Long Term Evolution User Equipment Research Articles

Tunable Duplexers: Downlink Band Isolation Requirements for LTE User Equipment

Tunable duplexers based on self-interference cancellation present a promising alternative to fixed-frequency duplexers (e.g., surface acoustic wave devices), however the level of transmit-to-receive (Tx–Rx) isolation they provide is typically lower compared to acoustic devices. This letter quantifies the impact of reduced isolation on receiver (Rx) noise figure (NF), and determines minimum isolation requirements for Tx-Rx isolation in cellular handset transceivers. Measurements of Tx noise power spectral density from a cellular handset power amplifier are combined with theoretical analysis and long term evolution (LTE) downlink throughput simulations to assess the impact of isolation on the NF and sensitivity. Although lower duplexer isolation can lead to substantial desensitization for some duplex separation/bandwidth combinations, achieving LTE compliant sensitivity requires only 38 dB of isolation in the Rx band. LTE sensitivity specification compliance is therefore readily achievable with current tunable duplexing technologies.

Vehicle detection and classification using LTE‐CommSense

We demonstrated a vehicle detection and classification method based on Long Term Evolution (LTE) communication infrastructure based environment sensing instrument, termed as LTE-CommSense by the authors. This technology is a novel passive sensing system which focuses on the reference signals embedded in the sub-frames of LTE resource grid. It compares the received signal with the expected reference signal, extracts the evaluated channel state information (CSI) and analyzes it to estimate the change in the environment. For vehicle detection and subsequent classification, our setup is similar to a passive radar in forward scattering radar (FSR) mode. Instead of performing the radio frequency (RF) signals directly, we take advantage of the processing that happens in a LTE receiver user equipment (UE). We tap into the channel estimation and equalization block and extract the CSI value. CSI value reflects the property of the communication channel between communication base station (eNodeB) and UE. We use CSI values for with and vehicle and without vehicle case in outdoor open road environment. Being a receiver only system, there is no need for any transmission and related regulations. Therefore, this system is low cost, power efficient and difficult to detect. Also, most of its processing will be done by the existing LTE communication receiver (UE). In this paper, we establish our claim by analyzing field-collected data. Live LTE downlink (DL) signal is captured using modeled LTE UE using software defined radio (SDR). The detection analysis and classification performance shows promising results and ascertains that, LTE-CommSense is capable of detection and classification of different types of vehicles in outdoor road environment.

Evaluating the effect of mobility speed on the performance of three handover algorithms in long term evolution networks

This work uses NS3 simulation to study the effect of mobility speed on the performance of three handover algorithms in Long Term Evolution (LTE) Networks. A realistic multi-cell LTE network was set up using NS3 simulation software. Mobility models were used to vary the location of the User Equipment (UE), hence triggering handover events across the network. The performance was measured using Signal Interference Noise Ratio (SINR) and number of completed handovers. Result revealed that at a speed between the ranges of 0 – 3 km/h, the Integrative algorithm performed best while at 4 – 60km/h, the performance of the A3RSRP algorithm was the best with an average value of 95dB. Also, at an increased speed within the range of 60 – 120 km/h, the Integrative algorithm had a slightly better performance than the A3RSRP. However, at a speed above 120 km/h, the integrative algorithm performed best with an SINR of 120dB. In terms of completed handovers, the Integrative algorithm had the least number of completed handovers throughout the entire range of considered speeds. Thus, we establish that mobility speed has a significant effect on the performance of handover algorithms.Keywords: LTE handover, LTE UE Speed, Integrative Algorithm, Power Budget Algorithm

Coexistence of DC and CSMA in SRD channel access and resilience to LTE interference: A simulator‐based analysis

AbstractThe foreseen increased use of short‐range devices (SRDs) will boost the competition for radio channel access in license‐exempt frequency bands. Therefore, it is important to find out the most efficient SRD configurations in terms of their performance in high‐contention scenarios; moreover, it is crucial to ensure that SRD networks do not impair the radio systems that operate in neighboring licensed spectrum, and vice versa. This paper addresses the previous issues by simulating a building automation application scenario, where 2 channel access mechanisms, namely duty cycling (DC) and carrier sense multiple access (CSMA), are evaluated independently and in coexisting scenarios, and, also, in the presence of a Long‐Term Evolution (LTE) user equipment. The CSMA protocol analysis shows that very high or very low transmission powers decrease its performance, and thus, either this parameter has to be calibrated or the gateways location has to be adjusted; for the DC protocol, its performance is only affected by the number of gateways within the SRD network, which should be as high as possible. Regarding the coexistence of the DC and CSMA schemes, the results show that CSMA‐based SRDs can successfully operate in the presence of a significant number of DC‐based SRDs, whereas the contrary is not true. Lastly, it is proven that an LTE user equipment may harm the SRD network, although this effect can be mitigated by adjusting the SRDs transmission power; furthermore, the SRDs interference on LTE systems is found to be negligible.

Output Power Levels of 4G User Equipment and Implications on Realistic RF EMF Exposure Assessments

The aim of this paper is to present results on output power level distributions of 4G user equipment (UE) using data applications based on a very large number of samples collected over seven days in a long-term evolution (LTE) operating network. The output power data have been obtained through network-based measurements conducted for about 7000 UE connected to 41 LTE radio base stations located in rural, suburban, urban, and indoor environments in Sweden. More than 300 000 power samples were collected. In rural environments, the 95th percentile time-averaged output power values were found to be 2.2% of the maximum available power for LTE UE, while the corresponding values were less than 1% in other environments. The mean output powers in all the environments were found to be less than 1% of the maximum available output power. These values are in line with results obtained for 3G UE despite an almost tenfold increase in the achievable peak data throughput. The findings show that knowledge on realistic power levels is important for accurate assessments of the radio frequency electromagnetic field exposure from mobile communication equipment.

