Abstract: A sequence generation method for allowing a reception end to effectively detect a sequence used for a specific channel of an OFDM communication system, and a signal transmission/reception method using the same are disclosed. During the sequence generation, an index is selected from among the index set having the conjugate symmetry property between indexes, and a specific part corresponding to the frequency “0” is omitted from a transmitted signal. In addition, a reception end can calculate a cross-correlation value between a received (Rx) signal and each sequence using only one cross-correlation calculation based on the conjugate symmetry property.

Abstract: The present invention employs hierarchical modulation to simultaneously transmit information on different modulation layers using a carrier RF signal. Initially, first data to be transmitted is assigned to a first modulation layer and second data is assigned to a second modulation layer. In one embodiment of the present invention, the first and second data are assigned based on reliability criteria. The first and second modulation layers are hierarchical modulation layers of the carrier RF signal. Once assigned, the first data is transmitted using the first modulation layer of the carrier RF signal and the second data is transmitted using the second modulation layer of the carrier RF signal. In one embodiment of the present invention, information may be transmitted to one end user using one modulation layer, and information may be transmitted to a different end user using a different modulation layer.

Abstract: Procedures performed prior to convolutional interleaving of 8VSB digital television signals restrict the alphabet of symbols in novel methods of generating trellis-coded digital television signals that include more robust symbol coding using a restricted alphabet of symbols selected from a full 8VSB symbol alphabet consisting of ?7, ?5, ?3, ?1, +1, +3, +5 and +7 normalized modulation levels superposed on a background modulation level. Certain of these novel procedures generate pseudo-2VSB or P-2VSB robust symbol coding with a restricted alphabet of symbols consisting of ?7, ?5, +5 and +7 normalized modulation levels superposed on a background modulation level. Others of these novel procedures generate prescribed-coset-pattern-modulation or PCPM robust symbol coding intermixing two restricted alphabets of symbols according to a prescribed pattern. One of the two restricted alphabets of symbols used in PCPM consists of ?3, ?1, +5 and +7 normalized modulation levels superposed on a background modulation level.

Abstract: An arrangement and method for channel mapping in a UTRA TDD HSDPA wireless communication system by applying interleaving functions in first (530) and second (540) interleaving means to a bit sequence to produce symbols for mapping to physical channels, the first and second interleaving means being arranged to map symbols from respectively systematic and parity bits in a predetermined scheme, e.g., mapping symbols in a forward direction when a channel has an even index number, and in a reverse direction when a channel has an odd index number. The symbols may comprise bit-pairs, each of a systematic bit and parity bit. Systematic bits are preferably mapped to high reliability bit positions in TDD HSDPA, achieving a performance gain of between 0.2 dB and 0.5 dB. The forwards/reverse mapping allows a degree of interleaving that improves system performance in fading channels or channels disturbed by short time period noise or interference.

Abstract: In accordance with some embodiments, a communication system is described that comprises a soft-output detector configured to receive a transmit signal and output reliability information regarding the received signal. In accordance with such embodiments, the detector comprises a symbol combiner configured to operate in both a repetition mode and a non-repetition mode, wherein repetition mode comprises receiving a plurality of signals for the transmit signal.

Abstract: A method of transmitting data that includes controlling generation of bit sequences to adjust an occupation rate occupied with predetermined bits included in a first data block, which is obtained by encoding first data in a first encoding process, to be equal or closer to an occupation rate occupied with predetermined bits included in a second data block, which is obtained by encoding second data in a second encoding process, in regard to first bit positions of the bit sequences generated using bits included in the first and second data blocks; and performing multi-level modulation for transmission based on the generated bit sequences.

Abstract: A transmitting apparatus, that includes a means for generating bit sequences to adjust an occupation rate occupied with predetermined bits included in a first data block, which is obtained by encoding first data in a first encoding process, to be equal or closer to an occupation rate occupied with predetermined bits included in a second data block, which is obtained by encoding second data in a second encoding process, in regard to first bit positions of the bit sequences generated using bits included in the first and second data blocks and a modulator for performing multi-level modulation for transmission based on the generated bit sequences.

Abstract: The Peak-to-Average Power Ratio in an OFDM transmission system is reduced based on a complementary parity coding in which the coding rules are derived from an appropriate auto-correlation property of transmitted symbol sequences.

