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		<title><![CDATA[ Communications, IEEE Transactions on - new TOC ]]></title>
		<link>http://ieeexplore.ieee.org</link>
		<description>TOC Alert for Publication# 26 </description>
		<year>2013</year>
		<month>May      </month>
		<day>21</day>
		<item>
			<title><![CDATA[Table of contents]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514801]]></link>
			<description><![CDATA[ ]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514801]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>c1</startPage>
			<endPage>c4</endPage>
			<fileSize>84</fileSize>
			<authors><![CDATA[]]></authors>
		</item>
		<item>
			<title><![CDATA[Staff List]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514802]]></link>
			<description><![CDATA[ ]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514802]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>c2</startPage>
			<endPage>c2</endPage>
			<fileSize>77</fileSize>
			<authors><![CDATA[]]></authors>
		</item>
		<item>
			<title><![CDATA[Advanced Information of Parity Bits for Decoding Short Linear Block Codes Using the A* Algorithm]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461030]]></link>
			<description><![CDATA[The A* algorithm for decoding linear block codes is known to be an efficient tree-search method for decoding short linear block codes. We propose to employ the early acquired information of some parity bits to speed up the tree search. Analysis for the number of required information bits for obtaining the parity bits is provided. In addition, two versions of the modified A* algorithm which take advantage of the advanced information of parity bits are provided. Simulation results show that there is advantage in reducing the number of search tree edges in each proposed version as compared with two existing A* algorithms which do not consider the early information of parity bits.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461030]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1201</startPage>
			<endPage>1211</endPage>
			<fileSize>877</fileSize>
			<authors><![CDATA[Chang, Chia-Fu;Lin, Tien-Yu;Tai, Chao-Liang;Lin, Mao-Chao;]]></authors>
		</item>
		<item>
			<title><![CDATA[An Efficient ML Decoder for Tail-Biting Codes Based on Circular Trap Detection]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461031]]></link>
			<description><![CDATA[Tail-biting codes are efficient coding techniques to eliminate the rate loss in conventional known-tail convolutional codes at a cost of increased complexity in decoders. In addition, tail-biting trellis representation of block codes makes the trellis-based maximum likelihood (ML) decoder desirable for implementation. Circular Viterbi algorithm (CVA) is introduced to decode the tail-biting codes for its decoding efficiency. However, its decoding process suffers from circular traps, which degrade the decoding efficiency. In this paper, we propose an efficient checking rule for the detection of circular traps. Based on this rule, a novel maximum likelihood (ML) decoding algorithm for tail-biting codes is presented. On tail-biting trellis, computational complexity and memory consumption of this decoder are significantly reduced comparing to other available ML decoders, such as the two-phase ML decoder. To further reduce the decoding complexity, we propose a new near-optimal decoding algorithm based on a simplified trap detection strategy. The performance of the above algorithms is validated with simulation.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461031]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1212</startPage>
			<endPage>1221</endPage>
			<fileSize>870</fileSize>
			<authors><![CDATA[Wang, Xiaotao;Qian, Hua;Xiang, Weidong;Xu, Jing;Huang, Hao;]]></authors>
		</item>
		<item>
			<title><![CDATA[Grobner Bases for Lattices and an Algebraic Decoding Algorithm]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466341]]></link>
			<description><![CDATA[In this paper we present Grobner bases for lattices given in a general form, including integer and non-integer lattices. Grdot{o}bner bases for binary linear codes were introduced by Borges-Quintana et al. . We extend their work to non-binary group block codes. Then, given a lattice &#x039b; and its associated label code L, which is a group code, we define an ideal for L. A Grobner basis is assigned to &#x039b; as the Grobner basis of its label code L. Since the associated label code for integer and non-integer lattices are group codes, the assigned Grobner bases can be obtained for both cases. Using this Grobner basis an algebraic decoding algorithm is introduced. We provide an example of the decoding method for a lower dimension lattice. We explain that the complexity of this decoding method depends on the division algorithm and show this decoding method has polynomial time complexity. Experiments for some versions of root lattices (E_7 and E_8) show that for low SNR the performance of these lattices is near to the lower bounds given in .]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466341]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1222</startPage>
			<endPage>1230</endPage>
			<fileSize>534</fileSize>
			<authors><![CDATA[Aliasgari, Malihe;Sadeghi, Mohammad-Reza;Panario, Daniel;]]></authors>
		</item>
		<item>
			<title><![CDATA[Signal Uncertainty in Spectrum Sensing for Cognitive Radio]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466335]]></link>
			<description><![CDATA[The inability to perfectly know the system noise properties to infinite precision, referred to as noise uncertainty, results in noise power calibration errors that have been proven to impose fundamental limitations on the detection performance of any spectrum sensing (signal detection) method in cognitive radio networks. In this work we argue that the inability of cognitive radio users to perfectly know beforehand the primary signals that might be present in the sensed band and their properties, referred to as signal uncertainty in this work, also results in an additional detection performance degradation. The noise uncertainty consequences have widely been studied, verified experimentally and distilled into tractable mathematical models. However, the potential effects of the particular primary signal properties on the resulting detection probability of generic spectrum sensing algorithms, such as energy detection, have not been taken into account in the analysis and performance evaluation of spectrum sensing in cognitive radio networks. In this context, this work develops a mathematical model for signal uncertainty and, based on such model, analyzes the impact of signal uncertainty on the resulting detection performance of spectrum sensing, with and without noise uncertainty, and compares the practical consequences of both degrading effects.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466335]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1231</startPage>
			<endPage>1241</endPage>
			<fileSize>521</fileSize>
			<authors><![CDATA[Lopez-Benitez, Miguel;Casadevall, Fernando;]]></authors>
		</item>
		<item>
			<title><![CDATA[Generalized Mean Detector for Collaborative Spectrum Sensing]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466333]]></link>
