Abstract: An adaptive, reduced-complexity soft-output maximum-likelihood detector that is operable to process data by adaptively selecting a processing scheme based on a determination of signal quality. The signal quality is derived as a function of the noise, the modulation format, the channel (the communication environment), the transmit signal power and the receive signal power. If the signal quality is low, the signal is processed using a maximum likelihood detector. If, however, the signal quality is high, a simpler sub-optimal detector is used. By estimating the signal quality and choosing an appropriate detection method, the present invention ensures accurate detection of incoming data signals in a MIMO communication system while maintaining the highest possible processing speed.

Abstract: A data processing apparatus maps input symbols to be communicated onto a predetermined number of carrier signals of an Orthogonal Frequency Division Multiplexed (OFDM) symbol. The data processor includes an interleaver memory which reads-in the predetermined number of data symbols for mapping onto the OFDM carrier signals. The interleaver memory reads-out the data symbols on to the OFDM carriers to effect the mapping, the read-out being in a different order than the read-in, and the order being determined from a set of addresses. The set of addresses are generated from an address generator. The address generator includes a linear feedback shift register and a permutation circuit.

Abstract: An acquisition module includes a coherent correlator configured to receive a transmission having a pilot signal and correlate the received transmission with a local copy of the pilot signal to produce a first output, a delayed correlator configured to delay the first output and correlate the first output with the delayed first output to produce a second output, and a detector configured to detect the pilot signal in the transmission based on the second output.

Abstract: A first signal generation section 11 generates a baseband modulation signal for an ASK modulation scheme from transmission data. A second signal generation section 12 generates a pair of baseband modulation signals for a non-ASK modulation scheme from transmission data. When performing non-ASK modulation, a switch 15 connects between an input terminal d and an output terminal and outputs the baseband modulation signals based on the non-ASK modulation. When performing ASK modulation such that the transmission power ratio of the ASK modulation scheme to the non-ASK modulation scheme is a factor of 1, a switch 14 connects between an input terminal b and an output terminal and the switch 15 connects between an input terminal c and the output terminal. When performing ASK modulation such that the transmission power ratio is a factor of 2, the switch 14 connects between an input terminal a and the output terminal and the switch 15 connects between the input terminal c and the output terminal.

Abstract: Techniques for reducing peak-to-average power in multicarrier transmitters employ peak cancellation with subcarriers that are impaired by existing channel conditions. The use of Carrier Interferometry (CI) coding further improves the effectiveness of peak reduction. CI coding can also be impressed onto pulse sequences in the time domain, which enhances spectral selection and facilitates peak-power control.

Abstract: A communication device for receiving and transmitting OFDM signals in a wireless communication system, in which each OFDM signal is composed of a plurality of subcarrier signals each being assigned to a respective transmission channel of said communication system, including a diversity antenna unit including a plurality of antenna elements; an examination unit adapted for examining, individually for each antenna element, at least one subcarrier signal of an OFDM reception signal received by a respective one of the antenna elements and for gaining, from the result of such subcarrier signal examination, attenuation information on attenuation properties of at least some of the transmission channels associated to the respective antenna element; and an amplitude adjustment unit adapted for adjusting, individually for each antenna element, the amplitude of at least one subcarrier signal of an OFDM transmission signal to be transmitted from a respective one of said antenna elements.

Abstract: A modulation and demodulation system is provided. The system uses n sub-carrier frequencies and an oversampling positive integer and includes a modulation circuit and a demodulation circuit. The modulation circuit includes a modulation ROM that stores columns of elements independently in a modulation ROM matrix. The demodulation circuit includes 2n numbers of a ROM1 that stores elements of a combined matrix. The combined matrix is generated by combining a number of inverse matrices where the inverse matrices are generated from the modulation ROM.

Abstract: An apparatus for generating a preamble sequence in an orthogonal frequency division multiplexing (OFDM) communication system using A subcarriers in a frequency domain. A preamble sequence generator generates a length?M+N+k preamble sequence, where M+N+k is less than A, by combining a length?N Golay complementary sequence with a length?M Golay complementary sequence. An inverse fast Fourier transform (IFFT) processor assigns elements constituting the preamble sequence to the M+N+k subcarriers among the A subcarriers on a one-to-one mapping basis, assigns null data to remaining subcarriers excluding the M+N+k subcarriers from the A subcarriers, and then IFFT-transforms the assigned result into time-domain data.

