A Framework for Massive Access and Radio Resource Management in Urban WLANs Stefan Aust NEC Communication Systems, Ltd., 1753 Shimonumabe, Nakahara-ku, Kawasaki, Kanagawa 211-8666, Japan Email: aust.st@ncos.nec.co.jp R. Venkatesha Prasad, Ignas G.M.M. Niemegeers EEMCS, Delft University of Technology, P.O. Box 5031, 2600 GA Delft, The Netherlands Email: rvprasad@ieee.org; I.G.M.M.Niemegeers@tudelft.nl Abstract—The challenge in future unlicensed wireless networks will be the coordination of spectrum access among wireless LAN (WLAN) nodes in high dense areas. New WLAN standards, such as IEEE 802.11ah, will provide optimized outdoor WLAN coverage with a range of 1 km, thus exceeding the number of associated WLAN nodes. Hence, massive access schemes are required in order to coordinate the wireless access among WLAN nodes and to mitigate mutual interference. In addition, various wireless networks will co-exist, such as WLANs and sensor networks, competing for channel access. Hence, a framework in order to coordinate WLANs and sensor networks in dense areas is essential. This paper is intended to outline the challenges of wireless access in urban WLANs and proposes a framework which considers the challenges of dense wireless access and discusses potential solutions. The contributions are twofold. A clustering framework is proposed to deal with the massive access of wireless nodes, in particular of IEEE 802.11ah WLAN nodes. Further, a radio resource monitoring and management (RRMM) is proposed to manage the co-existence among wireless networks. A novel system architecture is proposed and discussed in order to monitor and manage the WLAN access in highly dense urban areas. Index Terms—WLAN, sensor networks, IEEE 802.11ah, sub- 1 GHz, IEEE 802.15.4, massive access, radio resource manage- ment, monitoring. I. I NTRODUCTION The use of unlicensed and cost-efficient wireless LANs (WLANs) attracts cellular operators and service providers to provide ubiquitous wireless access for mobile users. Such networks would allow simple and cheap Internet access (dump pipes), while more effort could be concentrated on creating new services and offering solutions to increase the operator’s revenue. In addition there is a prediction that the WLAN traffic initiated by smart phone users would ramping up and would lead to over 10 billion devices worldwide in 2017 [1]. WLAN access in cities will increase and the integration of machine- to-machine (M2M) services and Internet-of-Things (IoT) will further increase the demand for wireless access. A trend can be observed in which WLAN traffic signifi- cantly increases in the access network of cellular providers. It has been reported in [2] that WLAN traffic is increasing, and has already reached a dramatic ratio of over 50% for WLAN traffic for some cellular operators, compared to the cellular initiated traffic volume. Fig. 1. Massive Access scenario in urban WLANs. In addition to the massive increase of wireless traffic, there is a challenge in the revenue which a cellular operator can obtain. The problem is that the wireless traffic increase rapidly in parallel to an increase of investment costs for infrastructure, e.g., to offer data pipes. Although, the amount of data traffic outperforms the costs, the network investments decrease the operator’s revenue. Further, high speed wireless access is provided by alternative systems, such as IEEE 802.11 WLANs, which provide more than 1 Gbps [3]. Thus, it can be predicted that WLANs will gain more attraction by cellular operators - from those who are ready to invest and want to deploy a next generation wireless system - and local service providers - from those who are looking into wireless transmission systems without licensing radio access - e.g., to setup a wireless Internet service. Fig. 1 illustrates a dense urban Second IEEE International Workshop on Global Trends in Smart Cities 2013 978-1-4799-0540-9/13/$31.00 ©2013 IEEE 93