ‘0’) as between consecutive second time slots.

Abstract: An apparatus for accurate endpointing of speech in the presence of noise includes a processor and a software module. The processor executes the instructions of the software module to compare an utterance with a first signal-to-noise-ratio (SNR) threshold value to determine a first starting point and a first ending point of the utterance. The processor then compares with a second SNR threshold value a part of the utterance that predates the first starting point to determine a second starting point of the utterance. The processor also then compares with the second SNR threshold value a part of the utterance that postdates the first ending point to determine a second ending point of the utterance. The first and second SNR threshold values are recalculated periodically to reflect changing SNR conditions. The first SNR threshold value advantageously exceeds the second SNR threshold value.

Abstract: A method and apparatus for providing feedback from the decoder to the encoder to improve performance in a predictive speech coder under frame erasure conditions includes notifying an encoder in a receiving speech coder if a decoder in the receiving speech coder fails to receive a frame transmitted by an encoder in a transmitting speech coder. A modified packet is transmitted from the encoder in the receiving speech coder to a decoder in the transmitting speech coder in response to the notification. The decoder in the transmitting speech coder notifies the encoder in the transmitting speech coder when the modified packet is received. The encoder in the transmitting speech coder then encodes a packet with a modified encoding format. The modified encoding format may be either a low-memory encoding format or a memoryless encoding format. The modified packet may have an erasure indicator bit set to a digital value of one.

Abstract: A novel method is disclosed for the allocation of the capacity of a common channel among a number of data producers. In this method, a producer's future allocation grant is based on the extent to which the producer has used a previous allocation grant. The method is applicable to any system wherein the simultaneous use of a common channel by more than one producer may cause a data collision, and an exemplary application to the reverse link of a CDMA telecommunications system is described. Also disclosed are numerous variations and refinements concerning the estimation of remaining channel capacity, the distribution of such capacity among the various producers, and the use of its allocation grant by each producer.

Abstract: An amplitude quantization scheme for low-bit-rate speech coders includes the first step of extracting a vector of spectral information from a frame. The energy of the vector is normalized to generate gain factors. The gain factors are differentially vector quantized. The normalized gain factors are non-uniformly downsampled to generate a fixed-dimension vector with elements associated with a set of non-uniform frequency bands. The fixed-dimension vector is split into two or more sub-vectors. The sub-vectors are differentially quantized, to best advantage with a harmonic cloning process.

Abstract: A method and apparatus for maximizing the use of available capacity in a communication system having a base station and a plurality of mobile stations. The forward link in the mobile radio system includes a plurality of traffic streams sent on at least one channel from the base station to the mobile stations. The forward link is subject to a maximum power ceiling. A first output power level associated with simultaneously transmitting a first set of one or more traffic streams from the base station to the mobile stations on the forward link is initially determined. Next, the first output power level is compared to the maximum power ceiling. In response to the comparing step, at least one time frame in the forward link having available capacity for transmitting a portion of at least one further traffic stream is identified. The first set of traffic streams and the portion of the at least one further traffic stream are then transmitted simultaneously during the at least one frame on the forward link.

Abstract: A method for detecting delayed data frames in a transport function includes the steps of comparing a frame sequence counter with a predetermined threshold value, detecting a delayed frame if the sequence counter exceeds the threshold value, and processing the detected delayed frame accordingly. In an RLP data transport protocol, the delayed frame may be processed as a retransmitted frame. The threshold value may be proportional to the maximum number of frames sent in a given bundle times the maximum delay, in units of frame intervals, between frames sent simultaneously over the air in the same frame interval.

Abstract: A transmission method in a communications system has an orthogonal code vector for transmitting message signals. A first vector matrix is formed using a first series of cyclic shifts of a sequence having a characteristic polynomial wherein the characteristic polynomial of the sequence is a primitive polynomial having a degree r. A second vector matrix is formed using a second series of cyclic shifts in accordance with whether r is odd or even. The first vector matrix is permuted to provide an orthogonal code. The permuting operations are determined. The determined permuting operations are applied to the second matrix to provide a binary quasi orthogonal code vector. The binary quasi orthogonal code vector is applied to a message signal to provide an encoded message signal for transmission in the communications system. The transmission method also includes forming a vector matrix using a series of cyclic shifts of a sequence having a characteristic polynomial.

Abstract: Several methods and corresponding apparatus reduce peak to average power in signals transmitted in a wireless communications system, particularly with respect to pilot symbols transmitted from a base station to several user stations. A large peak to average amplitude of inserted pilot symbols has been found to result from a common sign chip position that exists in orthogonal codes, such as Walsh codes. In a first embodiment, the Walsh codes are multiplied by a random value of ±1. Under a second embodiment, the common sign chip position is eliminated in each Walsh code. The user station then inserts the missing chip position to regain orthogonality. In a third embodiment, the base station transmits pilot symbols, on a separate pilot channel, in only symbol positions that user stations expect to find pilot symbols. Under a fourth embodiment, each Walsh code is randomly shifted.