			<description><![CDATA[In this paper, a unified generalized eigenvalue based spectrum sensing framework referred to as Generalized mean detector (GMD) has been introduced. The generalization of the detectors namely (i) the eigenvalue ratio detector (ERD) involving the ratio of the largest and the smallest eigenvalues; (ii) the Geometric mean detector (GEMD) involving the ratio of the largest eigenvalue and the geometric mean of the eigenvalues and (iii) the Arithmetic mean detector (ARMD) involving the ratio of the largest and the arithmetic mean of the eigenvalues is explored. The foundation of the proposed unified framework is based on the calculation of exact analytical moments of the random variables of test statistics of the respective detectors. In this context, we approximate the probability density function (PDF) of the test statistics of the respective detectors by Gaussian/Gamma PDF using the moment matching method. Finally, we derive closed-form expressions to calculate the decision threshold of the eigenvalue based detectors by exchanging the derived exact moments of the random variables of test statistics with the moments of the Gaussian/Gamma distribution function. The performance of the eigenvalue based detectors is compared with the traditional detectors such as energy detector (ED) and cyclostationary detector (CSD) and validate the importance of the eigenvalue based detectors particularly over realistic wireless cognitive environments. Analytical and simulation results show that the GEMD and the ARMD yields considerable performance advantage in realistic spectrum sensing scenarios. Moreover, our results based on proposed simple and tractable approximation approaches are in perfect agreement with the empirical results.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466333]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1242</startPage>
			<endPage>1253</endPage>
			<fileSize>713</fileSize>
			<authors><![CDATA[Shakir, Muhammad Zeeshan;Rao, Anlei;Alouini, Mohamed-Slim;]]></authors>
		</item>
		<item>
			<title><![CDATA[Cooperation-Based Dynamic Spectrum Leasing via Multi-Winner Auction of Multiple Bands]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451072]]></link>
			<description><![CDATA[In this paper, we study a cooperation-based dynamic spectrum leasing mechanism via multi-winner auction of multiple bands. Based on a second-price auction mechanism, the primary users independently conduct auctions to determine winners who are then granted access to leased bands and prices for those bands. Before auctions, each secondary user jointly chooses bands which they want to lease and generates bids for those bands with a limited transmit power budget. To this end, we determine the feasibility conditions for band selection and for power and time allocation. Further, we propose a low complexity bidding algorithm that iteratively selects a band and calculates the bid for that band. For the paying price among winners after auctions, a multi-objective optimization problem is considered. We derive Pareto optimal solutions and propose paying schemes that prioritize the objectives with pre-defined weighting rules. In addition, the payment and secondary utility are investigated with regard to the number of winners. Simulation results show that secondary users achieve significantly increased utility as more winners are chosen, while primary users are guaranteed a non-negative benefit from spectrum leasing. The power consumed by the secondary users for cooperative transmission is compared for the proposed paying schemes.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451072]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1254</startPage>
			<endPage>1263</endPage>
			<fileSize>765</fileSize>
			<authors><![CDATA[Lim, Hyoung-Jin;Song, Moon-Gun;Im, Gi-Hong;]]></authors>
		</item>
		<item>
			<title><![CDATA[Novel Pilot-Assisted Spectrum Sensing for OFDM Systems by Exploiting Statistical Difference Between Subcarriers]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6459479]]></link>
			<description><![CDATA[This paper presents a novel pilot-assisted spectrum sensing technique for orthogonal frequency-division multiplexing (OFDM) systems. The main idea is based upon the physical nature that subcarriers carrying pilots or payload data have different first-order and second-order statistical properties. These differences vanish when the spectrum of interest is unoccupied. Therefore, the decision of spectrum availability can be formed based upon these differences, which can be explored through employment of frequency-domain differential operations. Thanks to the differential operations, the proposed technique has less sensitivity of the noise power uncertainty problem caused by imperfect hardware. Performance of the proposed technique is analytically formulated in terms of probability of false alarm (PFA) and probability of detection (PD). Computer simulations are carried out to elaborate the analytical results. It is shown that the second-order statistics based proposed technique outperforms the conventional pilot-assisted technique up to 7 dB. Moreover, it is shown that the first-order statistics based proposed technique outperforms the second-order statistics based proposed technique for small normalized Doppler shifts (&#x02264; 0.013). However, the second-order statistics based proposed technique offers better performance for larger normalized Doppler shifts.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6459479]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1264</startPage>
			<endPage>1276</endPage>
			<fileSize>747</fileSize>
			<authors><![CDATA[Lu, Zhengwei;Ma, Yi;Cheraghi, Parisa;Tafazolli, Rahim;]]></authors>
		</item>
		<item>
			<title><![CDATA[Relay Channel with Orthogonal Components and Structured Interference Known at the Source]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457364]]></link>
			<description><![CDATA[A relay channel with orthogonal components in which the destination is affected by an interference signal that is non-causally available only at the source is studied. The interference signal has structure in that it is produced by another transmitter communicating with its own destination. Moreover, the interferer is not willing to adjust its communication strategy to minimize the interference. Knowledge of the interferer's signal may be acquired by the source, for instance, by exploiting HARQ retransmissions on the interferer's link. The source can then utilize the relay not only for communicating its own message, but also for cooperative interference mitigation at the destination by informing the relay about the interference signal. Proposed transmission strategies are based on partial decode-and-forward (PDF) relaying and leverage the interference structure. Achievable schemes are derived for discrete memoryless models, Gaussian and Ricean fading channels. Furthermore, optimal strategies are identified in some special cases. Finally, numerical results bring insight into the advantages of utilizing the interference structure at the source, relay or destination.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457364]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1277</startPage>
			<endPage>1289</endPage>
			<fileSize>661</fileSize>
			<authors><![CDATA[Bakanoglu, Kagan;Erkip, Elza;Simeone, Osvaldo;Shitz, Shlomo Shamai;]]></authors>
		</item>
		<item>
			<title><![CDATA[On The Throughput-Reliability Tradeoff for Amplify-and-Forward Cooperative Systems]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451074]]></link>
			<description><![CDATA[This paper investigates the throughput-reliability tradeoff (TRT) for dual-hop amplify-and-forward relay systems with one source, one destination, and multiple relays, and its relationship with the diversity-multiplexing tradeoff (DMT). The TRT was proposed in the context of MIMO block fading channels to reveal the interplay between the signal-to-noise ratio (SNR), rate R, and outage probability that are not accessible through the DMT. The contributions of this paper include the calculation of the TRT expressions for two classes of amplify-and-forward protocols: the slotted amplify-and-forward and the non-orthogonal amplify-and-forward. Based on the derived expressions, relationships between the SNR, rate and outage probability are explored. The relationship between the TRT and the DMT is investigated. One of the goals of the TRT is to predict the slope and offset of the outage vs. SNR set of curves parameterized by different rates. We verify the accuracy of the TRT predictions in the context of amplify-and-forward relays.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451074]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1290</startPage>
