Abstract: A signal transmission apparatus and method for a mobile communication system are disclosed. Beamforming is performed on each symbol using the correlation as well as the independence between antennas, and then the beamformed symbols are transmitted. Thus, both the correlation between antennas and the independence between antennas are all considered, so that the gain according to the correlation between antennas can be also obtained. In addition, the additional gain would lead to enhancement of the symbol detection capability of the sending end, so that performance of the MIMO system can be remarkably heightened.

Abstract: A method for transmitting signal in a mobile communication system allocates symbols which will be transmitted to transmitting antennas appropriately as considering detection efficiencies of symbols on a higher order modulation constellation and correlation between antennas, and thereby independent symbol transmission can be made and independence between antennas can be improved to improve accuracy of symbol detection on a receiving end and signal transmitting function of the system can be improved. Therefore, a pair of symbols having the longest distance between symbols is arranged to a pair of antennas having higher correlation and a pair of symbols having the shortest distance between symbols is arranged to a pair of antennas having lower correlation. Also, symbols having higher detection efficiency are allocated to antennas having higher correlation and symbols having lower detection efficiency are allocated to antennas having lower correlation.

Abstract: A radio transmission apparatus for performing radio transmission by use of a plurality of carrier frequencies including signal processing systems for respective channels. Each signal processing system includes a transmission signal generator that modulates transmission data with a predetermined carrier frequency signal to generate a transmission signal, an amplifier that amplifies the transmission signal, and a variable band-pass filter connected to the output of the amplifier. The outputs of the signal processing systems are combined into a radio transmission signal. At least center frequency of a pass band of the variable band-pass filter can be changed, with the pass band determined based on the carrier frequency signal of the channel. The apparatus also includes a fault detector configured to detect a fault of each variable band-pass filter.

Abstract: The invention describes a method and apparatus for apparatus for controlling communications between a mobile cellular telephone and a cell of a cellular telephone network. The apparatus comprises a basestation, a duplexer, a first antenna and a second antenna. The basestation transmits and receives communications between the cell and the mobile cellular telephone. The duplexer is coupled to the basestation and separates transmitted communications from received communications at the cell. The first and second antennas are coupled to the duplexer, transmit signals from the basestation to the mobile cellular telephone and receive signals from the cellular telephone for the basestation, and are spatially diverse to allow a signal from the first antenna and a signal from the second antenna to be superimposed into a composite signal that is used for communications with the cellular telephone.

Abstract: A transceiver system according to the present invention transmits data utilizing the baseband and one or more frequency separated transmission bands. A baseband transmitter is combined with one or more transmitters that transmit data into one of the frequency separated transmission bands. A baseband receiver is combined with one or more receivers that receive data from the frequency separated transmission bands. Any combination of modulation systems can be utilized (e.g. PAM for the baseband and QAM for the frequency separated bands). A transceiver circuit or chip according to the present invention includes a transmitter and a receiver and communicates with a corresponding transceiver chip. In some embodiments, one baseband PAM transmitter is combined with one frequency separated QAM transmitter.

Abstract: A wireless communication system (40). The system comprises transmitter circuitry (42) comprising encoder circuitry (44) for receiving a plurality of symbols (Si). The system further comprises a plurality of antennas (AT1-AT4) coupled to the transmitter circuitry and for transmitting signals from the transmitter circuitry to a receiver (UST), wherein the signals are responsive to the plurality of symbols. Further, the encoder circuitry is for applying open loop diversity and closed loop diversity to the plurality of symbols to form the signals.

Abstract: Provided is a system and method for eliminating the effects of antenna coupling by increasing the isolation between closely mounted antennas on a portable wireless communications device. Increased isolation is achieved by providing a ceramic resonator in the path of each of the antennas. The ceramic resonator placed in the path of a particular antenna eliminates the effects of coupling caused by a particular one of the other antennas by rejecting signals associated with the particular antenna.

Abstract: In a wireless transmission system that transmits the same information in parallel using two or more different types of modulation schemes, such as a satellite-based digital audio transmission system transmitting two TDM signals and a single OFDM signal, a receiver processes the differently modulated signals to generate separate demodulated signals that are then combined to form a single combined signal for further processing (e.g., decoding). In one embodiment, the receiver applies a maximal ratio combining (MRC) technique to generate a single optimal ratio combined signal from the differently modulated signals. By combining the differently modulated signals using an MRC technique, the adverse affects of noise related to inter-symbol interference in the individual signals can be reduced and the complexity of hardware in the receiver can be reduced.

