Abstract: Methods, apparatuses, and computer program products are disclosed that facilitate an early decoding of relay signals. A relay receives a signal within a sub-frame from a network. A first and second reference symbol is detected within the sub-frame such that the first reference symbol is detected before the second reference symbol. The signal is then decode based on the first reference symbol.

Abstract: A communications system may include a first wireless communications device communicating based upon a first wireless communications protocol, a second wireless communications device communicating based upon a second wireless communications protocol different from the first wireless communications protocol, and a wireless base station. The wireless base station may communicate with the first wireless communications device and the second wireless communications device based upon a frame structure. The frame structure may be defined by sub-carriers at respective different frequencies and symbols at respective different times. The frame structure may include a frame control header, a first frame portion for communicating with the first wireless communications device based upon the first wireless communications protocol, and a second frame portion for communicating with the second wireless communications device based upon the second wireless communications protocol.

Abstract: A radio communication apparatus for transmitting and receiving modulation signals of a plurality of channels in the same frequency band via a plurality of antennas. A communication method is based on information on electric wave propagation environment corresponding to each antenna of the communication partner and transmission is performed by selecting a transmission method for transmitting modulation signals of channels in the same frequency band from a plurality of antennas or a transmission method for transmitting a modulation signal of one channel from one antenna. Thus, it is possible to multiplex a plurality of modulation signals so as to be transmitted and to demultiplex and demodulate the transmitted multiplexed modulation signals at a reception unit, thereby improving the data transmission rate.

Abstract: An OFDM (orthogonal frequency division multiplexing) receiver is equalized by dividing each of a plurality of received OFDM symbols into a plurality of sub-symbols and outputting each of Fourier-converted signals corresponding to each of the sub-symbols, and estimating a channel response corresponding to each of the divided sub-symbols.

Abstract: A method and an apparatus for receiving a Minimum Mean-Squared-Error (MMSE) in a Single-Carrier Frequency Division Multiple Access (SC-FDMA) system is provided. The method includes, transforming a signal in a time domain received through an antenna into a signal in a frequency domain, and discriminating between bands respectively allocated to terminals in a frequency domain, estimating a channel and computing a weight value from the signal transformed into the frequency domain, and detecting an MMSE, computing a time-domain bias from the weight value and a channel estimation value of the signal transformed into the frequency domain, normalizing the detected MMSE by using the computed time-domain bias, and transforming the normalized signal into a normalized signal in a time domain, decoding the normalized signal transformed to the time domain, and transmitting the decoded normalized signal transformed into the time domain to each of the terminals.

Abstract: An apparatus and method of scheduling timing packets to enhance time distribution includes an improved apparatus in a system in which at least one of time and frequency information is derived based on information distributed in timing packets, at least some of the timing packets being transmitted by or received by the apparatus. The improvement includes a scheduling module that determines a first packet transmission time offset of a first timing packet based on a first predetermined identifier associated with the apparatus, and a second packet transmission time offset of a second timing packet based on the first packet transmission time offset and a timing packet spacing that is independent of the first predetermined identifier. The improvement further includes a transmission module that transmits the first timing packet based on the first packet transmission time offset, and the second timing packet based on the second packet transmission time offset.

Abstract: A transmitting device for transmitting data and pilot symbols in an OFDM transmission system having transmission antennas. The device includes symbol generating means for generating data and pilot symbols, means for transmitting the data and pilot symbols using subcarriers of the OFDM system. The symbol generating means generates a first and second type pilot symbol, the second having an inverted value of the first so that a first pilot symbol pattern to be transmitted by using one of said plurality of transmission antennas has a different pattern in the frequency and time dimension from a second pilot symbol pattern to be transmitted by using another transmission antenna. First and second pilot symbols are comprised in respective first and second pilot symbol patterns, where at least some of the first and second pilot symbols have the same time allocation and being alternately identical and inverted to each other.

Abstract: An apparatus and associated methods to implement a high throughput wireless communication system are generally presented.

Abstract: A method and a system for selecting antennas in an orthogonal frequency division multiple access (OFDMA) network. The network includes a base station and mobile stations. The mobile station includes multiple antennas. The base station and the mobile stations communicate with each other using frames. The base station transmits a down-link (DL) subframe of the frame to the mobile station. The DL subframe allocates one or more symbols and one or more subcarriers of an up-link (UL) subframe of the frame for antenna selection signals. The mobile station transmits the UL subframe including the antenna selection signals at the allocated subcarriers and symbols to the base station. Then, the base station selects a subset of the antennas based on the antenna selection signals.