			<endPage>1303</endPage>
			<fileSize>645</fileSize>
			<authors><![CDATA[Li, Jun;Chen, Wen;Nosratinia, Aria;Yuan, Jinhong;]]></authors>
		</item>
		<item>
			<title><![CDATA[OFDM AF Relaying Under I/Q Imbalance: Performance Analysis and Baseband Compensation]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461032]]></link>
			<description><![CDATA[We analyze the outage performance of half-duplex amplify-and-forward relaying in an OFDM system with MRC detection in the presence of I/Q imbalance and compare it with that of the direct transmission mode. Both analytical and numerical results demonstrate that the direct mode can outperform the amplify-and-forward mode even under moderate levels of uncompensated I/Q imbalance. The cross-over I/Q imbalance levels are determined analytically to be inversely proportional to the cube of the signal constellation size. In addition, we present a low-complexity receiver-based digital baseband I/Q imbalance compensation scheme for the amplify-and-forward mode and analyze its EVM performance. Furthermore, we derive accurate analytical approximations for the EVM performance as a function of relay location and I/Q imbalance level with and without compensation.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461032]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1304</startPage>
			<endPage>1313</endPage>
			<fileSize>787</fileSize>
			<authors><![CDATA[Mokhtar, Mohamed;Gomaa, Ahmad;Al-Dhahir, Naofal;]]></authors>
		</item>
		<item>
			<title><![CDATA[On the Delivery Probability of Two-Hop Relay MANETs with Erasure Coding]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457366]]></link>
			<description><![CDATA[This paper focuses on the delivery probability performance in a two-hop relay mobile ad hoc network (MANET) with erasure coding. Available works in this line either considered a simple extreme case of achieving the delivery probability 1, or assumed a simple traffic pattern with only one source-destination pair, or studied a very special MANET scenario (i.e., the sparsely distributed MANET) by assuming that whenever two nodes meet together they can transmit to each other. Obviously, such models cannot be applied for an accurate delivery probability analysis in the general MANETs where the interference, medium contention and traffic contention issues are of significant importance. In this paper, a general finite-state absorbing Markov chain theoretical framework is first developed to model the complicated message spreading process in the challenging MANETs. Based on the theoretical framework, closed-form expressions are further derived for the corresponding message delivery probability under any given message lifetime and message size, where all the above important issues in MANETs are carefully incorporated into analysis. As verified through extensive simulation studies, the new framework can be used to accurately predict the message delivery probability behavior and characterize its relationship with the message size, replication factor and node density there.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457366]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1314</startPage>
			<endPage>1326</endPage>
			<fileSize>618</fileSize>
			<authors><![CDATA[Liu, Jiajia;Jiang, Xiaohong;Nishiyama, Hiroki;Kato, Nei;]]></authors>
		</item>
		<item>
			<title><![CDATA[Distributed Dynamic Frequency Allocation in Fractional Frequency Reused Relay Based Cellular Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6403860]]></link>
			<description><![CDATA[To increase frequency efficiency in cellular communication networks, this paper describes a cell coloring based distributed frequency allocation approach (C-DFA) for all kinds of cellular networks. C-DFA has high computational efficiency and is simpler to realize than other distributed approaches. Building on C-DFA, a distributed dynamic fractional frequency allocation (DDFFA) algorithm is designed for IEEE 802.16j supported Relay Based Cellular Networks (RBCN). It is shown that: a) C-DFA can better realize frequency efficiency and network resilience compared to centralized traditional distributed frequency allocation approach. b) DDFFA can significantly increase frequency efficiency to provide high capacity and throughput to the RBCN though at the cost of extra computation and BS-BS communication. The evaluations and analysis are based on moderate and high user congestion RBCN scenarios.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6403860]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1327</startPage>
			<endPage>1336</endPage>
			<fileSize>2720</fileSize>
			<authors><![CDATA[Mei, Haibo;Bigham, John;Jiang, Peng;Bodanese, Eliane;]]></authors>
		</item>
		<item>
			<title><![CDATA[Energy Based Performance Evaluation of Passive EPC Gen 2 Class 1 RFID Systems]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466334]]></link>
			<description><![CDATA[This paper analyzes performance of RFID networks that are based on passive tags using EPC Gen2 Class1 communication protocol. For the first time, all the main factors impacting tag read efficiency and read latency are considered - inclusive of MAC layer collision, link layer packet loss and the impact of the use of energy harvesting in passive tags. Specifically, the impact of tag {duty cycling} due to limited harvested energy is considered - a first in the analysis of RFID systems, to the best of our knowledge.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466334]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1337</startPage>
			<endPage>1348</endPage>
			<fileSize>1059</fileSize>
			<authors><![CDATA[Hessar, Farzad;Roy, Sumit;]]></authors>
		</item>
		<item>
			<title><![CDATA[Delay-Optimal Distributed Scheduling in Multi-User Multi-Relay Cellular Wireless Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457370]]></link>
			<description><![CDATA[We propose a novel scheme for delay-optimal scheduling in multi-user multi-relay cellular wireless networks. The cell area is divided into several sectors, each serviced by an individual relay station (RS). In order to have simultaneous transmissions by the users in neighbouring sectors, we assume that users of each individual sector use separate set of orthogonal channels to communicate with the RS and the base station (BS). Moreover, a separate orthogonal channel is shared among relays for transmission to the BS. For uplink communication, users are allowed to choose between two modes of transmission, namely, direct transmission mode and relayed transmission mode through a simple transmission mode selection algorithm. Users are allocated fractions of the time-slot for the first phase of transmission (from the users to the BS and the RSs) in a time-division multiple access (TDMA) fashion. For the second phase of transmission (from the RSs to the BS), each RS is allocated a fraction of the time-slot. We model the problem of end-to-end (e2e) delay-optimal scheduling as an infinite-horizon average reward Markov decision process (MDP) for users and relays in two separate stages. An online learning approach is then employed to solve the problem in a distributed manner for both users and relays in each phase of transmission. The proposed online stochastic learning solution converges to the optimal solution almost surely (with probability 1) under some realistic conditions. Simulation results show that the proposed approach outperforms the conventional scheduling schemes.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457370]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1349</startPage>
