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		<title><![CDATA[ Wireless Communications, IEEE Transactions on - new TOC ]]></title>
		<link>http://ieeexplore.ieee.org</link>
		<description>TOC Alert for Publication# 7693 </description>
		<year>2013</year>
		<month>June     </month>
		<day>18</day>
		<item>
			<title><![CDATA[Table of contents]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6521482]]></link>
			<description><![CDATA[Presents the cover/table of contents for this issue of the periodical.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6521482]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>c1</startPage>
			<endPage>c4</endPage>
			<fileSize>112</fileSize>
			<authors><![CDATA[]]></authors>
		</item>
		<item>
			<title><![CDATA[Staff list]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6521483]]></link>
			<description><![CDATA[Provides a listing of current staff, committee members and society officers.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6521483]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>c2</startPage>
			<endPage>c2</endPage>
			<fileSize>61</fileSize>
			<authors><![CDATA[]]></authors>
		</item>
		<item>
			<title><![CDATA[Bilayer Protograph Codes for Half-Duplex Relay Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497022]]></link>
			<description><![CDATA[Despite encouraging advances in the design of relay codes, several important challenges remain. Many of the existing LDPC relay codes are tightly optimized for fixed channel conditions and not easily adapted without extensive re-optimization of the code. Some have high encoding complexity and some need long block lengths to approach capacity. This paper presents a high-performance protograph-based LDPC coding scheme for the half-duplex relay channel that addresses simultaneously several important issues: structured coding that permits easy design, low encoding complexity, embedded structure for convenient adaptation to various channel conditions, and performance close to capacity with a reasonable block length. The application of the coding structure to multi-relay networks is demonstrated. Finally, a simple new methodology for evaluating the end-to-end error performance of relay coding systems is developed and used to highlight the performance of the proposed codes.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497022]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>1969</startPage>
			<endPage>1977</endPage>
			<fileSize>403</fileSize>
			<authors><![CDATA[Van Nguyen, Thuy;Nosratinia, Aria;Divsalar, Dariush;]]></authors>
		</item>
		<item>
			<title><![CDATA[Profit Maximization in Femtocell Service with Contract Design]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493534]]></link>
			<description><![CDATA[Most service providers offer an unlimited data service plan under a flat, fixed-rate contract to meet the huge demand. However, because service quality and user experience can vary dramatically in wireless communications, such a contract design is unable to provide equal service quality for all users, which greatly limits the profit potential of service providers. As a result, mobile industries look to femtocell technology to improve service quality and increase profit by attracting customers. Meanwhile, differentiated contracts for different types of users also show great potential for profit increase. In this paper, we investigate unlimited data service plans in terms of enhancements from both femtocell systems and differentiated contracts. The incentive compatibility (IC) issue in differentiated contract design is considered under the overlay macrocell-femtocell system in both split-spectrum and shared-spectrum models. The profits under optimal differentiated contracts, with and without the IC condition are compared to traditional flat fee contracts, and numerical results show that optimal differentiated contracts indeed generate more profits and serve more users.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493534]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>1978</startPage>
			<endPage>1988</endPage>
			<fileSize>377</fileSize>
			<authors><![CDATA[Wang, Chih-Yu;Wei, Hung-Yu;]]></authors>
		</item>
		<item>
			<title><![CDATA[MIMO Broadcasting for Simultaneous Wireless Information and Power Transfer]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489506]]></link>
			<description><![CDATA[Wireless power transfer (WPT) is a promising new solution to provide convenient and perpetual energy supplies to wireless networks. In practice, WPT is implementable by various technologies such as inductive coupling, magnetic resonate coupling, and electromagnetic (EM) radiation, for short-/mid-/long-range applications, respectively. In this paper, we consider the EM or radio signal enabled WPT in particular. Since radio signals can carry energy as well as information at the same time, a unified study on simultaneous wireless information and power transfer (SWIPT) is pursued. Specifically, this paper studies a multiple-input multiple-output (MIMO) wireless broadcast system consisting of three nodes, where one receiver harvests energy and another receiver decodes information separately from the signals sent by a common transmitter, and all the transmitter and receivers may be equipped with multiple antennas. Two scenarios are examined, in which the information receiver and energy receiver are separated and see different MIMO channels from the transmitter, or co-located and see the identical MIMO channel from the transmitter. For the case of separated receivers, we derive the optimal transmission strategy to achieve different tradeoffs for maximal information rate versus energy transfer, which are characterized by the boundary of a so-called rate-energy (R-E) region. For the case of co-located receivers, we show an outer bound for the achievable R-E region due to the potential limitation that practical energy harvesting receivers are not yet able to decode information directly. Under this constraint, we investigate two practical designs for the co-located receiver case, namely time switching and power splitting, and characterize their achievable R-E regions in comparison to the outer bound.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489506]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>1989</startPage>
			<endPage>2001</endPage>
			<fileSize>529</fileSize>
			<authors><![CDATA[Zhang, Rui;Ho, Chin Keong;]]></authors>
		</item>
		<item>
			<title><![CDATA[Optimal Rate Allocation for Distributed Source Coding over Gaussian Multiple Access Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489504]]></link>
			<description><![CDATA[We study the problem of joint optimization of Slepian-Wolf (SW) source coding and transmission rates over a Gaussian multiple access channel with the considerations of circuit power consumption and average transmit power constraint. The goal is to maximize the sample rate at the source nodes. We first derive a criterion to determine the optimality of different multiple access schemes such that the highest sample rate can be achieved at the source nodes when SW coding is used. Based on the derived optimality criterion, we propose a rate allocation procedure to determine the jointly optimal SW coding and transmission rates corresponding to orthogonal code division multiple access (CDMA), frequency division multiple access (FDMA), time division multiple access (TDMA) and superposition coding with successive interference cancellation (SCSIC) schemes. Several demonstrative numerical examples are provided to show the performance gain of the proposed joint rate allocation scheme.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489504]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2002</startPage>
			<endPage>2013</endPage>
			<fileSize>948</fileSize>
			<authors><![CDATA[Wang, Tianqi;Seyedi, Alireza;Vosoughi, Azadeh;Heinzelman, Wendi;]]></authors>
		</item>
		<item>
			<title><![CDATA[Novel Adaptive Nonlinear Receivers for UWB Multiple Access Communications]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485025]]></link>
			<description><![CDATA[Ultra-wide bandwidth communication systems are known to suffer from non-Gaussian interference. In general, wireless ad-hoc networks, due to the lack of perfect power control and the random placement of nodes, are very likely to experience non-Gaussian multiple access interference. In systems with additive non-Gaussian noise, non-Gaussian signal detection and nonlinear signal processing can play important roles, especially in suppressing the multiple access interference. Practical ultra-wide bandwidth receiver designs based on the &#x03b1;-stable non-Gaussian additive impairment model are proposed and evaluated. It is demonstrated that the &#x03b1;-stable model together with a fractile based parameter estimation technique constitute a robust technique for adaptive receiver designs. The proposed receivers based on the &#x03b1;-stable model suppress multiple access interference, adapt to the noise and the interference in the environment, and are robust to estimation errors in the receiver parameters. The proposed receivers provide much better bit error rates than linear detectors and previously known nonlinear detectors.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485025]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2014</startPage>
			<endPage>2023</endPage>
			<fileSize>424</fileSize>
			<authors><![CDATA[Niranjayan, S.;Beaulieu, Norman C.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Privacy-Preserving Distributed Profile Matching in Proximity-Based Mobile Social Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493536]]></link>
			<description><![CDATA[Making new connections according to personal preferences is a crucial service in mobile social networking, where an initiating user can find matching users within physical proximity of him/her. In existing systems for such services, usually all the users directly publish their complete profiles for others to search. However, in many applications, the users' personal profiles may contain sensitive information that they do not want to make public. In this paper, we propose FindU, a set of privacy-preserving profile matching schemes for proximity-based mobile social networks. In FindU, an initiating user can find from a group of users the one whose profile best matches with his/her; to limit the risk of privacy exposure, only necessary and minimal information about the private attributes of the participating users is exchanged. Two increasing levels of user privacy are defined, with decreasing amounts of revealed profile information. Leveraging secure multi-party computation (SMC) techniques, we propose novel protocols that realize each of the user privacy levels, which can also be personalized by the users. We provide formal security proofs and performance evaluation on our schemes, and show their advantages in both security and efficiency over state-of-the-art schemes.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493536]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2024</startPage>