Abstract: A multi-carrier spread spectrum device using cyclic shift orthogonal keying includes: a modulation unit for receiving a first part of data bits and transforming the first part of data bits to a modulation symbol di by modulation; a cyclic-shift unit for receiving a base code c(0) and a second part of data bits, and performing a cyclic-shift to the base code c(0) in accordance with the second part of data bits to generate a CSOK symbol c(mi); and a multiplier for multiplying the modulation symbol di by the CSOK symbol c(mi) to generate a spread spectrum signal ci.

Abstract: A method for implementation of error correction decoding of quadrature layered modulation QLM communications. A bound on communications capacity derived using ideal QLM is approximated with QLM communications links which support data rates independent of the Shannon bound. Trellis symbol and bit demodulation algorithms recover QLM data symbols and bit algorithms offer computational efficiency at a cost of decisioning errors. Correlated bit decisioning error correction decoding and re-encoding can be implemented in a bit demodulation algorithm. Trellis demodulation and trellis decoding algorithms support parallel implementations, and concatenated implementations wherein the error correction decoding is implemented after the QLM demodulation. Concatenated implementation supports turbo decoding, MAP decoding, convolutional decoding, and block decoding by using the decisioning metrics available from QLM demodulation in place of generating the decisioning metrics directly from the detected symbol measurements.

Abstract: Signal properties of a signal section (106) comprising a training sequence are compared with corresponding signal properties of other signal sections (108, 110). At a too large discrepancy, co-sequence interference is concluded to be present. The used signal property can preferably be a signal-to-noise ratio measure or a signal statistics measure. If the existence of co-sequence interference (102) is concluded, measures can be taken to avoid such interference and to mitigate the effects of the interference. A method for mitigating effects of co-sequence interference in channel estimation comprises a joint detection and estimation procedure performed under constrictions assuming presence of co-sequence interference.

Abstract: Methods and apparatus for determining the starting points of redundancy version transmissions in a circular rate matching operation. At least one block of information bits to be transmitted are encoded to generate a plurality of coded bits, which are then segmented into a plurality of sub-blocks of coded bits. Each of the sub-blocks of coded bits is interleaved by using a certain interleaver. The interleaved coded bits of the plurality of sub-blocks are collected and filled into a circular buffer having a plurality of redundancy versions in the circular buffer, with each redundancy version corresponding to a starting bit index in the circular buffer. For each transmission, a subset of bits are selected from the circular buffer by selecting a redundancy version from among the plurality of redundancy version. The selected subset of bits are modulated by using a certain modulation scheme, and are transmitted via at least one antenna.

Abstract: The disclosed embodiments provide for methods and systems for transmitting a number of streams of modulation symbols by a multi-antenna transmitter. In one aspect, a method for transmitting a number of streams of modulation symbols by a multi-antenna transmitter includes the acts of transforming a first number of streams of symbols to a second number of streams of symbols, the first number being smaller than or to the second number; and transmitting the second number of streams of symbols by a transmitter having the second number of antennas.

Abstract: A method for receiving a broadcasting signal and a broadcasting signal receiver are disclosed. Even when a cell is changed while an emergency alert is output, the emergency alert can be continuously output using emergency alert table information included in the broadcasting signal and channel information of the cell. The emergency alert table information may include a cell identifier and the channel information of the cell may include virtual channel information of the cell.

Abstract: A method of transmitting data including controlling generation of bit sequences to adjust an occupation rate occupied with predetermined bits included in a first data block, which is obtained by encoding first data, to be closer to an occupation rate occupied with predetermined bits included in a second data block, which is obtained by encoding second data. With regard to first bit positions of the predetermined bits, the first bit positions being distinguished from second bit positions based on an error tolerance resulting from a correspondence to a signal point on a phase plane. Wherein a sum of a number of the predetermined bits included in the first data block and the predetermined bits included in the second data block is less than a total number of the first bit positions. Also including performing multi-level modulation for transmission based on the generated bit sequences.

Abstract: In difference coding, each of a first to M-th channel signals is divided into frames and independent energy of every channel signal and difference energy of difference signals between all channel signals are calculated for each frame. In ascending order of energy, if a signal corresponding to an energy value is independent signal, it is determined that independent coding should be used for the signal. If the signal is a difference signal and the type of coding for one of channel signals has been determined, it is determined that the other should be difference-coded using the former channel signal as a reference signal. If the type of coding for neither of the channel signals has been determined, it is determined that one of them should be independently coded and the other should be difference-coded using the former channel signal as a reference signal.

