Book•
4G: LTE/LTE-Advanced for Mobile Broadband
21 Mar 2011-
TL;DR: In this article, the authors focus on LTE with full updates including LTE-Advanced to provide a complete picture of the LTE system, including the physical layer, access procedures, broadcast, relaying, spectrum and RF characteristics, and system performance.
Abstract: Based on the bestseller "3G Evolution - HSPA and LTE for mobile broadband" and reflecting the ongoing success of LTE throughout the world, this book focuses on LTE with full updates including LTE-Advanced to provide a complete picture of the LTE system. Overview and detailed explanations are given for the latest LTE standards for radio interface architecture, the physical layer, access procedures, broadcast, relaying, spectrum and RF characteristics, and system performance. Key technologies presented include multi-carrier transmission, advanced single-carrier transmission, advanced receivers, OFDM, MIMO and adaptive antenna solutions, advanced radio resource management and protocols, and different radio network architectures. Their role and use in the context of mobile broadband access in general is explained. Both a high-level overview and more detailed step-by-step explanations of the LTE/LTE-Advanced implementation are given. An overview of other related systems such as GSM/EDGE, HSPA, CDMA2000, and WIMAX is also provided. This book is a 'must-have' resource for engineers and other professionals in the telecommunications industry, working with cellular or wireless broadband technologies, giving an understanding of how to utilize the new technology in order to stay ahead of the competition. The authors of the book all work at Ericsson Research and have been deeply involved in 3G and 4G development and standardisation since the early days of 3G research. They are leading experts in the field and are today still actively contributing to the standardisation of LTE within 3GPP. Includes full details of the latest additions to the LTE Radio Access standards and technologies up to and including 3GPP Release 10Clear explanations of the role of the underlying technologies for LTE, including OFDM and MIMO Full coverage of LTE-Advanced, including LTE carrier aggregation, extended multi-antenna transmission, relaying functionality and heterogeneous deploymentsLTE radio interface architecture, physical layer, access procedures, MBMS, RF characteristics and system performance covered in detail
Citations
More filters
Dissertation•
21 Jul 2017
TL;DR: One of the main contributions of this PhD Thesis is the creation of a smart mobility plan based on fuzzy logic and vehicular communications which is able to determine when a traffic jam occurs in the city, allowing vehicles to adopt alternative routes.
Abstract: RESUMEN (en Ingles)
In recent years, the society is experiencing a great technological revolution which, together with the emergence of wireless technologies and smaller devices, is leading to a great impulse in the creation of new services and applications for citizens. Within this revolution, communications networks have served to interconnect people and devices by forging the current Network Society.
A few years ago, the term Smart City appeared. This concept is based on the proposal of new solutions that provide a city with services designed to improve the lives of citizens and favor the development of a city as a whole. In this area, the Intelligent Transport Systems (ITS) have led to an important rise in the development of new technological proposals applied to the world of transport. Within the ITS, the concept of vehicular networks arose (Vehicular Ad-hoc NETworks - VANET). This type of wireless network is capable of communicating vehicles and infrastructure to provide certain services. At present, such networks are in the sights of technological developments due to the expected number of applications and services that can contribute to the world of driving and society in general.
Simulation is a fundamental tool in the study of the behavior of vehicular networks. In view of the high cost of devices that implement dedicated standards for VANET networks, such as IEEE 802.11p, and the road safety risks involved in the deployment of this type of network, simulation becomes essential for the creation and implementation of new solutions. In this sense, this PhD Thesis performs a thorough review of the existing tools used for the simulation of vehicular networks, proposing a case study applied on the exchange of video in this type of environments. As a result, the integration of three simulators to carry out the video exchange is presented, obtaining an acceptable rate of information transmitted by the vehicles and evaluating the feasibility of the proposal.
The mobility is one of the most important aspects in the deployment of vehicular networks. In this sense, one of the main contributions of this PhD Thesis is the creation of a smart mobility plan based on fuzzy logic and vehicular communications which is able to determine when a traffic jam occurs in the city, allowing vehicles to adopt alternative routes. The results of this proposal achieve a reduction of pollutant emissions of up to 12.27%, leading to an improvement of environmental sustainability in the city through the adoption by vehicles of alternative routes in order to reach their destination.
