Abstract: A method and apparatus for effectively monitoring quality of a traffic channel in a communication, and in response, modifying transmission coding or data transmission rates, or both, improves communication quality and increases data transfers rates in digital wireless communication systems. A channel quality estimator determines and evaluates the bit error rate (BER) of a signal on a control channel and estimates the quality of the traffic channel based on the quality of the control channel signal. Accordingly, the processing and control circuitry of either a mobile station or base station adjusts the error correction applied to traffic channel transmissions. The traffic channel data transmission rate may also be modified based on the control channel signal quality.

Abstract: Techniques for Walsh space assignment are disclosed. In one aspect, a list of Walsh functions is maintained in the base station and mobile stations. A Walsh space indicator is transmitted to indicate which of the Walsh functions on the list are to be used in communication. The Walsh space indicator is updated according to the dynamically varying transmit power available or the use of Walsh functions within the base station. Methods by which a mobile station can request Walsh space information are provided. In another aspect, a Walsh space indicator channel is continually broadcast for mobile stations to detect the Walsh space indicator therefrom. In yet another aspect, the Walsh space indicator is used to initialize convolutional encoders and decoders, to provide a mechanism for mitigating against errors introduced while receiving Walsh space indicators. Various other aspects are also presented.

Abstract: High rate CDMA wireless communication is obtained by forming a set of individually gain adjusted subscriber channels. Each channel has a set of orthogonal subchannel codes having a small number of PN spreading chips per orthogonal waveform period. Preferably, the set of sub-channel codes are comprised of four Walsh codes, each orthogonal to the remaining set and four chips in duration. It is also preferred that pilot data be transmitted via a first transmit channel and power control data transmitted via a second transmit channel. The remaining two transmit channels are used for transmitting non-specified digital data including user data or signaling data, or both. One of the two non-specified transmit channels may be configured for BPSK modulation and the other for QPSK modulation.

Abstract: Methods and apparatus for synchronization of a transmitter and a receiver are based on orthogonal sequences having optimized correlation properties. The transmitter may generate signed versions of S-Hadamard sequences that are obtained by position-wise scrambling a set of Walsh-Hadamard sequences with a special sequence having complex elements of constant magnitude. The receiver estimates a time location and sequence identity of a received version of the synchronization signal.

Abstract: There is provided an apparatus and method for using QOF (Quasi-Orthogonal Function) Walsh codes when enough orthogonal Walsh codes are not available for a packet data service in a mobile communication system supporting concurrent provision of a high rate packet data service and a circuit call service. A data rate (DR1) in the case of using available orthogonal Walsh codes is first obtained. Then, a data rate (DR2) in the case of using QOF Walsh codes is obtained considering a power reduction factor due to the increase of interference involved with the use of the QOF Walsh codes. Packet data is transmitted at a higher data rate of DR1 and DR2. At the same time, information about the selected data rate and information about whether the QOF Walsh codes are used or not are transmitted.

Abstract: An apparatus and method for determining an optimum modulation scheme and code rate in a communication system using a variable transmission scheme. In a transmitter included in the communication system, an encoder encodes an encoder packet (EP) and a plurality of modulators having different modulation orders modulate sub-packets being codewords output from the encoder. A selector selects one of the modulators by comparing an MPR (Modulation order Product code Rate) being a ratio of an EP size to a number of payload modulation symbols, and comparing the MPR with a threshold.

Abstract: The invention is a CDMA decresting technology that reduces or eliminates peaks in the CDMA signal. The CDMA technology generates a correction signal in response to peaks in the CDMA signal that exceed a value. The value typically corresponds to the maximum power level of a power amplifier. The CDMA technology combines the correction signal with the CDMA signal to generate a decrested CDMA signal with reduced peaks. In some examples of the invention, the CDMA technology processes polar coordinate representations of the quadrature components of the CDMA signal to generate the correction signal. Using the invention, the power amplifier in a CDMA base station can operate at increased power levels without exceeding out-of-band signal power limitations. As a result, the base station operates more efficiently and with a greater range or capacity.