			<endPage>2033</endPage>
			<fileSize>2653</fileSize>
			<authors><![CDATA[Li, Ming;Yu, Shucheng;Cao, Ning;Lou, Wenjing;]]></authors>
		</item>
		<item>
			<title><![CDATA[Relay Selection Strategies for Single-Carrier Frequency-Domain Equalization Multi-Relay Cooperative Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489505]]></link>
			<description><![CDATA[In this paper, we investigate several relay selection strategies for cooperative Single-Carrier Frequency-Domain Equalization (SC-FDE) with the amplify-and-forward protocol. We consider both maximum likelihood (ML)-SC-FDE and minimum mean square error (MMSE)-SC-FDE receivers. We provide a novel pairwise error probability (PEP)-based selection criterion (SHARM) for frequency selective channels. We further present several selection strategies for cooperative (C) MMSE-SC-FDE receivers, which are motivated by minimizing the instantaneous error rate. These are, norm-based relay selection (NBRS), instantaneous mutual information-based relay selection (CBRS), singular value based relay selection (SVRS), and equalizer output signal quality-based relay selection (EQRS) strategies. We further propose a novel relay selection strategy, selective-to-flat fading relay selection (SFRS), in which from the effective frequency selective source-relay-destination channel link associated with the selected relay, only the channel tab with highest power is passed to the destination terminal. Additionally, to tackle the multiple relay selection problem considering generic mobile scenarios with moderately fast fading channels, in order to select the near best relay subset within the minimum processing time, we apply estimation of distribution algorithm (EDA) and formulate a modified EDA for the relay selection problem. Our results show promising performance of EDA with comparable computational complexity.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489505]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2034</startPage>
			<endPage>2045</endPage>
			<fileSize>597</fileSize>
			<authors><![CDATA[Eghbali, Homa;Muhaidat, Sami;Hejazi, Seyed Amin;Ding, Yanwu;]]></authors>
		</item>
		<item>
			<title><![CDATA[Resource Allocation for QoS Support in Wireless Mesh Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6463489]]></link>
			<description><![CDATA[Many next generation applications (such as video flows) are likely to have associated minimum data rate requirements in order to ensure satisfactory quality as perceived by end-users. In this paper, we develop a framework to address the problem of maximizing the aggregate utility of traffic flows in a multi-hop wireless network, with constraints imposed both due to self-interference and minimum rate requirements. The parameters that are tuned in order to maximize the utility are (i) transmission powers of individual nodes and (ii) the channels assigned to the different communication links. Our framework is based on using a cross-decomposition technique that takes both inter-flow interference and self-interference into account. The output of our framework is a schedule that dictates what links are to be activated in each slot and the parameters associated with each of those links. If the minimum rate constraint cannot be satisfied for all of the flows, the framework intelligently rejects a sub-set of the flows and recomputes a schedule for the remaining flows. We also design an admission control module that determines if new flows can be admitted without violating the rate requirements of the existing flows in the network. We provide numerical results to demonstrate the efficacy of our framework.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6463489]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2046</startPage>
			<endPage>2054</endPage>
			<fileSize>614</fileSize>
			<authors><![CDATA[Kim, Tae-Suk;Yang, Yong;Hou, Jennifer C.;Krishnamurthy, Srikanth V.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Distributed Multiuser Sequential Channel Sensing Schemes in Multichannel Cognitive Radio Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493528]]></link>
			<description><![CDATA[Effective spectrum sensing strategies enable cognitive radios (CRs) to identify and opportunistically transmit on under-utilized spectral resources. In this paper, sequential channel sensing problems for single and multiple secondary users (SUs) networks are effectively modeled through finite state Markovian processes. More specifically, a model for single user case is introduced and its performance is validated through analytical analysis. Then, in order to address multiple SUs case, this model is extended to include the modified p-persistent access (MPPA) protocol. Since the scheme utilized experiences a high level of collision among the SUs, to mitigate the problem appropriately, p-persistent random access (PPRA) protocol is considered, which offers higher average throughput for SUs by statistically distributing their loads among all channels. The structure and performance of the proposed schemes are discussed in detail, and a set of illustrative numerical results is presented to validate and compare the performance of the proposed sense-access strategies.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493528]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2055</startPage>
			<endPage>2067</endPage>
			<fileSize>450</fileSize>
			<authors><![CDATA[Shokri-Ghadikolaei, Hossein;Sheikholeslami, Fatemeh;Nasiri-Kenari, Masoumeh;]]></authors>
		</item>
		<item>
			<title><![CDATA[Design and Analysis of an Acknowledgment-Aware Asynchronous MPR MAC Protocol for Distributed WLANs]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493529]]></link>
			<description><![CDATA[Multi-packet reception (MPR) promises significant throughput gains in wireless local area networks (WLANs) by allowing nodes to transmit even in the presence of ongoing transmissions in the medium. However, the medium access control (MAC) layer must now be redesigned to facilitate &#x2014; rather than discourage &#x2014; these overlapping transmissions. We investigate asynchronous MPR MAC protocols, which successfully accomplish this by controlling the node behavior based on the number of ongoing transmissions in the channel. The protocols use the backoff timer mechanism of the distributed coordination function, which makes them practically appealing. We first highlight a unique problem of acknowledgment delays, which arises in asynchronous MPR, and investigate a solution that modifies the medium access rules to reduce these delays and increase system throughput in the single receiver scenario. We develop a general renewal-theoretic fixed-point analysis that leads to expressions for the saturation throughput, packet dropping probability, and average head-of-line packet delay. We also model and analyze the practical scenario in which nodes may incorrectly estimate the number of ongoing transmissions.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493529]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2068</startPage>
			<endPage>2079</endPage>
			<fileSize>1275</fileSize>
			<authors><![CDATA[Mukhopadhyay, Arpan;Mehta, Neelesh B.;Srinivasan, Vikram;]]></authors>
		</item>
		<item>
			<title><![CDATA[Random Beamforming with Heterogeneous Users and Selective Feedback: Individual Sum Rate and Individual Scaling Laws]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493530]]></link>
			<description><![CDATA[This paper investigates three open problems in random beamforming based communication systems: the scheduling policy with heterogeneous users, the closed form sum rate, and the randomness of multiuser diversity with selective feedback. By employing the cumulative distribution function based scheduling policy, we guarantee fairness among users as well as obtain multiuser diversity gain in the heterogeneous scenario. Under this scheduling framework, the individual sum rate, namely the average rate for a given user multiplied by the number of users, is of interest and analyzed under different feedback schemes. Firstly, under the full feedback scheme, we derive the closed form individual sum rate by employing a decomposition of the probability density function of the selected user's signal-to-interference-plus-noise ratio. This technique is employed to further obtain a closed form rate approximation with selective feedback in the spatial dimension. The analysis is also extended to random beamforming in a wideband OFDMA system with additional selective feedback in the spectral dimension wherein only the best beams for the best-L resource blocks are fed back. We utilize extreme value theory to examine the randomness of multiuser diversity incurred by selective feedback. Finally, by leveraging the tail equivalence method, the multiplicative effect of selective feedback and random observations is observed to establish the individual rate scaling.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493530]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2080</startPage>
			<endPage>2090</endPage>
			<fileSize>1060</fileSize>
			<authors><![CDATA[Huang, Yichao;Rao, Bhaskar D.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Performance Improvement of Switched-Based Interference Mitigation for Channel Assignment in Over-Loaded Small-Cell Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497015]]></link>
			<description><![CDATA[This paper proposes adequate methods to improve the interference mitigation capability of a recently investigated switched-based interference reduction scheme for single downlink channel assignment in over-loaded small-cell networks. The model assumes that the available orthogonal channels for small cells are distributed among access points in close vicinity, where each access point knows its allocated channels a priori. Each cell has a single antenna, employs the open access strategy, and can reuse its allocated channels simultaneously, while scheduling concurrent service requests. Moreover, the access points can not coordinate their transmissions, and can receive limited feedback from active users. The paper presents low-complexity schemes to identify a suitable channel to serve the scheduled user by maintaining the interference power level within a tolerable range. They attempt to either complement the switched-based scheme by minimum interference channel selection or adopt different interference thresholds on available channels, while reducing the channel examination load. The optimal thresholds for interference mitigation at the desired receive station are quantified for various performance criteria. The performance and processing load of the proposed schemes are obtained analytically, and then compared to those of the single-threshold scheme via numerical and simulation results.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497015]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2091</startPage>