One of the problems posed by simulated studies is the achievement of truthful results. Due to the simulation, erroneous conclusions can be drawn which require a real deployment to confirm that the data obtained in the simulation are correct and representative. Considering the high cost of this type of deployment, one of the objectives of the PhD Thesis was to carry out a real deployment through the use of technologies accessible to citizens. At this point, it was decided to develop an application that uses Wi-Fi Direct (technology available in the majority of current smartphones), to detect possible traffic jams or retentions in the city and capable of communicating with other devices. The actual tests were carried out with two vehicles that incorporated the application. The results of this type of evaluation were satisfactory in terms of the existing possibility of carrying out vehicular communications using technologies accessible to the general public, giving a clear example of a system that can help improve mobility in the city.
Once the actual study was carried out, the problem arose about the usability of devices on vehicles that provide information services in the vehicular networks. For this purpose, this PhD Thesis proposes the evaluation of two types of systems that provide information to the driver. First, systems with HDD (Head-Down Display) type screens, which are devices with opaque (conventional) screens, were evaluated. A possible solution to the problem posed by this type of screens was also studied, as it is necessary to look away from the road in order to see the screen. For this reason, it was decided to incorporate a HUD (Head-Up Display) device that contains a transparent screen and can be located in the visual field of driving in order to be able to view information about the context in which the vehicle is moving. The results obtained are encouraging and verify the great acceptance and usability that this sort of systems of information visualization has among users.
In the line of environmental sustainability, it was proposed by the research group in which this thesis is developed that the networks of mobile vehicles could be a possible solution for the measurement of environmental pollution. Accordingly, an environmental monitoring service was installed in public transport (buses, waste collection vehicles, etc.), capable of measuring environmental pollution in the city. The main problem that we faced was how to represent this kind of information to make it understandable for the general public. For this reason, it was decided to carry out a subjective test on methods to represent information of this type. The results revealed the most appropriate representations of pollution, as well as the devices on which to visualize them and the types of data of most interest to the different groups of users.
As we can see, this PhD Thesis proposes an extensive study on vehicle network environments and their inclusion in a Smart City environment, emphasizing the theme of smart mobility and environmental sustainability, without forgetting the technology necessary for the real implementation of new solutions, with the focus firmly on both improving transport in the city and the quality of life of citizens.
Keywords: Vehicular Networks, Smart Mobility, Environmental Sustainability, Smart City.
5 citations
Cites background from "4G: LTE/LTE-Advanced for Mobile Bro..."
...11, podemos atender al uso de tecnologías establecidas por el 3GPP (The 3rd Generation Partnership Project), como por ejemplo, GPRS [45], 3G [46], 4G [47] e incluso tecnologías de reciente aparición y todavía no implantadas de forma amplia, como 5G, para la comunicación de dispositivos [48] que están siendo utilizadas en estudios recientes dentro de entornos de comunicaciones vehiculares [49]....
[...]
01 Aug 2020
TL;DR: In this paper, the outage probability and per-block average pairwise error probability (PEP) were derived for the selective decode and forward cooperative communication system and investigated its performance over time-selective fading in the presence of nodes mobility and channel estimation errors.
Abstract: In this paper, we consider the selective decode and forward cooperative communication system and investigate its performance over time-selective fading in the presence of nodes’ mobility and channel estimation errors. Closed-form expressions for the outage probability (OP) and per-block average pairwise error probability (PEP) are derived, considering constraints at the relay, source, and destination nodes. We assume that both dual and multiple hops are subject to independent but non-identically distributed time-selective Nakagami-m fading channel. It has been observed that with an increase in the value of shape parameter and link strength of the relay-to-destination (RD) fading link gain, the per-block average PEP performance improves. Also increasing RD link gain is more significant than increasing the shape parameter of the RD link. The OP performance for optimal power allocation factors is better than its performance for equal power allocation factors. It is demonstrated that the OP decreases with increasing the value of distance-dependent power transfer factors (PTFs). Further, it has been observed that due to the mobility of nodes and imperfect channel state information, the PEP performance of the system experiences degradation, especially for high values of signal-to-noise ratio. Furthermore, when all the nodes are static and the estimation processes are perfect, the asymptotic error floors vanish, i.e., the nodes' mobility impact is removed. Monte Carlo simulation results confirm the accuracy of the analytical results.