Abstract: Broadcast or multicast traffic is classified into different types of traffic and different transmission schedules associated with each of the different types of traffic. The different types of broadcast and multicast traffic may be implemented in an 802.11-based system where an access point is configured to classify broadcast and multicast traffic into different types and assign different transmission schedules to each of the different traffic types. An associated wireless station may thereby wake from a power save mode only at intervals corresponding to delivery times of the types of traffic that the wireless station has elected to receive. In some aspects the different types of broadcast and multicast traffic may comprise user plane traffic and control plane traffic.

Abstract: A coaxial network communication node receives multimedia content with one or more other nodes in a coaxial network. The node determines a delay-spread of a coaxial channel based on receipt of a probe from a transmitting node and configures a channel-shortening time-domain equalizer (TEQ) filter to effectively shorten the channel based on the delay spread. The node instructs the transmitting node to shorten a length of a cyclic prefix for subsequent packet-based transmissions to be received from the transmitting node. The probe is stored and reused until the channel-shortening TEQ filter converges. The nodes may be configured to communicate in accordance with the Multimedia over Coax Alliance (MoCA®) specifications.

Abstract: A technique for generating a Single-Carrier Frequency Division Multiple Access, or SC-FDMA, signal having a transmission bandwidth and comprising a Constant Amplitude Zero-Autocorrelation, or CAZAC, sequence of length NCAZAC is described. It will be assumed that the SC-FDMA signal has a time domain formulation with a term representative of an Inverse Discrete Fourier Transform, or IDFT, of length M, with M>NCAZAC.

Abstract: A wireless communication device for receiving a frame corresponding to a transmission time interval, the frame having a control channel including at least two control channel elements and an embedded bit sequence, the location of which indicates a portion of the control channel used for radio resource assignment, wherein the portion of the control channel used for radio resource assignment may be less than the entire control channel of the frame having the embedded bit sequence, and wherein the at least two frames may use different portions of the control channel for radio resource assignment.

Abstract: A method, apparatuses, and system of broadcasting content data in a macro-diversity region of a data frame includes receiving a stream of transport packets. Selecting at least one burst size, from amongst a set of a plurality of predetermined burst sizes. Allocating one or more data bursts with the selected burst size to the macro-diversity region of the data frame, each data burst comprising at least a portion of the received transport packets and wherein the at least one burst size is selected so as to minimize a number of data bursts allocated to the macro-diversity region. Then communicating the allocation of data bursts to a transmitter that includes the allocation of data bursts in the macro-diversity region of a data frame transmitted by the transmitter.

Abstract: A method and apparatus for transceiving additional data using unallocated slots of a header of a frame used in a broadcast system are provided. A data transceiving apparatus includes a data transmitter for encoding, modulating, and transmitting a broadcast frame including a first region containing broadcast data and a second region containing additional data and a data receiver for receiving the broadcast frame, extracting at least any of the broadcast data and the additional data from the broadcast frame, and processing the broadcast data and the additional data independently.

Abstract: The invention involves management of communication resources (40, 45) in a network (1) utilizing multi-node-adapted resources (40) for transmission of multi-node-associated information and single-node-adapted resources (45) for transmission of single-node-associated information. A default resource allocation (60) specifying, for all transmitter nodes (10, 15) in the network (1), when the respective resource type is available for usage is defined. A subset (10) of the nodes in the network (1) estimates an expected amount of multi and/or single-node-associated information to be transmitted by the node subset (10). The default resource allocation (60) is then dynamically adjusted, for the node subset (10), based on the estimated expected information amount, implying that the physical resources (40, 45) defined by the default time structure (60) are dynamically shared in the frequency domain.

Abstract: The present invention relates to a transmitting device and a receiving device in a wireless orthogonal frequency division multiplex (OFDM) communication system with space time transmit diversity (STTD). Further, the present invention relates to a channel estimation method for performing a channel estimation in such a wireless communication system, in which the transmitting device comprises a first and a second antenna for transmitting signals with space time transmit diversity. The first and the second antenna means are arranged spaced apart from each other in a space diversity arrangement, whereby first and second pilot symbols are transmitted via said first and said second antenna means, respectively.

