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In this paper, we propose a new scheduling mechanism for real time traffic applications for LTE networks considering two scheduler steps. In the first step, we use a system based on the theory of digital filters mechanism called Moving-Average Scheduler. In the second step, the scheduler provides the allocation of resource blocks using a Proportional Fair scheduler. The proposed mechanism is compared...
Quality of service (QoS) aware resource allocation for the uplink of a decode-and-forward relay assisted Orthogonal Frequency Division Multiple Access (OFDMA) based cellular system is investigated. Incorporating relays in the system improves the cell-edge coverage and the system throughput. Resource (relay, subcarrier and power) allocation problem is formulated with the objective of maximizing the...
This paper studies quality-of-service (QoS)-aware frequency provisioning schemes for a downlink multi-user multi-carrier system in a frequency-selective fading environment with diverse user-QoS requirements in terms of target delay and effective capacity (EC). Since a jointly optimal power and sub-carrier allocation requires an exponential-time exhaustive search, we explore an alternative simpler...
The widespread usage of smartphones reveal the necessity of higher data rates in mobile communication networks. LTE, one of the 4th generation cellular technologies, has been developed to meet high capacity needs. LTE enables the digital convergence via carrying audio, video and data traffic over IP packets. In this paper, a novel LTE downlink scheduling algorithm is designed to support Quality of...
This work addresses the design of linear precoders and receivers in multiuser Multiple-Input Multiple-Output (MIMO) downlink channels using Orthogonal Frequency Division Multiplexing (OFDM) modulation when only partial Channel State Information (CSI) is available at the transmitter. Our aim is to minimize the total transmit power subject to per-user Quality-of-Service (QoS) constraints expressed as...
Opportunistic Spectrum Access (OSA) is one of the models proposed for Dynamic Spectrum Access (DSA). In OSA systems, it is important to restrict the interference caused by Secondary Users (SUs) to the Primary Users (PUs). In [1], such an OSA scheme, based on residual idle time distribution of PU traffic, was proposed for a single channel system. In this paper, we suitably modify the above scheme for...
Dynamic spectrum access (DSA) is emerging as a promising technology to mitigate spectrum scarcity caused by static frequency allocation. Among the different models proposed for DSA, opportunistic spectrum access (OSA) is a promising class of solutions. In any DSA system, it is important to make sure that the performance of primary users (PUs) does not degrade significantly as a result of dynamic use...
Adaptive communication is becoming requirement of every communication system for effective utilization of available radio resources. In this approach the transmission parameters like code rate, modulation size and available power are dynamically chosen so that the overall system throughput is maximized while certain constraints like bit error rate are satisfied. In this paper a similar constrained...
Adaptive communication has gained attention of almost every recent communication system because of its rate enhancement and context aware features. In this concept, different transmission parameters like transmit power, forward error correcting (FEC) code rate and modulation scheme are adaptively chosen according to the channel state information. Consequently, that set of transmission parameters is...
This paper proposes an adaptive soft frequency reuse (SFR) scheme with the goal of improving the cell-edge performance as well as the overall cell throughput. The proposed scheme is effective, flexible and cell environments adaptive. Specifically, we consider both consecutive and distributed subcarrier allocation for cell-edge users, and use the QoS deficiency metric to dynamically adjust the subcarrier...
This paper proposes joint user association and energy-efficient resource allocation in the uplink of multi-user two-tier Orthogonal Frequency Division Multiplexing (OFDM) Heterogeneous Networks (HetNets) subject to user's maximum transmission power and minimum-rate constraints. The proposed scheme aims at achieving high rates at low powers satisfying the user's quality-of-service (QoS) constraints...
We propose an energy-efficient network planning scheme for non-contiguous frequency bands based cellular networks. Firstly, the network planning is formulated as a mixed integer programming problem. Main innovations of the proposed model includes: i) a general non-contiguous frequency resource model with hardware capability constraints is proposed, ii) the impact of scheduler on the planning of orthogonal...
Network virtualization is a hot research topic at the moment, and mobile networks are providing services to literally billions of people. Interestingly, the virtualization of complete cellular mobile networks has received little attention up to now, and base station virtualization is a crucial part here. To this end, we propose an architecture for a virtualized base station and examine how the important...
Multimedia traffic is expected to be widespread in next generation wireless networks, which will be likely based on Orthogonal Frequency Division Multiple Access. While multimedia content is heavily demanding in terms of network resources, it is also inherently adaptable at the application layer, thereby imposing soft QoS constraints, rather than strict requirements on a specific data rate. In this...
In this work, a novel particle swarm optimization (PSO) assisted Joint Channel Estimation and Partial Parallel Interference Cancellation (PSO-JCEPPIC) detector is adopted for multiuser Multiple-Input Multiple-Output /Space Division Multiple Access (MIMO-SDMA) Orthogonal Frequency Division Multiplexing (OFDM) systems. The proposed PSO-PPIC scheme tries to reduce the cancellation error in Conventional...
In this paper we emphasis the effect of the variation of major parameters on Orthogonal Frequency Division Multiple Access (OFDMA) systems and the evaluation of channel estimation and equalization are made, in which the bit/symbol error rate of a time varying channel has to be estimated in order to correct the channel interference prior to the decoding of information symbols. We evaluated the channel...
Frequency reuse schemes are an interference management techniques well suited to OFDMA-based cellular networks. In this paper, analytical expressions are derived for the worst case Signal to Interference Ratio (SIR) ratio for both Fractional Frequency Reuse (FFR), and Soft Frequency Reuse (SFR). Also, analytical expressions are derived for the best inner radius using the worst SIR in both FFR, and...
Energy efficiency is crucial in wireless communication systems, especially in cognitive radio (CR) systems in which the exclusive functionality of spectrum sensing inevitably incurs additional energy consumption. In this paper, we study energy-efficient link adaptation for the secondary users (SUs) with heterogeneous quality of service (QoS) requirements in an interference-limited CR system. Two classes...
The aim of this paper is to explore the two most popular wireless networks IEEE 802.11 and IEEE 802.16 with a view to examine the challenges and issues involved in the integration of both the networks. The 802.11 or Wireless Fidelity (WiFi) is a low cost wireless access technology that supports low data rate within a short range. On the contrary, the IEEE 802.16 or WiMAX (Worldwide Interoperability...
A novel analytical framework of multiple radio access technologies (Multi-RAT) communication system is proposed where a small cell serves K mobile users via IEEE 802.11 Wireless Local Area Network (WLAN) and 3GPP Long Term Evolution (LTE) access technologies. A scheduler at the small cell is proposed in order to minimize the total transmission power subject to quality of service constraints on the...
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