Abstract: The present invention relates to a method for searching a solution point of maximum-likelihood detection. The solution point locates at a symbol constellation. The method includes the following steps: determining a central point and a norm by a zero-forcing detection method; determining a searching range according to the central point and the norm; determining at least one qualified solution point according to the searching range; and determining the solution point of maximum-likelihood detection from the qualified solution points.

Abstract: A data transmitting apparatus generates, by using predetermined first key information and information data, a multi-level signal in which a signal level changes so as to be approximately random numbers, and converts the multi-level signal into a modulated signal, in a predetermined modulation method and transfer the same. A data receiving apparatus demodulates the modulated signal so as to be converted into a multi-level signal, and reproduces information data from the multi-level signal, using second key information which has the same content as first key information used by the data transmitting apparatus.

Abstract: A data communication apparatus which improves security against eavesdropping is provided for secret communication using Y-00 protocol. In a data transmitting apparatus 101, a multi-level code generation section 111 generates, based on key information 11, a multi-level code sequence 12 in which a signal level changes so as to be approximately random numbers. A multi-level processing section 112 generates a multi-level signal 13 having a plurality of levels each corresponding to a combination between information data 10 and the multi-level code sequence 12. A level conversion section 113 divides the plurality of levels of the multi-level signal 13 into several groups, and allocates one level of a converted multi-level signal 21 to a plurality of levels included in each of the several groups in an overlapped manner. The level conversion section 113 then converts the multi-level signal 13 into the converted multi-level signal 21.

Abstract: When a receiver (200) receives a signal transmitted from a transmitter, an A/D converter (204) converts the signal into a digital signal having two or more levels by A/D conversion. A zero-level detector (207) converts the signal into a two-level digital signal of positive and negative levels. The converted signals are subjected to spectrum despreading by correlators (206, 208), respectively. Whichever signal has a higher intensity is selected by absolute value detectors (209, 210), a comparator (211), and a switch (212). A decoder (213) decodes the selected signal. In a receiving state where the zero-level detector (207) is selected, the transmitter transmits the transmission signal after the signal is converted into a two-level signal. In a receiving state where the A/D converter (204) is selected, the transmitter transmits the transmission signal after the signal is converted into a signal having two or more levels.

Abstract: The present invention concerns a sphere decoder for maximum likelihood receiver intended to receive M-PPM-M?-PAM symbols at M modulation positions and at M? amplitude levels from a plurality P of sources. The sphere decoder uses a Schnorr-Euchner type enumeration adapted to classify the points of a multidimensional PPM-PAM modulation.

Abstract: The present invention relates in general to transferring the envelope information of a polar modulated signal to a varying pulsewidth signal, while the phase modulation is direct transferred to the phase modulation of this PWM signal. Accordingly, the resultant signal is a PWM-PPM-signal. Such a signal can efficiently amplified by use of switching amplifying stages. By the present invention four pre-distorted baseband signals are applied basically to 4 linear RF mixers and a two adders, which are, the only needed external RF building blocks to build the modulator according to the invention. That is, the basic idea of the invention resides in the way of modulation of the four baseband signals and the way of combining of the RF modulated signals.

Abstract: A method for receiving a broadcasting signal and a broadcasting signal receiver are disclosed. Even when a cell is changed while an emergency alert is output, the emergency alert can be continuously output using emergency alert table information included in the broadcasting signal and channel information of the cell. The emergency alert table information may include a cell identifier and the channel information of the cell may include virtual channel information of the cell.

Abstract: A reception quality notifying method improves upstream-line throughput by reducing the data amount of reception quality data of downstream multicarrier signals to be transmitted in the upstream line. A low-power consumption base station apparatus and a wireless communication terminal apparatus may employ the reception quality notifying method. When a wireless communication terminal apparatus receives a downstream multicarrier signal and then notifies a base station apparatus of a subcarrier having a desirable reception quality for the downstream multicarrier signal, the wireless communication terminal apparatus produces reception quality data of a plurality of formats, then selects, from among the produced reception quality data, one having the lowest data mount. The selected reception quality data is transmitted to the base station apparatus by use of an upstream multicarrier signal subcarrier designated by the base station apparatus.

