Assuring an uninterrupted high Quality of Service (QoS) of railway communications between on-board terminals and base stations creates challenges for the provider. This is partly explained by the inherent mobility and the high penetration loss of carriages. Deploying mobile relays in public transportation is possible with a 100%-compatible LTE/EPC architecture. This effectively ensures that the electromagnetic insulation is kept to a minimum as QoS on board can be dramatically affected and worsened within the railway vehicles. Yet all users’ traffic congregates via the radio backhaul link and needs to take into consideration the extra packet-overhead and signaling messages that as a general rule get transmitted via the fixed links. The paper’s aim is to analyze the performance of mobile relays in loaded conditions comparing this to the standard direct mode. We propose an analytical model to compute the signaling rate. We parametrize it with experiments done on a testbed with real radio transmissions and show that signaling has no major impact on performance. We then evaluate the QoS experienced by passengers by means of simulations for two representative services: Web browsing and voice communications. The packet loss ratio for voice communications is reduced at the expense of a slight end-to-end latency increase thanks to mobile relays. During the high load conditions there is a significant reduction in the load time of a Web page and the throughput is increased.
In this paper, we propose a sleep strategy for energy-efficient 5G Base Stations (BSs) with multiple Sleep Mode (SM) levels to bring down energy consumption. Such management of energy savings is coupled with managing the Quality of Service (QoS) resulting from waking up sleeping BSs. As a result, a tradeoff exists between energy savings and delay. Unlike prior work that studies this problem for binary state BS (ON and OFF), this work focuses on multi-level SM environment, where the BS can switch to several SM levels. We propose a Q-Learning algorithm that controls the state of the BS depending on the geographical location and moving velocity of neighboring users in order to learn the best policy that maximizes the tradeoff between energy savings and delay. We evaluate the performance of our proposed algorithm with an online suboptimal algorithm that we introduce as well. Results show that the Q-Learning algorithm performs better with energy savings up to 92% as well as better delay performance than the heuristic scheme.
In 5G networks, specific requirements are defined on the periodicity of Synchronization Signaling (SS) bursts. This imposes a constraint on the maximum period a Base Station (BS) can be deactivated. On the other hand, BS densification is expected in 5G architecture. This will lead to an energy crunch if kept ignored. In this paper, we propose a distributed algorithm based on Reinforcement Learning (RL) that controls the states of the BSs while respecting the requirements of 5G. By considering different levels of Sleep Modes (SMs), the algorithm chooses how deep a BS can sleep according to the best switch-off SM level policy that maximizes the trade-off between energy savings and system delay. The latter is calculated based on the wake-up time required by the different SM levels. Results show that our algorithm performs better than the case of using only one type of SM. Furthermore, our simulations show a gain in energy savings up to 90% when the users are delay tolerant while respecting the periodicity of the SS bursts in 5G.
Deploying mobile relays in public transportation is a simple yet effective way to avoid the electromagnetic insulation within vehicles and to increase the Quality of Service (QoS) perceived by passengers, which is sometimes low. Mobile relaying can be done by using an LTE/EPC 100%-compatible architecture. However, this solution induces extra-overhead. In this paper we evaluate the QoS of an LTE mobile relay architecture for public railway transport systems for two representative services: client-server requests and voice communications. We compare the performance of a direct transmission against a mobile relay architecture for different types of requests and different load conditions. This work, therefore, evaluates the mobile relay performance in terms of load time, throughput, packet loss ratio and end-to-end latency. Our findings show that a mobile relay architecture highly improves the QoS performance for train passengers. Furthermore, the gain is greater as the load increases.
