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Future cognitive radio broadband wireless networks are expected to support a variety of communication services with diverse quality-of-service (QoS) requirements. Multimedia applications such as broadband voice transmission and real-time video streaming are very delay-sensitive and need guaranteed throughput. On the other hand, applications like file transfer and email services are relatively delay...
This paper proposes a novel admission control (AC) algorithm for guaranteed quality of service (QoS) to all users. The proposed solution provides better utilization of system capacity using adaptive modulation (AM). A scheduler based on a per user priority function is also given in this paper. The AC is given by allocating the exact number of slots for each user that will meet its QoS. For every new...
In last few years there has been significant growth in the area of wireless communication. Quality of Service (QoS) has become an important consideration for supporting variety of applications that utilize the network resources. IEEE 802.16/WiMAX is a new network which is designed with quality of service in mind. This paper focuses on the comparison of quality of service parameters between different...
In the last few years, we have witnessed an explosion of IP connectivity demand, translated into a rapid development of the corresponding technologies in the wireless access network domain. IP services provision anytime and anywhere becomes very challenging and is seen by the mobile operators as a major opportunity for boosting the average revenue per unit. The further success of IP services deployment...
In this paper we implement and evaluate two scheduling techniques for mixed data traffic (VoIP and Video Streaming-VS) in LTE systems. We present results regarding resources allocation and traffic evaluation (mean throughput per user) for the Best CQI scheduler and compare to those for a Round Robin (RR) scheduler. Both services are delay-critical services but by prioritizing VoIP in the Best CQI...
The major attraction of the next generation wireless systems such as the third generation partnership project (3GPP) Long Term Evolution (LTE) is the availability of high data-rate video services at high user velocities. However, it is quite a challenge to provide the required level of quality of service (QoS) and maintain the planned system performance due to limited radio resources, unreliable radio...
One of the phenomena that degrades the performance of multicarrier modulation (MCM) systems is the spectral nulls that multipath channel may have. As a result, the affected subcarrier signals may be severely degraded resulting in a loss of symbols. In this paper we have studied how to overcome this problem by taking advantage of spatial diversity along with the knowledge of channel state information...
This paper considered multiuser orthogonal frequency multiple access (OFDMA) scheme, which has been proposed as the transmission technique for 4th Generation (4G) cellular network. An optimum and dynamic radio resource (subcarrier and power) allocation scheme is proposed for OFDMA multiuser system. The proposed algorithm has considered a structured degree of flexibility among the services that can...
This paper proposes a new scheduling algorithm for IEEE 802.16-2005 Broadband Wireless Metropolitan Area Networks in TDD mode. The proposed algorithm focuses on an efficient mechanism to serve high priority traffic in congested networks, without violating the right of lower-priority-traffic to be served in adequate manner. In this work, a detailed simulation study is carried out for the proposed scheduling...
In this paper, we propose a new dynamic frequency assignment scheme for femtoCells in OFDMA networks. The femtoCell base stations are small cellular base stations specially designed to improve the poor indoor coverage and increase the system capacity for cellular and wireless broadband networks. However, these femto-base stations cause harmful interference to the macroCells. Therefore, the optimization...
Cognitive radio is an emerging research topic aiming to improve spectrum usage. This paper deals with resource allocation problem in OFDMA cognitive radio systems. Previous research that has dealt with this problem assume perfect knowledge of the channel state information (CSI) and few works consider the quality of the spectrum sensing in the resource allocation issue. The proposed approach combines...
To improve quality of wireless communication, transmit/receive diversity techniques in multiple-input multiple-output (MIMO) system have been investigated vigorously. In this paper, we consider an asymmetric MIMO orthogonal frequency division multiplexing (MIMO-OFDM) system in the case of high speed mobility for frequency-selective fading channel. For conventional schemes, e.g., cyclic delay diversity...
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...
In this paper, a QoS-guaranteed cross-layer resource allocation algorithm for multiclass services in downlink LTE system is proposed, which takes EXP rule, channel quality variance, real-time services and non-real-time services and minimum transmission rate into account. The key features of the proposed algorithm are that all the users and resource blocks will be allocated step by step respectively...
For a multiuser cognitive OFDM network, most existing adaptive resource allocation methods focus solely on fixed data-rate requirement (QoS guaranteed) or variable data-rate (no QoS guaranteed) conditions without any fairness consideration. In this paper, we investigate the resource allocation problem in a heterogeneous cognitive network with different QoS requirements. By decomposing the problem...
In this paper, we analyze the performance gain achieved when a channel-aware deferring (CaD) strategy is applied to defer the allocation of users with transitory bad channel state in a mobile OFDMA system. Users with good channel conditions receive more resources and the radio resource utilization improves. To reduce the impact of the CaD strategy on the quality of service (QoS) provisioning for the...
OFDM-based communication systems have been widely used in several wireless network applications. In order to achieve a more efficient resource allocation, an novel bit and power allocation algorithm with lifetime consideration is proposed. In this work, the lifetime is specified by the portion of power or energy that a particular user can enjoy during the entire transmission. The proposed algorithm...
This work addresses the application of the cross-layer paradigm to the design of efficient resource allocation algorithms for the downlink of a MIMO-OFDMA system with a physical layer employing optimal single-stream/single-user linear precoding. Mathematical programming tools are used to solve the problem of weighted throughput maximization using both channel state information from the physical layer...
The WiMAX technology based on the IEEE802.16-standard is a Broadband Wireless Access (BWA) technology and considered to be an important ingredient of the composition of the Next Generation Networks (NGN). Till date, due to lack of deployment not enough data is available in terms of its operational capabilities and efficiencies. In this paper, in addition to this standard, some methodologies and paths...
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