Abstract: A transmitting apparatus comprising circuitry operable to generate a plurality of bit sequences using bits included in a first data block and a second data block, circuitry operable to control the plurality of bit sequences to correspond to a signal point on the phase plane, comprising a bit sequence generating unit operable to control the generation of the bit sequences to adjust an occupation rate occupied with predetermined bits included in the first data block to be closer to an occupation rate occupied with predetermined bits included in the second data block in regard to bit positions of the predetermined bits, based on an error tolerance of the respective bit sequences generated resulting from the correspondence to a signal point on the phase plane, and circuitry operable to transmit the signals obtained by multi-level modulations in accordance with each signal point.

Abstract: A method of feeding back channel information in an OFDM or OFDMA radio communications system is disclosed, in which a transmitting side instructs a region for measuring a downlink channel status and in which a receiving side feeds back the channel information to the transmitting side. The present invention includes the steps of transmitting instruction information instructing at least one region of at least two regions within a data frame as a signal measurement region to a receiving side and receiving the channel information estimated by a signal included in the signal measurement region instructed by the instruction information from the receiving side.

Abstract: A channel structure that can efficiently transmit more data control bits, e.g., required by future wireless communication systems, yet achieve sufficient detection and false alarm performance uses tail-biting convolutional coding and Cyclical Redundancy Check (CRC). In certain implementations, symbol repetition, interleaving and/or scrambling can also be included. Also, depending on the implementation, modulation schemes such as Bi-Phase Shift Keying (BPSK), Quadrature Phase Shift Keying (QPSK) or Quadrature Amplitude Modulation (QAM) can be used in conjunction with the other coding techniques.

Abstract: Digital signal processing based methods and systems for receiving electrical and/or optical data signals include electrical receivers, optical receivers, parallel receivers, multi-channel receivers, timing recovery schemes, and, without limitation, equalization schemes. The present invention is implemented as a single path receiver. Alternatively, the present invention is implemented as a multi-path parallel receiver in which an analog-to-digital converter (“ADC”) and/or a digital signal processor (“DSP”) are implemented with parallel paths that operate at lower rates than the received data signal.

Abstract: A multilevel LINC transmitter. The multilevel LINC transmitter comprises a multilevel signal component separator, a phase modulator block, a mixer block, an up-converter block, a predistorter and an RF block. The multilevel signal component separator comprises a multilevel scaler and converts an input signal to phase signals. The phase modulator block and the predistorter are coupled to the multilevel signal component separator. The mixer block is coupled to the phase modulator block and the predistorter. The up-converter block is coupled to the mixer block. The RF block comprises a plurality of power amplifiers coupled to the up-converter block and a power combiner coupled to the power amplifiers.

Abstract: Various aspects of a method for minimum mean square error soft interference cancellation (MMSE-SIC) based sub-optimal maximum likelihood (ML) detection for a multiple input multiple output (MIMO) wireless system may comprise selecting at least one constellation point in a constellation map based on at least one of a plurality of received symbols. A number of the at least one constellation point may be less than or equal to a number of previously selected constellation points in a previous constellation map. At least one of the plurality of received symbols may be decoded based on the selected at least one constellation point.

Abstract: A wireless communication receiving device includes an initializing section for obtaining a temporary solution from a transmission route estimation value and a reception signal, a solution candidate calculating section for obtaining a solution candidate for each dimension existing inside a search area around the temporary solution, a solution candidate selecting section for deleting a solution candidate a cumulative distance of which is large when the number of solution candidates exceeds a specified resource number, a distance calculating section for obtaining a partial distance between the temporary solution and the solution candidate for each dimension, and a cumulative distance of the obtained partial distances, and a distance comparing section.

Abstract: A device and method for effectively judging a communication quality in a communication system and a program used for the judgment. A communication device generates a four-value FSK symbol by adding a redundant bit to a bit of the most important part of encoded audio data. The symbol containing the redundant bit is set so that the symbol value is the maximum value of the minimum value of the four values which may be obtained. A reception device R receives the FSK modulation wave, restores the symbol, counts the number of redundant bits contained in the restored symbol and having incorrect values, decides whether to perform a bad frame masking process and what kind of bad frame masking process is to be performed, and executes the decided process. Thus, it is possible to accurately or rapidly judge the communication quality with a simple configuration.