Abstract: A method, apparatus, and system allowing terminal hosted group activities is provided, whereby proximity and non-proximity connections between a hosting mobile terminal and participating terminals enables group hosting activity. The hosting mobile terminal guides information flow between itself, the participating terminals, and optionally, with network servers that may assist the hosting mobile terminal. The hosting mobile terminal provides group management, profiling, downloading, presence, gaming, payment/charging, and authentication functions either in terminal only mode, or alternatively in conjunction with server assistance.

Abstract: An optical disk playback apparatus for playing back or reproducing main data and its associated sub-code which are read from an optical recording medium comprises an interleave RAM for storing the main data. The optical disk playback apparatus performs a predefined synchronization protection on synchronization information included in the sub-code to generate a sub-code synchronization signal which is written into an empty area of the interleave RAM, and manages the addresses with a FIFO area in a manner similar to the main data, thereby causing the read sub-code synchronization signal to function in synchronization with the main data.

Abstract: A method for estimating a transmission channel from a multicarrier signal transmitted through said transmission channel, comprising real pilot symbols and so-called pure imaginary pilot symbols, consists in selecting one or several values zk of the received signal corresponding respectively to one or several real pilot symbols, and one or several values zl of the received signal corresponding respectively to one or several pure imaginary pilot symbols. The pilot symbols are sufficiently close both in frequency and in time such that it can be assumed that the fading of the signal through the transmission channel has a complex value ? substantially identical for the symbols. An estimated value {circumflex over (?)} of ? for the pilot symbols concerned is then determined by minimizing a least square equation involving the values zk and the values zl.

Abstract: The invention concerns a method for estimating the transfer function of a multicarrier signal transmission channel consisting of a temporal succession of symbols of a set of data elements, each of the data elements modulating a carrier frequency of the signal, the data elements comprising pilots and so-called informative data elements. The invention is characterized in that said method comprises: a step which consists in determining a set of two-dimensional discrete prolate spheroidal sequences (DPSS); a step which consists in writing the transfer function in the form of a combination of at least some of the two-dimensional discrete prolate spheroidal sequences (DPSS); a step which consists in time-based and frequency-based two-dimensional interpolation of at least some of the coefficients of the combination, so as to obtain an estimation of the transfer function at any point of a time-frequency network.

Abstract: A communication system that can satisfactorily communicate with a mobile station by a transmitter and receiver of a simple arrangement wherein a plurality of carriers having different frequencies are transmitted simultaneously and data is transmitted on the basis of a phase difference between the carriers. Also, the carriers are multiplied with a predetermined time waveform and transmitted, so that a reception side receives data by use of a time waveform narrower than the above time waveform.

Abstract: A method of communicating across a channel includes receiving information having a known bandwidth and a known spectrum. The information is preferably in the form of a multicarrier modulated signal, e.g., a DMT signal. In one aspect, this information is received at a receiver having a reduced channel bandwidth. An aliasing spectrum can be calculated based on the known spectrum and the frequency difference between the known bandwidth and the reduced-channel bandwidth. The received information can then be modified based upon the aliasing function to compensate for alias distortion. For example, the received information can be modified by modifying the noise component or signal-to-noise ratio of the received information.

Abstract: A radio transmission signal consisting of signal frames that comprise a dynamic data part and a quasi-static data part according to the present invention is characterized in that the dynamic data part of a respective frame contains an indicator showing in which following frame the quasi-static data part of this respective frame will be repeated. Therewith, an alternative frequency of e.g. a digital shortwave signal like a DRM signal can easily and satisfactorily be checked before a fast seamless switching to this alternative frequency can be performed.

Abstract: In the method according to the invention for searching for the carrier frequency f of a mobile radio transmitter in a mobile radio receiver, two or more values e(k) of the spectral input power are measured at different discrete test frequencies fk, where fk<fk+1. The maximum e(kmax) of the values e(k) and of the associated test frequency fkmax is then searched for. An estimated value f?, which is characteristic of the sought carrier frequency f, can be determined from knowledge of the values of at least one value pair e(k1) and e(k2) where k1<kmax<k2, and of the specific test frequency fkmax.

Abstract: Techniques to determine a set of rates for a set of data streams to be transmitted in a multi-channel communication system. A group of transmission channels to be used for each data stream is initially identified. An equivalent system for each group is then defined to have an AWGN (or flat) channel and a spectral efficiency equal to the average spectral efficiency of the transmission channels in the group. A metric for each group is then derived based on the associated equivalent system, e.g., set to the SNR needed by the equivalent system to support the average spectral efficiency. A rate for each data stream is then determined based on the metric associated with the data stream. The rate is deemed to be supported by the communication system if the SNR required to support the data rate by the communication system is less than or equal to the metric.

