LTE-advanced: next-generation wireless broadband technology [Invited Paper]
TL;DR: An overview of the techniques being considered for LTE Release 10 (aka LTEAdvanced) is discussed, which includes bandwidth extension via carrier aggregation to support deployment bandwidths up to 100 MHz, downlink spatial multiplexing including single-cell multi-user multiple-input multiple-output transmission and coordinated multi point transmission, and heterogeneous networks with emphasis on Type 1 and Type 2 relays.
Abstract: LTE Release 8 is one of the primary broadband technologies based on OFDM, which is currently being commercialized. LTE Release 8, which is mainly deployed in a macro/microcell layout, provides improved system capacity and coverage, high peak data rates, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operation and seamless integration with existing systems. LTE-Advanced (also known as LTE Release 10) significantly enhances the existing LTE Release 8 and supports much higher peak rates, higher throughput and coverage, and lower latencies, resulting in a better user experience. Additionally, LTE Release 10 will support heterogeneous deployments where low-power nodes comprising picocells, femtocells, relays, remote radio heads, and so on are placed in a macrocell layout. The LTE-Advanced features enable one to meet or exceed IMT-Advanced requirements. It may also be noted that LTE Release 9 provides some minor enhancement to LTE Release 8 with respect to the air interface, and includes features like dual-layer beamforming and time-difference- of-arrival-based location techniques. In this article an overview of the techniques being considered for LTE Release 10 (aka LTEAdvanced) is discussed. This includes bandwidth extension via carrier aggregation to support deployment bandwidths up to 100 MHz, downlink spatial multiplexing including single-cell multi-user multiple-input multiple-output transmission and coordinated multi point transmission, uplink spatial multiplexing including extension to four-layer MIMO, and heterogeneous networks with emphasis on Type 1 and Type 2 relays. Finally, the performance of LTEAdvanced using IMT-A scenarios is presented and compared against IMT-A targets for full buffer and bursty traffic model.
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05 Apr 2011
TL;DR: Measurement results for coordinated multi-point downlink transmissions as Long Term Evolution - Advanced concept from a cellular test bed in Dresden, Germany are presented.
Abstract: This paper presents measurement results for coordinated multi-point downlink transmissions as Long Term Evolution - Advanced concept from a cellular test bed in Dresden, Germany. At first, a description of the real-time prototyping system and its signal processing introduces the major modifications from the existing 3GPP-LTE standard. Then, the cellular propagation and measurement environment of the test bed is characterized. Various spatial setups are compared in conjunction with cooperative and non-cooperative base stations as well as cell-center and cell-edge scenarios. Finally, results concerning the geometry factor, time difference of arrivals and spectral efficiencies complete this field trial.
7 citations
Cites background from "LTE-advanced: next-generation wirel..."
...Furthermore, interference mitiga tion is impossible for cell-edge users with almost symmetric DL power levels between two BSs and without BS coop eration [11]....
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01 Oct 2012
TL;DR: The downlink resource allocation problem joining both carrier component (CC) allocation and resource block (RB) allocation is formulated to achieve proportional fairness in the long term and a maximum system utility (MSU) algorithm is developed.
Abstract: To achieve a higher data transmission rate, carrier aggregation (CA) technology has been included in the LTE Advanced standard. Allocating resources with CA is a crucial and challenging task due to the different types of user equipment (UE) that have different bandwidth capacities and operate under the same base station (BS). We have formulated the downlink resource allocation problem joining both carrier component (CC) allocation and resource block (RB) allocation to achieve proportional fairness in the long term. We also develop a maximum system utility (MSU) algorithm. Each time this algorithm tries to allocate the best CC to an narrow-band UE in which the number of CCs it is assigned does not exceed the number of CCs supported, maximizing the total utility until it can no longer grow. Importantly, NB UEs which can support more than one CCs are considered in this paper. Simulation results show that the proposed algorithm can significantly improve total throughput compared with the existing algorithm both with and without fairness consideration.
7 citations
Cites background from "LTE-advanced: next-generation wirel..."
...To meet these requirements, carrier aggregation (CA) [4] has been included as a feature in the LTE Advanced standard....
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...Consider a downlink LTE Advanced system with |K| UEs that include |K1| narrow-band (NB) UEs and |K2| broadband (BB) UEs (|K|=|K1|+|K2|)....
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...[10] have provided a mathematical model of the log-measure utility in an LTE Advanced system and have shown that cross-CC-PF can achieve optimal network utility as defined by the sum of the logarithmic user throughput....
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...In this paper, we formulate the optimal resource allocation problem with carrier aggregation in an LTE Advanced system with the aim of achieving proportional fairness in the long term....
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...Research on resource allocationbased CA in LTE Advanced systems is therefore crucial....
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01 Jul 2013
TL;DR: A theoretical closed form solution is provided for the utility based resource allocation algorithm as well as a heuristic solution that is shown to yield significant gains of up to 36% compared to the baseline approach.
