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Tradeoff between Energy-Efficiency and Spectral-Efficiency by Cooperative Rate Splitting
Yang, Chungang,Yue, Jian,Sheng, Min,Li, Jiandong The Korea Institute of Information and Commucation 2014 Journal of communications and networks Vol.16 No.2
The trend of an increasing demand for a high-quality user experience, coupled with a shortage of radio resources, has necessitated more advanced wireless techniques to cooperatively achieve the required quality-of-experience enhancement. In this study, we investigate the critical problem of rate splitting in heterogeneous cellular networks, where concurrent transmission, for instance, the coordinated multipoint transmission and reception of LTE-A systems, shows promise for improvement of network-wide capacity and the user experience. Unlike most current studies, which only deal with spectral efficiency enhancement, we implement an optimal rate splitting strategy to improve both spectral efficiency and energy efficiency by exploring and exploiting cooperation diversity. First, we introduce the motivation for our proposed algorithm, and then employ the typical cooperative bargaining game to formulate the problem. Next, we derive the best response function by analyzing the dual problem of the defined primal problem. The existence and uniqueness of the proposed cooperative bargaining equilibrium are proved, and more importantly, a distributed algorithm is designed to approach the optimal unique solution under mild conditions. Finally, numerical results show a performance improvement for our proposed distributed cooperative rate splitting algorithm.
Lin Yu,Wenjia Sheng,Dicheng Yang,Jiandong Ding 한국고분자학회 2013 Macromolecular Research Vol.21 No.2
Thermogelling block copolymers composed of polyester and polyether are faced with a dilemma of achieving powder form in order to easily handle the samples in the bulk state and avoid unexpected ahead-of-time gelling of the corresponding polymer aqueous solution below the thermogelling temperature due to the spontaneous crystallization of some polymer segments in water. In order to resolve this dilemma, we synthesized amphiphilic poly(ε-caprolactone-co-glycolide)-poly(ethylene glycol)-poly(ε-caprolactone-co-glycolide) (PCGA-PEG-PCGA) triblock copolymers with a series of ratios regarding caprolactone (CL) and glycolide (GA). The different polymer morphologies from powder to sticky paste were obatined by altering the ratios to adjust the ability of crytallization for the PCGA blocks. All of the copolymers reported in this paper were able to dissolve in water, and their aqueous solutions underwent a sol-gel transition upon heating. The polymer with an appropriate CL/GA ratio not only exhibited the powder form in the bulk state, but also achieved the sol stability in water. The triblock copolymers formed micelles in water and the micellar aggregation occurred with increasing temperature, resulting in physical gelation upon the percolation of micelles. The injectability and gellability of the copolymer-water systems were confirmed both in vitro and in vivo. Consequently, this study provides a promising injectable biomaterial, and also affords a new successful case of the molecular design of functional polymers, based upon common monomers.
Tradeoff between Energy-Efficiency and Spectral-Efficiency by Cooperative Rate Splitting
Chungang Yang,Jian Yue,Min Sheng,Jiandong Li 한국통신학회 2014 Journal of communications and networks Vol.16 No.2
The trend of an increasing demand for a high-quality userexperience, coupled with a shortage of radio resources, has necessitatedmore advanced wireless techniques to cooperatively achievethe required quality-of-experience enhancement. In this study, weinvestigate the critical problem of rate splitting in heterogeneouscellular networks, where concurrent transmission, for instance, thecoordinated multipoint transmission and reception of LTE-A systems,shows promise for improvement of network-wide capacityand the user experience. Unlike most current studies, which onlydeal with spectral efficiency enhancement, we implement an optimalrate splitting strategy to improve both spectral efficiency andenergy efficiency by exploring and exploiting cooperation diversity. First, we introduce the motivation for our proposed algorithm, andthen employ the typical cooperative bargaining game to formulatethe problem. Next, we derive the best response function byanalyzing the dual problem of the defined primal problem. Theexistence and uniqueness of the proposed cooperative bargainingequilibrium are proved, and more importantly, a distributed algorithmis designed to approach the optimal unique solution undermild conditions. Finally, numerical results show a performance improvementfor our proposed distributed cooperative rate splittingalgorithm.