Abstract: A transmit processor that includes a transmit frequency domain equalizer (TX FEQ) that pre-compensates packets in the frequency domain to flatten transmit filter response to improve spectral mask and reduce PER. The TX FEQ taps may be selected so that the average power at output equals the average power applied to the input. The TX FEQ may be designed to yield 64 QAM packets with no quantization distortion at the input of an Inverse Fast Fourier Transform (IFFT) processor. The 64 QAM constellation map points and TX FEQ gain values are selected to avoid exceeding the bit resolution of the IFFT processor. The tones may be bound together into zones to reduce implementation complexity by reducing the number of TX FEQ taps.

Abstract: A base station for a wireless communication system is capable of transmitting signals that match the polarization state of a mobile station by including an antenna arrangement having at least one set of transmit antenna elements and at least one set of receive antenna elements, a transformation mechanism having at least one antenna port coupled to the antenna arrangement and at least one beam port, and an adaptive measurement and control mechanism coupled to the transmit and receive antenna port signals and configured to measure and adaptively control attributes of the transmit and receive antenna port signals.

Abstract: The invention provides a mobile communication apparatus of the diversity system including a plurality of transmitter-receivers of different transmission/reception systems wherein a drop of the antenna reception sensitivity of one system by an output from the antenna of the other system is minimized and the synchronism keeping accuracy is augmented and besides unnecessary dissipation of power is prevented.

Abstract: A wireless transmission device for communicating a plurality of audio streams to remote devices comprises a plurality of inputs for receiving a plurality of digital audio streams, a combiner connected to the inputs for combining control codes and the received audio streams in a predetermined format to form a signal wherein the control codes for controlling the operation of a remote device equipped for processing the signal to extract the audio streams therefrom in accordance with the predetermined format, and a transmitter connected to the combiner to transmit the signal for reception by the remote device. The transmitter may include an infra-red light emitter for transmitting the signal as an infra-red light signal.

Abstract: A point-to-multipoint or two-way communications system is provided by a nodal transmitter located in a node with a plurality of nodal antennas radiating different polarization signals about the node. The system includes subscriber stations with directional antennas adapted to receive signals radiated from the nodal transmitter. The system may additionally include capability for transmitting and radiating subscriber signals to the nodal transmitter location for two-way communications.

Abstract: The invention relates to a radio system and a data mission method. In the method of the invention, a transmitter codes a signal to be transmitted such that at least two non-orthogonal channels are obtained; the transmitter transmits the coded channels via at least two different transmit antenna paths; and a receiver receives the signal. The transmit antenna paths are divided into at least two different groups; and the signals to be transmitted through the different groups are weighted in the transmitter by means of changeable weighting coefficients determined for each group.

Abstract: A system and method for performing extended space-time processing. An improved symbol decision is generated of a desired sub-channel of the signal vector by first generating a baseline decision for the sub-channel. A contribution of a strongest sub-channel is subtracted from the signal vector to generate a modified signal vector. The modified signal vector is multiplied by a unitary matrix generated from a QR decomposition of another channel matrix. Channel interference of the remaining sub-channels of the modified signal vector is cancelled from a remaining sub-channel.

Abstract: A system and related methods for introducing intra-channel spatial diversity within a multi-carrier wideband communication channel is presented. In accordance with one aspect of the present invention, developed more fully below, a method is presented comprising receiving information for transmission to a receiver, and generating a plurality of sub-carriers to redundantly transmit the information to a user over a multi-carrier wireless communication channel, wherein each of the sub-carriers is dynamically modified by a set of complex weights to ensure that each of the sub-carriers of the wireless communication channel propagates along a different physical path to the receiver.

Abstract: A beam having the best performance for the present downlink transmits the signal carrying information. In another beam transmitted, in a corresponding manner having the best performance in regard to the next mobile station to be communicated in a next time slot, a signal is created which has a low cross correlation relative to the present signal carrying information. The average power in the direction to the next mobile station to be communicated in the next TDMA time slot will be given by the sum of the average power of the two signals after amplification by the respective antenna pattern. This takes place because the cross correlation between the signals is low due to which fact the summed signal will show a power addition but not a coherent addition. This is feasible as the summed signal is not be decoded by the next mobile station, but used entirely as a measurement of power.

