LTE physical layer Research Papers (original) (raw)

Long range wide area network (LoRaWAN) is one of the most widely used low power wide area (LPWA) network technologies in the unlicensed ISM bands. LoRaWAN adopts chirp spread spectrum (CSS) based physical layer specification which is Semtech's proprietary technology; so the details of the physical layer are not fully disclosed. In this paper, we will investigate the performance of the LoRa interleaver which is one of the main blocks of LoRa physical layer. Specifically, through computer simulations, we will compare a conventional block interleaver and the LoRa interleaver in terms of FER performance in AWGN and Rician fading environments.

LTE is an emerging wireless communication technology to provide high-speed data service for the mobile phones and data terminals. To improve indoor coverage and capacity Femtocells are included in 3GPP since Release 8. There is no common simulation platform is available for performance justification of LTE-Femtocells. LTE-Sim is an object-oriented open source simulator which incorporates a complete protocol stack can be used for simulating two-tier macro-femto scenarios. To the best of our knowledge no paper provides the guideline to perform system level simulation of Femtocell networks. Here, in this paper Femtocells performance is evaluated in multi-Macrocells and multi-Femtocells environment with interference from Microcells and Macrocell users along with the scripting. KEYWORDS Channel quality indicator (CQI), Femto Access Point (FAP), Macro eNodeB (MeNB), Macrocell User Equepment (MUE), Moblity Management Entity(MME), Signal to Interference Plus Noise Ratio(SINR), Physical Layer(PHY)

3rd Generation Partnership Project Long Term Evolution (3GPP-LTE) is focusing towards aggressive frequency reuse i.e. reuse of 1 so that we can get maximum number (all available spectrum) within a cell. Now, the major hindrance is co-channel interference which increases dramatically due to nearby adjacent
co-channel cell and most especially for cell edge users. Traditional frequency reuse concept for
interference management doesn’t provide satisfactory coverage and rate. In this paper, FFR is purposed as
a candidate for interference management and its comparative evaluation over Traditional frequency reuse
on the basis of two parameter metrics viz. probability of coverage and probability of acceptance rate is
done. We observe that FFR has relatively better performance in 3GPP-LTE downlink.

This paper studies control format indicator (CFI) estimation methods in 4G-LTE communication systems. CFI is an essential control signal in LTE, and must be correctly detected at the receiver to avoid degraded system performance. The standard method of CFI detection involves the use of the Maximum Likelihood (ML) estimation criterion. Unfortunately, ML decoding performance relies on accurate channel estimation, and as a consequence may result in poor CFI decoding when channel estimates are poor. To improve CFI detection in severe fading channel conditions, a time-domain decision rule that requires no channel estimation, is proposed. Results show that when compared with the ML approach, the proposed method reduces the probability of CFI estimation error in the form of reduced block error rate.

- by Saheed Adegbite and +1
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- Orthogonal Frequency Division Multiplexing (OFDM), Long Term Evolution (LTE), LTE physical layer, Data Recovery

With the current technology revolution, underwater wireless sensor networks (UWSNs) find several applications such as disaster prevention, water quality monitoring, military surveillance and fish farming. Nevertheless, this kind of networks faces a number of challenges induced by the nature of the underwater environment and its influence on the network physical media. Therefore, the ultimate objective of this paper is to lay down the key aspects of the physical layer of the underwater sensor networks (UWSNs). It discusses issues related to the characteristics and challenges of the underwater communication channel, differences between terrestrial wireless sensor networks and UWSNs, and acoustic propagation models in underwater. The paper also surveys some of the underwater acoustic modems. This study is essential to better understand the challenges of designing UWSNs and alleviate their effects.

- by SHEELA THAVASI
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- Wireless Communications, LTE physical layer

This paper deals with the transmission of group-oriented services, considered as the main value-added for the future 4G broadband wireless systems. In this scenario, the design of proper resource allocation strategies is a key issue in order to offer high quality services to involved users and to efficiently exploit the available radio resources. In this paper we extend the works existing in literature by evaluating the impact of frequency selectivity on the performance in terms of spectral efficiency achieved when group-oriented services are provided in Long Term Evolution (LTE) and LTE-Advanced (LTE-A) systems. We conducted exhaustive simulation campaigns in order to define the scenarios that could benefit of the exploitation of frequency selectivity in multicast resource allocation. We investigated single- and multi-group scenarios with different application profiles, such as real time video flows, and we considered several deployment cases addressing different channel bandwidth and user configurations.

Multicast services over Long Term Evolution (LTE) have recently attracted the interest of the research community. Particular attention has been put on handling fairness requirements of multicast users and experienced channel quality. Conventional Multicast Scheme (CMS), Opportunistic Multicast Scheme (OMS), and multicast subgroup formation are the principal policies adopted to address this research issue. Little attention has been given so far to multicarrier systems like LTE-Advanced although the need for solutions appropriate to this system is strongly felt. In this paper we design radio resource management policies for the efficient delivery of multicast services in multicarrier LTE-Advanced systems and show how the relation between fairness and system efficiency can be controlled. Concerning the system resource management, game theoretic bargaining solutions are considered to best model fairness and efficiency (expressed in terms of throughput).

