Brichet, F, Roberts, J, Simonian, A & Veitch, D 1996, 'Heavy traffic analysis of a storage model with long range dependent On/Off sources', Queueing Systems, vol. 23, no. 1-4, pp. 197-215.
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Guo, YJ, Paez, A, Sadeghzadeh, RA & Barton, SK 1996, 'A patch antenna for HIPERLAN', Wireless Personal Communications, vol. 3, no. 4, pp. 389-396.
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A patch antenna suited for indoor HIPERLAN is presented. The antenna operates in T M 02 mode and its radiation pattern is omnidirectional in azimuth and has a null in the normal direction. An experimental prototype has been designed and tested. A 6.1 % bandwidth of VSWR ≤ 2 and 4.2 dB antenna gain were measured at 5 GHz band. © 1996 Kluwer Academic Publishers.
Tellambura, C, Guo, YJ & Barton, SK 1996, 'Co-channel and self-interference analysis for indoor wireless channels', Wireless Personal Communications, vol. 3, no. 4, pp. 411-419.
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To achieve a user data rate of 20 Mbit/s in the high performance local area network (HIPERLAN) system operating in indoor environments, channel equalization must be used to mitigate the effects of multipath propagation. If, however, the indoor channel impulse response length is too long, then the multipath power outside of the equalisation capability of the equalizer acts as a form of self interference. Moreover, co-channel interference may also be present at the detector input. Considering these two effects as well as the rms delay spread, this paper derives analytical expressions for the probability of outage. © 1996 Kluwer Academic Publishers.
Tellambura, C, Guo, YJ & Barton, SK 1996, 'Equaliser Performance for HIPERLAN in indoor channels', Wireless Personal Communications, vol. 3, no. 4, pp. 397-410.
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In order to accomplish practical deployment modelling for system performance evaluation and comparison for possible modulation and equalisation schemes to be used in HIPERLAN, a wide band tapped delay line (WTDL) channel model has been adopted by ETSI to characterise the multipath fading in the indoor radio environment. Based on this statistical channel model, and using Monte Carlo method, this paper evaluates the average probability of error for linear and decision feedback equalisers as a function of signal-to-noise ratio. It also evaluates the matched filter bound for this channel model. The results show the optimum performance levels achievable via the use of any equaliser. © 1996 Kluwer Academic Publishers.
Alkussayer, HM, Guo, YJ & Barton, SK 1970, 'Low-cost multi-user receiver for synchronous CDMA systems', Conference Record / IEEE Global Telecommunications Conference, pp. 1588-1591.
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The effect of noise enhancement of the linear decorrelating detector (LDD) is investigated by studying a low complexity receiver for synchronous Code Division Multiple Access (CDMA) systems. Using Gold codes as the spreading sequences a general formula of the decorrelating matrix is obtained, which leads to a simplified receiver structure and explicit expression of the bit error ratio (BER). It is shown that even with multiple access interference (MAI) reduced, the BER of the system is still dependent on the bandwidth efficiency. For a given bandwidth, efficiency, the system performance improves when the processing gain is increased.
Alkussayer, HM, Zheng, FC, Guo, YJ & Barton, SK 1970, 'Time diversity decorrelator (TDD); a near-far resistant detector for asynchronous CDMA system', IEEE Vehicular Technology Conference, pp. 564-568.
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In this paper a near-far resistance detector for asynchronous Code-Division Multiple-Access (CDMA) systems operating in Additive White Gaussian Noise (AWGN) channels is presented. The multi-user interference caused by K users transmitting simultaneously, each with a specific signature sequence, is completely removed at the receiver. The complexity of this detector grows only linearly with the number of users, as compared to the optimum multi-user detector which requires exponential complexity in the number of users. A modified algorithm based on time diversity is described. It performs detection on a bit-by-bit basis and overcomes the complexity of using a sequence detector. The performance of this detector is shown to be superior to that of the conventional receiver.
Braun, RM, Horwitz, R & Kaplan, D 1970, 'Reform of the South African telecommunications sector - some ramifications thereof', IEEE AFRICON Conference, 1996 IEEE AFRICON / 4th AFRICON Conference in Africa - Electrical Energy Technology, Communication Systems, Human Resources, I E E E, STELLENBOSCH, SOUTH AFRICA, pp. 68-72.
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This paper describes the background to the present regulatory framework of the South African telecommunications sector. The paper considers the present infrastructure, its ownership and its capabilities. The paper then goes on to discuss the process followed in the creation of a new regulatory framework. It discusses the details of what is proposed, and the ramifications. The effect of technological advancement is put into the context of a new de-regulated market.
Cucchiara, R & Piccardi, M 1970, 'DARPA benchmark image processing on SIMD parallel machines', Proceedings of 1996 IEEE Second International Conference on Algorithms and Architectures for Parallel Processing, ICA/sup 3/PP '96, 1996 IEEE Second International Conference on Algorithms and Architectures for Parallel Processing, ICA/sup 3/PP '96, IEEE, SINGAPORE, SINGAPORE, pp. 171-178.