Abstract: A data transmitting/receiving apparatus and method using an antenna array in a mobile communication system. A Node B measures a transmission status of each transmission antenna, classifies transmission data according to priority, and transmits to a UE high-priority data through a transmission antenna at a relatively good transmission status and low-priority data through a transmission antenna at a relatively poor transmission status.

Abstract: A single base station supports the non-diversity transmission of a first digital signal type and the diversity transmission of a second digital signal type. The base station includes primary channel boards for modulating and encoding a first digital signal type and secondary channel boards for modulating and encoding a second digital signal type. A first group of transmit radio modules accept the first digital signal type and the second digital signal type and provides a composite electromagnetic output signal. Each transmit radio module is associated with a different sector. A second group of transmit radio modules accept the second digital signal type from secondary channel boards and provide a diverse electromagnetic output signal for complementing the composite electromagnetic output signal.

Abstract: A communication system for communicating utility data from a utility distribution network comprises a transmitter for transmitting the utility data. The transmitter comprises a processor that modulates the utility data into a plurality of carrier frequencies. A modulator is connected to the processor and receives the modulated utility data. The modulator modulates the modulated utility data in the AM frequency band forming multi-tone modulated data wherein the transmitter transmits the multi-tone modulated data/transmitted information in the AM frequency band. The communication system also comprises a receiver that receives the transmitted information. The receiver comprises a demodulator that receives the transmitted information and demodulates the transmitted information into a received signal. A processor is connected to the demodulator and receives the demodulated information.

Abstract: A power control system for a multi-carrier base station transmitter is capable of controlling power levels of individual RF carriers. The power control system has a multi-channel conversion system for generating a plurality of analog reference signals corresponding to a plurality of digital input signals. The multi-channel conversion system also generates an analog multi-carrier signal and samples the multi-carrier signal. The multi-carrier signal represents a summed amplification of the digital input signals. A correlating power detection system is connected to the multi-channel conversion system and generates digital total power control signals based on the analog reference signals and the analog sampled multi-carrier signal. A feedback conversion module is connected to the multi-channel conversion system and the correlating power detection system and individually controls amplification of the digital input signals based on the total power control signals.

Abstract: A methodology is provided for processing carriers in a wireless application whereby the outputs of a multiplicity of modulated RF signal sources are combined into a single RF signal stream, that single RF signal stream being thereafter divided among the inputs of another multiplicity of RF power amplifiers. The outputs of that multiplicity of RF power amplifiers are then recombined, filtered and provided as an input to a transmission antenna.

Abstract: A high density electronic switching matrix (ESM) includes several splitting modules (200) arranged along a first axis, each including a signal input (202) and several splitter outputs (204). The ESM (500, 600) further includes several switching modules (400) arranged along a second axis perpendicular to the first axis. Each switching module (400) includes switching inputs (402) coupled individually to an output of each of the splitting modules (200). The ESM (500, 600) is further characterized by couplings between the splitter modules and the switching modules. The couplings are formed by mating male and female connectors (300) integrated into the splitting modules and the switching modules. The couplings support extremely high frequency operation. The splitting modules (200) and the switching modules (400) may thus be coupled closely together to form a dense, high frequency, switching matrix, and may be stacked upon one another.

Abstract: Described herein is a method and apparatus for transmission that provides the performance of space time spreading (STS) or orthogonal transmit diversity (OTD) and the backwards compatibility of phase sweep transmit diversity (PSTD) without degrading performance of either STS or PSTD using a symmetric sweep PSTD transmission architecture. In one embodiment, a pair of signals s1, and s2 are split into signals s1(a) and s1(b) and signals s2(a) and s2(b), respectively. Signal s1 comprises a first STS/OTD signal belonging to an STS/OTD pair, and signal s2 comprises a second STS/OTD signal belonging to the STS/OTD pair. Signals s1(b) and s2(b) are phase swept using a pair of phase sweep frequency signals that would cancel out any self induced interference. For example, the pair of phase sweep frequency signals utilize a same phase sweep frequency with one of the phase sweep frequency signals rotating in the opposite direction plus an offset of &pgr; relative to the other phase sweep frequency signal.