			<endPage>2103</endPage>
			<fileSize>466</fileSize>
			<authors><![CDATA[Gaaloul, Fakhreddine;Radaydeh, Redha M.;Alouini, Mohamed-Slim;]]></authors>
		</item>
		<item>
			<title><![CDATA[Optimal Two-Dimensional Lattices for Precoding of Linear Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6515994]]></link>
			<description><![CDATA[Consider the communication system model y = HFx + n, where H and F are the channel and precoder matrices, x is a vector of data symbols drawn from some lattice-type constellation, such as M-QAM, n is an additive white Gaussian noise vector and y is the received vector. It is assumed that both the transmitter and the receiver have perfect knowledge of the channel matrix H and that the transmitted signal Fx is subject to an average energy constraint. The columns of the matrix HF can be viewed as the basis vectors that span a lattice, and we are interested in the precoder F that maximizes the minimum distance of this lattice. This particular problem remains open within the theory of lattices and the communication theory. This paper provides the complete solution for any non-singular Mx 2 channel matrix H. For real-valued matrices and vectors, the solution is that HF spans the hexagonal lattice. For complex-valued matrices and vectors, the solution is that HF, when viewed in four-dimensional real-valued space, spans the Schlafli lattice D_4.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6515994]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2104</startPage>
			<endPage>2113</endPage>
			<fileSize>356</fileSize>
			<authors><![CDATA[Kapetanovic, Dzevdan;Cheng, Hei Victor;Mow, Wai Ho;Rusek, Fredrik;]]></authors>
		</item>
		<item>
			<title><![CDATA[Random Access Compressed Sensing over Fading and Noisy Communication Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489510]]></link>
			<description><![CDATA[Random Access Compressed Sensing (RACS) is an efficient method for data gathering from a network of distributed sensors with limited resources. RACS relies on integrating random sensing with the communication architecture, and achieves overall efficiency in terms of the energy per bit of information successfully delivered. To address realistic deployment conditions, we consider data gathering over a fading and noisy communication channel. We provide a framework for system design under various fading conditions, and quantify the bandwidth and energy requirements of RACS in fading. We show that for most practical values of the signal to noise ratio, energy utilization is higher in a fading channel than it is in a non-fading channel, while the minimum required bandwidth is lower. Finally, we demonstrate the savings in the overall energy and the bandwidth requirements of RACS compared to a conventional TDMA scheme. We show that considerable gains in energy -on the order of 10 dB- are achievable, as well as a reduction in the required bandwidth, e.g., 2.5-fold decrease in the bandwidth for a network of 4000 nodes.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489510]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2114</startPage>
			<endPage>2125</endPage>
			<fileSize>451</fileSize>
			<authors><![CDATA[Fazel, Fatemeh;Fazel, Maryam;Stojanovic, Milica;]]></authors>
		</item>
		<item>
			<title><![CDATA[Dynamic Base Station Switching-On/Off Strategies for Green Cellular Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489498]]></link>
			<description><![CDATA[In this paper, we investigate dynamic base station (BS) switching to reduce energy consumption in wireless cellular networks. Specifically, we formulate a general energy minimization problem pertaining to BS switching that is known to be a difficult combinatorial problem and requires high computational complexity as well as large signaling overhead. We propose a practically implementable switching-on/off based energy saving (SWES) algorithm that can be operated in a distributed manner with low computational complexity. A key design principle of the proposed algorithm is to turn off a BS one by one that will minimally affect the network by using a newly introduced notion of network-impact, which takes into account the additional load increments brought to its neighboring BSs. In order to further reduce the signaling and implementation overhead over the air and backhaul, we propose three other heuristic versions of SWES that use the approximate values of network-impact as their decision metrics. We describe how the proposed algorithms can be implemented in practice at the protocol-level and also estimate the amount of energy savings through a first-order analysis in a simple setting. Extensive simulations demonstrate that the SWES algorithms can significantly reduce the total energy consumption, e.g., we estimate up to 50-80% potential savings based on a real traffic profile from a metropolitan urban area.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489498]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2126</startPage>
			<endPage>2136</endPage>
			<fileSize>472</fileSize>
			<authors><![CDATA[Oh, Eunsung;Son, Kyuho;Krishnamachari, Bhaskar;]]></authors>
		</item>
		<item>
			<title><![CDATA[A Peak Power Efficient Cooperative Diversity using Star-QAM with Coherent/Noncoherent Detection]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489499]]></link>
			<description><![CDATA[In this paper, we propose a new simple relaying strategy based on bit-interleaved convolutionally coded star-quadrature amplitude modulation (QAM) along with coherent/noncoherent detection. Star-QAM is composed of multiple concentric circles of phase-shift keying (PSK). Exploiting this property, a hard limiter is used to enhance power amplifier (PA) efficiency at the relay. Moreover, we show that the proposed approach retains differential detectability, which results in a significant reduction of receiver complexity with robustness against phase ambiguity. By analyzing our proposed cooperation with coherent/noncoherent detection in terms of asymptotic pairwise error probability (PEP), we show that the full diversity order can be achieved on the condition that the minimum free distance of the convolutional codes is larger than the predetermined value specified by the number of available relays. Furthermore, the effectiveness of the proposed scheme in terms of PA efficiency is confirmed by comparing the statistical distributions of the corresponding instantaneous signal powers. All the theoretical results agree with those obtained by computer simulations.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489499]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2137</startPage>
			<endPage>2147</endPage>
			<fileSize>6444</fileSize>
			<authors><![CDATA[Ishibashi, Koji;Shin, Won-Yong;Ochiai, Hideki;Tarokh, Vahid;]]></authors>
		</item>
		<item>
			<title><![CDATA[A Stackelberg Model for Opportunistic Sensing in Cognitive Radio Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489500]]></link>
			<description><![CDATA[We consider a non-cooperative Dynamic Spectrum Access (DSA) game where Secondary Users (SUs) access opportunistically the spectrum licensed for Primary Users (PUs). As SUs spend energy for sensing licensed channels, they may choose to be inactive during a given time slot in order to save energy. Then, there exists a tradeoff between large packet delay, partially due to collisions between SUs, and high-energy consumption spent for sensing the occupation of licensed channels. To overcome this problem, we take into account packet delay and energy consumption into our framework. Due to the partial spectrum sensing, we use a Partial Observable Stochastic Game (POSG) formalism, and we analyze the existence and some properties of the Nash equilibrium using a Linear Program (LP). We identify a paradox: when licensed channels are more occupied by PUs, this may improve the spectrum utilization by SUs. Based on this observation, we propose a Stackelberg formulation of our problem where the network manager may increase the occupation of licensed channels in order to improve the SUs' average throughput. We prove the existence of a Stackelberg equilibrium and we provide some simulations that validate our theoretical findings.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489500]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2148</startPage>
			<endPage>2159</endPage>
			<fileSize>699</fileSize>
			<authors><![CDATA[Habachi, Oussama;El-azouzi, Rachid;Hayel, Yezekael;]]></authors>
		</item>
		<item>
			<title><![CDATA[Lattice Reduction-Based MIMO Iterative Receiver Using Randomized Sampling]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489509]]></link>
			<description><![CDATA[For iterative detection and decoding (IDD) in multiple-input multiple-output (MIMO) systems, although the maximum a posteriori probability (MAP) detector is desirable in terms of performance, it is difficult to be employed due to its prohibitively high complexity as an exhaustive search is used. In this paper, a lattice reduction (LR)-based MIMO detection method is studied to achieve near MAP performance with reasonably low complexity for IDD. The a priori information (API), which is available from a soft-input soft-output (SISO) decoder, is taken into account to generate a list with a randomized successive interference cancellation (SIC) method. More specifically, a joint Gaussian distribution is used to convert the API into the LR domain and a modified sampling distribution, which was originally adopted for near optimal LR-based detection in non-IDD MIMO systems, is derived for random sampling to build a list of candidate vectors of high a posteriori probability (APP) with low complexity. It is shown that the IDD receiver with the proposed method outperforms those with the conventional LR-based methods, where no API is taken into account to build a list. Furthermore, the trade-off between performance and complexity is exploited with varying list length.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489509]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2160</startPage>
			<endPage>2170</endPage>
			<fileSize>413</fileSize>
			<authors><![CDATA[Bai, Lin;Choi, Jinho;]]></authors>
		</item>
		<item>
			<title><![CDATA[Frequency-Selective Joint Tx/Rx I/Q Imbalance Estimation Using Golay Complementary Sequences]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497016]]></link>