Abstract: A system and method for transmitting wideband signals via a radio communication system adapted for transmitting narrow-band signals is described. A base station is used to transmit and receive a plurality of relatively narrow-band and a plurality of relatively wideband signals. The electromagnetic spectrum available to the plurality of narrow-band signals is selectively shared with the electromagnetic spectrum available to the wideband signals by systematically separating the orthogonal codes and the carrier frequencies used for transmission. The prefixes of the orthogonal codes are preferably mutually exclusive and the carrier frequencies are preferably separated by an offset. The offset may be substantially equal to an integer multiple of the narrow-band signal's chip rate. Alternatively, the offset may be substantially equal to an odd multiple of one half the narrow-band signal's chip rate in which case every other bit of the orthogonally encoded data is inverted.

Abstract: The present invention exploits the benefits obtainable from using transmit diversity by designing the size of the interleaver matrix to avoid the case where most or all of the bits in a row are transmitted on a single antenna (110 or 112). This can be accomplished, for example, by specifying the interleaver matrix based on the type of modulation (308) used. A symbol scrambler can also be used to exploit the benefits obtainable from using transmit diversity.

Abstract: The present invention encompasses an electronic device operated in a communication system (for example 1XEV-DO, 1XEV-DV, CDMA, etc). The electronic device receiving a signal from a base station, the signal containing signaling information and data packets. The electronic device processing portion of the signal during the current frame and simultaneously storing the received signal prior to de-spreading, for further processing during the following frame. The electronic device further processing previously stored signal, during current frame.

Abstract: A digital modulation system provides enhanced multipath performance by using modified orthogonal codes with reduced autocorrelation sidelobes while maintaining the cross-correlation properties of the modified codes. For example, the modified orthogonal codes can reduce the autocorrelation level so as not to exceed one-half the length of the modified orthogonal code. In certain embodiments, an M-ary orthogonal keying (MOK) system is used which modifies orthogonal Walsh codes using a complementary code to improve the auto-correlation properties of the Walsh codes, thereby enhancing the multipath performance of the MOK system while maintaining the orthogonality and low cross-correlation characteristics of the Walsh codes.

Abstract: A handoff method in a CDMA communication system using Walsh codes and quasi-orthogonal codes. To implement a handoff, a new base station to which a call is switched notifies a serving base station of an available quasi-orthogonal code, if the new base station has no available Walsh codes. The serving base station transmits a handoff direction message to a mobile station and the mobile station communicate with the new base station using the quasi-orthogonal code included in the handoff direction message.

Abstract: A method for allocating Walsh codes by group in a CDMA (Code Division Multiple Access) cellular system is disclosed. The present invention provides a method for detecting the Walsh group having the minimum traffic group to minimize the time for allocating a call or transmitted data to an idle Walsh code, thereby, improving the performance of the system and reducing the time required to set up the call. The method includes the steps of dividing the Walsh codes into a plurality of Walsh groups; searching the plurality of Walsh groups to determine a Walsh group having the minimum traffic; identifying an idle Walsh code within the minimum traffic group; allocating the identified idle Walsh code to the call or data to be transmitted.

Abstract: A multiple channel optical fiber controller provides an optical fiber positioning control loop for each degree of freedom. Each channel represents a degree of freedom and remains independent from other channels by modulating the degrees of freedom with an orthogonal code set. The orthogonal code set is an orthogonal CDMA code set so that the optical coefficients can be distinguished from each other and degrees of freedom can be independently match filter detected. Amplitude modulation allows the state of degrees of freedom to be derived and provides the necessary feedback signal for the degree of freedom channel.

