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	<channel>
		<title><![CDATA[ Communications, IEEE Transactions on - new TOC ]]></title>
		<link>http://ieeexplore.ieee.org</link>
		<description>TOC Alert for Publication# 26 </description>
		<year>2009</year>
		<month>June     </month>
		<day>19</day>
		<item>
			<title><![CDATA[IEEE Transactions on Communications]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939205]]></link>
			<description><![CDATA[ ]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939205]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>c1</startPage>
			<endPage>c1</endPage>
			<fileSize>64</fileSize>
			<authors><![CDATA[]]></authors>
		</item>
		<item>
			<title><![CDATA[Rate Variable, Multi-Binary Turbo Codes with Controlled Error-Floor]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939206]]></link>
			<description><![CDATA[In this letter we propose rate variable turbo codes based on the parallel concatenation of tailbiting Recursive Systematic multi-binary (m-ary) convolutional codes. Rate variability is not achieved by puncturing, which can have adverse effects on the minimum distance of the code. Using a variable number of input lines of the encoder, we obtain several different overall rates ranging from 1/2 to 7/8. The most suitable Soft-In- Soft-Out decoding algorithm for these turbo codes is based on the Dual Reciprocal Code, which is very efficient for high rate codes. A particular interleaver design, namely the ¿backbone¿ interleaver, guarantees a high Hamming weight in codewords with information weight 2 and 3, as well as good minimum distances and fairly low multiplicities for higher information weights. Therefore, these codes have very low error floors.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939206]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1209</startPage>
			<endPage>1214</endPage>
			<fileSize>225</fileSize>
			<authors><![CDATA[Ferrari, M.;Bellini, S.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Performance Bounds for Unequal Error Protecting Turbo Codes]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939207]]></link>
			<description><![CDATA[In many communications systems, data can be divided into different importance levels. For these systems, unequal error protection (UEP) techniques are used to guarantee lower BER for the more important classes. In particular, if the precise characteristics of the channel are not known, UEP can be used to recover the more important classes even in poor receiving conditions. In this paper, we derive bounds on the performance of unequal error protecting turbo codes. These bounds serve as an important tool in predicting the performance of these codes. In order to derive the bounds, we introduce the notion of UEPuniform interleaver which is a random interleaver that does not change the order of classes in the turbo code frame. We also present a method to derive the weight enumerating function for UEP turbo codes.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939207]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1215</startPage>
			<endPage>1220</endPage>
			<fileSize>279</fileSize>
			<authors><![CDATA[Ayd¿nl¿k, M.;Salehi, M.;]]></authors>
		</item>
		<item>
			<title><![CDATA[A New Scheme to Determine the Weight Distributions of Binary Extended Quadratic Residue Codes]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939208]]></link>
			<description><![CDATA[This letter proposes a novel scheme which consists of a weight-counting algorithm, the combinatorial designs of the Assmus-Mattson theorem, and the weight polynomial of Gleason¿s theorem to determine the weight distributions of binary extended quadratic residue codes. As a consequence, the weight distributions of binary (138, 69, 22) and (168, 84, 24) extended quadratic residue codes are given.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939208]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1221</startPage>
			<endPage>1224</endPage>
			<fileSize>157</fileSize>
			<authors><![CDATA[Trieu-Kien Truong;Chong-Dao Lee;Yaotsu Chang;Wen-Ku Su;]]></authors>
		</item>
		<item>
			<title><![CDATA[Practical Interleavers for Repeat¿Accumulate Codes]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939209]]></link>
			<description><![CDATA[In this paper we design practical interleavers for regular, systematic repeat¿accumulate (RA) codes. The new interleavers, which we call L-type and modified L-type interleavers, are deterministic, described by a single parameter, and straightforward to implement. Despite their simple description, the new interleavers are shown to perform equally as well as, or better than, traditional interleavers over a wide range of code lengths and rates.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939209]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1225</startPage>
			<endPage>1228</endPage>
			<fileSize>285</fileSize>
			<authors><![CDATA[Johnson, S.J.;Weller, S.R.;]]></authors>
		</item>
		<item>
			<title><![CDATA[A Hybrid Decoder for Block Turbo Codes]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939210]]></link>
			<description><![CDATA[We propose a novel iterative decoder for block turbo codes (BTCs). The proposed decoder combines soft-input/softoutput (SISO) and hard-input/hard-output (HIHO) constituent decoders in order to obtain better error performance and reduce the computational complexity compared to classical BTC decoders. We show that the new decoder, called ¿hybrid decoder¿, offers a better complexity/performance tradeoff than a classical BTC decoder.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939210]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1229</startPage>
			<endPage>1232</endPage>
			<fileSize>198</fileSize>
			<authors><![CDATA[Al-Dweik, A.;Le Goff, S.;Sharif, B.;]]></authors>
		</item>
		<item>
			<title><![CDATA[High Rate CPFSK Space-Time Trellis Codes]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939211]]></link>
			<description><![CDATA[Space-time trellis coding is an established diversity technique that reduces the effects of multipath fading over wireless communication channels. Here, we consider high rate space-time trellis codes (STTC) with continuous phase frequency shift keying (CPFSK). We present optimized rate-2/3 STTC implemented with 3 transmit antennas. These codes provide system throughputs of 4 and 6 bits per channel use with 4-ary and 8-ary CPFSK respectively. Simulated error rate performance of the optimized codes with receive diversity is presented. We show that although the schemes do not achieve full transmit diversity, they provide excellent coding gains compared to full rank schemes that have equivalent throughput, but higher order modulations and greater complexity.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939211]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1233</startPage>
			<endPage>1236</endPage>
			<fileSize>246</fileSize>
			<authors><![CDATA[Maw, R.L.;Taylor, D.P.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Performance of Optimum and Suboptimum Receivers for Space-Time Coded Systems in Correlated Fading]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939212]]></link>