Abstract: The present inventions provide methods and systems for reducing the peak to average power ratio of a multi-carrier signal. Reducing the peak to average power ratio of a signal ensures that amplifiers and transmitters are not saturated, causing loss of data. Further, reducing peak to average power ratios reduces the consumption of power during transmission. Peak to average power ratios are reduced by applying a peak reduction signal component to one or more of the plurality of information signals that make up the multi-carrier signal. In one embodiment the peak reduction signal is a basis function of the communication system. The information signal is mapped to duplicate constellation points, which may be easily decoded by a receiver by performing a modulo operation. Negation of the peaks may be performed iteratively to remove any peaks produced during prior peak reduction operations.

Abstract: A parallel operation system of transmission amplifiers enable the parallel running by the two distortion compensation amplifiers using the digital pre-distorter system and to provide a parallel operation system of the transmission amplifiers that makes it possible to switch to respective single running easily. The parallel operation system includes first and second transmission amplifiers which receive common input signals for outputting amplified signals from respective ones; and a coupling unit which combines outputs of the first and second transmission amplifiers, to provide as its output; the first and second transmission amplifiers each having a main amplifier; and a modulation unit disposed on the input side of the main amplifier; wherein the output of one of the modulation units included in the first and second transmission amplifiers is fed in common to the main amplifiers included in the first and second transmission amplifiers.

Abstract: A communication device (100) including a receiver (110), a demodulator (120), a frequency dependent LF amplifier (130) as well as a frequency dependent decoder (150) receives a HF signal (105) onto which speech information and data information are modulated on a single carrier. The LF signal (125) provided from demodulator (120) includes two separated frequency bands for speech and data. The amplifier (130) makes audible the speech via a speaker (140) and the decoder (150) evaluates the data information, displays the same at a display (160) and controls the amplifier (150,155), respectively.

Abstract: By using switches (110) that are synchronously controlled, the present invention permits connection of a plurality of antennae (130) to a plurality of radio front end units (radios 120) so that at any time any of the radios (120) may be assigned to any of the antennae (130) without leaving any radio (120) unconnected. A controller (140) arbitrarily assigns, at any time, any of the radios (120) to any of the antennae (130) while keeping every radio (120) connected to an antenna (130).

Abstract: The invention relates to a method and an arrangement for establishing a connection between two fixed nodes in a mobile radio system. Adaptive antennas are utilized to achieve narrow beams. The connection is established via a reflecting body.

Abstract: A radar for locating and tracking objects based on the use of a pulsed waveform, each pulse of the pulsed waveform being made up of a plurality of spectral components having different frequencies, including an antenna. The radar further includes a transmitter operatively coupled to the antenna for generating the plurality of spectral components that make up each pulse of the pulsed waveform and a receiver operatively coupled to the antenna for receiving signals at the frequencies of the plurality of spectral components.

Abstract: A mobile communication system includes a base station connected to a backbone network, and a mobile station configured to communicate with the base station using a radio frequency. The system has a first communication mode, in which a first radio frequency is used for an uplink and a second radio frequency is used for a downlink; a second communication mode, in which the first radio frequency is used for the uplink, and the second radio frequency is shared by the uplink and the downlink; a third communication mode, in which the second radio frequency is used for the downlink, and the first radio frequency is shared by the uplink and the downlink; and a mode switcher configured to switch the first through third communication modes in accordance with data transfer volumes on the uplink and the downlink.

Abstract: A power efficient indoor radio base station for use with wireless cellular telecommunication systems is disclosed. A small unitary package design is achieved by reducing the level of power dissipation, and subsequently, the size of the heat sink required for heat dissipation. In a preferred embodiment of the present invention, a plurality of transmitter signals are combined in a hybrid combiner to generate a pair of output signals. A first output signal is transmitted through a dipole antenna resulting in vertical polarization and a second output signal is transmitted through a horizontal antenna producing horizontal polarization. Further, a phase shift of 90° is introduced between the signals prior to transmission. The resulting simultaneous transmission of the perpendicularly oriented signals yields a substantially circular polarized field in the area of coverage.

Abstract: A signal distributing/synthesizing apparatus includes a 4-terminal hybrid circuit, first and second antennas, a pseudo-antenna, and first to third 4-terminal switches. The 4-terminal hybrid circuit distributes the signal input to the first terminal to the second and third terminals, and synthesizes the signals input to the second and third terminals into a signal to be output to the first terminal. The first and second antennas form a radio transmission channel for an output signal from the signal 4-terminal hybrid circuit. The pseudo-antenna forms a pseudo-radio transmission channel for an output signal from the 4-terminal hybrid circuit. The first switch complementarily switches/connects a first broadcasting unit and the first antenna to the first terminal of the 4-terminal hybrid circuit and the third switch. The second switch complementarily switches/connects a second broadcasting unit and the second antenna to the second terminal of the 4-terminal hybrid circuit and the third switch.