Abstract: The present invention relates to a mobile communication system, particularly relates to a power estimating apparatus of CDMA(code division multiple access) system which performs a power control of a down link or an up link in the CDMA mobile communication system and performs a power control about a CDMA signal by using an extended walsh code. A power estimating method in a CDMA system for distinguishing CDMA channels with a walsh code which is orthogonal to all CDMA channels, comprising the steps of making an extended walsh code having a new format, which is orthogonal to all CDMA channels, by extending a length(code stream) of the walsh code which is used for distinguishing the CDMA channels, according to a walsh function, and estimating a receiving power by correlating a receiving signal with the extended walsh code.

Abstract: A pilot signal enters a first MMSE receiver (201) and a second signal enters a second MMSE receiver (202). The first MMSE receiver (201) performs a channel estimate for the received pilot signal, determines a mean-square error of the pilot signal, and operates to minimize the mean-square error of the pilot estimate by constantly updating a weighting vector. An estimate of the pilot channel exits the first MMSE receiver (201). The MMSE weighting vector (206) is also fed into the second MMSE receiver (202) and is applied to the second channel. Symbol estimates (or in other embodiments, chip estimates) exit the second MMSE receiver (202) and enter channel circuitry (204), where normal channel processing occurs.

Abstract: This invention relates to a signal processing method and apparatus to enhance demodulation performance of receiving system utilizing the array antenna operating in various CDMA signal environments such as IS95 CDMA system, or IS2000 1× CDMA system, etc. The method improves the demodulation performance by applying the weight vector, which is computed in a signal processing means of a CDMA system adopting the array antenna, to the signal vectors of an Walsh demodulation outputs. The key part of the invention is in the composite procedures of finding the index D of the Walsh demodulation outputs, which corresponds to the 6-bit data transmitted from mobile terminal. More specifically, the invention provides a systematic way of applying the weight vector to each of the 64 Walsh demodulation outputs such that one index out of the 64 indices corresponding to the largest magnitude. Also the invention discloses how to compute the weight vector from received signals.

Abstract: A CDMA modem for use in a CDMA base station for communicating with a plurality of mobile stations each of which may communicate according to any of a plurality of air interface standards is hard-wired only to the extent necessary for functions common to all of the air interface standards. Remaining functions are software-configurable so as to be adaptable for any of the air interface standards.

Abstract: HF modems operate at the HF licensed frequency bands ranging from 3 to 25 MHz. This invention deals with a Quasi CDMA application of a low bit rate modem operating at a rate of 125 bps. This low rate modem has been operational for some time now, and is based on the MIL-STD 188-110A waveforms.

Abstract: High rate CDMA wireless communication is obtained by forming a set of individually gain adjusted subscriber channels. Each channel has a set of orthogonal subchannel codes having a small number of PN spreading chips per orthogonal waveform period. Preferably, the set of sub-channel codes are comprised of four Walsh codes, each orthogonal to the remaining set and four chips in duration. It is also preferred that pilot data be transmitted via a first transmit channel and power control data transmitted via a second transmit channel. The remaining two transmit channels are used for transmitting non-specified digital data including user data or signaling data, or both. One of the two non-specified transmit channels may be configured for BPSK modulation and the other for QPSK modulation.

Abstract: A system and method that codes and interleaves data onto separate channels for transmission in a wireless multicarrier system. The multicarrier wireless transmission system has an input terminal for receiving a plurality of user data bits. The system adds error-correcting bits to the user data bits. The system then arranges and stores the combination of error-correcting bits, collectively coded symbols, in a two dimensional matrix. The system arranges the coded symbols by writing them into the matrix according to columns, from left to right. The system then retrieves the symbols from the matrix according to rows, from top to bottom. The system then transmits the retrieved symbols on different carrier frequencies such that consecutive symbols are each transmitted on a different carrier frequency.

Abstract: Apparatus for a transmitter and a receiver which enhance the performance of a system coherent demodulation by utilizing non-pilot sub-channels to enhance the accuracy of estimates of amplitude and phase noise inherent in the transmission channel is described. This enhancement is accomplished by utilizing the corrected received data on a fundamental channel to enhance a pilot channel estimate, which is subsequently utilized by a dot product module in demodulating a supplementary data channel.