Abstract: A method reduces channel interference in a communication system that includes base stations and terminal stations with each base station having a plurality of sectors, each sector having a channel, and with each terminal station associated with a sector of a base station. A first set of terminal stations associated with a first sector that may potentially interfere with a second set of terminal stations associated with a second sector is determined. A first frequency sub-channel for use by the first set of terminal stations is selected and a second frequency sub-channel for use by the second set of terminal stations is selected. Transmissions by the first set of terminal stations are coordinated with transmissions by the second set of terminal stations, thereby reducing channel interference between the terminal stations of the first set and the terminal stations of the second set, as seen by a base station in the first or second sector.

Abstract: An apparatus and method for controlling amount of information to be fed back in a multiple antenna system in a multi-user environment. The apparatus includes a channel estimator which estimates channel values by using an input signal; a Singular Value Decomposition (SVD) operator which decomposes singular values from the estimated channel values; and a feedback determining unit which uses the singular values to compute channel capacity that can be obtained according to the amount of channel information to be fed back, and selects the channel information to be fed back by using the channel capacity.

Abstract: System and method for adaptively allocating channels to subchannels and maintain balance on the subchannels. A preferred embodiment comprises an assignment unit (for example, assignment algorithm unit 717) that receives call/connection requests from a call/connection processing unit (for example, call/connection processing unit 712). The assignment unit may use a lookup table or channel metrics to determine an allocation for the call/connection to maintain a balance across the subchannels. The assignment unit may allocate only the call/connection in the request or it may allocate the call/connection in the request plus the calls/connections that are already allocated to achieve balance.

Abstract: Dynamic time-spectrum block allocation for cognitive radio networks is described. In one implementation, without need for a central controller, peer wireless nodes collaboratively sense local utilization of a communication spectrum and collaboratively share white spaces for communication links between the nodes. Sharing local views of the spectrum utilization with each other allows the nodes to dynamically allocate non-overlapping time-frequency blocks to the communication links between the nodes for efficiently utilizing the white spaces. The blocks are sized to optimally pack the available white spaces.

Abstract: A multi-channel superheterodyne receiver employs a low intermediate frequency (IF) and both high-side injection and low-side injection of a selected local oscillator (LO) signal into the mixer in order to position image frequencies outside the passband of a single image reject filter. Any channel that falls within a used portion of the image reject filter passband can be downconverted with image rejection if the utilized bandwidth portion is no greater than about 4 times the IF minus the bandwidth of a channel in the filter passband. Low side injection is used for channels falling within the lower half of the passband of the image reject filter, while high-side injection is used for channels falling within the upper half thereof. The image always remains outside the passband and the receiver can accommodate a greatly increased number of channels.

Abstract: Methods and apparatus operative in a wireless communications system divide a communications resource available for performing information transmission and retransmission operations into a plurality of communication resource units. The units are ordered in a predetermined order. A first group of communication resource units are selected from the communication resource in ascending order and assigned to a first group of communications devices to perform information transmission operations in a first time period. A second group of communication resource units are selected from the communication resource in descending order and assigned to a second group of communications devices to perform information transmission operations in a second time period. At least a portion of the first group of communication resource units is assigned to the first group of communication resource units to perform retransmission operations.

Abstract: The present invention discloses a method for inserting a downlink common pilot in a TDD system and more particularly to a method for inserting a downlink common pilot in a TDD system based on OFDMA technology and the method includes two steps. A: data to be transmitted are divided into several segments to be transmitted in several continuous time periods, wherein each time period includes several slots with at least one downlink slot; B: a common pilot is inserted in one downlink slot in the time period. Therefore, the scheduling based on the frequency domain can be achieved by measuring the common pilot channel.

Abstract: A serial intelligent cell (SIC) and a connection topology for local area networks using Electrically-conducting media. A local area network can be configured from a plurality of SIC's interconnected so that all communications between two adjacent SIC's is both point-to-point and bidirectional. Each SIC can be connected to one or more other SIC's to allow redundant communication paths. Communications in different areas of a SIC network are independent of one another, so that, unlike current bus topology and star topology, there is no fundamental limit on the size or extent of a SIC network. Each SIC can optionally be connected to one or more data terminals, computers, telephones, sensors, actuators, etc., to facilitate interconnectivity among such devices. Networks according to the present invention can be configured for a variety of applications, including a local telephone system, remote computer bus extender, multiplexers, PABX/PBX functionality, security systems, and local broadcasting services.

