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Showing papers by "Preben Mogensen published in 2014"


Proceedings ArticleDOI
01 Dec 2014
TL;DR: The effective bandwidth and the effective capacity theory are used as analytical framework for calculating the maximum achievable rate for a given latency and reliability constraint in a cellular network.
Abstract: We address the fundamental tradeoffs among latency, reliability and throughput in a cellular network. The most important elements influencing the KPIs in a 4G network are identified, and the inter-relationships among them is discussed. We use the effective bandwidth and the effective capacity theory as analytical framework for calculating the maximum achievable rate for a given latency and reliability constraint. The analysis is conducted in a simplified LTE network, providing baseline — yet powerful — insight of the main tradeoffs. Guidelines to extend the theory to more complex systems are also presented, including a semi-analytical approach for cases with intractable channel and traffic models. We also discuss the use of system-level simulations to explore the limits of LTE networks. Based on our findings, we give some recommendations for the imminent 5G technology design phase, in which latency and reliability will be two of the principal KPIs.

121 citations


Proceedings ArticleDOI
10 Jun 2014
TL;DR: A description on how the achieved short TDD latency can be utilized to enable remarkably low energy consumption is provided and a numerical analysis comparing the battery life time of the suggested 5G TDD air interface and LTE is provided, showing remarkable gains for the 5G air interface concept.
Abstract: The target for a new 5G radio access technology is to support multi-Gbps and ms latency connectivity simultaneously at noticeably lower energy consumption and cost compared to the existing 4G technologies, such as LTE-Advanced. Extremely short air interface latency is required to achieve these requirements in a TDD-based local area network. In this paper, we discuss how the required short TDD latency can be achieved and further utilized in 5G physical air interface. First, we investigate the enablers and limits of TDD latency by analyzing the performance of OFDM in different channel environments and discussing on the consequent frame length limits. We then provide a description on how the achieved short TDD latency can further be utilized to enable remarkably low energy consumption. A numerical analysis comparing the battery life time of the suggested 5G TDD air interface and LTE is provided, showing remarkable gains for the 5G air interface concept.

91 citations


Journal Article
TL;DR: A Long Term Evolution (LTE) smartphone power model is proposed, which is primarily intended as an instrument for the network engineers in deciding on optimal network settings, but could also be beneficial for chipset manufacturers to identify main power consumers when taking actual operating characteristics into account.
Abstract: Smartphone users struggle with short battery life, and this affects their device satisfaction level and usage of the network. To evaluate how chipset manufacturers and mobile network operators can improve the battery life, we propose a Long Term Evolution (LTE) smartphone power model. The idea is to provide a model that makes it possible to evaluate the effect of different terminal and network settings to the overall user equipment energy consumption. It is primarily intended as an instrument for the network engineers in deciding on optimal network settings, but could also be beneficial for chipset manufacturers to identify main power consumers when taking actual operating characteristics into account. The smartphone power consumption model includes the main power consumers in the cellular subsystem as a function of receive and transmit power and data rate, and is fitted to empirical power consumption measurements made on state-of-the-art LTE smartphones. Discontinuous Reception (DRX) sleep mode is also modeled, because it is one of the most effective methods to improve smartphone battery life.

85 citations


Proceedings ArticleDOI
18 May 2014
TL;DR: Fundamental features such as optimized short frame structure, multi-antenna technologies, interference rejection, rank adaptation and dynamic scheduling of uplink/downlink transmission are discussed, along with the design of a novel flexible waveform and energy-saving enablers.
Abstract: Ultra-dense small cells are foreseen to play an essential role in the 5th generation (5G) of mobile radio access technology, which will be operating over different bands with respect to established systems. The natural step for exploring new spectrum is to look into the centimeter-wave bands as well as exploring millimeter-wave bands. This paper presents our vision on the technology components for a 5G centimeter-wave concept for ultra-dense small cells. Fundamental features such as optimized short frame structure, multi-antenna technologies, interference rejection, rank adaptation and dynamic scheduling of uplink/downlink transmission are discussed, along with the design of a novel flexible waveform and energy-saving enablers.

80 citations


Proceedings ArticleDOI
18 May 2014
TL;DR: Significant focus is given to the novel zero-tail paradigm, which allows boosting the OFDM flexibility while circumventing demerits such as poor spectral containment and sensitivity to hardware impairments.
Abstract: The ideal radio waveform for an upcoming 5th Generation (5G) radio access technology should cope with a set of requirements such as limited complexity, good time/frequency localization and simple extension to multi-antenna technologies. This paper discusses the suitability of Orthogonal Frequency Division Multiplexing (OFDM) and its recently proposed enhancements as 5G waveforms, mainly focusing on their capability to cope with our requirements. Significant focus is given to the novel zero-tail paradigm, which allows boosting the OFDM flexibility while circumventing demerits such as poor spectral containment and sensitivity to hardware impairments.

69 citations


Proceedings ArticleDOI
01 Dec 2014
TL;DR: This work highlights deployment and implementation strategies for massive MIMO in the context of 5G indoor small cell scenarios and indicates how to integrate large-scale arrays in future 5G networks.
Abstract: Massive MIMO has emerged as one technology enabler for the next generation mobile communications 5G. The gains promised by massive MIMO are augured to overcome the capacity crunch in today's mobile networks and to pave the way for the ambitious targets of 5G. The challenge to realize massive MIMO for 5G is a successful and cost-efficient integration in the overall network concept. This work highlights deployment and implementation strategies for massive MIMO in the context of 5G indoor small cell scenarios. Different massive MIMO deployment scenarios are analyzed for a standard 3GPP indoor office scenario. In particular stand-alone MIMO at a single location, distributed MIMO without cooperation and network MIMO with full cooperation are investigated for varying array configurations. For the performance analysis of the different MIMO configurations the ratio of total transmit antennas to spatial streams is varied stepwise from equality to a factor of ten. For implementation of massive MIMO in 5G networks trends in beamforming techniques, mutually coupled subarrays, over the calibration procedure and estimated ADC performance in 2020 time-frame are discussed. Based on the debate the paper indicates how to integrate large-scale arrays in future 5G networks.

68 citations


Proceedings ArticleDOI
17 Sep 2014
TL;DR: A measurement-based analysis of the outdoor-to-indoor attenuation experienced in several modern constructions compared to an old building shows a material dependent and a frequency dependent attenuation, with an average increase of 20-25 dB in modern construction compared to the old construction.
Abstract: Energy-efficient buildings are gaining momentum in order to comply with the new energy regulations. Especially in northern cold countries, thick reinforced walls and energyefficient windows composed of several layers of glass plus metal coating are becoming the de facto elements in modern building constructions, and it has been noticed that they can impact heavily on radio signal propagation. This paper presents a measurement-based analysis of the outdoor-to-indoor attenuation experienced in several modern constructions compared to an old building. The measurements are performed for frequencies from 800 MHz to 18 GHz with the aim of identifying the frequency dependence and the impact of the new materials on not only the cellular frequency bands used today (mainly below 3 GHz), but also the potential future bands (above 3 GHz). The results show a material dependent and a frequency dependent attenuation, with an average increase of 20-25 dB in modern constructions compared to the old construction, which presents a low and almost constant attenuation below 10 dB. The different measurement results and observations presented along the paper are useful for future radio network planning considerations.

