Abstract: Communication signal processing entails generating an overall signal correlation estimate that reflects overall impairment present in a received signal before despreading. Processing further includes parametrically constructing one or more component-specific correction terms as a function of one or more component signal correlation estimates, each estimate reflecting a particular component of the overall impairment. Combining weights are derived, as a function of this overall estimate and the correction term(s), so that they exclude the contribution of the impairment component(s) to the overall impairment. These weights are used to combine signal samples in an equalization process. As the combining weights exclude the contribution of the impairment component(s) to the overall impairment, the equalization process utilizing the weights exclusively suppresses impairment that is not attributable to the component(s).

Abstract: A radio frequency communication system. The system includes a radio frequency transmitter and a radio frequency receiver, wherein the radio frequency transmitter includes a modulation circuit and an RF modulator, wherein the radio frequency transmitter maps each block of K information bits into a block of N transmit symbols, transforms the block of N transmit symbols by using symbol block repetition and spreads the symbol blocks by multiplying the symbol blocks by a predefined chirp signal, and wherein the radio frequency receiver includes a chirp receiver operable to receive, demodulate and digitize a modulated radio frequency (RF) signal to form a digital baseband signal, and to recover a signal modulated using interleaved single carrier chirp spread spectrum modulation.

Abstract: A method for receiving a chirp signal at a receiver, the chirp signal communicated over a link from a transmitter, the chirp signal comprising at least one symbol, each symbol comprising a plurality of identical chirps, each chirp encoding a symbol value, the method comprising: determining a measure indicative of error in the received chirp signal; determining the number of coherent integrations and non-coherent integrations to apply per symbol in dependence on the indicated error; for each symbol, coherently and non-coherently integrating the plurality of chirps in accordance with the determined numbers so as to form an integrated symbol; and for each symbol, decoding the symbol value from the integrated symbol.

Abstract: Provided are a receiver for a real time locating system (RTLS) and a method of receiving a signal in the RTLS. The receiver includes a down converter converting a radio frequency (RF) signal into a base band signal, a matched filter filtering the converted signal using an optimal receiving filter in view of a signal-to-noise ratio (SNR) such as a shaping filter used for a transmitter, an adaptive transversal filter (ATF) estimating an interference signal with an output of the matched filter, and filtering the output to remove interference of a heterogeneous signal of the same frequency band, a de-spreader multiplying an output of the matched filter and a code according to DSSS modulation used for spreading when a tag signal is modulated, and performing chip-matched filtering to obtain a value of correlation energy, and a detector detecting original transmission data using the correlation energy value.

Abstract: A system for dual chirp modulation includes a transmission unit, a receiving unit, and a transmission channel. A modulation module of the transmission unit is configured to receive binary data and modulate the binary data by a first dual chirp sequence and a second dual chirp sequence for generating an output signal. Then the output signal is converted from digital form to analog form by a digital to analog converter. A transmission channel is configured to receive the output signal converted to analog form, wherein the output signal converted to analog folio passes the transmission channel for generating a received signal. An analog to digital converter converts the received signal from analog form to digital form and a demodulation module demodulates the received signal with digital form, by the first dual chirp sequence and the second dial chirp sequence, for recovering the binary data.

Abstract: An apparatus and method for signal emitters determining and using a reduced number of discrete frequency transmitters based on frequency segmentation and degradation analysis of a candidate filter configuration compared to an original waveform input signal for acceptability determination in view of desired system parameters. A method that configures a device to produce a complex waveform over a desired range of frequencies is provided. Configuring a device can include filtering to reduce a number of frequencies which in turn is used to reduce signal emitters and configuring resulting reduced signal emitters includes producing a desired complex waveform over a desired range of frequencies.