Abstract: A set of piconets and corresponding methods and computer programs may reduce contention time between piconets. In one embodiment, a seven-length code architecture may be used with group(s) of bands so that contention time cannot exceed 1/7 of the time. Up to seven different bands can be used within each group. When less than seven bands are used (e.g., three or six), at least one of the bands may be assigned to more than one dwell time during a time span. Alternatively, each dwell time within the time span may be assigned to a different band. The state may be changed as needed or desired. Substitution of extra bands may also be used. Using either scheme (repeated bands or changing states), a prime-number architecture can be used with a non-prime number of different bands. Simultaneous communications using at least two bands within a piconet may be used.

Abstract: A channel estimator for use in a receiver node receiving signals from a plurality of user terminals wherein each user terminal is allotted a respective set of transmission subcarriers and respective test signal sequences for transmission over the channel to be estimated. The channel estimator has stored therein information as to the respective sets of transmission subcarriers allotted to the user terminals for transmission as well as the discrete spectra of the respective test signal sequences allotted to the user terminals. Upon receiving from a plurality of user terminals signals including the respective test signal sequences transmitted over the channel by using the respective sets of transmission subcarriers allotted thereto, the estimator generates the discrete spectrum of the combined test signal received and performs channel estimation as a function of the discrete spectrum of the combined test signal and the discrete spectra of the test signal sequences allotted to the user terminals.

Abstract: The present invention provides a method for detecting a reverse rate indicator channel. The method may include accessing first encoded information indicative of a data rate and a first sub-packet identifier associated with a sub-packet, accessing second encoded information indicative of the data rate and a second sub-packet identifier associated with the sub-packet, and modifying the second encoded information. The method may also include combining the first encoded information and the modified second encoded information, and decoding the combined first and modified second encoded information.

Abstract: System and method for providing multiple access in a multi-band, orthogonal frequency division multiplexed (multi-band-OFDM) communications system. A preferred embodiment comprises determining a transmission bandwidth to support a performance requirement and configuring transmission bands in the multi-band-OFDM communications system based upon the transmission bandwidth, wherein the transmission bands may be made up of smaller transmission bands bonded together. Further comprising initializing communications with the configured transmission bands. The use of bonded transmission bands can provide increased data rates and/or increased range performance.

Abstract: The present invention concerns a method for estimating the time-dispersion of a channel comprising D subchannels, wherein one computes from a received signal a set of estimated Channel Transfer Factors (CTF's) ?[?], where ?(0???D) is the subchannel number, said method comprising a step of calculating, for a predetermined strictly positive integer d, a correlation factor Cd representing the correlations, both in amplitude and in phase, between pairs ?[?] and ?[?+d] of said computed CTF estimates. By an appropriate choice of d, the time-dispersion resolution can be adapted to most prevalent channels. The correlation is optionally corrected according to the mean channel estimation signal-to-noise ratio. This method can be used for many applications where knowing the time-dispersion characteristics of a channel is required, and is, for example, particularly suitable for designing a channel estimation filter, and for link adaptation. Application to devices and apparatus implementing these methods.

Abstract: A system (100) and method (400) for peak limiting suitable for use in a communication system is provided. The method can include modulating (402) a symbol vector to produce a modulated waveform (500), wherein the symbol vector contains at least one symbol in at least one subcarrier (130), computing (404) at least one symbol adjustment that is based on at least one peak overshoot (512) of the modulated waveform, and applying (406) the at least one symbol adjustment to the symbol vector in accordance with an assigned weighting for reducing a peak power of the modulated waveform. The method limits an energy in the at least one subcarrier to a prespecified level of distortion.

Abstract: A method of configuring a sub-slot having a layer-modulated multi-user packet (MUP) is disclosed. More specifically, the method comprises modulating symbols associated with a first layer by using non-layered modulation scheme, and modulating symbols associated with a second layer and a third layer using a different layered-modulation scheme. Here, the symbols associated with the second layer and the third layer are multiplexed by any one of an orthogonal frequency division multiplexing, a code division multiplexing, a multi-carrier code division multiplexing, or a time division multiplexing.

Abstract: A method for multiplexing a control information stream, and a data information stream comprised of systematic symbols and non-systematic symbols in a wireless mobile communication system is described. The multiplexing method includes mapping the data information stream to a resource area, so that the systematic bit symbols are not mapped to a specific resource area where the control information stream is to be mapped, and mapping the control information stream to the specific resource area.

Abstract: A digital broadcasting system and a method of processing data are disclosed, which are robust to error when mobile service data are transmitted. To this end, additional encoding is performed for the mobile service data, whereby it is possible to strongly cope with fast channel change while giving robustness to the mobile service data.

Abstract: An apparatus and a method for supporting multiple links in a multi-hop relay cellular network using at least two frequency bands are provided. A subframe for a link on which a Mobile Station (MS) or a Relay Station (RS) communicates with a Base Station (BS) is configured in a first frequency band, and a subframe for a link on which the BS or the RS communicates with the MS is configured in a second frequency band.

Abstract: A multiple-input multiple-output (MIMO) wireless communication system. A transmitter that includes a plurality of transmit antennas selects one of a spatial multiplexing scheme and a spatial diversity scheme, processes a signal in the selected transmission scheme, and transmits the signal through the plurality of transmit antennas. A receiver that includes a plurality of receive antennas processes a signal in a reception scheme mapped to a transmission scheme of the transmitter. The transmission schemes include a transmission scheme for maximizing diversity gain and a transmission scheme for maximizing spectral efficiency. The MIMO communication system using an adaptive transmission mode switching technique performs switching between MIMO transmission modes using spatial selectivity of a channel, thereby obtaining maximum gain in a signal to noise ratio (SNR) and spectral efficiency according to channel state.

Abstract: Resources of two frequency division duplex (FDD) frequency bands at a distance from each other are allocated for transmissions by a time division duplex (TDD) transmission method. The resources in the first FDD frequency band are allocated for FDD transmissions in the uplink and for TDD transmissions predominantly in the uplink as the primary transmission direction, and in a secondary manner in the downlink as the secondary transmission direction. The resources in the second FDD frequency band are allocated for FDD transmissions in the downlink and for TDD transmissions predominantly in the downlink as the primary transmission direction and in a secondary manner in the uplink as the secondary transmission direction. No resources are allocated for time periods of an allocation of resources for one of the secondary transmission directions in the first and second frequency bands, for FDD transmissions in the counter transmission direction to this secondary transmission direction.

Abstract: The present invention relates to a method and apparatus for scheduling data for transmission via at least two half-duplex time division multiple access connections, wherein for each connection respective capacities of data portions to a transmission frame are allocated so that the total capacity of all data portions of the transmission frame does not exceed a predetermined capacity for each transmission direction, and that the sum of capacities of data portions of each connection of the transmission frame in both transmission directions does not exceed the predetermined capacity. Then, the transmission timing of the data portions within the transmission frame is set in such a manner that transmission and reception intervals of each connection do not overlap. Accordingly, scheduling can be optimized to meet both QoS and half-duplex requirements.

Abstract: A circuit structure for a transmission network node for transmitting high bit-rate, IP-based time division-multiplexed signals, especially for an optical Multi-Gigabit Ethernet. The structure includes a bidirectional remote ports at two sides, each receiving and transmitting time-division multiplexed signals. Each time division-multiplexed signal has a frame structure with a number of virtual time slots each transporting certain contents. The path-switch unit is constructed to execute switching functions for realizing a drop function, a pass-through function, and a drop-and-continue function. Channel cards and network structures are also provided.

Abstract: A base station apparatus in a CDMA/TDD mobile communication system is provided. A signal is formed employing a frame configuration with a plurality of time slots and spreading processing utilizes a long spreading code for identifying a cell and a short spreading code for acquiring frame synchronization. The base station apparatus includes a first control channel former that forms a first control channel including a symbol that is spread by a first short spreading code. A second control channel former forms a second control channel including a symbol spread by a second short spreading code and positioned at a same timing as the symbol spread by the first short spreading code.

Abstract: A transmitting device for transmitting data symbols and pilot symbols in an OFDM transmission system; the device comprising symbol generating means for generating said data symbols and said pilot symbols, means for transmitting said data symbols and pilot symbols respectively by using a plurality of subcarriers of said OFDM transmission system, wherein said symbol generating means is designed to selectively generate a first type pilot symbol and a second type pilot symbol being orthogonal to said first type pilot symbol so that a pilot symbol pattern in the frequency dimension comprises at least said first type pilot symbol to be transmitted by using a predefined subcarrier and second type pilot symbol to be transmitted by using other predefined subcarrier, and wherein said pilot symbol pattern has a different pattern from a succeeding pilot symbol pattern in time dimension.

Abstract: A method for transmitting/processing data in a wireless communication system, and a transmitter are disclosed. A method processing method for data transmission at a transmitting side of a wireless communication system employing multiple carriers comprises performing a symbol mapping process on a binary data sequence, and generating a symbol sequence, converting the symbol sequence into a time-domain symbol using a plurality of sub-carriers having a variable sub-carrier spacing therebetween, and adding a cyclic prefix to the time-domain symbol.