Psychology and computer science are two scientific disciplines that focus on identifying the specific characteristics of information processing. The first analyzes human behavior, while the latter focuses on the construction of a technical tool that seeks to emulate the brain: the computer. Therefore, psychology is strongly tied to the moment people choose their passwords. Deceptive advertising often compensates through money, free products, services or other self-esteem tests to influence a product or service to appear on your social network, in order to increase their consumption among its followers and to take personal information without your consent. Security is subjective, and each individual will perceive security differently, since each person has different weaknesses. Subjectivity should not be the one who meditates to manage his own measures of protection against the Social Engineering, which refers to psychological manipulation of people into performing actions or divulging confidential information. This project is also based on the need to prevent attacks of information subtraction by obtaining and decrypting the keys of access, or in the worst case, obtaining passwords directly to the different services, bank accounts, credit cards of individuals, based on the information that a people exposed or share on their social networks. Additionally, it focuses on how attackers could obtain or decipher their passwords based on personal information obtained from such advertisements; providing a better vision of how hackers use the psychology applied to information security.
Authors tend to express themselves using language in ways that reflect particular styles, vocabularies, biases, idioms, etc. These features can be captured in the so-called firm or stylone. Although capturing these attributes with high fidelity has proven to be very challenging, some advances have been made. Stylometry is the analysis of the unique attributes that are expressed by an author unconsciously through his or her publications. In this paper we investigate techniques for the detection of authorship patterns from the text content of a large number of digital documents, including e-mails, academic notes and free redaction in the Spanish language. A mechanism based on pondering parameters, including statistical observations, extracting a pattern is proposed. We defined 150 stylistic criteria parameters adapted to the Spanish language to compute our metric. Extensive experiment results are also presented.
Instant Messaging in mobile devices can be considered one of the most used services in mobile communications. Security prop- erties such as integrity and confidentiality must be maximized. This paper proposes a new symmetric encryption mechanism for instant text messaging in mobile devices. Our mechanism uses a sequence of prime numbers obtained from a bi-dimensional ma- trix and a secret key for the encryption process. The proposed solution has been compared with other well-known symmetric and asymmetric algorithms such as DES, AES, RSA, MD2, MD5, SHA. Results show that symmetrical mechanisms are more efficient for instant messaging and that our mechanism is suitable for the encryption of instant text messaging in mobile devices due to its low complexity, performance, robustness and ease of implementation.
Long Term Evolution (LTE) Networks were proposed for serving a multitude of high-speed data-rate services. For such systems, the Quality of Service (QoS) at the wireless part needs to be guaranteed by using smart, fast and strong resource allocation mechanisms. In order to build such algorithms, several parameters such as channel conditions, packet delays, queue length sizes and flow bitrates should be used to compute a maximization metric. Most authors compute such metric by obtaining the product of the afore-mentioned parameters. We consider this fact as a huge mistake. In this paper, we analyse the relevance of each parameter and give them different pounds. We propose a new resource allocation algorithm that presents a low complexity level. It works in a heterogeneous service scenario real time (RT) and non-Real Time (NRT). In order to evaluate the performance of our algorithm, several QoS constraints such as throughput, Packet Loss Ratio (PLR) and Fairness Index (FI) are used.
The LTE specifications provide QoS for multimedia services with fast connectivity, high mobility and security. However, 3GPP specifications have not defined scheduling algorithms to exploit the LTE characteristics to support real time services. In this article we propose a two level scheduling scheme composed by cooperative game theory, a virtual token mechanism, and the well known algorithms EXP-RULE and Modified-Largest Weighted Delay Firs (M-LWDF) in downlink system. By using cooperative game theory such as bankruptcy game and Shapley value, the proposed mechanism works by forming coalitions between flow classes to distribute the bandwidth fairly among all of them. Both algorithms EXP-RULE and M-LWDF have been modified to use a virtual token mechanism to improve their performance, giving priority to real time flows. By taking the arrival rate of packets into account, the proposed mechanism partially included in previous schedulers has been adapted to this work to increase remarkably the performance of the resource allocation for real time flows. The performance evaluation is conducted in terms of system throughput, Packet loss ratio, total cell spectral efficiency, delay and fairness index.