Abstract: A wireless communication device that includes more than two antennas considers only two of those antennas for use in receiving any particular wireless packet. During reception of an initial portion of a wireless packet, a quality metric may be measured for each of the two antennas being considered. One of the two antennas may then be selected to receive a payload portion of the wireless packet based on the measured metrics. In at least one embodiment, a different pair of antennas is considered for each successive received packet.

Abstract: A non-linear post-processor for estimating at least one source of signal-dependent noise is disclosed. The post processor may receive a set of preliminary decisions from a sub-optimal detector along with the sampled data signal. The post-processor may then compute the transition jitter and white noise associated with each preliminary decision in the set and assign a cost metric to each decision based on the total signal noise. The post-processor may output the decision with the lowest cost metric as the final decision of the detector.

Abstract: A communication system (10) using hierarchical modulation includes at least one satellite (12 & 13) transmitting a data stream and a hierarchical modulated data stream, and at least one terrestrial station (16) transmitting the data stream and the hierarchical modulated data stream. The communication system can further include at least one receiver (18) for demodulating and combining the data stream from at least one satellite and from at least one terrestrial station and for hierarchically demodulating and combining the hierarchical modulated data stream from at least one satellite and the hierarchical modulated data stream from at least one terrestrial station. The terrestrial station can be a terrestrial repeater repeating the data stream and the hierarchical data stream from at least one satellite. The system can also include an uplink (11) having a hierarchical modulator for modulating both the data stream and the hierarchical data stream.

Abstract: A radio transmitting apparatus and the like for improving the reception error rate characteristic. In this apparatus, a data modulating part (121) modulates a data signal to provide a modulated symbol. A Q-inverting part (125) generates a symbol that corresponds to the modulated symbol provided by the data modulating part (121) and that, when combined with the modulated symbol, becomes a signal having a particular value. A multiplexing part (110) multiplexes the modulated symbol provided by the data modulating part (121) with the corresponding symbol generated by the Q-inverting part (125) to provide a multiplexed signal.

Abstract: A multicarrier base station communicates with subscriber stations of different bandwidth profiles by allocating time slots in downlink and uplink frames and subcarriers of a single multicarrier communication channel to various bandwidth subchannels.

Abstract: In one embodiment a wireless communication device is provided that: acquires a phase rotation angle in the propagation channel which phase rotation angle is contained in a received symbol and that performs rotation compensation of the acquired phase rotation angle for the received symbol; generates a coordinate value of the respective I, Q axis in the signal constellation on which the information of the respective reference signal point is set; for the respective transmission bit, obtains respective probabilities that the transmission bit is 0 and 1 by making a distance determination of the distance between the received symbol after the rotation compensation and the respective reference signal level on only one of the I and Q axes; and makes a likelihood determination of the bit value of the respective transmission bit in accordance with a probability value obtained.

Abstract: Embodiments of the present invention provide a method, apparatus and system of decoding spatially multiplexed signals. In some demonstrative embodiments the method may include, for example, determining one or more hypothetical values of a transmitted signal of a set of transmitted signals based on one or more respective sets of hypothetical values assigned to a subset of the set of transmitted signals. Other embodiments are described and claimed.

Abstract: Methods and systems provide an efficient power save mode for multi carrier modems, such as DMT based ADSL and VDSL modems. Fast transitions from power save mode to full operational mode occur, without the overhead of transmitting large quantities of configuration information between the transmitter and receiver. Signal constellation size changes occurring while operating in power save mode to continue to apply once full operational mode is resumed. Multiple power save modes are enabled, each having a different level of power dissipation and crosstalk, both far end crosstalk and near end crosstalk. Power dissipation and crosstalk can thus be graduated on a line, according to a user-requested bit rate.

Abstract: An wireless terminal includes a demodulating unit which comprises an FV (fading vector) estimating unit for receiving a CPICH spread/demodulated signal to output an FV signal with a reduced noise ratio; a phase synchronization unit for multiplying a PDSCH spread/demodulated signal with a complex conjugate of the FV signal to correct the phase offset of the PDSCH I and Q signals to send the resulting PDSCH I and Q signals to a multi-level QAM amplitude synchronization detection unit and to an amplitude demodulating unit; a first-quadrant transformation unit for collecting the second to fourth quadrant signals of the phase-synchronized PDSCH I and Q signals; and a threshold value detecting unit for calculating a multi-level QAM threshold value from the first quadrant signals and the FV signals to send the threshold signal to an amplitude demodulating unit. The amplitude demodulating unit effects amplitude demodulation to output multi-level QAM demodulated signals.

