Small-Cell Traffic Balancing Over Licensed and Unlicensed Bands

Abstract

The 3rd Generation Partnership Project (3GPP) recently started standardizing the "Licensed-Assisted Access using LTE" for small cells, referred to as Dual Band Femtocell (DBF) in this paper, which uses LTE air interface in both licensed and unlicensed bands based on the Long Term Evolution (LTE) carrier aggregation feature. Alternatively, the Small Cell Forum introduced the Integrated Femto-WiFi (IFW) small cell which simultaneously accesses both the licensed band (via cellular interface) and the unlicensed band (via WiFi interface). In this paper, a practical algorithm for IFW and DBF to automatically balance their traffic in licensed and unlicensed bands, based on the realtime channel, interference and traffic conditions of both bands is described. The algorithm considers the fact that some "smart" devices (sDevices) have both cellular and WiFi radios while some WiFi-only devices (wDevices) may only have WiFi radio. In addition, the algorithm considers a realistic scenario where a single small cell user may simultaneously use multiple sDevices and wDevices via either the IFW, or the DBF in conjunction with a Wireless Local Area Network (WLAN). The goal is to maximize the total user satisfaction/utility of the small cell user, while keeping the interference from small cell to macrocell below predefined thresholds. The algorithm can be implemented at the Radio Link Control (RLC) or the network layer of the IFW and DBF small cell base stations. Results demonstrate that the proposed traffic-balancing algorithm applied to either IFW or DBF significantly increases sum utility of all macrocell and small cell users, compared with the current practices. Finally, various implementation issues of IFW and DBF are addressed.

Device-to-Device communications in LTE-Unlicensed heterogeneous network

“…However LTE is a demand-based system, so a critical element of LTE-U is to ensure fairness for Wi-Fi and other unlicensed users. In [8], an example of LTE-U channel access scheme is presented, where the femtocell base station (fBS) senses the unlicensed channel. If it is clear the link will access the unlicensed band, if not the fBS assigns the LTE licensed resource.…”

Embedding LTE-U within Wi-Fi Bands for Spectrum Efficiency Improvement

“…LTE-U technology allows users to access both licensed and unlicensed spectra under a unified LTE network infrastructure. It can provide better link performance, medium access control (MAC), mobility management, and larger coverage than simple Wi-Fi offloading [1], [2].…”

Licensed and Unlicensed Spectrum Allocation in Heterogeneous Networks

“…Resource allocation over multiple RATs has been studied in [22]- [24]. In [22], the authors presented a scheme for balancing licensed and unlicensed traffic in the case of a single femto user and single WiFi user.…”

“…Resource allocation over multiple RATs has been studied in [22]- [24]. In [22], the authors presented a scheme for balancing licensed and unlicensed traffic in the case of a single femto user and single WiFi user. In [23], [24], joint licensed and unlicensed resource allocation algorithms were proposed for licensed-assisted access systems for throughput and energy efficiency maximization, respectively.…”