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The concept of small cells such as femtocell has been regarded as a promising solution to achieve green communication and deal with the coverage hole and growth of traffic within macrocells. However, the unpredictable deployment pattern of such nodes makes static network planing impractical and the overlaying macrocell and femtocell tiers may suffer significant cross-tier interference from each other...
In this paper, we propose a novel cross-layer framework, which includes a two-level resource management to efficiently allocate subchannels among cell BSs (at the super-frame level) and do resource scheduling (at frame level) among intra-cell users based on channel condition and QoS requirement, and a system-level call admission control. The coordination among a plurality of BSs in the OFDMA-based...
Current wireless 4G networks as WiMAX (802.16 d and e) must guarantee quality-of-service (QoS) for fixed and mobile subscribers(SS's). Due to the unpredictable nature of the mobile users in 802.16e, it's challenging to maintain fairness and high bandwidth utilization concurrently while ensuring that QoS requirements are maintained for the different connections. As a user's location changes, so does...
For providing multimedia streaming services in a mobile WiMAX network, it is important to not only optimize the power consumption of mobile stations (MSs) but also satisfy the QoS requirements of the streams. This paper studies the problem of optimizing the power consumption of the mobile stations (MSs) in the cell of a base station (BS) where each MS has several uplink and downlink connections of...
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...
The femtocell deployment in 3GPP/LTE sets new challenges to interference mitigation techniques and Radio Resource Management (RRM). Traditional schemes are mainly designed for classical cellular networks while the ad hoc nature of femtocells notably limits the complexity of possible algorithms. Thus, efficient RRM schemes are essential for limiting the interference impact on end-user performance....
Radio resource management (RRM) is widely regarded as a critical component in improving spectral efficiency of beyond third generation (3G) cellular air interfaces. Much of the published work in Orthogonal Frequency Division Multiplexing (OFDM) RRM focuses on exploiting multi-user, multi-channel and multi-application diversity. In this paper, we propose a Quality of Service (QoS)-aware bit scheduling...
A multichannel scheduling based on an extension of modified largest weighted delay first (M-LWDF) scheduling is proposed for heterogeneous traffic. We consider the downlink of an orthogonal frequency division multiplexing (OFDM) system where the wireless channel and queue state information are taken into account to schedule delay-sensitive and ratesensitive traffic. We propose a logarithmic notion...
Distributed uplink power allocation technique as a strategy for maintaining the quality of service (QoS) is described for orthogonal frequency division multiplexing (OFDM) based networks. In proposed algorithm, the power is allocated to subcarriers having large signal-to-interference-plus-noise ratio (SINR) according to the criterion. In order to reduce cochannel interference, we propose the power...
LTE (Long Term Evolution) supports QoS (Quality of Service) with several service classes. For each class of traffic, a big difference exists on BER (Bit Error Rate) requirement. This leads to a considerable difference in transmission power for various classes of traffic. In this paper, a novel scheduler is designed and proposed for LTE which supports CoS (Class of Service) with the consideration of...
In this paper, we propose a distributed call admission control scheme for multiservice OFDMA system. In our proposed call admission control (CAC) scheme, a cell dynamically adjusts optimal new call and handoff acceptance ratios by three steps. First, exchange numbers of calls in handoff area with its adjacent cells. Then, dynamically allocate resource for different types of traffic. Finally, use a...
The most challenging issue in WiMAX network planning is to measure and enhance the Quality of Service (QoS) of WiMAX networks. In this paper, a comprehensive WiMAX simulator is proposed to evaluate the performance of the system. The key parts of the simulator are described including end-to-end communication path, traffic generation, Medium Access Control (MAC) and Physical (PHY) layers, resource allocation,...
This paper provides a mathematical formulation for Downlink Inter-Cell Interference Coordination (ICIC), in the context of a 3GPP Long-Term Evolution (LTE) Self-Organizing Network (SON). SON concepts have been introduced in LTE standardization in order to increase the network performance and reduce the operational expenditure for operators. Among the proposed SON use cases, ICIC is of utmost importance,...
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 this paper, a new algorithm is proposed for cooperative beamforming in the multiple input multiple output (MIMO) orthogonal frequency division multiple access (OFDMA) cognitive radio (CR) systems. The objective is to maximize the signal to interference plus noise ratio (SINR) of the selected secondary users subject to guarantee the primary user's quality of service over all subchannels. In each...
We study in this paper the resource allocation matter for unlicensed multiband ultra-wideband (UWB) users in the context of high-rate wireless personal area network (WPAN). The problem is viewed as a coexistence problem with existing licensed systems. The QoS support and the interference mitigation are jointly considered in this study to derive a novel interference power control mechanism that differentiates...
As the demand for mobile broadband services are growing, cellular networks are heading towards their fourth generation (4G). Long Term Evolution (LTE) is emerging as a major candidate for 4G cellular networks. 4G networks are to support a myriad of applications which have different error tolerance and delay requirements. MIMO (Multiple Input Multiple Output) technology combined with OFDMA and more...
The major requirement for Cognitive Radio (CR) based opportunistic spectrum re-usage is reliable protection of the primary communication. This calls for a reliable detection of the presence of the Primary Users (PUs) as well as for an immediate reconfiguration of the secondary communication: Each time the PU has been detected, the Secondary Users (SUs) have to vacate the respective part of the spectrum...
In this paper a hybrid automatic repeat request (HARQ) with turbo codes in OFDM system, and the differences hybrid ARQ methods designed for Turbo-coded transmissions on OFDM are presented. Two kinds of modified methods, one without ARQ and the other one are with HARQ: HARQ type-I and HARQ type-II. The latter scheme is based on a combination of the transmitted packets, just before the turbo-decoder...
The problem of resource allocation for the downlink of wireless systems operating over a frequency-selective channel is investigated. It is assumed that the BS (Base Station) uses many antennas and many antennas are available for each user too (Multiple Input Multiple Output - MIMO case). To relieve heavy computational burden, a suboptimal, but efficient algorithm is devised that maximizes the sum...
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