Abstract: Techniques and apparatuses to determine a set of rates for a set of data streams to be transmitted in a multi-channel communication system. A group of transmission channels to be used for each data stream is initially identified. An equivalent system for each group is then defined to have an AWGN (or flat) channel and a spectral efficiency equal to the average spectral efficiency of the transmission channels in the group. A metric for each group is then derived based on the associated equivalent system, e.g., set to the SNR needed by the equivalent system to support the average spectral efficiency. A rate for each data stream is then determined based on the metric associated with the data stream. The rate is deemed to be supported by the communication system if the SNR required to support the data rate by the communication system is less than or equal to the metric.

Abstract: The transmission system of the present invention is designed to transmit a plurality of signals between the transmitter and the receiver using a plurality of carriers and comprises a radio link characteristics estimator 4 configured to estimate the characteristics of a radio link between the transmitter and the receiver and a carrier quantity determination unit 3 configured to determine the number of carriers according to the result of the estimate by the radio link characteristics estimator 4. The radio link characteristics estimator 4 estimates the characteristics according to an interval in delay time of multipath signals and the number of the multipath signals. The carrier quantity determination unit 3 determines fewer carriers when multipath interference is small, and determines more carriers when the multipath interference is great.

Abstract: A bit loading for a channel of a multi-carrier data communication system is generated. The bit loading has a target bit rate and satisfies predetermined performance criteria. When the channel is loaded according to the bit loading, a minimal number of sub-channels of the channel are active.

Abstract: The invention concerns a unit for sending from a base station to terminals in a telecommunications system, said unit comprising at least two sending channels or groups of sending channels adapted to send on a plurality of adjacent carrier frequencies, said channels being able to send in spatial diversity mode so that the same information may be sent by the channels or groups of channels on the same carrier frequency or frequencies. In this unit the channels or groups of channels use at least one common carrier frequency for sending in spatial diversity mode and at least one of the channels or groups of channels comprises at least one different frequency for sending without spatial diversity or with a lower degree of spatial diversity.

Abstract: The present invention provides a technique to reduce peak-to-average power ratio (PAR) of multi-carrier transmission systems. A non-empty subset of the subcarriers includes “PAR subcarriers.” The PAR subcarriers have constellations obtained by reducing a constellation that is higher than binary and invariant under multiplication by ?1, so that an element is in the reduced constellation if and only if its negative is not. In this way, only one bit per PAR subcarrier is used for PAR reduction. The technique addressed in this invention multiplies a subset of the PAR subcarriers by ?1 to reduce PAR at each multi-carrier symbol transmission. A method or apparatus is operated to select the subset of PAR subcarriers to be rotated. The receiver identifies the PAR subcarriers and estimates the subcarriers multiplied by ?1 according to the reduced constellations and the received samples.

Abstract: Disclosed is a communication system in which it is possible to detect a TFI (Transport Format Indicator) even if a TFCI (Transport Format Combination Indicator) cannot be decoded correctly. The system includes a transmitting apparatus which, when a transmission is made, encodes transmit data of each transport channel (TrCH) at a prescribed transmission time interval (TTI), partitions the encoded data at a frame period to obtain frame data of a prescribed bit length, multiplexes and transmits the frame data of each TrCH and transmits TFCI information that specifies the frame data length of each TrCH. The system includes a receiving apparatus for comparing, on a per-TrCH basis, the TFIs of a plurality of frames within a transmission time interval (TTI) conforming to the TrCH and, if TFIs differ, deciding the transport format (TFI) in this transmission time interval (TTI) by majority decision, etc.

Abstract: A method of modulating a multicarrier signal involves obtaining a set of 2M representative complex coefficients of transmitted data. 2LM linear combinations are calculated so as to leave 2M obtained complex coefficients. Coefficients of balancing used in these combinations represent a prototype function g(t). The 2LM coefficients are summed in given areas of memory. The 2LM memory sites represent 2L groups of M distinct partial sums. The transmitted samples are sent so as to gradually form M samples to transmit, in the memory sites, over a defined duration.

Abstract: This invention relates to a method and device for improving the reliability and performance of cellular telephones. In particular, this invention provides a method of transmitting two signals which are substantially identical over two different cellular networks. The transmitted signals are received by a receiving device and synchronized and combined into one combined signal. The invention also discloses a cellular telephone system that is able to transmit two substantially identical signals over two different cellular networks which are received by a telephone device capable of synchronizing and combining the signals into one combined signal.

