Abstract: Parallel interference cancellers are connected in successive stages. In each canceller, multiple signal paths are provided for interference replica estimators to receive multiple CDMA channels. A spread code is generated for each signal path for dispreading the path components of the channel. In each signal path, the despread components are RAKE combined and a symbol replica is detected therefrom either by detecting or estimating the type of modulation. The detected symbol replicas are re-modulated and then re-spread to produce interference replicas. In each stage, the interference replicas are summed and subtracted from a delayed CDMA signal and then summed with the interference replicas of the same stage. Output signals from the final stage are despread and symbol replicas are recovered therefrom. For each signal path, a spread code is detected from a control channel and compared to the generated spread code.

Abstract: A spread spectrum noise shaper uses a modulation technique to achieve a greater signal-to-noise or signal-to-interference ratio (SNR or SIR). The technique doubles the system SIR, in principle. This doubling yields a doubling in system capacity. SNR is increased by receiving the spread spectrum signal in the presence of less noise near the edge of the spread spectrum bandwidth. The technique requires only small additions to a conventional spread spectrum system, in the form of an extra modulator at the transmitter, and an extra demodulator and filter at the receiver.

Abstract: In the method of packet transmission, data packet fragments received from a first mobile station are sent to a second mobile station without assembling and re-fragmenting the received data packet fragments if the first and second mobile stations are in a same cell.

Abstract: A spread spectrum based multichannel modulation Ultra-Wideband (UWB) communication transceiver for indoor wireless operations is presented according to some embodiments. The spread spectrum based multichannels are orthogonal to each other and allow for an operation in parallel. The UWB communication transceiver can also avoid interference with WLAN 802.11a devices in the same environment. In addition, the UWB communication transceiver of the present invention can transmit and receive the scalability chip data rates from 650 Mcps to 7.15 Gcps.

Abstract: Method and apparatuses for broadcasting and receiving a programme are presented. A programme is broadcast from a broadcasting system. Broadcast programme-associated data is transferred from a server to a cellular radio network. The broadcast programme-associated data is transmitted from a base station of the cellular radio network at a specific frequency defined for the cellular radio network in such a manner that the transmission of the broadcast programme-associated data is synchronized with the broadcasting of the programme. The programme and the broadcast programme-associated data is received with a subscriber terminal of the cellular radio network in such a manner that a programme receiver of the subscriber terminal receives from the broadcasting path of the broadcasting system the programme and a cellular radio network transceiver of the subscriber terminal receives the broadcast programme-associated data at a specific frequency.

Abstract: In a transmission method of the present invention, when transmitting an information bit from a transmitter to a receiver, an encoder of the transmitter firstly inputs and encodes the information bit, and a modulator then modulates the encoded information bit to create a modulation symbol. A spreader spreads the obtained modulation symbol using a rotation orthogonal code having a rotation angle that is appropriate to a combination of the modulation method and the coding rate, and transmits it to a transmission path. The receiver performs a reverse operation of the transmitter, and decodes the information bit. In QPSK modulation where the coding rate of an error-correction code is ½, when a rotation angle that obtains a same signal point as OFDM is 0°, spreading is performed using a rotation orthogonal code having a rotation angle of between 17° and 45°, or between ?17° and ?45°, thereby reducing bit error and enabling highly-reliable communication to be achieved.

Abstract: Systems and methods for bidirectional communication are provided. In one embodiment, a method for aligning communications from a plurality of remote units in a multipoint-to-point orthogonal frequency division multiplexed (OFDM) communications comprises sending a first signal from a host unit to a first remote unit; receiving a second signal transmitted from the first remote unit in response to the first signal; generating at least one timing adjustment signal based at least in part on a round trip delay between the sending of the first signal and the receiving of the second signal; transmitting the timing adjustment signal to the first remote unit; wherein the timing adjustment signal instructs the first remote unit to delay OFDM transmission of data to improve alignment of multiframes at the host unit when communications are received at the host unit from the plurality of remote units.

Abstract: An apparatus with a first information decoder (103) and an information encoder (104) operates in at least one of a lossless and a lossy encoding modes to re-encode original information decoded by the first information decoder (103). A transmitter (105) is coupled to the information encoder (104) and to at least one receiver (112) which is coupled to a second information decoder (113). The second information decoder (113) operates in the at least one of the lossless and the lossy decoding modes to recover information substantially representing content associated with the original information.

Abstract: The present invention concerns a method of mapping chips of a spread out symbol to sub-channels of a group of sub-channels of a Multi-Carrier transmission channel of a Multi-Carrier transmission network, the spread out symbol being formed by multiplying a data item to be transmitted by elements of a spreading sequence, the mapped chips being further modulated using an orthogonal frequency division multiplexing modulation, each sub-channel of the Multi-Carrier transmission channel being defined by a carrier frequency of the Multi-Carrier transmission channel and a time slot wherein an orthogonal frequency division multiplexing symbol is transmitted, wherein the chips are ordered in a predetermined order.

Abstract: A system and method for generating a clock signal having spread spectrum modulation. The method involves generating a clock signal by generating edge positions for edges of the clock signal from a digital representation of a timing for each edge to impart spread spectrum modulation to the clock signal. A programmable modulator is provided that generates digital values representing edge positions for edges of a clock signal based on at least one of a time-varying period value and a time-varying duty-cycle value. The programmable modulator may comprise a first circuit, called a period modulation circuit, that generates a time-varying digital period value, and a second circuit, called a duty-cycle modulation circuit, that generates a time-varying digital duty-cycle value. The time-varying period values and time-varying duty cycle values are processed to produce a digital edge position value that specifies an edge position for a clock signal.

Abstract: Systems and methods for a cumulant-based discriminator for global navigation satellite system code alignment are provided. In one embodiment, a method for determining a misalignment between a GNSS coarse acquisition code signal and a replica code is provided. The method comprises producing code samples of a spread spectrum signal received from a satellite; multiplying the code samples by a current value of a replica code; and calculating a set of multiple-order cumulants based on the code samples multiplied by the current value of the replica code.

Abstract: Agile Radio Frequency (RF) band selectable systems and circuits process and provide selection of baseband filtered Orthogonal Frequency Division Multiplexed (OFDM) modulated signals, of spread spectrum (SS) modulated signals and of baseband in-phase (I) and quadrature-phase (Q) shaped and or filtered baseband cross-correlated and modulated signals. A selector selects one or more of the filtered and or shaped RF modulated signals and provides the selected signal to the transmission medium. RF tunable (RF agile) circuits receive a first baseband filtered and modulated signal at a first bit rate and provide a first RF modulated signal in a first specified RF band and receive a second baseband waveform shaped and modulated signal at a second bit rate and provide waveform shaped and modulated RF signal in a second specified RF band, with the second specified RF band having a different specified RF band than the first specified RF band and the first bit rate being different than the second bit rate.

Abstract: A transmitter for ultra wideband communications includes a spread modulator for spreading input data to a wideband signal having a form in which a plurality of carriers are constantly transmitted and a amplifier for amplifying the spread signal obtained from the spread modulator. The amplified signal obtained from the amplifier is transmitted as a baseband signal by one of a wired and wireless transmission.

Abstract: Techniques and systems for estimating the spreading factor of data in a channel in a spread spectrum radio communication system is described. An illustrative method includes communication between a base station and a mobile station that takes place over a multirate data channel having a corresponding control channel. The control channel is transmitted in parallel with the data channel and is decoded to extract control information in order to decode the data channel. An illustrative method and system for estimating the spreading factor of data in a channel in a spread spectrum radio communication system includes a transmitter and a receiver, wherein the transmitter transmits a data unit at one of a plurality of spreading factors over a data channel and transmits in parallel over a control channel a control unit including information for decoding the data unit.

Abstract: An apparatus and associated methods to aid in system identification in a heterogeneous communication environment is generally described herein.