			<description><![CDATA[We consider a space-time coded system in a correlated Rayleigh flat fading environment with imperfect channel estimation. Two receiver structures are considered: a suboptimum receiver and the optimum maximum likelihood receiver. The system performance of both receivers is analyzed in terms of the pairwise error probability.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939212]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1237</startPage>
			<endPage>1241</endPage>
			<fileSize>222</fileSize>
			<authors><![CDATA[Mallik, R.K.;Garg, P.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Effect of MMSE Channel Estimation on BER Performance of Orthogonal Space-Time Block Codes in Rayleigh Fading Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939213]]></link>
			<description><![CDATA[We present a simple closed-form expression for the BER of orthogonal space-time block codes (OSTBCs) with MMSE channel estimation, assuming PAM and QAM constellations and flat Rayleigh block fading. The BER expression is exact for a certain class of OSTBCs, and provides a very accurate approximation for other OSTBCs.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939213]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1242</startPage>
			<endPage>1245</endPage>
			<fileSize>236</fileSize>
			<authors><![CDATA[Jacobs, L.;Moeneclaey, M.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Decision-Directed Channel Estimation and High I/Q Imbalance Compensation in OFDM Receivers]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939214]]></link>
			<description><![CDATA[Direct-conversion architectures suffer from the mismatch between the In-phase (I) and the Quadrature-phase (Q) branches, commonly called I/Q imbalance. Even low I/Q imbalances imply poor performance of Orthogonal Frequency Division Multiplexing (OFDM) systems. In this paper, we propose a new algorithm that uses both training and data symbols in a decision-directed fashion to jointly estimate the channel and compensate for high receiver I/Q imbalance. Simulation results show that our method can compensate for high I/Q imbalance values and also estimate a frequency selective channel.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939214]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1246</startPage>
			<endPage>1249</endPage>
			<fileSize>281</fileSize>
			<authors><![CDATA[Traverso, S.;Ariaudo, M.;Fijalkow, I.;Gautier, J.-L.;Lereau, C.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Signal Detection for Distributed Space-Time Block Coding: 4 Relay Nodes under Quasi-Synchronisation]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939215]]></link>
			<description><![CDATA[Most research on Distributed Space-Time Block Coding (D-STBC) has so far focused on the case of 2 relay nodes and assumed that the relay nodes are perfectly synchronised at the symbol level. This paper applies STBC to 4-relaynode systems under quasi-synchronisation and derives a new detector based on parallel interference cancellation, which proves to be very effective in suppressing the impact of imperfect synchronisation.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939215]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1250</startPage>
			<endPage>1255</endPage>
			<fileSize>332</fileSize>
			<authors><![CDATA[Zheng, F.-C.;Burr, A.G.;Olafsson, S.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Spectral Efficiency and Optimal Medium Access Control of Random Access Systems over Large Random Spreading CDMA]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939216]]></link>
			<description><![CDATA[This paper analyzes the spectral efficiency as a function of medium access control (MAC) for large random spreading CDMA random access systems that employ a linear receiver. It is shown that located at higher than the physical layer, MAC along with spreading and power allocation can effectively perform spectral efficiency maximization and near-far mitigation.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939216]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1256</startPage>
			<endPage>1260</endPage>
			<fileSize>235</fileSize>
			<authors><![CDATA[Sun, Y.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Performance Comparison of Non-Data-Aided Symbol Timing-Error Detection for the Raised-Cosine and ¿Better Than¿ Raised-Cosine Pulses]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939217]]></link>
			<description><![CDATA[The performance of non-data-aided feedback-loop symbol timing synchronization operating with the raised-cosine (RC) and the ¿better than¿ raised-cosine (BTRC) pulses is investigated. The individual effects of additive channel noise, selfnoise, and their product on the variance of the jitter are studied for the two pulses. The BTRC pulse is shown to have better synchronization performance than the conventional RC pulse, except when the signal-to-noise ratio is very large and the excess bandwidth is large. Furthermore, in the case where a prefilter removing self-noise is employed, the BTRC pulse always has a performance gain over the RC pulse. The gain is, for example, as much as 1.4 dB for excess bandwidth of 0.35 without a prefilter and is larger when the excess bandwidth is smaller or a prefilter is employed.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939217]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1261</startPage>
			<endPage>1264</endPage>
			<fileSize>200</fileSize>
			<authors><![CDATA[Lee, S.J.;Beaulieu, N.C.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Symbol Timing Recovery for CPM with Correlated Data Symbols]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939218]]></link>
			<description><![CDATA[We consider symbol timing recovery for continuous phase modulations (CPMs) with correlated data symbols. A popular example of such a scheme is shaped offset quadrature phase-shift keying (SOQPSK). We propose an extension to an existing non-data-aided (blind) timing error detector (TED) to make it compatible with such modulation schemes. The merits of the modified TED are demonstrated by comparing its performance with and without taking the data correlation into account. As a further modification, we show that a quantization scheme can be used to yield an extremely low-complexity version of the system with only negligible performance losses. The Scurve of the proposed quantized TED is given, which rules out the existence of false lock points. The proposed scheme shows great promise in a wide range of applications due to its low complexity, its lack of false lock points, and its blind nature; such applications include timing recovery for noncoherent detection schemes and false lock detectors.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939218]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1265</startPage>
			<endPage>1270</endPage>
			<fileSize>278</fileSize>
			<authors><![CDATA[Chandran, P.;Perrins, E.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Accurate Approximations to the Sum of Generalized Random Variables and Applications in the Performance Analysis of Diversity Systems]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939219]]></link>
