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# IEEE Transactions on Communications

## Filter Results

Displaying Results 1 - 25 of 30

Publication Year: 2004, Page(s):c1 - c4
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• ### IEEE Transactions on Communications publication information

Publication Year: 2004, Page(s): c2
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• ### Generalized selection combining based on the log-likelihood ratio

Publication Year: 2004, Page(s):521 - 524
Cited by:  Papers (18)
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We propose a generalized selection combining (GSC) scheme for binary signaling in which a subset of diversity branches providing the largest magnitude of log-likelihood ratio (LLR) are selected and combined. It is shown that the bit-error probability with maximum ratio combining (MRC) or square-law combining of L branches is identical to that with LLR-based GSC of L/2 branches. We also propose a s... View full abstract»

• ### Mitigating error propagation in decision-feedback equalization for multiuser CDMA

Publication Year: 2004, Page(s):525 - 529
Cited by:  Papers (7)
| | PDF (272 KB) | HTML

This letter presents a robust decision-feedback equalization design that mitigates the error-propagation problem for multiuser direct-sequence code-division multiple-access systems under multipath fading. Explicit constraints for signal energy preservation are imposed on the filter weight vector to monitor and maintain the quality of the hard decisions in the nonlinear feedback loop. Such a measur... View full abstract»

• ### Design of nonuniformly spaced tapped-delay-line equalizers for sparse multipath channels

Publication Year: 2004, Page(s):530 - 535
Cited by:  Papers (22)  |  Patents (3)
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Analytical expressions that explicitly indicate the tap values and tap positions of infinite-length, T-spaced tapped-delay-line (TDL) equalizers for sparse multipath channels are derived. Simple design rules for allocating taps to finite-length, minimum mean-square error, nonuniformly spaced TDL equalizers (NU-Es) are formulated based on the derived results. The design-rule-based methodology demon... View full abstract»

• ### On the error probability of binary and M-ary signals in Nakagami-m fading channels

Publication Year: 2004, Page(s):536 - 539
Cited by:  Papers (66)
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In this letter, we present new closed-form formulas for the exact average symbol-error rate (SER) of binary and M-ary signals over Nakagami-m fading channels with arbitrary fading index m. Using the well-known moment generating function-based analysis approach, we express the average SER in terms of the higher transcendental functions such as the Gauss hypergeometric function, Appell hypergeometri... View full abstract»

• ### Speed and accuracy comparison of techniques for multiuser detection in synchronous CDMA

Publication Year: 2004, Page(s):540 - 545
Cited by:  Papers (25)
| | PDF (304 KB) | HTML

In this letter, we compare the complexity and efficiency of several methods used for multiuser detection in a synchronous code-division multiple-access system. Various methods are discussed, including decision-feedback (DF) detection, group decision-feedback (GDF) detection, coordinate descent, quadratic programming with constraints, space-alternating generalized EM (SAGE) detection, Tabu search, ... View full abstract»

• ### The impact of antenna diversity in packet data systems with scheduling

Publication Year: 2004, Page(s):546 - 549
Cited by:  Papers (9)
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It has been observed through simulations of some specific scheduling algorithms that multiuser diversity gains in packet data systems with channel-aware scheduling can be reduced in the presence of any form of link diversity, such as transmit antenna diversity or wideband multipath diversity. We establish that asymptotically, in the limit of large number of transmit antennas and users, the maximum... View full abstract»

• ### A simple expression for the optimization of spread-spectrum code acquisition detectors operating in the presence of carrier-frequency offset

Publication Year: 2004, Page(s):550 - 552
Cited by:  Papers (10)  |  Patents (1)
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In this letter, we present a simple expression for the optimization of the threshold detection performance for direct-sequence spread-spectrum code acquisition in the presence of carrier-frequency offset. The proposed scheme divides the total integration time into subintervals, and the results of the coherent integrations performed over these subintervals are noncoherently combined prior to detect... View full abstract»

• ### Transmission properties of conjugate-root pulses

Publication Year: 2004, Page(s):553 - 558
Cited by:  Papers (15)  |  Patents (1)
| | PDF (776 KB) | HTML

A family of pulses has recently been reported by Xia that are intersymbol interference-free with and without matched filtering. Reportedly, such pulses are important for systems where both matched filter and unmatched receivers are used. The transmission characteristics of these pulses are compared to the more commonly used raised-cosine pulse for three different receiver scenarios. View full abstract»