Abstract: An apparatus for transmitting/receiving a signal in a communication system is provided. A Mobile Station (MS) spreads a transmission signal to generate a spreading signal, receives, from a Base Station (BS), information on a second spreading signal transmission region, extended from a first spreading signal transmission region, and maps the generated spreading signal to a subcarrier in the second spreading signal transmission region. A Base Station (BS) transmits information on a second spreading signal transmission region extended from a first spreading signal transmission region, for reception of a spreading signal, receives a spreading signal mapped to subcarriers over the second spreading signal transmission region, from an Mobile Station (MS), detects a spreading signal from the spread signal mapped to the subcarriers, and despreads the detected spreading signal to restore a transmission signal.

Abstract: Transmit power adaptation for DS/CDMA systems is disclosed for a CDMA system that utilizes a successive interference cancellation receiver on fading channels. The transmission power is adapted in response to channel variations to achieve an arbitrary power profile for received signal powers at the system base station. That is, the received signal powers are distributed with some factor xi's given as: SRi=SR(1)xi, (i=2, 3, . . . , K and x1=1) where K is the number of users and SR(i) is the received signal power of the user having the ith strength, and wherein user strengths are ranked in the order of estimated channel gains. The factor xi gives a measure of the disparity between the received power levels. The channel is estimated at both the transmitter and receiver. In one embodiment, the factors, xi, for distributing the signal powers are selected such that the average BER for each user is minimized.

Abstract: A method of tuning a station is disclosed, wherein a first pilot signal is applied on a circuit of the station and the resulting output power of the signal circuit is subsequently detected. A second pilot signal is then applied to the circuit and the resulting output power of the circuit is detected. The offset of the circuit is then tuned based on information of the resulting output power detected for the first and second signals. A station that is adapted to implement the method may be tuned by the manufacturer thereof or later after having already been taken into use. The tuning may occur automatically as response to a predefined event.

Abstract: A transmitter used in a wireless communication system based on an orthogonal frequency division multiplexing (OFDM) scheme includes a determination unit that determines a spreading factor and an amplitude for a control channel based on at least one of signal quality information and interference information in data transmission. The transmitter also includes a multiplexing unit that multiplexes a data channel with the control channel having been code-spread based on the spreading factor and the amplitude. A modulator then modulates the multiplexed signal in the OFDM scheme for transmission as OFDM symbols.

Abstract: A multi-carrier communication system such as an OFDM or DMT system has nodes which are allowed to dynamically change their receive and transmit symbol rates, and the number of carriers within their signals. Changing of the symbol rate is done by changing the clocking frequency of the nodes' iFFT and FFT processors, as well as their serializers and deserializers. The nodes have several ways of dynamically changing the number of carriers used. The selection of symbol rate and number of carriers can be optimized for a given channel based on explicit channel measurements, a priori knowledge of the channel, or past experience. Provision is made for accommodating legacy nodes that may have constraints in symbol rate or the number of carriers they can support.

Abstract: The invention relates to a device for exchanging digital data between several sources and at least one hub in a CDMA system, characterized in that it comprises a number n of digital transmission/reception circuits (1) installed in parallel, each circuit (1) comprising a transmitter (2i) comprising means of generating an integer number Nc of codes that will be used for spectral spreading of data to be transmitted and a receiver (4i) comprising means (46, 48) of detecting the access of new sources to the CDMA system transmission channel and means (49) of generating synchronization signals and power control signals corresponding to each detected new source.

Abstract: The ultra wide band communication system of the present invention includes a transmitter (station) and a receiver (station). The transmitter and the receiver employ spreading code comprised of code groups, which respectively comprise varied, auto-correlated codes. Consecutive information bits are spread and de-spread with differing code and the code groups are correlated with each other (e.g., orthogonal) so as to reduce channel impulse response estimation noise. At the receiver, subsequent channel estimates can be added or averaged with an initial channel estimate so as to reduce the channel impulse response estimation noise and thereby provide a relatively more accurate channel response.

