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.

LTE-Advanced Air Interface Technology

Abstract: Opportunities are at hand for professionals eager to learn and apply the latest theories and practices in air interface technologies. Written by experienced researchers and professionals, LTE-Advanced Air Interface Technology thoroughly covers the performance targets and technology components studied by 3GPP for LTE-Advanced. Besides being an expla

An architecture for mobile computation offloading on cloud-enabled LTE small cells

Abstract: Small cell networks are currently seen as a new way to satisfy the increasing wireless traffic demand. The proximity of base stations to subscribers brings many possibilities for the development of new applications, including new offerings based on cloud computing. Smartphones can directly offload applications to close base stations, provided that these are equipped with additional computational and storage resources. The cloud concept applied in the framework of small cells can also combine radio and computation aspects in order to optimise the service delivery. This paper introduces a new element called the Small Cell Manager (SCM), which optimises the overall operation of a cluster of cloud-enabled small cells. The SCM, aware of the cluster situation in terms of both radio and cloud aspects, interacts not only with the cloud-enabled base stations, but also with LTE core network components. To that end, different possibilities for the general architecture of a small-cell-cloud are analysed. Furthermore, the paper describes different evaluation criteria an LTE operator has to consider before adopting this approach in order to optimise the required investment and maximise benefits.

Trellis-Extended Codebooks and Successive Phase Adjustment: A Path from LTE-Advanced to FDD Massive MIMO Systems

Abstract: It is of great interest to develop efficient ways to acquire accurate channel state information (CSI) for frequency division duplexing (FDD) massive multiple-input multiple-output (MIMO) systems for backward compatibility. It is theoretically well known that the codebook size for CSI quantization should be increased as the number of transmit antennas becomes larger, and 3GPP long term evolution (LTE) and LTE-Advanced codebooks also follow this trend. Thus, in massive MIMO, it is hard to apply the conventional approach of using pre-defined vector-quantized codebooks for CSI quantization mainly because of codeword search complexity. In this paper, we propose a trellis-extended codebook (TEC) that can be easily harmonized with current wireless standards such as LTE or LTE-Advanced by extending standardized codebooks designed for 2, 4, or 8 antennas with trellis structures. TEC exploits a Viterbi decoder and convolutional encoder in channel coding as the CSI quantizer and the CSI reconstructer, respectively. By quantizing multiple channel entries simultaneously using standardized codebooks in a state transition of trellis search, TEC can achieve fractional bits per channel entry quantization to have a practical feedback overhead. Thus, TEC can solve both the complexity and the feedback overhead issues of CSI quantization in massive MIMO systems. We also develop trellis-extended successive phase adjustment (TE-SPA) which works as a differential codebook of TEC. This is similar to the dual codebook concept of LTE-Advanced. TE-SPA can reduce CSI quantization error even with lower feedback overhead in temporally correlated channels. Numerical results verify the effectiveness of the proposed schemes in FDD massive MIMO systems.

Security Issues in Next Generation Mobile Networks: LTE and Femtocells

Abstract: Cellular mobile networks are used by more than 4 billion users worldwide. One effective way to meet the increasing demand for data rates is to deploy femtocells, which are low-power base stations that connect to the mobile operator through the subscriber's residential Internet access. Yet, security and privacy issues in femtocell-enabled cellular networks, such as UMTS and LTE, still need to be fully addressed by the standardization bodies. In this paper, we review significant threats to the security and privacy of femtocell-enabled cellular networks. We also propose novel solution directions in order to tackle some of these threats by drawing inspiration from solutions to similar challenges in wireless data networks such as WLANs and mobile ad hoc networks (MANETs).

Comparison of Relay and Pico eNB Deployments in LTE-Advanced

Abstract: Relaying is one of the most important novel elements in 3GPP LTE-Advanced study item. It promises to offer significant gain for system capacity or coverage depending on the deployment prioritization. In this paper, we investigate the feasibility of relay node deployments in terms of system throughput and cell coverage area extension as compared to pico node deployments and traditional homogeneous single-hop macro cells. Relay backhaul link overhead is taken into consideration as a limiting factor in a relay deployment; nevertheless, results show that its effect on coverage extension is in most cases negligible. While the effect of relay backhaul overhead is small in coverage limited scenarios, the limitations on throughput due to relaying are evident, in particular, for 500m ISD scenarios. This study also demonstrates that both relay and pico node deployments outperform clearly traditional macro cell deployment in terms of coverage and network capacity.