Abstract: Several methods and corresponding apparatus to reduce multiple access interference in code division multiple access communications systems through successive interference cancellation techniques. An estimate of reliability of cancellation of a strongest interfering signal is formed from analysis of a pilot signal associated with the strongest signal. The estimate is used to derive a weight that is multiplied by a replica of the strongest signal to provide a weighted replica. The weighted replica is subtracted from a delayed version of the received channel. As a result, interference cancellation is robustly implemented when the strongest signal replica is most likely to be accurate and is not robustly implemented when the strongest signal replica is not likely to be accurate. This avoids combining a replica of the strongest signal with the received channel when the replica is more likely to contribute additional interference rather than reduce it.

Abstract: A digital modulation system provides enhanced multipath performance by using modified orthogonal codes with reduced autocorrelation sidelobes while maintaining the cross-correlation properties of the modified codes. For example, the modified orthogonal codes can reduce the autocorrelation level so as not to exceed one-half the length of the modified orthogonal code. In certain embodiments, an M-ary orthogonal keying (MOK) system is used which modifies orthogonal Walsh codes using a complementary code to improve the auto-correlation properties of the Walsh codes, thereby enhancing the multipath performance of the MOK system while maintaining the orthogonality and low cross-correlation characteristics of the Walsh codes.

Abstract: A method for assigning orthogonal codes used for a first system and a second system in a CDMA system including channels of the first system for spreading a pilot signal, a sync signal, a paging signal and a traffic signal with a first set of orthogonal codes corresponding to orthogonal code numbers in different rows from a set of orthogonal codes arranged in a matrix of m rows and m columns, and channels of the second system for spreading a second set of orthogonal codes corresponding to orthogonal code numbers different from said orthogonal code numbers for the first set of orthogonal codes. The orthogonal codes for the second system are transmitted at a data rate higher than a data rate of the first system.

Abstract: A novel and improved method and apparatus for high rate CDMA wireless communication is described. A set of individually gain adjusted subscriber channels are formed via the use of a set of orthogonal subchannel codes. The set of sub-channel codes are comprised of four Walsh codes. The pilot data and control data are combined onto one channel. The remaining two transmit channels are used for transmitting non-specified digital data including user data or signaling data, or both.

Abstract: A complex spreading and/or scrambling code sequence generation system uses a first complex code sequence having at least two components and a second complex code sequence having at least two components. The components of the first complex code sequence are respectively mixed with the corresponding components of the second complex code sequence to generate the complex scrambling code sequence. In doing so, an offset between the components of the complex scrambling code sequence is achieved for the same and/or different users. The complex scrambling code sequence can be used for spreading, scrambling, de-spreading or descrambling an information signal.

Abstract: The present invention provides a transmission controller and method for processing data items to be transmitted over a wireless link connecting a central terminal and a subscriber terminal of a wireless telecommunications system, a single frequency channel being employed for transmitting data items pertaining to a plurality of wireless links. The transmission controller comprises an orthogonal code generator for providing an orthogonal code from a set of ‘m’ orthogonal codes used to create ‘m’ orthogonal channels within the single frequency channel, and a first encoder for combining a data item to be transmitted on the single frequency channel with said orthogonal code from the orthogonal code generator, the orthogonal code determining the orthogonal channel over which the data item is transmitted, whereby data items pertaining to different wireless links may be transmitted simultaneously within different orthogonal channels of said single frequency channel.

Abstract: A device for generating quasi-orthogonal codes which allow the minimum interference with orthogonal codes in a mobile communication system using the orthogonal codes. The device includes a first spreader for spreading at least one input signal with quasi-orthogonal codes, a second spreader for spreading another input signal with Walsh codes, and a PN (Pseudo-Noise) spreader for complex-spreading output signals of the first and second spreaders with PN sequences. The quasi-orthogonal codes are characterized in that a partial correlation value with the Walsh codes does not exceed a lowest partial correlation limit value.

