215 research outputs found

    Multicast Scheduling and Resource Allocation Algorithms for OFDMA-Based Systems: A Survey

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    Multicasting is emerging as an enabling technology for multimedia transmissions over wireless networks to support several groups of users with flexible quality of service (QoS)requirements. Although multicast has huge potential to push the limits of next generation communication systems; it is however one of the most challenging issues currently being addressed. In this survey, we explain multicast group formation and various forms of group rate determination approaches. We also provide a systematic review of recent channel-aware multicast scheduling and resource allocation (MSRA) techniques proposed for downlink multicast services in OFDMA based systems. We study these enabling algorithms, evaluate their core characteristics, limitations and classify them using multidimensional matrix. We cohesively review the algorithms in terms of their throughput maximization, fairness considerations, performance complexities, multi-antenna support, optimality and simplifying assumptions. We discuss existing standards employing multicasting and further highlight some potential research opportunities in multicast systems

    WIMAX Basics from PHY Layer to Scheduling and Multicasting Approaches

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    WiMAX (Worldwide Interoperability for Microwave Access) is an emerging broadband wireless technology for providing Last mile solutions for supporting higher bandwidth and multiple service classes with various quality of service requirement. The unique architecture of the WiMAX MAC and PHY layers that uses OFDMA to allocate multiple channels with different modulation schema and multiple time slots for each channel allows better adaptation of heterogeneous user’s requirements. The main architecture in WiMAX uses PMP (Point to Multipoint), Mesh mode or the new MMR (Mobile Multi hop Mode) deployments where scheduling and multicasting have different approaches. In PMP SS (Subscriber Station) connects directly to BS (Base Station) in a single hop route so channel conditions adaptations and supporting QoS for classes of services is the key points in scheduling, admission control or multicasting, while in Mesh networks SS connects to other SS Stations or to the BS in a multi hop routes, the MMR mode extends the PMP mode in which the SS connects to either a relay station (RS) or to Bs. Both MMR and Mesh uses centralized or distributed scheduling with multicasting schemas based on scheduling trees for routing. In this paper a broad study is conducted About WiMAX technology PMP and Mesh deployments from main physical layers features with differentiation of MAC layer features to scheduling and multicasting approaches in both modes of operations

    An Enhanced Feedback-Base Downlink Packet Scheduling Algorithm for Mobile TV in WIMAX Networks

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    With high speed access network technology like WIMAX, there is the need for efficient management of radio resources where the throughput and Qos requirements for Multicasting Broadcasting Services (MBS) for example TV are to be met. An enhanced feedback-base downlink Packet scheduling algorithm that can be used in IEEE 802.16d/e networks for mobile TV “one way traffic”(MBS) is needed to support many users utilizing multiuser diversity of the broadband of WIMAX systems where a group of users(good/worst channels) share allocated resources (bandwidth). This paper proposes a WIMAX framework feedback-base (like a channel-awareness) downlink packet scheduling algorithm for Mobile TV traffics in IEEE806.16, in which network Physical Timing Slots (PSs) resource blocks are allocated in a dynamic way to mobile TV subscribers based on the Channel State information (CSI) feedback, and then considering users with worst channels with the aim of improving system throughput while system coverage is being guaranteed. The algorithm was examined by changing the PSs bandwidth allocation of the users and different number of users of a cell. Simulation results show our proposed algorithm performed better than other algorithms (blind algorithms) in terms of improvement in system throughput performance. Doi: 10.12777/ijse.5.1.55-62 [How to cite this article: Oyewale, J. and , Juan, L.X.. (2013). An Enhanced Feedback-Base Downlink Packet Scheduling Algorithm for Mobile TV in WIMAX Networks. International Journal of Science and Engineering, 5(1),55-62. Doi: 10.12777/ijse.5.1.55-62

    A low complexity resource allocation algorithm for multicast service delivery in OFDMA networks

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    Allocating and managing radio resources to multicast transmissions in Orthogonal Frequency-Division Multiple Access (OFDMA) systems is the challenging research issue addressed by this paper. A subgrouping technique, which divides the subscribers into subgroups according to the experienced channel quality, is considered to overcome the throughput limitations of conventional multicast data delivery schemes. A low complexity algorithm, designed to work with different resource allocation strategies, is also proposed to reduce the computational complexity of the subgroup formation problem. Simulation results, carried out by considering the Long Term Evolution (LTE) system based on OFDMA, testify the effectiveness of the proposed solution, which achieves a near-optimal performance with a limited computational load for the system

    Physical Layer Service Integration in 5G: Potentials and Challenges

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    High transmission rate and secure communication have been identified as the key targets that need to be effectively addressed by fifth generation (5G) wireless systems. In this context, the concept of physical-layer security becomes attractive, as it can establish perfect security using only the characteristics of wireless medium. Nonetheless, to further increase the spectral efficiency, an emerging concept, termed physical-layer service integration (PHY-SI), has been recognized as an effective means. Its basic idea is to combine multiple coexisting services, i.e., multicast/broadcast service and confidential service, into one integral service for one-time transmission at the transmitter side. This article first provides a tutorial on typical PHY-SI models. Furthermore, we propose some state-of-the-art solutions to improve the overall performance of PHY-SI in certain important communication scenarios. In particular, we highlight the extension of several concepts borrowed from conventional single-service communications, such as artificial noise (AN), eigenmode transmission etc., to the scenario of PHY-SI. These techniques are shown to be effective in the design of reliable and robust PHY-SI schemes. Finally, several potential research directions are identified for future work.Comment: 12 pages, 7 figure

    HYBRID ROUTING AND MULTICAST SCHEDULING ALGORITHMS FOR OFDMA RELAY NETWORKS

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    In era of technology, Wireless communication domain growing rapidly due to user mobility & different business operator to deploy Multicast & Broadcast based applications combining video, voice & text. To compute with it; two hop Orthogonal Frequency Division Multiple Access (OFDMA) relay network are being efficiently used in combination with Multicasting which forms a promising communication model for many multiparty applications. We can achieve multiplexing gains in OFDMA network by certain multicast strategy. Grouping of relay network and cooperation between them is one way of multicast strategy. For effective use of relay network, grouping and scheduling for the same must be carried out in intelligent manner. Different scheduling algorithms have been used for different relay network to maximize the multicast flow. While using the scheduling algorithm for OFDMA relay network we have notice the problem of multicast transmission between networks when failure occurs. To solve the problem of multicast transmission when failure occurs one must use dynamic method to choose different path i.e. routing dynamically over the network. Relay network group themselves and cooperate between, also reporting for the failure
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