Abstract: A system and method for synchronizing and selectively addressing multiple receivers in a wireless communication system includes a spread spectrum transmitter and one or more spread spectrum receivers. The transmitter transmits a signal having an observable parameter which is pseudo-randomly varied. The receiver measures the relative times between recurrences of a selected value of the observable parameter being pseudo-randomly varied, and determines an initial state of the transmitter based upon the measured relative times. The receiver then synchronizes itself to the estimated current state of the transmitter using the determined initial state as a starting reference. In a frequency hopping embodiment, the spread spectrum transmitter comprises a feedback shift register, and transmits a sequence of pseudo-randomly hopped frequencies determined by the shift register.

Abstract: In multicarrier transmission for multiplying transmit data individually by each code constituting orthogonal codes and transmitting each result of multiplication by a prescribed subcarrier, a plurality of different subcarriers are assigned exclusively to each user and each user performs multicarrier transmission of the transmit data by the subcarriers assigned. Further, a base station assigns a plurality of different subcarriers to each user exclusively, applies beam-forming processing on a per-user basis and performs multicarrier transmission of transmit data to each user by the subcarriers assigned.

Abstract: There is provided a code acquisition device and method using a two-step search process in a DS-CDMA UWB modem. The device includes: an I/Q channel symbol generating unit for, generating a plurality (i) of nth I/Q channel symbols in a first search process and generating a plurality of nth I/Q channel symbols in a second search process; a spread code selecting unit for receiving the plurality of nth I/Q channel symbols in the first search process; an NNC2NS tap I/Q channel symbol matched filter unit for, in the second search process, receiving the plurality (i) of nth I/Q channel symbols; a switching unit for changing to a closed state of the second search process; and a super frame and symbol boundary time deciding unit for deciding a super frame time and a symbol boundary time.

Abstract: A method encodes a sequence of blocks of input bits to be transmitted over a wireless channel. Each block of input bits is converted to a codeword, and each codeword is mapped to multiple sub-blocks of complex numbers. Each sub-block is multiplied by a disambiguating spreading transform to obtain a sub-block of transformed symbols, which can be modulated and transmitted to a receiver, where each received block is demodulated to a block of complex numbers, which are partitioned into sub-blocks. The sub-block of complex numbers are converted to a set of likelihood ratios that correspond to decoded codewords. The input bits can be decoded unambiguously even if only one of the blocks of symbols corresponding to the block of input bits is received correctly.

Abstract: Embodiments of the present invention are directed to acoustic data transmission using a spreading code. A system for acoustic data transmission includes an ingestible capsule and an acoustic receiver. The ingestible capsule includes a modulator, a spreader, and an acoustic transmitter. The modulator modulates data according to a modulation scheme. The spreader spreads the modulated data according to a spreading code. The acoustic transmitter acoustically transmits the modulated and spread data through a body of an animal. The acoustic receiver includes an acoustic transducer a de-spreader and a demodulator. The acoustic transducer receives the acoustically transmitted signal and forms an electrical signal therefrom. The de-spreader de-spreads the received signal in accordance with the spreading code.

Abstract: A GPS communication system including a server and a client, each including a GPS receiver, for reducing the code phase search space of the GPS receiver of the client. The communication system includes a transmitter for transmitting timing information from the server to the client to help the client locate a first satellite, and a receiver for using timing differences between the satellites to synchronize and locate other satellites. The code phase search space is reduced by reducing the number of phase hypotheses that must be calculated to establish communication between the server and the client.

Abstract: The present invention provides a method and apparatus for multiplexing code division and frequency division transmissions. One embodiment of the method includes accessing at least one first symbol and at least one second symbol, encoding the at least one first symbol according to a frequency division protocol, and encoding the at least one second symbol using a coding sequence having a cyclic correlation property. The method also includes transmitting a radiofrequency signal indicative of the at least one encoded first symbol and the at least one encoded second symbol.