Abstract: An arrangement and method for channel mapping in a UTRA TDD HSDPA wireless communication system by applying interleaving functions in first (530) and second (540) interleaving means to a bit sequence to produce symbols for mapping to physical channels, the first and second interleaving means being arranged to map symbols from respectively systematic and parity bits in a predetermined scheme, e.g., mapping symbols in a forward direction when a channel has an even index number, and in a reverse direction when a channel has an odd index number. The symbols may comprise bit-pairs, each of a systematic bit and parity bit. Systematic bits are preferably mapped to high reliability bit positions in TDD HSDPA, achieving a performance gain of between 0.2 dB and 0.5 dB. The forwards/reverse mapping allows a degree of interleaving that improves system performance in fading channels or channels disturbed by short time period noise or interference.

Abstract: A demodulator recovers a transmitted symbol represented by a received quadrature amplitude modulation (QAM) signal. Such a demodulator may include: a QAM-decoding block operable to map a received signal vector onto a constellation so as to yield a first symbol, and identify a next-most probable second symbol based upon the signal vector; and a selection unit operable to select, among the first and second symbols, the one having the lower error content as corresponding to the transmitted symbol. A corresponding method may include similar steps.

Abstract: A system and method for synchronising data for use in a powerline communications network. Data containing a plurality of symbols is received and a predetermined number of data samples are used to calculate an alignment error associated with the data samples. The alignment error represents the extent to which the data samples are aligned with one of the symbols. The alignment error is then used to determine the extent to which the alignment position should be changed so as to provide substantial alignment with a subsequent symbol.

Abstract: A method and apparatus for encoding data for wireless transmission. The invention includes multi-level coding in which data is partitioned between two encoders, one for encoding Most Significant Bits (MSBs) and the other for encoding Least Significant Bits (LSBs). By partition bits separately for the MSBs and LSBs, the complexity of the decoder may be reduced. The MSBs and LSBs are interleaved such that each MSB is a function of just one LSB, simplifying branch metric selection during Viterbi decoding. This also allows parallel de-interleaving by the receiver, which reduces the interleaving latency of the receiver. A block interleaver jointly optimizes the symbol hamming distance of the symbols and the bit hamming distance of each constituent encoder for the MSBs and LSBs.

Abstract: The transmission system is backward compatible with a former transmission system (DVB-T), enabling a receiver of the former system to receive signals transmitted by a transmitter of the new transmission system. A new modulation is used to transmit additional information bits corresponding to a new service. The new modulation is specified by a combination of the former modulation with a new-built over modulation.

Abstract: A method for configuring a multiple input multiple output (MIMO) wireless communication begins by generating a plurality of preambles for a plurality of transmit antennas. Each of the plurality of preambles includes a carrier detection sequence at a legacy transmit rate, a first channel sounding at the legacy transmit rate, a signal field at the legacy transmit rate, and Z?1 channel soundings at a MIMO transmit rate, where L corresponds to a number of channel soundings. The method continues by simultaneously transmitting the plurality of preambles via the plurality of transmit antennas.

Abstract: An OFDM (Orthogonal Frequency Division Multiplexing) system may utilize pilot symbol structures including two or more pilot symbols with pilot information on alternate tones. The pilot information in one symbol is transmitted on mirror tones in another of the symbols. The pilot symbol structure may include a copy of one of the pilot symbols to aid in frequency offset estimation.

Abstract: A digital broadcasting receiver, a driving method, and a self-diagnosis method thereof, are provided. The digital broadcasting receiver includes: a digital demodulator for demodulating a digital broadcasting signal; a lock detector for detecting lock signals from the digital demodulator; and a lock processor for controlling the digital demodulator according to the detected lock signal.

Abstract: A method of shaping an orthogonal frequency division multiplexing (OFDM) signal spectrum is disclosed. The method comprises receiving an input signal that has a frequency spectrum that includes a frequency peak, and limiting the amplitude of the frequency peak to a predetermined clip level. An orthogonal frequency division multiplexing (OFDM) transmitter is disclosed. The OFDM transmitter comprises an input interface configured to receive an input signal that includes a frequency spectrum that includes a frequency peak, and a processor coupled to the input interface, configured to limit the amplitude of the frequency peak to a predetermined clip level.