Abstract: A channel structure for use in communication systems. Two sets of physical channels, one for the forward link and another for the reverse link, are utilized to facilitate communication of a variety of logical channels. The physical channels comprise data and control channels. In the exemplary embodiment, the data channels comprise fundamental channels which are used to transmit voice traffic, data traffic, high speed data, and other overhead information and supplemental channels which are used to transmit high speed data. The fundamental channels can be released when the remote stations are idle to more fully utilized the available capacity. The control channels are used to transmit paging and control messages and scheduling information.

Abstract: A receive filter receives signals from a communication channel. The received signals correspond to original Walsh covered chip sequences transmitted by a transmit filter through the communication channel to the receive filter. The received signals are processed by an equalizer to generate a soft estimate of chip sequences corresponding to the original Walsh covered chip sequences. An N chip Walsh decover is then utilized to generate a soft estimate of code symbols corresponding to the soft estimate of the chip sequences. A number of symbol slicers are then used in parallel to produce a hard estimate of the code symbols corresponding to the soft estimate of code symbols generated by the N chip Walsh decover. Thereafter an N chip Walsh cover is used as part of a scheme to generate a hard estimate of chip sequences corresponding to the hard estimate of the code symbols generated by the symbol slicers.

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: Method and apparatus for adjusting the transmission power of base stations in simultaneous communication with a mobile station. The methods described provide for the transmission power of the base stations to be aligned. In the first exemplary embodiment, the transmitters are attached to a separate control unit through communication links. The control unit then derives the most likely command stream and send that to the base stations. In the second exemplary embodiment, the control unit periodically receives the final or average transmit level in a period and an aggregate quality measure for the feedback during a period from each of the transmitters. The control unit determines the aligned power level and transmits a message indicative of the aligned power level to the transmitters. In the third exemplary embodiment, the transmitters send the control unit a message indicative of the transmit power of transmissions to the receiver.

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: An improved method and system for transmitting a stream of data bytes through a channel whose capacity may change during transmission. By utilization of selective regions of sequence number space, the enhanced radio link protocol (RLP) provides the benefits of large byte sequence numbers while transmitting a fraction of the sequence number bits in the majority of over-the-air frames. Frame header sequence numbers are shortened by dividing the byte sequence number by a page size, and by performing a modulo function on the byte sequence number.

Abstract: A system for accessing broadcast SMS messages over a wireless communication system. A base station transmits SMS messages periodically and aperiodically over a broadcast channel. The base station allocates periodic slots in the broadcast channel for each of the subscriber services providing the SMS messages and transmits slot parameters to mobile units. Using the slot parameter information, the mobile units periodically wake up to scan the broadcast channel. The period for each category of broadcast SMS messages may be different and the period may apply to a single broadcast channel. Messages arriving aperiodically can be queued and transmitted in pre-scheduled broadcast channel frames. Messages with inter-arrival interval greater than the specified transmission period are simply repeated.

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 method and apparatus for transmitting digital data in a cellular environment. Adjacent cells of the cellular system are prevented from simultaneously transmitting data. Because the noise from transmissions of adjacent cells is a primary source of interference, the transmission rate of power limited base stations can be dramatically increased when the noise from adjacent cells is eliminated. The transmissions to each subscriber station are made at a fixed transmission power level. However, the data rate of transmitted signals differs from one subscriber station to another depending the path loss differences. In a first exemplary embodiment, the data rate of transmissions to a subscriber station is determined by selecting an encoding rate for the transmitted signal while holding the symbol rate constant.

Abstract: The present invention is a novel and improved method and system for communicating a frame of information according to a discontinuous transmit format. In particular, the present invention describes a method of transmitting eighth rate speech or data frames employing transmit gating and energy scaling which simultaneously reduces the battery usage of a variable rate wireless communication device, increases the capacity of the reverse link and provides reliable communication of the eighth rate frames. In the present invention, four methods are presented for transmitting an eighth rate data frame in which half of the frame is gated out and the remaining data is transmitted at nominal transmission energy to accomplish the aforementioned goals. In addition, a power control system in which identifies forward link power control bits that .1have been gated out by the remote station and inhibits adjustment of the transmission energy in response to that identification is disclosed.

