394 research outputs found
Advanced Radio Resource Management for Multi Antenna Packet Radio Systems
In this paper, we propose fairness-oriented packet scheduling (PS) schemes
with power-efficient control mechanism for future packet radio systems. In
general, the radio resource management functionality plays an important role in
new OFDMA based networks. The control of the network resource division among
the users is performed by packet scheduling functionality based on maximizing
cell coverage and capacity satisfying, and certain quality of service
requirements. Moreover, multiantenna transmit-receive schemes provide
additional flexibility to packet scheduler functionality. In order to mitigate
inter-cell and co-channel interference problems in OFDMA cellular networks soft
frequency reuse with different power masks patterns is used. Stemming from the
earlier enhanced proportional fair scheduler studies for single-input
multiple-output (SIMO) and multiple-input multipleoutput (MIMO) systems, we
extend the development of efficient packet scheduling algorithms by adding
transmit power considerations in the overall priority metrics calculations and
scheduling decisions. Furthermore, we evaluate the proposed scheduling schemes
by simulating practical orthogonal frequency division multiple access (OFDMA)
based packet radio system in terms of throughput, coverage and fairness
distribution among users. As a concrete example, under reduced overall transmit
power constraint and unequal power distribution for different sub-bands, we
demonstrate that by using the proposed power-aware multi-user scheduling
schemes, significant coverage and fairness improvements in the order of 70% and
20%, respectively, can be obtained, at the expense of average throughput loss
of only 15%.Comment: 14 Pages, IJWM
Scheduling strategies for LTE uplink with flow behaviour analysis
Long Term Evolution (LTE) is a cellular technology developed to support\ud
diversity of data traffic at potentially high rates. It is foreseen to extend the capacity and improve the performance of current 3G cellular networks. A key\ud
mechanism in the LTE traffic handling is the packet scheduler, which is in charge of allocating resources to active flows in both the frequency and time dimension. In this paper we present a performance comparison of two distinct scheduling schemes for LTE uplink (fair fixed assignment and fair work-conserving) taking into account both packet level characteristics and flow level dynamics due to the random user behaviour. For that purpose, we apply a combined analytical/simulation approach which enables fast evaluation of performance measures such as mean flow transfer times manifesting the impact of resource allocation strategies. The results show that the resource allocation strategy has a crucial impact on performance and that some trends are observed only if flow level dynamics are considered
Analytical Model of Proportional Fair Scheduling in Interference-limited OFDMA/LTE Networks
Various system tasks like interference coordination, handover decisions,
admission control etc. in upcoming cellular networks require precise mid-term
(spanning over a few seconds) performance models. Due to channel-dependent
scheduling at the base station, these performance models are not simple to
obtain. Furthermore, upcoming cellular systems will be interference-limited,
hence, the way interference is modeled is crucial for the accuracy. In this
paper we present an analytical model for the SINR distribution of the
\textit{scheduled} subcarriers of an OFDMA system with proportional fair
scheduling. The model takes the precise SINR distribution into account. We
furthermore refine our model with respect to uniform modulation and coding, as
applied in LTE networks. The derived models are validated by means of
simulations. In additon, we show that our models are approximate estimators for
the performance of rate-based proportional fair scheduling, while they
outperform some simpler prediction models from related work significantly.Comment: 7 pages, 6 figures. This work has been submitted to the IEEE for
possible publication. Copyright may be transferred without notice, after
which this version may no longer be accessibl
Design and development of Modified-Proportional Fair scheduler for LTE/LTE-advanced
Long Term Evolution (LTE) is well known as a cellular network that can support very high data rates in diverse traffic conditions. One way of achieving it is through packet scheduling which is the key scheme of Radio Resource Management (RRM) for LTE traffic processing that is functioning to allocate resources for both frequency and time dimensions. The main contribution of this paper is the design of a new scheduling scheme and its performance is compared with the Proportional Fair (PF) and Round Robin (RR) downlink schedulers for LTE by utilizing LTE Downlink System Level Simulator. The proposed new scheduling algorithm, namely the Modified-PF scheduler divides a single subframe into multiple time slots and allocates the resource block (RB) to the targeted User Equipment (UE) in all time slots for each subframe based on the instantaneous Channel Quality Indicator (CQI) feedback received from UEs. Simulation results show that the Modified-PF scheduler provides the best performance in terms of throughput and spectral efficiency with comparale fairness as compared to RR and PF schedulers. Although PF scheduler has the best fairness index, the Modified-PF scheduler provides a better compromise between the throughput/spectral efficiency and fairness. This shows that the newly proposed scheme improves the LTE output performances while at the same time maintains minimal required fairness among the UEs
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