Abstract: A method for receiving a downlink signal by user equipment in a wireless communication system that supports coordinated multiple-point transmission and reception (CoMP) according to one embodiment of the present invention includes receiving information regarding two candidate demodulation reference signal (DMRS) groups for generating a sequence of downlink demodulation reference signals; and generating a sequence of downlink demodulation reference signals using one of at least two candidate DMRS configuration parameter sets. Each of at least two candidate DMRS configuration parameter sets includes a cell identifier and a scrambling identifier. The scrambling identifier included in one of at least two candidate DMRS configuration parameter sets may be determined whether the two cell identifiers included respectively in at least two candidate DMRS configuration parameter sets are the same or not.

Abstract: An orthogonal frequency division multiplexing (OFDM) transmission system is provided which includes a data processing unit which generates a transmission signal using a plurality of tones including a reserved tone, a storage unit which stores Peak Reduction Kernel information according to the type of data symbol, and a compensation unit which retrieves the Peak Reduction Kernel information according to the type of data symbol from the storage unit and causes the retrieved information to be carried by the reserved tone included in the transmission signal. Therefore, a Peak-to-Average Power Ratio (PAPR) can be efficiently compensated.

Abstract: A relay communications system is described in which a base station is able to support both Frequency diversity R-PDCCH transmission and Frequency selective R-PDCCH transmission either within different cells, or within the same cell but not the same sub-frame or within the same cell and within the same sub-frame.

Abstract: A method and apparatus for transmitting a downlink reference signal in a wireless communication system supporting multiple antennas are discussed. A method for transmitting Channel State Information-Reference Signals (CSI-RSs) for eight or less antenna ports includes selecting one of a plurality of CSI-RS Resource Element (RE) groups defined on a data region of a downlink subframe and mapping CSI-RSs for the eight or less antenna ports to the selected CSI-RS RE group, and transmitting the downlink subframe in which the CSI-RSs for the eight or less antenna ports are mapped.

Abstract: A method for allocating resources in a mobile communication system is provided. The resource allocation method includes determining whether a transmission time of response information indicating presence/absence of an error in received data overlaps a transmission time of channel state information; and when the transmission times overlap each other, allocating, to the response information, a resource block for the channel state information, cyclic shift values in a frequency domain, and orthogonal sequences having orthogonality in a time domain.

Abstract: Aspects of embodiments relate to an optical wavelet transform (WT) or inverse wavelet transform (IWT) medium for implementing optical multiwavelet orthogonal Frequency Division Multiplexing (OFDM) or optical demultiplexing. In embodiments, the optical WT/IWT medium comprises a plurality of N waveguides for receiving in parallel a corresponding number of N modulated optical input signals ?1,MOD to ?N,MOD. Each waveguide comprises at least two optical resonators configured such to realize a wavelet filterbank so that the modulated optical signals ?1,MOD to ?n,MOD undergo WT/IWT in a manner such to obtain optical wavelet transformed signals that can be orthogonally frequency division multiplexed or demultiplexed.

Abstract: This disclosure describes systems, methods, and computer-readable media related to employing rate adaptation in full-duplex communication. A first computing device may establish with a second computing device a full-duplex communication channel having a forward data transmission direction and a reverse data transmission direction. The first computing device may transmit to the second computing device a first data portion in the forward data transmission direction of the full-duplex communication channel at a default data transmission rate. The first computing device may receive a second data portion in the reverse direction of the full-duplex communication channel containing a forward channel quality information (CQI) associated with the forward data transmission direction. The first computing device may transmit a third data portion at a first data transmission rate, wherein the first data transmission rate is based at least in part on the forward CQI contained in the second data portion.

Abstract: The present invention provides a method of transmitting broadcast signals, the method including, encoding service data, building at least one signal frame by mapping the encoded service data, modulating data in the built at least one signal frame by an Orthogonal Frequency Division Multiplexing, OFDM, scheme and transmitting the broadcast signals having the modulated data.

Abstract: Provided herein is a method and apparatus for realizing a frequency-spatial filter with variable bandwidth, the method including generating M number of FFT channel blocks having N number of channels by performing an N point FFT (Fast Fourier Transform) processing using M number of array antenna inputs; combining some of the N number of channels of each FFT channel block according to a frequency bandwidth variable parameter value; combining some of spatial response vector channels in a combined channel of each FFT channel block according to a spatial bandwidth variable parameter value; and combining all the channels and outputting the same.