67 citations


Proceedings ArticleDOI
04 Dec 2014
TL;DR: The comparison between the measured and predicted results show good accuracy is obtained when a simplified RT model is used, suggesting that fast and simple ray tracers will be able to correctly predict the propagation characteristics at mmWave bands.
Abstract: In the summer of 2013, a wideband propagation measurement campaign using rotating directional antennas at 73 GHz was conducted at the New York University (NYU) campus, in order to collect extensive field measurements for use in a millimeter wave (mmWave) E-band statistical channel model. While the measurement campaign provided over 50 Gigabytes of wideband power delay profiles and angular responses [1], [2], the time and labor intensive measurements were based on only 5 transmitter (Tx) locations and 27 receiver (Rx) locations, making up a total of 74 Tx-Rx link combinations. To help generalize the measurements for immediate model development and eventual site planning, this paper presents an empirical ray-tracing model, with the goal of finding a suitable approach such that ray-tracing (RT) can fill in the gaps of the measurements. Here, we use the measured data to investigate the prediction capability of an empirical RT model, in which the 3D model of New York City (including the building structures and interaction losses) are greatly simplified. The comparison between the measured and predicted results show good accuracy is obtained when a simplified RT model is used, suggesting that fast and simple ray tracers will be able to correctly predict the propagation characteristics at mmWave bands.

43 citations


Proceedings ArticleDOI
04 Dec 2014
TL;DR: The benefits of ZT DFT-s-OFDM in terms of coexistence among devices operating over adjacent frequency chunks, possibility of adopting unified radio numerology among different cells, reduced latency and support of agile link direction switching are addressed.
Abstract: Zero-tail Discrete Fourier Transform -spread OFDM (ZT DFT-s-OFDM) modulation allows to dynamically cope with the delay spread of the multipath channel, thus avoiding the limitations of hard-coded Cyclic Prefix (CP). In this paper, we discuss the potential of ZT DFT-s-OFDM modulation for the envisioned 5 th generation (5G) radio access technology, characterized by an ultra-dense deployment of small cells and the support of novel paradigms such as Device-to-Device (D2D). We address the benefits of ZT DFT-s-OFDM in terms of coexistence among devices operating over adjacent frequency chunks, possi- bility of adopting unified radio numerology among different cells, reduced latency and support of agile link direction switching. The robustness of ZT DFT-s-OFDM towards non-idealities such as phase noise and non-linear power amplifier is also discussed.

40 citations


Proceedings ArticleDOI
04 Dec 2014
TL;DR: A distributed algorithm to deal with sudden traffic imbalances between downlink (DL) and uplink (UL) in the new 5G system is proposed and can approximately double the session throughput and halve the packet delay in a large number of cases.
Abstract: 5th Generation (5G) small cells are expected to satisfy the increasing demand for wireless data traffic. In the presence of large scale dense and randomly deployed cells, autonomous and distributed configuration mechanisms are highly desirable. However, small cells typically serve a small number of users, such that sudden traffic imbalances between downlink (DL) and uplink (UL) are expected in the new 5G system. We exploit the flexibility of time-division duplex (TDD) to deal with such imbalances by adapting swiftly to instantaneously varying traffic needs. In this paper we propose a distributed algorithm to deal with these varying traffic requirements. We also exploit the availability of interference rejection capable receivers. Simulation results show that in the presence of the aforementioned features, we can approximately double the session throughput and halve the packet delay in a large number of cases.

26 citations


Proceedings ArticleDOI
18 May 2014
TL;DR: Results show that the inter-cell interference depends on the small cell deployment in the urban environment (e.g. streets and squares) and on the network load condition, and that the interference coordination enhances both average and coverage user throughput in case of high network Load condition.
Abstract: The deployment of low-power small cells is envisaged as the main driver to accommodate the mobile broadband traffic growth in cellular networks. Depending on the spatial distribution of the user traffic, a densification of the small cells may be required in confined areas. However, deploying more and more cells in given areas may imply an increase of the inter-cell interference among the small cells. This study aims at investigating if the inter-cell interference among outdoor small cells may represent an impairment to the user experience, and evaluates if and in what conditions the interference coordination is worthwhile compared to the universal frequency reuse. Results show that the inter-cell interference depends on the small cell deployment in the urban environment (e.g. streets and squares) and on the network load condition. In case of deployment along urban streets, the inter-cell interference does not affect the user throughput and no interference coordination is required. On the other hand, if deployed in open areas (e.g. city squares) the interference coordination enhances both average and coverage user throughput in case of high network load condition.

