Performance analysis of contending customer equipment in wireless networks

NoInitial ranging is the primary and important process in wireless networks for the customer premise equipments (CPEs) to access the network and establish their connections with the base station. Contention may occur during the initial ranging process. To avoid contention, the mandatory solution defined in the standards is based on a truncated binary exponential random backoff (TBERB) algorithm with a fixed initial contention window size. However, the TBERB algorithm does not take into account the possibility that the number of contended CPEs may change dynamically over time, leading to a dynamically changing collision probability. To the best of our knowledge, this is the first attempt to address this issue. There are three major contributions presented in this paper. First, a comprehensive analysis of initial ranging mechanisms in wireless networks is provided and initial ranging request success probability is derived based on number of contending CPEs and the initial contention window size. Second, the average ranging success delay is derived for the maximum backoff stages. It is found that the collision probability is highly dependent on the size of the initial contention window and the number of contending CPEs. To achieve the higher success probability or to reduce the collision probability among CPEs, the BS needs to adjust the initial contention window size. To keep the collision probability at a specific value for the particular number of contending CPEs, it is necessary for the BS to schedule the required size of the initial contention window to facilitate the maximum number of CPEs to establish their connections with reasonable delay. In our third contribution, the initial window size is optimized to provide the least upper bound that meets the collision probability constraint for a particular number of contending CPEs. The numerical results validate our analysis

A 6G White Paper on Connectivity for Remote Areas

In many places all over the world rural and remote areas lack proper connectivity that has led to increasing digital divide. These areas might have low population density, low incomes, etc., making them less attractive places to invest and operate connectivity networks. 6G could be the first mobile radio generation truly aiming to close the digital divide. However, in order to do so, special requirements and challenges have to be considered since the beginning of the design process. The aim of this white paper is to discuss requirements and challenges and point out related, identified research topics that have to be solved in 6G. This white paper first provides a generic discussion, shows some facts and discusses targets set in international bodies related to rural and remote connectivity and digital divide. Then the paper digs into technical details, i.e., into a solutions space. Each technical section ends with a discussion and then highlights identified 6G challenges and research ideas as a list.Comment: A 6G white paper, 17 page

TCP congestion control macroscopic behavior for combinations of source and router algorithms

Abstract: The network side of Transmission Control Protocol (TCP) congestion control is normally considered a black-box in performance analysis. However, the overall performance of TCP/IP networks is affected by selection of congestion control mechanisms implemented at the source nodes as well as those implemented at the routers. The paper presents an evaluation of macroscopic behaviour of TCP for various combinations of source algorithms and router algorithms using a Dumbbell topology. In particular we are interested in the throughput and fairness index. TCP New Reno and TCP Cubic were selected for source nodes. Packet First-in-First-out (PFIFO) and Controlled Delay (CoDel) mechanisms were selected for routers. The results show that TCP New Reno performs well, in terms of throughput, in a low BDP scenario. However, as expected in high BDP scenario, TCP New Reno deteriorates and TCP Cubic performs better. CoDel in the network side further deteriorates TCP New Reno flows in high Bandwidth-Delay Product (BDP) scenario, while considerably improving TCP Cubic. PFIFO deteriorates both TCP Cubic and TCP New Reno in high BDP. Almost in all cases CoDel seems to improve fairness

Improving Rural Emergency Services with Cognitive Radio Networks in Sub-Saharan Africa

International audienceIn this paper, we propose a new approach based on Cognitive Radio technology to address the challenges for ensuring connectivity in remote areas of Africa. Indeed, the current network coverage is concentrated around the cities with high density of population. Through the deployment of Cognitive Radio, emergency services in rural areas will benefit from low cost access networks. Cognitive Radio will be used to manage the selection/switching across different frequency UHF/VHF bands or TV White Spaces

Intelligent future wireless networks for energy efficiency. Overall analysis and standardization activities

This book chapter addresses a number of issues related to standardization and regulatory policies aiming at promoting energy-efficient communications (both wired and wireless) and networking, highlighting the need for a synergic approach. It encompasses the analysis of various solutions supporting sophisticated energy management within each layer of the OSI stack model in the con- text of wireless networking, as well as the overview of cross-layer energy-efficient applications. In every part of this chapter, adequate references to the corresponding standardization activities on the European and global level have been identified. Finally, the steps toward implementation of energy- efficient networking solutions by means of CR technologies are presented. The rest of the chapter is arranged as follows. First, the role of separate OSI layers on energy consumption is discussed, with particular emphasis put on the holistic view on the whole processing done in these layers. Then, the mutual dependencies between the neighboring layers are analyzed from the perspective of energy saving. This layer-centric and cross-layer discussion is followed by the presentation of the current challenges and opportunities of the future wireless systems. Finally, in that light, ongoing standardization activities are presented