- by Massimo Condoluci
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- Wireless Communications, Long Term Evolution (LTE), WiMAX/LTE/LTE-A, LTE
- by Ahmed Sultan
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- IEEE 802.16 (WiMAX), Synchronization, WiMAX/LTE/LTE-A, LTE physical layer

Long Term Evolution (LTE) is considered the most promising cellular system able to support the growing demand of multicast services (e.g., IPTV, video streaming) over mobile terminals. The design of effective strategies for the management of these applications is still an open issue, especially in scenarios where several multicast streams are simultaneously transmitted in a cell. In this paper we propose different resource allocation policies for the delivery of multicast scalable video flows. Such policies efficiently exploit the multi-user diversity and the frequency selectivity in order to match the requirements of both users and providers. The performance of the proposed strategies is analyzed through simulations by evaluating different cell deployment and user load environments and by focusing on spectral efficiency, throughput, fairness, and amount of resources needed for multicast service delivery. The last parameter is important in practical scenarios where multicast services share the available resources with other flows, e.g., unicast services.

- by Massimo Condoluci
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- Long Term Evolution (LTE), 3G and 4G technologies, WiMAX/LTE/LTE-A, LTE

"This paper addresses the design of an adaptive resource allocation policy for the efficient delivery of multicast services in Long Term Evolution (LTE) systems.
The proposed approach overcomes the intrinsic inefficiencies of Conventional Multicast Scheme (CMS) related to the different channel quality experienced by the involved users.
The basic idea is to split any multicast group into subgroups and apply subgroup-based adaptive modulation and coding schemes, which enable a more efficient exploitation of multi-user diversity.
The distribution of users into subgroups is determined by the solution of an optimization problem, aiming to improve the network throughput while guaranteeing fairness among multicast members."

In this paper, we address the definition of a low-complexity subgroup formation algorithm for multicast data delivery in Long Term Evolution (LTE) networks. With this aim, we extend the subgroup merging scheme (SMS), designed for generic Orthogonal Frequency Division Multiple Access (OFDMA) systems, by proposing two low-complexity subgroup formation schemes, named L-SMS and L-eSMS. Such schemes are tailored to exploit the great potentialities of LTE systems. Specifically, L-SMS is proposed in order to improve the scalability of SMS by handling a more efficient subgroup formation scheme with a computational cost which does not depend on the multicast group size. The L-eSMS also improves the resource assignment phase with the aim to achieve better near-optimal performance compared to L-SMS. Through simulations, we evaluated the effectiveness of the proposed schemes in different cell deployment and multicast configuration scenarios. The achieved results underlined that the proposed L-eSMS is well designed in order to guarantee performance close to the optimal one.

- by Massimo Condoluci
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- Wireless Communications, Scheduling, Long Term Evolution (LTE), WiMAX/LTE/LTE-A
- by Mahmoud Hamed
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- Engineering, IEEE 802.16 (WiMAX), Synchronization, WiMAX/LTE/LTE-A

To reduce the occurrence of high peak-to-average power ratio (PAPR), this paper introduces prolate-binary sequences, and their application in orthogonal frequency division multiplexing (OFDM) systems that implement selected mapping (SLM). Through computer simulation, it is shown that the proposed prolate-binary sequences offer combined improved PAPR reduction performance, and reduced computational complexity compared with Riemann-binary sequences.

- by Saheed Adegbite and +1
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- Computational Complexity, Orthogonal Frequency Division Multiplexing (OFDM), Long Term Evolution (LTE), Ofdm Systems
- by ana moz
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- Market Research, Marketing Research, Long Term Evolution (LTE), WiMAX/LTE/LTE-A

Initial downlink synchronization for orthogonal frequency division multiple access ( OFDMA )
network access involves timing and frequency synchronization. The frequency offset is produced
by oscillator drifts and time-varying Doppler shifts. In mobile WiMAX 802.16e carrier frequency
offset (CFO) can be divided into: integral carrier frequency offset (ICFO) and fractional carrier frequency
offset (FCFO). There are mainly three methods for CFO estimation: data-aided method,
blind and semi-blind. This paper is based on the semi-blind method presented in ”Joint detection
of integral carrier frequency offset and preamble index in OFDMA WiMAX downlink synchronization”,
IEEE, 2007 , see [2]. We simplify the algorithm presented in that paper by (a) using an
adder-subtractor instead of using squares to estimate power and (b) by using a XNOR instead of
complex multiplier; thereby reducing hardware gates by a factor of 676. Simulation results show
only a slight degradation in performance with a considerable reduction in complexity.

- by Ahmed Ahmedin
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- IEEE 802.16 (WiMAX), Synchronization, WiMAX/LTE/LTE-A, GSM, WiMAX, LTE