Proceedings ArticleDOI
06 Apr 2014
TL;DR: Basic stochastic geometry models are relied on to analytically evaluate the performance of interference cancellation receivers in a local area network scenario, under `realistic' rate-constraints on the decodability of the interference signal.
Abstract: The ideal successive interference cancellation paradigm helps to achieve the capacity of some multiuser channels, such as the Gaussian multiple access and broadcast channels. However, its performance is much more modest under realistic constraint on the decodability of the interference signal. In this paper, we rely on basic stochastic geometry models to analytically evaluate the performance of interference cancellation receivers in a local area network scenario, under `realistic' rate-constraints on the decodability of the interference signal. Analytical findings are validated by extensive Monte Carlo experiments. Alongside, complementary system level simulations results are presented to demonstrate the performance in a `practical'-like system. Our findings explicitly quantify how the gains from interference cancellation techniques depend on the spatial density of the active interferers in the network, and their respective data rates. The findings further highlight the importance of properly dimensioning the system in order to fully benefit from such interference cancellation techniques.

Proceedings ArticleDOI
18 May 2014
TL;DR: System level simulation results confirm that a realistic MMSE-IRC receiver can achieve throughput gains close to ideal, provided a reasonably high resolution Analog-to-Digital Converter (ADC) as well as a supportive radio frame format design are used.
Abstract: The usage of Minimum Mean Square Error - Interference Rejection Combining (MMSE-IRC) receivers is expected to be a significant performance booster in the ultra-dense deployment of small cells envisioned by an upcoming 5th generation (5G) Radio Access Technology (RAT). However, hardware limitations of the radio- frequency front-end and poor covariance matrix estimation may severely compromise its ideal gains. In this paper, we evaluate the network performance of MMSE-IRC receivers by including the effects of the receiver imperfections as well as realistic covariance matrix estimates. System level simulation results confirm that a realistic MMSE- IRC receiver can achieve throughput gains close to ideal, provided a reasonably high resolution Analog-to-Digital Converter (ADC) as well as a supportive radio frame format design are used.

Journal ArticleDOI
TL;DR: Results show that the proposed optimization algorithm provides good flexibility to support different policies by simply adjusting some weighting factors, and the Q-Learning algorithm is shown as an effective solution to adapt the network to context variations, such as those produced in the user spatial distribution.

Proceedings ArticleDOI
18 May 2014
TL;DR: This paper analyzes established and emerging technological solutions for features such as waveform, frame structure, duplexing and multiple antenna transmission from an EE perspective and gives general recommendations for an energy efficient 5G design in the context of a previously proposed RAT concept.
Abstract: Research on fifth generation (5G) radio access technology (RAT) is ramping up, with the goal of significantly improving user data rates and latency compared to previous RAT generations. While energy efficiency (EE) of the user equipment (UE) was not a key optimization parameter for the current wireless standards, it is anticipated to become a distinguishing factor for 5G. In this paper, we analyze established and emerging technological solutions for features such as waveform, frame structure, duplexing and multiple antenna transmission from an EE perspective. Our contribution is to identify and discuss the features' pros and cons in achieving high performance in terms of data rate and/or latency while limiting their effect on the UE power consumption. Based on the discussion we give general recommendations for an energy efficient 5G design in the context of a previously proposed RAT concept.

Proceedings ArticleDOI
18 May 2014
TL;DR: This paper proposes an efficient and computationally effective rank adaptation algorithm based on an estimate of the mean signal-to-interference-plus- noise ratio (SINR) at an IRC receiver, and uses results from random matrix theory to derive the expression for the mean post-IRC SINR in the presence of interferers with unequal powers.
Abstract: Multiple transmit and receive antennas introduce additional degrees of freedom, which can be used to increase the number of spatial channels between a transmitter-receiver pair. Alternately, the additional degrees of freedom can be used to improve the interference resilience property with the help of linear interference rejection combining (IRC) receivers. Typically, rank adaptation algorithms are aimed at balancing the trade-off between increasing the spatial gain, and improving the interference resilience property. In this paper, we propose an efficient and computationally effective rank adaptation algorithm based on an estimate of the mean signal-to-interference-plus- noise ratio (SINR) at an IRC receiver; wherein, we use results from random matrix theory to derive the expression for the mean post-IRC SINR in the presence of interferers with unequal powers. The performance of the proposed algorithm is analysed through system level simulations. The results are found to be comparable to the optimum performance, and match closely to that of a more complex existing rank adaptation method.

