Efficient LTE/Wi-Fi Coexistence in Unlicensed Spectrum Using Virtual Network Entity: Optimization and Performance Analysis

Abstract

Citation: DALILI SHOAEI, A., DERAKHSHANI, M. and LE-NGOC, T., 2018.Efficient LTE/WiFi coexistence in unlicensed spectrum using virtual network entity: Optimization and performance analysis. IEEE Transactions onCommunications, 66 (6), pp.2617-2629.Additional Information:• c 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Abstract-Long term evolution (LTE) operation in the unlicensed spectrum is a promising solution to address the scarcity of licensed spectrum for cellular networks. Although this approach brings higher capacity for LTE networks, the WiFi performance operating in this band can be significantly degraded. To address this issue, we consider a coordinated structure, in which both networks are controlled by a higher-level network entity. In such a model, LTE users can transmit in the assigned time-slots, while WiFi users can compete with each other by using p-persistent CSMA in their exclusive time-share. In an unsaturated network, at each duty cycle, the TDMA scheduling for LTE users and p values for WiFi users should be efficiently updated by the central controller. The corresponding optimization problem is formulated and an iterative algorithm is developed to find the optimal solution using complementary geometric programming (CGP) and monomial approximations. Aiming to address Quality-ofService (QoS) assurance for LTE users, an upper bound for average delay of these users are obtained. This analysis could be a basis for admission control of LTE users in unlicensed bands. The simulation results reveal the performance gains of the proposed algorithm in preserving the WiFi throughput requirement. I. INTRODUCTION A. Background & MotivationLTE operation on unlicensed bands, so-called unlicensed LTE (U-LTE), is considered by third-generation partnership project (3GPP) as a promising solution to meet the growing wireless data demand and to improve the spectrum efficiency. Although transmission across both unlicensed and licensed bands can boost LTE, such an approach may jeopardize the performance in WiFi systems solely operating on unlicensed bands for data transmission. The reason is that LTE networks exploit a schedule-based channel access, while in WiFi a contention-based scheme is applied, in which the user would randomly access the channel once it is detected idle. Therefore, in a coexistence scenario that both systems share the same channel, starvation may happen for WiFi as the whole airtime may be occupied by the LTE network [1]- [6].In order to address this issue, two approaches have been so far proposed, LTE-Unlicensed (LTE-U) and licensedassisted access (LAA). In LTE-U, developed in 3GPP Releases 10/11/12, a duty-cycle-based approach is used in which at each duty cycl...

High-Performance Long Range-Based Medium Access Control Layer Protocol

“…It also drives the MAC model to complete the networking process of the wireless ad hoc network, which initiates the initialization of the network and transmits data packets generated by the application layer. The MAC layer was based on the IEEE802.15.4g communication rules to control how to select wireless communication links when transmitting information [31,32]. The MAC layer protocol of LoRa supports CSMA and conflict avoidance technology [33,34].…”

Performance analysis of AUL FeLAA and WiFi coexistence in the presence of Rayleigh fading channel and capture effect under unsaturated traffic conditions

“…However, the ideal channel model and the saturation traffic load model are mostly invalid in the real coexistence scenario. The Rayleigh fading channel and the unsaturation traffic conditions have been adopted to analyze the WiFi alone system, but still not yet applied to the LAA-WiFi coexisting system [4,5]. To the best of our knowledge, the performance analysis for AUL FeLAA and WiFi coexistence accounting for unsaturation traffic load and Rayleigh fading channel has not been studied.…”