• ### A study of CDPD forward channel performance with coherent and differential detection

Publication Year: 2004, Page(s):559 - 563
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The media access control (MAC)-layer performance of the cellular digital packet data (CDPD) forward channel is studied and a new technique to improve the performance is proposed. The study is based on a computer simulation model wherein a CDPD base station continuously transmits a sequence of packets to a CDPD mobile station. We consider a Rayleigh fading channel and demonstrate how the performanc... View full abstract»

• ### Design of efficiently encodable moderate-length high-rate irregular LDPC codes

Publication Year: 2004, Page(s):564 - 571
Cited by:  Papers (190)  |  Patents (10)
| | PDF (344 KB) | HTML

This paper presents a new class of irregular low-density parity-check (LDPC) codes of moderate length (103≤n≤104) and high rate (R≥3/4). Codes in this class admit low-complexity encoding and have lower error-rate floors than other irregular LDPC code-design approaches. It is also shown that this class of LDPC codes is equivalent to a class of systematic serial turbo ... View full abstract»

• ### Robust OFDM receivers for dispersive time-varying channels: equalization and channel acquisition

Publication Year: 2004, Page(s):572 - 583
Cited by:  Papers (110)  |  Patents (13)
| | PDF (456 KB) | HTML

In orthogonal frequency-division multiplexing, time variations of a multipath channel lead to a loss of orthogonality between the subcarriers, and thereby limit the achievable throughput. This paper proposes a general framework for a controlled removal of intercarrier interference (ICI) and channel acquisition. The core idea behind our method is to use a finite power series expansion for the time-... View full abstract»

• ### A general SER formula for an OFDM system with MDPSK in frequency domain over Rayleigh fading channels

Publication Year: 2004, Page(s):584 - 594
Cited by:  Papers (15)
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A closed-form formula for symbol-error rate (SER) of an orthogonal frequency-division multiplexing (OFDM) system with M-ary differential phase-shift keying (MDPSK) in frequency domain over Rayleigh fading channels is obtained. It is found that, by MDPSK in frequency domain, identical SERs can be achieved on all subcarriers. However, both time and frequency dispersion in the channel will introduce ... View full abstract»

• ### Pilot-assisted channel estimation for the downlink of the UMTS-TDD component

Publication Year: 2004, Page(s):595 - 604
Cited by:  Papers (2)
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The time-division duplex (TDD) component of the universal mobile telecommunications system (UMTS) employs synchronous code-division multiple-access techniques with orthogonal spreading codes to provide protection against cochannel interference. In the presence of multipath propagation, however, the code orthogonality is lost and multiaccess interference is generated at the receiver. In such condit... View full abstract»

• ### Reliable adaptive modulation aided by observations of another fading channel

Publication Year: 2004, Page(s):605 - 611
Cited by:  Papers (18)  |  Patents (1)
| | PDF (288 KB) | HTML

Adaptive transmission techniques, such as adaptive modulation and coding, adaptive power control, adaptive transmitter antenna diversity, etc., generally require precise channel estimation and feedback of channel state information (CSI). For fast vehicle speeds, reliable adaptive transmission also requires long-range prediction of future CSI, since the channel conditions are rapidly time variant. ... View full abstract»

• ### Subspace-based active user identification for a collision-free slotted ad hoc network

Publication Year: 2004, Page(s):612 - 621
Cited by:  Papers (23)
| | PDF (376 KB) | HTML

We propose a novel spreading code scheme, transmitter-receiver-based code, for wireless ad hoc networks. The design facilitates collision resolution using multiuser detection at each node, and is more bandwidth efficient than creating orthogonal channels in time or frequency. A subspace-based receiver structure is introduced, which identifies users of interest, or "active" users, with minimal prio... View full abstract»

• ### Constant modulus and reduced PAPR block differential encoding for frequency-selective channels

Publication Year: 2004, Page(s):622 - 631
Cited by:  Papers (9)
| | PDF (352 KB) | HTML

Frequency-selective channels can be converted to a set of flat-fading subchannels by employing orthogonal frequency-division multiplexing (OFDM). Conventional differential encoding on each subchannel, however, suffers from loss of multipath diversity, and a very high peak-to-average power ratio (PAPR), which causes undesirable nonlinear effects. To mitigate these effects, we design a block differe... View full abstract»