Proceedings ArticleDOI
13 Jun 2014
TL;DR: Simulation results confirm the capability of HARQ of improving the final throughput and solving outage problems, with limited impact on the end delay, and its performance is evaluated for two different scheduling options.
Abstract: A new 5th generation (5G) radio access technology is expected to cope with an estimated factor of ∼x1000 growth in mobile data traffic in the upcoming years. Such system will be optimized for a massive uncoordinated deployment of small cells, where autonomous operation of the individual nodes may bring unpredictable and fast varying link quality. In this paper, Hybrid Automatic Repeat Request (HARQ) is studied as a solution to cope with such unpredictability. An operational mode of HARQ for our 5G system definition is proposed, and its performance is evaluated for two different scheduling options. Simulation results confirm the capability of HARQ of improving the final throughput and solving outage problems, with limited impact on the end delay.

Proceedings ArticleDOI
04 Dec 2014
TL;DR: This work examines how the activation and use of CA (10 + 10 MHz) affects the UE current consumption with different traffic profiles such as FTP or web browsing and presents the first publicly available current consumption measurements on a commercial CA-capable UE.
Abstract: Carrier Aggregation (CA) is introduced in LTE release 10 to improve data rates by allowing the User Equipment (UE) to receive data on more than one LTE carrier. The related increased complexity is expected to affect the UE current consumption, but yet no empirical evaluation has been published on this topic. Currently there are only theoretical expansions of LTE release 8 power models available, but this article presents the first publicly available current consumption measurements on a commercial CA-capable UE. In this work it is examined how the activation and use of CA (10 + 10 MHz) affects the UE current consumption with different traffic profiles such as FTP or web browsing. For a large FTP download the average CA current consumption is reduced 13 % compared to single-carrier 10 MHz due to increased data rate and extended idle time, which allows the UE to enter a low-current sleep mode. For small data bursts, such as keep-alive messages, configuring CA results in 17 mA average current increase during RRC connected state inactivity periods. Depending on the UE background activity, this could translate into 3 % to 8 % reduction of the UE’s stand-by battery life.

Proceedings ArticleDOI
01 Jan 2014
TL;DR: This paper considers a small-cell/local area cellular system and proposes a simple and distributed interference-aware rank adaptation algorithm aimed at maximizing the system sum throughput.
Abstract: Typically, rank adaptation (RA) algorithms are aimed at balancing the trade-off between increasing the spatial gain and improving the interference resilience property. In this paper, we consider a small-cell/local area cellular system and propose a simple and distributed interference-aware rank adaptation algorithm aimed at maximizing the system sum throughput. The performance of the proposed algorithm is numerically evaluated in terms of the system sum throughput. Simulation results show that the proposed algorithm results in close to optimum throughput performance, and can provide up to 40% throughput gain over interference-unaware RA schemes.


Proceedings ArticleDOI
18 May 2014
TL;DR: Simulation results show the effectiveness of an ID-based approach in limiting the asynchronous interference, however at the expense of a potential high number of timing reconfigurations, and an hybrid solution is shown to be an effective trade-off between the two former approaches.
Abstract: Time synchronization in a large network of small cells enables efficient interference management as well as advanced transmission techniques which can boost the network throughput. In this paper, we focus on the distributed initial synchronization problem and propose different solutions aiming at reducing the residual asynchronous interference while limiting the number of large timing reconfigurations at each node. Simulation results show the effectiveness of an ID-based approach in limiting the asynchronous interference, however at the expense of a potential high number of timing reconfigurations. A pathlossbased solution limits such reconfigurations but also leads to a higher residual interference than the ID-based solution. An hybrid solution is shown to be an effective trade-off between the two former approaches.

