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Spectrum sharing has been recently proposed as a promising paradigm to improve the efficiency of resource usage in next generation mobile networks. In particular, non orthogonal spectrum sharing allows the operators to re-use the available frequencies at the cost of higher interference at the receivers. In this paper, we mathematically analyze the performance of this technique and how it is statistically...
LTE system performance largely depends on the high efficiency of frequency domain resource scheduling. This paper presents a single-cell LTE Downlink scheduling model, and then introduces the economic concept of utility function in order to design a LTE system scheduling algorithm based on the utility function (UBS) and we simulate the algorithm. We simulate and compare throughput, fairness, packet...
This paper studies QoS-guaranteed fair resource allocation and packet scheduling for OFDMA networks. We start with non-traffic-aware weighted generalized proportional fair (WGPF) scheduler and make it a delay-fair scheduler. Delay-fair objective is to equalize delay dissatisfaction measures among users. In this paper the focus is on mean queuing delay. We show how the WGPF objectives are connected...
In MIMO-OFDM multiuser systems, user scheduling is employed as a means of multiple access. In a downlink scenario, users that share the same subcarriers of an OFDM symbol are separated through precoding in order to achieve space division multiple access (SDMA). User scheduling techniques rely on channel knowledge at the transmitter, namely, the so-called channel quality indicator (CQI). In this paper,...
Scheduling is a fundamental component in resource (bandwidth and power) management in NG wireless networks and plays the main role in providing QoS requirements such as delay, throughput and packet loss for different classes of service in 802.16d networks. In this paper we propose a novel scheduling algorithm Strict Priority Based Adaptive modulation and Coding (SP_AMC_Based) that can grantee QoS...
Cellular network capacity and coverage can be improved by deployment of low power base stations referred to as picocells. Due to the associated deployment cost, a large number of picocells challenges the traditional approach to backhaul, where each cell has a dedicated backhaul link. This paper considers a more efficient approach, in which the backhaul is provided over a wireless channel shared among...
We consider the downlink of an OFDM system for supporting a large number of delay-sensitive users. The OFDM scheduling problem can be modeled as a discrete-time multi-source multi-server queuing system with time-varying connectivity. For such a system, the Max-Weight policy is known to be throughput-optimal and the Server-Side Greedy (SSG) policy has been recently shown to achieve small queue lengths...
Cellular base stations typically orthogonalize downlink transmissions, although this approach is not always throughput-optimal. Indeed, it can be shown that removing the orthogonality constraint (as in Superposition Coding) can provide significant benefits in some scenarios. Based on this principle, we propose a scheduling algorithm for a two-user downlink that leverages the disparity in their respective...
In this paper, we present a performance evaluation for six scheduling algorithms over a MIMO-OFDM based cellular system. We have selected a set of scheduling algorithms that may use information about the instantaneous channel conditions, status of transmission queues, QoS requirements or pending HARQ retransmissions. Performance evaluation is focused on average delay under different cell load conditions,...
A novel coordinated scheduling algorithm for OFDM-based systems in multi-cell scenario is proposed in this paper. The studied algorithm based on the utility function is general for the downlink of networks. The algorithm coordinates the subcarrier assignment over the BS cluster. We first establish the framework for this inter-cell coordinated optimization problem through utility-based method. The...
In this paper, we focus on the subcarrier allocation in the uplink of long term evolution advanced (LTE-A) system assuming equal power allocation among subcarriers. Our goal is to maximize the priority-sum in the uplink considering the power limitation of User Equipment (UE). For the purpose, the method to determine the reallocated RBs set and the optimization procedures of reallocated RBs are proposed,...
In a downlink orthogonal frequency division multiple access (OFDMA) system, allocating sub-channels and power across multi-user can require excessive feedback of channel state information. An efficient proportional fair scheduling algorithm based on cluster feedback scheme is proposed in the paper. Simulation results show that the scheme needs only little feedback information while maintaining guaranteed...
Almost all downlink opportunistic resource scheduling algorithms in the multi-user OFDMA system require users' channel quality information (CQI) which is reported to BS using the feedback channel. However, due to the limited bandwidth of the feedback channel, feedback reduction becomes very important in multi-user OFDMA systems. In this paper I propose a new feedback reduction scheme for downlink...
We propose a cross-layer strategy that jointly optimizes user scheduling and resource allocation for adaptive modulation and coding (AMC) based orthogonal frequency multiple access (OFDMA). The objective of this paper is to maximize the system throughput as a function of the bit error rate (BER) and the spectral efficiency based on selected modulation and coding schemes (MCSs). The proposed optimal...
The IEEE 802.16 standard, defining the Worldwide Interoperability for Microwave Access (WiMAX) for Metropolitan Area Network (MAN). The IEEE 802.16 standard, includes specification for the Medium Access Control (MAC) and Physical (PHY) layers, is designed to serve all kinds of traffic. The standard is equipped with signaling and bandwidth allocation algorithms that can accommodate many connections...
WiMAX is a project developed by the Working Group of IEEE 802.16 standard for broadband wireless access networks in Metropolitan Area Network (MAN). One of the features of MAC layer, this standard, is that it is designed to differentiate service among traffic categories with different multimedia requirements. Based on these assumptions and considering that the standard does not specify a scheduling...
A QoS aware multi-traffic scheduling scheme is proposed for multiple traffics to exploit the mutltiuser diversity of NRT users with reduced CQI feedback. In the proposed scheme, the urgent RT users are scheduled first, and then both the remaining RT users and the NRT users are scheduled on the remaining resources at the same time. Based on the proposed scheduling scheme, a reduced feedback strategy...
This paper analyzes the performance of Proportional Fair (PF) scheduling in Orthogonal Frequency Division Multiple Access (OFDMA) wireless systems. OFDMA represents a promising multiple access scheme for high-data-rate transmission over wireless channels as it combines the Orthogonal Frequency Division Multiplexing (OFDM) modulation and subcarrier allocation. On the other hand, the PF scheduling is...
The IEEE 802.16 standards are based on Orthogonal Frequency Division Multiplexing (OFDM) and multi-user OFDM (also known as OFDMA) for their desirable characteristics and potentials. Although well established, these standards only provide a framework of necessary mechanisms for deployable systems. Majority of the resource allocation issues are left unspecified. The conventional one-dimension scheduling...
This paper focuses on multi-user scheduling in downlink relay-aided cellular network. Based on conventional scheduling rules (Round Robin (RR), Max Carrier-to-Interference ratio (Max C/I), and Proportional Fair (PF)), we propose backhaul and access scheduling algorithms under centralized and distributed mechanism, respectively. We evaluate and compare the network performance through system-level simulation...
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