Abstract
This paper considers a multi-cell orthogonal frequency division multiple access (OFDMA) downlink system with several decode-and-forward (DF) relay stations (RSs) aiding the base station (BS) transmissions. The problem considered is the maximization of the system sum rate with a total power constraint in each cell. An iterative semi-distributed resource allocation (RA) algorithm is first proposed to optimize mode selection (decision whether relaying should be used or not and which relay), subcarrier assignment (MSSA), and power allocation (PA), alternatively. During the MSSA stage, the problem is decoupled into subproblems which can be solved distributively in linear time. During the PA stage, an algorithm based on single condensation and Lagrange duality (SCLD) is designed to optimize PA with the tentative MSSA results. The convergence of the SCLD-based RA algorithm is theoretically guaranteed and an local optimum is reached after convergence. To solve the formulated problem autonomously, a modified iterative water-filling (IWF) algorithm is further proposed. Specifically, each cell autonomously optimizes its own sum rate with the estimated power values of the received interferences from the other cells. An optimum algorithm is proposed to solve the local RA problem in each cell. Through numerical experiments, the convergence of the two proposed algorithms as well as their benefits compared with a centralized algorithm (CA) are illustrated.
Highlights
High data rate and ubiquitous coverage are strongly required in the next-generation wireless communication networks
RPA corresponds to the random power allocation
UPA corresponds to the uniform power allocation algorithm, and BPA corresponds to applying the optimal PA algorithm proposed in [16] when the cochannel interference (CCI) is always set to 0
Summary
High data rate and ubiquitous coverage are strongly required in the next-generation wireless communication networks. To address this issue, [14,15,16,17,18,19,20,21,22] have proposed and studied improved high spectrum efficiency (HSE) protocols which allow new symbols to be transmitted on the subcarriers unused by the relay during the second TS Note that all these papers consider RA in single-cell situations and model the cochannel interference (CCI) as additive background noise. For multicell OFDMA systems without DF relaying, several RA algorithms have been proposed in [29,30,31,32] These methods cannot be extended directly to solve RA problems jointly optimizing transmission mode selection, subcarrier assignment (MSSA), as well as power allocation (PA) in multi-cell OFDMA systems with opportunistic DF relaying.
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 callMore From: EURASIP Journal on Wireless Communications and Networking
Disclaimer: 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.