			<description><![CDATA[Accurate closed-form approximations to the sum of independent identically distributed &#x003B7;-&#x003BC; and &#x003BA;-&#x003BC; random variables are provided. The proposed approximations turn out to be simple, precise, and useful for obtaining important performance metrics of communications systems where sums of variates arise. In particular, average bit error rate and level crossing rate of multibranch equal-gain combining receivers are attained to illustrate the applicability of the approximations. Some sample examples show that the intricate exact solution and the simple approximate expressions yield results that are almost indistinguishable from each other.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939219]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1271</startPage>
			<endPage>1274</endPage>
			<fileSize>374</fileSize>
			<authors><![CDATA[Da Costa, D.B.;Yacoub, M.D.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Efficient Architectures for Multiuser FMT Systems and Application to Power Line Communications]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939220]]></link>
			<description><![CDATA[In this letter we study filtered multitone modulation (FMT) for broadband multiuser power line communications. We address the implementation problem, and we derive a novel efficient digital implementation of both the synthesis and the analysis filter bank. A simple fractionally spaced multiuser receiver is also proposed.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939220]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1275</startPage>
			<endPage>1279</endPage>
			<fileSize>505</fileSize>
			<authors><![CDATA[Tonello, A.M.;Pecile, F.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Combining Beamforming and Space-Time Coding Using Noisy Quantized Feedback]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939221]]></link>
			<description><![CDATA[The goal of combining beamforming and spacetime coding is to obtain full-diversity order and to provide additional received power (array gain) compared to conventional space-time codes. In this work, a class of code constellations is proposed, called generalized partly orthogonal designs (PODs) and both high-rate and low-rate feedback information is incorporated with possible feedback errors. A binary symmetric channel (BSC) model characterizes feedback errors. Two cases are studied: first, when the BSC bit error probability is known a priori to the transmission ends, and second, when it is not known exactly. Based on a minimum pairwise error probability (PEP) design criterion, we design a channel optimized vector quantizer (COVQ) for feedback information and a precoder matrix codebook to adjust the transmission codewords. The attractive property of our combining scheme is that it converges to conventional space-time coding with low-rate and erroneous feedback and to directional beamforming with high-rate and error-free feedback. This scheme also shows desirable robustness against feedback channel modeling mismatch.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939221]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1280</startPage>
			<endPage>1286</endPage>
			<fileSize>396</fileSize>
			<authors><![CDATA[Ekbatani, S.;Jafarkhani, H.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Comments on ¿Probability Distributions for the Number of Radio Transceivers which can Communicate with One Another¿]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939222]]></link>
			<description><![CDATA[We discuss the correctness of one of the main results of [1] about the probability density function of the distance between two audible nodes in an infinite 2-dimensional scenario. We prove that result [1, eq. (7)] is wrong and derive a more general expression, which is valid for an infinite d¿dimensional area. It is worth noting that, although the results on the distribution of the distance between two nodes are wrong, the other results of [1], and in particular the fact that the number of audible nodes in an arbitrary area is a Poisson r.v. is correct.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939222]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1287</startPage>
			<endPage>1289</endPage>
			<fileSize>168</fileSize>
			<authors><![CDATA[Zanella, A.;Stramazzotti, M.;Fabbri, F.;Salbaroli, E.;Dardari, D.;Verdone, R.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Genetic Algorithm Aided Design of Component Codes for Irregular Variable Length Coding]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939223]]></link>
			<description><![CDATA[In this paper we propose a novel Real-Valued Free Distance Metric (RV-FDM) for comparing the error correction capabilities of Variable Length Error Correction (VLEC) codebooks that have the same integer-valued free distance lower bounds. We demonstrate that VLEC codebooks having higher RV-FDMs tend to have EXtrinsic Information Transfer (EXIT) functions with more pronounced `S¿-shapes. Furthermore, we show that higher-accuracy EXIT chart matching can be achieved if the component EXIT functions of an irregular code exhibit more variety. This motivates the employment of our novel genetic algorithm for designing the component VLEC codes of irregular variable length coding, that have particular EXIT functions, in addition to exhibiting desirable bit entropies and decoding complexities.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939223]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1290</startPage>
			<endPage>1297</endPage>
			<fileSize>452</fileSize>
			<authors><![CDATA[Maunder, R.G.;Hanzo, L.;]]></authors>
		</item>
		<item>
			<title><![CDATA[High Performance Non-Binary Quasi-Cyclic LDPC Codes on Euclidean Geometries LDPC Codes on Euclidean Geometries]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939224]]></link>
			<description><![CDATA[This paper presents algebraic methods for constructing high performance and efficiently encodable non-binary quasi-cyclic LDPC codes based on flats of finite Euclidean geometries and array masking. Codes constructed based on these methods perform very well over the AWGN channel. With iterative decoding using a Fast Fourier Transform based sum-product algorithm, they achieve significantly large coding gains over Reed-Solomon codes of the same lengths and rates decoded with either algebraic hard-decision Berlekamp-Massey algorithm or algebraic soft-decision Kötter-Vardy algorithm. Due to their quasi-cyclic structure, these non-binary LDPC codes on Euclidean geometries can be encoded using simple shiftregisters with linear complexity. Structured non-binary LDPC codes have a great potential to replace Reed-Solomon codes for some applications in either communication or storage systems for combating mixed types of noise and interferences.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939224]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1298</startPage>
			<endPage>1311</endPage>
			<fileSize>809</fileSize>
			<authors><![CDATA[Zhou, B.;Kang, J.;Tai, Y.Y.;Lin, S.;Ding, Z.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Doubly Generalized LDPC Codes over the AWGN Channel]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939225]]></link>