Abstract: Technologies are generally described for cognitive radio spectrum sensing via Code Division Multiple Access (CDMA) receiver coding. A CDMA module in the front-end of a cognitive radio system may be used to sense spectrum. When the system is not decoding or transmitting signals, a modified CDMA receiver coding may replace a pseudorandom code used in decoding with relatively pure, non-random detection frequency to scan for energy from primary users of the spectrum. Multiplication of the received signal by spectrally pure codes in place of the CDMA code renders the CDMA processor effectively a scanning spectrum analyzer and may detect energy at multiple frequencies. The allocation of sub-bands and/or timing may be adjusted to account for the detected energy.

Abstract: A system and method are disclosed that allow changes of a modulation and coding scheme (MCS) without overhead signaling. A priori, a network device and a user device know the manner in which the MCS will be changed. In one embodiment, the network device indicates the MCS to be used to decode a second portion of a message in a first portion of the message. In another embodiment, the user device blind detects the MCS used over a sub-set of MCSs.

Abstract: A transmitter configured to communicate a data chirp signal to a receiver, the chirp signal comprising at least one symbol, each symbol comprising one or more identical chirps, each symbol having a different gradient to another symbol in the chirp signal, each chirp encoding a symbol value, the transmitter comprising: an address encoding module configured to encode an address associated with the communication via the sequence of gradients of the symbols in the chirp signal; a data encoding module configured to encode data in the chirp signal via the symbol value of each chirp; and a transmitting module configured to transmit the data chirp signal to the receiver.

Abstract: A system for dual chirp modulation includes a transmission unit, a receiving unit, and a transmission channel. A modulation module of the transmission unit is configured to receive binary data and modulate the binary data by a first dual chirp sequence and a second dual chirp sequence for generating an output signal. Then the output signal is converted from digital form to analog form by a digital to analog converter. A transmission channel is configured to receive the output signal converted to analog form, wherein the output signal converted to analog folio passes the transmission channel for generating a received signal. An analog to digital converter converts the received signal from analog form to digital form and a demodulation module demodulates the received signal with digital form, by the first dual chirp sequence and the second dial chirp sequence, for recovering the binary data.

Abstract: A method of synchronizing the frequency and timing of a receiver with a synchronization chirp signal from a transmitter, comprising: receiving the synchronization chirp signal, the synchronization chirp signal comprising a sequence of symbols, the sequence of symbols including at least a first symbol having a first gradient g1 and a second symbol having a second gradient g2, wherein the magnitudes of the first gradient and the second gradient are both greater than one, and the magnitude of the first gradient is different to the magnitude of the second gradient; correlating the sequence of received symbols with expected symbols to form a correlator output; determining timing and frequency offsets between the transmitter and the receiver from the correlator output; and adjusting the timing and frequency of the receiver by the determined timing and frequency offsets.

Abstract: An apparatus and technique for measuring and coping with interfering signals in a wireless communications system. The apparatus and technique rapidly and regularly measures the signals present in the wireless communication system's band of operation. The apparatus and technique then makes this information available to all the transceivers on the network, so that each transceiver has information the interference other transceivers see, and the system can make intelligent decisions about radio transmission parameters to optimize the network performance.

Abstract: An aspect of the invention is directed to a method for maintaining the synchronisation of a receiver with a chirp signal sent over a link from a transmitter. The chirp signal comprises at least a first chirp having a gradient greater than one. The transmitter may encode data on to the signal by varying the properties of the chirps it transmits. The receiver correlates the received first chirp with an expected reference chirp to produce a set of correlation results. Should the gradient of the received chirp match the gradient of the expected reference chirp, then a distinct large “prompt” peak will be present having a greater magnitude than any other correlation peaks present in the correlation results. Transmitted data symbols may be inferred from properties of this prompt peak, for example its position in samples in the correlation results.

Abstract: A device for decoding code symbols which are interfered with a distortion during a predetermined distortion time interval includes a reliability information generator to provide reliability information based on the code symbols and a decoder to decode the code symbols into code words. The decoder is configured to decode the code symbols based on weighted reliability information, wherein the weighted reliability information is generated from the reliability information by applying a first weight during times not coinciding with the distortion time interval, and by applying a second weight different from the first weight during times coinciding with the distortion time interval.