Abstract: The present invention discloses a method for pilot channel tracking based on multipath channel barycenter tracking loop, comprises steps of evaluating multipath fading channel parameters, calculating the barycenter of a multipath energy window, and loop filtering and adjusting the phase of spread spectrum sequence codes. The method of the invention does not need to individually track each delay path, thereby improving the tracking performance and timing recovery stability of a spread spectrum receiver. Only a multipath channel evaluator and a multipath energy window barycenter calculating means are used to track PN signals from a plurality of signal sources, thereby reducing hardware. Thus, a novelty coherent spread spectrum receiver can be constituted by cooperating with other parts.

Abstract: The present invention relates to positioning of a mobile signal transmitter (MT), wherein a respective distance (DMT-100a-DMT-100d) between the transmitter (MT) and each of a plurality of sensors (100a-100d) is determined based on a direct sequence spread spectrum signal (SMT). A transmitter delay of the signal (SMT) is estimated with high accuracy by, in each sensor (100a-100d), cross-correlating an over-sampled representation of the signal (SMT) with an appropriate local spreading sequence (SPP), which contains poly-phased symbol values being different from a set of symbols in the direct sequence used to spread the transmitted signal (SMT). The local spreading sequence (SPP) has a nominal chip period, which is equivalent to the chip period of the over-sampled representation of the signal (SMT).

Abstract: The invention provides a signal processing semiconductor integrated circuit of the direct conversion system, which includes a dummy amplifier having the same circuit configuration as a low noise amplifier being the first stage amplifier, in which the DC offset calibrations on the subsequent stage amplifiers are carried out during shifting into the reception mode in a state that the low noise amplifier is deactivated and the dummy amplifier is activated. Thereby, the invention achieves to suppress generation of the DC offsets resulting from the leakage noises of the local oscillator during shifting into the reception mode, and to enhance the reception sensitivity.

Abstract: An improvement to a code-division-multiple-access (CDMA) system employing spread-spectrum modulation, with the CDMA system having a base station (BS) and a plurality of remote stations. The base station has a BS-spread-spectrum transmitter and a BS-spread-spectrum receiver. A remote station has an RS-spread-spectrum transmitter and an RS-spread-spectrum receiver. The BS transmitter transmits a broadcast common-synchronization channel, which includes a frame-timing signal. The broadcast common-synchronization channel has a common chip-sequence signal, which is common to the plurality of remote stations. In response to the RS-spread-spectrum receiver receiving the broadcast common-synchronization channel, and determining frame timing from the frame-timing signal, an RS-spread-spectrum transmitter transmits an access-burst signal. The access-burst signal includes a collision-detection portion.

Abstract: An improved transmission method for high-rate digital communication on unshielded twisted copper pairs for Very-High Speed Digital Subscriber Loop (VDSL) modems. The new modulation scheme is a Multi Code Multi Carrier Code Division Multiple Access, hereafter named MC2 CDMA. The system takes advantage from both the CDMA modulation and the Multi-Carrier transmission and, in addition, the channel throughput is increased adopting a multi-code approach. The novel scheme encompasses transmitter, channel and receiver loading.

Abstract: A digital broadcast receiving apparatus for receiving a broadcast signal generated by combining sub signals modulated using a random sequence generated based on an initial value set in accordance with a frequency of a broadcast channel by a signal transmission control use signal and a main signal generated based on information source data and reproducing the information source data contained in the received broadcast signal.

Abstract: A system and method is provided for transmitting data signals and additional information signals having partially overlapping frequency bands simultaneously within a wire based communication system over the same wired medium using a spread spectrum technique for modulating the additional information signals.

Abstract: On the basis of control information for CQI transmission of which a base station notifies a mobile station, the mobile station transmits CQI information for each sub-frame in a case of best effort type service or transmits the base station the CQI information at one time for every four sub-frames in a case of rate preservation type service.