			<description><![CDATA[In this paper, the design of doubly generalized low-density parity-check (DGLDPC) codes is proposed. This approach generalizes the structure of LDPC codes at both check and variable nodes. The performance of DGLDPC codes over the AWGN channel is analyzed using EXIT charts. Combined with differential evolution optimization, this analysis provides thresholds for DGLDPC codes that are better than that of LDPC and GLDPC codes with the same maximum variable degree. These theoretical thresholds are verified via simulations. Furthermore DGLDPC codes exhibit a lower error floor compared with their LDPC and GLDPC counterparts.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939225]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1312</startPage>
			<endPage>1319</endPage>
			<fileSize>386</fileSize>
			<authors><![CDATA[Wang, Y.;Fossorier, M.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Construction of Near-Optimum Burst Erasure Correcting Low-Density Parity-Check Codes]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939226]]></link>
			<description><![CDATA[In this paper, a simple and effective tool for the design of low-density parity-check (LDPC) codes for iterative correction of bursts of erasures is presented. The design method consists of starting from the parity-check matrix of an LDPC code and developing an optimized parity-check matrix, with the same performance over the memoryless erasure channel, and suitable also for the iterative correction of single erasure bursts. The parity-check matrix optimization is performed by an algorithm called pivot searching and swapping (PSS) algorithm. It executes permutations of carefully chosen columns of the parity-check matrix, after a local analysis of particular variable nodes called stopping set pivots. This algorithm can be in principle applied to any LDPC code. If the input parity-check matrix is designed to achieve a good performance over the memoryless erasure channel, then the code obtained after the application of the algorithm provides a good joint correction of independent erasures and single erasure bursts. Numerical results are provided in order to show the algorithm effectiveness when applied to different categories of LDPC codes.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939226]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1320</startPage>
			<endPage>1328</endPage>
			<fileSize>366</fileSize>
			<authors><![CDATA[Paolini, E.;Chiani, M.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Multistream Faster than Nyquist Signaling]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939227]]></link>
			<description><![CDATA[We extend Mazo¿s concept of faster-than-Nyquist (FTN) signaling to pulse trains that modulate a bank of subcarriers, a method called two dimensional FTN signaling. The signal processing is similar to orthogonal frequency division multiplex (OFDM) transmission but the subchannels are not orthogonal. Despite nonorthogonal pulses and subcarriers, the method achieves the isolated-pulse error performance; it does so in as little as half the bandwidth of ordinary OFDM. Euclidean distance properties are investigated for schemes based on several basic pulses. The best have Gaussian shape. An efficient distance calculation is given. Concatenations of ordinary codes and FTN are introduced. The combination achieves the outer code gain in as little as half the bandwidth. Receivers must work in two dimensions, and several iterative designs are proposed for FTN with outer convolutional coding.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939227]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1329</startPage>
			<endPage>1340</endPage>
			<fileSize>411</fileSize>
			<authors><![CDATA[Rusek, F.;Anderson, J.B.;]]></authors>
		</item>
		<item>
			<title><![CDATA[On the Outage Capacity of a Practical Decoder Accounting for Channel Estimation Inaccuracies]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939228]]></link>
			<description><![CDATA[The optimal decoder achieving the outage capacity under imperfect channel estimation is investigated. First, by searching into the family of nearest neighbor decoders, which can be easily implemented on most practical coded modulation systems, we derive a decoding metric that minimizes the average of the transmission error probability over all channel estimation errors. Next, we specialize our general expression to obtain the corresponding decoding metric for fading MIMO channels. According to the notion of Estimation-induced outage (EIO) capacity introduced in our previous work and assuming a block Rayleigh-fading channel, we characterize the maximal achievable information rates using Gaussian codebooks associated to the proposed decoder. These achievable rates are compared to the rates achieved by the classical mismatched maximumlikelihood (ML) decoder and the ultimate limits given by the EIO capacity. Numerical results show that the derived metric provides significant gains, in terms of achievable EIO rates and bit error rate (BER), in a bit interleaved coded modulation (BICM) framework, without introducing any additional decoding complexity. However, the achievable rates of such metric are still far from the EIO capacity.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939228]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1341</startPage>
			<endPage>1350</endPage>
			<fileSize>536</fileSize>
			<authors><![CDATA[Piantanida. P,;Sadough, S.M-S.;Duhamel, P.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Mapping Rearrangement for HARQ Based on Low-Order Modulation]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939229]]></link>
			<description><![CDATA[In this paper we consider hybrid automatic repeat request transmission based on binary phase shift keying modulation. Our objective is to improve the performance of the retransmissions, keeping at the same time the complexity and the performance of the first transmission unaltered.We conclude that the so-called mapping rearrangement (MR) may considerably improve the performance if multi-dimensional modulation is applied. We evaluate the theoretical limits of bit-interleaved coded modulation withMR, verify the functioning of the practical coding scheme, and propose to improve the performance via iterative detection-decoding (BICM-ID) which brings considerable gains. In particular, for high coding rates, a 4 dB SNR gain over transmission without MR may be achieved.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939229]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1351</startPage>
			<endPage>1358</endPage>
			<fileSize>511</fileSize>
			<authors><![CDATA[Szczecinski, L.;Ceron, A.;Feick, R.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Effects of Non-Identical Rayleigh Fading on Differential Unitary Space-Time Modulation]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939230]]></link>
			<description><![CDATA[Non-identical fading distribution in a multiple-input multiple-output (MIMO) channel, including unequal average channel gains and fade rates, often occurs when antennas are not co-located. In this paper, we present an analytical study of the effects of non-identical Rayleigh fading on the error performance of differential unitary space-time modulation (DUSTM). The fading processes for different transmit-receive antenna pairs are assumed to be independent and time-variant. We find that the maximum-likelihood (ML) differential detector of DUSTM over such channels is involved except for differential cyclic group codes. The conventional detector is proved to be asymptotically optimal in the limit of high signal-to-noise ratio (SNR) over static fading channels. Applying the distribution of quadratic forms of Gaussian vectors, we then derive closed-form expressions for the exact error probabilities of two specific unitary classes, namely, cyclic group codes and orthogonal codes. Simple and useful asymptotic bounds on error probabilities are also obtained. Our analysis leads to the following general findings: (1) equal power allocation is asymptotically optimal, and (2) non-identical channel gain distribution degrades the error performance. Finally, we also introduce a water-filling based power allocation to exploit the transmit non-identical fading statistics.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939230]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1359</startPage>
			<endPage>1369</endPage>
			<fileSize>565</fileSize>
			<authors><![CDATA[Tao, M.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Rate Balancing in Multiuser MIMO OFDM Systems]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939231]]></link>
			<description><![CDATA[Recently, the capacity region of the Gaussian broadcast channel has been characterized. For a given transmit power constraint, those points on the boundary of the capacity region can be regarded as the set of optimal operational points. The present work addresses the problem of selecting the point within this set that satisfies given constraints on the ratios between rates achieved by the different users in the network. This problem is usually known as rate balancing. To this end, the optimum iterative approach for general MIMO channels is revisited and adapted to an OFDM transmission scheme. Specifically, an algorithm is proposed that exploits the structure of the OFDM channel and whose convergence speed is essentially insensitive to the number of subcarriers. This is in contrast to a straightforward extension of the general MIMO algorithm to an OFDM scheme. Still, relatively high complexity and the need of a time-sharing policy to reach certain rates are at least two obstacles for a practical implementation of the optimum solution. Based on a novel decomposition technique for broadcast channels a suboptimum non-iterative algorithm is introduced that does not require time-sharing and very closely approaches the optimum solution.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939231]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1370</startPage>
			<endPage>1380</endPage>
			<fileSize>515</fileSize>
			<authors><![CDATA[Tejera, P.;Utschick, W.;Nossek, J.A.;Bauch, G.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Fair Resource Allocation for the Gaussian Broadcast Channel with ISI]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939232]]></link>
			<description><![CDATA[We consider fair resource allocation in Gaussian frequency-division broadcast channel with intersymbol interference. The goal is to allocate power and subchannels in a way such that proportional fairness is achieved. We show that the subchannel allocation problem is NP-hard. If multiple users are allowed to time-share a subchannel, the relaxed problem is equivalent to the cake cutting problem and can be efficiently solved. For the joint power and subchannel allocation problem, we propose an iterative method, which solves the power allocation problem and subchannel allocation problem alternately. Simulation results show that its performance is nearly optimal.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939232]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1381</startPage>
			<endPage>1389</endPage>
			<fileSize>417</fileSize>
			<authors><![CDATA[Sung, C.W.;Shum, K.W.;Ng, C.Y.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Optimal Rate-Reliability-Delay Tradeoff in Networks with Composite Links]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939233]]></link>
			<description><![CDATA[Networks need to accommodate diverse applications with different Quality-of-Service (QoS) requirements. New ideas at the physical layer are being developed for this purpose, such as diversity embedded coding, which is a technique that combines high rates with high reliability. We address the problem of how to fully utilize different rate-reliability characteristics at the physical layer to support different types of traffic over a network and to jointly maximize their utilities. We set up a new framework based on utility maximization for networks with composite links, meaning that each link consists of sub-links that can attain different rate-reliability characteristics simultaneously. We incorporate delay, in addition to rate and reliability, into the utility functions. To accommodate different types of traffic, we propose distributed algorithms converging to the optimal rate-reliability-delay tradeoff based on capacity division and priority queueing. Numerical results show that compared with traditional codes, the new codes can provide higher network utilities for all traffic types simultaneously. The results also show that priority queueing achieves higher network utility than capacity division.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939233]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1390</startPage>
			<endPage>1401</endPage>
			<fileSize>655</fileSize>
			<authors><![CDATA[Li, Y.;Chiang, M.;Calderbank, A.R.;Diggavi, S.N.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Optimal Decoding and Performance Analysis of a Noisy Channel Network with Network Coding]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939234]]></link>
			<description><![CDATA[We investigate sink decoding approaches and performance analysis for a network with intermediate node encoding (coded network). The network consists of statistically independent noisy channels. The sink bit error probability (BEP) is the performance measure. First, we investigate soft-decision decoding without statistical information on the upstream channels (the channels not directly connected to the sink). Numerical results show that the decoder cannot significantly improve the performance from a hard-decision decoder. We develop union bounds for analysis. The bounds show the asymptotic (regarding SNR: signal-to-noise ratio) performance of the decoder. Using statistical information about the upstream channels, we can find the error patterns of final hop channels (channels directly connected to sinks).With the error patterns, maximum-likelihood (ML) decoding can be performed, and a significant improvement in the BEP is obtained. To evaluate the union bound for the ML decoder, we use an equivalent point procedure. It is reduced to the least-squares problem with a linear constraint in the mediumto- high SNR region. With deterministic knowledge of the errors in the upstream channels, a genie-aided decoder can further improve the performance. We give the union bound for the genie decoder, which is straightforward to evaluate. By analyzing these decoders, we find that knowledge about the upstream channels is essential for good sink decoding.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939234]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1402</startPage>
			<endPage>1412</endPage>
			<fileSize>532</fileSize>