Abstract: A method and circuit for adaptively estimating channel conditions of a pilot channel in a wireless communication system. The method includes estimating channel statistics of the pilot channel, and adaptively filtering the pilot channel in response to the estimated channel statistics. The estimation is performed by filtering a channel signal derived from the pilot channel to determine an estimated channel mean and an estimated channel covariance. In order to perform the adaptive filtering, the present invention partitions the pilot channel into one or more time slots and weights each time slot according to the channel statistics. Thus, an advantage of the present invention is that it automatically and continually updates the pilot filter parameters in order to optimize the pilot filter performance over a broad range of channel conditions.

Abstract: In some aspects, each cell in the communications system can be designed to operate in accordance with a set of back-off factors that identify the reductions in peak transmit power levels for the channels associated with the back-off factors. The back-off factors are defined to provide the required power to a large percentage of the users while reducing the amount of interference. In some other aspects, the cells operate using an adaptive reuse scheme that allows the cells to efficiently allocate and reallocate the system resources to reflect changes in the system. A reuse scheme is initially defined and resources are allocated to the cells. During operation, changes in the operating conditions of the system are detected and the reuse scheme is redefined as necessary based on the detected changes. For example, the loading conditions of the cells can be detected, and the resources can be reallocated and/or the reuse scheme can be redefined.

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: A base station architecture splits modem functionality into modulator and demodulator entities, each configured to handle multiple telephone calls. A high-speed digital bus with associated routing elements connects multiple-channel (i.e., multiuser) modulator and demodulator elements. The modulator and demodulator elements may be physically separated, residing on different cards, and even different shelves, within the base station. On each modulator card, the outputs of multiple modulators may be combined by digitally upconverting the output of each modulator by a different amount and summing the results.

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 supervising a dedicated control channel when in the discontinuous transmission mode. The mobile station monitors the frames it receives from a base station and maintains a counter of bad, good, and empty frames, referred to as COUNT1, COUNT2, COUNT3, respectively. If a received frame is a good frame, COUNT1 is reset to zero and COUNT2 is incremented. If the received frame is a bad frame, COUNT1 is incremented and COUNT2 is reset to zero. If the received frame is an empty frame, COUNT1 and COUNT2 are unchanged but COUNT3 is incremented. A transmitter coupled to the mobile station is enabled or disabled depending upon which, if any, of the COUNTs reaches or exceeds a designated threshold value. In another embodiment, an average aggregated value reflecting the strength of the pilot signals in an active set, measured at the mobile station, is used for comparison to a threshold.

Abstract: The present invention is a novel and improved method and apparatus for transmitting high speed digital data in a spread spectrum communications system. In particular, the present invention provides methods for transmitting forward link and reverse link high speed digital data. For both forward link and reverse link transmissions, the present invention describes a method for processing the data for transmission in a 1.2288 Mcps band and in a 3.6268 Mcps band. In addition, the present invention describes a method for transmitting forward link and reverse link data of both rate set 1 digital data and rate set 2 digital data. Rate set 1 digital data comprises variable rate data at rates defined as Mux Option 1 in the IS-95 standard. Rate set 2 digital data comprises variable rate data at rates defined as Mux Option 2 in the appendix to the IS-95 standard. In addition the present invention describes methods of transmitting the data for applications using packet switched technology and circuit switched technology.

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 system and method for dynamically varying traffic channel sectorization within a spread spectrum communication system is disclosed herein. In a preferred implementation, the system is operative to convey information to at least one specified user in a spread spectrum communication system and includes a first network for generating, at a predetermined chip rate, a first pseudorandom noise (PN) signal of a first predetermined PN code. The first PN signal is then combined with a first information signal in order to provide a resultant first modulation signal. The system further includes a second network for providing a second modulation signal by delaying the first modulation signal by a predetermined delay inversely related to the PN chip rate. A switching transmission network is disposed to selectively transmit the first and second modulation signals respectively to first and second coverage areas.