			<endPage>1360</endPage>
			<fileSize>773</fileSize>
			<authors><![CDATA[Moghadari, Mohammad;Hossain, Ekram;Le, Long Bao;]]></authors>
		</item>
		<item>
			<title><![CDATA[On the Generalization of Natural Type Selection to Multiple Description Coding]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466337]]></link>
			<description><![CDATA[Natural type selection was originally proposed by Zamir and Rose for universal single description coding. In this paper, we generalize this principle to universal multiple description coding (MDC). Two schemes based on random codebooks are proposed: one is of fixed distortion and the other is of fixed weight. Their operational sum-rate-distortion functions are derived, which coincide with the EGC (El Gamal-Cover) sum-rate bound if the parameters of the schemes are optimized. It is also shown that in both schemes the joint type of reconstruction codewords can be used to improve the rate-distortion (R-D) performance. Based on our theoretical results, a practical universal scheme is proposed by leveraging the MDC methods based on low-density generator matrix (LDGM) codes. The performance of this scheme is compared experimentally with the EGC bound, which shows its effectiveness.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466337]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1361</startPage>
			<endPage>1373</endPage>
			<fileSize>1035</fileSize>
			<authors><![CDATA[Fan, Yuhua;Wang, Jia;Sun, Jun;Chen, Jun;]]></authors>
		</item>
		<item>
			<title><![CDATA[Normalized Adaptive Channel Equalizer Based on Minimal Symbol-Error-Rate]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466344]]></link>
			<description><![CDATA[Existing minimum-symbol-error-rate equalizers were derived based on the symbol-error-rate objective function. Due to the complexity of the objective function the derivation is not straightforward. In this paper we present a new approach to derive the minimum-symbol-error-rate adaptive equalizers. The problem is formulated as minimizing the norm between two subsequent parameter vectors under the constraint of symbol-error-rate minimization. The constrained optimization problem then is solved with the Lagrange multiplier method, which results in an adaptive algorithm with normalization. Simulation results show that the proposed algorithm outperforms the existing adaptive minimum-symbol-error-rate equalizer in convergence speed and steady-state performance.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466344]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1374</startPage>
			<endPage>1383</endPage>
			<fileSize>622</fileSize>
			<authors><![CDATA[Gong, Meiyan;Chen, Fangjiong;Yu, Hua;Lu, Zhaohua;Hu, Liujun;]]></authors>
		</item>
		<item>
			<title><![CDATA[The Effect of Macrodiversity on the Performance of Maximal Ratio Combining in Flat Rayleigh Fading]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451073]]></link>
			<description><![CDATA[The performance of maximal ratio combining (MRC) in Rayleigh channels with co-channel interference (CCI) is well-known for receive arrays which are co-located. Recent work in network MIMO, edge-excited cells and base station collaboration is increasing interest in macrodiversity systems. Hence, in this paper we consider the effect of macrodiversity on MRC performance in Rayleigh fading channels with CCI. We consider the uncoded symbol error rate (SER) as our performance measure of interest and investigate how different macrodiversity power profiles affect SER performance. This is the first analytical work in this area. We derive approximate and exact symbol error rate results for M-QAM/BPSK modulations and use the analysis to provide a simple power metric. Numerical results, verified by simulations, are used in conjunction with the analysis to gain insight into the effects of the link powers on performance.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451073]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1384</startPage>
			<endPage>1392</endPage>
			<fileSize>640</fileSize>
			<authors><![CDATA[Basnayaka, Dushyantha A.;Smith, Peter J.;Martin, Philippa A.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Power-Reductive Precoding for the Transmission of Correlated Information Sequences]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451077]]></link>
			<description><![CDATA[In communication theory, the conventional role of precoding is to reshape a spectrally flat sequence of data symbols in favor of a particular inter-symbol interference (ISI) channel such that signal-to-noise power ratio (SNR) is maximized. In contrast, in this paper a novel precoding technique is devised to exploit a particular property of the information source rather than the channel. Specifically, we focus on the scenario where the source sequence has an inherent correlation that is known a priori, and design a precoding filter that attempts to reduce the average power of the resulting transmit symbol sequences. The proposed precoding technique is thus termed power-reductive precoding (PRP). This reduction of average transmit power accrues without changing the amplitude of the original sequence and thus can be treated as a system gain. An apparent drawback of this approach is the intentional ISI introduced by the precoding filter, which may lessen the minimum distance among legitimate sequences. Nevertheless, we show that even if the loss associated with the minimum distance penalty is properly taken into account, the achievable error rate versus SNR can be made superior to the case without precoding.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451077]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1393</startPage>
			<endPage>1403</endPage>
			<fileSize>645</fileSize>
			<authors><![CDATA[Tanahashi, Makoto;Ochiai, Hideki;]]></authors>
		</item>
		<item>
			<title><![CDATA[On the Bivariate Nakagami-m Cumulative Distribution Function: Closed-Form Expression and Applications]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457369]]></link>
			<description><![CDATA[In this paper, we derive exact closed-form expressions for the bivariate Nakagami-m cumulative distribution function (CDF) with positive integer fading severity index m in terms of a class of hypergeometric functions. Particularly, we show that the bivariate Nakagami-m CDF can be expressed as a finite sum of elementary functions and bivariate confluent hypergeometric &#x03a6;_3 functions. Direct applications which arise from the proposed closed-form expression are the outage probability (OP) analysis of a dual-branch selection combiner in correlated Nakagami-m fading, or the calculation of the level crossing rate (LCR) and average fade duration (AFD) of a sampled Nakagami-m fading envelope.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457369]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1404</startPage>
			<endPage>1414</endPage>
			<fileSize>2241</fileSize>
			<authors><![CDATA[Lopez-Martinez, F.Javier;Morales-Jimenez, David;Martos-Naya, Eduardo;Paris, Jose F.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Reduced-Complexity Approx-Log-MAP and Max-Log-MAP Soft PSK/QAM Detection Algorithms]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461035]]></link>