Abstract: Embodiments of the present disclosure provide a transmitter, a receiver and methods of operating a transmitter and a receiver. In one embodiment, the transmitter is for use with a base station in a cellular communication system and includes a partitioning unit configured to provide first and second groups of guard subcarriers that partition a synchronization portion from data portions in a downlink synchronization signal. The transmitter also includes a transmit unit configured to transmit the downlink synchronization signal. Additionally, the receiver is for use with user equipment in a cellular communication system and includes a receive unit configured to receive a downlink synchronization signal. The receiver also includes a processing unit configured to provide a synchronization portion based on employing first and second groups of guard subcarriers that partition the synchronization portion from data portions of the downlink synchronization signal.

Abstract: In one aspect the embodiments of the invention provide a method that includes transmitting a first frame comprising a first type of message from a first node for reception by a second node. The first node is associated with a first wireless communication system and the second node is associated with a second wireless communication system. The first type of message includes a first information element for identifying the second node and a second information element for specifying that the first frame is transmitted to initiate a request for simultaneous transmission by the first node and by the second node. The first frame is also received by a third node that is part of the first wireless communication system. The method further includes receiving from the third node a second frame that includes a second type of message.

Abstract: Multiple data permutation operations in respective different dimensions are used to provide an overall effective data permutation using smaller blocks of data in each permutation than would be used in directly implementing the overall permutation in a single permutation operation. Data that has been permuted in one permutation operation is block interleaved, and the interleaved data is then permuted in a subsequent permutation operation. A matrix transpose is one example of block interleaving that could be applied between permutation operations.

Abstract: Provided is a radio communication base station device which can suppress a use amount of an SRS communication resource. In this device, a correlation rule setting unit (102) sets a rule for correlating a preamble with an SRS transmission time interval so that the preamble transmission time band and the SRS transmission time band are in the same transmission time band. An SRS transmission band decision unit (103) decides a time interval of a transmission time band which can transmit the SRS according to the preamble transmission time interval inputted from a preamble transmission band decision unit (101) and the correlation rule setting unit (102).

Abstract: Provided are a receiver, a transmitter and a radio communication method capable of using non-orthogonal multiple access while suppressing cost increase and processing delay. A mobile station 200A receives non-orthogonal signals, also receives a reference signal to be used for interference cancellation, and extracts the non-orthogonal signal addressed to the mobile station 200A from the received non-orthogonal signals by demodulating and cancelling the radio signal addressed to another mobile station. In addition, the mobile station 200A demodulates the extracted non-orthogonal signal addressed to the mobile station 200A on the basis of the reference signal. The reference signal is multiplexed in the same radio resource block as a resource block allocated to the non-orthogonal signals, and is multiplexed in the radio resource block only when at least one signal is scheduled in the radio resource block.

Abstract: A method to optimize the communication on a channel between an access point and at least one client device, said channel being characterized by a center frequency and a bandwidth, comprises: establishing a connection on a first channel according to a first center frequency and a first bandwidth; exchanging data through this first channel between the access point and the client device; monitoring a first interference level on the first channel; the access point, while the data are exchanged, executes: informing the client device to switch to a second channel having a different center frequency and/or a different bandwidth; determining a second interference level on the second channel; comparing the first interference level with the second interference level; deciding to switch back or keep the second channel based on the comparison.

Abstract: In a wireless communication base station device, a modulation unit carries out modulation processing for Dch data after coding to generate a Dch data symbol. A modulation unit carries out modulation processing for Lch data after coding to generate an Lch data symbol. An allocation unit allocates the Dch data symbol and Lch data symbol to each sub-carrier composing an OFDM symbol and outputs the allocated sub-carrier to a multiplex unit. In this case, the allocation unit allocates the Dch data symbol to a plurality of resource blocks where one Dch is arranged at an interval equal to integral multiples of the number of resource blocks composing a resource block group.

Abstract: Pilot signal transmission sequences and methods for use in a multi-sector cell. Pilots in different sectors are transmitted at different known power levels. In adjacent sectors a pilot is transmitted while no pilot is transmitted in the adjoining sector. This represents transmission of a NULL pilot signal. A cell NULL is also supported in which NULL pilots are transmitted in each sector of a cell at the same time. Multiple pilot signal measurements are made. At least two channel quality indicator values are generated from measurements corresponding to at least two pilot signals of different power levels. The two values are transmitted back to the base station which uses both values to determine the transmit power requited to achieve a desired SNR at the wireless terminal. The wireless terminal also reports information indicating its location to a sector boundary.