Abstract: Technologies are generally described for cognitive radio spectrum sensing via Code Division Multiple Access (CDMA) receiver coding. A CDMA module in the front-end of a cognitive radio system may be used to sense spectrum. When the system is not decoding or transmitting signals, a modified CDMA receiver coding may replace a pseudorandom code used in decoding with relatively pure, non-random detection frequency to scan for energy from primary users of the spectrum. Multiplication of the received signal by spectrally pure codes in place of the CDMA code renders the CDMA processor effectively a scanning spectrum analyzer and may detect energy at multiple frequencies. The allocation of sub-bands and/or timing may be adjusted to account for the detected energy.

Abstract: Disclosed is a frequency hopping modulation method in a communication system. The method includes: generating a frequency hopping pattern according to a hopping frequency's level; generating a hopping frequency through use of the frequency hopping pattern; modulating an original signal to a frequency hopping spread signal by multiplying the original signal by the hopping frequency; generating a chirp pulse code for diversifying the frequency hopping spread signal; and modulating the frequency hopping spread signal to a chirp pulse signal by multiplying the frequency hopping spread signal by the chirp pulse code.

Abstract: A method and apparatus for detecting a jammer comprising sampling an input signal; downconverting and sampling the input signal to generate a sampled downconverted (SD) input signal; comparing the sampled input signal to a wideband threshold THWB, and comparing the SD input signal to a narrowband threshold THNB; generating a wideband (WB) interrupt signal based on the comparison to the THWB, and generating a narrowband (NB) interrupt signal based on the comparison to the THNB; and generating a composite interrupt signal based on at least one of WB interrupt signal and NB interrupt signal. In one aspect, the apparatus comprises a wideband jammer detector for generating a WB interrupt signal to indicate a wideband jammer; a narrowband jammer detector for generating a NB interrupt signal to indicate a narrowband jammer; and interrupt logic for generating a composite interrupt signal based on one of WB interrupt signal and NB interrupt signal.

Abstract: Methods and systems for sending a broadcast message in frequency hopping and other systems. Instead of sending a complete message separately to each device, a relatively small packet or “chirp” is sent. These chirps are either targeted at known devices or sent in a manner to sweep the RF band. Devices that hear the chirps get information about the channel and/or time that the broadcast data will be sent. These devices then listen for the broadcast data as instructed, e.g., at the specified time on the specified channel. A system may alternatively, or in addition, use a scheduled hopping sequence break as a broadcast moment. Such a broadcast moment can be scheduled to periodically interrupt the node hopping sequences so that, at such times, many or all nodes are scheduled to be on the same channel for potential broadcasts.

Abstract: Disclosed herein is a power line channel-adaptive communications system and method. The power line channel-adaptive communications system includes a transmitting end, a channel-adaptive controller, and a receiving end. The transmitting end generates an adaptive chirp symbol signal of a preset type for transmission data according to a channel state of the power line, modulates the generated adaptive chirp symbol signal in any one of first and second transmission modes, and transmits the modulated adaptive chirp symbol signal via the power line channel. The channel-adaptive controller controls the type and transmission mode of the adaptive chirp symbol signal. The receiving end restores the transmission data by demodulating the adaptive chirp symbol signal, received via the power line channel, in any one of the first and second transmission modes according to the channel state of the power line.

Abstract: This disclosure is directed to wireless communication systems having a receiver capable of detecting chirping radar pulses. The systems and methods include processing an input signal to obtain a spectral analysis that identifies which frequency exhibits maximum signal magnitude at a given time and determines a rate of change that frequency. By determining that the rate of change is within parameters established by the pulse width range and the chirping bandwidth range, the signal can be identified as a chirping radar pulse. By comparing the rate of change to known characteristics, the signal can be identified as a chirping radar pulse. Suitable characteristics include parameters for the rate of change established by the pulse width range and the chirping bandwidth range and linearity of the rate of change.

