Baseband systems

HELECTRICITY H04Electric communication H04LTRANSMISSION OF DIGITAL INFORMATION

H04L25/00Baseband systems

H04L25/02Details; Arrangements for supplying electrical power along data transmission lines H04L25/0202Channel estimation H04L25/0204of multiple channels H04L25/0206of each channel individually H04L25/0208of the composite channel H04L25/021Estimation of channel covariance H04L25/0212of impulse response H04L25/0214of a single coefficient H04L25/0216with estimation of channel length H04L25/0218with detection of nulls H04L25/022of frequency response H04L25/0222Estimation of channel variability H04L25/0224using sounding signals H04L25/0226sounding signals per se H04L25/0228with direct estimation from sounding signals H04L25/023with extension to other symbols H04L25/0232by interpolation between sounding signals H04L25/0234by non-linear interpolation H04L25/0236using estimation of the other symbols H04L25/0238using blind estimation H04L25/024channel estimation algorithms H04L25/0242using matrix methods H04L25/0244with inversion H04L25/0246with factorisation H04L25/0248Eigen-space methods H04L25/025using least-mean-square [LMS] method H04L25/0252using third or higher order statistics H04L25/0254using neural network algorithms H04L25/0256Channel estimation using minimum mean square error criteria H04L25/0258Channel estimation using zero-forcing criteria H04L25/026Arrangements for coupling transmitters, receivers or transceivers to transmission lines; Line drivers H04L25/0262Arrangements for detecting the data rate of an incoming signal H04L25/0264Arrangements for coupling to transmission lines H04L25/0266Arrangements for providing Galvanic isolation H04L25/0268with modulation and subsequent demodulation H04L25/027specifically for telegraph signals H04L25/0272Arrangements for coupling to multiple lines H04L25/0274Arrangements for ensuring balanced coupling H04L25/0276Arrangements for coupling common mode signals H04L25/0278Arrangements for impedance matching H04L25/028Arrangements specific to the transmitter end H04L25/0282Provision for current-mode coupling H04L25/0284Arrangements to ensure DC-balance H04L25/0286Provision of wave shaping within the driver H04L25/0288the shape being matched to the transmission line H04L25/029Provision of high-impedance states H04L25/0292Arrangements specific to the receiver end H04L25/0294Provision for current-mode coupling H04L25/0296Arrangements to ensure DC-balance H04L25/0298Arrangement for terminating transmission lines H04L25/03Shaping networks in transmitter or receiver H04L25/03006Arrangements for removing intersymbol interference H04L25/03012operating in the time domain H04L25/03019adaptive H04L25/03025using a two-tap delay line H04L25/03031using only passive components H04L25/03038with a non-recursive structure H04L25/03044using fractionally spaced delay lines or combinations of fractionally integrally spaced taps H04L25/0305using blind adaptation H04L25/03057with a recursive structure H04L25/03063using fractionally spaced delay lines or combinations of fractionally and integrally spaced taps H04L25/0307using blind adaptation H04L25/03076not using decision feedback H04L25/03082Theoretical aspects of adaptive time domain methods H04L25/03089Theory of blind algorithms, recursive or not H04L25/03095Theory of fractional equalisers, recursive or not H04L25/03101Theory of the Kalman algorithm H04L25/03108Theory of recursive equalisers, other than Kalman H04L25/03114non-adaptive H04L25/03121using a two-tap delay line H04L25/03127using only passive components H04L25/03133with a non-recursive structure H04L25/0314using fractionally spaced delay lines or combinations of fractionally integrally spaced taps H04L25/03146with a recursive structure H04L25/03152Theoretical aspects of non-adaptive time domain methods H04L25/03159operating in the frequency domain H04L25/03165using neural networks H04L25/03171Arrangements involving maximum a posteriori probability [MAP] detection H04L25/03178Arrangements involving sequence estimation techniques H04L25/03184Details concerning the metric H04L25/03191in which the receiver makes a selection between different metrics H04L25/03197methods of calculation involving metrics H04L25/03203Trellis search techniques H04L25/0321Sorting arrangements therefor H04L25/03216using the M-algorithm H04L25/03222using the T-algorithm H04L25/03229with state-reduction using grouping of states H04L25/03235with state-reduction using feedback filtering H04L25/03242Methods involving sphere decoding H04L25/03248Arrangements for operating in conjunction with other apparatus H04L25/03254Operation with other circuitry for removing intersymbol interference H04L25/03261with impulse-response shortening filters H04L25/03267with decision feedback equalisers H04L25/03273with carrier recovery circuitry H04L25/0328with