Abstract: A radio frequency communication system utilizing a radiating transmission line for communicating data signals is disclosed. The data signals convey digital data to remotely located data devices, including computers, equipment control systems and digital video cameras. The data signals have a wide bandwidth of about 0.5 MHz to 32 MHz. In this way, the communication system creates a local area network by means of the radiating communication line. The communication system is intended to be used in environments where radio waves do not propagate well, such as in underground environments, and in particular mines. The communication system comprises at least one amplifier connected to the radiating transmission line for periodically amplifying the data signals by demodulating the data signals to recover the data contained therein and then modulating the recovered data into a regenerated radio frequency at a power level permitting transmission and radiation of the regenerated radio frequency data signal.

Abstract: A wireless sensor and control system includes wireless RF transmitter units and one or more receivers that communicate using more than one narrowband radio channel to provide increased reliability in the presence of unintentional radio interference. The output of a sensor transducer or closure of a switch contact can trigger transmissions at two or more narrowband carrier frequencies that are subsequently decoded by the receiver(s). The remote sensor data can then be passed to another system for processing and/or utilized to control remote devices. In accordance with one practical embodiment, the remote sensor data indicates the ingress or egress of monitored product inventory.

Abstract: A multi-carrier communications apparatus which communicates between a first station and a second station as a destination station using a reference signal used for estimating a state of a channel, the multi-carrier communications apparatus comprising a multi-carrier modulator which modulates data on a plurality of subcarriers, a transmission unit configured to transmit the reference signal together with the data modulated to the destination station every subcarrier, and a control unit configured to control a reference signal transmission pattern according to a given communication condition, the reference signal transmission pattern including a transmission interval of the reference signal transmitted by the transmission unit.

Abstract: An apparatus for and method of generating normalized soft decision information output from an inner decoder (i.e. equalizer) in a communications receiver. The invention is operative to normalize the soft decision information before it enters a soft outer decoder. The normalization is performed using a noise power estimate that is dynamically calculated in response to changing noise statistics on the channel. The normalized soft decision output is then applied to the soft outer decoder thus realizing maximum performance therefrom. The noise power estimate is derived from the training sequence and/or the data portion of the received signal. Both types of estimates are calculated. A binary or smoothly weighted average is calculated using both types of estimates. The weighting factor is determined based on one or more performance metrics, such as the Signal to Noise Ratio (SNR).

Abstract: The present invention is directed to apparatus and method for encoding and decoding data within a wireless network such that a MS preferably does not require multiple receivers to handle communications from BTSs with varying numbers of antennas. In embodiments of the present invention, a space-time matrix is utilized to encode the data streams being transmitted from a BTS such that a BTS with fewer antennas would simply have an encoding matrix with one or more of the columns or rows removed from the matrix. In this way, the MSs within the wireless network can be designed to decode with the use of only a single space-time encoding matrix, this space-time encoding matrix working for BTSs with various numbers of antennas.

Abstract: In the access control system, a code transmitter-end transceiver unit and a vehicle-end transceiver unit emit signals approximately synchronously on approximately the same carrier frequency. As a result of superimposition, a new code signal arises and its code information item is compared with an expected set point code information item. When there is correspondence, an enable signal for locking or unlocking or releasing the immobilizer is generated. The synchronous transmission/reception makes illegitimate monitoring more difficult.

Abstract: A method (600) and a base station controller (120) for enabling a quick repeat feature are described herein. The base station controller (120) monitors an operating parameter associated with a mobile station (160). The base station controller (120) detects a condition suggesting a potential for a transmission failure to the mobile station (160) based on the operating parameter. The base station controller (120) provides a plurality of transmissions of an operating message to the mobile station (160) in response to detection of the condition suggesting a potential for a transmission failure to the mobile station (160). The operating message includes operating information associated with communication between a base station (140) and the mobile station (160).

Abstract: A system and method for vector wireless radio communication (multiple modes or signal streams) between a first communication device and a second communication device using radio frequency (RF) communication techniques. At each communication device, signals are received at a plurality of antennas representing a plurality of modes simultaneously transmitted by the other communication device, wherein each mode is a signal stream. A transmit matrix is computed from signals received at the plurality of antennas. The transmit matrix distributes a plurality of modes among a plurality of antenna paths each associated with a corresponding one of the plurality of antennas of the first communication device, and is applied to the plurality of modes to be simultaneously transmitted from the plurality of antennas of one communication device to the other communication device.