Abstract: Synchronization of a primary link which transitions between clear mode and spread mode is achieved and maintained using a secondary link. When transitioning from clear mode to spread mode, a primary transmission delta phase is adjusted by the difference between a secondary reception delta phase and the primary transmission delta phase; and a primary reception delta phase is adjusted to be equal to a secondary transmission delta phase.

Abstract: A communications system includes a modulator for generating a chirp signal aimed at spreading the frequency spectrum of an information signal over a specified spectral bandwidth of a communications channel. The chirp signal has initial and final instantaneous frequency. The chirp signal is controlled from an in-phase control signal and a quadrature-phase control signal to have, in a complex plane, constant amplitude and instantaneous phase. The instantaneous frequency is defined by the speed the instantaneous phase is changed in the complex plane by the in-phase and quadrature-phase control signals; the instantaneous frequency is linearly changed between initial and instantaneous frequencies over the whole duration of the chirp signal; the initial and final instantaneous phases of the chirp signal are identical.

Abstract: A method of synchronising the frequency and timing of a receiver with a synchronisation chirp signal from a transmitter, comprising: receiving the synchronisation chirp signal, the synchronisation chirp signal comprising a sequence of symbols, the sequence of symbols including at least a first symbol having a first gradient g1 and a second symbol having a second gradient g2, wherein the magnitudes of the first gradient and the second gradient are both greater than one, and the magnitude of the first gradient is different to the magnitude of the second gradient; correlating the sequence of received symbols with expected symbols to form a correlator output; determining timing and frequency offsets between the transmitter and the receiver from the correlator output; and adjusting the timing and frequency of the receiver by the determined timing and frequency offsets.

Abstract: A method of communicating a data chirp signal from a transmitter to a receiver, the data chirp signal including a sequence of symbols, each symbol encoding a first symbol value and a second symbol value such that the data chirp signal includes a first symbol value sequence and a second symbol value sequence, the first and second symbol values being encoded via different properties of the symbol, the first symbol value sequence being selected from values in a primary predetermined sequence and a secondary predetermined sequence, the method including: selecting consecutive values of the first symbol value sequence from values in consecutive sequence positions of the primary predetermined sequence and the secondary predetermined sequence; encoding first data in the chirp signal via the selected first symbol value sequence; encoding second data in the chirp signal via the second symbol value sequence; and transmitting the data chirp signal to the receiver.

Abstract: A signal processor performs a signal transform of a signal, and comprises a signal demodulator for demodulating said signal by a first chirp signal having a first chirp rate to obtain a reduced bandwidth chirped signal, a filter for filtering the reduced bandwidth chirped signal and delaying the reduced bandwidth chirped signal by an interval proportional to a reciprocal of said first chirp rate, a signal modulator for modulating said filtered signal by a second chirp signal having a second chirp rate to obtain an increased bandwidth chirped signal and to provide a time domain output spectrum of said signal, and wherein each of said first chirp signal and said second chirp signal is a complex signal representing a linear frequency modulated chirp.

Abstract: There is provided a channel estimating method of performing frequency conversion by a first fast Fourier transformation on a reception signal and extracting a desired signal after demodulating the reception signal, and deriving electrical energy against time delay of a channel by inverse fast Fourier transformation of the extracted result, wherein: values of a low pass filter, having an output from oversampling the input to the first fast Fourier transformation, are thinned by a plurality of thinning circuits with the same synchronization and different discrete times, and based on the outputs of the plurality of thinning circuits, the electrical energy against time delay related to the reception signal arrival time position is derived by respectively performing the first fast Fourier transformation and the inverse fast Fourier transformation.