Abstract: In this paper, we study the strategic coexistence of macro and pico cells and investigate a utility based resource allocation technique for heterogeneous networks. Aiming at finding an objective driven allocation of resources, we focus on time domain inter-cell interference coordination (ICIC) techniques. Macro and pico cells optimally select their almost blank subframe (ABS) muting rate and cell range bias values, so that inter-cell offloading and enhanced ICIC (e-ICIC) are jointly performed. A theoretical closed form solution is provided for our utility based resource allocation algorithm as well as a heuristic solution. To substantiate our theoretical findings, system level simulations are carried out in which the proposed heuristic solution is compared to a baseline ICIC technique. Interestingly, our proposed solution is shown to yield significant gains of up to 36% compared to the baseline approach.
7 citations
Cites background from "LTE-advanced: next-generation wirel..."
...…LTE; RRM; ICIC; ABS; CRE I. INTRODUCTION The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE)-Advanced has investigated the heterogeneous network deployments as a cost effective way to improve performance especially for unequal user equipment (UE) or traffic distribution [1]....
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01 Dec 2012
TL;DR: The effect of the separation of uplink and downlink from an energy efficient point of view is studied under the evaluation of the LTE-Advanced system level simulation.
Abstract: With the rapid development of wireless personal communications, demand for higher rates and bandwidth becomes more and more significant In order to satisfy the need, network providers tried to deploy more and more access points such as the RRHs, which can effectively increase spectrum efficiency and ensure reliable QoS to users In fact, demand for resources in uplink and downlink is not equal in many of the services, such as online movie, downloading, etc So the separation of uplink and downlink is developed, which allows the heavy traffic for downlink can be served by RRHs and the light one for uplink can be directly served by traditional micro/macro cell Traditional research of the heterogeneous networks of LTE-Advanced mainly focus on system performance But in this paper, we studied the effect of the separation from an energy efficient point of view under the evaluation of the LTE-Advanced system level simulation The design of signaling to implement the separation is firstly raised The cost and performance of the separation are also evaluated and fully analyzed
7 citations
TL;DR: All relevant schemes appearing on the road-map in the unified frame-work of forward error correction in the NLMC system are summarized.
Abstract: In the paper, we present a road-map towards a near-capacity large-scale multi-user cooperative-communications (NLMC) system, where all the evolution paths converge to the construction of the NLMC system. More specifically, we will summarize all relevant schemes appearing on the road-map in the unified frame-work of forward error correction. various network coding design paradigms are highlighted for illustrating how the NLMC systems might be designed for meeting diverse design criteria in the context of cooperative and cognitive communications, where the channel capacity of the NLMC systems is used for comparing the different design paradigms.
7 citations
References
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01 Sep 2006
TL;DR: A preliminary look at the air interface for Evolved UTRA (E-UTRA) and associated key technologies required to reach its design objectives are provided.
Abstract: With the emergence of packet-based wireless broadband systems such as 802.16e, it is evident that a comprehensive evolution of the universal mobile telecommunications system specifications is required to remain competitive. As a result, work has begun on long term evolution (LTE) of the UMTS terrestrial radio access and radio access network aimed for commercial deployment in 2010. Goals for the evolved system include support for improved system capacity and coverage, high peak data rates, low latency, reduced operating costs, multi-antenna support, flexible bandwidth operations and seamless integration with existing systems. To reach these goals, a new design for the air interface is envisioned. This paper provides a preliminary look at the air interface for Evolved UTRA (E-UTRA) and associated key technologies required to reach its design objectives. Initial E-UTRA system performance results show a 2 to 3x improvement over a reference Rel-6 UMTS system configuration [1, 2] for both uplink and downlink.
30 citations
24 Oct 2008
TL;DR: The proposed channel estimation technique is shown to have significant gains in performance compared to other well known channel estimation techniques such as the maximum-likelihood (ML) and the inverse fast Fourier transform (IFFT) channel estimation methods.
Abstract: The performance of the uplink physical channel of the 3GPP LTE system is considered in this paper. Assuming a single user spatial division multiple access transmission scheme, where users' signals are transmitted over different subcarriers, a low complexity channel estimation technique is proposed for the physical uplink shared channel (PUSCH). The proposed channel estimation technique is shown to have significant gains in performance compared to other well known channel estimation techniques such as the maximum-likelihood (ML) and the inverse fast Fourier transform (IFFT) channel estimation methods [5]. Simulation results for different channel models and modulation and coding schemes (MCS) using incremental redundancy (IR) based hybrid automatic repeat request (HARQ) operation are also shown. Finally, a robust detection scheme is proposed for the physical uplink control channel (PUCCH) and simulation results are summarized.
10 citations
"LTE-advanced: next-generation wirel..." refers methods in this paper
...The DFT precoding operation is performed to reduce the cubic metric (CM) of the signal, leading to higher maximum transmit power [2]....
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