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UCLA Optical CDMA: Efficient Uncoordinated Asynchronous Multiple Access through Coding

User 1. Logical OR of input bits. User 2. +. User n. UCLA Optical CDMA: Efficient Uncoordinated Asynchronous Multiple Access through Coding. Single-User Decoding (SUD) allows an efficiency of 0.6931 or better. OR channel captures essence of optical multiple access. UCLA 06Q4. UCLA 06Q2.

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UCLA Optical CDMA: Efficient Uncoordinated Asynchronous Multiple Access through Coding

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  1. User 1 Logical OR of input bits User 2 + User n UCLA Optical CDMA: Efficient Uncoordinated Asynchronous Multiple Access through Coding Single-User Decoding (SUD) allows an efficiency of 0.6931 or better. OR channel captures essence of optical multiple access. UCLA 06Q4 UCLA 06Q2 UCLA Demonstration for September 05 Conventional OCDMA correlation receivers • Efficiency = (bits of useful information)/(number of received bits).

  2. The Z channel (right) describes how a single-user decoder sees other users as noise that flips some zeros to ones, but never vice versa. UCLA has designed novel nonlinear error control codes that transmit a low density of ones (minimizing their interference with other users) while still providing efficient reliable communication over the Z channel. Each user selects a random interleaver, which prevents receivers from accidentally decoding the wrong user. This system is completely asynchronous, requires no code assignment coordination, and has a large cardinality because the role of the spreading code is played by random interleavers, which are numerous. Encoder Interleaver + Other users De-Interleaver Decoder UCLA Optical CDMA: Single User Decoding-Codes for the Z-Channel

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