Long term evolution in high speed railway environments: Feasibility and challenges

2013 ◽  
Vol 18 (2) ◽  
pp. 237-253 ◽  
Author(s):  
Jaime Calle-Sanchez ◽  
Mariano Molina-Garcia ◽  
Jose I. Alonso ◽  
Alfonso Fernandez-Duran
2018 ◽  
Vol 2 (1) ◽  
Author(s):  
Sapta Nugraha

Abstract4G Long Term Evolution (LTE) has a standard for wireless communication with high-speed data access on cellular phones which have standard parameter i.e. power control. Power control is a method to avoid interference inter-users, as a result of power variations. Interference inter-users will cause performance limitations of the quality of service telecommunications operator. In this paper, we will design power control on the uplink channel based on the Signal to Interference Ratio (SIR) so that power level of mobile station (MS) are approximately equal. Simulation results show that power of MS can reach -7 dB, average time above 17 ms. The results of the SIR can order MS to equalize the SIR power levels transmitted by some MS with SIR reference value. Keywords: power control, uplink channel, SIR, mobile station Abstrak4G Long Term Evolution (LTE) memiliki standar komunikasi nirkabel akses data berkecepatan tinggi pada telepon seluler yang memiliki parameter standar yaitu kendali daya. Kendali daya merupakan metode untuk menghindari interferensi antar pengguna akibat variasi daya. Interferensi antar pengguna menyebabkan keterbatasan kinerja kualitas layanan operator telekomunikasi. Pada penelitian ini, akan dirancang kendali daya kanal uplink berdasarkan SIR agar daya mobile station (MS) mendekati sama. Hasil simulasi menunjukkan bahwa daya MS dapat mencapai -7 dB, rerata waktu di atas 17 ms. Hasil menunjukkan SIR dapat memerintahkan MS menyamakan daya yang ditransmisikan beberapa MS dengan nilai SIR referensi. Kata Kunci: kendali daya, kanal uplink, SIR, mobile station


2018 ◽  
Vol 7 (3.3) ◽  
pp. 255 ◽  
Author(s):  
E Sujatha ◽  
Dr C. Subhas ◽  
Dr M. N. Giri Prasad

Error-correction Coding plays a vital role to obtain efficient and high quality data transmission, in today’s high speed wireless communication system. Considering the requirement of using high data rates by Long Term Evolution (LTE) system, parallel concatenation of two convolutional encoders were used to design turbo encoder. In this research task a high speed turbo encoder, which is a key component in the transmitter of wireless communication System, with memory based interleaver has been designed and implemented on FPGA for 3rd Generation Partnership Project (3GPP) defined Long Term Evolution – Advanced (LTE-A) standard using Finite state Machine(FSM) encoding technique. Memory based quadratic permutation polynomial (QPP) interleaver shuffles a sequence of binary data and supports any of the 188 block sizes from N= 40 to N= 6144. The proposed turbo encoder is implemented using 28nm CMOS technology and achieved 300 Mbps data rate by using 1% of available total hardware logic. By using the proposed technique, encoded data can be released continuously with the help of two parallel memories to write/read the input using pipelining concept.  


Author(s):  
Hussain Mahdi ◽  
Baidaa Al-Bander ◽  
Mohammed Hasan Alwan ◽  
Mohammed Salah Abood ◽  
Mustafa Maad Hamdi

<p class="Abstract"><span lang="EN-US">Moving is the key to modern life. Most things are in moving such as vehicles and user mobiles, so the need for high-speed wireless networks to serve the high demand of the wireless application becomes essential for any wireless network design. The use of web browsing, online gaming, and on-time data exchange like video calls as an example means that users need a high data rate and fewer error communication links. To satisfy this, increasing the bandwidth available for each network will enhance the throughput of the communication, but the bandwidth available is a limited resource which means that thinking about techniques to be used to increase the throughput of the network is very important. One of the techniques used is the spectrum sharing between the available networks, but the problem here is when there is no available channel to connect with. This encourages researchers to think about using scheduling as a technique to serve the high capacity on the network. Studying scheduling techniques depends on the Quality-of-Service (QoS) of the network, so the throughput performance is the metric of this paper. In this paper, an improved Best-CQI scheduling algorithm is proposed to enhance the throughput of the network. The proposed algorithm was compared with three </span><span lang="MS">user scheduling algorithms to evaluate the throughput performance which are Round Robin (RR), Proportional Fair (PF), and Best-CQI algorithms. The study is performed under Line-of-Sight (LoS) link at carrier frequency 2.6 GHz to satisfy the Vehicular Long Term Evolution (LTE-V) with the high-speed scenario. The simulation results show that the proposed algorithm outperforms the throughput performance of the other algorithms.</span></p>


2019 ◽  
Vol 9 (23) ◽  
pp. 5240 ◽  
Author(s):  
Attila Hilt

The deployment of new radio access technologies always provides a good opportunity and timing to optimize the existing mobile front- and backhaul (commonly called “anyhaul”). The legacy systems (Long-Term Evolution (LTE), High-Speed Packet Access (HSPA), third-generation mobile (3G), second-generation mobile (2G)) already extensively utilize the transmission and transport capacities of the mobile anyhaul. With the current launch of 5G (fifth-generation mobile) and recent LTE-A (Advanced Long-Term Evolution), additional new transmission capacities are required again. Depending on the traffic and network topology, additional cell sites are built, and even more locations are connected with fiber optics. The existing microwave and millimeter-wave links are rotated toward those aggregation points that already have optical-fiber access. Due to the increased cell-site density, the average distance of the radio access links can be reduced by network and topology optimization. The reduced hop lengths combined with adaptive modulation and automatic power control bring an opportunity for capacity increase in shortened radio links. Links newly deployed for 5G find a wide spectrum in the millimetric V, E, W, and D frequency bands. This paper discusses the availability and hop-length targets of the anyhaul links that should be carefully kept by proper planning and monitoring.


Sign in / Sign up

Export Citation Format

Share Document