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.

Top challenges of LTE to become the next generation railway communication system

Abstract: Railway environments cannot be away from the current evolution of public communication systems. The Long Term Evolution (LTE) mobile communication system is considered to be the natural evolution for current Global System for Mobile Communications Railways (GSM-R). LTE all IP networking technology plays a key role for the integration and convergence of heterogeneous networks and services, both the specific for the railway operative and the commercial broadband ones for passengers. The adoption of a new generation standard for railway communication must be based on an exhaustive feasibility study of the new system to become the railway mobile communication system. In this paper, LTE’s top challenges to address the specific requirements and features of railway communication services are evaluated. Under this scope, LTE features to implement the required railway functionalities, LTE technical challenges, spectrum harmonization, network deployment considerations and LTE capabilities to meet the railway service Reliability, Availability, Maintainability and Safety (RAMS) requirements, are assessed.

A Broadband High-Efficiency SOI-CMOS PA Module for LTE/LTE-A Handset Applications

Abstract: This paper presents a broadband high-efficiency linear Doherty power amplifier (DPA) for LTE/LTE-A handset applications. The proposed PA is implemented in a 130nm SOI technology and packaged using flip-chip on a laminate substrate. At 2.5GHz, the PA shows a PAE of 44%, a power gain of 27dB, and an E-UTRA ACLR of −35dBc at 28dBm output power using a 10MHz LTE uplink signal without DPD. Moreover, the PA reaches a maximum FOM (PAE+|ACLR|) of 80 and maintains a FOM greater than 70 over 31% of fractional bandwidth around 2.3GHz without using DPD. When using DPD, the ACLR is improved by 10dB leading to a maximum FOM of 90. To the best of our knowledge, these performances represent the best linearity-efficiency performances compared to recently published LTE PAs for handset applications.

Prediction-based handover schemes for relay-enhanced LTE-A systems

Abstract: Relay nodes (RN) have been suggested to be placed near the edge of a cellular network in order to improve link qualities of cell edge user equipments (UEs). Compared to conventional homogeneous networks, system performance for the relay-enhanced network can be significantly degraded if handovers between the RNs and evolved node base-station (eNB) are not correctly and immediately determined by the eNB. Therefore, the UEs may suffer from worse channel conditions which can result in increased energy consumption of entire network. In existing long term evolution advanced (LTE-A) standard, fixed reporting time period from the UEs to eNB is considered inflexible which can be too long to provide immediate handover decisions. Hence, prediction-based handover (PH) scheme is proposed to allow eNBs to make potential handover decisions within the UE's reporting period. The channel qualities for both the direct and relay-enhanced links during this period are predicted based on the partially observable Markov decision process. Moreover, three objectives are designed for the proposed PH scheme including maximizing received signal to interference plus noise ratios of UEs, and minimizing system energy consumption without and with considerations of energy outage of relay nodes. Numerical results show that the proposed PH schemes outperform conventional handover scheme from the perspectives of both system energy consumption and outage probability.

Sequence mapping for LTE/LTE-A with unlicensed spectrum

Abstract: Sequence mapping for reference signal is disclosed in which the reference signal sequence at the fixed set of resource blocks around a predetermined common frequency is generated to be independent from the system bandwidth. The reference signal sequence may be generated around the predetermined common frequency or may be configured based on a cell identifier. Either such solution provides a system bandwidth independent means for a user equipment (UE) to detect the reference signal sequence for decoding a bandwidth information bearing signal received from the communicating base station.