Fundamentals of the Simplex Communication Channel With Retransmissions
dc.contributor.author | Davidson, Boris | en |
dc.contributor.committeechair | Bostian, Charles W. | en |
dc.contributor.committeemember | Davis, Nathaniel J. IV | en |
dc.contributor.committeemember | Midkiff, Scott F. | en |
dc.contributor.committeemember | Stutzman, Warren L. | en |
dc.contributor.committeemember | Kohler, Werner E. | en |
dc.contributor.department | Electrical and Computer Engineering | en |
dc.date.accessioned | 2014-03-14T20:21:49Z | en |
dc.date.adate | 1997-04-14 | en |
dc.date.available | 2014-03-14T20:21:49Z | en |
dc.date.issued | 1997-04-14 | en |
dc.date.rdate | 1998-04-14 | en |
dc.date.sdate | 1998-07-25 | en |
dc.description.abstract | The need for multiple access strategies arises whenever a number of users have to share a communication resource, since it is usually either cost prohibitive or impractical to dedicate a communication channel to a particular user. A need for such algorithms arises in many instances, particularly in applications utilizing wireless systems where all users access a common channel or medium. Such random access techniques as ALOHA and slotted ALOHA have been successfully implemented in a number of wireless applications. One of the major drawbacks of these algorithms is the necessity of a return path from the central station to each system user, which makes their use both inefficient and expensive for applications where one-way communication would suffice. For such applications, a need remained for a random access algorithm which can maximize the probability of successful message transmission in a one-way communication environment. A random access technique that addresses the above-mentioned need is developed. With this technique, each user sends an original message of predetermined length to a central receiver. The user then retransmits the message a specified number of times in a predetermined interval reserved for the retransmission process. The time interval between each successive retransmission of a given message is random. Assuming total annihilation of all colliding messages, the expression for the probability of successful transmission of a given message in terms of the major channel parameters is theoretically formulated. This technique offers a significant improvement, compared to a single transmission, in ensuring that a message is successfully received. The actual message collision dynamics in this system are experimentally studied using two different types of direct-sequence spread spectrum receivers, one employing a sliding correlator and the other using a matched filter. The spreading code in such systems offers extra protection for messages against possible interferers. The results indicate that it is often possible to properly receive a given message in the presence of co-channel interferers, thus significantly improving the overall system performance. These results are subsequently incorporated with the propagation data for several different types of microcells to arrive at a more precise theory of the link. | en |
dc.description.degree | Ph. D. | en |
dc.identifier.other | etd-332122139711101 | en |
dc.identifier.sourceurl | http://scholar.lib.vt.edu/theses/available/etd-332122139711101/ | en |
dc.identifier.uri | http://hdl.handle.net/10919/30471 | en |
dc.publisher | Virginia Tech | en |
dc.relation.haspart | dissertation.PDF | en |
dc.rights | In Copyright | en |
dc.rights.uri | http://rightsstatements.org/vocab/InC/1.0/ | en |
dc.subject | direct-sequence spread spectrum | en |
dc.subject | simplex channel | en |
dc.subject | message collisions | en |
dc.subject | multiple access | en |
dc.title | Fundamentals of the Simplex Communication Channel With Retransmissions | en |
dc.type | Dissertation | en |
thesis.degree.discipline | Electrical and Computer Engineering | en |
thesis.degree.grantor | Virginia Polytechnic Institute and State University | en |
thesis.degree.level | doctoral | en |
thesis.degree.name | Ph. D. | en |
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