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Heterogeneous networks (HetNets) have been extensively discussed in 3GPP to further enhance the system throughput of traditional well-planned macrocell deployment. In this paper, we consider a HetNet scenario consisting of macro eNBs and low-power nodes implemented as remote radio heads (RRHs) or picos with dedicated carrier deployment. Collaborative inter-site carrier aggregation (CA) is proposed...
This paper presents, through simulation experiments, a performance study of both IEEE 802.11n aggregation methods: A-MPDU (Aggregated MAC Protocol Data Unit) and A-MSDU (Aggregated MAC Service Data Unit), considering scenarios of video streaming. The objectives of this article are: (i) investigate the quality of service achieved, (ii) show which of the two methods of aggregation (A-MPDU or A-MSDU)...
To reduce the feedback load of OFDM-based wireless multicast systems, an opportunistic feedback scheme (OFS) is proposed. OFS aims to only feed the key channel gains that can significantly affect the system throughput back to the base station (BS). By mathematical derivation, the key channel gains are proved to belong to a channel gain interval, which can be estimated by a proposed statistical method...
This paper presents the system performance analysis of 3GPP Long-Term Evolution (LTE) and IEEE 802.11 Wireless Local Area Networks (WLAN) in a situation where LTE downlink (DL) has been expanded over to unlicensed frequency band usually used by WLAN. Simple fractional bandwidth sharing mechanism is used to allow both technologies to transmit. The system performance is evaluated by means of fully dynamic...
A Heterogeneous network (HetNet) of LTE is expected to have macros, picos with biased association, and, femtos in closed access mode. An user equipment (UE) which associates to a pico eNodeB due to biasing experiences severe interference from macro eNodeB. Similarly, a UE associated to the macro eNodeB in the proximity of closed access femto can go into outage due to heavy interference from the femto,...
The 3GPP LTE system has been premeditated to offer extensively higher data rates, higher system throughput, and lower latency for delay critical services. This enhanced performance has to be provided and assured under various mobility circumstances. But, an inappropriate setting of input parameter such as hysteresis margin will lead to an extensive number of handover failures. Hence, handover and...
The method presented in this paper is based on deducing a network graph from an automated material handling system in order to utilize algorithms from graph theory. An optimization process is built on this network structure enabling an improvement of AMHS system performance prior to employment of dynamic simulations. Run time in a static simulation is significantly shorter than that of dynamic simulations,...
Ad hoc On-demand Distance Vector (AODV) is one of reactive routing protocol in Mobile Ad hoc Network (MANET) and many variants are developed based on modifying this protocol. Purposes of modification were mostly related to security and performance improvement, yet the additional processes being introduced in the modification could incur overheads to the modified AODV. The purpose of this paper is...
Smart Home works at the customer domain of the Smart Grid. It aims to provide an interactive environment in which direct communication with end-users can be easily done. Home Area Network adopts Low-Rate Wireless Personal Area Networks (LR-WPANs) to realize the automatic control of lighting system, safety system, smart appliances, smart devices, etc. This paper discusses the architecture of Home Automation,...
The Network-on-Chip (NoC) paradigm has been recently known as a competitive on-chip communication solution for large complex systems such as multi-core and/or many-core systems thanks to its advantages. However, one of the main challenging issues for NoC designers is that the network performance should be rapidly and early pre-proved for target applications. In this paper, we present a NoC simulation...
Cellular data networks are experiencing a serious capacity crunch in the face of exponential increase in mobile data traffic volume. New traffic management techniques are needed to improve network and user perceived performance. In this work, we consider the existence of a higher-layer, agent-based scheduling system that could potentially delay scheduling of low priority flows at peak loads. The priorities...
Out-of-sequence (OOS) is a problem faced by most multistage Clos-network switches. One classical three-stage Clos-network switch structure is to use round-robin to achieve load balancing at the first stage, then switch stage by stage at the latter two stages, using SAR (segments and reassemble) which has to deal with OOS. To address this problem, we propose Frame-based Fair Round-robin (FFRR) for...
In this paper, a new method to improve system performance is presented. In Het-Net of LTE-Advanced system different cells are loaded with difference number of User Equipment (UE). This is because the different transmission powers between macro cell and pico cell are used and the UE moves randomly in the network. Sometimes, a cell could be overloading to server many UEs such that the frequency resource...
Load balancing in ad hoc networks is more challenging issue than that in wired networks because the nature of decentralized network management and terminal mobility makes it difficult to realize appropriate controls for the whole network. Although some traffic-based load balancing methods that work with rerouting mechanisms have been proposed, they are, due to the overhead for rerouting, hard to adapt...
In the cognitive radio networks (CRNs), primary user (PU) has higher priority to access the spectrum band over the secondary user (SU). In this paper, new multichannel priority based cognitive radio (CR) architecture is presented for medium access control (MAC). This multichannel CRN architecture is designed with pre-emptive, non-pre-emptive resume, and pooling priority based systems. Main objective...
This paper presents a load sensing multi-thread web service model, in which web service is abstracted into M/M/c queue, and the optimal thread number is studied. The model introduced a thread performance loss function to reflect the influence of system load on service efficiency. The optimal load sensing thread number is studied by analyzing the relations between service throughput, average response...
Each UE can aggregate multiple component carriers (CCs) as a wider band to support the demand of higher data rates in LTE-Advanced (LTE-A) systems with carrier aggregation (CA). An appropriate CC selection is necessary in order to improve the utility of CA, since not all CCs benefit from CA due to bad channel quality of some CCs. Most of existing methods only take one aspect of problems into account...
This paper studies additional cellular network deployments with the application of coordinated multi-point (CoMP) operation on the LTE-Advanced downlink. It clarifies which approach in additional deployment, either with a macro or pico base station (BS), is the most advantageous to CoMP and spectrum splitting. Cell splitting due to additional deployment is indispensable to having a huge network capacity,...
Load testing of IT applications is fraught with the challenges of time to market, quality of results, high cost of commercial tools, and accurately representing production like scenarios. It would help IT projects to be able to test with a small number of users and extrapolate to scenarios with much larger number of users. This in turn will cut down cycle times and costs and allow for a variety of...
The apparatus of Generalized Nets is applied here to describe a PIM-algorithm for computing a non-conflict schedule for packet switch node. In the present paper we propose a family of patterns for nonuniform traffic simulation based on the hotspot traffic model. The results from computer simulations of the throughput on a switch node with these patterns are presented. The necessary computations have...
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