Lingjia Liu's Webpage

• Principal Investigator: Lingjia Liu (ECE at VT)
• Student Investigator: Bodong Shang (ECE at VT)
• Student Investigator: Jianan Bai (ECE at VT)
• Industrial Collaborator: Jianzhong (Charlie) Zhang (Samsung Research America)
• Industrial Collaborator: Hao Chen (Samsung Research America)
• Academic Collaborator: Harpreet S. Dhillon (ECE at VT)

<WRAP justify> Intellectual Merit: Heterogeneous networks, especially heterogeneous relay networks, are believed to be one of the enabling technologies for future broadband mobile communications. Previous design of such networks usually neglects the role of statistical queueing delay in performance analysis. However, most traffic of future broadband mobile data networks will be delay-sensitive while most delay-sensitive applications have stringent requirements on statistical delay-violation probabilities. For example, in the 4th generation cellular standard, the requirement on delay-violation probability for real-time video traffic is 2% with the delay bound being 50ms for radio access networks. The objective of this BRIGE research is to provide a unified fundamental framework for the analysis and design of heterogeneous relay networks under statistical delay constraints (constraints on delay violation probabilities). The research components of the project consist of two parts. The first part focuses on the statistical delay analysis of wireless multi-hop relay systems to provide a unified framework to analyze wireless system performance under delay-violation probability constraints. The second part focuses on heterogeneous relay networks where new mobile association strategies and load balancing methods will be identified to maximize the overall network efficiency for a heterogeneous relay network.

Broader Impacts: Mobile wireless devices are an integral part of society and are currently used by over 75% of the global population. In the United States, the present adoption rate of mobile devices exceeds 92%. Research that leads to improving their performance offers the potential to improve how these devices serve the needs of their users. In addition to global technological impact, the PI also proposes an educational plan that will immerse local students especially from the underrepresented groups in the exciting field of wireless communications. The PI's outreach activities span from the high school level up through the graduate level. The PI will also recruit students of underrepresented groups including Hispanic, female, low incoming and first generation students to participate in the project. By integrating research and education together, this project will broaden the participation of underrepresented groups in engineering.

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• Y. Li, L. Liu, H. Li, J. Zhang, and Y. Yi, “Resource Allocation for Delay-Sensitive Traffic over LTE-Advanced Relay Networks,” IEEE Trans. on Wireless Commun., vol. 14, no. 8, pp. 4291-4303, Aug. 2015.

• B. Ning, S. Yang, L. Liu, and Y. Lu, “Resource allocation for OFDM cognitive radio with enhanced primary transmission protection”. IEEE Commun. Lett., vol. 18, no. 11, pp. 2027-2030, Nov. 2014.

• G. Ru, H. Li, and L. Liu, “Energy efficiency of hybrid cellular with heterogeneous QoS provisions”. IEEE Communi. Lett., vol. 18, no. 6, pp. 1003-1006, Jun. 2014.

• L. Liu, Y. Yi, J.-F. Chamberland, and J. Zhang, “Energy-Efficient Power Allocation for Delay-Sensitive Multimedia Traffic over Wireless Systems”. Special Section on Green Mobile Multimedia Communications of the IEEE Trans. on Veh. Technol., vol. 63, no. 5, pp. 2038-2047, Jun. 2014.

• T. Tran, H. Li, G. Ru, R. Kerczewski, L. Liu, S. Khan, “Secure Wireless Multicast for Delay-Sensitive Data via Network Coding”. IEEE Trans. on Wireless Commun., vol. 12, no. 7, pp. 3372-3387, Jul. 2013.

• Y. Li, L. Liu, H. Li, Y. Li, and Y. Yi, “Adaptive Resource Allocation for Heterogeneous Traffic over Heterogeneous Relay Networks”. 2013 IEEE International Conference on Communications (ICC’13), pp. 5431-5436, Jun. 2013.

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