			<description><![CDATA[In this paper, we propose to reduce the complexity of both the Approx-Log-MAP algorithm as well as of the Max-Log-MAP algorithm conceived for generalized PSK/QAM detection, where only a reduced-size subset of the PSK/QAM constellation points is taken into account for producing a single soft-bit output. Although the detectors of Gray-labelled low-order PSK/QAM schemes generally produce near-horizontal EXIT curves, our proposed detectors exploit the a priori LLRs gleaned from a channel decoder in order to retain the optimum detection capability for all PSK/QAM constellations. Furthermore, we demonstrate in this paper that the widely applied MIMO schemes including V-BLAST and STBC, which invoke the proposed soft PSK/QAM detectors may also benefit from our reduced-complexity design. Our simulation results confirm that a near-capacity performance may be achieved by the proposed detectors at a substantially reduced detection complexity.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461035]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1415</startPage>
			<endPage>1425</endPage>
			<fileSize>568</fileSize>
			<authors><![CDATA[Xu, Chao;Liang, Dandan;Sugiura, Shinya;Ng, Soon Xin;Hanzo, Lajos;]]></authors>
		</item>
		<item>
			<title><![CDATA[User Scheduling for Cooperative Base Station Transmission Exploiting Channel Asymmetry]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457371]]></link>
			<description><![CDATA[We study low-signalling overhead scheduling for downlink coordinated multi-point (CoMP) transmission with multi-antenna base stations (BSs) and single-antenna users. By exploiting the asymmetric channel feature, i.e., the pathloss differences towards different BSs, we derive a metric to judge orthogonality among users only using their average channel gains, based on which we propose a semi-orthogonal scheduler that can be applied in a two-stage transmission strategy. Simulation results demonstrate that the proposed scheduler performs close to the semi-orthogonal scheduler with full channel information, especially when each BS is with more antennas and the cell-edge region is large. Compared with other overhead reduction strategies, the proposed scheduler requires much less training overhead to achieve the same cell-average data rate.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457371]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1426</startPage>
			<endPage>1435</endPage>
			<fileSize>1330</fileSize>
			<authors><![CDATA[Han, Shengqian;Yang, Chenyang;Bengtsson, Mats;]]></authors>
		</item>
		<item>
			<title><![CDATA[Energy and Spectral Efficiency of Very Large Multiuser MIMO Systems]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457363]]></link>
			<description><![CDATA[A multiplicity of autonomous terminals simultaneously transmits data streams to a compact array of antennas. The array uses imperfect channel-state information derived from transmitted pilots to extract the individual data streams. The power radiated by the terminals can be made inversely proportional to the square-root of the number of base station antennas with no reduction in performance. In contrast if perfect channel-state information were available the power could be made inversely proportional to the number of antennas. Lower capacity bounds for maximum-ratio combining (MRC), zero-forcing (ZF) and minimum mean-square error (MMSE) detection are derived. An MRC receiver normally performs worse than ZF and MMSE. However as power levels are reduced, the cross-talk introduced by the inferior maximum-ratio receiver eventually falls below the noise level and this simple receiver becomes a viable option. The tradeoff between the energy efficiency (as measured in bits/J) and spectral efficiency (as measured in bits/channel use/terminal) is quantified for a channel model that includes small-scale fading but not large-scale fading. It is shown that the use of moderately large antenna arrays can improve the spectral and energy efficiency with orders of magnitude compared to a single-antenna system.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457363]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1436</startPage>
			<endPage>1449</endPage>
			<fileSize>797</fileSize>
			<authors><![CDATA[Ngo, Hien Quoc;Larsson, Erik G.;Marzetta, Thomas L.;]]></authors>
		</item>
		<item>
			<title><![CDATA[On the Exact BER of Bit-Wise Demodulators for One-Dimensional Constellations]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466342]]></link>
			<description><![CDATA[The optimal bit-wise demodulator for M-ary pulse amplitude modulation (PAM) over the additive white Gaussian noise channel is analyzed in terms of uncoded bit-error rate (BER). The BER analysis is based on studying the bit patterns that form a labeling. New closed-form BER expressions for 4-PAM with any labeling are developed. Moreover, closed-form BER expressions for 11 out of 23 possible bit patterns for 8-PAM are presented, which enable us to obtain the BER for 8-PAM with some of the most popular labelings, including the binary reflected Gray code and the natural binary code. Numerical results show that, regardless of the labeling, there is no difference between the optimal demodulator and the symbol-wise demodulator for any BER of practical interest (below 0.1).]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466342]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1450</startPage>
			<endPage>1459</endPage>
			<fileSize>1094</fileSize>
			<authors><![CDATA[Ivanov, Mikhail;Brannstrom, Fredrik;Alvarado, Alex;Agrell, Erik;]]></authors>
		</item>
		<item>
			<title><![CDATA[An Analysis of Band-limited Communication Systems from Amplifier Efficiency and Distortion Perspective]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457368]]></link>
			<description><![CDATA[Considering growing concerns toward green communications, not only their bandwidth efficiency but also their power consumption is expected to gain increasing importance for future communication systems. A power amplifier (PA) is one of the most power consuming analog devices at the transmitter in communication systems and a precise estimation of the power consumption at the transmitter circuit requires the knowledge of its efficiency that depends on the distribution of input signal envelope and the amount of input back-off. In this paper, we develop a simple analytical model that can be used for estimating achievable efficiency of a linear PA as well as the amount of resulting nonlinear distortion for a given modulated signal exclusively from its envelope distribution. Based on this model, the trade-off relationships between the efficiency and signal-to-distortion power ratio for several spectrally efficient linear modulations are examined. It is also shown that in some special cases of Gaussian input and memoryless nonlinearity PA models, the results can be represented in simple closed-form expressions.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6457368]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1460</startPage>
			<endPage>1472</endPage>
			<fileSize>1110</fileSize>
			<authors><![CDATA[Ochiai, Hideki;]]></authors>
		</item>
		<item>
			<title><![CDATA[Inter-Session Network Coding with Strategic Users: A Game-Theoretic Analysis of the Butterfly Network]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466332]]></link>
			<description><![CDATA[We analyze inter-session network coding in a wired network using game theory. We assume that users are selfish and act as strategic players to maximize their own utility, which leads to a resource allocation game among users. In particular, we study a butterfly network, where a bottleneck link is shared by network coding and routing flows. We assume that network coding is performed using pairwise XOR operations. We prove the existence of Nash equilibrium for a wide range of utility functions. We also show that the number of Nash equilibria can be large (even infinite) for certain choices of parameters. This is in sharp contrast to a similar game setting with traditional packet forwarding, where the Nash equilibrium is always unique. We characterize the worst-case efficiency bound, i.e., the Price-of-Anarchy (PoA), compared to an optimal and cooperative network design. We show that by using a discriminatory pricing scheme which charges encoded and forwarded packets differently, we can improve the PoA in comparison with the case where a single pricing scheme is used. However, even when a discriminatory pricing scheme is used, the PoA is still worse than for the case when network coding is not applied. This implies that, although inter-session network coding can improve performance compared to routing, it is much more sensitive to users' strategic behavior.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466332]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1473</startPage>