Abstract: A code division multiple access (CDMA) mobile communication system with improvements to permit stable reception with a minimum of bit error. The system includes a base station and a mobile station for communicating with the base station. The mobile station includes an oscillator, a radio frequency demodulator for demodulating a radio frequency band signal received from the base station by use of a first signal from the oscillator, a radio frequency modulator for modulating a second signal to be transmitted by use of the first signal from the oscillator, and an antenna for receiving the radio frequency band signal transmitted from the base station, and for transmitting the modulated second signal to the base station. An oscillation frequency of the oscillator is controlled by use of a change of phase shift detected using the demodulated radio frequency band signal received from the base station.

Abstract: A spreading code generating apparatus carries out M-sequence multiplication and zero value addition of generated orthogonal codes to obtain channel identification codes, and then carries out inverse Fourier transform of the channel identification codes to generate spreading codes and inverse spreading codes. A transmitting apparatus and a receiving apparatus store the spreading codes and the inverse spreading codes generated by the spreading code generating apparatus, respectively, and use a single code respectively selected from the stored codes to carry out spread spectrum communication. With the use of the spreading codes for spreading, the input signal is spread over a wide frequency band with uniform power on the frequency axis. Thus, transmission characteristics are improved, and multiplexing capacity is increased.

Abstract: A method and an apparatus for transmitting data using multi-MOK modulation/demodulation transmission process corresponding to transmitter and receiver are disclosed. At transmission, the data to be transmitted is divided into N data blocks. The N blocks are processed in parallel in N M-ary orthogonal keying (MOK) modulation channels, each modulation using a group of spread codes, each channel emitting a signal, all these signals (S) are transmitted in series. At reception, the signal received (R) is processed in N MOK demodulation channels and the blocks obtained are grouped together in series.

Abstract: A communication device for W-CDMA signal transmission and reception includes a W-CDMA transmitter having at least one of a RAM and registers, a W-CDMA receiver having at least one of a RAM and registers, and a signal acquisition circuit. The communication device is software reconfigurable and further includes a digital circuit for phase unbalance precompensation in the W-CDMA transmitter. The digital circuit includes an input register holding a compensation angle and a section performing arithmetic calculations to acquire a change of an I, Q angle by the compensation angle. A method of operating a W-CDMA communication device includes the acts of configuring the device for a specific use, and performing at least one of transmitting, receiving and acquiring waveform signals. The configuring is preferably done by a processor.

Abstract: A method and apparatus are disclosed for modulating a communication signal in a CDMA environment using orthogonal N by N Hadamard spread spectrum codes. Orthogonal spreading codes are used that have lengths that are not a power-of 2 to provide additional channel variability for various multimedia applications and increase the flexibility of the number of channels/bandwidth relationship. The Hadamard codes are multiples of 4 (4n) and demonstrate a good cross-correlation property, making them very useful in the flexible design of CDMA systems. A transmitter encodes each of N data streams (N not being a power of 2), to be transmitted using a 4n codeword, Ni. The received signal is passed through a filter matched to the characteristics of the appropriate codeword, Ni, and PN spreading sequence.

Abstract: A hierarchical WRAN includes a relay station (RS) possessing dual roles. A RS acts from the perspective of a base station (BS) as a consumer premise equipment (CPE) terminal just as any other first tier CPE terminal. Simultaneously, the RS, from the perspective of other second tier CPEs, acts as a BS providing all of the functional capabilities of a BS. The RS includes dual medium access control (MAC) functions in which a first MAC function serves to interface the RS with the BS while the second MAC function serves to interface the RS with the at least one CPE terminal. The RS further includes a convergence layer that maps, at the RS, the first MAC to the second MAC. The dual MAC capability of the RS enables the RS to pipeline frame transmission in both single and multi-channel operations.

Abstract: In an amplifier system that linearizes an amplifier by pre-distorting the input signal prior to amplification, a baseband pre-distortion processor processes the input signal in a digital baseband domain to generate one or more pre-distortion parameters based on the power of the digital baseband input signal. The digital baseband signal is up-converted and D/A-converted into a non-baseband (e.g., IF or RF) signal which is then pre-distorted, e.g., using a phase/gain adjuster or a vector modulator. By generating the pre-distortion parameters at baseband, while pre-distorting the input signal at non-baseband, the amplifier system avoids the cost and inaccuracies associated with analog signal delay and RF power detection of prior-art “all-RF” pre-distortion implementations, while avoiding the wider-bandwidth filtering of prior-art “all-baseband” pre-distortion implementations.

