摘要:

AbstractOptical packet switching is considered as a means to achieve high speed networking in future optical multi‐service networks, Optical switches of limited size are feasible with present‐day photonic technology, so solutions for the design and implementation of large switches are proposed here. They are based on a multistage architecture built using small switching modules with output queuing, organised according to a Clos topology. Many degrees of freedom are available for switch design and they are exploited to achieve performance optimisation in relation to packet loss. Simulation and analytical tools are developed to evaluate switch architecture performance. Results and application examples are given to show the feasibility of the multistage architecture for optical network

ISSN:1124-318X    

DOI:10.1002/ett.4460110502

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractPerformance measurements are a hot research topic for the design and control of high speed heterogeneous networks, such as the BISDN as well as the Internet. Our research in this field is concemed with a novel measurement system, with real‐time monitoring capabilities, whose working is based on sampling survey. The scenario used to test the accuracy of the proposed methodology is a “Passive QoS 2‐point measurement system” acting on an ATM network, which is fed with different kinds of traffic: synthetic traces (traditional as well as LRD models) and a trace of real ATM traffic captured on a transatlantic UK‐US link. Delay and loss characteristics, evaluated with the proposed sampling technique are compared against those foreseen by the sampling theory for several values of the sampling rate. The final result is a quantitative analysis that trades‐off accuracy and implementation costs of the measurement instruments and is a powerful control tool usable by networks managers to check the quality of service they are providing, to understand network internal dynamics and to design their monitor

ISSN:1124-318X    

DOI:10.1002/ett.4460110503

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractIn this paper the multiuser detection performance analysis‐ in synchronous direct sequence code division multiple access (DS‐CDMA) system using decorrelating and decision feedback (DFB) receivers, including single path Nakagami fading channel is presented. The lower bounds of the receivers bit error probability (BER) are derived, and the comparison of these receivers' performances to the conventional CDMA receiver is made. The analytical and numerical results show that the DFB receiver performs better in the presence of the high Nakagami fading chann

ISSN:1124-318X    

DOI:10.1002/ett.4460110504

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractCommunication over the discrete time memoryless Rayleigh fading channel is investigated. Codes achieving bit error rate (BER) lower than 10‐4at bit energy over the noise spectral density ratio (Eb/No) of 1 to 2dB from the channel capacity limit were found with coding rates of 0.05 to 0.36 bits per channel use. Similar codes with rates of up to 0.57 also performed reasonably close to the capacity limit. The codes are serial concatenation of turbo code and a modulation code such as Pulse Position Modulation (PPM). The receiver is based on joint iterative decoding of the turbo code and the modulation code. Information theoretic arguments are used to form guidelines for code design and to estimate performance of the iterative decode

ISSN:1124-318X    

DOI:10.1002/ett.4460110505

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractThe Kerr effect in an intensity modulated direct detection subcarrier multiplexed system with multiple optical carriers is investigated in this paper. An expression for inteference power spectrum is derived taking into consideration the laser phase noise and Kerr effect. The derivation is carried out first for the case of two optical carriers, and then generalised for the lightwave system withNoptical camers.

ISSN:1124-318X    

DOI:10.1002/ett.4460110506

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractIn this letter we present a time domain blind adaptive algorithm to jointly estimate amplitude, phase, and time delay of each user in a code division multiple access (CDMA) signal. It is based on the cyclostationary nature of the CDMA signal and it uses the estimates of normalized cyclic and conjugate cyclic autocorrelation functions of the received signal. Since the latter can be obtained as solution of a minimum mean square error optimization problem adaptive algorithms can be used to obtain an on line implementation of the procedure. Performances are evaluated through simulation.

ISSN:1124-318X    

DOI:10.1002/ett.4460110507

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractThe Multi Carrier Modulation (MCM) system with a multistage encoding/decoding scheme based on repetition and erasures‐correcting decoding of block codes applied for a Nakagami fading channel is considered. Bit Error Rate (BER) as a function of Signal‐to‐Noise Ratio (SNR) has been found to agree well with the simulated results. It is shown that for low SNR the proposed system has a lower BER than both the MCM with Forward Error Correction (FEC) and MCM with optimal diversity reception an

ISSN:1124-318X    

DOI:10.1002/ett.4460110508

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

摘要:

AbstractThis letter presents a real‐time lossless compression/decompression unit for disparity map information used in 3D teleconferencing systems. A lossless compression algorithm is used to compress the disparity map data in real‐time, resulting in a variable bit‐rate data stream that has to be transmitted through a constant bit‐rate channel. The system uses a controlled‐data‐loss method for data rate adaptation and for minimizing the loss of

ISSN:1124-318X    

DOI:10.1002/ett.4460110509

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

ISSN:1124-318X    

DOI:10.1002/ett.4460110511

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY

ISSN:1124-318X    

DOI:10.1002/ett.4460110501

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:2000

数据来源: WILEY