Hybrid Cellular/WLAN with Wireless Offloading: Enabling Next Generation Wireless Networks

The exploitation of already deployed wireless local area networks (WLAN)s (e.g., WiFi access points (AP)s) has attracted considerable attention, as an efficient and practical method to improve the performance of beyond 4G wireless networks. In this paper, we propose a novel communication paradigm to satisfy the performance demands of future wireless networks: a hybrid Cellular/WLAN network architecture with wireless offloading. In contrast to the commonly adopted practice of WiFi offloading, where the WLAN APs have a wired backhaul (e.g., Digital Subscriber Line), we propose a wireless offloading approach, where the WLAN APs will share their wireless cellular broadband connection with other users. These users will select their serving node, i.e., the macro-cell eNodeB or a WLAN AP, based on a certain selection criterion. Thus a challenging research field is originated, where interfering effects and wireless resources limitations play a dominant role. Important performance metrics of the proposed hybrid scheme, including the bit error probability, the ergodic capacity and the average signal-to-interference-plus noise ratio (SINR), are theoretically studied and closed form expressions are derived for the single-user case with multiple interferers, for both identical and non-identical fading conditions. Also, based on the general multi-cellular hybrid WLAN/Cellular concept, we first propose a intercell interference minimization approach. Then we present a novel scheme for achieving frequency reuse equal to one within a single macro-cell, under specific performance criteria and constraints, that guarantee the overall cell’s or the individual user’s quality-ofservice requirements. For the latter case we consider two optimization problems that aim at the overall cell’s SINR maximization or at the minimum user’s SINR maximization. For all optimization problems, fast greedy solutions presented. Numerical results and simulations show that the proposed wireless architecture P. S. Bithas is with the Institute for Astronomy, Astrophysics, Space Applications and Remote Sensing, National Observatory of Athens, Greece (e-mail:[email protected]). A. S. Lioumpas is with Cyta Hellas, Athens, Greece (e-mail: [email protected]) G. K. Karagiannidis is with the Department of Electrical and Computer Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece (e-mail: [email protected]) Bayan S. Sharif is with the Electrical & Computer Engineering Department, Khalifa University, UAE, and with the School of Electrical and Electronic Engineering, Newcastle University, UK. Partly funded by the EU project RERUM, REliable, Resilient and secUre IoT for sMart city applications, Project Number and type: 609094 STREP. March 22, 2016 DRAFT SUBMITTED TO IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1 may offer significant performance gains in the presence of multiple interferers, compared to a conventional cellular network. Index Terms Capacity, heterogeneous networks, hybrid Cellular/WLAN, next generation cellular networks, signal to interference and noise ratio, tethering, WiFi integration, wireless offloading.