Abstract: A method and system is disclosed for generating and detecting variable sequence PN codes. PN-Code sequence changes based on varying interceptor threat levels are generated at a rate fast enough to avoid exploitation while maintaining a reasonable correlation search window. The PN code sequence is phase shifted by N-chips based on the severity of the threat environment. A synchronized receiver demodulates the PN encoded signal by correlating over every possible phase of the PN code sequence. The receiver includes first and second correlators and threshold detectors adapted to detect PN signals with varying PN code sequence changes.

Abstract: A bidirectional direct sequence spread spectrum half-duplex RF modem. The RF modem can be applied to transmit and receive numerous types of analog and digital pulse modulation. The modem incorporates a SAW based correlator for performing the spreading and de-spreading functions in the transmitter and receiver. A programmable frequency synthesizer provides the frequency source for various signals in the modem including the local oscillator (LO), IF interrogating pulse and clock signals. An upconverter/downconverter provides frequency translation to the desired frequency band. Pulse gating and interrogating pulse shaping are employed to reduce the spectral side bands of the transmitted spread pulse. The RF modem operates as a analog or digital pulse transmitter and receiver. It is adapted to be generic and is versatile enough to be used in many different types of data communication systems, such as OOK, PWM and PPM.

Abstract: A modulation channelization and demodulation system based on orthogonal bipolar spreading vectors is provided that permits a variable information rate to be transmitted without inducing envelope fluctuations and permits multiple access without requiring the transmitter amplifiers to support the combined information rate of all users. The modulation system uses the vectors of a Hadamard matrix to form communication channels. The information rate on any channel may be doubled by using half the vector length to transmit information. The vector that is not non-orthogonal-in-the-half to the rate-doubled vector is preferably deactivated. In the same fashion, higher information rates may be provided through truncation of the transmission vector and the elimination of the resultant non-orthogonal vectors. A multi-channel receiver including a Fast Hadamard Transform structure comprised of controllable modified logic cells for performing the multi-rate communication of the present invention is illustrated.

Abstract: In an automobile on-board and/or portable telephone system capable of increasing the capacity of subscribers easily on the basis of changing of the information transmission bit rate, spread codes obtained by multiplying orthogonal spread codes (m in number) by a pseudo-random noise series are assigned to individual channels in the same cell in such a manner that the orthogonal spread codes are multiplied by some types of pseudo-random noise series having different phases, thereby making it possible to maintain the number of channels in the same cell at a value which is a multiple of the number of the orthogonal spread codes.

Abstract: A remote power meter monitoring system using spread spectrum transmitters, fast frequency shift keying, spread spectrum receivers and a computer. The spread spectrum transmitter uses a chip code generator, preamble register, address register data register and oscillator coupled to a microprocessor to transmit information in a direct sequence spread spectrum signal. The spread spectrum receiver acquires synchronization of the spread spectrum signal using a microprocessor to despread and detect the transmitted information, which relates to data from a power meter.

Abstract: An orthogonal complex spreading method for a multichannel and an apparatus thereof are disclosed. The method includes the steps of complex-summing ?n1WM,n1Xn1 which is obtained by multiplying an orthogonal Hadamard sequence WM,n1 by a first data Xn1 of a n-th block and ?n2WM,n2Xn2 which is obtained by multiplying an orthogonal Hadamard sequence W1,n2 by a second data Xn2 of a n-th block; complex-multiplying ?n1WM,n1Xn1+j?n2WM,n2Xn2 which is summed in the complex type and WM,n3+jPWM,n4 of the complex type using a complex multiplier and outputting as an in-phase information and quadrature phase information; and summing only in-phase information outputted from a plurality of blocks and only quadrature phase information outputted therefrom and spreading the same using a spreading code.