			<description><![CDATA[The increasing use of smaller technologies in the manufacture of analog front&#x2014;ends (AFEs) for communication systems has increased the impact their non&#x2014;ideal components produce. This results in a significant degradation of the system performance that must be identified and addressed. In particular, the I/Q imbalance is commonly estimated and compensated via digital signal processing techniques using training sequences. In order to preclude the rise of other non&#x2014;idealities, such as the non&#x2014;linearity of the power amplifier (PA), these training sequences should be chosen to have a low peak&#x2014;to&#x2014;average power ratio (PAPR). In addition, it is desirable that these techniques have reduced computational complexity for minimizing estimation times and area resources. This paper presents a novel I/Q imbalance estimation algorithm that is computationally simple, it only requires adders and shifters, while exhibiting a PAPR &#x02264; 2. It can include the transmitter and receiver I/Q imbalances as well as the multipath phenomena. It is based on a newly used property of Golay complementary sequences (GCS). The statistical efficiency and low complexity of the proposed algorithm are proved, while its flexibility is illustrated under several extreme test cases.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497016]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2171</startPage>
			<endPage>2179</endPage>
			<fileSize>528</fileSize>
			<authors><![CDATA[Rodriguez-Avila, R.;Nunez-Vega, G.;Parra-Michel, R.;Mendez-Vazquez, A.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Opportunistic Interference Alignment for MIMO Interfering Multiple-Access Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493532]]></link>
			<description><![CDATA[We consider the K-cell multiple-input multiple-output (MIMO) interfering multiple-access channel (IMAC) with time-invariant channel coefficients, where each cell consists of a base station (BS) with M antennas and N users having L antennas each. In this paper, we propose two opportunistic interference alignment (OIA) techniques utilizing multiple transmit antennas at each user: antenna selection-based OIA and singular value decomposition (SVD)-based OIA. Their performance is analyzed in terms of user scaling law required to achieve KS degrees-of-freedom (DoF), where S(&#x02264; M) denotes the number of simultaneously transmitting users per cell. We assume that each selected user transmits a single data stream at each time-slot. It is shown that the antenna selection-based OIA does not fundamentally change the user scaling condition if L is fixed, compared with the single-input multiple-output (SIMO) IMAC case, which is given by SNR^{(K-1)S}, where SNR denotes the signal-to-noise ratio. In addition, we show that the SVD-based OIA can greatly reduce the user scaling condition to SNR^{(K-1)S-L+1} through optimizing a weight vector at each user. Simulation results validate the derived scaling laws of the proposed OIA techniques. The sum-rate performance of the proposed OIA techniques is compared with the conventional techniques in MIMO IMAC channels and it is shown that the proposed OIA techniques outperform the conventional techniques.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493532]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2180</startPage>
			<endPage>2192</endPage>
			<fileSize>706</fileSize>
			<authors><![CDATA[Yang, Hyun Jong;Shin, Won-Yong;Jung, Bang Chul;Paulraj, Arogyaswami;]]></authors>
		</item>
		<item>
			<title><![CDATA[Relay Selection and Resource Allocation for Multi-User Cooperative OFDMA Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493531]]></link>
			<description><![CDATA[The resource allocation problem is investigated for relay-based multi-user cooperative Orthogonal Frequency Division Multiple Access (OFDMA) uplink system, considering heterogeneous services. A quality of service (QoS) aware optimal relay selection, power allocation and subcarrier assignment scheme under a total power constraint is proposed. The relay selection, power allocation and subcarrier assignment problem is formulated as a joint optimization problem with the objective of maximizing the system throughput, which is solved by means of a two level dual decomposition and subgradient method. To further reduce the computational cost, two low-complexity suboptimal schemes are also proposed. The performance of the proposed schemes is demonstrated through computer simulations based on LTE-A network. Numerical results show that the proposed schemes support heterogeneous services while guaranteeing each user's QoS requirements with slight total system throughput degradation.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493531]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2193</startPage>
			<endPage>2205</endPage>
			<fileSize>817</fileSize>
			<authors><![CDATA[Alam, Md Shamsul;Mark, Jon W.;Shen, Xuemin Sherman;]]></authors>
		</item>
		<item>
			<title><![CDATA[QoS-Aware Transmission Policies for OFDM Bidirectional Decode-and-Forward Relaying]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485031]]></link>
			<description><![CDATA[Two-way relaying can considerably improve spectral efficiency in relay-assisted bidirectional communications. However, the benefits and flexible structure of orthogonal frequency division multiplexing (OFDM)-based two-way relay systems is much less exploited. Moreover, most of existing works have not considered quality-of-service (QoS) provisioning for two-way relaying. In this paper, we consider the OFDM-based bidirectional transmission where a pair of users exchange information via the assistance of a decode-and-forward (DF) relay. Each user can communicate with the other via three transmission modes: direct transmission, one-way relaying, and two-way relaying. We jointly optimize the transmission policies, including power allocation, transmission mode selection, and subcarrier assignment in order to maximize the weighted sum rates of the two users with diverse QoS guarantees. This is formulated as a mixed integer programming problem. By using the dual method, we efficiently solve the problem in an asymptotically optimal manner. Simulation results show that the proposed resource allocation scheme can substantially improve system performance compared with conventional schemes. A number of interesting insights are also obtained via comprehensive simulations.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485031]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2206</startPage>
			<endPage>2216</endPage>
			<fileSize>635</fileSize>
			<authors><![CDATA[Liu, Yuan;Mo, Jianhua;Tao, Meixia;]]></authors>
		</item>
		<item>
			<title><![CDATA[Robust Performance of Spectrum Sensing in Cognitive Radio Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497011]]></link>
			<description><![CDATA[The successful coexistence of secondary users (SUs) and primary users (PUs) in cognitive radio networks requires SUs to be spectrum aware and know which spectrum bands are occupied by PUs. Such awareness can be achieved in several ways, one of which is spectrum sensing. While existing spectrum sensing methods usually assume known distributions of the received primary signals, such an assumption is often too strong and unrealistic, and leads to unreliable detection performance in practical networks. In this paper, we design robust spectrum sensing algorithms under the distribution uncertainty of primary signals. After formulating the optimal sensing design as a robust optimization problem, we decompose it into a series of analytically tractable semi-definite programs, and propose an iterative algorithm to search the optimal decision threshold while maintaining the desirable false alarm probability during the iterations. Numerical results verify that our robust sensing algorithm improves the worst-case detection probability and reduces the system sensitivity on decision variables.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497011]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2217</startPage>
			<endPage>2227</endPage>
			<fileSize>479</fileSize>
			<authors><![CDATA[Gong, Shimin;Wang, Ping;Huang, Jianwei;]]></authors>
		</item>
		<item>
			<title><![CDATA[Impact of Overhead on Spectral Efficiency of Cooperative Relaying]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497018]]></link>
			<description><![CDATA[It is well known that cooperative relaying has the potential to improve the performance of wireless communication. However, compared with point-to-point communication, cooperative relaying requires much more overhead to implement. In this paper, we quantitatively analyze the overhead in implementing cooperative relaying, in particular, the overhead to acquire essential channel state information, to select the relay(s), and to provide the required coordination. Factoring in the impact of overhead, the spectral efficiency of cooperative relaying schemes is then investigated. A comparison of three cooperative relaying schemes (Timer-Based Best-Select, Distributed Space-Time-Coded, and M-group) is presented. Numerical results are provided to illustrate the impact of overhead on the spectral efficiency. Finally, based on the analysis and simulations, we provide guidelines for determining the appropriate cooperative relaying scheme for specific scenarios.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497018]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2228</startPage>
			<endPage>2239</endPage>
			<fileSize>381</fileSize>
			<authors><![CDATA[Xiao, Yao;Cimini, Leonard J.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Performance Analysis of Macrodiversity MIMO Systems with MMSE and ZF Receivers in Flat Rayleigh Fading]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493526]]></link>
			<description><![CDATA[Consider a multiuser system where an arbitrary number of users communicate with a distributed receive array over independent Rayleigh fading paths. The receive array performs minimum mean squared error (MMSE) or zero forcing (ZF) combining and perfect channel state information is assumed at the receiver. This scenario is well-known and exact analysis is possible when the receive antennas are located in a single array. However, when the antennas are distributed, the individual links all have different average signal to noise ratio (SNRs) and this is a much more challenging problem. In this paper, we provide approximate distributions for the output SNR of a ZF receiver and the output signal to interference plus noise ratio (SINR) of an MMSE receiver. In addition, simple high SNR approximations are provided for the symbol error rate (SER) of both receivers assuming M-PSK or M-QAM modulations. These high SNR results provide array gain and diversity gain information as well as a remarkably simple functional link between performance and the link powers.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493526]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2240</startPage>