Abstract: Methods and apparatuses for transmitting and receiving enhance the performance of a system utilizing interleaving and transmit diversity by reordering the sequence of symbols transmitted along the different transmission channels. This enhancement is accomplished by providing different shuffling functions in conjunction with the interleavers and deinterleavers used with different transmission channels, which decreases the probability of loss of sequential symbols when transmission channels or antennas become correlated.

Abstract: A method and apparatus for providing orthogonal spot beams (14a, 14b), sectors (16a, 16b), and picocells (18), by using orthogonal auxiliary pilots and different Walsh traffic channels in adjacent areas. According to the IS-95 standard, the pilot signal is covered with the 64-chip Walsh sequence zero. Designating the 64-chip all zeros Walsh sequence as P and the 64-chip all one sequence as M, additional pilot signals are provided in the present invention by concatenating the P and the M sequences. Thus, for two pilot signals, pilot Walsh sequences of PP and PM can be used. For four pilot signals, pilot Walsh sequences of PPPP, PMPM, PPMM, and PMMP can be used. In general, the required number of pilot Walsh sequences can be generated by substituting each bit in an K-bit Walsh sequence with the 64-chip all zeros P or all ones M sequence, depending on the value of that bit.

Abstract: Apparatuses for a transmitter and a receiver which enhance the performance of a system utilizing interleaving and transmit diversity by reordering the sequence of symbols transmitted along the different transmission channels. This enhancement is accomplished by providing different shuffling functions in conjunction with the interleavers and deinterleavers used with different transmission channels, which decreases the probability of loss of sequential symbols when transmission channels or antennas become correlated.

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: An apparatus for reducing power amplifier headroom in a wireless transmission system comprises an orthogonal modulation circuit and a phase rotation circuit coupled to the orthogonal modulation circuit. The orthogonal modulation circuit utilizes a Walsh code for modulating an in-phase signal and a quadrature signal. The orthogonal modulation circuit has an in-phase output and a quadrature output. The phase rotation circuit rotates phase of the in-phase signal and the quadrature signal, producing a phase rotated in-phase signal and a phase rotated quadrature signal. Multiple Walsh code defined channels are associated with a particular wireless user.

Abstract: A message, e.g., a control message, a short message, a voice message or a data message, is transmitted on at least one of a first communications channel having a first redundancy level or a second communications channel having a second, higher redundancy level. A radio communications signal is received on one of the first communications channel and the second communications channel. The received radio communications signal is demodulated to recover the message using a first demodulation scheme if the radio communications signal is received on the first communications channel and using a second demodulation scheme if the radio communications signal is received on the second communications channel. According to an aspect of the invention, the received radio communications signal is coherently demodulated if the radio communications signal is received over the first communications channel and non-coherently demodulated if the radio communications signal is received over the second communications channel.

Abstract: A communication circuit is designed with a processing circuit (11) coupled to receive a plurality of first control signals (40-45) and a second control signal (46) from a source external to the communication circuit during a predetermined time (49). The plurality of first control signals are equally spaced apart in time. The second control signal is proximate one of the first control signals (40). The processing circuit produces a power control signal in response to at least two of the plurality of first control signals. A serial circuit is coupled to receive the power control signal. The serial circuit produces the plurality of third control signals and the power control signal.

Abstract: An integrated search processor used in a modem for a spread spectrum communications system buffers receive samples and utilizes a time sliced transform processor operating on successive offsets from the buffer. The search processor autonomously steps through a search as configured by a microprocessor specified search parameter set, which can include the group of antennas to search over, the starting offset and width of the search window to search over, and the number of Walsh symbols to accumulate results at each offset. The search processor calculates the correlation energy at each offset, and presents a summary report of the best paths found in the search to use for demodulation element reassignment. This reduces the searching process related workload of the microprocessor and also reduces the modem costs by allowing a complete channel element modem circuit to be produced in a single IC.

