Title :
Orthogonal codes for robust low-cost communication
Author :
Zhang, Wenyi ; Mitra, Urbashi
Author_Institution :
Ming Hsieh Dept. of Electr. Eng., Southern California Univ., Los Angeles, CA
fDate :
Jan. 27 2008-Feb. 1 2008
Abstract :
Orthogonal coding schemes, known to asymptotically achieve the capacity per unit cost (CPUC) for single-user ergodic memoryless channels with a zero-cost input symbol, are investigated for single-user compound memoryless channels, which exhibit uncertainties in their input-output relationships. A minimax formulation is adopted to attain robustness. First, a class of achievable rates per unit cost (ARPUC) is derived, and its utility is demonstrated through several representative case studies. Second, when the channel uncertainty satisfies a convexity property, optimization is performed over the class of ARPUC through utilizing results of minimax robustness. The resulting CPUC lower bound indicates the ultimate performance of the orthogonal coding scheme, and coincides with the CPUC under certain restrictive conditions. Finally, still under the convexity property, it is shown that the CPUC can generally be achieved, through utilizing a so-called mixed strategy in which an orthogonal code contains an appropriate composition of different nonzero-cost input symbols.
Keywords :
channel capacity; memoryless systems; orthogonal codes; achievable rates per unit cost; capacity per unit cost; orthogonal codes; robust low-cost communication; single-user ergodic memoryless channels; Channel capacity; Costs; Decoding; Memoryless systems; Minimax techniques; Phase estimation; Robustness; Statistics; Time measurement; Uncertainty;
Conference_Titel :
Information Theory and Applications Workshop, 2008
Conference_Location :
San Diego, CA
Print_ISBN :
978-1-4244-2670-6
DOI :
10.1109/ITA.2008.4601093