Traffic Sensitive and Traffic Load Aware Path Selection Algorithm For MMR WIMAX Networks

The recent developments in the broadband wireless access (BWA) communication systems have introduced several major changes to the existing systems. Legacy IEEE 802.16j is one such amendment to the existing IEEE 802.16 WiMAX family. The key modification introduced by 802.16j system is the concept of relay station (RS), which may be used to enhance the system coverage or to make system throughput optimal. The end terminals, subscriber stations (SS) are unchanged in the standard. The overall change pertinent to the system has raised many unresolved issues related to RS and multi-hop relay base station (MR-BS). The selection of path from a SS to MR-BS via a RS is also one of the issues, need to be addressed. The path selection of a SS in both uplink and downlink directions is left open in the standard. It is very significant to satisfy the traffics of stringent quality of service (QoS) requirements and to appropriately manage the resources of a cell under different circumstances. This paper proposes a path selection algorithm to achieve the aforementioned qualities in the network. The path selection metrics include traffic load of the transparent relay station and traffic sensitivity factor of the SS. An extensive simulation work discusses the performance evaluation of the proposed work using QualNet simulator

Channel Aware Uplink Scheduler for a Mobile Subscriber Station of IEEE 802.16e

The scheduling part of the IEEE 802.16 (WiMAX) standards is kept as an open issue to provide differentiation among equipment manufacturers and operators. The uplink scheduling is very significant and more complex compared to downlink scheduling. Uplink scheduling is divided into two parts; one is scheduling the resources among many users from a base station (BS) and the other is sharing the resources among its services in a single user. BS uplink scheduling has been given more attention compared to subscriber station (SS) uplink scheduling. SS scheduler plays a significant role in providing the quality of service (QoS) among its services. The channel status awareness is vital in designing the SS scheduler as the channel conditions vary for a mobile user. This work proposes a scheduling algorithm for SS, which utilizes the channel information and queue length variation for the reallocation of received aggregated bandwidth grant to optimize the QoS parameters. The performance of the proposed algorithm is studied by conducting simulations using QualNet 5.0.2 simulation tool. Simulation results demonstrate the effectiveness of the proposed algorithm to improve the QoS

MODULATION AWARE CONNECTION ADMISSION CONTROL AND UPLINK SCHEDULING ALGORITHM FOR WIMAX NETWORKS

Mobile WiMAX standard defines air interface for mobile broadband wireless access (BWA) systems and aimed to provide high data rate with seamless mobility while maintaining the quality of service (QoS). However, QoS of real-time applications depends on the link quality, which necessitate the channel-aware connection admission control (CAC) and scheduling schemes. In this paper Modulation aware CAC scheme and base station (BS) uplink scheduling algorithm are proposed to improve the system capacity and QoS performance respectively. The proposed CAC scheme aims to increase the admission of higher priority real time services by degrading the bandwidth of admitted lower priority connections on the basis of their channel status without deteriorating their QoS performance much. The performances of proposed algorithms are evaluated through simulation by considering the metrics like throughput, delay and number of connections admitted

Performance Evaluation of Connection Admission Control for IEEE 802.16 Networks

Quality of Service (QoS) provisioning to the various kinds of network traffic is one of the major design criteria of IEEE 802.16 WiMAX standard. The MAC and physical layers of 802.16 standards are designed to support different types of real time application by providing QoS. Scheduling, Connection Admission Control (CAC) and traffic policing are the major issues to ensure QoS. In standard, scheduling and admission control are kept as open issues. Admission control is the ability of a network to control admission of new traffic based on the availability of resources. As per the specification the CAC considers minimum reserved rate of a connection as an admission criterion, in which the system can admit more connections, but packets of admitted connection may encounter large delays. In this paper average data rate (avg-rate CAC) and maximum sustained rate (max-rate CAC) of the connections are considered as admission criteria in CAC, along with minimum reserved rate (min-rate CAC). The performance of the WiMAX network is evaluated and compared for min-rate, avg-rate and max-rate CAC by considering the performance metrics such as number of connections admitted, throughput and delay using QualNet simulation tool

Wireless Sensor Networks: A Performance Study of IEEE 802.15.4 Standard

Wireless Sensor Networks (WSN) play a key role in sensing, computing and communicating the information in most of the fields bringing substantial improvements in a broad spectrum of modern technologies. Data to be routed from source to destination is very difficult in WSN due to the mobility of the network elements and lack of central administration. In this paper an attempt has been made to evaluate the performance of routing protocol Ad-hoc On-demand Distance Vector routing (AODV) for the wireless sensor nodes(IEEE 802.15.4 standard). The performance of routing protocol is analysed using various metrics like total packets received, throughput, average end-to-end delay, total bytes received and average jitter using Qualnet 5.0.2 simulator

Effect of integrated nutrient supply on yield and uptake of cardamom (Elettaria cardamomum L. Maton.)