Abstract: An adaptive receiver for base stations of CDMA mobile wireless systems corresponding to the IS-95 Standard. The receiver is designed as an incoherent rake receiver and includes an antenna array. The receiver is capable of analyzing a plurality of components of the same signal transmitted by a mobile station arriving at the antenna array via different propagation paths and from different directions with a time offset. To form virtual antenna directivity patterns for individual rake processing paths, which are adjusted to the directions of incidence of the signal paths to be analyzed, direction signature vectors are calculated and made available to the processing paths together with a signal propagation time that is required for synchronizing the signal components. The direction signature vectors are calculated iteratively from the antenna correlation matrices formed recursively for all possible signal delay times from pulse responses of the antenna arrays.

Abstract: A base station system of a multicarrier CDMA and a data transmission method and a mobile communication system using the same are disclosed.

Abstract: In a wireless communications system, information is communicated over one of a first communications channel having a first redundancy level or a second communications channel having a second redundancy level based on a determination of communications quality for at least one of the channels. In embodiments of the present invention, communications occur over a first channel, e.g., a “standard” channel until a measure of communications quality for that channel, such as bit error rate or frame error rate, meets a predetermined criterion. When the communications quality meets the predetermined criterion, communications shifts to a “robust” high-penetration channel that utilizes substantially the same amount of spectral resource as the first channel but provides significantly increased redundancy. In other embodiments, a terminal, e.g.

Abstract: A method and apparatus for assigning Walsh codes in a direct sequence spread spectrum (DS-SS) telecommunications system. Walsh code sets are each generated from a different Walsh code Cx of length N. Each of the code sets is mutually disjoint to one another, i.e., each is generated from a different Walsh code Cx of length N, and each Walsh code Cx is from the same Walsh code matrix W. Each code set may be used to support a set of parallel CDMA channels. Because the codes of each Walsh code set are generated from the same Cx, a number of least significant bits from the code indexes of the codes in the set are equal and identical to the code index for the Cx used to generate the set. Assignment messages may be reduced in length by preassigning the code index of Cx to selected channels and then transmitting only the additional information necessary to specify the index of the assigned codes from the general code set generated from the Cx.

Abstract: The system and method of the present invention uses a plurality of carriers by assigning user terminals to the plurality of carriers so that a minimum grade of service is met and so that throughput is maximized. Each serviced user terminal reports the channel quality of each of a plurality of carriers to a servicing base station(s). The reported channel qualities are then converted to maximum supported data rates for each of the user terminals and each of the carriers. These data rates are then used to allocate data service levels and data rates for each of the user terminals so that a minimum grade of service is met for each of the user terminals. Forward link transmissions, e.g., frames/data packets carried on forward channels (F-CHs), are then constructed and transmitted to meet the allocations.

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: An interleaver memory access apparatus of a CDMA system includes: an interleaver memory for storing code symbols to be transmitted; a shift register unit for simultaneously receiving 18 bit code symbols from the interleaver memory and outputting it by 6 code symbols; an index decoding unit for decoding the 6 code symbols outputted from the shift register unit and generates a Walsh index; an address generator and control logic for controlling the access operation of the interleaver memory and the input and output operation of the shift register unit and the index coding unit; and an orthogonal modulator for outputting 64 Walsh codes on the basis of the Walsh index outputted from the index decoding unit. Since the interleaver memory performs reading operation by only using the row address, a simple addressing is implemented for the memory access, so that the performance of the overall CDMA system as well as the data access speed can be enhanced.