5 citations
19 Dec 2013
TL;DR: In this paper, the authors proposed a new approach of relay placement to enhance the capacity of cell edge user in inter-band carrier aggregation scenario with asymmetrical coverage, where relay can be used to solve the problem of capacity fairness for non-overlapped region produced by the lower frequency component carrier in interband aggregation.
Abstract: Relaying and carrier aggregation are two main features of Long Term Evolution Advanced (LTE-A) that improve the transmission and increase the capacity of the network. Besides, enhance the overall capacity inside the coverage area of a relay. A relay can be used to solve the problem of capacity fairness for non-overlapped region produced by the lower frequency component carrier in inter-band carrier aggregation. This paper proposes a new approach of relay placement to enhance the capacity of cell edge user in inter-band carrier aggregation scenario with asymmetrical coverage. A simulation model for LTE-A in the downlink has been developed to investigate the impact of relay placement. The simulation result shows that a relay can be placed inside the overlapped coverage region to enhance the capacity of the cell edge user. The study suggests that for average cases a relay should be placed closer to the middle of the cell produced by lower frequency component carrier. For extreme cases with higher path-loss exponent and for larger interband gaps, the relay should be placed closer to the cell edge. Furthermore, the optimal position of the relay is closer to the cell edge when the link budget of relay is much smaller than the eNodeB (eNB).
5 citations
TL;DR: Three schemes to enable overhead-efficient massive MIMO in noncontiguous bands with frequency-selective channels are presented and novel resource adaptation mechanisms between uplink and downlink are proposed and analyzed.
Abstract: Massive MIMO systems offer large spectrum efficiency improvements but when applied to systems with noncontiguous bands as commonly encountered in practice, their performance gains are largely offset by the overhead in acquiring channel state information (CSI). This paper presents three schemes to enable overhead-efficient massive MIMO in noncontiguous bands with frequency-selective channels. By incorporating CSI errors, CSI overhead, pilot contamination, and guard interval cost, achievable rate or throughput expressions of uplink and downlink of the proposed schemes are derived. Novel resource adaptation mechanisms between uplink and downlink are proposed and analyzed. Compared with the conventional frequency division duplexing scheme, analytical/numerical studies elaborate substantial spectrum efficiency enhancement, and flexible resource adaptation capability of the proposed schemes.
5 citations
Cites background from "4G: LTE/LTE-Advanced for Mobile Bro..."
..., see LTE frequency channels [5], due to preexisting spectrum allocations and non-availability of a sufficient single contiguous band....
[...]
..., with different UL and DL frame durations or with different numbers of UL and DL sub-frames of the same duration [5]....
[...]
TL;DR: This paper presents a long-term evolution (LTE) receiver (RX) front end with a digital filtering analog to digital converter (ADC) in the baseband to perform multi-band blocker cancellation.
Abstract: This paper presents a long-term evolution (LTE) receiver (RX) front end with a digital filtering analog to digital converter (ADC) in the baseband to perform multi-band blocker cancellation. The digital filtering ADC has a digitally defined transfer function that is highly reconfigurable and insensitive to PVT variations. The dynamic range requirement of the blocker cancellation feedback digital to analog converter (DAC) is relaxed with a trivial uncalibrated first-order passive high-pass filter. The programmable digital filter provides 34.9-dB attenuation of transmitter leakage and variable attenuation of an additional blocker anywhere in the frequency range 17.5–107.5 MHz. A blocker detection algorithm for this RX is presented and takes approximately 26 $\mu \text{s}$ to converge. The RX front end operates at 1.8 GHz with a noise figure of 3.9 dB and IIP3 of −5 dBm, and consumes only 20.4–37.5 mW, the lowest among the state-of-the-art designs.
5 citations
Cites background from "4G: LTE/LTE-Advanced for Mobile Bro..."
...To compensate the rapid and significant variations in the channel conditions, the LTE standard provides an automatic repeat request (ARQ) [11]....
[...]
...In an ARQ scheme, for every block of data 1 ms in length, the RX relies on error detection to detect uncorrectable errors....
[...]