scholarly journals Performance analysis of a novel method for fast handovers in TDD and FDD for long term evolution

2018 ◽  
Vol 7 (1.9) ◽  
pp. 115
Author(s):  
G K.Venkatesh ◽  
P V.Rao
Keyword(s):  
Mobile Network ◽  
Wireless Channel ◽  
Access Time ◽  
Wireless Link ◽  
Time Division Duplex ◽  
Handover Delay ◽  
Term Evolution ◽  
Time Division

The LTE Long Term Evolution highly developed Technology, Handover is the essential function of the mobility of user in cellular networks in Time Division Duplex as well as Frequency Division Duplex. Handover is one of the essential that can affect the [QoS] Quality of Service with Capacity of Mobile Broadband Networks. Within mobile cellular network communication systems, a (spectrum) limited shared resource needs to be shared with all the users, so full duplex communication is achieved. This paper involves studying diverse Hand over delay parameters and also focus on reducing “Hard Handover delay” by minimizing interruption time, activation time, wireless channel accesses time as well as the wireless link transmission delay. Technique is developed in order to reduce the handover delay time in Time Division Duplex network which too reduces the wireless channel access time and the wireless link transmission delay. A novel handover algorithm is developed which would decreases the handover delay time and access time inside mobile network environment.Additional work may be conceded on to obtain enhanced performance and Quality of service in Time Division Duplex mobile network.

scholarly journals Desain dan Implementasi Duplekser dengan Metoda Pseudo-Interdigital untuk Uplink dan Downlink LTE

2016 ◽  
Vol 13 (2) ◽  
pp. 73
Author(s):  
Enceng Sulaeman ◽  
Yaya Sulaeman ◽  
Asep Yudi Hercuadi
Keyword(s):  
Insertion Loss ◽  
Return Loss ◽  
Bandpass Filter ◽  
Long Term Evolution ◽  
Full Duplex ◽  
Frequency Division ◽  
Time Division Duplex ◽  
Term Evolution ◽  
Time Division

Duplekser merupakan perangkat yang dapat mengisolasi receiver dari transmitter saat keduanya saling berbagi antena yang sama, digunakan agar komunikasi bisa berjalan secara full duplex. Ada dua metode transmisi duplex yaitu frequency division duplex (FDD) dan time division duplex (TDD). FDD merupakan teknik duplex yang menggunakan dua frekuensi yang berbeda untuk melakukan komunikasi dalam dua arah, sedangkan TDD menggunakan frekuensi tunggal dan frekuensi tersebut digunakan oleh semua kanal untuk melakukan pengiriman dan penerimaan data. Gabungan dua bandpass filter dengan metoda pseudo-interdigital untuk aplikasi LTE (long term evolution). Metode ini lebih unggul dibandingkan duplekser dengan metoda hybrid. Duplekser bekerja pada FDD LTE band ke-7 yaitu frekuensi uplink 2500-2570 MHz dan downlink 2620-2690 MHz. Dari hasil pengukuran diperoleh sebagai berikut: nilai frekuensi center pada uplink 2639 MHz dan pada downlink 2659 MHz, insertion loss pada uplink 1,561 dB dan downlink 1,74 dB, bandwidth ±70 MHz, isolasi 23,03 dB, serta nilai return loss 23,5 dB pada uplink dan downlink 23,45 dB.

scholarly journals Joint power allocation and subcarrier assignment for device to device in 5G time division duplex networks

2018 ◽  
Vol 14 (11) ◽  
pp. 155014771881109 ◽  
Author(s):  
Pan Zhao ◽  
Lei Feng ◽  
Peng Yu ◽  
Wenjing Li ◽  
Xuesong Qiu
Keyword(s):  
Quality Of Service ◽  
Power Allocation ◽  
Base Station ◽  
Joint Power ◽  
Time Division Duplex ◽  
Device To Device ◽  
Minlp Problem ◽  
Device To Device Communication ◽  
Time Division

The explosive demands for mobile broadband service bring a major challenge to 5G wireless networks. Device-to-device communication, adopting side links for user-direct communication, is regarded as a main technical source for offloading large volume of mobile traffic from cellular base station. This article investigates the joint power and subcarrier allocation scheme for device-to-device communication in 5G time division duplex systems. In time division duplex system, instead of utilizing an exclusive portion of the precious cellular spectrum, device-to-device pairs reuse the subcarriers occupied by cellular users, thus producing harmful interference to cellular users in both uplink and downlink communication, and strongly limiting the spectrum efficiency of the system. To this end, we focus on the maximization of device-to-device throughput while guaranteeing both uplink and downlink channel quality of service of cellular users as well as device-to-device pairs. The problem is formulated as a mixed integer non-linear programming (MINLP) problem. To make it tractable, we separate the original MINLP problem into two sub problems: power allocation and sub-carrier reusing. The former is to develop optimal power allocation for each device-to-device pair and each cellular user, with the constraints of maximum power and quality of service. It is solved by geometric programming technique in convex optimization method. The latter is derived as a one-to-many matching problem for scheduling multiple subcarriers occupied by cellulars to device-to-device pairs. It is solved by Hungarian method. Simulation results show that the proposed scheme significantly improves system capacity of the device-to-device underlay network, with quality of service of both device-to-device users and cellular users guaranteed.