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Cucchiara, R & Piccardi, M 1970, 'Detection of luminosity profiles of elongated shapes', Proceedings of 3rd IEEE International Conference on Image Processing, 3rd IEEE International Conference on Image Processing, IEEE, LAUSANNE, SWITZERLAND, pp. 635-638.
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Cuthbert, J & Braun, RM 1970, 'Multi-h modulation indexes selection using the PBIL algorithm', Proceedings of IEEE. AFRICON '96, IEEE. AFRICON '96, IEEE, STELLENBOSCH, SOUTH AFRICA, pp. 1109-1114.
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Fuente, MP, Guo, YJ & Barton, SK 1970, 'New scheme for direct sequence spread spectrum radio LANs', IEEE International Symposium on Spread Spectrum Techniques & Applications, pp. 1320-1324.
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A new direct sequence spread spectrum scheme for ISM band Radio Local Area Networks using BPSK modulation and matched filter receivers is presented. It employs an optimized 22-chip sequence whose two 11-chip segments are alternately used as spreading sequences for adjacent symbols. Owing to the low cross-correlation between the two 11-chip segments, the inter-symbol interference caused by long delays in multipath channels is significantly reduced. In the paper, a receiver structure using the optimized sequence and time diversity is described and simulation results are given. Compared with the schemes using the short 11-chip Barker code and long M-sequences, the new scheme offers superior system performance.
Jordaan, GD, Du Plooy, CE & Braun, RM 1970, 'Clock recovery scheme for 7PRS signals', IEEE AFRICON Conference, pp. 397-401.
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Baseband PRS signals do not contain any spectral components at the symbol rate or submultiples thereof. For this reason difficulty is frequently experienced in synchronizing a PRS receiver with the data transmitter. This is a description of a novel synchronization scheme developed for such signals - using digital signal processing (DSP) techniques. A channel filter with a response derived from the raised cosine (RC) frequency response is used. This is followed by a limited amount of processing, resulting in a substantial signal at the required frequency.
Nel, EJ & Braun, RM 1970, 'Development of a directional coupler to be used on the two-wire sections of dial-up telephone lines', IEEE AFRICON Conference, 1996 IEEE AFRICON / 4th AFRICON Conference in Africa - Electrical Energy Technology, Communication Systems, Human Resources, I E E E, STELLENBOSCH, SOUTH AFRICA, pp. 570-575.
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This project aims to develop a directional coupler for use on dial-up telephone lines. The need for such a coupler originated with the acceptance of the CCITT's (International Telegraph and Telephone Consultative Committee) V.32 bis recommendation regarding the operation of high-speed modems. This standard allows modems to communicate on the telephone network both simultaneously as well as within the same frequency band. The modems involved use a mechanism called echo cancellation to overcome this problem (with echo cancellation the modem subtracts that which it transmits from the signal on the line to get the signal it wishes to receive). However, a third party surveying the (two-wire sections of the) line is unable to interpret the signals on the line as there appears to be only one garbled signal. This paper develops the theoretical basis necessary for a directional coupler that will separate this garbled signal into its constituent signals and thus enable interpretation of such signals by a third party.
Peng, M, Guo, YJ & Barton, SK 1970, 'One-shot linear decorrelating detector for asynchronous CDMA', Conference Record / IEEE Global Telecommunications Conference, pp. 1301-1305.
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A one-shot linear decorrelating detector(LDD) for the detection of asynchronous CDMA is presented. By treating every user as two independent users and using maximal ratio combining, a bit-by-bit detection is obtained. By applying a phase estimation algorithm on the output of the one-shot LDD, it is shown that the proposed detector can be used for the detection of asynchronous CDMA without the knowledge of carrier phase of any user. Simulation results show that the performance of the proposed detector approaches that of the optimum detector for single user transmission.
van de Groenendaal, JG & Braun, RM 1970, 'Novel low cost direct sequence spread spectrum synchroniser', Canadian Conference on Electrical and Computer Engineering, 1996 Canadian Conference on Electrical and Computer Engineering - Glimpse into the 21st-Century, I E E E, UNIV CALGARY, CALGARY, CANADA, pp. 36-39.
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This paper presents a novel spread spectrum synchroniser that may be simpler and more cost effective than other synchronisation system. Acquisition and tracking is achieved using one network, and the decision as to whether the system is in lock only occurs once the two sequences are aligned. No intermediate decision is required on the state of synchronisation. This feature of the synchroniser makes it cost effective and easy to implement. Although the synchroniser is not suitable for low signal-to-noise applications, it does highlight that it is possible to simplify the overall synchronisation process, while still having the benefits of spread spectrum.
