Abstract: In at least some embodiments, a communication system includes a receiver having a local oscillator (LO) for each of a plurality of frequency bands. Each LO is controlled by a separate phase-locked loop (PLL) that tracks carrier frequency offset (CFO) using a common phase error (CPE). The CPE is selectively weighted based on at least one inter-band frequency correlation (IFC) coefficient.

Abstract: A novel and useful mechanism for the detection, estimation and correction of far-end cross talk (FEXT) caused by transmissions over adjacent wire pairs or cables. The detection, estimation and correction technique of the invention can be used to identify and compensate for FEXT impairments in Ethernet and DSL systems. The detection, estimation and correction is performed utilizing one of several techniques including linear forward filtering, backward decision feedback based filtering and a combination thereof. Results of simulations are presented illustrating the performance improvements provided by the present invention.

Abstract: In at least some embodiments, a method is provided. The method includes receiving samples from a first input channel and a second input channel. The method further includes controlling commutators to selectively switch samples between the first and second input channels for input to a radix-2 butterfly. The method further includes continuously activating the radix-2 butterfly while processing samples received from the first input channel followed by samples received from the second input channel.

Abstract: In at least some embodiments, a system may comprise one or more devices configurable to communicate according to a first protocol that implements a first data packet, and one or more devices configurable to communicate according to a second protocol that implements a second data packet having a predetermined quadrature component. The one or more devices configurable to communicate according to the second protocol associate detection of the predetermined quadrature component with a function that is not supported by the one or more devices that communicate according to the first protocol.

Abstract: A multi-carrier (MC) receiver receives a multi-carrier signal containing data symbols as well as pilot symbols. The MC receiver estimates a carrier frequency offset in a downconverted base-band multi-carrier signal in the frequency domain based on deviations of one or more characteristics of the pilot signals from predetermined values, and corrects for the offset in the time domain. In an embodiment, a second order phase locked loop (PLL) estimates the phase of the pilot signals to determine the carrier frequency offset. Changes in pilot phases caused due to the time domain correction are cancelled to allow the PLL to minimize deviations from the lock position.

Abstract: A method to determine bit error rate (BER) for a given channel of a communication system includes determining a first statistical representation of at least one deterministic source of noise for the given channel. A parametric statistical representation having parameters that model non-deterministic noise is defined for the given channel and values for the parameters of the parametric statistical representation are estimated to provide a second statistical representation for the non-deterministic noise based on at least one of measurements and simulations performed for the given channel. The BER of the given channel is estimated as a function of the first and second statistical representations.

Abstract: A wireless device receives an input signal representing a signal of interest (e.g., one or more portions of a packet) on a wireless medium. The input signal may, in addition, contain narrowband interference signals. The wireless device removes the signal of interest from the input signal to produce a residue signal, and analyzes the residue signal to determine the presence of any interference bands in which narrowband interference signals may be present. The wireless device then removes the detected interference bands from the input signal. The residue signal may reveal the presence of interference signals, which might otherwise be hard to distinguish in the input signal. Thus, interference signals with power levels much lower than the power of the signal of interest may be detected and removed.

Abstract: Methods and apparatus to perform dynamic channel management and dynamic bandwidth changes in wireless local area networks are disclosed. A disclosed example method comprises deciding at an access point to initiate at least one of a bandwidth change or a channel assignment change; and sending a frame to initiate the at least one of the bandwidth change or the channel assignment change from the access point to one or more stations of a wireless network, the frame including a first field to identify a first channel and a second field to identify a second channel.

Abstract: Timing recovery circuitry for a digital subscriber line (DSL) modem, including a combined frame and timing function for adjusting frame alignment, and for adjusting sample frequency for frequency offset and for phase offset. Frame alignment is adjusted by averaging estimates of the phase offset over multiple tones within a frame, and then averaging that average estimated phase offset over multiple frames to produce a frame offset measurement. Frequency offset is derived from the constant rate of phase error variation in the received signal varies over a sequence of frames, based on which the sample frequency of the modem is adjusted. Phase offset is determined by averaging the phase offset over a plurality of tones within a frame, and integrating differences in this phase offset from frame to frame.

Abstract: Congestion is minimized on a desired port in an Ethernet bridge. A packet with a destination address and a source address is received on an incoming port. An address table is search to determine a destination port associated with the destination address. If the destination port is not determined by the search then flooding the packet on all of the ports except the desired port if the incoming port is determined to be equal to the desired port; and flooding the packet on all of the ports except the incoming port and the desired port if the incoming port is determined to be not equal to the desired port.

Abstract: Devices and methods are disclosed for detection and management of daisy-chain system topologies. A method is disclosed for auto-discovery and auto-enumeration. The method may be performed in a daisy-chain system of serially inter-connected devices. The method may include identifying each port of each device in a system of serially inter-connected devices, discovering each device in the system, and enumerating each device in the system.