			<endPage>2251</endPage>
			<fileSize>732</fileSize>
			<authors><![CDATA[Basnayaka, Dushyantha A.;Smith, Peter J.;Martin, Phillipa A.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Prescient Precoding in Heterogeneous DSA Networks with Both Underlay and Interweave MIMO Cognitive Radios]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489508]]></link>
			<description><![CDATA[This work examines a novel heterogeneous dynamic spectrum access network where the primary users (PUs) coexist with both underlay and interweave cognitive transmitters (UCTs and ICTs); all terminals being potentially equipped with multiple antennas. UCTs are allowed to transmit concurrently with PUs subject to interference constraints, while the ICTs employ spectrum sensing and are permitted to access the shared spectrum only when both PUs and UCTs are absent. We investigate the design of MIMO precoding algorithms for the UCT that increase the detection probability at the ICTs, while simultaneously meeting a desired Quality-of-Service target to the underlay cognitive receivers (UCRs) and constraining interference leaked to PUs. The objective of such a proactive approach, referred to as prescient precoding, is to minimize the probability of interference from ICTs to the UCRs and primary receivers due to imperfect spectrum sensing. We begin with downlink prescient precoding algorithms for multiple single-antenna UCRs and multi-antenna PUs/ICTs. We then present prescient block-diagonalization algorithms for the MIMO underlay downlink where spatial multiplexing is performed for a plurality of multi-antenna UCRs. Numerical experiments demonstrate that prescient precoding by UCTs provides a pronounced performance gain compared to conventional underlay precoding strategies.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489508]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2252</startPage>
			<endPage>2260</endPage>
			<fileSize>573</fileSize>
			<authors><![CDATA[Mukherjee, Amitav;Swindlehurst, A.Lee;]]></authors>
		</item>
		<item>
			<title><![CDATA[Exact Formulations for the Throughput of IEEE 802.11 DCF in Hoyt, Rice, and Nakagami-m Fading Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493527]]></link>
			<description><![CDATA[This paper investigates the throughput performance of IEEE 802.11 Distributed Coordination Function (DCF) at the Medium Access Control (MAC) layer with Hoyt, Rice and Nakagami-m fading environments. The approach considered includes the signal capture model with incoherent addition of interfering signals and uniform attenuation for all terminals (or perfect power control). For the Hoyt and Rice fading channels, the results presented also cover the case of coherent addition of interfering signals. Furthermore, for the Nakagami-m fading channel, the case of unequal average power levels is also studied. For the sake of comparison, results for the carrier sense multiple access with collision avoidance (CSMA/CA) are also presented. The formulations derived here are exact and unprecedented in the literature. Some of these formulations are given in infinite series form whereas several of them are presented in closed-form expressions. For the series-based ones, only a few terms are required in order to achieve high accuracy results.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493527]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2261</startPage>
			<endPage>2271</endPage>
			<fileSize>336</fileSize>
			<authors><![CDATA[Leonardo, Elvio J.;Yacoub, Michel D.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Space Time Coding for Backscatter RFID]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485029]]></link>
			<description><![CDATA[In this work, the use of Space-Time Codes in passive Radio Frequency IDentification (RFID) systems is explored; this is feasible whenever a tag possesses multiple antennas. Information is encoded across the multiple tag antennas and received by an RFID reader, also typically equipped with multiple antennas. The nature of passive RFID induces a unique fading channel known as the dyadic backscatter channel, which differs statistically compared to the canonical Rayleigh fading channel. We introduce a modified dyadic channel for RFID backscatter that adequately captures the space-time coding paradigm. We then propose known orthogonal space-time codes and derive an upper bound on the the pairwise error probability (PEP), leading to estimates of the (asymptotic) diversity order. Interestingly, the diversity order is shown to depend only on the number of tag antennas but not the number of receive antennas; the resultant performance trade-offs is discussed. Lastly, simulation of the symbol error rates for different channel configurations are conducted to validate the analysis.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485029]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2272</startPage>
			<endPage>2280</endPage>
			<fileSize>401</fileSize>
			<authors><![CDATA[Boyer, Colby;Roy, Sumit;]]></authors>
		</item>
		<item>
			<title><![CDATA[Distributed Power Allocation for Coordinated Multipoint Transmissions in Distributed Antenna Systems]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497013]]></link>
			<description><![CDATA[This paper investigates the distributed power allocation problem for coordinated multipoint (CoMP) transmissions in distributed antenna systems (DAS). Traditional duality-based optimization techniques cannot be directly applied to this problem, because the non-strict concavity of the CoMP transmission's achievable rate with respect to the transmission power induces that the local power allocation subproblems have non-unique optimum solutions. We propose a distributed power allocation algorithm to resolve this non-strict concavity difficulty. This algorithm only requires local information exchange among neighboring base stations serving the same user, and is thus flexible with respect to network size and topology. The step-size parameters of this algorithm are determined by only local user access relationship (i.e., the number of users served by each antenna), but do not rely on channel coefficients. Therefore, the convergence speed of this algorithm is quite robust to channel fading. We rigorously prove that this algorithm converges to an optimum solution of the power allocation problem. Simulation results are presented to demonstrate the effectiveness of the proposed power allocation algorithm.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497013]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2281</startPage>
			<endPage>2291</endPage>
			<fileSize>568</fileSize>
			<authors><![CDATA[Zhang, Xiujun;Sun, Yin;Chen, Xiang;Zhou, Shidong;Wang, Jing;Shroff, Ness B.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Interference Pricing for SINR-Based Random Access Game]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485030]]></link>
			<description><![CDATA[In this paper, we study the problem of random access with interference pricing in wireless ad hoc networks using non-cooperative game theory. While most of the previous works in random access games are based on the protocol model, we analyze the game under the more accurate signal-to-interference-plus-noise-ratio (SINR) model. First, under the setting with fixed interference linear pricing, we characterize the existence of the Nash equilibrium (NE) in the random access game. In particular, when the utility functions of all the players satisfy a risk aversion condition, we show that the game is a S-modular game and characterize the convergence of the strategy profile to the NE. Then, under the setting with adaptive interference linear pricing, we propose an iterative algorithm that aims to solve the network utility maximization (NUM) problem. Convergence of the solution to a Karush-Kuhn-Tucker (KKT) point of the NUM problem is studied. It can be shown that the solution obtained under the protocol model may result in starvation for some users due to the inaccurate interference pricing. Simulation results show that our proposed algorithm based on the SINR model achieves a higher average utility than the algorithm based on the protocol model and a carrier sense multiple access (CSMA) scheme implemented in a slotted time system.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485030]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2292</startPage>
			<endPage>2301</endPage>
			<fileSize>344</fileSize>
			<authors><![CDATA[Cheung, Man Hon;Wong, Vincent W.S.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Energy-Efficient Uplink Multi-User MIMO]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497014]]></link>
			<description><![CDATA[This paper addresses optimal energy-efficient design for uplink (UL) MU-MIMO in a single cell environment. The energy efficiency is measured by throughput per Joule, while both RF transmission power and device electronic circuit power are considered. We define the energy efficiency (EE) capacity for UL MU-MIMO and study the power allocation that achieves this capacity. First we assume all users consume a fixed amount of circuit power and show that user antennas should be used only when the corresponding spatial channels are sufficiently good and using them improves the overall network EE. Mobile devices may have improved circuit management capability and turn off circuit operations when some antennas are not used to reduce circuit power consumption. Therefore we further study energy-efficient UL MU-MIMO with improved circuit management and show that some antennas should not be used even when their channel states are good because turning them on consumes too much circuit power. Based on theoretical analysis, we further develop low-complexity yet globally optimal energy-efficient power allocation algorithms that converge to the optimum exponentially. Simulation results are provided to demonstrate the significant gain in network energy efficiency.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497014]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2302</startPage>
			<endPage>2313</endPage>
			<fileSize>409</fileSize>
			<authors><![CDATA[Miao, Guowang;]]></authors>
		</item>
		<item>
			<title><![CDATA[Performance Analysis of OFDM Systems with Selected Mapping in the Presence of Nonlinearity]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497005]]></link>