Proceedings ArticleDOI
01 Jan 2014
TL;DR: System-level simulation results show that MRP outperforms FRP in both low and high traffic load conditions, with 44% and 49% outage throughput gains in each case, respectively.
Abstract: In this paper, we propose Maximum Rank Planning (MRP) as a novel inter-cell interference management technique for the ultra-dense uncoordinated deployment of small cells targeted by 5th Generation (5G) networks. Rather than operating in the frequency domain as the conventional Frequency Reuse Planning (FRP) technique, MRP acts by reducing the number of Multiple Input Multiple Output (MIMO) spatial multiplexing streams. This reduction leads to an increased probability that the Interference Rejection Combining (IRC) receiver will have sufficient degrees-of-freedom to reject the strongest interferers. System-level simulation results show that MRP outperforms FRP in both low and high traffic load conditions, with 44% and 49% outage throughput gains in each case, respectively.

Proceedings ArticleDOI
04 Dec 2014
TL;DR: Measurements show that the downlink and uplink data rates of the WiFi solution are significantly higher than femto data rates, and latency results show that WiFi outperforms the femto solution.
Abstract: In this paper HSPA Release 6 femto and IEEE 802.11g WiFi indoor data solutions are investigated from an end user perspective. Femto and WiFi access points are deployed at typical locations in an urban environment and end user performance is measured. Three key performance indicators (KPI) were defined - downlink and uplink user data rates, latency and mobile power consumption. These three KPIs are of high importance when choosing an indoor data solution. Our measurements show that the downlink and uplink data rates of the WiFi solution are significantly higher than femto data ra tes. Similarly, latency results show that WiFi outperforms the femto solution. Especially, the radio resource control (RRC) connection set-up time increases the latency for the femto. In terms of idle power consumption the best results are obtained when the mobile camps on the femto. Whereas, WiFi performs best in all active mode power consumption measurements. Based on our KPIs, the preferred indoor data solution today is WiFi. The deciding factor is the combined latency and power performance of the WiFi, where WiFi outperforms the femto.

Proceedings ArticleDOI
01 Dec 2014
TL;DR: This paper proposes a paradigm shift for the Evolved Packet Core for the future 5G system, leveraging on the economy of scale of software-based ICT technologies, namely Software Defined Networking and cloud computing, to propose a hierarchically cloudified mobile network.
Abstract: A massive traffic increase is foreseen in the near future in mobile networks. Such data storm is expected to pose new challenging requirements to the existing mobile network architecture, since the traffic will be generated by a wide set of applications running on an increasingly high number of mobile devices and sensors. In this paper we propose a paradigm shift for the Evolved Packet Core for the future 5G system. By leveraging on the economy of scale of software-based ICT technologies, namely Software Defined Networking and cloud computing, we propose a hierarchically cloudified mobile network. In particular, in this paper we focus on the mobility aspects within such new architecture, proposing low latency Layer 2 solutions for the Access Network, while exploiting aggregating Layer 3 mobility functionalities in the regional and national clouds.

Proceedings ArticleDOI
01 Nov 2014
TL;DR: Experimental results demonstrate the possibility of synchronizing the timing of the multiple nodes with a few μs precision, despite of the occurrencies of beacon losses.
Abstract: Network synchronization is a fundamental enabler of interference mitigation techniques that are required in ultradense deployment of small cells as targeted by upcoming 5th Generation (5G) wireless system. In this paper, we experimentally evaluate the possibility of acheiving in a distributed manner (i.e. without any external high precision reference clocks) a tight time alignment in a network of small cells. We are considering a software defined radio (SDR) network of 8 nodes, where each node adopts the Universal Software Radio Peripheral N200 (USRP N200) radio boards by Ettus Research, and the ASGARD software platform. Experimental results demonstrate the possibility of synchronizing the timing of the multiple nodes with a few μs precision, despite of the occurrencies of beacon losses.