Abstract: A device comprising transceiver logic and control logic coupled to the transceiver logic. The control logic is adapted to use the transceiver logic to broadcast a signal comprising either a Request-to-Send (RTS) signal or a Clear-to-Send-to-Self (CTS2S) signal to a plurality of other devices. The signal is adapted to cause the plurality of other devices to refrain from transmitting data. After at least some of the plurality of other devices have received the signal, the transceiver logic transmits at least part of another signal using beamforming techniques.

Abstract: A digital subscriber line (DSL) system that provides fast exit from an idle state includes a central office (CO) modem for communicating with a customer premises equipment (CPE) modem. Prior to entry into a low-power or idle state for the DSL link between the CO modem and the CPE modem, seamless rate adaptation is performed in order to improve the operating margin from that used in full-on operation, for example by selecting a reduced data rate. Transmission parameters, including data rate, and bits and gains, and corresponding to the improved operating margin are stored at the modems. Upon executing short initialization to return from the idle state, the stored transmission parameters are more likely to be adequate to meet current channel conditions, so the exchange of transmission parameters during short initialization is more likely to be avoided.

Abstract: A novel and useful mechanism for the detection and estimation of far-end cross talk (FEXT) caused by transmissions over adjacent wire pairs or cables. The detection and estimation technique of the invention can be used to identify FET impairments in Ethernet and DSL systems. The detection and estimation scheme is performed utilizing an adaptive FEXT canceller filter for detection purposes during normal operation of the system. FEXT filter tap coefficients are determined one at a time using a mechanism shared amongst all taps. Once adapted, the filter coefficients can be used to estimate FEXT strength and to determine spectral measurements of the FEXT impairment noise.

Abstract: The invention provides systems, devices, and methods for frequency hopping. In one method embodiment, the invention hops between frequencies by using the same channel to transmit data from a master to a slave, and from the slave to the master. One system embodiment provides an enhanced master coupled to an enhanced slave. In one device embodiment, the invention is a computer readable medium adapted to enable frequency hopping in a frequency band.

Abstract: One embodiment of the present invention includes a method for synchronizing packet production and receipt from a digital signal processor (DSP) with polled transmission opportunities in an IEEE 802.11e network. The method comprises producing a packet via the DSP and transmitting the packet from the DSP to a transmission device at a time that is substantially synchronized with a next polled transmission opportunity granted by an access point in an IEEE 802.11(e) network. The method also comprises time stamping the arrival of the packet at the transmission device and transmitting the packet from the transmission device.

Abstract: A method of determining indices for matrix codewords in a matrix codeword codebook. The matrix codewords are adapted for communicating information between a transmitter and a receiver. The method includes retrieving from temporary storage, an eigenmode representation for a communications channel, where the eigenmode representation is based upon on a received signal precoded by a first matrix codeword. The method also includes performing a test on multiple vector codewords to identify a first vector codeword among the multiple vector codewords, where the test includes determining a relationship between the first vector codeword and the representation of an eigenmode. The first vector codeword is associated with a first vector codeword index that identifies the first vector codeword. The method also includes generating a matrix codeword index associated with a second matrix codeword in the matrix codeword codebook.

Abstract: A novel apparatus for and method of estimating the cable length of an active network link. The cable diagnostics mechanism of the invention is particularly suited for use in estimating the length of Ethernet network between two edges when the link is active, i.e. data is being transmitted in both directions simultaneously and the transmission of test pulses is not possible. The cable length estimation mechanism of the present invention is based on a well-known property of the spectrum of the insertion loss of the cable, namely, the linear relationship between the attenuation of the cable at a given frequency in decibels and the cable length. Information characterizing this relationship is extracted and used to determine the length of the cable.

Abstract: A method of determining indicators for matrix codewords in a matrix codeword codebook, where the matrix codewords are adapted for communicating information between a transmitter and a receiver. The method includes providing a lookup table that is associated with multiple codewords that are associated with a codebook. The lookup table has m rows, and each row in the lookup table has a one-to-one correspondence with a codeword in the multiple codewords. Each row has p entries and each of the p entries holds a codeword indicator that identifies a codeword in the multiple codewords. The (i,j)th entry in the lookup table holds the codeword indicator identifying the jth most similar codeword to the codeword associated with the ith row according to a similarity metric, where 1?i?m and 1?j?p, and the m rows include a row k.

Abstract: One embodiment of the present invention includes a method for controlling a gain of a wideband signal. The method comprises adding a virtual channel to the wideband signal, the wideband signal comprising at least one channel. The method also comprises monitoring an output power associated with the wideband signal that includes the at least one channel and the virtual channel. The method further comprises setting a gain factor to achieve a predetermined output power of the wideband signal and amplifying the wideband signal based on the gain factor.