			<description><![CDATA[In the presence of nonlinearity, we analyze the impact of the selected mapping (SLM) technique on bit-error-rate (BER) performance of orthogonal frequency division multiplexing (OFDM) systems in an additive white Gaussian noise channel. The peak-to-average-ratio (PAR) reduction gain of SLM can be increased by improving the PAR statistics at the cost of complexity in the OFDM transmitter, thereby helping to decrease the required power amplifier (PA) output backoff (OBO). However, since the PAR statistics focus only on the statistical distribution of the highest peak in an OFDM symbol, the statistics cannot be used to quantify BER performance degradation in the presence of nonlinearity such as that caused by a PA or digital-to-analog converter (DAC). We first derive a closed-form expression for the envelope power distribution in an OFDM system with SLM. Then, using this derived envelope power distribution, we investigate the BER performance and the total degradation (TD) of OFDM systems with SLM under the existence of nonlinearity. We discuss peak backoff (PBO) and the clipping ratio, which determine the operating point of the PA and dynamic range of the DAC, respectively. Lastly, we consider the total degradation (TD), which indicates the tradeoff between the OBO and the E_b/N_o penalty due to nonlinearity, and numerically compute the PBO and clipping ratio that minimize the TD. The TD-minimizing PBO and clipping ratio are given as functions of the number of candidate signals in SLM.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497005]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2314</startPage>
			<endPage>2322</endPage>
			<fileSize>590</fileSize>
			<authors><![CDATA[Bae, Kitaek;Shin, Changyong;Powers, Edward J.;]]></authors>
		</item>
		<item>
			<title><![CDATA[The RM^2 Nakagami Fading Channel Simulator]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493524]]></link>
			<description><![CDATA[We propose a new Nakagami phase-envelope fading channel simulator that (i) allows for arbitrary real values of fading parameter, (ii) exactly matches the Nakagami first-order statistics, (iii) and closely matches the second-order statistics classically assigned to Nakagami fading. The proposed simulator is based on a cascade of two existing simulators&#x2014;the random-mixture simulator and the rank-matching simulator. It combines the strenghts of these two simulators, outperforming them both.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493524]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2323</startPage>
			<endPage>2333</endPage>
			<fileSize>893</fileSize>
			<authors><![CDATA[Santos Filho, Jose Cendido Silveira;Teixeira, Bernardo Vieira;Yacoub, Michel Daoud;de Abreu, Giuseppe Thadeu Freitas;]]></authors>
		</item>
		<item>
			<title><![CDATA[Compressive Sensing for Spread Spectrum Receivers]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493523]]></link>
			<description><![CDATA[With the advent of ubiquitous computing there are two design parameters of wireless communication devices that become very important: power efficiency and production cost. Compressive sensing enables the receiver in such devices to sample below the Shannon-Nyquist sampling rate, which may lead to a decrease in the two design parameters. This paper investigates the use of Compressive Sensing (CS) in a general Code Division Multiple Access (CDMA) receiver. We show that when using spread spectrum codes in the signal domain, the CS measurement matrix may be simplified. This measurement scheme, named Compressive Spread Spectrum (CSS), allows for a simple, effective receiver design. Furthermore, we numerically evaluate the proposed receiver in terms of bit error rate under different signal to noise ratio conditions and compare it with other receiver structures. These numerical experiments show that though the bit error rate performance is degraded by the subsampling in the CS-enabled receivers, this may be remedied by including quantization in the receiver model. We also study the computational complexity of the proposed receiver design under different sparsity and measurement ratios. Our work shows that it is possible to subsample a CDMA signal using CSS and that in one example the CSS receiver outperforms the classical receiver.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493523]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2334</startPage>
			<endPage>2343</endPage>
			<fileSize>556</fileSize>
			<authors><![CDATA[Fyhn, Karsten;Jensen, Tobias L.;Larsen, Torben;Jensen, Soren Holdt;]]></authors>
		</item>
		<item>
			<title><![CDATA[Precoding Methods for the MISO Broadcast Channel with Delayed CSIT]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485026]]></link>
			<description><![CDATA[Recent information theoretic results suggest that precoding on the multi-user downlink MIMO channel with delayed channel state information at the transmitter (CSIT) could lead to data rates much beyond the ones obtained without any CSIT, even in extreme situations when the delayed channel feedback is made totally obsolete by a feedback delay exceeding the channel coherence time. This surprising result is based on the ideas of interference repetition and alignment which allow the receivers to reconstruct information symbols which canceling out the interference completely, making it an optimal scheme in the infinite SNR regime. In this paper, we formulate a similar problem, yet at finite SNR. We propose a first construction for the precoder which matches the previous results at infinite SNR yet reaches a useful trade-off between interference alignment and signal enhancement at finite SNR, allowing for significant performance improvement in practical settings. We present two general precoding methods with arbitrary number of users by means of virtual MMSE and mutual information optimization, achieving good compromise between signal enhancement and interference alignment. Simulation results show substantial improvement due to the compromise between those two aspects.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485026]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>1</startPage>
			<endPage>11</endPage>
			<fileSize>360</fileSize>
			<authors><![CDATA[Yi, Xinping;Gesbert, David;]]></authors>
		</item>
		<item>
			<title><![CDATA[Time-of-Flight-Based Radio Tomography for Device Free Localization]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497007]]></link>
			<description><![CDATA[Due to its ability of realizing device free localization with wireless networks, the radio tomography becomes a promising technique that draws considerable attention. Traditional radio tomography makes use of the received signal strength (RSS) of wireless links to realize location estimation. However, the RSS measurement is particularly sensitive to noise. Inspired by the fact that similar to the RSS, the time-of-flight (TOF) measurement also changes significantly when some objects shadow the wireless link, and the fact that compared with the RSS, the TOF measurement is robust to noise, a novel TOF-based radio tomography is proposed in this paper. With the TOF measurements of the shadowed links as observation information, a modified particle filter algorithm which utilizes the compressive sensing technique to produce the importance distribution of the particle set is proposed, so as to realize localization and tracking with under-sampled measurements by making full use of the space-domain sparse and time-domain gradually changed feature of the location information. The experiments with the 802.15.4a chirp spread spectrum ranging hardware are presented to confirm the proposed scheme.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497007]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2355</startPage>
			<endPage>2365</endPage>
			<fileSize>711</fileSize>
			<authors><![CDATA[Wang, Jie;Gao, Qinghua;Wang, Hongyu;Yu, Yan;Jin, Minglu;]]></authors>
		</item>
		<item>
			<title><![CDATA[Energy Efficiency Optimization for OFDM-Based Cognitive Radio Systems: A Water-Filling Factor Aided Search Method]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6449255]]></link>
			<description><![CDATA[Conventional designs of OFDM-based cognitive radio (CR) systems mainly focus on the system throughput. Since nowdays the energy efficiency (EE) of wireless systems becomes more and more important, this paper intends to improve the system throughput for unit-energy consumption in OFDM-based CR systems. The energy-efficient power allocation problem of OFDM-based CR systems is studied under the total power constraint, the interference power constraint and the rate constraint. Since the energy-efficient power allocation problem is non-convex, in order to find the optimal power allocation at each subcarrier, we propose a novel method named water-filling factors aided search (WFAS) to solve the EE optimization problems with multiple constraints. The global &#x003b5;-optimality and the convergence of the proposed method are presented. The numerical results confirm the theoretical conclusions. The comparisons of the energy-efficient power allocation and the spectrum-efficient power allocation in OFDM-based CR systems are given under different constraints via numerical simulations as well.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6449255]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2366</startPage>
			<endPage>2375</endPage>
			<fileSize>697</fileSize>
			<authors><![CDATA[Mao, Junling;Xie, Gang;Gao, Jinchun;Liu, Yuanan;]]></authors>
		</item>
		<item>
			<title><![CDATA[Opportunistic Channel-Aware Spectrum Access for Cognitive Radio Networks with Interleaved Transmission and Sensing]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489507]]></link>
			<description><![CDATA[Opportunistic spectrum access in a cognitive radio network has been a challenge due to the dynamic nature of spectrum availability and possible collisions between the primary user (PU) and the secondary user (SU). To maximize the spectrum utilization, we propose a spectrum access strategy where SU's packets are interleaved with periodic sensing to detect PU's return. Similar to earlier works on distributed opportunistic scheduling (DOS), we formulate the sensing/probing/access process as a maximum rate-of-return problem in the optimal stopping theory framework and show that the optimal channel access strategy is a pure threshold policy. We consider a realistic channel and system model by taking into account channel fading and sensing errors. We jointly optimize the rate threshold and the packet transmission time to maximize the average throughput of SU, while limiting interference to PU. Our numerical results show that significant throughput gains can be achieved with the proposed scheme compared to other well-known schemes. Our work sheds light on designing DOS protocols for cognitive radio with optimal transmission time that takes into account the dynamic nature of PUs.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489507]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2376</startPage>