			<endPage>1484</endPage>
			<fileSize>877</fileSize>
			<authors><![CDATA[Mohsenian-Rad, Hamed;Huang, Jianwei;Wong, Vincent W.S.;Jaggi, Sidharth;Schober, Robert;]]></authors>
		</item>
		<item>
			<title><![CDATA[Max-Flow Min-Cost Routing in a Future-Internet with Improved QoS Guarantees]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6459492]]></link>
			<description><![CDATA[A Constrained Multicommodity Maximum-Flow-Minimum-Costrm} routing algorithm is presented. The algorithm computes maximum-flow routings for all smooth unicast traffic demands within the Capacity Region of a network subject to routing cost constraints. The edge cost can be a distance, reliability, congestion or an energy metric. It is shown that every network has a finite Bandwidth-Cost capacity. The Bandwidth-Distance and the Bandwidth-Energy capacities are explored. The routing algorithm requires the formulation of two Linear Programs (LPs). The first LP finds a multicommodity Maximum-Flow, when the flows are constrained to a sub-graph of the network to enforce cost constraints. The second LP minimizes the routing cost, given that the maximum-flow is fixed. A related Constrained Multicast-Max-Flow-Min-Cost algorithm is also presented, to maximize the throughput of a multicast tree using network coding, subject to routing cost constraints. These algorithms have polynomial-time solutions, whereas traditional multipath routing algorithms can be NP-Hard. The addition of routing cost constraints can significantly reduce the size of the LPs, resulting in faster solutions, with lower edge utilizations and with higher energy efficiencies. The application of these algorithms to route aggregated video streams from cloud data centers in a Future-Internetrm} network, with improved throughput, energy-efficiency and QoS guarantees is presented.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6459492]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1485</startPage>
			<endPage>1497</endPage>
			<fileSize>882</fileSize>
			<authors><![CDATA[Szymanski, Ted H.;]]></authors>
		</item>
		<item>
			<title><![CDATA[On the Use of Cooperative Physical Layer Network Coding for Energy Efficient Routing]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451075]]></link>
			<description><![CDATA[In this paper, we focus on energy efficient routing in wireless ad hoc networks. We exploit modulo combining of continuous-time signals arriving at a receiving node from a number of synchronized transmitting nodes and introduce a cooperative physical layer network coding (CPLNC) scheme. To demonstrate the effectiveness of the proposed scheme in reducing energy consumption, we propose two routing algorithms that utilize CPLNC as a basic building block. Through analysis, we show that with sufficiently long packets, the proposed algorithms can achieve energy saving gains of up to 37% and 62% with respect to the conventional shortest-path routing algorithm in regular line and grid networks, respectively, using less number of hops. We incorporate CPLNC into two major energy efficient routing algorithms and derive threshold distances that enable the current node to intelligently decide whether it should use CPLNC or point to point transmission to the next hop. Simulation results confirm that the proposed and the modified algorithms based on CPLNC outperform their conventional counterparts in terms of achieving significant energy saving gains in networks of randomly distributed nodes.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451075]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1498</startPage>
			<endPage>1509</endPage>
			<fileSize>585</fileSize>
			<authors><![CDATA[Akhtar, Auon Muhammad;Nakhai, Mohammad Reza;Aghvami, A.Hamid;]]></authors>
		</item>
		<item>
			<title><![CDATA[Error Control for Local Broadcasting in Heterogeneous Wireless Ad Hoc Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451070]]></link>
			<description><![CDATA[Local (single-hop) broadcasting is widely employed in distributed protocols (e.g., neighbor discovery, local information exchange in distributed network optimization and gossip-based algorithms) in wireless ad hoc networks. The performance of local broadcasting is characterized by the mean number of neighbors and the probability distribution of the number of neighbors of a broadcasting node. In this paper, we study the performance of local broadcasting in heterogeneous wireless ad hoc networks in which inter-system interference dominates signal reception quality, considering general fading distributions of both the desired signal and the interfering signals. In addition, we investigate the impacts of different error control techniques (e.g., simple retransmission, Chase combining, and incremental redundancy) on the performance of local broadcasting. The increase in the mean number of neighbors of a broadcasting node with respect to the number of retransmissions of a message is clarified, facilitating QoS provisioning in reliable local broadcasting in interference-limited heterogeneous wireless ad hoc networks.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451070]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1510</startPage>
			<endPage>1519</endPage>
			<fileSize>411</fileSize>
			<authors><![CDATA[Ao, Weng Chon;Chen, Kwang-Cheng;]]></authors>
		</item>
		<item>
			<title><![CDATA[A Modified Hard Core Point Process for Analysis of Random CSMA Wireless Networks in General Fading Environments]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461033]]></link>
			<description><![CDATA[For spectrum sharing and avoidance of mutual interference, carrier-sense multiple access (CSMA) protocols are very popular in distributed wireless networks. CSMA protocols aim to maximize the spatial frequency reuse while limiting the mutual interference and outage. The hard core point process (HCPP) is a very popular tool for modeling and analysis of random CSMA networks. However, the traditional HCPP suffers from the node intensity (and hence the interference) underestimation flaw. Therefore, we propose a modified hard core point process to mitigate this flaw. The proposed modified HCPP is generalized for any fading environment. To this end, we derive a closed-form expression for the intensity of simultaneously active transmitters in a random wireless CSMA network. Then, we derive a closed-form expression for approximating the outage probability experienced by a generic receiver in the network, and subsequently, use it to obtain the transmission capacity of the network. Finally, we show the existence of an optimal carrier-sensing threshold for the CSMA protocol that maximizes the transmission capacity of the network. Simulation results validate the analysis and also provide interesting insights into the design of practical CSMA networks.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461033]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1520</startPage>
			<endPage>1534</endPage>
			<fileSize>1004</fileSize>
			<authors><![CDATA[ElSawy, Hesham;Hossain, Ekram;]]></authors>
		</item>
		<item>
			<title><![CDATA[On the Power and Offset Allocation for Rate Adaptation of Spatial Multiplexing in Optical Wireless MIMO Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451079]]></link>
