Broadcom Corporation

Christopher R Jones

Kelly Brian Cameron

Thomas J Quigley

Henry Samueli

Jonathan S Min

Lisa Voigt Denney

Fang Lu

Feng Chen

Sean Francis Nazareth

Ba-Zhong Shen

Hau Thien Tran

Steven T Jaffe

Theodore F Rabenko

James C H Thi

John D Horton, Jr

Thomas A Hughes, Jr

Thomas Ashford Hughes, Jr

A number of features for enhancing the performance of a communication system, in which data is transmitted between a base station and a plurality of subscriber stations located different distances from the base station, are presented. The power transmission level, slot timing, and equalization of the subscriber stations are set by a ranging process. Data is transmitted by the subscriber stations in fragmented form. Various measures are taken to make transmission from the subscriber stations robust. The uplink data transmission is controlled to permit multiple access from the subscriber stations.

Robust techniques for upstream communication between subscriber stations and a base station

A method for synchronizing receivers that receive turbo encoded signals to a received signal. Turbo encoding may enable signals to be decoded at a much lower signal to noise ratio than previously practical. A traditional method of synchronizing a receiver to an incoming signal is to use a slicer to determine a received symbol and then to compare the determined symbol to the incoming waveform, in order to adjust the phase of the slicer with respect to the incoming signal. At signal low levels, at which turbo encoded signals may be decoded, this slicing method may be prone to errors that may disrupt the synchronization of the receiver to the incoming signal. By replacing the slicer by a Viterbi decoder with zero traceback (i.e., one which does not consider future values of the signal only past values) a prediction as to what the incoming signal is can be made. Because the Viterbi decoder can consider past signal values it can predict the present symbol being received with higher reliability than by using a slicer, which considers only the present value of the incoming signal.

Viterbi slicer for turbo codes

Compensating for noise in a wireless communication system

Methods to compensate for noise in a wireless communication system

A method for parallel concatenated (Turbo) encoding and decoding. Turbo encoders receive a sequence of input data tuples and encode them. The input sequence may correspond to a sequence of an original data source, or to an already coded data sequence such as provided by a Reed-Solomon encoder. A turbo encoder generally comprises two or more encoders separated by one or more interleavers. The input data tuples may be interleaved using a modulo scheme in which the interleaving is according to some method (such as block or random interleaving) with the added stipulation that the input tuples may be interleaved only to interleaved positions having the same modulo-N (where N is an integer) as they have in the input data sequence. If all the input tuples are encoded by all encoders then output tuples can be chosen sequentially from the encoders and no tuples will be missed. If the input tuples comprise multiple bits, the bits may be interleaved independently to interleaved positions having the same modulo-N and the same bit position. This may improve the robustness of the code. A first encoder may have no interleaver or all encoders may have interleavers, whether the input tuple bits are interleaved independently or not. Modulo type interleaving also allows decoding in parallel.

Parallel concatenated code with soft-in soft-out interactive turbo decoder

A method for parallel concatenated (Turbo) encoding and decoding. Turbo encoders receive a sequence of input data tuples and encode them. The input sequence may correspond to a sequence of an original data source, or to an already coded data sequence such as provided by a Reed-Solomon encoder. A turbo encoder generally comprises two or more encoders separated by one or more interleavers. The input data tuples may be interleaved using a modulo scheme in which the interleaving is according to some method (such as block or random interleaving) with the added stipulation that the input tuples may be interleaved only to interleaved positions having the same modulo&#x2212;N (where N is an integer) as they have in the input data sequence. If all the input tuples are encoded by all encoders then output tuples can be chosen sequentially from the encoders and no tuples will be missed. If the input tuples comprise multiple bits, the bits may be interleaved independently to interleaved positions having the same modulo&#x2212;N and the same bit position. This may improve the robustness of the code. A first encoder may have no interleaver or all encoders may have interleavers, whether the input tuple bits are interleaved independently or not. Modulo type interleaving also allows decoding in parallel.

A number of features for enhancing the performance of a wireless communication system, in which data is transmitted between a central node and a plurality of subscriber nodes located remotely with respect to the central node, are presented. The power transmission level, slot timing, and equalization of the subscriber nodes are set by a ranging process. Data is transmitted by the subscriber nodes in fragmented form. Various measures are taken to make transmission from the subscriber nodes robust. The uplink data transmission is controlled to permit multiple access from the subscriber nodes.

Data packet fragmentation in a wireless communication system

A method for synchronizing receivers that receive turbo encoded signals to a received signal. Turbo encoding may enable signals to be decoded at a much lower signal to noise ratio than previously practical. A traditional method of synchronizing a receiver to an incoming signal is to use a slicer to determine a received symbol and then to compare the determined symbol to the incoming waveform, in order to adjust the phase of the slicer with respect to the incoming signal. At signal low levels, at which turbo encoded signals may be decoded, this slicing method may be prone to errors that may disrupt the synchronization of the receiver to the incoming signal. By replacing the slicer by a Viterbi decoder with zero traceback (i.e. one which does not consider future values of the signal only past values) a prediction as to what the incoming signal is can be made. Because the Viterbi decoder can consider past signal values it can predict the present symbol being received with higher reliability than by using a slicer, which considers only the present value of the incoming signal.

Synchronization module using a Viterbi slicer for a turbo decoder

A method for parallel concatenated (Turbo) encoding and decoding. Turbo encoders receive a sequence of input data tuples and encode them. The input sequence may correspond to a sequence of an original data source, or to an already coded data sequence such as provided by a Reed-Soloman encoder. A turbo encoder generally comprises two or more encoders separated by one or more interleavers. The input data tuples may be interleaved using a modulo scheme in which the interleaving is according to some method (such as block or random interleaving) with the added stipulation that the input tuples may be interleaved only to interleaved positions having the same modulo-N (where N is an integer) as they have in the input data sequence. If all the input tuples are encoded by all encoders then output tuples can be chosen sequentially from the encoders and no tuples will be missed. If the input tuples comprise multiple bits, the bits may be interleaved independently to interleaved positions having the same modulo-N and the same bit position. This may improve the robustness of the code. A first encoder may have no interleaver or all encoders may have interleavers, whether the input tuple bits are interleaved independently or not. Modulo type interleaving also allows decoding in parallel.

Quasi error free method and system are presented for encoding and decoding information using turbo codes as an inner code in conjunction with an algebraic outer code linked by an interleaver. This combination of outer algebraic code and turbo inner code linked by an interleaver, which has a guaranteed minimum Depth between symbols output from the interleaver, can produce a quasi error free performance in systems utilizing Turbo-Codes without an increase in bandwidth.

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Newport Beach, CA, United States of America

Christopher R Jones