			<authors><![CDATA[Xiao, M.;Aulin, T.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Throughput and Delay Analysis of 802.11-Based Wireless Networks Using Smart and Directional Antennas]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939235]]></link>
			<description><![CDATA[This paper proposes a mathematical framework for comparing the performance of wireless networks based on the IEEE 802.11 standard, employing switched-beam, directional and adaptive antennas. The analysis adopts detailed models for the antenna system behavior and the propagation environment, taking into account multipath and interference. The purpose of this study is to determine the number of simultaneous communications that may be sustained by adopting advanced antenna systems, and to investigate, by analysis and simulation, the resulting performance improvements, in terms of throughput and packet delay. Both saturated and non-saturated traffic conditions are treated. Suitable 802.11 Medium Access Control (MAC) layer parameter settings, able to exploit smart and directional antenna capabilities for maximizing the throughput, are also discussed.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939235]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1413</startPage>
			<endPage>1423</endPage>
			<fileSize>459</fileSize>
			<authors><![CDATA[Babich, F.;Comisso, M.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Multiclass, Multistage, and Multilevel Fiber-Optic CDMA Signaling Techniques Based on Advanced Binary Optical Logic Gate Elements]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939236]]></link>
			<description><![CDATA[In this paper we introduce and propose novel signaling methods and receiver structures based on advanced binary optical logic gates for fiber-optic code division multiple access (FO-CDMA) systems using all-optical signal processing. In the proposed system the users of the network are categorized into multiple classes. Users of each class transmit at the same power level but different from the levels of the other classes¿ users. Using a combination of optical OR, AND and XNOR logic gates for the receiver structure we show that such a network not only takes the full advantages of all-optical signal processing but also demonstrates a considerable throughput efficiency when compared to ordinary FO-CDMA systems. The proposed receiver structure mitigates the effect of interfering users from the other classes by rejecting some specified power level combinations from the other classes. The depth of interference cancellation is a function of the corresponding number of power levels and the number of stages applied to the optical logic gates in use. In our analysis we choose the generalized form of optical orthogonal codes (OOC), i.e., OOCs with cross-correlation value greater than one, as the signature sequence. We begin by emphasizing on two-level systems, that is, when the users can select one out of two power levels for signal transmission. However, for multilevel FO-CDMA we obtain a closed-form relation for the upper bound on the probability of error.We will show that under the ideal case the increase in throughput resulting from the proposed multilevel system is proportional to the number of classes or power levels in use. Our analytical results are compared to the results of an extensive system simulation. The numerical closeness between, the analytical and system simulation, indicates the accuracy with which we have modeled mathematically our proposed signaling using advanced binary optical logic gates in FO-CDMA.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939236]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1424</startPage>
			<endPage>1432</endPage>
			<fileSize>604</fileSize>
			<authors><![CDATA[Ghaffari, B.M.;Salehi, J.A.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Asymptotic Critical Transmission Radii for Greedy Forward Routing in Wireless Ad Hoc Networks]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939237]]></link>
			<description><![CDATA[In wireless ad hoc networks, greedy forward routing is a localized geographic routing algorithm in which one node discards a packet if none of its neighbors is closer to the destination of the packet than itself, or otherwise forwards the packet to the neighbor closest to the destination. If all nodes have the same transmission radii, the critical transmission radius for greedy forward routing is the smallest transmission radius which ensures packets can be delivered by greedy forward routing through any source-destination pair. In this paper, we study asymptotic critical transmission radii of randomly deployed wireless ad hoc networks. Assume network nodes are represented by a Poisson point process of density n over a unit-area convex compact region whose boundary curvature is bounded. We show that the ratio of critical transmission radii to &#x0221A; ln n/¿n is asymptotically almost surely equal to &#x0221A; 1/ (2/3 ¿ &#x0221A;3/2&#x003C0;) &#x02248; 1.6.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939237]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1433</startPage>
			<endPage>1443</endPage>
			<fileSize>339</fileSize>
			<authors><![CDATA[Peng-Jun Wan;Chih-Wei Yi;Lixin Wang;Yao, F.;Xiaohua Jia;]]></authors>
		</item>
		<item>
			<title><![CDATA[Modelling and Analysis of Priority Queueing Systems with Multi-Class Self-Similar Network Traffic: A Novel and Efficient Queue-Decomposition Approach]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939238]]></link>
			<description><![CDATA[Traffic self-similarity has been discovered to be a ubiquitous phenomenon in communication networks and multimedia systems. Due to its fractal-like nature, performance modelling of self-similar traffic poses greater challenges and exhibits more complexity than that of traditional non-bursty traffic. As a result, most existing studies on analytical modelling of priority queueing systems with self-similar inputs have been restricted to a simplified scenario where only two traffic flows are taken into account. This study contributes to performance modelling of priority queueing systems by proposing a novel queue-decomposition approach, which offers several potential advantages and unique innovations. Specifically, we extend the well-known Empty Buffer Approximation (EBA) method to model priority queueing systems with multiple traffic flows and decompose the original priority queueing system into a group of single-server single-queue systems, which can make the challenging performance modelling problem tractable. We further develop an analytical model to investigate the queue length distributions of individual traffic flows. The validity and accuracy of the model demonstrated through extensive simulation experiments make it a practical and cost-effective evaluation tool for quantitatively evaluating the performance behavior of priority queueing systems with multi-class self-similar traffic under various working conditions.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939238]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1444</startPage>
			<endPage>1452</endPage>
			<fileSize>551</fileSize>
			<authors><![CDATA[Jin, X.;Min, G.;]]></authors>
		</item>
		<item>
			<title><![CDATA[On the Mutual Information Distribution of MIMO Rician Fading Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939239]]></link>
