LTE Advanced

About: LTE Advanced is a research topic. Over the lifetime, 4055 publications have been published within this topic receiving 74262 citations. The topic is also known as: Long-Term Evolution Advanced & LTE-A.

A dynamic approach for cell range expansion in interference coordinated LTE-advanced heterogeneous networks

Abstract: Cell range expansion is one of the features of LTE-advanced where low power nodes in a heterogonous network can increase their coverage area and neighboring cells can offload particular users accordingly The amount of expansion however can differ from one cell to another depending on the location of the low power node with respect to the neighboring cells, the cell load and the method of interference coordination utilized A study is made in this paper to examine the impact of dynamically changing the range of low power nodes in the presence of a time based ICIC method A simple heuristic method is proposed which adapts the size of the low power nodes to the load and interference situation Results show that dynamic range expansion provides better performance for the 5th and 50th percentile users but causes loss to the 95th percentile users of a system

Efficient and practical resource block allocation for LTE-based D2D network via graph coloring

Abstract: In this paper, we construct a practical framework for efficiently allocating long term evolution (LTE) resource blocks (RB) among the users in a device-to-device (D2D) network. For such network that presumably operates under the LTE cellular network, our aim is to improve the overall throughput of D2D connections using opportunistic or fairness-based approach. Taking the practical considerations into account, our proposed framework allows a number of connections to share a single RB whenever possible, thus utilizing the radio resources. To do so, our solution first identifies a superior set of the interference-free D2D reuse groups via graph modeling and graph coloring approach. In particular, we model a D2D network with a two-overlapping disk graph for which a suitable coloring algorithm is proposed and its performance bound is calculated. Once the reuse groups are known, our solution optimizes the RB allocation among these groups based on their reported channel condition as well as the scheduling criterion, whether it is fairness-based or opportunistic. Through numerical experiments, we show that our solution can significantly improve the throughput performance of a D2D network.

The development of TD-SCDMA 3G to TD-LTE-advanced 4G from 1998 to 2013

Abstract: TD-SCDMA and TD-LTE-Advanced are two global TDD standards adopted by ITU for the Third Generation and the Fourth Generation of mobile communication. TD-LTE, the evolution of TD-SCDMA, is accepted by more and more operators and manufactures leading to global deployment in the world. As the global mobile communication standards initially promoted by China, a developing country, TD-SCDMA and TD-LTE always attract much curiosity and interest. This article reviews the standardization and development history from TD-SCDMA 3G to TD-LTE-Advanced 4G in the period 1998 to 2013. It is indicated that TD-SCDMA opened a sustainable utilization era of TDD technology in 3G and 4G. It is believed that TDD will play a more important role in 5G. Key factors promoting the successful progress of standardization and commercialization are analyzed.

Long-Term Channel Information-Based CoMP Beamforming in LTE-Advanced Systems

Abstract: Coordinated multi-point (CoMP) transmission and reception is a network multiple-input multiple- output (MIMO) technology considered in 3GPP LTE- Advanced systems. In order to improve reliability and capacity of the services for the user equipments (UEs) at the cell edges, CoMP utilizes cooperation among neighboring enhanced node Bs (eNBs). Accordingly, backhaul delay for sharing control signals among eNBs should be carefully handled as UE mobility increases in a fading channel environment; otherwise, CoMP operations derived from inaccurate channel state information (CSI) of neighboring eNBs can severely degrade the system performance. We propose CoMP beamforming schemes using long-term CSI such as spatial correlation matrices instead of instantaneous CSI of neighboring cells. Since long- term CSI varies relatively slowly, the proposed scheme is inherently robust even when a UE moves at a high speed and/or the backhaul delay is large. Using a multi-cell simulator which reflects realistic CoMP system environments, the performance gain of the proposed schemes is evaluated and discussed.

Flexible Backhaul Resource Sharing and Uplink Power Control Optimization in LTE-Advanced Relay Networks

Abstract: Type 1 inband relaying, as being standardized in 3GPP LTE-Advanced, supports a relaying mode where the backhaul link transmission is time-division multiplexed with the access link transmission, whereas macro users share the same resources with the relays. Hence, system performance depends strongly on the resource sharing and allocation strategy among and within the different links. Moreover, the set of subframes assigned for the backhaul transmission is semi-statically configured and thus a dynamic reconfiguration to adapt to fast-changing system conditions, e.g. relay cell load, is not viable. In order to tackle the above issues, we propose a statistic-based over-provisioned backhaul subframe allocation to be utilized for flexible co scheduling of relays and macro users at the donor eNB. In addition, a power control optimization is investigated to enhance overall system performance and to reduce the donor eNB receiver dynamic range. Performance evaluation is carried out within the LTE Advanced uplink context in urban and suburban scenarios. Results as well show that the proposed scheme achieves significant throughput gains.