Multiple access performance in UWB systems using time hopping vs. direct sequence spreading

Somayazulu, V. Srinivasa

doi:10.1109/wcnc.2002.993322

Cited by 81 publications

(44 citation statements)

References 5 publications

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“…To avoid cross-frame collisions in MA system, total hop interval is limited to T f /2. Here, we adopt discrete uniform random TH and spreading sequence so as to evaluate the performances regardless of the choice of any particular code, as in [7], [8].…”

Section: Simulation Resultsmentioning

confidence: 99%

“…In this paper, we consider UWB ST systems employing different modulation and MA techniques, including TH MPPM [2], TH Binary Phase Shift Keying (BPSK) [1], and Direct Sequence (DS) BPSK [6]. The performance comparisons of TH and DS schemes for single antenna systems have been studied in [7], [8]. Here, we quantify the performance figures of UWB ST systems regardless of the specific coding scheme.…”

Section: Introductionmentioning

confidence: 99%

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On the performance evaluation of TH and DS UWB MIMO systems

Siriwongpairat

Olfat

Liu

2004

2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733)

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Section: Simulation Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the performance evaluation of TH and DS UWB MIMO systems

Siriwongpairat

Olfat

Liu

2004

2004 IEEE Wireless Communications and Networking Conference (IEEE Cat. No.04TH8733)

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“…Using different spread-spectrum technologies, the UWB transmissions can be achieved by several approaches [31], [32]. In [18], the concept of exclusive region was proposed for UWB-based ad hoc networks.…”

Section: Related Workmentioning

confidence: 99%

Multiclass Utility-Based Scheduling for UWB Networks

Liu

Cai

Shen

2008

IEEE Trans. Veh. Technol.

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Abstract-In this paper, the optimal scheduling problem for ultrawideband (UWB) networks is formulated as a utility maximization problem, considering heterogeneous traffic characteristics and the fairness constraint, which is an NP-hard problem. The utility function, defined as the user satisfaction level with respect to the allocated bandwidth, takes the link distance as the input parameter that may be noisy due to ranging errors. We solve the stochastic optimization problem by a metaheuristic, called the exclusive-region-based global search algorithm, that can avoid trapping into local optima with reasonable efficiency, complexity, and convergence speed. The concept of exclusive region for concurrent UWB communications is employed to improve algorithm efficiency. Extensive simulations demonstrate that, by appropriately scheduling concurrent transmissions, the total utilities of each traffic class can be significantly improved. In addition, the proposed scheduling algorithm can support heterogeneous applications and guarantee the intraclass and interclass fairness among competing flows.

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“…Actually, the idea of UWB MA systems dates back to the original proposal put forward by Scholtz [8], and with subsequent analyses in [9][10][11][12]. However, as in conventional CDMA systems, these proposed UWB MA systems also suffer from the multiple-access interference (MAI) problem, which severely restricts their performance and system capacity.…”

Section: Introductionmentioning

confidence: 99%

A complexity-performance-balanced multiuser detector based on artificial fish swarm algorithm for DS-UWB systems in the AWGN and multipath environments

Yin

Zong

Sun

et al. 2012

EURASIP J. Adv. Signal Process.

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In this article, an efficient multiuser detector based on the artificial fish swarm algorithm (AFSA-MUD) is proposed and investigated for direct-sequence ultrawideband systems under different channels: the additive white Gaussian noise channel and the IEEE 802.15.3a multipath channel. From the literature review, the issues that the computational complexity of classical optimum multiuser detection (OMD) rises exponentially with the number of users and the bit error rate (BER) performance of other sub-optimal multiuser detectors is not satisfactory, still need to be solved. This proposed method can make a good tradeoff between complexity and performance through the various behaviors of artificial fishes in the simplified Euclidean solution space, which is constructed by the solutions of some sub-optimal multiuser detectors. Here, these sub-optimal detectors are minimum mean square error detector, decorrelating detector, and successive interference cancellation detector. As a result of this novel scheme, the convergence speed of AFSA-MUD is greatly accelerated and the number of iterations is also significantly reduced. The experimental results demonstrate that the BER performance and the near-far effect resistance of this proposed algorithm are quite close to those of OMD, while its computational complexity is much lower than the traditional OMD. Moreover, as the number of active users increases, the BER performance of AFSA-MUD is almost the same as that of OMD.

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Multiple access performance in UWB systems using time hopping vs. direct sequence spreading

Cited by 81 publications

References 5 publications

On the performance evaluation of TH and DS UWB MIMO systems

On the performance evaluation of TH and DS UWB MIMO systems

Multiclass Utility-Based Scheduling for UWB Networks

A complexity-performance-balanced multiuser detector based on artificial fish swarm algorithm for DS-UWB systems in the AWGN and multipath environments

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