Abstract: The disclosure provides a method and device for allocating a resource location with a frequency hopping function. The method includes: an uplink bandwidth of a Long Term Evolution (LTE) communication system is acquired; it is determined whether frequency hopping information needs to be allocated to uplink continuous frequency-domain resource location information in a multi-antenna port transmission mode, and when the frequency hopping information needs to be allocated, a length of a resource location and frequency hopping bit indicator and a length of frequency-domain resource location information are obtained according to the uplink bandwidth; a difference Value_D between the length of the resource location and frequency hopping bit indicator and the length of the frequency-domain resource location information is calculated; and frequency hopping information is allocated to the frequency-domain resource location information according to the difference Value_D.

Abstract: A first powerline communication device, associated with a first powerline communication network, determines a plurality of time intervals in a beacon period of the first powerline communication network based, at least in part, on variations in levels of interference from a second powerline communication network which shares a powerline communication medium with the first powerline communication network. The first powerline communication device determines at least one channel adaptation parameter for each of the plurality of time intervals in the beacon period to compensate for effects of the variations in the levels of interference from the second powerline communication network. The first powerline communication device applies the at least one channel adaptation parameter corresponding to one or more of the plurality of time intervals in the beacon period when transmitting data via the powerline communication medium.

Abstract: A communication control method is applied to a mobile communication system including a base station that transmits a downlink signal through a plurality of antenna ports, and a user terminal that feeds back precoder matrix information to the base station, the downlink signal being precoded by using a precoder matrix, the precoder matrix information being indicating a precoder matrix preferably used in a downlink. The communication control method comprises: a step of feeding back, by the user terminal, correction value information for correcting the precoder matrix information to the base station when the precoder matrix information is fed back or after the precoder matrix information is fed back.

Abstract: The present invention discloses a method for transmitting a 4-antenna precoding matrix, a user equipment, and a base station. The method includes determining a rank used for indicating the number of transmission layers, determining a first precoding matrix in a codebook set corresponding to the rank, determining a first PMI and a second PMI used for indicating the first precoding matrix, and sending the first PMI and the second PMI used for indicating the first precoding matrix to a base station.

Abstract: An OFDM encoding apparatus for encoding OFDM symbols into an OFDM signal includes: a pre-distortion unit that pre-distorts OFDM symbols into pre-distorted OFDM symbols, the OFDM symbols including payload data and each being carried on multiple OFDM subcarriers; an OFDM generator that generates an OFDM signal from the pre-distorted OFDM symbols by OFDM modulating the pre-distorted OFDM symbols; and a filter that filters the OFDM signal to obtain a filtered OFDM signal, the filter being configured to attenuate the spectrum of the OFDM signal in frequency bands outside the signal bandwidth of the OFDM signal by applying a filter transfer function to the OFDM signal. The pre-distortion unit is configured to apply a pre-distortion transfer function equal to the inverse of the filter transfer function to the OFDM symbols.

Abstract: A method and apparatus for transmitting a signal in a wireless communication system are provided. The method includes: generating R spatial stream each of which is generated on the basis of an information stream and reference signal; generating N transmit streams on the basis of the R spatial streams and a precoding matrix (where R<N); mapping the N transmit streams to at least one resource block; and generating N signals from the N transmit streams mapped to the at least one resource block, and the transmitting the N signals to a user equipment through respective antennas.

Abstract: A method establishing a quality indicator of a radio transmission channel in a first cell of a cellular network using a plurality of orthogonal frequency-division multiplexed subcarriers for transmitting data. A first transmitter located in the first cell transmits a reference control signal including a total-load control signal modulating one or more of the orthogonal subcarriers, during one or more first symbol times dedicated to transmission of symbols other than data symbols, and a useful-load control signal modulating one or more orthogonal subcarriers during at least one second symbol time dedicated to transmission of data symbols. A transmitter located in an adjacent cell transmits an interfering control signal modulating, during the first symbol time(s). The quality indicator is determined according to a measured quality indicator of the channel under the useful load and a measured quality indicator of the channel under the total load.