Abstract: A method for receiving a chirp signal at a receiver, the chirp signal communicated over a link from a transmitter, the chirp signal comprising at least one symbol, each symbol comprising a plurality of identical chirps, each chirp encoding a symbol value, the method comprising: determining a measure indicative of error in the received chirp signal; determining the number of coherent integrations and non-coherent integrations to apply per symbol in dependence on the indicated error; for each symbol, coherently and non-coherently integrating the plurality of chirps in accordance with the determined numbers so as to form an integrated symbol; and for each symbol, decoding the symbol value from the integrated symbol.

Abstract: An electromagnetic transmission system is provided, comprising: M chirp generators, each operating at a first frequency, each of the M chirp generators being configured to generate an ith digital chirp portion comprising (1/M)th of a digital chirp signal having a set ramp rate; a parallel-in serial-out register configured to receive the M digital chip portions in parallel at the first frequency, and configured to output the M digital chip portions in series as the digital chirp signal at a second frequency; and a digital-to-analog converter operating at the second frequency and configured to convert the digital chirp signal into an analog chirp signal, wherein i is an index that goes from 1 to M, and wherein the second frequency is M times the first frequency.

Abstract: A radio frequency communication system includes a radio frequency transmitter having a chirp generator operable to transmit a first chirp signal, and transmit a second chirp signal that is circular shifted relative to the first chirp signal. A receiver receives the first chirp signal and the second chirp signal, such that the proportion of phase offset between the first and second chirp signals is proportional to the frequency offset of the received signals. The first and second chirp signals are despread, and the phase difference between the first and second chirp signals is used to determine a frequency offset of the received first and second chirp signals that is proportional to the phase difference between the first and second chirp signals.

Abstract: A method of communicating a chirp signal from a transmitter suitable for receipt at a proximal receiver and a distal receiver, the chirp signal including a plurality of packets, each packet including at least one symbol, each symbol including one or more identical chirps, the method including: generating the chirp signal by interleaving constituent packets of: (i) a first set of packets encoded with first data, each packet including one or more symbols having a first time period t1, and (ii) a second set of packets encoded with second data, each packet including one or more symbols having a second time period t2, where t1<t2; and transmitting the generated chirp signal.

Abstract: Distance between two radio frequency devices is estimated by receiving a plurality of spread spectrum chirp signals frequency offset from one another, and evaluating the received plurality of spread spectrum chirp signals for relative phase shifts between the plurality of spread spectrum chirp signals. A fine propagation time is derived using the phase shifts between the spread spectrum chirp signals. A frequency domain despreading window is shifted to reduce the influence of time-delayed near multipath signals in receiving the plurality of spread spectrum chirp signals.

Abstract: The cognitive radio system and method uses a wideband chirp signal. A cognitive radio base station broadcasts the low power reference wideband chirp signal with bandwidth covering the sensed spectrum. At the receiver, a Fast Fourier Transform is applied to the output of a chirp signal matched filter. The filter output is fed to decision circuitry, where a threshold value is set to decide the minimum spike's amplitude to determine frequencies utilized by primary users. Using reference chirp signal and its matched filter eases sensing computational complexity and improves the quality of sensing, thereby offering enhanced cognition at the CR receiver.

Abstract: A method (10) of providing a radar high range resolution (HRR) profile of a target comprises: generating and transmitting a stepped-frequency waveform radar signal (12); sampling echo signals to generate at least one receiver sample for each frequency step (14); generating a Fourier transform (FT) of each receiver sample to form frequency domain receiver samples (16); spectrally stitching the frequency domain receiver samples to form a stitched spectrum (18); applying a spectral scaling comprising the ratio of a reference wideband chirp spectrum to a reference spectrally stitched spectrum (20) to the stitched spectrum to form a scaled spectrally stitched spectrum; generating a cross-correlation of the scaled spectrally stitched spectrum and the reference spectrally stitched spectrum (22).

Abstract: A method for receiving chirp signals at a receiver device according to a protocol in which each chirp signal has a gradient known to the receiver device, the method comprising: receiving a chirp signal having a first gradient g; generating a reference chirp signal having a second gradient g?, wherein the second gradient g? differs from the first gradient g by a fixed value v; multiplying the reference chirp signal and the received chirp signal so as to form a mixed chirp signal; and detecting the received chirp signal by correlating the mixed chirp signal with a fixed gradient correlating chirp signal.