Abstract: When channel-coded data is transmitted in a wireless communication system, coded data is divided into a plurality of bandwidths and the signal power is distributed to the bandwidths so that the communication channel capacity is increased. In addition, the transmission power is controlled on a time basis in such a way that the average power becomes larger when the channel quality is poorer so that the quality of each code word is stabilized. Alternatively, the coding rate is controlled in such a way that the data rate is decreased when the channel quality is poorer.

Abstract: A correlator for use in a timing recovery apparatus of a receiver in a multicarrier transmission system. The correlator locates the beginning of a data frame and initializes a pointer register with an address to a location within the receive signal buffer. Data is transferred to a signal converter from the receive signal buffer where the samples that are fed into the converter are determined by the address stored in the pointer register.

Abstract: Communication of a device by controlling a wire communication interface to receive a bit stream from an external device via a wire transmission line, controlling a radio communication interface to receive a bit stream from an external device via a radio transmission line, and controlling the wire communication interface to transfer the bit stream received by the wire communication interface to another external device via the wire transmission line and to transfer the bit stream received by the radio communication interface to another external device via the wire transmission line. Additionally, the wire communication interface may be controlled to transfer the bit stream to an external device via a wire transmission line using an isochronous transfer mode.

Abstract: In orthogonal frequency division modulation, use is made of the fact that the individual carriers which are transmitted on the principle of frequency multiplexing are orthogonal to one another. The modulation can then be carried out relatively simply using discrete Fourier transformation. Sicne the calculation of the discrete Fourier transformation involves a large number of multiplications, the bit data which are intended to be modulated onto the carriers are combined in each case to form a two-dimensional vector. The vector is supplied to a two-dimensional inverse Fourier transformation as the input variable. The number of multiplications required is thus reduced. The invention is particularly suitable for transmission of broadcast radio, television and mobile radio signals.

Abstract: A synchronization system within a dual antenna receiver employs two timing recovery loops each coupled to a different antenna input. The timing error computed within each timing recovery loop is differentiated by a high pass filter and compared to a predefined threshold indicating convergence. Both sampling rates are then synchronized utilizing the timing error from whichever loop converges first. If synchronization lock for the selected loop is lost, the other loop is selected to provide timing error to both loops.

Abstract: Techniques for transmitting and receiving multiple channels with block coding in a communication system are disclosed. In one aspect, a secondary broadcast channel is transmitted concurrently with parity information, encoded from a primary broadcast channel. In another aspect, a mobile station repurposes its receiving circuitry to receive one or more portions of the secondary broadcast channel after a sufficient portion of the primary broadcast channel is received without identified error. In another aspect, secondary broadcast channels associated with a plurality of primary broadcast channels are multiplexed onto a single secondary channel. Various other aspects are also presented. These aspects have the benefit of minimizing mobile station resources required to receive multiple broadcast channels, as well as reducing the complexity and channel resources required to transmit multiple broadcast channels.

Abstract: Devices having either wireless data communication capability or RFID tags can be located using dual function fixed devices which are distributed throughout a facility. The devices will identify those units with which they are communicating using a wireless radio data communications protocol and also identify items within the local area using RFID tags on the units.

Abstract: Systems and methods for appending cyclic prefixes to OFDM bursts while employing minimal additional memory and adding minimal latency are provided. This facilitates lower cost implementations of OFDM communication systems including systems that carry real time traffic such as telephony and video conferencing. The phases of frequency domain symbols are rotated prior to application of the IFFT so that cyclic prefix addition may be implemented as cyclic postfix addition. Cyclic postfix addition requires much less memory and imposes much less latency then cyclic prefix addition.

Abstract: A communication apparatus includes a correction value calculator for calculating a correction value for a received signal, a status determiner for determining a reception status relating to a reception of a plurality of carriers based on the correction value of the correction value calculator, a determination information inserter for inserting determination information in a transmission signal based on the determination of the status determiner, a transmission mode selector for selecting a transmission mode based on the determination information inserted in a transmission signal, a transmission mode information inserter for inserting, into a transmission signal, information relating to the transmission mode selected by the transmission mode selector, and a transmission mode determiner for determining the transmission mode based on the transmission mode information inserted in the transmission signal. Quality of communication is maintained without reducing a transmission rate by using a usable carrier only.