Long-Term Evolution (LTE) is a new radio access technology proposed by the third-generation partnership project (3GPP) in order to provide a smooth migration toward fourth-generation (4G) wireless systems. The 3GPP LTE uses orthogonal frequency division multiple access (OFDMA) in the downlink. The OFDMA technology divides the available bandwidth into multiple narrow-band subcarriers and allocates a group of subcarriers to a user based on its requirements, current system load, and system configuration.
The 3GPP LTE radio network architecture consists of only one node between the user and the core network known as eNodeB which is responsible to perform all radio resource management (RRM) functions. Packet scheduling is one of the RRM functions and it is responsible for intelligent selections of users and transmissions of their packets such that the radio resources are efficiently utilized and the users’ quality of service (QoS) requirements are satisfied.
In order to enhance the Quality of Service in LTE, femtocell architecture has been proposed as a promising solution. However, interference is the main weak point in femtocell scenarios which causes a serious impact on multimedia services performance. Femtocell interference mitigation in LTE networks is the principle objective of this paper. We propose an enhancement of the well known four-coloring method for interference mitigation by combining it with cooperative game theory. Our proposed scheme aims to provide a solution to effectively achieve femtocell interference mitigation while guaranteeing the bitrate application for real-time services. The basic metrics of quality of service (QoS) such as throughput, Packet Loss Ratio (PLR), delay and Signal-to-Interference-plus-Noise-Ratio (SINR) are investigated. Our simulation environment is derived from realistic scenarios in order to study the performance of real-time service like Video and VoIP applications. Throughout our numerical results, we demonstrate the improvement of QoS constraints along with balancing between interference reduction requirement and resource allocation efficiency for real-time applications.
In this paper a two level resource allocation scheme is proposed to enhance the Quality of Service (QoS) for multimedia services in LTE downlink system. It corresponds to a solution that combines cooperative game theory, a virtual token mechanism, and the EXP-RULE algorithm. By using cooperative game theory such as bankruptcy game and Shapley value, the proposed mechanism works by forming coalitions between flow classes to distribute bandwidth fairly. EXP-RULE algorithm has been modified to use a virtual token mechanism to improve its performance. By taking into account constraints such as Shapley value fairness and the virtual token robustness, the proposed mechanism can increase remarkably the performance for real time flows such as video and VoIP in downlink system. The performance evaluation is conducted in terms of system throughput, packet loss ratio (PLR), cell spectral efficiency and fairness index.
The LTE specification provides QoS of multimedia services with fast connectivity, high mobility and security. However, 3GPP specifications have not defined scheduling algorithms to support real time and non-real time application services. In this paper we propose a two level scheduling scheme composed by cooperative game concept and EXP-RULE scheduling algorithm. By using cooperative game theory such as bankruptcy game and Shapley value, the proposed mechanism works by forming coalition between flow classes to distribute the bandwidth fairly. To make a performance judgment, the proposed downlink scheduling scheme has been compared to other well known schedulers such as M-LWDF and PF. Simulation results show that the proposed scheme can improve the performance on the used metrics among services. The performance evaluation is conducted in terms of system throughput, packet loss ratio (PLR), cell spectral efficiency and fairness Index.
The LTE specification provides QoS of multimedia services with fast connectivity, high mobility and security. However, 3GPP specifications have not defined scheduling algorithms to support real time and non-real time application services. In this paper we propose a modified version of M-LWDF and EXP/PF scheduling algorithms based on token mechanism, which provide better performance to real time flows such as video and VoIP in downlink system. By taking the arrival rates of packets to queues into account, the proposed mechanism included in previous scheduling algorithms, can increase remarkably the bit-rate for multimedia services. Simulation results show that the proposed modified algorithms can achieve a throughput gain for real time services specially for video traffic. Performance evaluation is conducted in terms of system throughput and packet loss ratio (PLR).