Abstract: A wireless communication system includes an upper transmission station and a lower transmission station, each serving as a transmission station, a terminal serving as a reception station. The upper transmission station allocates a downlink control channel for each terminal to part of a predetermined data-channel region ascribed to the lower transmission station based on a demodulation reference signal for each transmission station. Based on the allocation result, the lower transmission station allocates the downlink control channel for each terminal, which is disposed at art of the data-channel region thereof. The terminal decodes the downlink control channel based on the demodulation reference signal.

Abstract: A system for processing user input includes an input device, an input processing unit, a high-latency subsystem, a low-latency subsystem, input processing unit software for generating signals in response to user inputs, and an output device. The low-latency subsystem receives the signals and generates low-latency output and the high-latency subsystem processes the signals and generates high-latency output.

Abstract: A flexible OFDM/OFDMA frame structure technology for communication systems is disclosed. The OFDM frame structure technology comprises a configurable-length frame which contains a variable length subframe structure to effectively utilize OFDM bandwidth. Furthermore, the frame structure facilitates spectrum sharing between multiple communication systems.

Abstract: The present invention provides a channel selection method and an apparatus, relates to the field of communications, can improve channel scan and detection efficiency. The method includes: randomly selecting m channels from a preset channel page; determining, from the m channels, a working channel and a spare channel that meet a preset condition; scanning, the working channel of the first superframes and the spare channel of the first superframes in an inactive period of each of the n first superframes according to preset first scan duration, to acquire n energy levels of the working channel and n energy levels of the spare channel; and determining, in an inactive period of the nth first superframe, a working channel for sending a second superframe and a spare channel of the second superframe according to the n energy levels of the working channel and the n energy levels of the spare channel.

Abstract: A method and apparatus are provided for performing acquisition, synchronization and cell selection within an MIMO-OFDM communication system. A coarse synchronization is performed to determine a searching window. A fine synchronization is then performed by measuring correlations between subsets of signal samples, whose first signal sample lies within the searching window, and known values. The correlations are performed in the frequency domain of the received signal. In a multiple-output OFDM system, each antenna of the OFDM transmitter has a unique known value. The known value is transmitted as pairs of consecutive pilot symbols, each pair of pilot symbols being transmitted at the same subset of sub-carrier frequencies within the OFDM frame.

Abstract: The present disclosure discloses a method and an apparatus for resource mapping and code division multiplexing. In the present disclosure, each cell selects a mapping scheme among at least two mapping schemes to implement resource mapping, which effectively reduces interference imposed on reference signal symbols of users at the edge of a cell; vector switching is performed for an orthogonal matrix to obtain multiple different codeword sequences and implement codeword design, so that a problem that the output power of reference signal symbols is unbalanced can be effectively alleviated.

Abstract: The present invention relates to a method for transmitting data units in wireless LAN systems. The method includes the steps of generating a short training field (STF) for a first channel, generating a long training field (LTF) for the first channel, duplicating the STF on at least one second channel, duplicating the LTF on at least one second channel, transmitting the STF and the one or more duplicated STFs through a transmission channel, transmitting the LTF and the one or more duplicated LTFs through the transmission channel, and transmitting a data field through the transmission channel.

Abstract: A method and apparatus of transmitting control information for reduction of inter-cell interference (ICI) in a wireless communication system is provided. The base station transmits one of precoding information and antenna information for every time frequency resource to a second base station based on a ICI reduction method determined by the base station.

Abstract: A method for reducing the crest factor of a wideband signal including N narrowband signals, N being a natural integer greater than or equal to two, the method, implemented by an emitting equipment, including phase shifting the narrowband signals between them in such a way as to reduce the crest factor.

Abstract: The present invention relates to a method in a first User Equipment (UE) served by a radio base station (RBS) of a wireless network, for uplink power control at Multiple User Multiple-Input-Multiple-Output (MU-MIMO) scheduling. The method comprises obtaining a power adaptation parameter for use in uplink transmission power control when the first UE is scheduled to be in pair with a second UE, or is scheduled to be de-paired from the second UE. The method also comprises receiving an indication from the radio base station to use the obtained power adaptation parameter in uplink transmission power control, and adapting an uplink transmission power based on the obtained power adaptation parameter and the received indication. The present invention also relates to the corresponding method in the RBS, and to the UE and the RBS.