Broadcast Data Placement over Multiple Wireless Channels

2011 ◽  
pp. 155-176
Author(s):  
Dimitrios Katsaros ◽  
Yannis Manolopoulos
Keyword(s):  
Wireless Channels ◽  
Effective Means ◽  
Communication Technologies ◽  
Wireless Channel ◽  
Optimal Placement ◽  
Access Time ◽  
Portable Devices ◽  
High Bandwidth ◽  
Mobile Clients

The advances in computer and communication technologies made possible an ubiquitous computing environment were clients equipped with portable devices can send and receive data anytime and from anyplace. Due to the asymmetry in communication and the scarceness of wireless resources, data broadcast is widely employed as an effective means in delivering data to the mobile clients. For reasons like heterogeneous communication capabilities and variable quality of service offerings, we may need to divide a single wireless channel into multiple physical or logical channels. Thus, we need efficient algorithms for placing the broadcast data into these multiple channels so as to reduce the client access time. The present chapter discusses algorithms for placing broadcast data to multiple wireless channels, which cannot be coalesced into a lesser number of high-bandwidth channels, assuming that there are no dependencies among the transmitted data. We give an algorithm for obtaining the optimal placement to the channels and explain its limitation since it is computationally very demanding and thus unfeasible. Then, we present heuristic schemes for obtaining suboptimal solutions to the problem of reporting on their implementation cost and their relative performance.

scholarly journals Long-Term Evolution of Quality of Life and Symptoms Following Surgical Treatment for Endometriosis: Different Trajectories for Which Patients?

2020 ◽  
Vol 9 (8) ◽  
pp. 2461
Author(s):  
Aurélie Comptour ◽  
Céline Lambert ◽  
Pauline Chauvet ◽  
Claire Figuier ◽  
Anne-Sophie Gremeau ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Surgical Treatment ◽  
Short Form ◽  
Complete Information ◽  
Long Term Evolution ◽  
Epidemiological Methods ◽  
Multicenter Cohort Study ◽  
Term Evolution

Many studies have shown a global efficacy of laparoscopic surgery for patients with endometriosis in reducing painful symptoms and improving quality of life (QoL) in the short and long-term. The aim of this study was to analyze the different trajectories of long-term evolution in QoL and symptoms following surgical treatment for endometriosis, and to identify corresponding patient profiles. This prospective and multicenter cohort study concerned 962 patients who underwent laparoscopic treatment for endometriosis. QoL was evaluated using the Short Form (SF)-36 questionnaire and intensity of pain was reported using a visual analog scale prior to surgery and at 6, 12, 18, 24 and 36 months after surgery. Distinctive trajectories of pain and QoL evolution were identified using group-based trajectory modeling, an approach which gathers individuals into meaningful subgroups with statistically similar trajectories. Pelvic symptom trajectories (models of the evolution of dysmenorrhea, dyspareunia and chronic pelvic pain intensity over years) correspond to (1) patients with no pain or pain no longer after surgery, (2) patients with the biggest improvement in pain and (3) patients with continued severe pain after surgery. Our study reveals clear trajectories for the progression of symptoms and QoL after surgery that correspond to clusters of patients. This information may serve to complete information obtained from epidemiological methods currently used in selecting patients eligible for surgery.

scholarly journals High Speed Mobility Management Performance in a Real LTE Scenario

2020 ◽  
Vol 10 (1) ◽  
pp. 5175-5179
Author(s):  
A. A. M. K. Abuelgasim ◽  
K. M. Yusof
Keyword(s):  
High Risk ◽  
Mobility Management ◽  
High Speed ◽  
Field Measurements ◽  
Mobile Operator ◽  
Seamless Connectivity ◽  
Term Evolution ◽  
Network Technologies

This paper discusses the mobility management for high-speed users, which is a crucial challenge for all mobile operators, especially when users are moving vertically across different network technologies. Mobility, also known as seamless connectivity, is directly influencing the quality of service (QoS). Mobility management-Handover (HO) performance was evaluated by field measurements of a Long Term Evolution (LTE) network of a mobile operator in the Middle East. Drive test measurements were used to analyze the results of different high-speed scenarios. User Equipment (UE) with high speed of 80-140km/h causes a high risk of failure of seamless connectivity as the HO procedure timing is longer than for UE with smaller speed. HO failure and call drop may occur when UE is moving with high speed across two adjacent cells in highways. During measurements, HO failure occurred when UE speed was 140km/h, and HO preparation timing increased when UE speed increased.

scholarly journals Rendimiento de la técnica de acceso múltiple no ortogonal (NOMA) en un sistema de comunicación móvil Long-Term Evolution (LTE)

2020 ◽  
Vol 3 (1) ◽  
pp. 62-76
Keyword(s):  
Long Term Evolution ◽  
Frequency Division Multiplexing ◽  
Third Generation ◽  
Frequency Division ◽  
Time Division Multiplexing ◽  
Term Evolution ◽  
Time Division ◽  
Third Generation Partnership Project

La creciente demanda de datos a través de las redes móviles y la búsqueda de servicios más eficientes por parte de los usuarios han inducido a la generación de nuevas técnicas que incrementen la eficiencia espectral. El acceso múltiple no-ortogonal (NOMA) es una de las técnicas que están siendo evaluadas dentro del 3GPP (Third Generation Partnership Project), esta proporciona servicios a múltiples usuarios mediante multiplexación en potencia. Esta investigación evalúa el rendimiento de NOMA en sistemas LTE (Long Term Evolution) mediante simulaciones de capa física, en relación con las tecnologías de acceso múltiple ortogonales convencionales TDM (Time Division Multiplexing) y FDM (Frequency Division Multiplexing). Se compararán, además, las ganancias obtenidas, con las publicadas en la bibliografía de Advanced Television Systems Committee(ATSC) 3.0. Los resultados demuestran que NOMA es mejor que TDM en los casos que se utilice una tasa baja en el receptor móvil y una tasa media en el receptor fijo, demostrando ganancias de 3.35 y 0.25 respectivamente.

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