Abstract: A wireless sensor and control system includes wireless RF transmitter units and one or more receivers that communicate using more than one narrowband radio channel to provide increased reliability in the presence of unintentional radio interference. The output of a sensor transducer or closure of a switch contact can trigger transmissions at two or more narrowband carrier frequencies that are subsequently decoded by the receiver(s). The remote sensor data can then be passed to another system for processing and/or utilized to control remote devices. In accordance with one practical embodiment, the remote sensor data indicates the ingress or egress of monitored product inventory.

Abstract: A point to multipoint radio service is disclosed which enables a mobile telephone network subscriber to transmit data simultaneously to a plurality of public switched telephone network subscribers. According to the present invention, a plurality of calls originate from the mobile telephone network subscriber, modems in an interworking function device are allocated with respect to the calls, and then wire modems and traffic paths of the PSTN subscribers are established corresponding to the originating calls after the modem allocation.

Abstract: Vector orthogonal frequency division multiplexing (VOFDM) receiver correlation matrix processing using factorization. Efficient correlation matrix processing is used to combine multiple signals into a single combined signal. This single combined signal may be viewed as being a beam form soft decision. An efficient square root factorization system and method provides for computational resource savings while, at the same time, providing for greater precision of the overall computational results. By reducing intermediate variable calculation dynamic ranges, the overall calculation becomes more precise. Particularly within fixed-point arithmetic applications, a reduction in dynamic range of the intermediate variable calculations provides for a significant increase in final calculation precision.

Abstract: A method and apparatus for flow treatment and flow mapping of a broadcast/multicast service is disclosed. A base station provides flow treatment and mapping data to a packet data serving node during the establishment of a user traffic channel. The flow treatment and mapping data includes an IP multicast address and a service option parameter. A content server sends a broadcast packet flow to the packet data serving node via an IP network. Header compression for the packet flow is determined from the service option parameter. The packet flow is mapped to the appropriate user traffic channel using the IP multicast address.

Abstract: A method for increasing the interrogation range of an RF Tag in a radio communication system using RF Tags with multiple reflecting antenna elements. The reflecting antenna elements are predeterminately positioned, and preferably aligned, with respect to each other in the direction of expected incident RF radiation. The reflecting antenna elements are sequentially pulsed on and off such that while the first reflecting antenna element is in a signal reflecting operating state, the remaining reflecting antenna elements are in a substantially non-reflecting state, and when the second reflecting element is in a reflecting operating state, the remaining reflecting elements are in a non-reflecting state, etc. The sequential pulsing and predetermined fixed spacing between the reflector elements generates constructive interference between the reflected signals of the reflecting antenna elements which increases the power of the resulting reflected signal.

Abstract: An analog modulation technique where the message information is contained in the timing of phase reversal zero crossings in the transmitted signal. In the preferred implementation a bias signal is added to an information signal and the composite signal hard limited to produce a square wave. The square wave is used to switch the phase of a carrier signal so that phase reversals occur in correspondence with the change in polarities of the square wave. A demodulation technique is also disclosed.

Abstract: The time of arrival of a received signal with multipath components is precisely estimated using an optimal algorithm, such as Maximum Likelihood Estimation (MLE), after restricting the optimal algorithm's search space to one or more time intervals determined by preprocessing the received signal using a less computationally complex sub-optimal algorithm. This approach yields the accuracy benefits of optimal algorithm processing, while reducing aggregate computational complexity. Sub-optimal algorithms include but are not limited to correlation, MUSIC, and Signal-Eigen-Vector (SEV) processing. Iterative sub-optimal pre-processing of the received signal further refines the optimal algorithm search space, and, in some instances, may be used to resolve multipath time-of-arrival (TOA) with sufficient accuracy.

Abstract: An alternative frequency of e. g. a digital shortwave signal like a DRM signal can easily and satisfactorily be checked whether or not the same service is transmitted before a fast seamless switching to this alternative frequency can be performed. The inventive method to perform such a checking is characterized by a respective correlation of at least two sets of samples taken from the signal transmitted on the alternative frequency having a predetermined time relationship (&Dgr;tcorr) and a comparison of said respective correlation results, i.e. comparison of the time (t1) of occurance of a correlation peak included in a first correlation result with the time (t2) of occurance of a correlation peak included in a respective further correlation result, to verify that both services are the same when the time relationship (|t2 l -t1|) between said correlation peaks is the same as said predetermined time relationship (&Dgr;tcorr) of the at least two sets of samples.