Abstract: An automated transmit combiner monitoring system (100) for an RF radio transmitter system includes a transmitter (101) for providing a primary source of radio frequency (RF) energy and an isolator network (105,107) for isolating the output of the transmitter (101) from secondary sources of RF energy. A transmitter combiner junction (109) is used for enabling the transmitter (101) to provide RF energy to a single antenna (111) while a dummy load (113) is used for loading any unwanted RF energy from the transmitter (101) that is received from the isolator network (103,105). An RF detector (115) is then used for measuring RF energy from the dummy load and an alarm reporting device (119) then monitors the system to provide an alert based on RF energy measured outside a predetermined threshold.

Abstract: A multi-channel transmission system and method provide peak power smoothing without additional in-band interference. The system includes a multi-carrier waveform generator for reducing peak amplifier power required to transmit a digital multi-carrier waveform based on a plurality of digital carrier waveforms. A signal conversion system generates an analog multi-carrier waveform based on the digital multi-carrier waveform. The analog multi-carrier waveform has a center frequency and a desired gain over the original signal. A bandpass filter is coupled to the signal conversion system for restriction of the analog multi-carrier output waveform to a desired transmission bandwidth. The multi-carrier waveform generator has a nulling waveform generator coupled to a plurality of single carrier waveform modules for generating a digital nulling waveform based on the retrieved data. The nulling waveform reduces a peak power of the multi-carrier waveform and results in a reduced signal envelope.

Abstract: A satellite communication system includes at least one spacecraft in geosynchronous orbit for providing a plurality of beams on the surface of the earth, and a plurality of ground stations individual ones of which are located in one of the beams for transmitting uplink signals to the spacecraft. The spacecraft has a plurality of receivers for receiving a plurality of the uplinked signals from ground stations, a frequency translator for translating the received uplink signals to a transmission frequency of a plurality of downlink signals, and a plurality of transmitters for transmitting the plurality of downlink signals within the same beams as the corresponding uplink signals. Each transmitter includes a combiner for combining together a plurality of frequency translated signals and a power amplifier, such as a TWTA, for amplifying the combined plurality of frequency translated signals.

Abstract: In a multiple-carrier modulation system, each carrier signal of the multiple carrier system is distributed, recombined, optionally band pass filtered, and transmitted to downlink devices such as cellular phones. The distribution and recombination is performed by either a space-fed technique or through the use of a Rotman lens fed in reverse. The phases of the distributed signals are controlled to be coherent when recombined. Also, a capacity of the multiple carrier system is enhanced through polarization of the carriers in a space-fed version of the system.

Abstract: A radio communication system comprises a communication channel between two terminals each comprising a plurality of antennas (108). The communication channel comprises a plurality of paths, and at least one of the terminals comprises a receiver having means (306, 308) for determining the directions from which the strongest signals are received, corresponding to paths between the terminals. The terminal may also include a transmitter having means (302) for separating a signal into a plurality of parts, each having a reduced bit rate, and transmitting the parts in respective directions corresponding to those from which the strongest signals are received.

Abstract: The present invention provides a diversity transmission system. The diversity transmission system includes a diversity transmitter receiving incoming symbols. The diversity transmitter includes at least one transmitter antenna transmitting a plurality of multi-carrier modulated signals. Each multi-carrier-modulated signal includes a corresponding processed symbol sub-block stream. Each symbol of the processed symbol sub-block stream is based on a linear transform of a plurality of incoming symbols. The diversity transmission system further includes a diversity receiver. The diversity receiver includes at least one receiver antenna receiving the plurality of multi-carrier modulated signals after the multi-carrier modulated signals having been modified by transmission channels between the transmitter antennas and the receiver antenna.

Abstract: In a method of calibrating a quadrature transmitter, a first calibration signal is injected into an in-phase transmit branch of the quadrature transmitter, and a second calibration signal is injected into a quadrature transmit branch of the quadrature transmitter. The first and second calibration signals are injected before performing up-conversion in the transmitter and are produced by first and second digital signals. A detector detects an up-converted signal. The detected up-converted signal is digitized. The in-phase and quadrature transmit branches are calibrated by alternately determining the first and second calibration signals while at least varying respective most significant bits of the first and second digital signals, upon said varying the at least most significant bits keeping calibration bit values that correspond to minimum values of the digitized detected up-converted signal.

