Abstract
Methods for providing good spectral efficiency, without disadvantaging the delivered quality of service (QoS), in time-varying fading channels are presented. The key idea is to allocate system resources according to the encountered channel. Two approaches are examined: variable-size burst construction, and adaptive modulation. The first approach adapts the burst size according to the channel rate of change. In doing so, the available training symbols are efficiently utilized. The second adaptation approach tracks the operating channel quality, so that the most efficient modulation mode can be invoked while guaranteeing a target QoS. It is shown that these two methods can be effectively combined in a common framework for improving system efficiency, while guaranteeing good QoS. The proposed framework is especially applicable to multistate channels, in which at least one state can be considered sufficiently slowly varying. For such environments, the obtained simulation results demonstrate improved system performance and spectral efficiency.
Highlights
Achieving high spectral efficiency is an important goal in communication
It is important that the quality of service (QoS), quantified by the bit error rate (BER), will not deteriorate as a result of this goal
Designate the choice of available modulation modes by Vq, q = 1, . . . , Q, where Q is the total number of available modulation modes; V1 is the constellation with the least number of points; and VQ the highest
Summary
Achieving high spectral efficiency is an important goal in communication. it is important that the quality of service (QoS), quantified by the bit error rate (BER), will not deteriorate as a result of this goal. As will become evident in the remainder of the paper, the overall conclusion of this work is the following: if the underlying time-varying channel can be modeled as multistate, where at least one state is slowly varying, reliable communication is still possible using conventional burst-byburst techniques when coupled with a variable-size burst approach. By combining variable-size burst construction with basis-expansion modeling (BEM) of the channel [6, 7], the transmission efficiency can be improved. In this case, the system complexity is increased due to more complicated estimation and equalization procedures.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
