Title
Twin tree hierarchy: a regularized approach to construction of signature matrices for overloaded CDMA.
Abstract
Overloaded code division multiple access being the only means of the capacity extension for conventional code division multiple access accommodates more number of signatures than the spreading gain. Recently, ternary Signature Matrices with Orthogonal Subsets (SMOS) has been proposed, where the capacity maximization is 200%. The proposed multi-user detector using matched filter exploits the twin tree hierarchy of correlation among the subsets to guarantee the errorless recovery. In this paper, we feature the non-ternary version of SMOS (i.e., 2k-ary SMOS) of same capacity, where the binary alphabets in all the k constituent (orthogonal) subsets are unique. Unlike ternary, the tree hierarchy for 2k-ary SMOS is non-uniform. However, the errorless detection of the multi-user detector remains undeviated. For noisy transmission, simulation results show the error performance of the right child for each subset of 2k-ary to be significantly improved over the left. The optimality of the right child of the largest (Hadamard) subset is also discovered. At higher loading, for larger and smaller subsets the superiority is reported for the 2k-ary and ternary, respectively, and the counter-intuitive deviations observed for the lower loading scenarios are logically explained. For the overall capacity maximization being 150%, superiority is featured by the 2k-ary, but beyond, it becomes a conditional entity. Copyright (C) 2016 John Wiley & Sons, Ltd.
Year
DOI
Venue
2016
10.1002/wcm.2732
WIRELESS COMMUNICATIONS & MOBILE COMPUTING
Keywords
Field
DocType
overloaded CDMA,uniquely decodable codes,orthogonality,multiple access interference (MAI),twin tree hierarchy,decoder,bit error rate (BER)
Computer science,Matrix (mathematics),Algorithm,Orthogonality,Matched filter,Hierarchy,Code division multiple access,Hadamard transform,Detector,Binary number
Journal
Volume
Issue
ISSN
16.0
17.0
1530-8669
Citations 
PageRank 
References 
0
0.34
0
Authors
4
Name
Order
Citations
PageRank
Amiya Singh120.73
Poonam Singh2327.23
arash amini3184.06
Farokh Marvasti457372.71