Abstract: A method of scheduling and sub-channelization is provided for a wireless network such as an OFDMA network. Distributed coordination is applied across sectors, such neighboring sectors will tend to schedule cell-edge users at the same time, while sub-channelizing to different portions of the full frequency band available for forward link transmissions. This tendency is achieved by dividing each sector's users into user classes which depend upon forward link channel quality. Each user class is assigned a different set of priorities for use of available timeslots and subcarriers.

Abstract: A method and apparatus are described that facilitate reducing intra-cell interference and meanwhile randomizing inter-cell interference without cell planning. Segment time-frequency patterns can be obtained to form multiple different segment time-frequency pattern sets where the segment time-frequency patterns in one time-frequency pattern set are orthogonal to each other. Randomly select at least one segment time-frequency pattern set in each TTI. Within each TTI, at least one user and/or traffic channel in one cell may be randomly assigned to at least one segment time-frequency pattern of the segment time-frequency pattern set.

Abstract: For quasi-orthogonal multiplexing in an OFDMA system, multiple (M) sets of traffic channels are defined for each base station. The traffic channels in each set are orthogonal to one another and may be pseudo-random with respect to the traffic channels in each of the other sets. The minimum number of sets of traffic channels (L) is used to support a given number of (U) terminals selected for data transmission, where M?L?1 and U?1. Each terminal transmits data and pilot symbols on its traffic channel. A base station receives data transmissions from all terminals and may perform receiver spatial processing on received symbols with spatial filter matrices to obtain detected data symbols. The spatial filter matrix for each subband may be derived based on channel response estimates for all terminals transmitting on that subband.

Abstract: According to the present invention, when a terrestrial digital broadcasting is carried out by applying an OFDM modulation to transport streams MPEG-2 Systems, the plural transport streams subject to a connected transmission are divided into groups and these transport streams are coordinated. Then, a broadcasting station generates a connected transmission descriptor for coordinating the plural transport streams steams subject to the connected transmission and describes the generated connected transmission descriptor in an NIT to multiplex the transport streams.

Abstract: A method, system, and computer program product for frame and frequency synchronization in packet-based Orthogonal Frequency Division Multiplexing (OFDM) in wireless digital communication systems. An OFDM packet includes a preamble preceded by a Cyclic Prefix (CP). The method includes computing a timing metric for packet-based OFDM. The timing metric yields a sharp peak at a preamble boundary. The preamble boundary is detected, based on a threshold. The threshold is determined a priori, based on mean and variance of the timing metric at the preamble boundary and in its neighborhood. The mean and the variance are evaluated for an Additive White Gaussian Noise (AWGN) channel. The detection of the preamble boundary enables frame synchronization in packet-based OFDM. The method further involves the task of frequency-offset estimation, using the preamble. The frequency-offset estimation enables frequency synchronization in packet-based OFDM.

Abstract: A method for transmitting a signal of a medium access control sublayer in a mobile communication system which has mobile and base stations for providing a bearer service. A bearer service profile type is decided according to a bearer service combination type of the bearer service for the provision of the bearer service. A transport format indicator is set according to the decided bearer service profile type, and a transport format combination indicator is appended to a dedicated physical control channel. The most efficient data is transmitted on the basis of a service type and a measured radio environment result. Therefore, a data frame format most suitable to a channel environment can be produced, thereby providing the best service.

Abstract: A multi-tone modem with components forming a transmit path and a receive path configured to couple to a wired communication medium for at least intermittent communication of frequency division multiplexed multi-tone modulated communication channels thereon. A Fourier transform component transforms received communication channels between a time domain and a frequency domain and vice-versa. Selected components on the receive path determine alignments between the received multiplexed communication channels in the time domain using alignment determinations made in both a time domain and frequency domain portions of the receive path. The Fourier transform component transforms a stream of digitized samples of the received multiplexed communication channels from the time to the frequency domain using the alignment determinations made by the selected components on the receive path.

Abstract: In one embodiment, the invention comprises a channel estimation method, comprising determining a FFT window position, and calculating a delay spread. In another embodiment, the step of determining a FFT window position comprises setting an initial position of the FFT window, computing an energy for each tap, time averaging said energy for each tap, comparing an average energy of each tap with a first threshold multiplied by the average energy of all taps, comparing the average energy of each tap with a second threshold multiplied by a maximum average energy in alias components, updating the set of paths if the average energy of the tap is greater than said second threshold multiplied by the maximum average energy in alias components; and refining the FFT window position.