interference cancellation circuitry H04L25/03286with channel-decoding circuitry H04L25/03292with channel estimation circuitry H04L25/03299with noise-whitening circuitry H04L25/03305Joint sequence estimation and interference removal H04L25/03312Arrangements specific to the provision of output signals H04L25/03318Provision of soft decisions H04L25/03324Provision of tentative decisions H04L25/03331Arrangements for the joint estimation of multiple sequences H04L25/03337Arrangements involving per-survivor processing H04L25/03343Arrangements at the transmitter end H04L25/03821Inter-carrier interference cancellation [ICI] H04L25/03828Arrangements for spectral shaping; Arrangements for providing signals with specified spectral properties H04L25/03834using pulse shaping H04L25/0384Design of pulse shapes H04L25/03847Shaping by selective switching of amplifying elements H04L25/03853Shaping by digital methods other than look up tables or up/down converters H04L25/03859shaping using look up tables for partial waveforms H04L25/03866using scrambling H04L25/03872Parallel scrambling or descrambling H04L25/03878Line equalisers; line build-out devices H04L25/03885adaptive H04L25/03891Spatial equalizers H04L25/03898codebook-based design H04L25/03904cooperative design H04L25/0391construction details of matrices H04L25/03917according to the size of the codebook H04L25/03923according to the rank H04L25/03929with layer mapping H04L25/03936multi-resolution codebooks H04L25/03942switching between different codebooks H04L25/03949equalizer selection or adaptation based on feedback H04L25/03955in combination with downlink estimations H04L25/03961design criteria H04L25/03968mean-square error [MSE] H04L25/03974throughput maximization H04L25/0398Restoration of channel reciprocity H04L25/03987Equalisation for sparse channels H04L25/03993Noise whitening H04L25/05Electric or magnetic storage of signals before transmitting or retransmitting for changing the transmission rate H04L25/06Dc level restoring means Bias distortion correction decision circuits providing symbol by symbol detection H04L25/061providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components H04L25/062Setting decision thresholds using feedforward techniques only H04L25/063Setting decision thresholds using feedback techniques only H04L25/064Subtraction of the threshold from the signal, which is then compared to a supplementary fixed threshold H04L25/065Binary decisions H04L25/066Multilevel decisions, not including self-organising maps H04L25/067providing soft decisions H04L25/068by sampling faster than the nominal bit rate H04L25/069by detecting edges or zero crossings H04L25/08Modifications for reducing interference Modifications for reducing effects due to line faults; Receiver end arrangements for detecting or overcoming line faults H04L25/085Arrangements for reducing interference in line transmission systems H04L25/10Compensating for variations in line balance H04L25/12Compensating for variations in line impedance H04L25/14Channel dividing arrangements in which a single bit stream is divided between several baseband channels and reassembled at the receiver H04L25/20Repeater circuits Relay circuits H04L25/202using mechanical devices H04L25/205using tuning forks or vibrating reeds H04L25/207using electromagnetic switches H04L25/22Repeaters for converting two wires to four wires Repeaters for converting single current to double current H04L25/24Relay circuits using discharge tubes or semiconductor devices H04L25/242with retiming H04L25/245for start-stop signals H04L25/247for synchronous signals H04L25/26Circuits with optical sensing means H04L25/38Synchronous or start-stop systems H04L25/40Transmitting circuits Receiving circuits H04L25/42using mechanical distributors H04L25/44using relay distributors H04L25/45using electronic distributors H04L25/46using tuning forks or vibrating reeds H04L25/49using code conversion at the transmitter using predistortion using insertion of idle bits for obtaining a desired frequency spectrum using three or more amplitude levels; Baseband coding techniques specific to data transmission systems H04L25/4902Pulse width modulation; Pulse position modulation H04L25/4904using self-synchronising codes H04L25/4906using binary codes H04L25/4908using mBnB codes H04L25/491using 1B2B codes H04L25/4912using CMI or 2-HDB-3 code H04L25/4915using pattern inversion or substitution H04L25/4917using multilevel codes H04L25/4919using balanced multilevel codes H04L25/4921using quadrature encoding H04L25/4923using ternary codes H04L25/4925using balanced bipolar ternary codes H04L25/4927using levels matched to the quantisation levels of the channel H04L25/493by transition coding H04L25/497by correlative coding H04L25/4975Correlative coding using Tomlinson precoding, Harashima precoding , Trellis precoding or GPRS