			<endPage>2388</endPage>
			<fileSize>1258</fileSize>
			<authors><![CDATA[Tan, Sheu-Sheu;Zeidler, James;Rao, Bhaskar;]]></authors>
		</item>
		<item>
			<title><![CDATA[Urban Location Estimation for Mobile Cellular Networks: A Fuzzy-Tuned Hybrid Systems Approach]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493525]]></link>
			<description><![CDATA[In this paper, we present a plausible approach using time-of-arrival (TOA) measurements for enhancing accuracy and robustness of urban location estimation in mobile cellular networks. The mobile localization problem is cast into the state estimation of a fuzzy-tuned hybrid system. First, we propose a Markov-transitioned fuzzy-tuned hybrid framework for modeling the dynamics of a mobile station (MS), received line-of-sight (LOS)/or non-LOS (NLOS) range measurements, and NLOS bias variations for each base station. The proposed framework also incorporates fuzzy-logic rules for adaptively tuning process noise covariances to model the effects of both mobility variations of the MS. Second, we derive a selective fuzzy-tuned interacting multiple-model (SFT-IMM) algorithm based on the proposed framework. The proposed algorithm can lead to notable performance gains because it can more accurately identify LOS and NLOS conditions and selectively perform fuzzy tuning of process noise covariances. Simulations confirm the performance advantages of the proposed algorithm over other methods such as the Kalman filter and the IMM.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493525]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2389</startPage>
			<endPage>2399</endPage>
			<fileSize>4127</fileSize>
			<authors><![CDATA[Ho, Tan-Jan;]]></authors>
		</item>
		<item>
			<title><![CDATA[Novel Robust Normality Measure for Sparse Data and its Application for Weak Signal Detection]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497008]]></link>
			<description><![CDATA[In this paper, an important statistical signal processing characteristic, namely Gaussianity or normality, is studied. In contrast to the existing Gaussianity measures, we propose a novel measure, which is based on Kullback-Leibler divergence (KLD) between the Gaussian probability density function (PDF) and the generalized Gaussian PDF incorporated with the skewness for the normality test. In our studies, conventional normality tests may often not be robust when they are employed for the non-Gaussian processes with symmetric PDFs. We call this new test as the KGGS test. Our proposed KGGS test is heuristically justified to be more robust than conventional tests for different PDFs, especially symmetric PDFs. A popular application of the normality test for QPSK signal detections is also presented to verify the effectiveness of our proposed technique and the simulation results demonstrate that our new KGGS test would outperform all others even for sparse data samples.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497008]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2400</startPage>
			<endPage>2409</endPage>
			<fileSize>690</fileSize>
			<authors><![CDATA[Lu, Lu;Yan, Kun;Wu, Hsiao-Chun;Chang, Shih Yu;]]></authors>
		</item>
		<item>
			<title><![CDATA[Optimization of Soft Frequency Reuse for Irregular LTE Macrocellular Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497009]]></link>
			<description><![CDATA[Interference management has been recognized by the industry as a key enabler for 4G systems. Emerging technologies include multicarrier systems such as LTE and WiMAX for which effective management of intercell interference is of utmost importance in order to improve the Quality of Service (QoS) at cell edges. Static Intercell Interference Coordination (ICIC) techniques such as Soft Frequency Reuse (SFR) are aimed at alleviating this problem; however the usage of baseline SFR designs (schemes without optimization) only offers tradeoffs between cell edge performance and spectral efficiency and performance is indeed far from optimal as results herein confirm. Thus, this paper presents a novel multiobjective algorithm in order to address this problem and achieve effective optimization of SFR implementations. Results show that the proposed algorithm succeeds in finding good-quality SFR configurations enhancing simultaneously network capacity and cell edge performance while reducing energy consumption with respect to baseline designs and previous proposals.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497009]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2410</startPage>
			<endPage>2423</endPage>
			<fileSize>1860</fileSize>
			<authors><![CDATA[Gonzalez G, David;Garcia-Lozano, Mario;Ruiz Boque, Silvia;Lee, Dong Seop;]]></authors>
		</item>
		<item>
			<title><![CDATA[Cross-Layer QoS-Constrained Optimization of Adaptive Multi-Rate Wireless Systems using Infrastructure-Based Cooperative ARQ]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485027]]></link>
			<description><![CDATA[This research work aims at analyzing the effects of using cooperative-ARQ (CARQ) in wireless relay systems employing AMC at the physical layer and an infinitely persistent type-I Hybrid FEC/CARQ protocol at the DLC layer. To that end, a cross-layer multidimensional discrete-time Markov chain (DTMC)-based queuing model is developed to jointly exploit the capabilities of CARQ and AMC. Based on the stationary state probability distribution of the proposed multidimensional DTMC, closed-form analytical expressions for performance metrics such as average throughput, queue length, packet delay and packet loss rate are derived, and the impact of cooperative relaying on these performance parameters is analyzed. Numerical results confirm the validity of the presented AMC/CARQ cross-layer analytical framework and reveal that the proposed CARQ protocol consistently outperforms the classical Type-I Hybrid FEC/ARQ schemes and provides a noticeable improvement when facing correlated fading channel scenarios.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485027]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2424</startPage>
			<endPage>2435</endPage>
			<fileSize>542</fileSize>
			<authors><![CDATA[Ramis, Jaume;Femenias, Guillem;]]></authors>
		</item>
		<item>
			<title><![CDATA[Optimization of Network Coded MIMO Transmission in Multiple-Access Relay Network]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497003]]></link>
			<description><![CDATA[We consider a multiple-access relay network where multiple source nodes send independent packets to a common destination with the assistance of multiple relay nodes. We assume that the relay nodes are equipped with multiple antennas and are allowed to choose either spatial multiplexing (SM) or transmit diversity (TD) in sending network coded packets. We verify the performance limit of conventional MIMO network coding and propose two optimization schemes to overcome this limit. To this end, we develop an integrated design methodology that jointly optimizes the redundancy offered by network coding at the relays and channel coding at the sources as well as the spatial redundancy offered by multiple antennas in order to minimize the end-to-end outage probability. We show that such joint optimization can provide a significant energy saving.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497003]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2436</startPage>
			<endPage>2444</endPage>
			<fileSize>1714</fileSize>
			<authors><![CDATA[Chun, Young Jin;Kim, Dong In;Kim, Sang Wu;]]></authors>
		</item>
		<item>
			<title><![CDATA[Decision Maker Approaches for Cooperative Spectrum Sensing: Participate or Not Participate in Sensing?]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489501]]></link>
			<description><![CDATA[Cooperative spectrum sensing techniques are mainly based on two different decision approaches, according to the role of the decision maker: i) in the Combining Decision approach, the decision maker combines the sensing information collected from its cooperators, without participating in the sensing of the monitored band; ii) in the Sensing &amp; Combining Decision approach, the decision maker combines both the sensing information of its cooperators and its own local sensing information. The choice of the decision approach deeply affects the performance of any cooperative spectrum sensing technique. However, the key issue of choosing the decision approach that guarantees the higher detection accuracy independently of the underlying cooperative sensing architecture is still an open problem. For this, in this paper, the criteria for an effective decision-approach selection are analytically derived with the object of maximizing the detection accuracy in presence of realistic channel propagation effects. Specifically, through a theoretical analysis, it is proven that the detection accuracy exhibits a threshold behavior as a function of the adopted decision approach. Closed-form expressions of such a threshold are analytically derived and practical insights for the decision approach choice are provided. Finally, the theoretical analysis is validated through simulations.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489501]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2445</startPage>
			<endPage>2457</endPage>
			<fileSize>688</fileSize>
			<authors><![CDATA[Cacciapuoti, Angela Sara;Caleffi, Marcello;Paura, Luigi;Savoia, Roberto;]]></authors>
		</item>
		<item>
			<title><![CDATA[Performance of Systematic RRNS Based Space-Time Block Codes with Probability-Aware Adaptive Demapping]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489502]]></link>
			<description><![CDATA[In this paper, we propose a novel design of concatenated Space-Time Block Codes (STBCs) using Systematic Redundant Residue Number System (RRNS) codes. The link between residues and complex signal constellations is optimized by incorporating the "Direct Mapping", "Prior probability based Distance Aware Mapping" and "Indirect Mapping" schemes. We analytically quantify the upper bounds on the codeword and bit error probabilities of Systematic RRNS-STBC and characterize the achievable coding and diversity gains assuming maximum likelihood decoding (MLD). We propose an Adaptive M-ary Demapping scheme for ML decoding, which exploits the RRNS code structure to decrease complexity and provide further performance improvement over the Distance Aware Mapping scheme. It is shown that Indirect Mapping, when used for RRNS coding schemes can offer more efficient transmission and performance than naive M-ary mapping. It is also seen that Systematic RRNS-STBC codes provide superior performance compared to Non-systematic RRNS-STBC, for the same code parameters, owing to more efficient binary to residue mapping.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489502]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2458</startPage>