• ### Fast optimal and suboptimal any-time algorithms for CDMA multiuser detection based on branch and bound

Publication Year: 2004, Page(s):632 - 642
Cited by:  Papers (31)
| | PDF (344 KB) | HTML

A fast optimal algorithm based on the branch-and-bound (BBD) method is proposed for the joint detection of binary symbols of K users in a synchronous code-division multiple-access channel with Gaussian noise. Relationships between the proposed algorithms (depth-first BBD and fast BBD) and both the decorrelating decision-feedback (DF) detector and sphere-decoding algorithm are clearly drawn. It tur... View full abstract»

• ### Trellis-coded multiple-pulse-position modulation for wireless infrared communications

Publication Year: 2004, Page(s):643 - 651
Cited by:  Papers (30)
| | PDF (480 KB) | HTML

We present new trellis codes based on multiple-pulse-position modulation (MPPM) for wireless infrared communication. We assume that the receiver uses maximum-likelihood sequence detection to mitigate the effects of channel dispersion, which we model using a first-order lowpass filter. Compared to trellis codes based on PPM, the new codes are less sensitive to multipath dispersion and offer better ... View full abstract»

• ### Multiuser detections for optical CDMA networks based on expectation-maximization algorithm

Publication Year: 2004, Page(s):652 - 660
Cited by:  Papers (15)
| | PDF (320 KB) | HTML

In this paper, we introduce new unblind and blind multiuser detectors for an optical code-division multiple-access system. The detectors have two soft and hard stages. In the soft stage, a soft estimation of the interference is obtained by solving an unconstrained maximum-likelihood problem via the iterative expectation-maximization (EM) algorithm. Then, the hard stage detects the user information... View full abstract»

• ### Embedding carrier phase recovery into iterative decoding of turbo-coded linear modulations

Publication Year: 2004, Page(s):661 - 669
Cited by:  Papers (95)  |  Patents (6)
| | PDF (632 KB) | HTML

In this paper, we introduce a low-complexity carrier phase estimation algorithm to be integrated into the data decoder of a turbo-coded modem employing a linear modulation. The estimator is based on a pseudo-maximum-likelihood approach and makes iterative use of soft decisions provided by the soft-in/soft-out decoders within the overall turbo-decoding scheme. In doing so, iterative decoding and ca... View full abstract»

• ### Design of low-density parity-check codes for modulation and detection

Publication Year: 2004, Page(s):670 - 678
Cited by:  Papers (619)  |  Patents (14)
| | PDF (360 KB) | HTML

A coding and modulation technique is studied where the coded bits of an irregular low-density parity-check (LDPC) code are passed directly to a modulator. At the receiver, the variable nodes of the LDPC decoder graph are connected to detector nodes, and iterative decoding is accomplished by viewing the variable and detector nodes as one decoder. The code is optimized by performing a curve fitting ... View full abstract»

• ### Performance of Multicarrier CDMA With Successive Interference Cancellation in a Multipath Fading Channel

Publication Year: 2004, Page(s): 679
| | PDF (35 KB)

Performance of Multicarrier CDMA With Successive Interference Cancellation in a Multipath Fading Channel A high-capacity, low-complexity, and robust system design for a successive interference cancellation (SIC) system is developed and analyzed. Multicarrier code-division multiple access (MC-CDMA) is used to suppress multipath and to overcome the multipath channel estimation problem in single-carr... View full abstract»

• ### Blind and Semiblind Detections of OFDM Signals in Fading Channels

Publication Year: 2004, Page(s): 679
| | PDF (35 KB)

This paper considers the problem of blind joint channel estimation and data detection for orthogonal frequency-division multiplexing (OFDM) systems in a fading environment. Employing a regression model for a time-varying channel, we convert the problem into one where finding the data sequence$bf x$whose associated least-squares (LS) channel estimate$bf z(bf x)$is closest to t... View full abstract»

## Aims & Scope

IEEE Transactions on Communications focuses on all telecommunications including telephone, telegraphy, facsimile, and point-to-point television by electromagnetic propagation.

Full Aims & Scope

## Meet Our Editors

Editor-in-Chief
Naofal Al-Dhahir
University of Texas at Dallas