Electromagnetic Compatibility Problems in LTE Mobile Networks 800 MHz Frequency Band

This paper examines the LTE UE (Long-Term Evolution User Equipment) in 800 MHz frequency band (the so-called digital dividend) interference to Short Range Devices (SRD) in the band of 863 MHz–870 MHz. The fundamental objective of this research is to evaluate the probability of interference and influence of LTE UE emission mask in this regards. The study was performed in two methods: theoretical – simulations with SEAMCAT software and practical – measurements to verify gathered results in simulations. The results of this paper characterize the required technical conditions for LTE mobile networks deployment in 800 MHz band. DOI: http://dx.doi.org/10.5755/j01.eee.21.6.13770

Adapting LTE M-2-M Protocol Standard to Fulfil Latency Requirements for IEC 61850 GOOSE Messages

Generic Object Oriented Substation Event (GOOSE) Messages face a great challenge in its communication requirements especially in latency point of view. The appearance of the Long-Term Evolution (LTE) has opened a new way that can be used due to its great performance, compared with previous wireless technologies. In order to use LTE technology within the GOOSE message transfer, several points must be put into consideration, and additional requirements need to be within both LTE User Equipment (UE) side and network side. In this paper, we are going to adapt part of the LTE standards to fulfil the requirements of GOOSE messages which needs latency more than or equal to 20 ms, using an experimental approach. The results show that LTE can satisfy the target requirements of latency within the acceptable Bit Error Rate (BER).

Interference Effects of Low-Power Devices on the UE Throughput of a CR-Based LTE System

Recently, the use of mobile devices has increased, and mobile traffic is growing rapidly. In order to deal with such massive traffic, cognitive radio (CR) is applied to efficiently use limited-spectrum resources. However, there can be multiple communication systems trying to access the white space (unused spectrum), and inevitable interference may occur to cause mutual performance degradation. Therefore, understanding the effects of interference in CR-based systems is crucial to meaningful operations of these systems. In this paper, we consider a long-term evolution (LTE) system using additional spectra by accessing the TV white space, where low-power devices (LPDs) are licensed primary users, in addition to TV broadcasting service providers. We model such a heterogeneous system to analyze the co-existence problem and evaluate the interference effects of LPDs on LTE user equipment (UE) throughput. We then present methods to mitigate the interference effects of LPDs by ‘de-selecting’ some of the UEs to effectively increase the overall sector throughput of the CR-based LTE system.

CoPoMo: a context‐aware power consumption model for LTE user equipment

ABSTRACTIncreasing the battery lifetime of power‐hungry mobile devices has become a major research target for mobile operators. Based on extensive measurement campaigns with the most recent Long Term Evolution (LTE) devices, we introduce a new Markovian power consumption model, which takes into account the chosen system parameters (such as the number of physical resource blocks) as well as the context of a user in terms of radio channel conditions and service characteristics (non‐real‐time vs. real time). One key advancement of this generic model is its stochastic nature, which allows for determining the average power consumption of a device based on usage profiles including location information and service statistics. We have conducted comprehensive system simulations using realistic channel characteristics derived from ray‐tracing analyses and validated the new model. Finally, we show that the proposed context‐aware power consumption model enables quantitative analyses of the trade‐off between network resource allocation and enhanced battery lifetime. © 2013 The Authors. Transactions on Emerging Telecommunications Technologies published by John Wiley & Sons, Ltd.

The Impact of LTE UE on Audio Devices

In this letter, the acoustic noise due to long term evolution (LTE) user equipment (UE) is investigated with various transmitting powers of the LTE UE by using the Monte Carlo method in a practical acoustic noise experiment.

The Impact of LTE UE on Audio Devices

In this letter, the acoustic noise due to long term evolution (LTE) user equipment (UE) is investigated with various transmitting powers of the LTE UE by using the Monte Carlo method in a practical acoustic noise experiment.

Self‐optimization of random access channel in 3rd Generation Partnership Project Long Term Evolution

ABSTRACTThe long term evolution (LTE) is being designed to enhance third generation radio access technologies, and it represents a major step towards high‐performance mobile data networks that are fully optimized for packet‐switched connections. In an initial access, the LTE user equipment executes the random access (RA) procedure while searching for serving base station and initiating services. For a good cell coverage to be obtained, feasible uplink data rate and low delays in, for example, call setup, the optimal random access channel (RACH) performance is essential. Although manual tuning of procedures can be very costly, it is important to design self‐organizing network (SON) algorithms that optimize procedures such as RA. In this paper, a mathematical framework for the RACH modeling in LTE technology is presented on the basis of probability theory and statistics. A self‐optimization algorithm for RACH preamble sequence allocation and preamble split is then examined using the deduced mathematical framework and system‐level simulations. Performance analysis is semi‐analytical: First, RACH performance results are produced using analytical model, and second, outputs are fed into a dynamic LTE network simulator. Results show that the proposed optimization approach clearly improves uplink performance and ensures a certain success rate at the first RA attempt so that shorter handover durations and call setup delays can be achieved. Copyright © 2011 John Wiley & Sons, Ltd.