			<endPage>2469</endPage>
			<fileSize>508</fileSize>
			<authors><![CDATA[Sengupta, Avik;Natarajan, Balasubramaniam;]]></authors>
		</item>
		<item>
			<title><![CDATA[Joint Spectrum Sensing and Access Evolutionary Game in Cognitive Radio Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489503]]></link>
			<description><![CDATA[Many spectrum sensing methods and dynamic access algorithms have been proposed to improve the secondary users' opportunities of utilizing the primary users' spectrum resources. However, few of them have considered to integrate the design of spectrum sensing and access algorithms together by taking into account the mutual influence between them. In this paper, we propose to jointly analyze the spectrum sensing and access problem by studying two scenarios: synchronous scenario where the primary network is slotted and non-slotted asynchronous scenario. Due to selfish nature, secondary users tend to act selfishly to access the channel without contribution to the spectrum sensing. Moreover, they may take out-of-equilibrium strategies because of the uncertainty of others' strategies. To model the complicated interactions among secondary users, we formulate the joint spectrum sensing and access problem as an evolutionary game and derive the evolutionarily stable strategy (ESS) that no one will deviate from. Furthermore, we design a distributed learning algorithm for the secondary users to converge to the ESS. With the proposed algorithm, each secondary user senses and accesses the primary channel with the probabilities learned purely from its own past utility history, and finally achieves the desired ESS. Simulation results shows that our system can quickly converge to the ESS and such an ESS is robust to the sudden unfavorable deviations of the selfish secondary users.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6489503]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2470</startPage>
			<endPage>2483</endPage>
			<fileSize>990</fileSize>
			<authors><![CDATA[Jiang, Chunxiao;Chen, Yan;Gao, Yang;Liu, K.J.Ray;]]></authors>
		</item>
		<item>
			<title><![CDATA[Offloading in Heterogeneous Networks: Modeling, Analysis, and Design Insights]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497002]]></link>
			<description><![CDATA[Pushing data traffic from cellular to WiFi is an example of inter radio access technology (RAT) offloading. While this clearly alleviates congestion on the over-loaded cellular network, the ultimate potential of such offloading and its effect on overall system performance is not well understood. To address this, we develop a general and tractable model that consists of M different RATs, each deploying up to K different tiers of access points (APs), where each tier differs in transmit power, path loss exponent, deployment density and bandwidth. Each class of APs is modeled as an independent Poisson point process (PPP), with mobile user locations modeled as another independent PPP, all channels further consisting of i.i.d. Rayleigh fading. The distribution of rate over the entire network is then derived for a weighted association strategy, where such weights can be tuned to optimize a particular objective. We show that the optimum fraction of traffic offloaded to maximize SINR coverage is not in general the same as the one that maximizes rate coverage, defined as the fraction of users achieving a given rate.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497002]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2484</startPage>
			<endPage>2497</endPage>
			<fileSize>964</fileSize>
			<authors><![CDATA[Singh, Sarabjot;Dhillon, Harpreet S.;Andrews, Jeffrey G.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Full-Duplex Cooperative Cognitive Radio with Transmit Imperfections]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493535]]></link>
			<description><![CDATA[This paper studies the cooperation between a primary system and a cognitive system in a cellular network where the cognitive base station (CBS) relays the primary signal using amplify-and-forward or decode-and-forward protocols, and in return it can transmit its own cognitive signal. While the commonly used half-duplex (HD) assumption may render the cooperation less efficient due to the two orthogonal channel phases employed, we propose that the CBS can work in a full-duplex (FD) mode to improve the system rate region. The problem of interest is to find the achievable primary-cognitive rate region by studying the cognitive rate maximization problem. For both modes, we explicitly consider the CBS transmit imperfections, which lead to the residual self-interference associated with the FD operation mode. We propose closed-form solutions or efficient algorithms to solve the problem when the related residual interference power is non-scalable or scalable with the transmit power. Furthermore, we propose a simple hybrid scheme to select the HD or FD mode based on zero-forcing criterion, and provide insights on the impact of system parameters. Numerical results illustrate significant performance improvement by using the FD mode and the hybrid scheme.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493535]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2498</startPage>
			<endPage>2511</endPage>
			<fileSize>563</fileSize>
			<authors><![CDATA[Zheng, Gan;Krikidis, Ioannis;Ottersten, Bjdotrm orn;]]></authors>
		</item>
		<item>
			<title><![CDATA[A Byzantine Attack Defender in Cognitive Radio Networks: The Conditional Frequency Check]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485035]]></link>
			<description><![CDATA[Security concerns are raised for collaborative spectrum sensing due to its vulnerabilities to the potential attacks from malicious secondary users. Most existing malicious user detection methods are reputation-based, which become incapable when the malicious users dominate the network. On the other hand, although Markovian models characterize the spectrum state behavior more precisely, there is a scarcity of malicious user detection methods which fully explore this feature. In this paper, a new malicious user detection method using two proposed conditional frequency check (CFC) statistics is developed under the Markovian model for the spectrum state. With the assistance of one trusted user, the proposed method can achieve high malicious user detection accuracy (&#x02265; 95%) for arbitrary percentage of malicious users that may even be equipped with more advanced sensing devices, and can thus improve the collaborative spectrum sensing performance significantly. Simulation results are provided to verify the theoretical analysis and effectiveness of the proposed method.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6485035]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2512</startPage>
			<endPage>2523</endPage>
			<fileSize>1023</fileSize>
			<authors><![CDATA[He, Xiaofan;Dai, Huaiyu;Ning, Peng;]]></authors>
		</item>
		<item>
			<title><![CDATA[Spectrum Sharing with Limited Channel Feedback]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493533]]></link>
			<description><![CDATA[In this paper, an underlay spectrum sharing scheme is proposed where both primary and secondary users are discrete power-rate adaptive systems with limited feedback from receivers. By receiving secondary and overhearing primary quantized channel quality information from the secondary receiver and primary receiver, respectively, the secondary transmitter adapts its resource allocation to the current channel quality by selecting a proper power-rate pair from a pre-designed secondary quantization codebook. The secondary quantization codebook is designed to maximize the secondary average rate subject to the primary rate loss constraint and the average secondary transmit power constraint, which is discussed in three cases when different amount of side information of the primary codebook and the cross interference link are available at the secondary receiver side. Differential Evolution algorithm is employed to provide the global optimal solutions to the proposed secondary quantization codebook optimization problems. Numerical results show that, by introducing the secondary feedback, the secondary throughput is greatly improved. Furthermore, more secondary feedback bits or more primary side information result in better secondary performance.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6493533]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2524</startPage>
			<endPage>2532</endPage>
			<fileSize>329</fileSize>
			<authors><![CDATA[Wang, Zhe;Zhang, Wei;]]></authors>
		</item>
		<item>
			<title><![CDATA[Energy-Efficient Transmissions of Bursty Data Packets with Strict Deadlines over Time-Varying Wireless Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497021]]></link>
			<description><![CDATA[We develop a novel approach to energy-efficient transmissions with arbitrary packet arrival process and strict delay constraints over time-varying wireless channels. When the arrivals, deadlines, and channel realizations are known a priori, we formulate the problem as a convex program. Relying on the specific structure of the optimality conditions, we put forth an efficient algorithm with a linear computational complexity in the order of constraint number to find the (offline) optimal rate control strategy. It is revealed that the power usage under the optimal policy admits a multi-level water-filling form, where the determination of the multiple water-levels can be visualized by the trajectory of letting a string tie its two ends and then taut between what we call the "water" arrival and departure curves. Guided by the optimal strategy, development of energy-efficient online schedules in practical systems is discussed. Numerical results are provided to demonstrate the merits of the proposed novel scheme.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6497021]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>2533</startPage>
			<endPage>2543</endPage>
			<fileSize>448</fileSize>
			<authors><![CDATA[Wang, Xin;Li, Zhaoquan;]]></authors>
		</item>
		<item>
			<title><![CDATA[Staff list]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6521484]]></link>
			<description><![CDATA[Provides a listing of current staff, committee members and society officers.]]></description>
			<pubDate><![CDATA[May  2013]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6521484]]></guid>
			<volume>12</volume>
			<issue>5</issue>
			<startPage>c3</startPage>
			<endPage>c3</endPage>
			<fileSize>60</fileSize>
			<authors><![CDATA[]]></authors>
		</item>
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