			<description><![CDATA[In this paper, we consider resource allocation method in the visible light communication. It is challenging to achieve high data rate due to the limited bandwidth of the optical sources. In order to increase the spectral efficiency, we design a suitable multiple-input multiple-output (MIMO) system utilizing spatial multiplexing based on singular value decomposition and adaptive modulation. More specifically, after explaining why the conventional allocation method in radio frequency MIMO channels cannot be applied directly to the optical intensity channels, we theoretically derive a power allocation method for an arbitrary number of transmit and receive antennas for optical wireless MIMO systems. Based on three key constraints: the nonnegativity of the intensity-modulated signal, the aggregate optical power budget, and the bit error rate requirement, we propose a novel method to allocate the optical power, the offset value, and the modulation size. Based on some selected simulation results, we show that our proposed allocation method gives a better spectral efficiency at the expense of an increased computational complexity in comparison to a simple method that allocates the optical power equally among all the data streams.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451079]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1535</startPage>
			<endPage>1543</endPage>
			<fileSize>492</fileSize>
			<authors><![CDATA[Park, Ki-Hong;Ko, Young-Chai;Alouini, Mohamed-Slim;]]></authors>
		</item>
		<item>
			<title><![CDATA[NLOS UV Communications Using M-ary Spectral-Amplitude-Coding]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461162]]></link>
			<description><![CDATA[We present an M-ary spectral amplitude code (SAC) modulation technique to improve the performance of free-space optical (FSO) communication systems. Although this approach can be used in any dispersive FSO system, in this paper we focus on non-line of sight (NLOS) ultraviolet (UV) systems relying on atmospheric scattering. Spectral amplitude encoding is applied on a broadband UV source using the same code families for the M-ary alphabet as used previously in SAC optical code division multiple access (OCDMA) systems. A differential structure using two photomultiplier tubes is utilized in conjunction with various demodulation algorithms to decode the received signal. Intersymbol interference (ISI), received beam divergence and shot noise are considered as the main factors limiting the system performance. An upper bound on the bit error probability is presented and compared with simulation results for various geometries and for different code parameters. The maximum bit rate for a fixed bit error probability is calculated in terms of the link length, and results for different alphabet sizes are shown. By sacrificing spectral efficiency without becoming more susceptible to ISI, the proposed system can support higher rates and longer distances for the same performance compared with on-off keying systems.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461162]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1544</startPage>
			<endPage>1553</endPage>
			<fileSize>1965</fileSize>
			<authors><![CDATA[Noshad, Mohammad;Brandt-Pearce, Maite;Wilson, Stephen G.;]]></authors>
		</item>
		<item>
			<title><![CDATA[A Passive Optical Network with Shared Transceivers for Dynamical Resource Allocation]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466343]]></link>
			<description><![CDATA[This paper presents a new passive optical network (PON) architecture that applies an optical multicast capable switch (OMS) to direct wavelengths to a set of PON branches and enables them to share the transceivers in the central office (CO) on demand. The OMS is composed of fiber splitters and switching gates, and by controlling the on-off gates the wavelengths at the inputs can reach any outputs of the OMS. Through the OMS configuration, logical PONs are dynamically formed according to changing traffic patterns, and traffic is further scheduled in the time domain within each logical PON. The proposed network achieves network resource sharing without requiring tunable transceivers or wavelength filters, and without changing deployed network devices in the field or at the user end. Analysis and experimental study results show the efficiency of resource sharing and demonstrate the concept of resource sharing among PON branches.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466343]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1554</startPage>
			<endPage>1561</endPage>
			<fileSize>2948</fileSize>
			<authors><![CDATA[Zhou, Luying;Xu, Zhaowen;Huang, Qirui;Cheng, Xiaofei;Yeo, Yong-Kee;Xu, Shao;]]></authors>
		</item>
		<item>
			<title><![CDATA[Delay-Limited Source and Channel Coding of Quasi-Stationary Sources over Block Fading Channels: Design and Scaling Laws]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6427623]]></link>
			<description><![CDATA[In this paper, delay-limited transmission of quasi-stationary sources over block fading channels is considered. Considering distortion outage probability as the performance measure, two source and channel coding schemes with power adaptive transmission are presented. The first one is optimized for fixed rate transmission, and hence enjoys simplicity of implementation. The second one is a high performance scheme, which also benefits from optimized rate adaptation with respect to source and channel states. In high SNR regime, the performance scaling laws in terms of outage distortion exponent and asymptotic outage distortion gain are derived, where two schemes with fixed transmission power and adaptive or optimized fixed rates are considered as benchmarks for comparisons. Various analytical and numerical results are provided which demonstrate a superior performance for source and channel optimized rate and power adaptive scheme. It is also observed that from a distortion outage perspective, the fixed rate adaptive power scheme substantially outperforms an adaptive rate fixed power scheme for delay-limited transmission of quasi-stationary sources over wireless block fading channels. The effect of the characteristics of the quasi-stationary source on performance, and the implication of the results for transmission of stationary sources are also investigated.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6427623]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1562</startPage>
			<endPage>1572</endPage>
			<fileSize>398</fileSize>
			<authors><![CDATA[Joda, Roghayeh;Lahouti, Farshad;]]></authors>
		</item>
		<item>
			<title><![CDATA[Multilayer Codes for Broadcasting over Quasi-Static Fading MIMO Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466336]]></link>
			<description><![CDATA[A number of recent source coding techniques compress the source signal into multiple layers such that a destination is able to reconstruct the original signal (with some distortion) even if it has not received all the layers. Implementation of such source coding techniques in wireless networks requires the application of coding mechanisms (such as multilayer coding) which allow unequal error protection for different layers of the transmitted data. In this paper, we study the performance of multilayer coding for quasi-static fading channels where the source and the destination are equipped with multiple antennas and the Channel-State-Information (CSI) is only known at the destination. We limit the study to the scenarios where the destination is only able to perform successive-decoding (joint-decoding is not possible) and the objective is to find the design of a multilayer code which maximizes the average data rate received at the destination. To this end, we first propose a design rule for constructing a proper multilayer code for Multiple-Input-Multiple-Output (MIMO) networks. Furthermore, the paper presents a procedure which uses the proposed design rule to determine the parameters of the multilayer code. The performance of the designed multilayer coding scheme is then studied for different network setups.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466336]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1573</startPage>
