236,447 Hits in 3.2 sec

Non-Orthogonal Multiple Access (NOMA) for Cellular Future Radio Access

Yuya Saito, Yoshihisa Kishiyama, Anass Benjebbour, Takehiro Nakamura, Anxin Li, Kenichi Higuchi
2013 2013 IEEE 77th Vehicular Technology Conference (VTC Spring)  
To implement K-user multi-rate multi-power transmission in non-orthogonal multiple access systems with successive interference cancellation, a repeat accumulator code serially concatenated with a spreading  ...  A joint rate and power optimization (RPO) is proposed to maximize the sum rate with error free decoding.  ...  sum rate R à sum ¼ P K k¼1 1=ðq à k l à k Þ with error free decoding.  ... 
doi:10.1109/vtcspring.2013.6692652 dblp:conf/vtc/SaitoKBNLH13 fatcat:ggbwsbwd5rdrpm6p5c3tt2kuxm

Minimal letter frequency in n-th power-free binary words [chapter]

Roman Kolpakov, Gregory Kucherov
1997 Lecture Notes in Computer Science  
We also consider a generalization of n-th power-free words de ned through the notion of exponent: a word is x-th power-free for a real x, if it does not contain subwords of exponent x or more.  ...  We show that the minimal proportion of one letter in an n-th power-free binary word is asymptotically 1=n.  ...  Lemma 5 For every k 2 IN , w k is n-th power-free. Proof: We use induction over k. Clearly, w 1 is an n-th power-free word. Assume by contradiction that for some k 2, w k?  ... 
doi:10.1007/bfb0029978 fatcat:eu4gqvarljhmvmqxkaczyfxtye

Spectral coding performance under free space optical medium

A.K Rahman, N Julai, M. Jusoh, C.B.M Rashidi, S.A Aljunid, Anuar M.S, M.F Talib, Nurdiani Zamhari, S.K Sahari, K.F. Tamrin, Rudiyanto P. Jong, D.N.A Zaidel (+3 others)
2019 Indonesian Journal of Electrical Engineering and Computer Science  
The result shows that ZCC code improve the performance of conventional code in term of number of users, power received and data bit rate.</span>  ...  Due to this high class characteristic, the code improves the performance of the conventional code in free space optical environment.  ...  ERROR b b Th Th P Q Q                     2 0 1 2 2 2 0 1 2( ) 1 ( (2 )).( ( )) ( ) ( ) 2 b b ERROR b b Th Th P X k X Q Q                               ... 
doi:10.11591/ijeecs.v14.i1.pp290-294 fatcat:dwqp7ejdrjgwthbsoglhlt3nvy

Orthogonal space–time block codes for free-space IM/DD optical links

M. Premaratne, F.-C. Zheng
2007 Electronics Letters  
A generalised framework for applying orthogonal STBCs for free-space IM=DD optical links is presented.  ...  Use of orthogonal space-time block codes (STBCs) with multiple transmitters and receivers can improve signal quality.  ...  unit matrix and kxk 2 ¼ (x 1 2 þ x 2 2 þ Á Á Á þ x K 2 ) .  ... 
doi:10.1049/el:20073712 fatcat:7saqtnxsf5eyjpsbk2up5ohteq

Analytical Studies of Fragmented-Spectrum Multi-Level OFDM-CDMA Technique in Cognitive Radio Networks [article]

Farhad Akhoundi, Saeed Sharifi-Malvajerdi, Omid Poursaeed, Jawad A. Salehi
2016 arXiv   pre-print
Given this information, some real-valued multi-level orthogonal codes, which are orthogonal codes with values of {±1,±2,±3,±4, ... }, are provided for emerging new users, i.e., cognitive radio users.  ...  spreading power of each CR user on all free subcarriers.  ...  Therefore, in transmission phase (τ ≤ t ≤ T ), CR users spread their power using their specified codes on free subcarriers, and transmit without interfering with primary users.  ... 
arXiv:1604.07124v1 fatcat:obvyzswitffphljmj6ztwfoqom