			<description><![CDATA[In a fading environment, the statistical distribution of the mutual information of a multiple-input multiple-output (MIMO) system depends on the joint distribution of the eigenvalues of a Wishart matrix, and is quite complex in general. We obtain here simple expressions for the distributions of the determinant and the trace of a Wishart matrix. Based on the obtained distributions, we derive some simple and tight bounds on the complementary cumulative distribution function (CCDF) of the mutual information of a MIMO system in Rician fading environments. The bounds obtained on the CCDF of mutual information provide further insights into the channel mutual information, and show the effects of the system parameters on the mutual information distribution explicitly. In addition, results for the Rayleigh channels are obtained as a special case.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939239]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1453</startPage>
			<endPage>1462</endPage>
			<fileSize>512</fileSize>
			<authors><![CDATA[Yonglan Zhu;Pooi-Yuen Kam;Yan Xin;]]></authors>
		</item>
		<item>
			<title><![CDATA[Design Criteria of Two-Hop Based Wireless Networks with Non-Regenerative Relays in Arbitrary Fading Channels]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939240]]></link>
			<description><![CDATA[In this paper we evaluate outage performances of multirelay amplify and forward (AF) transmission over fading channels. We focus on the uplink of a two-hop based network where N (with N &#x02A7E; 1) single antenna relay stations (RSs) serve as non-regenerative repeaters for the message transmitted by a single antenna source node (or mobile station MS). Performances are derived at high SNR for arbitrary fading distributions over each cooperative link. In Rayleigh fading the high price of cooperation in terms of signalling (e.g. during MS-to-RSs transmissions and control messages broadcasts) causes a significant loss in spectral efficiency. Instead, provided that the RSs can be strategically positioned to benefit from a channel with marginal diffusive fading component compared to Rayleigh, this paper shows that this loss in efficiency can be significantly alleviated depending on the particular propagation environment. Closed form conditions on the fading statistics for the relayed links are derived to guarantee that collaborative transmission performs as if the MS node would benefit from the same diversity and bandwidth efficiency provided by multi-antenna transmission. The proposed conditions are computed for arbitrary distributed fading for the relays-to-BS link and are specialized for Rice faded RSs-to-BS links.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939240]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1463</startPage>
			<endPage>1473</endPage>
			<fileSize>756</fileSize>
			<authors><![CDATA[Savazzi, S.;Spagnolini, U.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Performance Analysis of the IEEE 802.15.4a UWB System]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939241]]></link>
			<description><![CDATA[The recently approved IEEE 802.15.4a standard defines an ultra-wideband (UWB) based physical layer using concatenated coding with mixed binary phase-shift keying and binary pulse-position modulation (BPSK-BPPM) and directsequence spreading with time hopping. The concatenated code consists of an outer Reed-Solomon (RS) and an inner convolutional code, and the coding and modulation are combined such that both coherent and noncoherent receiver architectures are supported. In this paper, the error-rate performance of IEEE 802.15.4a compliant UWB radios is investigated. To this end, semi-analytical expressions for the bit-error rate (BER) and frame-error rate (FER) of the coded UWB system are derived. The presented framework is comprehensive in that (i) different methods for generating reliability information (i.e., decoding metrics), (ii) the effects of suboptimal multipath combining, and (iii) coherent and noncoherent reception methods are included. Furthermore, a particularly suited errors-and-erasures RS decoding scheme is devised. The evaluation of the error-rate expressions together with simulation results for realistic UWB channels show that (i) the error-rate approximations are tight over wide ranges of BER and FER, (ii) symbol-wise metrics are clearly advantageous over bit-wise metrics for decoding of the convolutional code, (iii) combining the 5 to 10 strongest multipath components approaches the performance of full combining within 1-2 dB for residential and 3-5 dB for outdoor UWB environments, and (iv) the simplicity of noncoherent detection comes at loss of more than 10 dB in signal-to-noise ratio compared to coherent detection.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939241]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1474</startPage>
			<endPage>1485</endPage>
			<fileSize>379</fileSize>
			<authors><![CDATA[Ahmadian, Z.;Lampe, L.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Near-Capacity Three-Stage Turbo Detection of Irregular Convolutional Coded Joint Sphere-Packing Modulation and Space-Time Coding]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939242]]></link>
			<description><![CDATA[Conventional two-stage turbo-detected schemes typically suffer from a Bit Error Rate (BER) floor, preventing them from achieving infinitesimally low BER values, especially, when the inner coding stage is of non-recursive nature. We circumvent this deficiency by proposing a three-stage turbo-detected Sphere Packing (SP) aided Space-Time Block Coding (STBC) STBC-SP scheme, where a rate-1 recursive inner precoder is employed to avoid having a BER floor. The convergence behaviour of this serially concatenated scheme is investigated with the aid of 3D Extrinsic Information Transfer (EXIT) Charts. Furthermore, the capacity of the STBC-SP scheme is determined and an algorithm is proposed for calculating a tighter upper bound on the maximum achievable bandwidth efficiency, based on the EXIT charts of the STBC-SP demapper. The proposed threestage turbo-detected scheme operates within about 1.0 dB of the capacity and within 0.5 dB of the maximum achievable bandwidth efficiency limit.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939242]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1486</startPage>
			<endPage>1495</endPage>
			<fileSize>364</fileSize>
			<authors><![CDATA[Alamri, O.;Wang, J.;Ng, S.X.;Yang, L.-L.;Hanzo, L.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Linear IIR Precoding for Non-Redundant Transmission over Minimum-Phase Channels in Wireline Multitone Systems]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939243]]></link>
			<description><![CDATA[Discrete multitone (DMT) systems need the use of a guard interval, known as cyclic prefix (CP), to avoid intersymbol interference (ISI) and interchannel interference (ICI). Unfortunately, this prefix produces a decrease in the achievable bandwidth efficiency. To overcome this problem, we present in this paper an IIR linear precoder that adds memory in the timedomain, avoiding the need of a guard time. It is shown that the received signal with this precoder and the received signal in a DMT system that uses CP are identical, so perfect reconstruction is possible in a noise-free situation. In addition, the behavior of this scheme in presence of noise is the same as in a DMT system with CP, allowing the use of bit and power loading algorithms. It is also proved that the only condition for the precoder stability is that the channel is minimum-phase. As an example, it is shown the good performance of this algorithm in an ADSL environment.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939243]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1496</startPage>
