Analysis of TCP performance for LTE-5G Millimeter Wave Dual Connectivity

The goal of this work is the analysis of the performance of the transport control protocol (TCP) in a Dual connectivity (DC) system, where both LTE and 5G millimeter wave (mmWave) were used in the radio access network, while a single user travels across the scenario. Since the user is moving, the interaction between the mmWave base stations (BSs) must be very efficient to avoid congestion events. This makes the analysis of DC very important. Simulation models based on open-source software frameworks were used to evaluate the performance of Dual connectivity for a 5G non-standalone (NSA) solution, where all the 5G base station traffic goes through the LTE base station. The scenarios proposed were defined in terms of non-line-of-sight/line-of-sight (NLOS/LOS) scenario, medium/high traffic, which are used to evaluate different TCP congestion control algorithms. The performance was then evaluated in terms of goodput, packet delivery ratio, standard deviation of bytes in-flight, and round-trip time. Simulation results showed that the number of bytes in-flight grows with high rates and large latencies caused by inter-BS communication. The mmWave medium is very sensitive to channel conditions specially in the middle point between mmWave BSs causing ping-pong effect during a handover (HO). At the beginning of the simulation some nodes overflow due to the aggressive slow start mechanisms, which turn to be very problematic for high traffic rates. In that sense, TCP Cubic proves to be a much reliable congestion control algorithm since it implements a hybrid slow start method

The Airborne Internet

Mineralogy & gem

Chapter The Airborne Internet

Mineralogy & gem

L-band Digital Aeronautical Communications System (LDACS) draft-maeurer-raw-ldacs-04

This document provides an overview of the architecture of the L-band Digital Aeronautical Communications System (LDACS), which provides a secure, scalable and spectrum efficient terrestrial data link for civil aviation. LDACS is a scheduled, reliable multi-application cellular broadband system with support for IPv6. LDACS shall provide a data link for IP network-based aircraft guidance. High reliability and availability for IP connectivity over LDACS are therefore essential

High-Throughput Air-to-Ground Connectivity for Aircraft

Permanent connectivity to the Internet has become the defacto standard in the second decade of the 21st century. However, on-board aircraft connectivity is still limited. While the number of airlines offering in-flight connectivity increases, the current performance is insufficient to satisfy several hundreds of passengers simultaneously. There are several options to connect aircraft to the ground, i.e. direct air-to-ground, satellites and relaying via air-to-air links. However, each single solution is insufficient. The direct air-to-ground coverage is limited to the continent and coastal regions, while the satellite links are limited in the minimum size of the spot beams and air-to-air links need to be combined with a link to the ground. Moreover, even if a direct air-to-ground or satellite link is available, the peak throughput offered on each link is rarely achieved, as the capacity needs to be shared with other aircraft flying in the same coverage area. The main challenge in achieving a high throughput per aircraft lies in the throughput allocation. All aircraft should receive a fair share of the available throughput. More specifically, as an aircraft contains a network itself, a weighted share according to the aircraft size should be provided. To address this problem, an integrated air-to-ground network, which is able to provide a high throughput to aircraft, is proposed here. Therefore, this work introduces a weighted-fair throughput allocation scheme to provide such a desired allocation. While various aspects of aircraft connectivity are studied in literature, this work is the first to address an integrated air-to-ground network to provide high-throughput connectivity to aircraft. This work models the problem of throughput allocation as a mixed integer linear program. Two throughput allocation schemes are proposed, a centralized optimal solution and a distributed heuristic solution. For the optimal solution, two different objectives are introduced, a max-min-based and a threshold-based objective. The optimal solution is utilized as a benchmark for the achievable throughput for small scenarios, while the heuristic solution offers a distributed approach and can process scenarios with a higher number of aircraft. Additionally, an option for weighted-fair throughput allocation is included. Hence, large aircraft obtain a larger share of the throughput than smaller ones. This leads to fair throughput allocation with respect to the size of the aircraft. To analyze the performance of throughput allocation in the air-to-ground network, this work introduces an air-to-ground network model. It models the network realistically, but independent from specific network implementations, such as 5G or WiFi. It is also adaptable to different scenarios. The aircraft network is studied based on captured flight traces. Extensive and representative parameter studies are conducted, including, among others, different link setups, geographic scenarios, aircraft capabilities, link distances and link capacities. The results show that the throughput can be distributed optimally during high-aircraft-density times using the optimal solution and close to optimal using the heuristic solution. The mean throughput during these times in the optimal reference scenario with low Earth orbit satellites is 20 Mbps via direct air-to-ground links and 4 Mbps via satellite links, which corresponds to 10.7% and 1.9% of the maximum link throughput, respectively. Nevertheless, during low-aircraft-density times, which are less challenging, the throughput can reach more than 200 Mbps. Therefore, the challenge is on providing a high throughput during high-aircraft-density times. In the larger central European scenario, using the heuristic scheme, a minimum of 22.9 Mbps, i.e. 3.2% of the maximum capacity, can be provided to all aircraft during high-aircraft-density times. Moreover, the critical parameters to obtain a high throughput are presented. For instance, this work shows that multi-hop air-to-air links are dispensable for aircraft within direct air-to-ground coverage. While the computation time of the optimal solution limits the number of aircraft in the scenario, larger scenarios can be studied using the heuristic scheme. The results using the weighted-fair throughput allocation show that the introduction of weights enables a user-fair throughput allocation instead of an aircraft-fair throughput allocation. As a conclusion, using the air-to-ground model and the two introduced throughput allocation schemes, the achievable weighted-fair throughput per aircraft and the respective link choices can be quantified

The U.S. M-Business Market: Fad or the future

M-Business is information available on any device, anywhere and at anytime, offering businesses in any industry the potential to expand markets, improve their services and reduce costs. The U.S. m-business market is still in its infancy and is a few years away from becoming a growth market. This is due to a few reasons, which are the lack of standards for connectivity and service, no real applications to support the market and the lack of strong encryption to support m-business and e-commerce. M-business is not a fad but a potential new channel for business operations. This thesis will address the issues of why the U.S. m-business is slow to mature and what is required for the U.S. m-business to become a growth market