Evolution of reference signals for LTE-advanced systems

Nam, Young‐Han; Akimoto, Yusuke; Kim, Younsun; Lee, Moon-il; Bhattad, Kapil; Ekpenyong, A.

doi:10.1109/mcom.2012.6146492

Cited by 52 publications

(38 citation statements)

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“…Therefore, before the BS transmits data symbols, it sends K distinct 1 × τ dn orthogonal pilot sequences. For example, in the LTE-Advanced system, precoded downlink pilot signal called user equipment specific reference signal (UE-RS) is employed to enable each user to estimate its effective downlink channel [24]. The accuracy of the estimated effective downlink channel depends on the downlink pilot power of the BS.…”

Section: ) Downlink Effective Channel Estimationmentioning

confidence: 99%

Energy Efficient Pilot and Link Adaptation for Mobile Users in TDD Multi-User MIMO Systems

Kim

Miao

Hwang

2014

IEEE Trans. Wireless Commun.

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Abstract-In this paper, we develop an uplink pilot and downlink link adaptation approach to improve the energy efficiency (EE) of mobile users in time division duplexing (TDD) multiuser multiple input and multiple output (MU-MIMO) systems. Assuming reciprocity between uplink and downlink channels, the downlink transmission is based on uplink channel estimation. While more uplink pilot power ensures more accurate channel estimation and better downlink performance, it incurs higher energy consumption of mobile users. This paper reveals the relationship and tradeoff among pilot power, channel estimation, and downlink link adaptation that achieves the highest energy efficiency for mobile users. We show that the energy efficiency of different users can be decoupled because the downlink average throughput of each user is independent of the pilot powers of other users and energy-efficient design can be done on a peruser basis. Based on the analysis, we propose an uplink pilot and downlink link adaptation algorithm to improve the EE of mobile users. Simulation results are finally provided to demonstrate the significant gain in energy efficiency for mobile users.

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Section: ) Downlink Effective Channel Estimationmentioning

confidence: 99%

Energy Efficient Pilot and Link Adaptation for Mobile Users in TDD Multi-User MIMO Systems

Kim

Miao

Hwang

2014

IEEE Trans. Wireless Commun.

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“…In addition, new techniques in reference signals were also introduced in release 10 [76,77]. An adaptive design method for the reference signals in LTE-Advanced was also proposed in [78].…”

Section: Technical Aspectsmentioning

confidence: 99%

LTE-Advanced Radio Access Enhancements: A Survey

Dehghani

Arshad

MacKenzie

2014

Wireless Pers Commun

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Long Term Evolution Advanced (LTE-Advanced) is the next step in LTE evolution and allows operators to improve network performance and service capabilities through smooth deployment of new techniques and technologies. LTE-Advanced uses some new features on top of the existing LTE standards to provide better user experience and higher throughputs. Some of the most significant features introduced in LTE-Advanced are carrier aggregation, enhancements in heterogeneous networks, coordinated multipoint transmission and reception, enhanced Multiple Input Multiple Output (MIMO) usage and deployment of relay nodes in the radio network. Mentioned features are mainly aimed to enhance the radio access part of the cellular networks. This survey article presents an overview of the key radio access features and functionalities of the LTE-Advanced radio access network, supported by the simulation results. We also provide a detailed review of the literature together with a very rich list of the references for each of the features. An LTE-Advanced roadmap and the latest updates and trends in LTE markets are also presented.

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“…To facilitate such channel estimation, the LTE-Advanced standard has defined several different kinds of reference signals (RS) to deal with different system setups. In particular, it specifies the so-called user equipment (UE)-specific reference signals (short-named DM-RS) to support noncodebook-precoding in multi-input multi-output (MIMO) downlink signal transmission [1], [2]. As illustrated in Fig.…”

Section: Introductionmentioning

confidence: 99%

LMMSE-Based Channel Estimation for LTE-Advanced MIMO Downlink Employing UE-Specific Reference Signals

Hsieh

Lin²,

2015

2015 IEEE 81st Vehicular Technology Conference (VTC Spring)

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The LTE-Advanced wireless communication standard specifies UE-specific reference signals (short-named DM-RS) to facilitate multi-input multi-output (MIMO) downlink channel estimation. This paper presents a linear minimum meansquare error (LMMSE)-based channel estimation technique in this context. Key to LMMSE channel estimation is the acquisition of some second-order channel statistics, for which the present work adopts a previously proposed approach that employs a parametric model for the channel autocorrelation function and estimates the model parameters from the received DM-RS. While such MIMO transmission is usually considered applicable to slow motion, our results show that the channel estimation technique itself can accommodate much faster motion.

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Evolution of reference signals for LTE-advanced systems

Cited by 52 publications

References 0 publications

Energy Efficient Pilot and Link Adaptation for Mobile Users in TDD Multi-User MIMO Systems

Energy Efficient Pilot and Link Adaptation for Mobile Users in TDD Multi-User MIMO Systems

LTE-Advanced Radio Access Enhancements: A Survey

LMMSE-Based Channel Estimation for LTE-Advanced MIMO Downlink Employing UE-Specific Reference Signals

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