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Pursley, Michael B. Noneaker, Daniel Lee 2014-12-16T22:23:22Z 2014-12-16T22:23:22Z 10000-01-01 1993 1993 The performance of a direct-sequence spread-spectrum communication system is evaluated for selective fading channels and rake reception. Several issues are examined that influence the probability of error of the system, and closed-form expressions are obtained for the probability of error. The development of these expressions and the use of a general class of channel models permit the removal of some restrictions and approximations that have been employed previously in the analysis of rake receiver performance. It is demonstrated that the choice of the spreading sequence that is used for the direct-sequence waveform can have a significant effect on the probability of error. A good choice of the sequence produces a low probability of error over a range of channel delay spreads and Doppler spreads, and it is a good choice regardless of the number of taps of the rake receiver. The same sequence also provides superior performance for both coherent-combining and noncoherent-combining rake receivers. The effect of the chip rate on the probability of error for a direct-sequence spread-spectrum system is also considered. It is shown that, for both a correlation receiver and a multiple-tap rake receiver, a system employing a high chip rate provides better performance than a system employing a low chip rate for most typical land-mobile communication channels. The high-chip-rate system is also much less susceptible than the low-chip-rate system to degradation of performance due to the Doppler spreading of the channel. In addition, a rake receiver is shown to be necessary for the adequate performance of a low-chip-rate system, but it is of limited value for a high-chip-rate system. Made available in DSpace on 2014-12-16T22:23:22Z (GMT). No. of bitstreams: 1 9411733.pdf: 4202853 bytes, checksum: b164722f84ace845fb5e43e106ac5cb6 (MD5) Previous issue date: 1993 Embargo set by: Seth Robbins for item 72186 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs U of I Only 125 p. Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1993. http://hdl.handle.net/2142/72020 (UMI)AAI9411733 Engineering, Electronics and Electrical The Performance of Direct-Sequence Spread-Spectrum Communications With Selective Fading Channels and Rake Reception text Electrical Engineering Electrical Engineering University of Illinois at Urbana-Champaign Dissertation Ph.D.