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Cayley codes for multi-antenna differential modulation

Hassibi, Babak and Hochwald, Bertrand M. (2001) Cayley codes for multi-antenna differential modulation. In: Conference Record of the Thirty-Fifth Asilomar Conference on Signals, Systems and Computers, 2001. Vol.1. IEEE , Piscataway, NJ, pp. 232-235. ISBN 0-7803-7147-X.

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Multiple antenna differential modulation using unitary matrices requires no channel knowledge at the receiver, and so is ideal for use on wireless links where channel tracking is undesirable or infeasible, either because of rapid changes in the channel characteristics or because of limited system resources. Although this basic principle is well understood, it is not known how to generate good-performing constellations of unitary matrices, for any number of transmit and receive antennas and especially at high rates. We propose a class of Cayley codes that works with any number of antennas, and allows for polynomial-time near-maximum-likelihood decoding based on either successive nulling/cancelling or sphere decoding. The codes use the Cayley transform, which maps the highly nonlinear Stiefel manifold of unitary matrices to the linear space of skew-Hermitian matrices. This leads to a simple linear constellation structure in the Cayley transform domain and to an information-theoretic design criterion based on emulating a Cauchy random matrix. Simulations show that Cayley codes allow efficient and effective high-rate data transmission in multi-antenna communication systems without knowing the channel.

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Additional Information:© 2001 IEEE.
Record Number:CaltechAUTHORS:20150213-065942830
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:54801
Deposited By: Shirley Slattery
Deposited On:13 Feb 2015 22:32
Last Modified:10 Nov 2021 20:38

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