California Institute of Technology

Victoria Kostina

Michelle Effros

Recep Can Yavas

Farshad Lahouti

Mohammadreza Ebrahimi

Shuqing Chen

Systems and methods in accordance with various embodiments of the invention perform lossless source coding. Nested code structures are utilized to perform Random Access Source Coding (RASC), where the number of active encoders is initially unknown. Decoders can attempt to source decode using a number of Slepian-Wolf decoders corresponding to an estimated number of sources. Multiple source encoders are configured to receive start messages and transmit portions of codewords, selected by source encoding data from sources to remove redundancy, until an end of epoch message is received.

Systems and methods for performing lossless source coding

Communication systems and methods in accordance with various embodiments of the invention employ a rateless coding strategy in which an encoder utilizes codewords located within a restricted subset of a multi-dimensional sphere. In one embodiment, a transmitter is configured to encode message data as symbols using a rateless code until an end of epoch message is received, where the rateless code comprises a set of codewords characterized in that they are located within a restricted subset of a multi-dimensional sphere. A receiver receives observed symbols and at each of a predetermined set of decode times, determines whether a decoding rule is satisfied. When the decoding rule is satisfied, the receiver decodes at least one message using the rateless code and transmits an end of epoch message.

Systems and methods for communicating using random codewords located within a restricted subset of a multi-dimensional sphere

Coded access communication systems and methods are described. In one embodiment, the communication system includes a plurality of transmitters that transmit signals via a random access channel, where each transmitter includes: an encoder that encodes data bits using a two-layer code including an inner medium access control code and and an outer error correcting code; and a modulator that modulates each encoded bit for transmission via the random access channel. In addition, the communication system includes a receiver including: a demodulator configured to demodulate received signals and provide input signals to the decoder; and a decoder configured to iteratively decode data bits received from the plurality of transmitters using message passing between an inner medium access control layer and an outer coding layer to jointly perform contention resolution and decoding.

Coded random access mechanism for communication networks

Systems and methods for random access communication in accordance with various embodiments of the invention are described in which receivers can handle uncoordinated transmissions of a large and unknown number of transmitters. Communication systems in accordance with many embodiments of the invention include a plurality of transmitters that encode message data as symbols using a rateless code. During transmission, the transmitters receive feedback messages at a predetermined set of potential decoding times until an end of epoch message is received. A receiver transmits at least one start of epoch message and, at each of a predetermined set of decoding times, determines whether a decoding rule is satisfied. When the decoding rule is satisfied, the receiver can decode at least one message from observed symbols based upon the rateless code. The receiver can end the transmission epoch by transmitting an end of epoch message.

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Pasadena, CA, United States of America

Victoria Kostina