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
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Patent•
17 Dec 2014TL;DR: In this article, the authors describe a hierarchical wireless communications system with a first layer with first layer transmissions having a first subframe type and a second layer with second layer transmissions with second subframe types, where the first layer has a first round trip time (RTT) between transmission and acknowledgment of receipt of the transmission, and the second layer may have a second RTT that is less than the first RTT.
Abstract: Methods, systems, and devices are described for hierarchical communications within a wireless communications system. An eNB and/or a UE may be configured to operate within the wireless communications system which is at least partially defined through a first layer with first layer transmissions having a first subframe type and a second layer with second layer transmissions having a second subframe type. The first subframe type may have a first round trip time (RTT) between transmission and acknowledgment of receipt of the transmission, and the second layer may have a second RTT that is less than the first RTT. Subframes of the first subframe type may be multiplexed with subframes of the second subframe type, such as through time division multiplexing.
7 citations
11 Dec 2013
TL;DR: The downlink worst case Signal to Interference Ratio for FFR schemes is analyzed and a closed form expression is derived analytically for the worst SIR, outage probability, and Spectral efficiency.
Abstract: Fractional Frequency Reuse (FFR) is an efficient method to mitigate Inter Cell Interference in multicellular Orthogonal Frequency Division Multiple Access (OFDMA) systems. In this paper, we analyze the downlink worst case Signal to Interference Ratio for FFR schemes. A closed form expression is derived analytically for the worst SIR, outage probability, and Spectral Efficiency (SE). The proposed analytical technique is used to configure a FFR solution for the downlink of OFDMA cellular system. The analysis is performed using two-tiers cellular network with uniform user density and for three different cases of FFR, namely, Frequency Reuse Factor (FRF) = 3, FRF=4 and sectored FFR. The inner radius configuration depends on equalizing the worst SIR for both inner and outer edges of the cell. Numerical results show that sectored FFR yields the highest SE and low outage probability. Sectored FFR highly balances the needs of interference reduction and resource efficiency.
7 citations
TL;DR: It is concluded that RAP 1 and RAP 2 is more suitable for underwater acoustic cellular systems.
Abstract: In this paper, a random access preamble (RAP) design technique for underwater acoustic cellular systems is proposed. After showing that the conventional RAP used in long term evolution (LTE) systems is not appropriate for underwater acoustic cellular systems, two different types of RAPs (RAP 1 and RAP 2) are proposed to detect the identity of underwater equipment/nodes (UEs) and estimate the time delay between a UE and an underwater base station (UBS) at the physical layer. RAP 1 is generated using a Zadoff-Chu (ZC) sequence where the identity of the UE is mapped to its root index, whereas RAP 2 is generated using a linear frequency modulation (LFM) waveform where the identity of the UE is mapped to its frequency sweeping parameter and frequency shifting parameter. Ambiguity functions (AFs) and cross-ambiguity functions (CAFs) of RAP 1 and RAP 2 are derived to investigate their correlation properties under the effect of time delay and Doppler shift. The performance of RAP detection is investigated by analyzing the detection probabilities and false alarm probabilities of RAP 1 and RAP 2 in a Doppler environment. By evaluating the performances of RAP 1 and RAP 2 in various situations, it is concluded that RAP 2 is more suitable for underwater acoustic cellular systems. The AF and CAF analytically obtained in this paper are shown to be similar to those obtained using experimental data.
7 citations
Cites background from "4G: LTE/LTE-Advanced for Mobile Bro..."
...In order to establish a communication link, the UE should perform downlink synchronization and cell searching by receiving synchronization and broadcasting signals [10]....
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TL;DR: It is shown that, under power ramping and default PDCCH capacity, increasing the number of retransmissions beyond 1 or at most 2 does not bring any benefits and, in fact, is detrimental to system capacity.
Abstract: In this paper, we examine the impact of power ramping, number of retransmission attempts, and limitations of the physical downlink control channel (PDCCH) on the performance of random access in Long Term Evolution/Long Term Evolution-Advanced networks. We demonstrate that positive feedback exists between the maximum number of retransmissions, age-based power ramping, and PDCCH deficiency. As the result, system capacity is decreased and performance deteriorates abruptly under moderate to high traffic intensity. We show that, under power ramping and default PDCCH capacity, increasing the number of retransmissions beyond 1 or at most 2 does not bring any benefits and, in fact, is detrimental to system capacity. Increasing PDCCH capacity would enable the benefits of power ramping and allow more retransmission attempts. However, increasing the number of retransmissions combined with power ramping, while helpful under moderate to high load, will decrease system capacity.
7 citations
Cites background or methods from "4G: LTE/LTE-Advanced for Mobile Bro..."
...Handoff calls should be collision-free as they use a separate subset of preambles and a different contention-free handshake [1], [2]....
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...In case of preamble detection, SINR is expressed as Ep N0 , the ratio of the energy of the entire preamble sequence and spectral density of noise power [1], [2]....
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...Signal attenuation can be countered by longer preamble time of 1600 μs, as opposed to the default value of 800 μs, while longer propagation delays can be countered by extending the CP and GT sub-intervals [1]....
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...RANDOM access in Long Term Evolution/Long Term Evolution-Advanced (LTE/LTE-A) cells is necessary for initial access or area tracking by a terminal (User Equipment, UE) that is not connected, or for uplink synchronization with the scheduler of the Evolved Node B (eNodeB) when a connected UE needs to transmit uplink data or perform a handoff to the target cell [1], [2]....
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...As noted above, handoff calls use an exclusive set of Nh preambles and deploy a contention-free random access procedure [1], [2]....
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01 Jan 2013
TL;DR: This study study and analyze the Quality of Experience (QoE) at the end user for Video on Demand (VoD) over the LTE network, and provides performance evaluation to characterize the impact of transport layer protocol in video streaming over radio networks like LTE.
Abstract: In recent years, the mobile Internet has increased dramatically with the development of 3G and 4G technologies. Especially the usage of mobile broadband internet on the devices like cellular mobiles, Tablets and Laptops has skyrocketed. Among the multimedia applications video streaming is the most popular mobile application. But, making these services available to users in a cost effective way without compromising quality is a big challenge. The development of Long Term Evolution (LTE) technology in the mobile world made this task achievable. The features of LTE technology provide effective services in multimedia applications with high data rates and low latency. In this paper, we study and analyze the Quality of Experience (QoE) at the end user for Video on Demand (VoD) over the LTE network. To achieve this, we streamed High Definition (HD) videos based on H.264/AVC and these videos are delivered from source to destination using Transport Control Protocol (TCP) and User Datagram Protocol (UDP). Specifically, our study is about QoE evaluation in terms of delay variation, packet loss metrics and provides performance evaluation to characterize the impact of transport layer protocol in video streaming over radio networks like LTE. In order to know the performance of video streaming over LTE network, we also evaluate the LTE performance in terms of one-way delay, packet loss and inter packet delay for the generated UDP and TCP packets.
7 citations