Field experiments were conducted for seven years (2000 to 2007) to assess the effect of integrated nutrient supply with Azospirillum and the combination of Azospirillum, FYM and graded levels of nitrogen on yield and uptake of cardamom. Results revealed that application of FYM @ 5 or 10 kg/plant with or without Azospirillum did not influence the yield components as well as yield levels appreciably. Application of FYM @ 5kg/ plant + 75 % recommended N + Azospirillum yielded 163.53 kg/ha similar to that of FYM @ 5 kg / plant + 100 % recommended N (175.42 kg/ha) and FYM @ 5 kg / plant + 50 % recommended N + Azospirillum yielded 141.20 kg/ha similar to that of FYM @ 5 kg / plant + 75 % recommended N (146.34 kg/ha), thereby providing 25 % saving in inorganic nitrogen. Further, FYM @ 5 kg / plant + 100% recommended N + Azospirillum, responded with 186.48 kg/ha but found on par to FYM @ 5 kg/ plant + 100 % recommended N (175.42 kg/ha). Integrated nutrient management treatments recorded higher nitrogen in plants compared to pure organic treatments. Influence of Azospirillum is not that conspicuous on nitrogen uptake by plants

Scenario Based Study of On-demand reactive routing protocol for IEEE-802.11 and 802.15.4 standards

Routing data from source to destination is hard in Mobile Ad-Hoc Networks (MANET) due to the mobility of the network elements and lack of central administration. The main method for evaluating the performance of MANETs is simulation. In this paper performance of Ad-hoc On-demand Distance Vector (AODV) reactive routing protocol is studied by considering IEEE 802.11 and IEEE 802.15.4 standards. Metrics like average end-to-end delay, packet delivery ratio, total bytes received and throughput are considered for investigating simulation scenario by varying network size with 10 mps node mobility. Also simulation has been carried out by varying mobility for scenario with 50 nodes

A Performance Study of Proactive, Reactive and Hybrid Routing Protocols using Qualnet Simulator

The advancement in information technology and the need for large-scale communication infrastructures has triggered the era of Wireless Sensor Networks (WSNs). Mobile ad-hoc network (MANET) is a network of wireless mobile nodes which communicate with each other without any centralized control or established infrastructure. Routing is the process of selecting paths in a network along which data is to be sent. Routing is a critical task in MANET where the nodes are mobile. Dynamic and reliable routing protocols are required in the ad-hoc wireless networks, as they have no infrastructure (base station) and their network topology changes. There are various protocols for handling the routing problem in the ad-hoc wireless network environment. In this paper focus is given on studying the performance evaluation of various routing protocols using Qualnet simulator 5.0.2. The performance of the proactive, reactive and hybrid protocols are analyzed with different node densities for mobile and stationary nodes. The metrics used for the performance evaluation include average jitter, throughput, packet delivery ratio and average end to end delay

Performance Study of Bandwidth Request Mechanisms in IEEE 802.16e Networks

WiMAX (Worldwide Interoperability for Microwave Access) is the IEEE 802.16 standards-based wireless technology that provides fixed and mobile Internet access for Metropolitan Area Networks (MAN). The IEEE 802.16 std. includes medium access control (MAC) and physical (PHY) layer pecifications and is consider to be a promising technology. Bandwidth reservation is employed to provide quality of service (QoS) to guarantee different services specified in the standard. A bandwidth request/grant scheme is defined in the IEEE 802.16 standard. There are two types of bandwidth request (BR) mechanisms, i.e., polling and contention resolution, which are defined in the standard. As specified, connections belonging to scheduling classes of extended real-time polling service, non-real-time polling service, and best effort have options to make BRs via both mechanisms, depending on the scheduling decision made by the base station (BS). This paper attempts the comparative study of BR mechanisms for different service classes defined in the standard

Simulation and Emulation Approach for the Performance Evaluation of Adaptive Modulation and Coding Scheme in Mobile WiMAX Network

WiMAX is the IEEE 802.16e standard-based wireless technology, provides Broadband Wireless Access (BWA) for Metropolitan Area Networks (MAN). Being the wireless channels are precious and limited, adapting the appropriate modulation and coding scheme (MCS) for the state of the radio channel leads to an optimal average data rate. The standard supports adaptive modulation and coding (AMC) on the basis of signal to interference noise ratio (SINR) condition of the radio link. This paper made an attempt to study the performance of AMC scheme in Mobile WiMAX network using simulation and emulation methods. Different MCS are adopted by mobile subscriber station (MSS) on the basis of the detected instantaneous SINR. Simulation results demonstrate the impact of modulation and coding scheme on the performance of the system and emulation results defend the simulation results