Abstract: The invention involves utilizing pieces of disjoint spectral blocks. In one embodiment, a frequency division duplex approach is used, where each spectral block is utilized solely for either uplink or downlink communications. In another embodiment, a time division duplex approach is used, where each spectral block is time divided and uplink and downlink communications are assigned to different time slots within the same spectral blocks. In another embodiment, a code division duplex approach is utilized, where uplink and downlink communications are assigned different codes/hopping patterns within a same spectral block.

Abstract: A mobile communication method is applied to a mobile communication system comprising a general base station that manages a general cell and a specific base station that manages a specific cell having a coverage area smaller than a coverage area of the general cell. The mobile communication method comprises: a step A of notifying, by the general base station, the specific base station of scheduling information indicating an uplink radio resource to be assigned to general mobile terminals that are mobile terminals in a connected state in the general cell, at a time interval of a predetermined time; and a step B of notifying, by the specific base station, the general base station of general mobile terminal interference information indicating interference that the specific cell receives according to the uplink signals transmitted from the general mobile terminals at the time interval of the determined time.

Abstract: Methods, apparatuses, and computer program products for signal detection and classification are provided. One method includes detecting, by a station, a presence of a signal and classifying the signal according to type. There may be at least three possibilities for the type of signal. The classifying may include performing a composite hypothesis test, such as a generalized likelihood ratio test (GLRT) for the at least three possibilities.

Abstract: The present invention relates to methods and apparatus in a RBS and a UE for reference signal (RS) measurements in an OFDM system, that enable having a configurable RS transmission bandwidth which is smaller than the system bandwidth. This allows for better interference coordination of RS, which in turn improves the UE RS measurements used for different services such as positioning. The RBS retrieves the RS transmission bandwidth, determines a RS measurement bandwidth based on this RS transmission bandwidth, and transmits the determined bandwidth to the UE. The UE receives the RS measurement bandwidth and measures the RS in a bandwidth determined based on the received measurement bandwidth and the UE capability.

Abstract: The set of resource aggregation levels available for forming an enhanced control channel message may vary from one subframe to another, based on the level of puncturing in the transmitted subframes. An example method begins with determining members of a set of aggregation levels usable to aggregate the non-overlapping subsets of resource elements for transmitting downlink control information. This determining is based on a puncturing level to be used for the transmission of the downlink control information. Downlink control information for the given subframe is mapped to one or more non-overlapping subsets of resource elements in the at least one block of time-frequency resources, according to an aggregation level selected from the determined set, and then transmitted, in the one or more non-overlapping subsets. This method may be repeated for each of several subframes, where the puncturing may differ from one subframe to another.

Abstract: Methods, an apparatus, and a network manager for cooperative communication are provided. A method of communication by a serving base station performing a cooperative communication with a plurality of base stations includes selecting serving channel code information based on Channel Status Information (CSI) of the serving base station, receiving cooperating channel code information based on CSI of a cooperating base station from the cooperating base station performing the cooperative communication with the serving base station, determining a compensation parameter based on the serving channel code information and the cooperating channel code information, and determining a beamforming vector of the serving base station based on the compensation parameter.

Abstract: Pilot logic may determine based upon channel and phase information how to process pilot tones that shift locations every N symbols in an orthogonal frequency division multiplexing (OFDM) packet transmission. Pilot logic may determine a signal-to-noise ratio (SNR) for the channel to determine how to process the shifting pilot tones. Pilot logic may also determine channel and phase information updates such as channel state information and phase correction information from pilot tones. In situations of high SNR, logic may use channel estimates and phase rotations that are obtained from locations of the pilot tones for phase tracking and updating the equalizer. In situations of low SNR, logic may use the phase rotations for phase tracking and not update the equalizer during the OFDM transmission. Logic may also determine the presence or absence of a Doppler effect on the transmission and transmit a selection for N to an access point in response.

Abstract: MIMO UWB Communications apparatus is configured to send out a channel estimation sequence comprising a plurality of sequentially transmitted symbols in accordance with a first band hopping sequence, sent from one antenna of the apparatus, while another antenna is transmitting another sequence of channel estimation symbols in accordance with another, complementary band hopping sequence. A legacy device will be capable of synchronizing with the channel estimation symbols sent in accordance with the first band hopping sequence, while a MIMO receiver will be able to determine channel estimates for all MIMO channels on the basis of the combined channel estimation transmissions.

