Frequency Domain Scheduling for OFDMA with Limited and Noisy Channel Feedback

Pedersen, Klaus I.; Monghal, G.; Kovács, István Z.; Kolding, Troels; Pokhariyal, A.; Frederiksen, Frank; Mogensen, Preben

doi:10.1109/vetecf.2007.378

Cited by 86 publications

(57 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In LTE, this is achieved by dynamically changing the Modulation and Coding Scheme (MCS) depending on radio link conditions. Figure 1 shows the structure of the classical LA scheme for the downlink of LTE [23]. LA is performed in the eNodeB based on the feedback from the UE.…”

Section: Link Adaptation Processmentioning

confidence: 99%

Estimating Spectral Efficiency Curves from Connection Traces in a Live LTE Network

Toril

Acedo-Hernández

Sánchez

et al. 2017

Mobile Information Systems

View full text Add to dashboard Cite

In cellular networks, spectral efficiency is a key parameter when designing network infrastructure. Despite the existence of theoretical model for this parameter, experience shows that real spectral efficiency is influenced by multiple factors that greatly vary in space and time and are difficult to characterize. In this paper, an automatic method for deriving the real spectral efficiency curves of a Long Term Evolution (LTE) system on a per-cell basis is proposed. The method is based on a trace processing tool that makes the most of the detailed network performance measurements collected by base stations. The method is conceived as a centralized scheme that can be integrated in commercial network planning tools. Method assessment is carried out with a large dataset of connection traces taken from a live LTE system. Results show that spectral efficiency curves largely differ from cell to cell.

show abstract

Section: Link Adaptation Processmentioning

confidence: 99%

Estimating Spectral Efficiency Curves from Connection Traces in a Live LTE Network

Toril

Acedo-Hernández

Sánchez

et al. 2017

Mobile Information Systems

View full text Add to dashboard Cite

show abstract

“…The identities of the assigned SBs and the MCSs are then conveyed to the users via a downlink control channel. Studies on LTE-related scheduling have been reported in Kwan et al (2008); Liu et al (2007); Ning et al (2006); Pedersen et al (2007);Pokhariyal et al (2007) and the references therein. As pointed out in Jiang et al (2007), the type of traffic plays an important role in how scheduling should be done.…”

Section: /Qdkng Cpf 9ktgnguu %Qoowpkecvkqpu 2j[ukecn Nc[gt Fgxgnqrogpmentioning

confidence: 99%

Downlink Resource Scheduling in an LTE System

Kwan¹,

Leung²,

Zhang³

2010

Mobile and Wireless Communications Physical Layer Development and Implementatiom

View full text Add to dashboard Cite

The problem of allocating resources to multiple users on the downlink of a Long Term Evolution (LTE) cellular communication system is discussed. An optimal (maximum throughput) multiuser scheduler is proposed and its performance is evaluated. Numerical results show that the system performance improves with increasing correlation among OFDMA subcarriers. It is found that a limited amount of feedback information can provide a relatively good performance. A sub-optimal scheduler with a lower computational complexity is also proposed, and shown to provide good performance. The sub-optimal scheme is especially attractive when the number of users is large, as the complexity of the optimal scheme may then be unacceptably high in many practical situations. The performance of a scheduler which addresses fairness among users is also presented.

show abstract

“…Since subcarrier-level feedback consumes considerable uplink bandwidth, several feedback reduction techniques are used in practice [7]- [9]. For example, in the subband-level channel quality indicator (CQI) feedback scheme specified in LTE, each UE feeds back only one 4-bit CQI for every subband.…”

Section: Introductionmentioning

confidence: 99%

“…3 One can, therefore, see that it is quite a challenge to analyze the performance of next generation OFDM systems, such as LTE, that use a spectrally efficient combination of rate adaptation, multiple antenna techniques, and frequencydomain scheduling, and employ EESM to generate CQI feedback. Consequently, most papers that deal with scheduling, adaptation, or CQI feedback for the LTE downlink resort to simulations [9], [12]- [14]. For example, in [13], contiguous and distributed subcarrier allocations are compared by simulations, and their effects on the throughput of greedy and proportional fair (PF) schedulers is evaluated.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

An Accurate Model for EESM and its Application to Analysis of CQI Feedback Schemes and Scheduling in LTE

Donthi

Mehta²

2011

IEEE Trans. Wireless Commun.

View full text Add to dashboard Cite

Abstract-The Effective Exponential SNR Mapping (EESM)is an indispensable tool for analyzing and simulating next generation orthogonal frequency division multiplexing (OFDM) based wireless systems. It converts the different gains of multiple subchannels, over which a codeword is transmitted, into a single effective flat-fading gain with the same codeword error rate. It facilitates link adaptation by helping each user to compute an accurate channel quality indicator (CQI), which is fed back to the base station to enable downlink rate adaptation and scheduling. However, the highly non-linear nature of EESM makes a performance analysis of adaptation and scheduling difficult; even the probability distribution of EESM is not known in closed-form. This paper shows that EESM can be accurately modeled as a lognormal random variable when the subchannel gains are Rayleigh distributed. The model is also valid when the subchannel gains are correlated in frequency or space. With some simplifying assumptions, the paper then develops a novel analysis of the performance of LTE's two CQI feedback schemes that use EESM to generate CQI. The comprehensive model and analysis quantify the joint effect of several critical components such as scheduler, multiple antenna mode, CQI feedback scheme, and EESM-based feedback averaging on the overall system throughput.Index Terms-Effective exponential SNR mapping (EESM), long term evolution (LTE), orthogonal frequency division multiplexing (OFDM), channel quality feedback, multiple antenna diversity, frequency-domain scheduling, adaptive modulation and coding, lognormal random variable.

show abstract

Frequency Domain Scheduling for OFDMA with Limited and Noisy Channel Feedback

Cited by 86 publications

References 10 publications

Estimating Spectral Efficiency Curves from Connection Traces in a Live LTE Network

Estimating Spectral Efficiency Curves from Connection Traces in a Live LTE Network

Downlink Resource Scheduling in an LTE System

An Accurate Model for EESM and its Application to Analysis of CQI Feedback Schemes and Scheduling in LTE

Contact Info

Product

Resources

About