Motorola Corporation

Other

At&t Bell Laboratories

David D Falconer

Fuyun Ling

Eugene J Bruckert

Vedat M Eyuboglu

A coherent RAKE receiver utilizes a 'blind block' path gain estimation scheme, based on a maximum likelihood criterion, to estimate path gains in the receiver. It is 'blind' in that preliminary hard decisions on coded bits (i.e., coded bits from the corrupt transmitted signal) are not used. Instead, a form of soft decisions are used. It is a 'block' scheme in that the complex path gains are estimated for an isolated block, for example a block of B correlator outputs. The path gains varying with time are approximated to be linear in time such that the average path gain and the slope of the path gain per path can be utilized to estimate the path gain. The path gain estimation scheme overcomes the shortcomings of typical CDMA systems where there is no assurance of continuous transmission (except for full-rate 9600 b/s transmission) upon which to base a FIR filter-type prediction scheme.

Path gain estimation in a receiver

A method and apparatus is provided for transmitting spread spectrum signals. The transmitter receives data symbols. Subsequently, the transmitter splits each particular set of two received data symbols into a first and second array of data symbols according to either of two algorithms. The first algorithm including providing both data symbols of the particular set to the first and second array of data symbols and the second algorithm including providing one of the data symbols of the particular set to the first array of data symbols and the other of the data symbols of the particular set to the second array of data symbols. Subsequently, the transmitter determines particular channels to transmit the first and second array of data symbols by spreading the first and second array of data symbols with a predetermined length Walsh code. The transmitter accommodates a variable number of data channels by selecting a particular algorithm from a group consisting essentially of a first algorithm and a second algorithm and setting the predetermined length Walsh code in response to the particular algorithm selected.

Method and apparatus for accommodating a variable number of

A method and apparatus is provided for transmitting spread spectrum signals. The transmitter receives data bits at a particular rate. Subsequently, the transmitter encodes the received data bits at a predetermined encoding rate into data symbols. Subsequently, the transmitter derives predetermined length orthogonal codes from the data symbols. The transmitter accommodates variable received data bit rates by setting the predetermined encoding rate and the predetermined orthogonal code length in response to the received data bit rate. Subsequently, the transmitter spreads the derived orthogonal codes with a user PN spreading code. An alternative method and apparatus is provided for transmitting spread spectrum signals. The transmitter receives data bits at a particular rate. Subsequently, the transmitter encodes the received data bits at a predetermined encoding rate into data symbols. Subsequently, the transmitter determines a particular channel to transmit the data symbols by spreading the data symbols with a predetermined length orthogonal code. The transmitter accommodates variable received data bit rates by setting the predetermined encoding rate and the predetermined orthogonal code length in response to the received data bit rate.

Method and apparatus for providing high data rate traffic channels in a

A method and apparatus is provided for encoding and decoding. In encoding, bits (202) are encoded (204) into symbols (206) such that maximum likelihood decoding is facilitated. Groups of symbols (206) are translated by either interleaving by group each group within a block (208) and subsequently deriving an orthogonal code from each group (212) or deriving an orthogonal code from each group and subsequently interleaving by code each code within a block. In decoding, groups of samples (228, 229) are transformed by either generating metrics and index symbols (242) for each group of samples (232, 234, 236, 238, 240) and subsequently deinterleaving by group each group of metrics within a block (244) or deinterleaving by group each group of samples within a block and subsequently generating metrics and index symbols for each deinterleaved group of samples. Each metric represents the confidence that a group of samples is a particular orthogonal code. Subsequently, maximum likelihood decoding (266) generates an estimated bit (268) from the index symbols and metrics (260).

Method and apparatus for using orthogonal coding in a communication

A method and apparatus is provided for encoding and decoding. In encoding, bits (202) are encoded (204) into symbols (206) such that maximum likelihood decoding is facilitated. Groups of symbols (206) are translated by either interleaving by group each group within a block (208) and subsequently deriving an orthogonal code from each group (212) or deriving an orthogonal code from each group and subsequently interleaving by code each code within a block. In decoding, groups of samples (228, 229) are transformed by either generating metrics and index symbols (242) for each group of samples (232, 234, 236, 238, 240) are subsequently deinterleaving by group each group of metrics within a block (244) or deinterleaving by group each group of samples within a block and subsequently generating metrics and index symbols for each deinterleaved group of samples. Each metric represents the confidence that a group of samples is a particular orthogonal code. Subsequently, maximum likelihood decoding (266) generates an estimated bit (268) from the index symbols and metrics (260).

Asynchronous digital frequency shift keyed (FSK) signals are demodulated by using an autocorrelation type demodulator including digital integration. To this end, the autocorrelation function and digital integration are realized by generating integration increments, i.e., area increments, at the digital signal sampling points and accumulating them to obtain the integrated output. This is realized by turning to account a relationship between zero crossings of the received signal, zero crossings of a delayed version of the received signal and polarity of the product of the received signal and its delayed version relative to sampling points of the received digital signal. Specifically, the area increment in an n.sup.th sampling interval is determined by the time interval since the last zero crossing of the received signal before the n.sup.th sampling point, the time interval since the last zero crossing of the delayed signal before the n.sup.th sampling point and the polarity of the product signal at the n.sup.th sampling point.

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Nepean, Canada

David D Falconer