Joint Channel Assignment and Occupancy Time Optimization in Frame-Based Listen-Before-Talk

We study the performance optimization problem of the long term evolution (LTE) network operating in the unlicensed band and sharing it with an existing WiFi network. We consider the LTE network to be based on the frame-based listen-before-talk protocol. We formulate the joint channel assignment and channel occupancy time optimization problem using a stochastic integer programming (IP) model. By applying the Lyapunov drift-plus-penalty theorem, we develop an asymptotically optimal solution with polynomial time-complexity for the stochastic IP problem. Numerical results are presented and the performance of the proposed solution is compared to the performance of two alternative approaches in which the channel assignment and channel occupancy time are determined sequentially

Performance Analysis of LTE Random Access Protocol with an Energy Harvesting M2M Scenario

In this article, we analyze the performance of the long-term evolution random access procedure with the Third Generation Partnership Project's access class barring (ACB) mechanism in an energy harvesting (EH) machine-to-machine (M2M) scenario. To circumvent the state-space explosion in the conventional Markov-chain-based analysis due to time-dependent traffic pattern and data and energy buffer status, we develop an analytical model that combines mean-value analysis with the Markov-based analysis. Based on the analytical model, the random access success probability, the access delay of the network, and the average time duration between two successive successful transmissions are derived. Our analysis suggests that in the EH scenario, despite the lower number of the contending nodes in comparison with the non-EH scenario, the ACB parameters must be chosen in a more conservative way to avoid excessive collisions. The ACB parameters include access barring rate and mean barring duration. We also study an energy threshold-based activation policy and investigate the joint effects of this policy and the ACB mechanism on the random access success probability. The extensive simulations were conducted to evaluate the accuracy of the analytical model