Abstract: An apparatus is configured to perform a method for providing a wireless communication service to at least one User Equipment (UE) from among a plurality of UEs having links established with a distributed small Base Station (BS) in a Virtual Cell Network (VCN) system in which a plurality of virtual cells exist within one macro cell. The method includes selecting at least one UE to which a wireless communication service is to be provided in a virtual cell, calculating a feedback allocation amount for each of the selected at least one UE, by sharing path losses and user characteristics measured and determined on a UE basis by each of the plurality of virtual cells, and providing information about the calculated feedback allocation amount to the selected at least one UE.

Abstract: A transmitter generates and transmits a low rate signal to its intended receiver. Upon receiving the low rate signal, the intended receiver generates and transmits a channel sounding response (CSR), said CSR being a short burst having a predefined transmit format and carrying predetermined information. The transmitter then analyzes the CSR and determines uplink channel response, estimates downlink channel response, and determines appropriate transmit parameter settings based on the analysis and downlink response estimate. Adjustment of the transmit parameters can be made in either the MAC or PHY layer or in a combination of both. After adjusting its transmit parameters and modulating sub-carriers with user-data according to the determined transmit settings, the transmitter transmits the user-data to the receiver on a preferred portion of bandwidth.

Abstract: A multi-bit HARQ feedback is transmitted by a receiver to a transmitter. The multi-bit feedback is a function of a level of convergence reached by a decoder when the previously transmitted coded data bits were decoded. The transmitter is configured to select a set of coded data bits for a retransmission as a function of the multi-bit feedback. In some embodiments, different redundancy versions of the coded data bits may be selected as a function of the multi-bit feedback. In other embodiments, a bit puncturing or bit repetition pattern may be selected as a function of the multi-bit feedback.

Abstract: Fiber, cable, and wireless data channels are typically impaired by reflectors and other imperfections, producing a channel state with echoes and frequency shifts in data waveforms. Here, methods of using OTFS pilot symbol waveform bursts to automatically produce a detailed 2D model of the channel state are presented. This 2D channel state can then be used to optimize data transmission. For wireless data channels, an even more detailed 2D model of channel state can be produced by using polarization and multiple antennas in the process. Once 2D channel states are known, the system turns imperfect data channels from a liability to an advantage by using channel imperfections to boost data transmission rates. The methods can be used to improve legacy data transmission modes in multiple types of media, and are particularly useful for producing new types of robust and high capacity wireless communications using non-legacy OTFS data transmission methods.

Abstract: A method and apparatus of transmitting a PPDU in a wireless communication system is provided. The method includes selecting a subchannel among a plurality of subchannels, wherein a PLCP preamble and a PLCP header in each PPDU are independently generated in each of the plurality of subchannels, and transmitting a PPDU in the selected subchannel.

Abstract: According to one embodiment, a network device is configured to measure a quality of service associated with a real-time streaming packet received at a first transmission rate. The network device gathers metrics to a call quality based on the quality of service, wherein the metrics are specific to a wireless call quality, and adjusts the first transmission rate to a second transmission rate based on the metrics. Herein, the second transmission rate replaces the first transmission rate to balance between a transmission delay and reliability of the real-time streaming packet.

Abstract: A mobile station includes: a physical channel segmentation unit to receive radio signals including multiple orthogonal signals which are orthogonal to each other, and multiple non-orthogonal signals which are not orthogonal to each other; and data demodulating/decoding units to extract the non-orthogonal signal addressed to the mobile station from the multiple non-orthogonal signals by demodulating and cancelling the radio signal addressed to another mobile station by use of the orthogonal signals included in the radio signals received by the physical channel segmentation unit, and demodulate the signal included in the orthogonal signals and addressed to the mobile station, and the extracted non-orthogonal signal addressed to the mobile station.

Abstract: Multichannel signal generator performance characterization employs orthogonal modulation to characterize a relative performance of channels of a multichannel signal generator. The performance characterization includes generating a first signal in a first channel of the multichannel signal generator and generating a second signal in a second channel of the multichannel signal generator. The first and second signals include an orthogonal frequency-division multiplexing (OFDM) digital modulation having a first set of subcarriers assigned to the first signal and a second set of subcarriers assigned to the second signal. Performance characterization further includes combining the first signal and the second signal to produce a combined signal along with receiving and demodulating the combined signal according to the OFDM digital modulation using a digital receiver and determining a performance parameter of the second channel relative to the first channel from the received and demodulated combined signal.