Abstract: A transmitter configured to communicate a data chirp signal to a receiver, the chirp signal comprising at least one symbol, each symbol comprising one or more identical chirps, each symbol having a different gradient to another symbol in the chirp signal, each chirp encoding a symbol value, the transmitter comprising: an address encoding module configured to encode an address associated with the communication via the sequence of gradients of the symbols in the chirp signal; a data encoding module configured to encode data in the chirp signal via the symbol value of each chirp; and a transmitting module configured to transmit the data chirp signal to the receiver.

Abstract: Decreased capability for detection of communications signals by an adversary is provided by applying frequency hopping, frequency chirping, and direct sequence spreading to the signals. The frequency hopping and frequency chirping can be driven by pseudo random functions. The direct sequence spreading can use a pseudo random chip sequence.

Abstract: Systems and methods for building, transmitting, and receiving frame structures in power line communications (PLC) are described. Various techniques described herein provide a preamble design using one or more symbols based on a chirp signal that yields a low peak-to-average power ratio (PAPR). According to some techniques, the preamble may be constructed with one or more different types and/or number of symbols configured to identify a PLC domain operating in close physical proximity to another PLC domain. According to other techniques, one or more preamble symbols may be interspersed within a header portion of a PLC frame to facilitate estimation of a frame boundary and/or sampling frequency offset, for example, in the presence of impulsive noise. According to yet other techniques, a PLC detector may be capable of receiving and decoding two or more types of PLC frames (e.g., using different PLC standards).

Abstract: A surface acoustic wave (SAW) expander based transmitter and correlator based receiver comprises SAW devices that perform expander or correlator functions based on the types of signals inputted to the SAW devices. The SAW devices incorporate chirp with adaptive interference and programmable coding capabilities. The SAW devices and method of operating the devices allow the implementation of very low power radios that overcome problems with temperature drift, lithography constraints and interference and jamming suffered by prior art implementations.

Abstract: An apparatus to facilitate wireless communication where one side of the link is designed for ultra-low power consumption. The apparatus comprises two types of transceivers: a full function transceiver (called the “Controller”) and a reduced function transceiver (called the “Terminal”), which are normally connected in a “star” network configuration (i.e. several Terminals communicating with one Controller). The Controller communicates with Terminals directly using chirp signals which contain the modulated data to be transmitted. The Terminal communicates with the Controller by re-transmitting “carrier” chirp signals which have been sent to it by the Controller. In this way the Terminal does not generate any of its own RF signals, thereby reducing its power consumption. The Terminals may not communicate directly with each other, only indirectly through the Controller.

Abstract: A network device for cancelling spurs without affecting an incoming signal. The network device includes an estimator for estimating amplitude and phase of a spur over a predetermined period of time. The network device also includes processing means for freezing further estimation of the amplitude and phase of the spur, for cancelling for an estimated spur and for allowing incoming packets. The network device further includes subtracting means for subtracting the estimated spur from an incoming packet. The estimated spur is subtracted from the incoming packet without affecting incoming signals that are not part of the estimated spur.

Abstract: Methods and systems for sending a broadcast message in frequency hopping and other systems. Instead of sending a complete message separately to each device, a relatively small packet or “chirp” is sent. These chirps are either targeted at known devices or sent in a manner to sweep the RF band. Devices that hear the chirps get information about the channel and/or time that the broadcast data will be sent. These devices then listen for the broadcast data as instructed, e.g., at the specified time on the specified channel. A system may alternatively, or in addition, use a scheduled hopping sequence break as a broadcast moment. Such a broadcast moment can be scheduled to periodically interrupt the node hopping sequences so that, at such times, many or all nodes are scheduled to be on the same channel for potential broadcasts.