			<endPage>1504</endPage>
			<fileSize>437</fileSize>
			<authors><![CDATA[Simois, F.J.;Acha, J.I.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Bit-Interleaved Coded Multiple Beamforming with Imperfect CSIT]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939244]]></link>
			<description><![CDATA[This paper addresses the performance of bitinterleaved coded multiple beamforming (BICMB) [1], [2] with imperfect knowledge of beamforming vectors. Most studies for limited-rate channel state information at the transmitter (CSIT) assume that the precoding matrix has an invariance property under an arbitrary unitary transform. In BICMB, this property does not hold. On the other hand, the optimum precoder and detector for BICMB are invariant under a diagonal unitary transform. In order to design a limited-rate CSIT system for BICMB, we propose a new distortion measure optimum under this invariance. Based on this new distortion measure, we introduce a new set of centroids and employ the generalized Lloyd algorithm for codebook design. We provide simulation results demonstrating the performance improvement achieved with the proposed distortion measure and the codebook design for various receivers with linear detectors.We show that although these receivers have the same performance for perfect CSIT, their performance varies under imperfect CSIT.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939244]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1505</startPage>
			<endPage>1513</endPage>
			<fileSize>470</fileSize>
			<authors><![CDATA[Sengul, E.;Park, H.J.;Ayanoglu, E.;]]></authors>
		</item>
		<item>
			<title><![CDATA[A Simple Dual-Mode Limited Feedback Multiuser Downlink System]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939245]]></link>
			<description><![CDATA[Generally limited feedback systems that multiplex multiple user signals are noise power limited in the low signal-tonoise- ratio (SNR) regime and interference power limited in the high SNR regime. If the amount of feedback does not grow with SNR, then there is a sum rate ceiling that increasing the transmit power alone cannot surpass. This paper proposes a simple dual mode system where the base station serves either one user or as many users as the number of transmit antennas. The switching mechanism is smooth and is based on instantaneous system conditions. The mobile determines its preferred transmission mode by using a very simple signal-to-interference-and-noiseratio (SINR) threshold. Based on the mobiles¿ feedback, the base station chooses the method of signalling accordingly. With a finite number of feedback bits per mobile, it is shown that the proposed system achieves close to the maximum of the sum-rate for single user and multiuser modes. We identify the preferrable mode for an asymptotically large number of users and/or SNR. This proposed architecture is suitable for systems with moderate coherence time, a moderate to large number of users, and a moderate SNR that cannot afford complex processing at the base station or at the mobile.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939245]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1514</startPage>
			<endPage>1522</endPage>
			<fileSize>364</fileSize>
			<authors><![CDATA[Chun Kin Au-Yeung;Seung Young Park;Love, D.J.;]]></authors>
		</item>
		<item>
			<title><![CDATA[Mutual Information of Multipath Channels with Imperfect Channel Information]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939246]]></link>
			<description><![CDATA[Analysis of mutual information is important to wireless transmission over fading channels, and is usually done by assuming perfect channel state information (CSI) available at the receiver. In many practical applications, however, the CSI must be estimated by sending a limited number of pilot symbols and thus, can suffer from considerable inaccuracy. The influence of CSI inaccuracy on achievable mutual information, though analyzed in the past, is not well understood. The difficulty arises from the presence of a product term of signal and channel estimation error in the received signal model, and the lack of appropriate tools to determine its probability density function. This situation forces the adoption of a bounding technique in current literature by treating the product term either as a signal component or as a noise component. In this paper, we take a different methodology by accurately fitting the received signal with the multivariate Pearson¿s type-7 (MPT-7) distribution. The new results are simple in expression, very accurate as evidenced by simulation, and capable of directly revealing the dependence of the achievable mutual information on a particular channel estimator.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939246]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1523</startPage>
			<endPage>1531</endPage>
			<fileSize>347</fileSize>
			<authors><![CDATA[Song, S.H.;Zhang, Q.T.;]]></authors>
		</item>
		<item>
			<title><![CDATA[On High-Rate Full-Diversity 2 ÿ 2 Space-Time Codes with Low-Complexity Optimum Detection]]></title>
			<link><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939247]]></link>
			<description><![CDATA[The 2 ÿ 2 MIMO profiles included in Mobile WiMAX specifications are Alamouti¿s space-time code (STC) for transmit diversity and spatial multiplexing (SM). The former has full diversity and the latter has full rate, but neither of them has both of these desired features. An alternative 2ÿ2 STC, which is both full rate and full diversity, is the Golden code. It is the best known 2ÿ2 STC, but it has a high decoding complexity. Recently, the attention was turned to the decoder complexity, this issue was included in the STC design criteria, and different STCs were proposed. In this paper, we first present a full-rate full-diversity 2 ÿ 2 STC design leading to substantially lower complexity of the optimum detector compared to the Golden code with only a slight performance loss. We provide the general optimized form of this STC and show that this scheme achieves the diversitymultiplexing frontier for square QAM signal constellations. Then, we present a variant of the proposed STC, which provides a further decrease in the detection complexity with a rate reduction of 25% and show that this provides an interesting trade-off between the Alamouti scheme and SM.]]></description>
			<pubDate><![CDATA[May  2009]]></pubDate>
			<guid><![CDATA[http://ieeexplore.ieee.org/xpls/abs_all.jsp?isnumber=4939204&arnumber=4939247]]></guid>
			<volume>57</volume>
			<issue>5</issue>
			<startPage>1532</startPage>
			<endPage>1541</endPage>
			<fileSize>390</fileSize>
			<authors><![CDATA[Sezginer, S.;Sari, H.;Biglieri, E.;]]></authors>
		</item>
	</channel>
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