Abstract: A method and apparatus for providing orthogonal spot beams, sectors, and picocells. The transmissions can be made orthogonally by using orthogonal auxiliary pilots and different Walsh traffic channels in adjacent areas. In accordance with the IS-95 standard, the pilot signal is covered with the 64-chip Walsh sequence zero. The 64-chip all zeros Walsh sequence can be designated as P and the 64-chip all one sequence can be designated as M. In the present invention, additional pilot signals can be provided by concatenating 64-chip all zeros P and all ones M sequences. Thus, for two pilot signals, pilot Walsh sequences of PP and PM can be used. For four pilot signals, pilot Walsh sequences of PPPP, PMPM, PPMM, and PMMP can be used. The present invention can be extended such that any required number of pilot Walsh sequences can be generated by substituting each bit in an K-bit Walsh sequence with the 64-chip all zeros P or all ones M sequence depending on the value of that bit.

Abstract: A CDMA communication system supports underlay transmissions and direct spread overlay transmissions such that the overlay transmissions are at least partially orthogonal to underlay transmissions. A base station supports both the underlay transmissions and the overlay transmissions and includes an interface to a mobile switching center, an underlay unit, an overlay unit and at least one radio frequency (RF) unit. The interface receives communications intended for a plurality of mobile stations serviced by the base station. These communications include underlay communications intended for mobile stations (MSs) supporting underlay transmissions and overlay communications intended for MSs supporting overlay transmissions. The underlay unit receives the underlay portion of the communications and produces underlay transmissions. The overlay unit receives the overlay portion of the communications and produces overlay transmissions.

Abstract: The invention is a method and system for reducing the dynamic range of a signal input to a power amplifier in a CDMA forward-link transmission system. This is achieved by introducing a controllable amount of code-domain distortion to the data prior to spreading by Walsh codes. The amount of distortion is calculated by creating a data vector, applying a transform to the data vector to obtain a sequence, distorting the result to obtain a distorted sequence, applying an inverse transform to the distorted sequence to obtain a distorted data vector and comparing the distorted data vector to the original data, thereby to obtain the amount of code-domain distortion to be added to the data. The resultant, “corrected” spread-spectrum waveform can be controlled to the extent that it is guaranteed never to exceed a prescribed voltage range.

Abstract: Methods for switching a mobile between operation in an mobile satellite system mode and a terrestrial wireless mode. When operating in the terrestrial wireless mode, the mobile terminal will initiate an attempt to switch into the MSS mode when it nears the boundary of the coverage area for a terrestrial wireless system to which it is registered. Conversely, a mobile terminal operating in the MSS mode will regularly attempt to switch into the terrestrial wireless mode. For both, a switch between modes is contingent on the mobile terminal identifying a suitable system for registration therewith upon completing the switch between modes. The criteria for identifying a suitable system for selection purposes include the following: (1) the selected system is available, i.e., the mobile terminal is physically located within a coverage area for the selected system; (2) the mobile terminal is compatible with the selected system; and (3) the selected system is willing to accept the mobile terminal.

Abstract: To simultaneously transmit data related to two channels using code division data related to a first channel (DTCH) are spread parallely using a first spreading code (CI) and a second spreading code (CQ), data related to a second channel (PCCH) are spread parallely using a first spreading code (CI) and a second spreading code (CQ), the power level of a signal representing said data related to the second channel (PCCH) after the spreading is changed (G) with respect to the power level of a signal representing the data related to the first channel (DTCH) after the spreading, and a transmission is compiled from spread data related to the first channel and spread data related to the second channel the power level of which has been changed.

Abstract: In this patent, we present MultiCode Direct Sequence Spread Spectrum (MC-DSSS) which is a modulation scheme that assigns up to N DSSS codes to an individual user where N is the number of chips per DSSS code. When viewed as DSSS, MC-DSSS requires up to N correlators (or equivalently up to N Matched Filters) at the receiver with a complexity of the order of N2 operations. In addition, a non ideal communication channel can cause InterCode Interference (ICI), i.e., interference between the N DSSS codes. In this patent, we introduce new DSSS codes, which we refer to as the “MC” codes. Such codes allow the information in a MC-DSSS signal to be decoded in a sequence of low complexity parallel operations which reduce the ICI. In addition to low complexity decoding and reduced ICI.