Proceedings ArticleDOI
04 Dec 2014
TL;DR: The results indicate that, although the deployment of outdoor cells is very important to increase the capacity of the current networks, the expansion with indoor small cells is essential in order to provide coverage and capacity for the future wireless service consumers, specially those located in the high rise buildings.
Abstract: This paper studies the capability of Long-Term Evolution-Advanced (LTE-A) together with WiFi 802.11ac to accommodate the traffic growths of 80x, 500x and 1000x in a high rise building scenario. It provides a guideline on the configuration of the spectrum and the best deployment options for the evolution of the heterogeneous network in order to enhance the capacity for the coming years. The results indicate that, although the deployment of outdoor cells is very important to increase the capacity of the current networks, the expansion with indoor small cells is essential in order to provide coverage and capacity for the future wireless service consumers, specially those located in the high rise buildings.

Proceedings ArticleDOI
06 Apr 2014
TL;DR: Evaluating different mechanisms for providing Inter-Frequency (IF) Load Balancing (LB) in multi-layer heterogeneous deployments shows that although quality-based handoff procedures can act as a passive TS mechanism, they are costly in handovers and measurements gaps.
Abstract: This paper aims at evaluating different mechanisms for providing Inter-Frequency (IF) Load Balancing (LB) in multi-layer heterogeneous deployments. More specifically, the performance of IF mobility management based on signal quality measurements is compared against a load-dependent Traffic Steering (TS) framework that triggers IF mobility events only if load imbalance is detected. To evaluate the joint interaction of the aforementioned schemes with more advanced LB features, system level simulations have been conducted with and without Carrier Aggregation (CA) capable users. Results have shown that although quality-based handoff procedures can act as a passive TS mechanism, they are costly in handovers and measurements gaps. The developed TS scheme utilizes cell neighbor measurements more efficiently, achieving significant handover reduction. Finally, CA makes the proposed framework even more attractive, since its careful parameterization becomes less relevant and load imbalances can be tackled by the packet scheduler as well.

Proceedings ArticleDOI
18 May 2014
TL;DR: A laboratory emulation setup for evaluation of Long Term Evolution (LTE) mobility performance in a co-channel heterogeneous network (HetNet) and how it varies depending on load conditions and the configuration of UE reporting events is introduced.
Abstract: In this paper we introduce a laboratory emulation setup for evaluation of Long Term Evolution (LTE) mobility performance in a co-channel heterogeneous network (HetNet). The setup consists of two eNodeB emulators, signal faders and release 9 LTE User Equipment (UE). It is shown how the LTE HetNet mobility performance varies depending on load conditions and the configuration of UE reporting events. Pico cell outbound handover to the macro cell are found to be particular challenging, especially for higher UE speeds. Finally, we discuss the prospects of the emulation setup and how it can be exploited to conduct further experiments towards gaining additional understanding of HetNet mobility performance for LTE UEs.

Proceedings ArticleDOI
18 May 2014
TL;DR: This paper adopts an experimental procedure for acquiring almost 1000 different radio link conditions between the nodes of a relevant wireless indoor network scenario and used them as input to a system level simulator in order to evaluate the performance of a local area decentralized ICIC scheme.
Abstract: The characteristics of the deployment scenario are fundamental elements in the performance evaluation of wireless networks inter-cell interference coordination (ICIC) schemes. The statistical validation of such concepts is typically achieved by means of system-level simulation campaigns where regular reference scenarios and stochastic channel models are employed. It is an important next step to verify that the trends observed in the reference scenarios compare equally well in more practical deployments. For such comparison, it is required to evaluate an extensive set of link conditions, reflecting the many possible configurations that can be experienced in a practical scenario. In this paper we adopt an experimental procedure, using a software defined radio testbed, for acquiring almost 1000 different radio link conditions between the nodes of a relevant wireless indoor network scenario. The acquired measurements, were used as input to a system level simulator in order to evaluate the performance of a local area decentralized ICIC scheme. The obtained performance results highlight the contribution of the selected scheme and provide a new insight for the validation of the related simulation-based studies, previously published in literature.