Joint Power and Constellation Size Adaptation for Mobile Multicast Employing MQAM Over Wireless Fading Channels

We consider the problem of joint power allocation (JPA) in a coordinated multi-point (CoMP) joint diversity transmission (JDT) network with a total coordination point power (TCPP) constraint, aimed at maximizing the ergodic cooperative capacity (ECC) in Rayleigh fading channels. In this paper, we first extend the JPA problem in the coordinated two-point (Co2P) JDT networkto the case of a non-unity TCPP constraint. Furthermore, we introduce more accurate log-quadratic approximated (LQA) expressions to obtain the coordinated transmission point (CTP) powers. Next, we extend our study to a coordinated three-point (Co3P) JDT network. Given the mean branch gain-to-noise ratios, we first obtain a log-linear approximated (LLA) expression for obtaining the optimum power of the third CTP (i.e., the worst quality-providing CTP). After obtaining the third-CTP power, we obtain the CTP powers of two better quality-providing CTPs by invoking the LLA CTP power expressions for Co2P JDT power allocation, under the remaining power given by the TCPP minus the third-CTP power. The numerical results demonstrate that the LQA and LLA CTP power expressions for Co2P JDT and the LLA CTP power expressions for Co3P JDT are very efficient in terms of the simplicity for JPA and CoMP set selection, as well as the resulting ECC.

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Resource Allocation for Wireless Networks with Energy Harvesting Constraints Over Fading Channels

Journal of Science and Technology Issue on Information and Communications Technology ◽

10.31130/jst.2016.20 ◽

2016 ◽

Vol 2 (1) ◽

pp. 9

Author(s):

Mohammed Baljon ◽

Lian Zhao

Keyword(s):

Resource Allocation ◽

Energy Harvesting ◽

Power Allocation ◽

Fading Channels ◽

Communication System ◽

Research Work ◽

Throughput Maximization ◽

Maximization Problem ◽

Joint Power ◽

Delay Tolerant

This research work considers the utilize of energy harvesters, instead of conventional time-invariant energy sources, in wireless communication. For the purpose of exposition, we study the traditional two-hop communication system for delay limited (DL) and delay tolerant (DT) relaying networks over fading channels, in which the source node transmits with power drawn from energy harvesting (EH) sources and the relay transmits with conventional non-EH sources. We address the throughput maximization problem for the proposed system model for DL and DT cases. We find that the optimal power allocation algorithm for the single-hop communication system with EH constraints, namely, recursive geometric water-filling(RGWF), can be utilized as a guideline for the design of the two-hop system. We first introduce RGWF algorithm and we show the advantages of the geometric approach in eliminating the complexity of the Karush-Kuhn-Tucker (KKT) condition as well as providing a closed-form and exact solutions to the proposed problem. Based on the RGWF algorithm, we propose offline joint power allocation and transmission time scheduling schemes for DL relaying network and DT relaying network. We also propose efficient online resource allocation schemes for both relays’ cases. The performance of the proposed schemes is evaluated via simulation and the results demonstrate that a network with delay tolerant ability provides better performance in term of throughput.

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