Abstract: Reliable transmission of signals in a multi-channel system is achieved by transferring signal inputs from a defectively operating or inoperative transmitter to another transmitter which continues to transmit other channels. At least two transmitters are operated normally, each transmitting its own block of channels. A sensor detects when the output of one transmitter is improper or non-existent, and causes a change-over switch to operate. Operation of the switch adds the block of channels which had come from the one transmitter to the other (or one or more) of the transmitters, so that the remaining transmitter or transmitters now provide all the channels.

Abstract: The present invention provides for methods and apparatus for fragmenting a single message and sending the message fragments over multiple independent networks to a single receiving unit. The receiving unit then reassembles the message fragments to generate the original message. The preferred apparatus embodiment is a wireless radio frequency modem that can both receive and transmit fragmented messages over multiple independent networks.

Abstract: A wireless device that performs transmission of multiple wireless channels arranged within the used wireless frequency band at prescribed frequency intervals. Multiple wireless channels are divided into two systems, odd-numbered and even-numbered with gaps of one, or into two or more systems with gaps of two or more. Included are transmission amplifiers that transmit in common for each system, multiple band elimination filters connected in cascades to reduce the adjacent-channel leakage power in each system, and circulators that compose the transmission signals of each system. Transmission is done from an antenna via a transmission-reception signal splitter.

Abstract: Antenna systems are used for transmitting common overhead channels (pilot, sync, and paging channels) over a whole sector while transmitting and receiving unique traffic channels on individual beams in the sector. Each beam in the sector is transmitted at a frequency offset from other beams in the sector. The offset frequency is chosen such that the effect of cancellation of the pilot channel caused by the summing of signals from multiple beams is minimized. Alternative, each beam in the sector can have a time dependent phase offset relative to each other to minimize the effect of cancellation of the pilot channel caused by the summing of signals from multiple beams. System capacity is substantially increased since the number of traffic carrying beams per sector is increased without using more pilot channel PN offsets. Beams are fixed and the same antennas are used for the overhead channels as the traffic channels, obviating the need for complex algorithms and calibration procedures.

Abstract: The invention relates to a wireless radiofrequency data communication system comprising:

Abstract: An improvement in the design and deployment of collocated radio transceivers for high-speed wireless Internet access accomplished by increased isolation brought about by wrapping each transceiver in a shield of mild steel, enclosing collocated transceivers and associated equipment in non-reflective enclosures, use of low loss RF coaxial cables, and use of high isolation parabolic horn antennas.

Abstract: An access point is provided for use in a wireless network having a system backbone and a plurality of mobile terminals. The access point includes a communication circuit coupling the access point to the system backbone, and a first transceiver for wirelessly communicating with at least one of the plurality of mobile terminals on a first communication channel. In addition, the access point includes a second transceiver for wirelessly communicating with at least another of the plurality of mobile terminals on a second communication channel different from the first communication channel.

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 invention provides a power sharing amplifier system having an N by N transform matrix circuit, N amplifiers and an N by N inverse transform matrix circuit. The N by N transform matrix circuit has N input ports that respond to M input signals and provide N transform matrix input signals, where M is less than N. The N by N transform matrix circuit features at least one input port that does not receive an input signal but instead is coupled to ground. The N amplifiers respond to the transform matrix input signals and provide N amplified transform matrix input signals. The N by N inverse transform matrix circuit responds to the N amplified transform matrix input signals and provides N inverse transform matrix amplified output signals to output ports. Moreover, the N by N inverse transform matrix circuit features at least one output dissipation port that is coupled to ground to dissipate the intermodulation products contain thereon.

Abstract: A method and apparatus for wireless transmission of a digital bit stream. The present method employs diversity techniques to minimize multipath fading. Digital bits are converted into symbols and the symbols are provided to a number of diversity branches. Each diversity branch has its own antenna. The symbols sent to each diversity branch may be multiplied by a different phase factor or amplitude factor. The phase factors and amplitude factors may be randomly selected. Also, wireless channels can be monitored for channel quality. In this case, the channel quality measurements are used to select the phase factors and the amplitude factors. Also, the symbols can be grouped into frames before transmission. In this case, the frames can be multiplied by matrices comprising phase factors and amplitude factors. Also in this case, the frames can undergo cyclic shifting, which provides an additional measure of diversity.