Abstract: A communications system includes a modulator for generating a chirp signal aimed at spreading the frequency spectrum of an information signal over a specified spectral bandwidth of a communications channel. The chirp signal has initial and final instantaneous frequency. The chirp signal is controlled from an in-phase control signal and a quadrature-phase control signal to have, in a complex plane, constant amplitude and instantaneous phase. The instantaneous frequency is defined by the speed the instantaneous phase is changed in the complex plane by the in-phase and quadrature-phase control signals; the instantaneous frequency is linearly changed between initial and instantaneous frequencies over the whole duration of the chirp signal; the initial and final instantaneous phases of the chirp signal are identical.

Abstract: A phase component of a nonlinear frequency modulated (NLFM) chirp radar pulse can be produced by performing digital integration operations over a time interval defined by the pulse width. Each digital integration operation includes applying to a respectively corresponding input parameter value a respectively corresponding number of instances of digital integration.

Abstract: A cellular communication system employs a plurality of bandwidths. The cellular communication system comprises a plurality of base stations (101, 103) each of which transmits a reference signal comprising a Generalised Chirp-Like, GCL, sequence. The length of the GCL sequence is dependent on the bandwidth employed by the base station (101, 103). A sequence generator (105) provides a first subset of GCL sequences for a first bandwidth selected from a set of possible GCL sequences for the first bandwidth in response to properties of a sub-sequence of GCL sequences. The sub-sequence has a length corresponding to a different bandwidth. Sequence processors (107, 109) select GCL sequences for base stations (101, 103) employing the first bandwidth from the first subset of GCL sequences. The invention exploits characteristics of GCL sequences to enable, facilitate or improve multiple bandwidth operation.

Abstract: A multi-mode transmitter (301) is adapted to modulate a data packet (200) communicated by a wireless communications signal. The data packet includes a packet header comprising a preamble (201) and a start of frame delimiter (202), and a data payload comprising a payload data length portion (203) and a payload portion (204). The packet header is modulated with a spread spectrum technique. When transmitting a data payload in one mode, the data payload is also modulated with the spread spectrum technique. When transmitting a data payload in another mode, the data payload is modulated with a non-spread spectrum technique.

Abstract: A base station configured to communicate with a mobile station includes a controlling-information transmitting unit and a receiving unit. The controlling-information transmitting unit is configured to transmit to the mobile station as a set of controlling information, an information set indicating an environment of a cell which is resided by the mobile station, or an information set indicating power of interference from surrounding cells, or an information set indicating a condition of propagation channel. The receiving unit is configured to receive a signal transmitted from the mobile station, based on said set of controlling information, via a variably-controlling process of a spreading factor and a number of chip repetitions.

Abstract: Disclosed is a method and an apparatus for channel estimation regarding electromagnetic wave multi-path characteristics between a sender and a receiver by using a chirp signal.

Abstract: A communications system permits bandwidth configurability using a linear frequency modulated (LFM) waveform for transmitter/receiver synchronization. The system permits enhancement of MIL-STD-1553 data buses, and is likewise applicable to any bandwidth-configurable modem.

Abstract: An apparatus and technique for measuring and coping with interfering signals in a wireless communications system. The apparatus and technique rapidly and regularly measures the signals present in the wireless communication system's band of operation. The apparatus and technique then makes this information available to all the transceivers on the network, so that each transceiver has information the interference other transceivers see, and the system can make intelligent decisions about radio transmission parameters to optimize the network performance.

Abstract: Aspects of a method and system for a flexible automatic frequency control (AFC) design supporting transmit diversity are presented. Aspects of the system may include one or more circuits that enable computation of at least one frequency error value based on one or more previous computed frequency error values, current received symbols, and/or corresponding previously received symbols. A weighted sum may be computed from a plurality of computed frequency error values. A current demodulation frequency may be adjusted based on the computed weighted sum. The adjusted demodulation frequency may be utilized for receiving one or more subsequent symbols.