			<endPage>1583</endPage>
			<fileSize>598</fileSize>
			<authors><![CDATA[Pourahmadi, Vahid;Motahari, Abolfazl S.;Khandani, Amir K.;]]></authors>
		</item>
		<item>
			<title><![CDATA[DAC Spectrum of Binary Sources with Equally-Likely Symbols]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451078]]></link>
			<description><![CDATA[Though distributed arithmetic coding (DAC) is an effective implementation of Slepian-Wolf coding, its performance, which is closely linked with its decoding complexity, has not received a thorough analysis. With binary sources with equally-likely symbols as the research object, this paper develops the DAC spectrum and makes use of it as a tool to answer the complexity problem of the ideal DAC decoder. Based on an in-depth analysis on DAC decoding process, we define the DAC spectrum and propose to find it by a recursive formulation. Firstly, the initial DAC spectrum is constrained by a functional equation and the Fourier transform is utilized to obtain its general explicit form. Secondly, an equation is given through which stage-(i+1) DAC spectrum can be deduced from stage-i DAC spectrum. A numerical method is also proposed for calculating DAC spectrum, whose convergency is proved. To measure the complexity of the ideal DAC decoder, we define the expansion factor and relate it to DAC spectrum. It is proved that if binary symbols 0 and 1 are mapped onto partially overlapped intervals [0, q) and [1-q, 1) respectively, the expansion factor will converge to 2q, i.e., the complexity of the ideal rate-&#x03b1; DAC decoder is approximately O(2^{n(1-&#x03b1;)}).]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6451078]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1584</startPage>
			<endPage>1594</endPage>
			<fileSize>825</fileSize>
			<authors><![CDATA[Fang, Yong;]]></authors>
		</item>
		<item>
			<title><![CDATA[Design and Analysis of Deterministic Distributed Beamforming Algorithms in the Presence of Noise]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461034]]></link>
			<description><![CDATA[This paper presents a new deterministic closed-loop phase-alignment algorithm based on quantized feedback from the receiver for distributed beamforming. In contrast with previously proposed methods, which entailed repeated transmissions from all the nodes in the network, this new algorithm requires each node to transmit only once during the synchronization cycle. This drastically reduces the amount of power consumed to achieve phase alignment, yet the new algorithm converges at least as fast as all other existing schemes. In contrast with previous analyses of distributed beamforming based on random phase updates, where noise had been disregarded, here it is explicitly included in the models and shown to have a considerable effect that cannot be ignored. With and without noise, analytical expressions that characterize the performance of the new algorithm are provided, with emphasis on various limiting regimes of interest.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461034]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1595</startPage>
			<endPage>1607</endPage>
			<fileSize>694</fileSize>
			<authors><![CDATA[Thibault, I.;Faridi, A.;Corazza, G.E.;Coralli, A.Vanelli;Lozano, A.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Accurate Sampling Timing Acquisition for Baseband OFDM Power-Line Communication in Non-Gaussian Noise]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466340]]></link>
			<description><![CDATA[In this paper, a novel technique is proposed to address the joint sampling timing acquisition for baseband and broadband power-line communication (BB-PLC) systems using Orthogonal-Frequency-Division-Multiplexing (OFDM), including the sampling phase offset (SPO) and the sampling clock offset (SCO). Under pairwise correlation and joint Gaussian assumption of received signals in frequency domain, an approximated form of the log-likelihood function is derived. Instead of a high complexity two-dimension grid-search on the likelihood function, a five-step method is employed for accurate estimations. Several variants are presented in the same framework with different complexities. Unlike conventional pilot-assisted schemes using the extra phase rotations within one OFDM block, the proposed technique turns to the phase rotations between adjacent OFDM blocks. Analytical expressions of the variances and biases are derived. Extensive simulation results indicate significant performance improvements over conventional schemes. Additionally, effects of several noise models including non-Gaussianity, cyclo-stationarity, and temporal correlation are analyzed and simulated. Robustness of the proposed technique against violation of the joint Gaussian assumption is also verified by simulations.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6466340]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1608</startPage>
			<endPage>1620</endPage>
			<fileSize>910</fileSize>
			<authors><![CDATA[Chen, Chen;Chen, Yun;Ding, Na;Wang, Yizhi;Lin, Jia-Chin;Zeng, Xiaoyang;Huang, Defeng David;]]></authors>
		</item>
		<item>
			<title><![CDATA[Feedback Power Control with Bit Error Outage Probability QoS Measure on the Rayleigh Fading Channel]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461029]]></link>
			<description><![CDATA[We propose to use the probability of instantaneous bit error outage (IBEO) as a new performance measure in the design of an actual feedback power control system. It is defined as the probability that the instantaneous bit error probability (IBEP) exceeds an IBEP threshold. We propose the IBEO-based power control law where the transmitted power is adjusted according to the variations of the channel such that the IBEO probability is kept within some quality of service (QoS)-specified threshold. It ensures that in the long term, no more than a certain fraction of received bits would have IBEP exceeding some IBEP threshold. Therefore, the instantaneous QoS is guaranteed. Based on a practical system model with channel estimation and prediction, we develop the traditional average bit error probability (ABEP)-based power control law and the new IBEO-based power control law. For both laws, we derive explicit ABEP and IBEO probability results. The IBEO-based law shows a remarkable gain over the ABEP-based law in terms of IBEO probability, and sacrifices only a little in the ABEP performance.]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6461029]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1621</startPage>
			<endPage>1631</endPage>
			<fileSize>295</fileSize>
			<authors><![CDATA[Wang, Peijie;Kam, Pooi-Yuen;]]></authors>
		</item>
		<item>
			<title><![CDATA[Call for Papers]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514803]]></link>
			<description><![CDATA[ ]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514803]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>1632</startPage>
			<endPage>1632</endPage>
			<fileSize>33</fileSize>
			<authors><![CDATA[]]></authors>
		</item>
		<item>
			<title><![CDATA[Staff List]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514804]]></link>
			<description><![CDATA[ ]]></description>
			<pubDate><![CDATA[April  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6514804]]></guid>
			<volume>61</volume>
			<issue>4</issue>
			<startPage>c3</startPage>
			<endPage>c3</endPage>
			<fileSize>45</fileSize>
			<authors><![CDATA[]]></authors>
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