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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...
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...
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,...
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...
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...
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...
Scheduling algorithms are very important in WiMAX allowing an efficient radio resources distribution to the uplink and downlink connections. However, the IEEE 802.16 standard does not specify which scheduling algorithm(s) should be used. In this paper, we propose a review of scheduling algorithms proposed for WiMAX / IEEE 802.16 system. We also propose some considerations for the spectrum efficiency...
4G cellular systems and the IMT Advanced candidates will provide broadband wireless access with QoS. Especially in multihop configurations of these systems the base station controls resources centrally while relays can take over a part of the responsibility on the second hop. To make this work on layer two, scheduling is the most important task. However, many dimensions of the problem lead to much...
The IEEE 802.16 Working Group on Broadband Wireless Access is developing the standard for broadband wireless access networks in Metropolitan Area Network (MAN), also know as WiMAX. One of the features of the 802.16 MAC layer 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...
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 while satisfying certain quality of service constrains. In order to mitigate inter-cell and co-channel interference problems in OFDMA cellular networks,...
Scheduling algorithms are very important in WiMAX for the efficient use of radio resources. However, the standard does not specify which scheduling algorithm(s) should be used. A scheduling algorithm should take into account the WiMAX QoS classes and service requirements. The scheduling algorithm also has to taken into account other models of the WiMAX system such as power saving and pricing models...
For the downlink of MIMO-OFDM system, a novel proportional fairness with joint space-time-frequency scheduling is proposed in this paper. On one hand, by space-time-frequency scheduling one can gain multiuser spatial multiplexing on the same subcarrier in one timeslot. On the other hand, with modified traditional proportional fairness, the system can provide QoS guarantee for various service types...
MaxSNR scheduling is acknowledged as the reference resource allocation for multiuser OFDM wireless networks. Well adapted to the wireless environment, MaxSNR opportunistically considers the channel state and fights the multipath fading negative effects. Taking advantage of multiuser diversity, MaxSNR scheduling is well-known for maximizing the global cell throughput. However, throughput maximization...
Fourth generation networks will almost invariably adopt OFDMA (orthogonal frequency division multiple access) and MIMO (multiple input-multiple output) technologies, in order to meet high data rate and quality of service (QoS) requirements. The worldwide interoperability for microwave access (WiMAX) MAC Layer, which is based on the IEEE 802.16 standard, is designed to support a variety of applications,...
In this paper a new permutation zone which combines adjacent and distributed subcarrier permutation is proposed for Orthogonal Frequency Division Multiple Access (OFDMA) systems. For such purpose two types of burst are defined: localized and distributed. A new resource allocation and scheduling algorithm that exploits such structure is then proposed. Furthermore, the effects of limited feedback are...
The challenge of our work is to enhance the effectiveness of packet retransmission in multi-user OFDMA based communication systems. Based on information theory, we propose a retransmission scheduler (re-scheduler) that recomputes the allocation of chunks for negatively acknowledged packets only when correct packet decoding is impossible or it requires a too large number of retransmissions. Our proposal...
We propose two efficient scheduling algorithms for OFDMA networks based on graph theory. The algorithms overcome many drawbacks of previously proposed algorithms such as assuming a single service scenario, limiting the QoS parameters to instantaneous data rate and considering a single OFDM symbol in each scheduling decision. Also, our algorithms enable the system designer to control the tradeoff between...
This paper proposes a channel-adapted and buffer-aware scheduling algorithm in LTE wireless communication system. The scheme allocates system resource jointly PHY-MAC layer according to CQI feed back with the uplink, considers UE buffer status to avoid buffer overflow, and guarantees certain fairness among users. Comparing with traditional scheduling algorithms such as RR, PO and PF, the simulation...
A cross-layer design based on precoding and partial feedback for multiuser MIMO-OFDM systems is presented in this paper. First, we design precoder vectors with partial feedback in order to convert the MIMO channels into equivalent single-input single-output (SISO) channels. Then we can divide the radio resource into many space-time-frequency (STF) three dimension resource units. Then we present a...
In a cellular system with partial channel state information, i.e. with limited feedback, and multiple antennas, we consider scheduling of downlink transmissions at the base station using beamforming and orthogonal frequency division multiplexing. As the complexity of optimal scheduling for throughput maximization under quality of service constraints grows exponentially with the number of subcarriers,...
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