Logistic regression for BLER prediction in 5G

In this work, a block error rate (BLER) predictor for 5G based on logistic regression is presented. The regression is fed with transmission parameters and channel statistics. With these features, the predictor can model the behaviour of the transmission chain, including the low parity channel code (LDPC). In particular, for each modulation and coding scheme (MCS), the regression model uses as features the mean of the SINR over the allocated resources and the squared distance to the mean. Moreover, a single model able to cope with a set of modulation and coding schemes (MCSs) at the expense of certain accuracy loss is also proposed, and its performance evaluated. Possible applications for the regression models such as end-to-end modelling or as part of the adaptive modulation and coding (AMC) function are explored. Results show that the model has excellent accuracy in a wide set of scenarios

A New Frequency Planning for Improved Capacity and Coverage in Sectorized OFDMA Cellular Networks

One of the main challenges in cellular systems is how to reduce Other Cells Interference (OCI) while keeping high spectral efficiency and high coverage probability. Since the beginning of cellular technologies, frequency planning with sectoring has been used to mitigate such OCI. However, in modern wireless Orthogonal Frequency Division Multiple Access (OFDMA) technologies much attention is being paid to more complex strategies like Coordintation Multi-Point transmission/reception (CoMP) techniques due to its higher performance. This paper presents a new frequency planning for sectorized cell networks. Simulation results show that this scheme considerably outperforms classical sectoring (CS) in terms of both capacity and coverage probability. In particular, for the case of hexagonal grid, the capacity improvement is around 6 b/s/Hz compared to CS while keeping a coverage probability higher than 0.9 for a 0 dB Signal to Interference plus Noise Ratio (SINR) threshold.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A New Tractable Model to Estimate the Uplink Inter-Cell Interference in LTE

This paper presents a tractable model to estimate the uplink Inter-Cell Interference (ICI) in fully loaded LTE networks. Interfering users are considered to be uniformly distributed in an annulus so that evaluation of the interference power is obtained asymptotically for a high number of users. Model validity is proved through Monte Carlo simulations, showing that analytical results are close to simulation results even for a low number of users per cell.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Coordinated Multicast/Unicast Transmission on 5G: A Novel Approach for Linear Broadcasting

Linear broadcasting services, with a scheduled programming, constitute a paramount tel-ecommunication service for today’s society. Although the existing technology is mature, current linear broadcast systems have serious limitations when providing service to moving users or users placed in areas with complex orography and poor signal quality. To over-come these limitations, 3GPP 5G standard has included a work item to support 5G mul-ticast/broadcast services for future Release 17. This paper investigates the integration of point-to-point (unicast) communication with cellular multicast/broadcast on 5G technology to extend the current support of linear broadcasting services. This integration relies on the use mobile edge computing (MEC) at the 5G base station (gNB) to host a dynamic adap-tive streaming over HTTP (DASH) server that is coordinated with the multicast transmis-sion to complement the broadcast service. This approach join the reliability of point-to-point communications, with dedicated resources for each user, with the spectrum efficiency of multi-cast communications, where a set of users share common resources. The coopera-tion between those unicast and multicast schemes allows those users whose coverage is not good enough, to complete the linear broadcast flow through the point-to-point transmission via MEC. The benefits of such approach have been assessed with simulations in a realistic scenario that considers a vehicle moving across a sparsely populated region in southern Spain. Results reveals that throughput and bitrate playback (reproduction rate) are greatly improved when unicast/multicast integration is enabled since the number of stalling events is reduced significantly.This work has been partially supported by Radio Televisión Española through Impulsa Visión RTVE grant and by the Universidad de Málaga. We are grateful to Pere Vila, Esteban Mayoral Campos, Adolfo Muñoz Berrón and Miguel Ángel Bona San Vicente for their support and collaboration during the development of the project. Funding for open access charge: Universidad de Málaga / CBU