Abstract: In the present invention, the slave base station attains synchronization with the reference base station through messages transmitted from and received by a mobile station either in the soft handoff region between the reference base station and the slave base station or within a range which allows the mobile station to communicate with the slave base station. When the mobile station is not in communication with both the reference base station and the slave base station, then the round trip delay between the mobile station and the reference base station is measured by the reference base station. The reference base station communicates the PN code used by the mobile station over the reverse link to the slave base station. The slave bsae station acquires the signal from the mobile station and determines when the signal from the mobile station arrives. The slave base station then makes and estimate as to the length of the delay between transmission of a signal from the mobile station to the slave base station.

Abstract: A turbo code interleaver using linear congruential sequences may be employed as a two-dimensional interleaver in a turbo coder that also includes first and second constituent encoders. The interleaver and the first encoder are each configured to receive input bits. The first encoder produces output symbols therefrom. The interleaver receives the input bits sequentially by row. A linear congruential sequence recursion algorithm within the interleaver serves to pseudo-randomly rearrange, or shuffle, the bits within each row of the interleaver. The bits are then output from the interleaver sequentially by column. The second encoder is configured to receive the interleaved bits from the interleaver. The second encoder produces output symbols therefrom. The two streams of output symbols are multiplexed together, with appropriate puncturing. If desired, the linear congruential recursion sequence can be generated in reverse.

Abstract: The present invention is a novel and improved technique for performing coding with particular application to turbo, or iterative, coding techniques. In accordance with one embodiment of the invention, interleaving is performed by generating the address of a memory using a PN state generator. Data is written into a memory in sequential order, and then read out using addresses specified by the PN state generator. To deinterleave, the interleaved data is written into a memory using addresses specified by the PN state generator, and then read out in sequential order. A set of PN state generators that provide excellent coding performance is provided.

Abstract: A method and apparatus for performing inter-system hard handoff between communication systems or inter-frequency hard handoff within a CDMA communication system is disclosed. The purpose of this invention is to reduce the probability of dropped calls during inter-system hard handoff. In the event that a hard handoff attempt is unsuccessful, the mobile station will return to the original system with information which the communication system of the present invention uses to assist in the performance of future handoff attempts. Alternatively, with no handoff attempt made, the mobile station monitors the destination system then returns to the original system with information used to assist in subsequent handoff attempts. The information returned from monitoring a CDMA system consists of results of a search for one or more pilots given at offsets in a specific list provided to the mobile station by the base station or a set of offsets based upon a predetermined search algorithm.

Abstract: The punctured pilot channel comprises information symbols of uncertain sign punctured into a sequence of pilot channel symbols of predetermined sign. The apparatus includes an information sign demodulation circuit for determining the sign of the information symbols in response to the pilot channel symbols. A continuous pilot generator generates a non-punctured pilot channel of predetermined sign from the information symbols and the pilot channel symbols. In a first embodiment, the information sign demodulator further comprises a dot product circuit for calculating a dot product of the pilot channel symbols and the punctured information symbols, and a threshold comparator for comparing the dot product to a predetermined threshold.

Abstract: A novel and improved method for implementing a high-transmission-rate over-the-air interface is described. A transmit system provides an in-phase channel set and a quadrature-phase channel set. The in-phase channel set is used to provide a complete set of orthogonal medium rate control and traffic channels. The quadrature-phase channel set is used to provide a high-rate supplemental channel and an extended set of medium rate channels that are orthogonal to each other and the original medium rate channels. The high-rate supplemental channel is generated over a set of medium rate channels using a short channel code. The medium rate channel are generated using a set of long channel codes.

Abstract: A system and method for forming a segmented speech signal from an input speech signal having a plurality of frames. The input speech signal is converted from a time domain signal to a frequency domain signal having a plurality of speech frames, wherein each speech frame in the frequency domain signal is represented by at least one spectral value associated with the speech frame. A spectral difference value is then determined for each pair of adjacent frames in the frequency domain signal, wherein the spectral difference value for each pair of adjacent frames is representative of a difference between the at least one spectral value associated with each frame in the pair of adjacent frames. An initial cluster boundary is set between each pair of adjacent frames in the frequency domain signal, and a variance value is assigned to each cluster in the frequency domain signal, wherein the variance value for each cluster is equal to one of the determined spectral difference values.

Abstract: Independently controlling the transmitted power of each subchannel by a subchannel control loop is described. A transmitting station generates a channel made up of a sum of subchannels wherein each subchannel or group of subchannels is amplified with a unique gain value that is varied in accordance with subchannel power control messages from the receiving station. The receiving station generates each subchannel power control message subsequent to monitoring and calculating metrics based on that received subchannel.