Soft-Decision Decoding of Punctured Convolutional Codes in Asynchronous-CDMA Communications Under Perfect Phase-Tracking Conditions

Vidhyacharan Bhaskar
2006 International Journal of Wireless Information Networks  
Soft-decision decoding of punctured convolutional codes is considered in this paper. The upper bounds with Viterbi decoding are derived and plotted for the various punctured codes considered.  ...  In this paper, the performance of punctured convolutional codes of short constraint lengths is discussed.  ...  The minimum free distance and distance spectra of the rate-5/9 code are d=5 and c i ; i ¼ d; d þ 1; d þ 2; . . .  ... 
doi:10.1007/s10776-006-0025-2 fatcat:v7ktc2xoxbdpnn2vcakwwllmfu

Photonic Microwave Frequency Measurement With High-Coding-Efficiency Digital Outputs and Large Measurement Range

Bing Lu, Wei Pan, Xihua Zou, Lianshan Yan, Bin Luo
2013 IEEE Photonics Journal  
After power detection and decision operation, an N-bit digital result in the form of binary code is obtained for microwave frequency measurement within the range of 2 Â FSR.  ...  Index Terms: Instantaneous frequency measurement (IFM), microwave photonics, optical filter array, free spectral range (FSR).  ...  m =FSR þ k Þ 2 ; ð1 k N À 1Þ (4) and the power ratio for the N-th optical filter can be written as R N ðf m Þ ¼ 1 þ cosðf m =FSRÞ 2 : (5) Based on the power ratios, an analog-to-digital conversion can  ... 
doi:10.1109/jphot.2013.2280517 fatcat:et4jyj5phjebnjxgo5cho3vmiq

Power allocation and code construction for space–time turbo trellis codes with partial CSI feedback

J. Kingsley, A. Allan, Y. Li, B. Vucetic, J. Yuan
2008 Electronics Letters  
Conventional space -time turbo trellis coding (STTuTC) schemes allocate transmit power equally to the available antennas.  ...  This scheme is referred to as STTuTC with dynamic transmit power allocation (STTuTC/DTPA). The optimum four-state constituent code and power allocation are presented.  ...  The interleaver is assumed to be uniform: FER UB E S N 0 ÀnT P D HðD K Þ Q nT ;DK ðA; w 1 ; w 2 Þ ð 8Þ where Q n T , D K (A, w 1 , w 2 ) is the code power allocation function averaged within region D K  ... 
doi:10.1049/el:20080616 fatcat:z5jnxbhorjhqvgyics2pbjsgsa

On Isodual Cyclic Codes over Finite Fields and Finite Chain Rings: Monomial Equivalence [article]

Aicha Batoul, Kenza Guenda, T. Aaron Gulliver, Nuh Aydin
2016 arXiv   pre-print
Several constructions of isodual cyclic codes and self-dual codes are given.  ...  This paper present the construction cyclic isodual codes over finite fields and finite chain rings. These codes are monomially equivalent to their dual.  ...  Since q is an odd prime power, by [3, Proposition 4.2], there exists a primitive 2 a -th root of unity in R * if and only if there exists a primitive 2 a -th root of unity in F q .  ... 
arXiv:1303.1870v2 fatcat:bnazkgm43ffkrhzbx7nbjzr4h4

Reconfigurable Parallel Turbo Decoder Design for Multiple High-Mobility 4G Systems

Cheng-Hung Lin, Chun-Yu Chen, En-Jui Chang, An-Yeu Wu
2013 Journal of Signal Processing Systems  
systems, this paper presents a dual-standard turbo decoder design with the following three techniques. 1) Circular parallel decoding reduces decoding latency and improves throughput rate. 2) Collision-free  ...  The parallel interleaver is collision-free when it satisfies p t þ jW ð Þ W " # 6 ¼ p t þ kW ð Þ W " # ; ð7Þ where 0 ≦ t<W, and 0 ≦ j, k<P.  ...  s 0 ð Þ Á g k s 0 ; s ð ÞÁb kþ1 ðsÞ ð Þ P s 0 ;s ð Þ)u k ¼0 a k s 0 ð Þ Á g k s 0 ; s ð ÞÁb kþ1 ðsÞ ð Þ 0 B @ 1 C A; ð5aÞ a kþ1 ðsÞ ¼ X all s 0 a k s 0 ð Þ Á g k s 0 ; s ð Þ ð ; ð5bÞ b k s 0 ð Þ ¼ X all  ... 
doi:10.1007/s11265-013-0735-5 fatcat:vg6t4esffbf2jdjdu7hjh3435y

Non-cooperative games for spreading code optimization, power control and receiver design in wireless data networks [article]

Stefano Buzzi, H. Vincent Poor
2007 arXiv   pre-print
throughput to transmit power.  ...  The case considered is that in which each user is allowed to vary its transmit power, spreading code, and uplink receiver in order to maximize its own utility, which is here defined as the ratio of data  ...  a packet from the k-th user is received error-free.  ... 
arXiv:0705.0783v1 fatcat:rgfimfjvnbcqfpy2zwvmy3abze

The REAL Approach to Generate Orthogonal Complementary Codes for Next Generation CDMA Systems

Hsiao-Hwa CHEN
2006 Interdisciplinary Information Sciences  
First, implementation of an interference-free CDMA will never be possible unless using complementary code sets, such as the OC code sets.  ...  In other words, all traditional spreading codes working on an one-code-per-user basis are not useful for implementation of an MAI-free and MIfree CDMA system.  ...  Fig. 4 . 4 Block diagram of a K-user CDMA system using the OC codes (a flock of the element codes fc k1 ; c k2 ; . . . ; c kM g is assigned to the k-th user for 1 k K), where each user employs M element  ... 
doi:10.4036/iis.2006.147 fatcat:ieggmwzjgzfunposbdakon62sq

Joint source-channel coding and power adaptation for energy efficient wireless video communications

Fan Zhai, Yiftach Eisenberg, Thrasyvoulos N. Pappas, Randall Berry, Aggelos K. Katsaggelos
2005 Signal processing. Image communication  
Specifically, we present a framework of joint source-channel coding and power adaptation, where error resilient source coding, channel coding, and transmission power adaptation are jointly designed to  ...  In addition to both types of channel coding, we also compensate for channel errors by adapting the transmission power used to send each packet.  ...  The Viterbi upper bound for the bit error probability is p b p 1 G P 1 d¼d free c d p d ; where d free is the free distance of the convolutional code, p d is the probability that the wrong path at distance  ... 
doi:10.1016/j.image.2005.02.002 fatcat:ocfgsfbcrfhbdf2ycf5hbk72ze

A stochastic non-cooperative game for energy efficiency in wireless data networks [article]

Stefano Buzzi, H. Vincent Poor, Daniela Saturnino
2007 arXiv   pre-print
Building on a recent paper by the first two authors, wherein a non-cooperative game for spreading-code optimization, power control, and receiver design has been proposed to maximize the ratio of data throughput  ...  to transmit power for each active user, a stochastic algorithm is here described to perform adaptive implementation of the said non-cooperative game.  ...  from the k-th user is received error-free.  ... 
arXiv:0705.3013v1 fatcat:lneemukpj5dxtoikvnziy37vse

A characterization of power-free morphisms

Michel Leconte
1985 Theoretical Computer Science  
A morphism is power-free if it is kth power-free for every k > 1.  ...  A word is called kth power-free if it does not contain any non-empty factor uk. A morphism is kth power-free if it preserves kth power-free words.  ...  If i, = ik-l = 2 and n = 3, then w is not k-th power-free. Proof.  ... 
doi:10.1016/0304-3975(85)90213-0 fatcat:mmdamt562febdbdb4teqf63ib4
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