Doppler Spectrum Analysis in Three-Dimensional 5G Millimeter-Wave Channel Models

This article is contextualized in the mobile communications systems where there are multiple factors to consider: mobility, frequency, obstacles, reflectors, etc. In this paper, is presented an evaluation of the Doppler spectrum in a Three-Dimensional (3D) channel model for different frequencies, User Terminal (UT) directions and UT speeds. To commence, it introduces the channel model that is used for the simulations, then the Classical Doppler Spectrum frequently used in Two-Dimensional (2D) channel models is entered. Finally, it tries the Doppler Spectrum for the some typical 5G frequencies, speeds up to 500 km/h and for the motion direction in the 3D space.Spanish Government (Ministerio de Economia y Competitividad) and FEDER under grant TEC2016-80090-C2-1-R and by the Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech

Statistical Characterization of the Chunk Size Distribution in DASH

We present a statistical characterization of the segment size distribution of video streaming services based on dynamic adaptive streaming over HTTP (DASH). We first obtain the empirical distributions from traffic captures of available data sets encoded with different quality and segment size duration. Then, we determine the distributions that provide a better fit to the empirical data. We show that Weibull and truncated logistic distributions are adequate to modeling the chunk size distributions for a wide range of video qualities and segment size duration. Results are used to develop a source model for DASH traffic, implementing a synthetic generator of DASH-like video traces.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech. Proyecto Plan Nacional (Ministerio de Economia y Competitividad) TEC2016-80090-C2-1-R, y Universidad de Malag

Selección Dinámica de Celda en los Enlaces Ascendente y Descendente de Redes Heterogéneas: Estudio de las Estratégias Acoplada y Desacoplada

Dynamic cell selection (DCS) and decoupled access are two disruptive candidate schemes for cell association in future 5G networks. DCS provides adaptation to fast channel variations, which results in potential performance enhancement. On the other hand, decoupled accesses cope with the difference between uplink and downlink transmissions aiming to maximize their performance. In this paper, we investigate the performance such access schemes for both the downlink and the uplink with fractional power control (FPC) and compare them with different combinations of their static and coupled counter parts. Results reveal that decoupled access yields to a great fairness degree in the uplink, while the cost to pay is a minor reduction on the average rate. Additionally, dynamic cell selection with decoupled access leads to a high improvement of both fairness and average rate in the downlink and uplink.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Analytical Modeling of Distributed Location Based Access for Vehicular Ad Hoc Networks

One of the key ingredients of Intelligent Transportation Systems (ITS) is delivery of broadcast status messages among vehicles for safety purposes. This requires an efficient Medium Access Control (MAC) that provides low average delay and high reliability. To this end, Carrier Sense Multiple Access (CSMA) has been commonly proposed for Vehicle Ad Hoc Networks (VANETs). Nevertheless, the hidden-node problem can jeopardize the reliability of CSMA, whereas the latency when accessing the channel can be unbounded. To overcome these limitations, resource allocation based on the geo-location of the vehicles can be applied in VANETs. For example, a distributed location based access (DLOC) algorithm has been proposed such that vehicles access orthogonal resource blocks based on their position, aiming at maximizing the distance of co-channel transmitters. In this paper we propose a stochastic geometry approach to analyze DLOC taking into account path loss and fading as well as the random location of transmitting vehicles. Analytical results include the average interference, average binary rate and capture probability, i.e. probability of successful message transmission. It is shown that increasing the number of RBs increases reliability but there is a trade off between reliability and average BR.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Prestaciones de LTE sobre el canal aeronáutico

This work assesses the performance of Long Term Evolution (LTE) downlink over aeronautical channels associated to arrival, parking and en-route scenarios. The huge velocity related to some of these scenarios poses the following challenges: (1) (Inter-Carrier-Interference) ICI due to Doppler Shift, (2) ICI due to Doppler spread and (3) channel estimation errors. Taking into account these problems a physical layer LTE modem has been implemented. Results reveals that LTE can achive good performance in air-to-ground communications with aircraft moving at 1500 km/h without a complex receiver.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Radio interference analysis tool based on GNU Radio

Avoiding interference is one of the main challenges in radio communications. Interference hunting is usually done with costly instruments. In this work, a cost efficient portable tool is described for interference analysis that is based on software defined radio. A generic radio board implements the RF front end, while flexible signal processing is carried out on a personal computer. The proposed tool analyses spectrum characteristics spanning from 70 MHz to 6 GHz band, detects radio interference signals and helps to identify the type of radio technology used by the source transmitter.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech