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Communications Letters, IEEE

Issue 12 • Date Dec. 2002

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Displaying Results 1 - 16 of 16
  • Channel and capacity estimation errors

    Publication Year: 2002 , Page(s): 517 - 519
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (332 KB) |  | HTML iconHTML  

    Systems with multiple element transmitter and receiver arrays have been shown to achieve very high spectral efficiencies. The theoretically achievable Shannon capacity is a function of the channel between the transmitters and the receivers. On the simulation level, one assumes certain statistical characteristics for the channel, but on a practical level, the actual channel is measured. We show that the accuracy of the measurements affects the accuracy of the capacity estimation when using the Shannon formula. We study analytically how the channel estimation error appears in the capacity formula, and we derive mathematical expressions for the first- and second-order approximations of the error. We also present simulation results that show the effect of the system size, the measurement accuracy, the system signal-to-noise ratio and the nature of the channel itself on the accuracy of the estimation of the channel capacity. View full abstract»

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  • Symbol error probability of low-order orthogonal signalings in Rayleigh fading with general diversity combining

    Publication Year: 2002 , Page(s): 520 - 522
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (354 KB) |  | HTML iconHTML  

    New analytical expressions for the symbol error probability of 3-ary and 4-ary orthogonal signaling and 6-ary and 8-ary biorthogonal signaling with general diversity combining in Rayleigh fading are derived. View full abstract»

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  • Asymptotic performance of space-frequency codes over broadband channels

    Publication Year: 2002 , Page(s): 523 - 525
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    We show that when the number of receive antennas is large, the Euclidean distance among codewords dominates the performance of space-frequency codes, the same result as for space-time codes. Therefore, in the presence of a large number of receive antennas, space-frequency codes can be optimized by using the Euclidean-distance criterion valid for additive white Gaussian noise channels. Simulation results show that this conclusion is also valid when the number of antennas is small. View full abstract»

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  • Spectral density of random UWB signals

    Publication Year: 2002 , Page(s): 526 - 528
    Cited by:  Papers (19)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (292 KB) |  | HTML iconHTML  

    We derive the power spectral density of time-hopping (TH) spread-spectrum signals in the presence of random timing jitter. Detailed descriptions of different TH schemes, employing a random TH sequence, are given and spectral analysis of such TH signals in the presence of uniform timing jitter is carried out using a systematic and tractable technique. View full abstract»

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  • Orthogonal code hopping multiplexing

    Publication Year: 2002 , Page(s): 529 - 531
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB) |  | HTML iconHTML  

    An orthogonal code hopping multiplexing scheme is proposed as a statistical multiplexing scheme for an orthogonal downlink in order to accommodate more orthogonal downlink channels than orthogonal codewords for mobile stations, and its performance is evaluated. View full abstract»

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  • Single integral representations of certain integer powers of the Gaussian Q-function and their application

    Publication Year: 2002 , Page(s): 532 - 534
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (314 KB) |  | HTML iconHTML  

    Representations of the third and fourth powers of the Gaussian Q-function as a single integral with finite limits and an integrand that is Gaussian in the argument of the function are found. These representations are of the same form previously found for the first and second powers of the Q-function and, therefore, allow extended application of the moment-generating function approach for evaluating the performance of digital communication systems over generalized fading channels. View full abstract»

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  • A phase noise suppression algorithm for OFDM-based WLANs

    Publication Year: 2002 , Page(s): 535 - 537
    Cited by:  Papers (81)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB) |  | HTML iconHTML  

    Orthogonal frequency-division multiplexing (OFDM) has been specified by the IEEE 802.11a standard as the transmission technique for high-rate wireless local area networks (WLANs). The performance of an OFDM system, however, is heavily degraded by random Wiener phase noise, which causes both common phase error (CPE) and inter-carrier interference (ICI). To mitigate this problem, a new phase noise suppression (PNS) algorithm is proposed to efficiently eliminate the effect of phase noise on OFDM-based WLANs. Numerical results are presented to illustrate the effectiveness of the proposed algorithm. View full abstract»

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  • Average block error probability of multicell CDMA packet networks with fast power control under multipath fading

    Publication Year: 2002 , Page(s): 538 - 540
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (329 KB) |  | HTML iconHTML  

    We derive the average block error probability of multicell code-division multiple access (CDMA) packet networks with fast power control under multipath fading. Unlike many previous works, we consider that users are connected to a base station on a minimum attenuation basis. An analytical approach for the calculation of the intracell and intercell statistics is presented. By making use of these expressions, the mean block error probability is analyzed as a function of the number of resolvable paths and the number of base stations to which mobiles can connect. View full abstract»

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  • Performance analysis of optimum combining for dual-antenna diversity with multiple interferers in a Rayleigh fading channel

    Publication Year: 2002 , Page(s): 541 - 543
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (294 KB) |  | HTML iconHTML  

    We study the performance analysis of optimum combiner for M-ary phase-shift keying (MPSK) with multiple interferers in a flat Rayleigh fading channel. The first-order approximation is considered for the dual-antenna diversity reception. We derive the analytical solutions for the ordered mean eigenvalues of interference-plus-noise covariance matrix and a simple closed-form expression for the average symbol error rate of MPSK in the case of multiple cochannel interferers. View full abstract»

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  • Performance analysis for multistage interference cancellers in asynchronous DS-CDMA systems

    Publication Year: 2002 , Page(s): 544 - 546
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (371 KB) |  | HTML iconHTML  

    The authors propose an accurate analytical method for an asynchronous direct-sequence code-division multiple-access system using a multistage interference cancellation technique. In this analysis, the RAKE receiver is considered over uplink fading channels. Monte Carlo simulations show that the proposed analysis agrees more closely with simulation results than previous analyzes. View full abstract»

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  • Data-aided approach to I/Q mismatch and DC offset compensation in communication receivers

    Publication Year: 2002 , Page(s): 547 - 549
    Cited by:  Papers (34)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (314 KB) |  | HTML iconHTML  

    A digital signal processing technique for compensating both the I/Q mismatch and the DC offset in communication receivers is derived with an emphasis on direct-conversion architectures. The I/Q mismatch and DC offset are estimated in a least-squares sense using a training sequence. Also, a group of training sequences that minimizes the mean square error of the estimate is determined. The advantages of the proposed technique are demonstrated through computer simulation. View full abstract»

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  • Long-range dependence does not necessarily imply non-exponential tails

    Publication Year: 2002 , Page(s): 550 - 552
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (277 KB) |  | HTML iconHTML  

    We exhibit a buffer model with a provably long-range dependent input source but whose corresponding measure of buffer occupancy is exponentially distributed (and thus has exponential tails). This example invalidates the perception which has emerged in the literature on traffic engineering, that long-range dependencies necessarily induce nonexponential tails for the buffer asymptotics. View full abstract»

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  • URL formalization: an efficient technique to speedup content-aware switching

    Publication Year: 2002 , Page(s): 553 - 555
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (167 KB) |  | HTML iconHTML  

    We devise a data structure termed URL table to hold content-related information for making content-aware routing decisions. We also propose a novel idea termed "URL formalization", which provide a scalable solution to speedup the content-aware request routing. The performance result shows that our approaches can intelligently route Web requests at very high speed. View full abstract»

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  • List of reviewers

    Publication Year: 2002 , Page(s): 556 - 559
    Save to Project icon | Request Permissions | PDF file iconPDF (150 KB)  
    Freely Available from IEEE
  • Author index

    Publication Year: 2002 , Page(s): 560 - 565
    Save to Project icon | Request Permissions | PDF file iconPDF (216 KB)  
    Freely Available from IEEE
  • Subject index

    Publication Year: 2002 , Page(s): 565 - 579
    Save to Project icon | Request Permissions | PDF file iconPDF (276 KB)  
    Freely Available from IEEE

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IEEE Communications Letters  is aimed at satisfying the need for rapid dissemination of information, offering a vehicle for authors to expose their results to be used in future developments. This ensures early recognition of work. 

 

 

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Meet Our Editors

Editor-in-Chief
George K. Karagiannidis
Aristotle University of Thessaloniki
Greece